Antimicrobial resistance caused by overuse of antibiotics has promoted the demand for effective antibacterial materials. However, the development of existing antibacterial strategies mostly focuses on direct sterilization, which may lead to flora imbalance and drug resistance. Here, a series of peptide-based aggregation-induced emssion nanomaterials (PBANs) with multiple structural domains were designed by mimicking the self-assembly of human α-defensin 6. Specifically, PBANs self-assemble to form nanoparticles in physiological environments and in situ transform into nanofibers on bacterial surfaces through receptor-ligand interactions in infected microenvironments, resulting in enhanced fluorescence signal and activation of functions, while labeling and entrapping bacteria. Different from traditional antibacterial strategies that directly kill pathogenic microorganisms, PBANs can inhibit bacterial motility and invasion into the host system through physical barriers and affecting energy metabolism pathways. In addition, PBANs can further recruit macrophages to the infection site to engulf entrapped bacteria, thereby synergistically reducing the infection efficiency. In mouse and piglet systemic infection models, the PBANs showed favorable therapeutic efficacy, significantly reducing bacterial load and levels of inflammation factors. Overall, this study provides perspectives for developing biomimetic stimuli-responsive nanomaterials to combat bacterial infections.
Research on optoelectronic synapses that can integrate both detection and processing functions is essential for the development of efficient neuromorphic computing. Here, we experimentally demonstrated an Ga2O3-based metal–semiconductor–metal (MSM) solar-blind ultraviolet (UV) photodetector (PD) with asymmetric interdigital electrodes. The Ga2O3 PD exhibits a responsivity of 732 A/W under a forward bias of 6 V. The tunable conductance properties of PDs provide a novel approach to synaptic performance. The proposed PDs as artificial synapse realized several essential synaptic function, including excitatory postsynaptic current, paired-pulse facilitation, long-term potentiation, the transition from short-term memory to long-term memory, and learning experience behaviors successfully. At a reverse bias, an ultra-low energy consumption of 140 fJ was achieved. In addition, the optoelectronic synapses demonstrated a recognition accuracy of over 95% in the MNIST handwritten number recognition task. These results suggest that Ga2O3 MSM solar-blind UV PDs have high potential for efficient optoelectronic neuromorphic computing applications.
Hypochlorous acid (HClO), a key member of the reactive oxygen species, has an impact on both normal and abnormal functioning of a wide range of organisms. To deeply investigate the function of HClO in organisms and its impact on health status, there is an urgent need to develop efficient detection techniques in the biomedical field. Herein, a highly selective and sensitive hypochlorite fluorescent probe (Py-DA) was designed and synthesized. Photophysical property tests and response behavior studies of Py-DA showed high-performance turn-on detection of HClO/ClO−, including fast response, high sensitivity, excellent selectivity, and strong anti-interference capabilities. Significantly, the emission intensity showed a good linear relationship with HClO/ClO− concentration in the range of 0–30.0 μM, and the detection limit was as low as 37.8 nM. In addition, convenient on-site rapid (∼1 s) visual identification of aqueous HClO/ClO− was also realized via Py-DA-based paper strips. Furthermore, Py-DA with good photo-stability and low cytotoxicity has been successfully applied for HClO/ClO− imaging in human cervical cancer cells (HeLa). The results of this study provide new ideas for further investigation of the physiological and pathological effects of HClO.
Active materials are of great interest to a broad spectrum of scientists, including those in physics, biology, materials science, engineering, and biomedical engineering. Learning how to control active materials in a programmable manner could open opportunities for designing smart materials and micromachines. This review presents advances to program out-of-equilibrium active materials, including living bacteria, inanimate colloids, and soft active materials such as stimuli-responsive liquid crystal (LC) polymer networks. The collective dynamics of microscopic bacteria can be controlled to form vortices and polar jets by using topological defects and patterns in LC. Similarly, the collective transport and programmable reconfigurations of microscopic colloids are achieved through the manipulation of LC defect structures. Additionally, the nanoscale orientational order in topological patterns can be incorporated into LC polymer networks to control the complex patterning of nanofiber structures. Furthermore, when the molecular orientations of topological defects are combined with the geometrical shapes of liquid crystal elastomer kirigami, macroscopic morphing behaviors can be programmed by manipulating the interplay between topological profiles and kirigami shapes. Hence, the programmable active materials discussed in this review encompass topics ranging from the collective dynamics of microscopically inanimate and living objects to the macroscopic shape morphing of polymeric constructs. Finally, this review provides perspectives on future opportunities and will inspire advancements in fields such as responsive materials, soft robotics, and tissue engineering.
In the era of precision medicine, photopharmacology that employs molecular photoswitches offers unique opportunities to control the action of bioactive molecules with high spatiotemporal resolution, while reducing drug side effects, systemic toxicity and the emergence of resistance. Over the past two decades, the field of photopharmacology has witnessed great achievements in treating with blindness, cancer, diabetes, antibiotic resistance, and to name but a few. Several challenges remain, however, in particular the fact that most photopharmacological agents trigger their activity by Ultraviolet light, which is damaging to normal cells and has poor tissue permeability. Visible light-activated photopharmacological agents are hence highly desirable and have captured keen recent research interest. This review highlights strategies for the synthesis of visible light-responsive azobenzenes (ABs) and their applications in the emerging photopharmacology. Such visible light-activated photoswitchable drugs tremendously extend the scope of photopharmacology for future in vivo applications. Furthermore, we identify the current challenges and discuss future opportunities for rational design in photopharmacology that switches at a higher wavelength. We hope to inspire further research into the photochemistry of novel photopharmacological agents based on ABs or other photoswitches, which are triggered by the excitation light in “phototherapeutic window” of 650–900 nm, ultimately enabling full realization of these “smart” drugs in the clinical practice.
Windows are considered to be a major contributor to energy consumption in buildings. Smart windows, as a replacement for traditional windows, can reversibly regulate the transmittance of sunlight, enabling indoor thermal regulation and promising to reduce building energy consumption, thus attracting increasing attention. Especially, the smart windows based on photochromic (PC) or electrochromic (EC) materials have been widely researched due to zero energy input and potential for seasonal adaptability of PC smart windows, as well as the unique active adjustment mode of EC smart windows. These smart windows hold promising application prospects in the field of thermal regulation of future low energy-consumption buildings. However, issues such as the difficulty in scaling up EC smart windows, the slow response time of PC smart windows, and the poor cycling stability and durability common to both EC and PC smart windows limit their development in the field of building thermal regulation. Focusing on the important progresses and challenges of these smart windows based on PC or EC materials, we systematically review the typical researches reported in recent years. This review covers the evaluation parameters of thermal regulation performance, innovative mechanisms, optical regulation optimization methods, and developing status of the smart windows based on PC or EC materials. Moreover, we also discuss the existing issues with the current smart windows and propose targeted improving suggestions. Hopefully, this review can promote the further development of the smart thermal regulation technologies with PC or EC windows.
Harnessing nanoscale molecular structural changes to achieve precise control over macroscopic devices represents an emerging and effective strategy. One promising approach involves the introduction of light-driven chiral dopants into liquid crystals (LCs), enabling the fine-tuned modulation of the helical superstructures in cholesteric liquid crystals (CLCs) via photoisomerization. This strategy opens up exciting possibilities for the development of innovative photo-responsive devices with dynamic functionalities. This review focuses on the most common light-driven chiral dopants used in LCs, including azobenzene, diarylethene, α-cyanostilbene and overcrowded alkene. The chemical design principles of these four types of chiral switches are highlighted, along with their abilities to induce pitch changes and helical inversion in CLCs. Finally, the applications of light-driven chiral dopants in controlling helical superstructures are showcased, particularly in display technologies, anti-counterfeiting, optical modulation and 3D droplet manipulation. It is hoped that this review provides valuable insights and guidances for the development of novel light-driven chiral dopants and the advancement of soft matter material applications.
Lasers generate coherent, collimated, intense and monochromatic radiation at optical wavelengths with precise spatiotemporal control. This unique combination of attractive properties is stimulating the design of optical cavities and gain materials to replicate the functions of lasers at the microscale with the ultimate goal of developing miniaturized light sources for biomedical and information technologies. Borrowing from the fundamental principles of macroscopic dye lasers, microscopic analogs able to sustain light amplification by stimulated emission of radiation from fluorescent dyes have, indeed, become a reality. Microdroplets of dye solutions are their simplest implementation. Large numbers of dye-doped microdroplets with identical shapes and sizes can be produced efficiently, inexpensively and rapidly to permit the convenient investigation of their properties with statistical confidence. In fact, a solid understanding of the geometrical, optical and photophysical factors regulating the ability of a single dye-doped microdroplet to produce laser emission has already been developed. As a result of these seminal studies, methods to control the lasing spectrum of a dye-doped microdroplet with external stimulations are now available, providing access potentially to miniaturized lasers with tunable emission. In particular, mechanically-, optically- and thermally-induced deformations in the shape of a microdroplet, changes in its size or modifications in the absorption coefficient of its constituent components are all viable strategies to manipulate lasing. The latter mechanisms rely on structural and/or electronic modifications of the dyes in the microdroplet interior to regulate the fine balance between optical gain and absorption losses responsible for lasing and are the primary focus of this review.