Full utilization of the excited species at both singlet states (1R*) and triplet states (3R*) is crucial to improving electrochemiluminescence (ECL) efficiency but is challenging for organic luminescent materials. Here, an aggregation-induced delayed ECL (AIDECL) active organic dot (OD) containing a benzophenone acceptor and dimethylacridine donor is reported, which shows high ECL efficiency via reverse intersystem crossing (RISC) of non-emissive 3R* to emissive 1R*, overcoming the spin-forbidden radiative decay from 3R*. By introducing dual donor-acceptor pairs into luminophores, it is found that nonradiative pathway could be further suppressed via enhanced intermolecular weak interactions, and multiple spin-up conversion channels could be activated. As a consequence, the obtained OD enjoys a 6.8-fold higher ECL efficiency relative to the control AIDECL-active OD. Single-crystal studies and theoretical calculations reveal that the enhanced AIDECL behaviors come from the acceleration of both radiative transition and RISC. This work represents a major step towards purely organic, high-efficiency ECL dyes and a direction for the design of next-generation ECL dyes at the molecular level.
Pure organic materials with persistent and efficient room-temperature phosphorescence have recently aroused great research interest due to their vast potential in applications. One crucial design principle for such materials is to suppress as much as possible the non-radiative decay of the triplet exciton while maintaining a moderate phosphorescent radiative rate. However, molecular engineering often exhibits similar regulation trends for the two processes. Here, we propose that the quantum interference caused by aggregation can be utilized to control the phosphorescent and non-radiative decay channels. We systematically analyze various constructive and destructive transition pathways in aggregates with different molecular packing types and establish clear relationships between the luminescence characters and the signs of the singlet and triplet excitonic couplings. It is shown that the decay channels can be flexibly switched on or off by regulating the packing type and excitonic couplings. Most importantly, an enhanced phosphorescent decay and a completely suppressed non-radiative decay can be simultaneously realized in the aggregate packed with inversion symmetry. This work lays the theoretical foundation for future experimental realization of quantum interference effects in phosphorescence.
Glioma is one of the most common malignant tumors of the central nervous system, leading high mortality rates in human. Aggregation-induced emission (AIE) photosensitizers-based photodynamic therapy (PDT) has emerged as a promising therapeutic strategy for least-invasive treatment of glioma, which involves local irradiation of the tumor using an external near-infrared (NIR) laser. Unfortunately, most AIE photosensitizers suffered from poorly penetration of the visible light excitation, bad spatiotemporal resolution in deep tissues and low efficient blood-brain barrier (BBB) crossing ability, which greatly limited the clinical practice of AIE photosensitizers for especially deep-seated brain tumor treatment. In this work, we developed a multifunctional NIR-driven theranostic agent through hybrid of AIE photosensitizers TIND with rare-earth doping nanoparticles (RENPs) NaGdF4:Nd/Yb/Tm with up/down dual-mode conversion luminescence. The theranostic agent was further decorated with D-type neuropeptide DNPY for crossing BBB and targeting glioma. Under the 808-nm light irradiation, the down-conversion NIR-II luminescence could indicate the position glioma and the upconversion NIR-I luminescence could trigger the AIE photosensitizers producing reactive oxygen species to inhibit orthotopic glioma tumor growth in situ. These results demonstrate that the integration of Dtype neuropeptide, AIE photosensitizers and RENPs could be promising candidates for in vivo NIR-II fluorescence image-guided through-skull PDT treatments of brain tumors.
Atomically precise metal nanoclusters (MNCs), as a potential type of photoacoustic (PA) contrast agent, are limited in application due to their low PA conversion efficiency (PACE). Here, with hydrophilic Au25SR18 (SR = thiolate) as model NCs, we present a result that weakly polar solvent induces aggregation, which effectively enhances PA intensity and PACE. The PA intensity and PACE are highly dependent on the degree of aggregation, while the aggregation-enhanced PA intensity (AEPA) positively correlates to the protected ligands. Such an AEPA phenomenon indicates that aggregation actually accelerates the intramolecular motion of Au NCs, and enlarges the proportion of excited state energy dissipated through vibrational relaxation. This result conflicts with the restriction of intramolecular motion mechanism of aggregation-induced emission. Further experiments show that the increased energy of AEPA originates from the aggregation inhibiting the intermolecular energy transfer from excited Au NCs to their surrounding medium molecules, including solvent molecule and dissolved oxygen, rather than restricting radiative relaxations. This study develops a new strategy for enhancing the PA intensity of Au NCs, and contributes to a deeper understanding of the origin of the PA signal and the excited state energy dissipation processes for MNCs.
Antibiotic resistance is a major challenge in the clinical treatment of bacterial infectious diseases. Herein, we constructed a multifunctional DNA nanoplatform as a versatile carrier for bacteria-specific delivery of clinical antibiotic ciprofloxacin (CIP) and classic nanoantibiotic silver nanoparticles (AgNP). In our rational design, CIP was efficiently loaded in the self-assembly double-bundle DNA tetrahedron through intercalation with DNA duplex, and single-strand DNA-modified AgNP was embedded in the cavity of the DNA tetrahedron through hybridization. With the site-specific assembly of targeting aptamer in the well-defined DNA tetrahedron, the bacteria-specific dual-antibiotic delivery system exhibited excellent combined bactericidal properties. With enhanced antibiotic accumulation through breaking the out membrane of bacteria, the antibiotic delivery system effectively inhibited biofilm formation and promoted the healing of infected wounds in vivo. This DNAbased antibiotic delivery system provides a promising strategy for the treatment of antibiotic-resistant infections.
The early diagnosis of Parkinson’s disease (PD) provides opportunities for early intervention to slow the progression of neurological degeneration in patients, particularly as the aging population increases in our society. Among a series of pathological features of PD, mitochondria abnormalities have been identified as central event that occurs at the early stage of PD. However, the method for detecting mitochondrial abnormalities-associated early PD has not been fully developed. We herein report a specifically mitochondrial targeting probe (named TPA-BT-SCP) that is able to characterize mitochondria abnormalities for early diagnosis of PD and monitor PD neurodegenerative progress. The probe is an aggregation-induced emission (AIE) probe with a strong positive charge, a 3D distorted molecular structure, and a separated HOMO-LUMO distribution, designed with unique molecular design guidelines. Our research demonstrated that TPA-BT-SCP could emit stable and strong fluorescence, and rapidly accumulate in mitochondria due to the negative charge. After intranasal administration of 1-methy-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice, TPA-BT-SCP successfully bypassed the blood−brain barrier to light up the brain, allowing the grading of PD severity based on its high sensitivity. Taken together, this work develops a novel AIE probe that exhibits dramatically high sensitivity to mitochondrial changes and enables noninvasive diagnosis of early PD in the brain.
Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized, and the thermally activated delayed fluorescence (TADF) property was investigated. Compared to unsubstituted carbazole dendrimers, dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields (PLQY) in neat films. Phenylfluorene (PF)-substituted dendrimers showed the highest PLQY of 81%, a small ΔEst of 0.06 eV, and the fastest reverse intersystem crossing (RISC) rate of ∼1 × 105 s−1 compared to other dendrimers. Phosphorescence measurements of dendrimers and dendrons (fragments) indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons (3LE) to that of phenylfluorene-substituted dendrimers (1CT, 3CT) contributes to RISC promotion and improves TADF efficiency. Terminal modification fine-tunes the energy level and suppresses intermolecular interactions, and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials.
As a high-risk trauma, deep burns are always hindered in their repair process by decreased tissue regeneration capacity and persistent infections. In this study, we developed a simultaneous strategy for deep burn wounds treatment using functional nanovesicles with antibacterial and tissue remodeling properties, delivered via a click-chemistry hydrogel. An aggregation-induced emission photosensitizer of 4-(2-(5-(4-(diphenylamino)phenyl)thiophen-2-yl)vinyl)-1-(2-hydroxyethyl) pyridin-1-ium bromide (THB) with excellent photodynamic properties was first prepared, and then combined with readily accessible adipose stem cells-derived nanovesicles to generate the THB functionalized nanovesicles (THB@ANVs). The THB@ANVs showed strong antibacterial activity against Gram-positive bacteria (up to 100% killing rate), and also beneficial effects on tissue remodeling, including promoting cell migration, cell proliferation, and regulating immunity. In addition, we prepared a click-hydrogel of carboxymethyl chitosan for effective delivery of THB@ANVs on wounds. This hydrogel could be injected to conform to the wound morphology while responding to the acidic microenvironment. In vivo evaluations of wound healing revealed that the THB@ANVs hydrogel dressing efficiently accelerated the healing of second-degree burn wounds by reducing bacterial growth, regulating inflammation, promoting early angiogenesis, and collagen deposition. This study provides a promising candidate of wound dressing with diverse functions for deep burn wound repair.
Recently, many lead-free metal halides with diverse structures and highly efficient emission have been reported. However, their poor stability and single-mode emission color severely limit their applications. Herein, three homologous Sb3+-doped zero-dimensional (0D) air-stable Sn(IV)-based metal halides with different crystal structures were developed by inserting a single organic ligand into SnCl4 lattice, which brings different optical properties. Under photoexcitation, (C25H22P)SnCl5@Sb·CH4O (Sb3+−1) does not emit light, (C25H22P)2SnCl6@Sb-α (Sb3+−2α) shines bright yellow emission with a photoluminescence quantum yield (PLQY) of 92%, and (C25H22P)2SnCl6@Sb-β (Sb3+−2β) exhibits intense red emission with a PLQY of 78%. The above three compounds show quite different optical properties should be due to their different crystal structures and the lattice distortions. Particularly, Sb3+−1 can be successfully converted into Sb3+−2α under the treatment of C25H22PCl solution, accompanied by a transition from nonemission to efficient yellow emission, serving as a “turn-on” photoluminescence (PL) switching. Parallelly, a reversible structure conversion between Sb3+−2α and Sb3+−2β was witnessed after dichloromethane or volatilization treatment, accompanied by yellow and red emission switching. Thereby, a triple-mode tunable PL switching of off–onI–onII can be constructed in Sb3+-doped Sn(IV)-based compounds. Finally, we demonstrated the as-synthesized compounds in fluorescent anticounterfeiting, information encryption, and optical logic gates.
The design of novel materials for sulfur dioxide (SO2) capture and conversion with considerable efficiency under mild conditions is of great significance for human health and environmental protection yet highly challenging. Herein, we report a series of triazine-based multicomponent metallacages via coordination-driven self-assembly of 2,4,6-tri(4-pyridyl)-1,3,5-triazine, cis-Pt(PEt3)2(OTf)2 and different tetracarboxylic ligands. As the increase of the length of the tetracarboxylates, the structures of the metallacages change from pyramids to extended octahedrons. Owing to their N-rich structure, these metallacages are further used for selective SO2 capture, showing good adsorption capacity and remarkable SO2/CO2 selectivity in ambient conditions, suggesting their potential applications toward real flue gas desulfurization. The metallacages are further employed for the conversion of SO2 into value-added compounds, showing exceptional efficiency even dilute SO2 is used as the reactant. This study represents a type of structure-tunable triazinebased metallacages for SO2 capture and conversion, which will pave the way on the applications of metal-organic complexes for gas adsorption.
Three-dimensional (3D) printing is an emerging technique that has shown promising success in engineering human tissues in recent years. Further development of vatphotopolymerization printing modalities has significantly enhanced the complexity level for 3D printing of various functional structures and components. Similarly, the development of microfluidic chip systems is an emerging research sector with promising medical applications. This work demonstrates the coupling of a digital light processing (DLP) printing procedure with a microfluidic chip system to produce size-tunable, 3D-printable porosities with narrow pore size distributions within a gelatin methacryloyl (GelMA) hydrogel matrix. It is found that the generation of size-tunable gas bubbles trapped within an aqueous GelMA hydrogel-precursor can be controlled with high precision. Furthermore, the porosities are printed in two-dimensional (2D) as well as in 3D using the DLP printer. In addition, the cytocompatibility of the printed porous scaffolds is investigated using fibroblasts, where high cell viabilities as well as cell proliferation, spreading, and migration are confirmed. It is anticipated that the strategy is widely applicable in a range of application areas such as tissue engineering and regenerative medicine, among others.
The dual emission (DE) feature in materials holds great potential to revolutionize the development of one-component system white organic light-emitting diodes (WOLEDs). However, the reported DE materials remain scarce owing to the formidable challenge of breaking Kasha’s rule and managing the intricate energy/charge transfer processes. Herein, we have introduced a groundbreaking DE AIEgen, 2CzAn-TPE, which possesses a simple structure and undergoes Z-to-E isomerization and exhibits yellow and red fluorescence powders for pre- and post-sublimation, respectively. With relatively lower potential energy, Z-conformation ((Z)-1,2-diphenyl-1,2-bis(4-(10-(9-phenyl-9H-carbazol-3-yl)anthracen-9-yl)phenyl)ethene) of 2CzAn-TPE can be readily transformed into E-conformation ((E)-1,2-diphenyl-1,2-bis(4-(10-(9-phenyl-9Hcarbazol- 3-yl)anthracen-9-yl)phenyl)ethene) via vacuum sublimation. The utilization of X-ray diffraction and grazing-incidence-wide-angle X-ray scattering techniques confirms the structural transformation, while the crystallographic analysis reveals the establishment of numerous intermolecular CH...π interactions between the tetraphenylethene (TPE) moiety and both the anthracene and carbazole units. This allows a densely packed molecular arrangement, thereby offering propitious conditions for excimer generation in the E-conformation aggregated state. By utilizing the sublimated 2CzAn-TPE as an emitter, a nondoped one-component WOLED was prepared, exhibiting an exceptionally high external quantum efficiency (EQE) of 5.0%, which represents one of the highest performances among all one-componentWOLEDs. This research introduces a novel, simple, and efficient approach to realize highly efficient one-molecule WOLEDs.
The luminescence color of molecule-based photoactive materials is the key to the applications in lighting and optical communication. Realizing continuous regulation of emission color in molecular systems is highly desirable but still remains a challenge due to the individual emission band of purely organic molecules. Herein, a novel alloy strategy based on molecular co-crystals is reported. By adjusting the molar ratio of pyrene (Py) and fluorathene (Flu), three types of molecular co-crystal alloys (MCAs) assemblies are prepared involving Py-Flu-OFN-x%, Py-Flu-TFP-x%, Py-Flu-TCNB-x%. Multiple energy level structure and Förster resonance energy transfer (FRET) process endow materials with tunable full-spectra emission color in visible region. Impressively, these MCAs and co-crystals can be successfully applied to low optical loss waveguide and optical logic gate by virtue of all-color luminescence from blue across green to red, together with smooth surface of onedimensional microrods, which show promising applications as continuous light emitters for advance photonics applications.
The presence of protein aggregates in numerous human diseases underscores the significance of detecting these aggregates to comprehend disease mechanisms and develop novel therapeutic approaches for combating these disorders. Despite the development of various biosensors and fluorescent probes that selectively target amyloid fibers or amorphous aggregates, there is still a lack of tools capable of simultaneously detecting both types of aggregates. Herein, we demonstrate the quantitative discernment of amorphous aggregates by QM-FN-SO3, an aggregationinduced emission (AIE) probe initially designed for detecting amyloid fibers. This probe easily penetrates the membranes of the widely-used prokaryotic model organism Escherichia coli, enabling the visualization of both amorphous aggregates and amyloid fibers through near-infrared fluorescence. Notably, the probe exhibits sensitivity in distinguishing the varying aggregation propensities of proteins, regardless of whether they form amorphous aggregates or amyloid fibers in vivo. These properties contribute to the successful application of the QM-FN-SO3 probe in the subsequent investigation of the antiaggregation activities of two outer membrane protein (OMP) chaperones, both in vitro and in their physiological environment. Overall, our work introduces a near-infrared fluorescent chemical probe that can quantitatively detect amyloid fibers and amorphous aggregates with high sensitivity in vitro and in vivo. Furthermore, it demonstrates the applicability of the probe in chaperone biology and its potential as a high-throughput screening tool for protein aggregation inhibitors and folding factors.
The photothermal conversion capacity of pristine organic phase change materials (PCMs) is inherently insufficient in solar energy utilization. To upgrade their photothermal conversion capacity, we developed bimetallic zeolitic imidazolate framework (ZIF) derived Co/N co-doped flower-like carbon (Co/N-FLC)-based composite PCMs toward solar energy harvesting. 3D interconnected carbon framework with low interfacial thermal resistance, abundant carbon defects and high content of nitrogen doping, excellent localized surface plasmon resonance (LSPR) effect of Co nanoparticles, and light absorber Co3ZnC in Co/N-FLC synergistically upgrade the photothermal capacity of (polyethylene glycol) PEG@Co/N-FLC composite PCMs with an ultrahigh photothermal conversion efficiency of 94.8% under 0.16 W/cm2. Uniformly anchored Co and Co3ZnC nanoparticles in carbon framework guarantee excellent photon capture ability. Bridging carbon nanotubes (CNTs) in 2D carbon nanosheets further accelerate the rapid transport of phonons by constructing cross-connected heat transfer paths. Additionally, PEG@Co/N-FLC exhibits a thermal energy storage density of 100.69 J/g and excellent thermal stability and durable reliability. Therefore, PEG@Co/N-FLC composite PCMs are promising candidates to accelerate the efficient utilization of solar energy.
Aggregation-induced emission (AIE) is a unique phenomenon whereby aggregation of molecules induces fluorescence emission as opposed to the more commonly known aggregation-caused quenching (ACQ). AIE has the potential to be utilized in the large-scale production of AIE-active polymeric materials because of their wide range of practical applications such as stimuli-responsive sensors, biological imaging agents, and drug delivery systems. This is evident from the increasing number of publications over the years since AIE was first discovered. In addition, the evergrowing interest in this field has led many researchers around the world to develop new and creative methods in the design of monomers, initiators and crosslinkers, with the goal of broadening the scope and utility of AIE polymers. One of the most promising approaches to the design and synthesis of AIE polymers is the use of the reversible-deactivation radical polymerization (RDRP) techniques, which enabled the production of well-controlled AIE materials that are often difficult to achieve by other methods. In this review, a summary of some recent works that utilize RDRP for AIE polymer design and synthesis is presented, including (i) the design of AIE-related monomers, initiators/crosslinkers; the achievements in preparation of AIE polymers using (ii) reversible addition-fragmentation chain transfer (RAFT) technique; (iii) atom transfer radical polymerization (ATRP) technique; (iv) other techniques such as Cu(0)-RDRP technique and nitroxide-mediated polymerization (NMP) technique; (v) the possible applications of these AIE polymers, and finally (vi) a summary/perspective and the future direction of AIE polymers.
Quantitatively establishing the correlation between nanoparticle size and fluorescence is essential for understanding the behavior and functionality of fluorescent nanoparticles (FNPs). However, such exploration focusing on organic FNPs has not been achieved to date. Herein, we employ the use of supramolecular polymeric FNPs prepared from tetraphenylethylene-based bis-ureidopyrimidinone monomers (bis-UPys) to relate the size to the fluorescence of organic nanoparticles. At an equal concentration of bis-UPys, a logarithmic relationship between them is built with a correlation coefficient higher than 0.96. Theoretical calculations indicate that variations in fluorescence intensity among FNPs of different sizes are attributed to the distinct molecular packing environments at the surface and within the interior of the nanoparticles. This leads to different nonradiative decay rates of the embedded and exposed bis-UPys and thereby changes the overall fluorescence quantum yield of nanoparticles due to their different specific surface areas. The established fluorescence intensity-size correlation possesses fine universality and reliability, and it is successfully utilized to estimate the sizes of other nanoparticles, including those in highly diluted dispersions of FNPs. This work paves a new way for the simple and real-time determination of nanoparticle sizes and offers an attractive paradigm to optimize nanoparticle functionalities by the size effect.
Understanding the host-guest interactions for thermally activated delayed fluorescence (TADF) emitters is critical because the interactions between the host matrices and TADF emitters enable precise control on the optoelectronic performance, whereas technologically manipulating the singlet and triplet excitons by using different kinds of host-guest interactions remains elusive. Here, we report a comprehensive picture that rationalizes host-guest interaction-modulated exciton recombination by using time-resolved spectroscopy. We found that the early-time relaxation is accelerated in polar polymer because dipole-dipole interaction facilitates the stabilization of the 1CT state. However, an opposite trend is observed in longer delay time, and faster decay in the less polar polymer is ascribed to the π-π interaction that plays the dominant role in the later stage of the excited state. Our findings highlight the technological engineering singlet and triplet excitons using different kinds of host-guest interactions based on their electronic characteristics.
Metal nanoclusters possess excellent electrochemical, optical, and catalytic properties, but correlating these properties remains challenging, which is the foundation to generate electrochemiluminescence (ECL). Herein, we report for the first time that a structurally determined Pt1Ag18 nanocluster generates intense ECL and simultaneously enhances the ECL of carbon dots (CDs) via an electrocatalytic effect. Pt1Ag18 nanocluster show aggregation-induced emission enhancement and aggregation-induced ECL enhancement under light and electrochemical stimulation, respectively. In the presence of tripropylamine (TPrA) as a coreactant, solid Pt1Ag18 shows unprecedented ECL efficiency, which is more than nine times higher than that of 1 mM Ru(bpy)32+ with the same TPrA concentration. Potential-resolved ECL spectra reveal two ECL emission bands in the presence of TPrA. The ECL emission centered at 650 nm is assigned to the solid Pt1Ag18 nanocluster, consistent with the peak wavelength in self-annihilation ECL and photoluminescence of the solid state. The ECL emission centered at 820 nm is assigned to the CDs on the glassy carbon electrode. The electrocatalytic effect of the nanoclusters enhanced the ECL of the CDs by a factor of more than 180 in comparison to that without nanoclusters. Based on the combined optical and electrochemical results, the ECL generation pathways and mechanisms of Pt1Ag18 and CDs are proposed. These findings are extremely promising for designing multifunctional nanocluster luminophores with strong emissions and developing ratiometric sensing devices.
Polymerization-induced self-assembly (PISA) enables the simultaneous growth and self-assembly of block copolymers in one pot and therefore has developed into a high-efficiency platform for the preparation of polymer assemblies with high concentration and excellent reproducibility. During the past decade, the driving force of PISA has extended from hydrophobic interactions to other supramolecular interactions, which has greatly innovated the design of PISA, enlarged the monomer/solvent toolkit, and endowed the polymer assemblies with intrinsic dynamicity and responsiveness. To unravel the important role of driving forces in the formation of polymeric assemblies, this review summarized the recent development of PISA from the perspective of driving forces. Motivated by this goal, here we give a brief overview of the basic principles of PISA and systematically discuss the various driving forces in the PISA system, including hydrophobic interactions, hydrogen bonding, electrostatic interactions, and π-π interactions. Furthermore, PISA systems that are driven and regulated by crystallization or liquid crystalline ordering were also highlighted.
Rheumatoid arthritis (RA) is a debilitating autoimmune disease that causes chronic pain and serious complications, presenting a significant challenge to treat. Promising approaches for treating RA involve signaling pathways modulation and targeted therapy. To this end, a multifunctional nanosystem, TPC-U@HAT, has been designed for RA therapy, featuring multitargeting, dual-stimuli response, and on-demand drug release capabilities. TPC-U@HAT is composed of a probe/prodrug TPC, a JAK1 kinase inhibitor upadacitinib, and the drug carrier HAT. TPC is composed of an aggregation-induced emission (AIE)-active NIR-II chromophore TPY and an NF-κB/NLRP3 inhibitor caffeic acid phenethyl ester (CAPE), connected via boronic ester bond which serves as the reactive-oxygen-species-responsive linker. The carrier, HAT, is created by grafting bone-targeting alendronate and hydrophobic tocopheryl succinate onto hyaluronic acid chains, which can encapsulate TPC and upadacitinib to form TPC-U@HAT. Upon intravenous injection into mice, TPC-U@HAT accumulates at inflamed lesions of RA through both active and passive targeting, and the overexpressed hyaluronidase and H2O2 therein cleave the hyaluronic acid polymer chains and boronate bonds, respectively. This generates an AIE-active chromophore for detection and therapeutic evaluation of RA via both optoacoustic imaging and NIR-II fluorescent imaging and concomitantly releases CAPE and upadacitinib to exert efficacious therapy by inhibiting NF-κB/NLRP3 and JAK-STAT pathways.
Rationally designed multiporphyrinic architectures for boosting photodynamic therapy (PDT) have attracted significant attentions recently years due to their great potential for light-mediated generation of reactive oxygen species. However, there is still a gap between the structure design and their PDT performance for biomedical applications. This tutorial review provides a historical overview on (i) the basic concept of PDT for deeply understanding the porphyrin-mediated PDT reactions, (ii) developing strategies for constructing porphyrinic architectures, like nanorings, boxes, metal-organic frameworks (MOFs), covalent-organic frameworks (COFs), vesicles, etc., where we classified into the following three categories: multiporphyrin arrays, porphyrinic frameworks, and others porphyrin assemblies, (iii) the various application scenarios for clinical cancer therapy and antibacterial infection. Also, the existing challenges and future perspectives on the innovation of porphyrinic architectures for clinical PDT applications are mentioned in the end section. Moreover, the porphyrinic nanomaterials with atomically precise architectures provide an ideal platform for investigating the relationship between structures and PDT outputs, design of personalized “all-in-one” theranostic agents, and the popularization and application in wider biomedical fields.
Molecular rotor-based fluorophores (RBFs) activate fluorescence upon increase of micro-viscosity, thus bearing a broad application promise in many fields. However, it remains a challenge to control how fluorescence of RBFs responds to viscosity changes. Herein, we demonstrate that the formation and regulation of intramolecular hydrogen bonds in the excited state of RBFs could modulate their rotational barrier, leading to a rational control of how their fluorescence can be activated by micro-viscosity. Based on this strategy, a series of RBFs were developed based on 4-hydroxybenzylidene-imidazolinone (HBI) that span a wide range of viscosity sensitivity. Combined with the AggTag method that we previously reported, the varying viscosity sensitivity and emission spectra of these probes enabled a dualcolor imaging strategy that detects both protein oligomers and aggregates during the multistep aggregation process of proteins in live cells. In summary, our work indicates that installing intracellular excited state hydrogen bonds to RBFs allows for a rational control of rotational barrier, thus allow for a fine tune of their viscosity sensitivity. Beyond RBFs, we envision similar strategies can be applied to control the fluorogenic behavior of a large group of fluorophores whose emission is dependent on excited state rotational motion, including aggregation-induced emission fluorophores.
Aggregation-induced emission (AIE) is a phenomenon where a molecule that is weakly or non-luminescent in a diluted solution becomes highly emissive when aggregated. AIE luminogens (AIEgens) hold promise in diverse applications like bioimaging, chemical sensing, and optoelectronics. Investigation in AIE luminescence is also critical for understanding aggregation kinetics as the aggregation process is an essential component of AIE emission. Experimental investigation of AIEgen aggregation is challenging due to the fast timescale of the aggregation and the amorphous aggregate structures. Computer simulations such as molecular dynamics (MD) simulation provide a valuable approach to complement experiments with atomic-level knowledge to study the fast dynamics of aggregation processes. However, individual simulations still struggle to systematically elucidate heterogeneous kinetics of the formation of amorphous AIEgen aggregates. Kinetic network models (KNMs), constructed from an ensemble of MD simulations, hold great potential in addressing this challenge. In these models, dynamic processes are modeled as a series ofMarkovian transitions occurring among metastable conformational states at discrete time intervals. In this perspective article, we first review previous studies to characterize the AIEgen aggregation kinetics and their limitations.We then introduce KNMs as a promising approach to elucidate the complex kinetics of aggregations to address these limitations. More importantly, we discuss our perspective on linking the output of KNMs to experimental observations of time-resolved AIE luminescence. We expect that this approach can validate the computational predictions and provide great insights into the aggregation kinetics for AIEgen aggregates. These insights will facilitate the rational design of improved AIEgens in their applications in biology and materials sciences.
Increasing evidence suggests that intratumoral microbiota plays a pivotal role in tumor progression, immunosurveillance, metastasis, and chemosensitivity. Particularly, in pancreatic ductal adenocarcinoma, tumor-resident Gammaproteobacteria could transform the chemotherapeutic drug gemcitabine (Gem) into its inactive form, thus rendering chemotherapy ineffective. Herein, a strategy for selectively eradicating intratumoral bacteria was described for overcoming Gem resistance in a pancreatic cancer animal model. An antimicrobial peptide was linked with photosensitizer through a poly (ethylene glycol) chain, which can self-assemble into micelles with a diameter of ∼20 nm. The micelles could efficiently kill bacteria under light irradiation by inducing membrane depolarization, thereby inhibiting Gem metabolism. In a bacteria-resident pancreatic cancer animal model, the selective photodynamic eradication of intratumoral bacteria was demonstrated to efficiently reverse Gem resistance. This research highlights antibacterial photodynamic therapy as a promising adjuvant strategy for cancer therapy by modulating intratumoral microbiota.
Developing new photosystems that integrate broad-band near-infrared (NIR) light harvesting and efficient charge separation is a long-sought goal in the photocatalytic community. In this work, we develop a novel photochemical strategy to prepare light-active carbon dots (CDs) under room temperature and discover that the aggregation of CDs can broaden the light absorption to the NIR region due to the electronic couplings between neighboring CDs. Importantly, the dynamic noncovalent interactions within CD aggregates can stabilize symmetry breaking and thus induce large dipole moments for charge separation and transfer. Furthermore, the weak non-covalent interactions allow for flexible design of the aggregated degrees and the local electronic structures of CD aggregates, further strengthening NIR-light harvesting and charge separation efficiency. As a result, the CD aggregates achieve a record apparent quantum yield of 13.5% at 800 nm, which is one of the best-reported values for NIR-light-driven hydrogen photosynthesis to date. Moreover, we have prepared a series of different CDs and also observed that these CDs after aggregation all exhibit outstanding NIR-responsive photocatalytic hydrogen production activity, suggesting the universality of aggregation-enhanced photocatalysis. This discovery opens a new promising platform for using CD aggregates as efficient light absorbers for solar conversion.
Piezoionic materials consisting of a polymer matrix and mobile ions can produce an electrical output upon an applied pressure inducing an ion concentration gradient. Distinct from charges generated by the piezoelectric or triboelectric effects, the use of generated mobile ions to carry a signal closely resembles many ionic biological processes. Due to this similarity to biology, the piezoionic effect has great potential to enable seamless integration with biological systems, which accelerates the advancement of medical devices and personalized medicine. In this review, a comprehensive description of the piezoionic mechanism, methods, and applications are presented, with the aim to facilitate a dialogue among relevant scientific communities. First, the piezoionic effect is briefly introduced, then the development of mechanistic understanding over time is surveyed. Next, different types of piezoionic materials are reviewed and methods to enhance the piezoionic output via materials properties, electrode interfaces, and device architectures are detailed. Finally, applications, challenges, and outlooks are provided.With its novel properties, piezoionics is expected to play a key role in the overcoming of grand challenges in the areas of sensing, biointerfaces, and energy harvesting.
Organic donor-acceptor semiconductors exhibit great potential in photothermal conversion. However, it is still challenging to achieve pure organic materials with broad absorption comparable with inorganic materials such as graphene. Herein, two D-AD type DPA-BT-O4 and NDI-TPA-O4 and three D-A-π-A-D type Th-O4, Th2-O4, and IDT-O4 were readily prepared via two high-yield steps and simple air oxidization. The stability can be attributed to their multiple resonance structures based on the aromatic nitric acid radical mechanism. Compared with the D-A-D radicals, the conjugation extension of the D-A-π-A-D radicals endows them with a narrowed band gap and broad absorption in powder. Interestingly, the IDT-O4 powder with aggregation-induced radical effect exhibits broad absorption between 300 and 2500 nm, which is comparable with graphene and other inorganic materials. Under irradiation of 0.9 W/cm2 (808 nm), the temperature of IDT-O4 powder rises to 250°C within 60 s. The water evaporation conversion efficiency of 94.38% and an evaporation rate of 1.365 kg/m2 h-1 under one sun illumination were achieved. IDT-O4 stands as one of the most efficient photothermal conversion materials among pure organic materials via a rational design strategy.
Engineered nanoparticles have emerged as new types of materials for a wide range of applications from therapeutics to energy. Still, fabricating nanomaterials presenting complex inner morphologies and shapes in a simple manner remains a great challenge. Herein, we report the template-free one-pot continuous gradient nanoprecipitation of different types of non-compatible polymers to spontaneously form nanostructured particles. The continuous addition of antisolvent induces precipitation and (re)organization of polymer chains at the forming particle interface, ultimately and naturally developing complex inner morphologies and shapes while particle grows. This low-energy-cost bottom-up assembly approach applies to various functional polymers, possibly embedded with metal nanoparticles, for continuous growth into well-organized nanoparticles. UV crosslinking of the particles and core removal allows both confirming the building process and leading to hollow or multivoid nanomaterials.
Supercapacitors exhibit considerable potential as energy storage devices due to their high power density, fast charging and discharging abilities, long cycle life, and ecofriendliness. With the increasing environmental concerns associated with synthetic compounds, the use of environment friendly biopolymers to replace conventional petroleum-based materials has been widely studied. Biomass-based materials are biodegradable, renewable, environment friendly and non-toxic. The unique hierarchical nanostructure, excellent mechanical properties and hydrophilicity allow them to be used to create functional conductive materials with precisely controlled structures and different properties. In this review, the latest development of biomass-based supercapacitor materials is reviewed and discussed. This paper describes the physical and chemical properties of various biopolymers and their impact on supercapacitors, as well as the classification and basic principles of supercapacitors. Then, a comprehensive discussion is presented on the utilization of biomass-based materials in supercapacitors and their recent applications across a range of supercapacitor devices. Finally, an overview of the future prospects and challenges pertaining to the utilization of biomass-based materials in supercapacitors is provided.
Natural molecular chaperones utilize spatially ordered multiple molecular forces to effectively regulate protein folding. However, synthesis of such molecules is a big challenge. The concept of “aggregate science” provides insights to construct chemical entities (aggregates) beyond molecular levels to mimic both the structure and function of natural chaperone. Inspired by this concept, herein we fabricate a novel multi-interaction (i.e., electrostatic and hydrophobic interaction) cooperative nanochaperone (multi-co-nChap) to regulating protein folding. This multi-co-nChap is fabricated by rationally introducing electrostatic interactions to the surface (corona) and confined hydrophobic microdomains (shell) of traditional single-hydrophobic interaction nanochaperone. We demonstrate that the corona electrostatic attraction facilitates the diffusion of clients into the hydrophobic microdomains, while the shell electrostatic interaction balances the capture and release of clients. By finely synergizing corona electrostatic attraction with shell electrostatic repulsion and hydrophobic interaction, the optimized multi-co-nChap effectively facilitated de novo folding of nascent polypeptides. Moreover, the synergy between corona electrostatic attraction, shell electrostatic attraction and shell hydrophobic interaction significantly enhanced the capability of multi-co-nChap to protect native proteins from denaturation at harsh temperatures. This work provides important insights for understanding and design of nanochaperone, which is a kind of ordered aggregate with chaperone-like activity that beyond the level of single molecule.
Centrifugal and shear forces are produced when solids or liquids rotate. Rotary systems and devices that use these forces, such as dynamic thin-film flow technology, are evolving continuously, improve material structure-property relationships at the nanoscale, representing a rapidly thriving and expanding field of research high with green chemistry metrics, consolidated at the inception of science. The vortex fluidic device (VFD) provides many advantages over conventional batch processing, with fluidic waves causing high shear and producing large surface areas for micro-mixing as well as rapid mass and heat transfer, enabling reactions beyond diffusion control. Combining these abilities allows for a green and innovative approach to altering materials for various research and industry applications by controlling small-scale flows and regulating molecular and macromolecular chemical reactivity, self-organization phenomena, and the synthesis of novel materials. This review highlights the aptitude of the VFD as clean technology, with an increase in efficiency for a diversity of top-down, bottom-up, and novel material transformations which benefit from effective vortex-based processing to control material structure-property relationships.
The efficacy of nanoparticle (NP)-based drug delivery technology is hampered by aberrant tumor stromal microenvironments (TSMs) that hinder NP transportation. Therefore, the promotion of NP permeation into deep tumor sites via the regulation of tumor microenvironments is of critical importance. Herein, we propose a potential solution using a dihydralazine (HDZ)-loaded nanoparticle drug delivery system containing a pH-responsive, cyclic RGD peptide-modified prodrug based on doxorubicin (cRGD-Dex-DOX). With a combined experimental and theoretical approach, we find that the designed NP system can recognize the acid tumor environments and precisely release the encapsulated HDZ into tumor tissues. HDZ can notably downregulate the expression levels of hypoxia-inducible factor 1α (HIF1α), α-smooth muscle actin, and fibronectin through the dilation of tumor blood vessels. These changes in the TSMs enhance the enrichment and penetration of NPs and also unexpectedly promote the infiltration of activated T cells into tumors, suggesting that such a system may offer an effective “multifunctional therapy” through both improving the chemotherapeutic effect and enhancing the immune response to tumors. In vivo experiments on 4T1 breast cancer bearing mice indeed validate that this therapy has the most outstanding antitumor effects over all the other tested control regimens, with the lowest side effects as well.
Nowadays, cancer has become the leading cause of death worldwide, driving the need for effective therapeutics to improve patient prognosis. Photodynamic therapy (PDT) has been widely applied as an antitumor modality, owing to its minimal invasiveness, localized tumor damage, and high safety profile. However, its efficacy is limited by poor stability of photosensitizers, inadequate tumor accumulation, and a complex tumor microenvironment. To overcome these challenges, extensive endeavors have been made to explore the co-assembly of the widely used photosensitizer chlorin e6 (Ce6) with various functional small molecules to enhance pharmacodynamic activity. This review provides a comprehensive overview of current studies on Ce6-based nanoparticles for effective PDT and precise delivery of functional molecules. The self-assembly mechanism will be discussed in detail, with a focus on potential strategies for combinational therapy with PDT.
Efficient and cost-effective electrocatalysts that can operate across a wide range of pH conditions are essential for green hydrogen production. Inspired by biological systems, Fe7S8 nanoparticles incorporated on polydopamine matrix electrocatalyst were synthesized by co-precipitation and annealing process. The resulting Fe7S8/C electrocatalyst possesses a three-dimensional structure and exhibits enhanced electrocatalytic performance for hydrogen production across various pH conditions. Notably, the Fe7S8/C electrocatalyst demonstrates exceptional activity, achieving low overpotentials of 90.6, 45.9, and 107.4 mV in acidic, neutral, and alkaline environments, respectively. Electrochemical impedance spectroscopy reveals that Fe7S8/C exhibits the lowest charge transfer resistance under neutral conditions, indicating an improved proton-coupled electron transfer process. Continuous-wave electron paramagnetic resonance results confirm a change in the valence state of Fe from 3+ to 1+ during the hydrogen evolution reaction (HER). These findings closely resemble the behavior of natural [FeFe]-hydrogenase, known for its superior hydrogen production in neutral conditions. The remarkable performance of our Fe7S8/C electrocatalyst opens up new possibilities for utilizing bioinspired materials as catalysts for the HER.
For more than a decade, the discovery of liquid–liquid phase separation within living organisms has prompted colloid scientists to understand the connection between coacervate functionality, phase behavior, and dynamics at a multidisciplinary level. Although the protein–polysaccharide was the first system in which the coacervation phenomenon was discovered and is widely used in food systems, the phase state and relaxation dynamics of protein–polysaccharide complex coacervates (PPCC) have rarely been discussed previously. Consequently, this review aims to unravel the relationship between PPCC dynamics, thermodynamics, molecular architecture, applications, and phase states in past studies. Looking ahead, solving the way molecular architecture spreads to macro-functionality, that is, establishing the relationship between molecular architecture–dynamics–application, will catalyze novel advancements in PPCC research within the field of foods and biomaterials.
Peculiar hierarchical microstructures in creatures inspire modern material design with distinct functionalities. Creatures can effortlessly construct sophisticated yet long-range ordered microstructure across bio-membrane through ion secretion and precipitation. However, microstructure biomimicry in current technology generally requires elaborate, point-by-point fabrication. Herein, a spontaneous yet controllable strategy is developed to achieve surface microstructure engineering through a natural surface phenomenon similar to ion secretion-precipitation, that is, coupled dissolution-precipitation. A series of hierarchical microstructures on mineral surfaces in fluids with tunable morphology, orientation, dimension, and spatial distribution are achieved by simply controlling initial dissolution and fluid chemistry. In seawater, long-range ordered film of vertically aligned brucite flakes forms through interfacial dissolution, nucleation, and confinement-induced orientation of flakes with vertically grown {110} plane, on the edge of which, fusiform aragonite epitaxially precipitates. With negligible initial surface dissolution, prismatic aragonite epitaxially grows on a calcite polyhedron-packed surface. By tuning fluid chemistry, closely packed calcite polyhedron and loosely packed calcite micro-pillars are engineered through rapid and retarded precipitation, respectively. Surprisingly, the spontaneously grown microstructures resemble those deliberately created by human or found in nature, and tremendously modulate surface functionality. These findings open new possibilities for facile and customizable engineering of microstructural surfaces, hierarchical heterostructures, and biomimetic materials.
High-pressure chemistry has provided a huge boost to the development of scientific community. Pressure-induced emission (PIE) in halide perovskites is gradually showing its unique charm in both pressure sensing and optoelectronic device applications. Moreover, the PIE retention of halide perovskites under ambient conditions is of great commercial value. Herein, we mainly focus on the potential applications of PIE and PIE retention in metal halide perovskites for scintillators and solid-state lighting. Based on the performance requirements of scintillator and single-component white light-emitting diodes (WLEDs), the significance of PIE and PIE retention is critically clarified, aiming to design and synthesize materials used for high-performance optoelectronic devices. This perspective not only demonstrates promising applications of PIE in the fields of scintillators and WLEDs, but also provides potential applications in display imaging and anti-counterfeiting of PIE materials. Furthermore, solving the scientific disputes that exist under ambient conditions is also simply discussed as an outlook by introducing high-pressure dimension to produce PIE.