Photoacoustic imaging (PAI) uniquely merges the molecular contrast of optical absorption with the centimeter-scale penetration afforded by ultrasound detection, enabling noninvasive visualization of deep physiology beyond the reach of purely optical modalities. Conventional photoacoustic (PA) contrast agents have been used to improve detection sensitivity relative to endogenous absorbers, but their fixed optical properties limit adaptation to heterogeneous or evolving disease microenvironments. Activatable PAI contrast agents overcome this drawback by switching their absorbance spectra in real time in response to exogenous triggers (near-infrared light, heat, ultrasound, and electromagnetic fields) or endogenous microenvironmental cues (hypoxia, pH, reactive oxygen species, glutathione, and disease-related enzymes). These dynamic features extend PAI beyond static signal enhancement, enabling user-controlled activation, suppression of background interference, and access to functional or molecular biomarkers that conventional agents cannot provide. This review surveys recent advances in the molecular design, activation chemistry, and biomedical applications of these “activatable” probes, highlighting strategies for noninvasive diagnosis, multimodal imaging, remote actuation, and synergistic theranostics. Looking ahead, the next frontier lies in pathology-tailored probes that can noninvasively reveal biomarkers inaccessible to current methods, as illustrated by early successes in atherosclerosis imaging. Achieving this translation will require optimizing probe safety and clearance, standardizing characterization protocols, and integrating hybrid imaging platforms with quantitative PA tomography to generate reliable diagnostic metrics.

Artificial photoreceptors capable of eliciting neural responses offer a promising strategy for restoring vision in individuals with retinal degenerative diseases. However, stimulating neurons under low-intensity light remains a critical challenge, which significantly hampers their practical application. Here, a flexible arched artificial photoreceptor with strong photoelectric response under weak light is constructed by photodeformable liquid crystal polymers (LCPs) and polyvinylidene fluoride-trifluoroethylene (P(VDF-TrFE)). The light-stress-electricity conversion arising from photo-induced stress of LCPs and the piezoelectric effect of P(VDF-TrFE) is significantly enhanced by the arched structure, which induces stress concentration. Hence, the open-circuit voltage reaches up to 17.51 ± 0.60 V under 8 mW cm⁻² light irradiation, which is 21 times higher than that of the planar structure (0.79 V), with a 10-fold reduction in light intensity. By analyzing the voltage of units, the pixelated matrix of artificial photoreceptors is capable of imitating complex visual functions including light detection, pattern recognition and information decoding. Notably, the flexibility and biocompatibility endow this artificial photoreceptor with great potential in artificial retinal applications. Blind rats implanted with this artificial photoreceptor are demonstrated to exhibit restored visual responses. This study presents a novel approach to fabricating artificial photoreceptors which are sensitive to weak light and provides new insights for the applications of LCPs in implantable devices.

Photodynamic immunotherapy (PDIT) integrates reactive oxygen species (ROS)-mediated tumor destruction with immune activation. However, its effectiveness is often hindered by tumor hypoxia, poor tumor-targeted delivery, and the immunosuppressive microenvironment. Here, we introduce BDPM@OMVs, a biomimetic nanoplatform designed to overcome these challenges. This system uses bacterial outer membrane vesicles to encapsulate a novel, heavy-atom-free aggregation-induced emission photosensitizer (BDPM). Our platform enables stepwise lysosome-to-mitochondria trafficking for enhanced PDIT. BDPM@OMVs exhibits strong near-infrared absorption and efficient intersystem crossing, leading to both Type I and Type II ROS generation, which sustains photodynamic performance even under hypoxic conditions. Upon light irradiation, BDPM@OMVs trigger photochemical internalization (PCI), disrupting lysosomes and releasing BDPM into the cytosol. The freed BDPM then selectively accumulates in mitochondria, where continues light exposure generates robust ROS, causing mitochondrial dysfunction and activating apoptosis. This process effectively amplifies tumor cell eradication. Simultaneously, BDPM@OMVs reprogram the tumor immune microenvironment by promoting macrophage repolarization from the immunosuppressive M2 to the pro-inflammatory M1 phenotype, as evidenced by upregulated TNF-α, IL-1β, and CD86 expression. In vivo studies confirm that BDPM@OMVs achieve efficient tumor accumulation, allow for real-time NIR imaging, and provide superior therapeutic outcomes. This work presents a versatile and hypoxia-resilient PDIT strategy that synergistically integrates precise subcellular photodamage with immune modulation to overcome resistance in solid tumors.

Zeolitic imidazolate framework-67 (ZIF-67) has emerged as a promising carrier for active substances (AS) due to its biocompatibility and acid-triggered degradation behavior. Conventional loading strategies often involve multi-step post-synthetic modifications or one-pot processes employing toxic organic solvents. This study presents a facile one-pot synthesis method for encapsulating AS into ZIF-67 in deionized water within 2 h under ambient conditions. This method exhibits broad applicability, enabling effective encapsulation of both hydrophobic and hydrophilic molecules with molecular weights ranging from low to high, with loading efficiencies between 12.17% and 56.11%. While free compounds were released rapidly in a pH-independent manner, both CA@ZIF-67 and EGCG@ZIF-67 proved pH-responsive sustained release profiles, with their mechanisms best described by the first-order model and Fickian diffusion, respectively. Moreover, these composites demonstrated synergistic and pH-dependent antibacterial activity against Escherichia coli and Staphylococcus aureus, showing significantly enhanced efficacy in acidic conditions. Furthermore, the formation process, morphological evolution, and release behavior of AS@ZIF-67 composites were elucidated through Monte Carlo simulations, modified attachment energy theory, and molecular dynamics simulations. This green one-pot strategy offers a versatile platform for applications in controlled release, antimicrobial systems, and targeted delivery.

This study herein presents the rational design and synthesis of a series of meso-CF₃-substituted BODIPY dyes to achieve controllable molecular aggregation and enhanced near-infrared (NIR) phototherapeutic performance. By constructing a D-A-D architecture and introducing furan/thiophene groups, the resulting BODIPYs (OBB, OHB, SBB and SHB) form distinct intermolecular aggregates. Single-crystal X-ray diffraction analyses reveal that specific hydrogen-bonding interactions (C-H⋯F), with precise distances ranging from 2.336 Å to 2.542 Å, induce self-assembly to form hydrogen-bonded-mediated J aggregates. This controlled aggregation induces significant bathochromic shifts, extending absorption into the NIR-I and NIR-II regions (up to 937 nm in film), and generates broad absorption bands beneficial for laser matching. Among the self-assembled nanoparticles (NPs), OBB NPs demonstrate superior properties, including a high photothermal conversion efficiency of 49.7%, a large Stokes shift (87 nm) in water, and type-I reactive oxygen species generation. In vitro studies against ovarian cancer cells confirm that OBB NPs exhibit low dark toxicity but potent photo-triggered cytotoxicity, effectively inducing cell apoptosis and necrosis through an ROS-mediated mechanism. This work underscores the critical role of intermolecular hydrogen bonding in manipulating aggregation-induced optical properties and provides a fundamental strategy for developing highly effective organic phototherapeutic agents.

Messenger RNA (mRNA) therapy has been explored as a treatment for various genetic disorders. Significant progress has been made in developing mRNA delivery systems. However, efficient delivery of mRNA in hard-to-transfect cells remains a considerable challenge. Here, we constructed a series of spiropyran-derived lipid-like materials, named SPALs, to enhance mRNA delivery efficiency in cells that are difficult to transfect. In this design, we focused on strengthening the internal escape mechanism of mRNA nanoparticles via photo-induced proton production by SPALs. Specifically, the spiropyran structure can undergo ring-closing isomerization under light irradiation (460 nm) and produce a proton. The protons then mediate the protonation of tertiary amines in the lipid tail in situ, which subsequently disrupts the potential and size of nanoparticles and finally promotes their endosome escape. It ultimately enhances mRNA expression in live cells. SPALs are demonstrated to reduce the pH value up to 0.53 pH units after light irradiation in solution. They are also proven to decrease the pH value after light irradiation as observed through fluorescence ratio imaging in live cells. After screening the materials, we identified SPAL1 as a lead material for increasing the enhanced green fluorescent protein-positive rate in Raw 264.7 cells by 22% after light irradiation, from 59% to 72%. This transfection efficiency is significantly higher than that of the lipo3000 in the same cell line. Consequently, we developed a new strategy to improve mRNA transfection efficiency, which merits further evaluation and development for mRNA-based therapy.

Viscosity is one of the important microenvironmental parameters of abiotic stress. Abnormal changes in viscosity have been shown to be correlated with pathological activities and diseases of plants. However, current probes may not be suitable for sensing in plants due to their hydrophobicity and the phytochromes found in plants. With this research, we successfully constructed a structurally simple, water-soluble near-infrared fluorescent probe HJA-MQ-D, which can simultaneously monitor dynamic viscosity changes in plants and animal systems. The probe exhibits a relatively long emission wavelength (nearly 700 nm) and large Stokes shift (88 nm), and exceptional viscosity-responsive performances with 140-fold fluorescence intensity enhancement. More importantly, the HJA-MQ-D can image the viscosity fluctuation at the cellular level in plants (onion inner epidermis and mung bean sections) as well as at the whole-plant level (mung bean and peanut seedling). In addition, HJA-MQ-D was used to monitor the viscosity changes in a nystatin-induced zebrafish model. Based on these advanced characteristics, we anticipate that this probe will provide a powerful new tool for cross-species viscosity monitoring.

Heart failure (HF), a major global health challenge with high morbidity and mortality, lacks effective biomarkers and non-invasive tools for early diagnosis and therapy evaluation. Endogenous carbon monoxide (CO), a key biological signaling molecule, is closely linked to cardiovascular diseases such as HF when dysregulated. Integrating near-infrared (NIR) fluorescence (FL) imaging with photoacoustic (PA) imaging offers a powerful approach, as the 2D FL data can validate and supplement the 3D PA information for a more holistic disease assessment. Herein, we developed CS-CO, an activatable dual-mode NIR probe for the selective monitoring of CO fluctuations in HF. Density functional theory (DFT) calculations validated the design, elucidating the signal turn-on mechanism upon CO binding. The metal-free CS-CO probe selectively detects CO, resulting in activated NIR absorption (710 nm) and emission (742 nm). Consequently, its excellent NIR PA and FL performance allowed for visualizing both exogenous and endogenous CO in cells, and for 2D FL and 3D PA imaging in mice. Crucially, using this dual-mode imaging approach, CS-CO successfully revealed dynamic CO level changes during both HF progression and drug-induced reversal for the first time. This study provides a pioneering strategy for early HF diagnosis and drug efficacy evaluation, with significant potential clinical impact.

Molecule-based devices that combine the advantages of fast time response and extremely low manipulation/transmission energy consumption of light, as well as the non-volatile properties of magnetic storage, could potentially be the ideal choice for future information processing. The key to achieving this vision lies in the bridge between light and magnetism, which refers to the innovative magneto-optical functional materials. The discovery of molecular magnets with spin-crossover features provides a new inspiration for realizing magneto-optical fusion information technology. Here, we demonstrate that light can reversibly modulate the propagation of magnons in cyanide bridged alternating W(V)-Fe(II) coordination polymer chains, wherein the paramagnetic high-spin and diamagnetic low-spin states of Fe(II) ions can be interconverted by alternating 808- and 473-nm light irradiations. Our experiments exploit microwaves for spin injection and detection, revealing that characteristic signal peaks at 8.28–8.60 GHz can be modulated by alternating light irradiation. The experimental results relate this phenomenon to the difference in magnon excitation between different spin states resulting from photo-induced spin-state switching. This photo-modulated spin transport device, which exhibits the properties of nonvolatility and reproducibility, provides a revolutionary strategy for modulating magnons and paving the way for optically tunable, ultrafast, low-power, and organic-insulator-based spin-logic devices.

In this study, a series of benzophenone (BP)-based photoinitiators (PIs), designated as BP-Sn, were synthesized by the integration of small molecule hydrogen donors into the BP scaffold. This design aims to minimize reliance on co-initiators, reduce potential odors and toxicities, and enhance initiation efficiency of PIs under LED irradiation. Additionally, the incorporation of thioether linkages imparts a distinctive dual functionality to PIs, enabling them to exhibit both hydrogen-abstracting (Type II) and bond-breaking (Type I) characteristics. The photophysical and photoinitiation properties of BP-Sn were evaluated using electron paramagnetic resonance, UV-visible spectrophotometry, and real-time Fourier-transform Infrared spectroscopy. The findings demonstrate that BP-Sn exhibit remarkable efficacy as a single-component PI for free-radical polymerization, achieving a final conversion efficiency approaching 95% and a photoinitiation rate exceeding 20% s⁻¹ for the polymerization of tripropylene glycol diacrylate without the need for additional co-initiators. Furthermore, the polymerization experiment revealed that exposure to 365 nm LED light for just 2 min results in the formation of a colorless and well-defined patterned texture, with a thickness of 5 mm and a diameter of 7 cm, demonstrating its potential practical applications.