Synthesis, light-controlled antibacterial and anti-tumor activities of Ginkgo biloba leaves polyprenols-based polypyridine metal complexes.

In this study, Ginkgo biloba leave polyprenols (GBP) and polypyridine metal complex were individually utilized as functional ligand and main ligand, four kinds of novel GBP-based polypyridine metal complexes were successfully synthesized and their cell absorption capacity, light-dark stability, photodissociation efficiency, ROS production capacity, light-controlled antibacterial and anti-tumor activities as well as mechanisms were systematically investigated by ultraviolet visible spectrophotometer (UV-vis), confocal laser scanning microscope (CLSM), gel electrophoresis (GE), scanning electron microscope (SEM), oxford cup method, MTT method etc. The lipid water distribution coefficients of complex 1, 2 and 4 were all within the range of 0∼3, demonstrating their better cell absorption capacity and more competitive bioavailability potentiality compared with GBP. All of the synthesized complexes possessed excellent stability in a dark environment, and could conduct ligand dissociation under the condition of visible light irradiation except complex 1. In which, complex 2 and complex 4 were able to achieve degradation rates of 37.9 % and 54.4 % within 5 min, separately. In addition, complex 2 and complex 4 exhibited superior inhibitory activities on the HN-3 tumor cells on account of their stronger ROS production capacity. Moreover, the constricted expression of BCL-2 and NF-kB p-p65, especially the promoted expression of BAX may be one of the root cause. The four synthesized complexes had preferable inhibition effects against S. aureus under the condition of visible light irradiation in contrast to darkness, in which complex 4 was the best and its MIC and MBC values were 6.25 and 12.5 µg/mL, respectively. The antibacterial mechanism of the complex 4 may be in relation to the synergistic effect of multiple factors, including leakage of bacterial inclusion, change of cell membrane permeability and disruption of cell wall etc. All of the above generalized researches will pave a way for the high-value development and application of GBP-based functional products.

Photo-programmable hydrogel iontronics for electrically and chromatically rewritable circuits.

Hydrogel-based iontronics is emerging as a promising frontier in healthcare and human-machine interfacing (HMI), offering excellent compatibility with biological systems in terms of electrical, chemical, and mechanical properties. However, conventional hydrogel systems have limitations in dynamically regulating their electrical and optical properties, which restricts their use in adaptive electronics and responsive interfaces. In this study, we present a new hydrogel system with UV photochemistry-induced reversible conductivity, enabling reversible changes in conductivity. Unlike typical photo-responsive hydrogels that revert to their original states upon removal of the light source, the new hydrogel can maintain its activated states without continuous light exposure, facilitating practical applications. By leveraging the photobase triphenylmethane leucohydroxide and photoacid n-nitrobenzaldehyde, we achieve a significant increase in photo-induced conductivity compared to existing photo-ionic hydrogels. Combining the effective photo-induced conductivity and the accompanied photochromatic effect, we demonstrate a full hydrogel-based stylus pad capable of tracking motion and strokes, and a soft calculator keypad with programmable conductivity and imprinted patterns. These advancements underscore the importance of actively controlling localized conductivity and processing light inputs in hydrogels, exhibiting their potential for diverse applications in bioelectronics and HMI.

Advances in Light-Responsive Smart Multifunctional Nanofibers: Implications for Targeted Drug Delivery and Cancer Therapy.

Over the last decade, scientists have shifted their focus to the development of smart carriers for the delivery of chemotherapeutics in order to overcome the problems associated with traditional chemotherapy, such as poor aqueous solubility and bioavailability, low selectivity and targeting specificity, off-target drug side effects, and damage to surrounding healthy tissues. Nanofiber-based drug delivery systems have recently emerged as a promising drug delivery system in cancer therapy owing to their unique structural and functional properties, including tunable interconnected porosity, a high surface-to-volume ratio associated with high entrapment efficiency and drug loading capacity, and high mass transport properties, which allow for controlled and targeted drug delivery. In addition, they are biocompatible, biodegradable, and capable of surface functionalization, allowing for target-specific delivery and drug release. One of the most common fiber production methods is electrospinning, even though the relatively two-dimensional (2D) tightly packed fiber structures and low production rates have limited its performance. Forcespinning is an alternative spinning technology that generates high-throughput, continuous polymeric nanofibers with 3D structures. Unlike electrospinning, forcespinning generates fibers by centrifugal forces rather than electrostatic forces, resulting in significantly higher fiber production. The functionalization of nanocarriers on nanofibers can result in smart nanofibers with anticancer capabilities that can be activated by external stimuli, such as light. This review addresses current trends and potential applications of light-responsive and dual-stimuli-responsive electro- and forcespun smart nanofibers in cancer therapy, with a particular emphasis on functionalizing nanofiber surfaces and developing nano-in-nanofiber emerging delivery systems for dual-controlled drug release and high-precision tumor targeting. In addition, the progress and prospective diagnostic and therapeutic applications of light-responsive and dual-stimuli-responsive smart nanofibers are discussed in the context of combination cancer therapy.

An "in control" hyaluronic acid nanogel with light-cleavable for rational use of antibiotics.

The consequences caused by bacterial resistance are becoming more and more serious. The rate of antibiotic development is far behind the rate of bacterial resistance, so it is urgent to develop a new drug system. In this study, photoresponsive nanogels based on hyaluronic acid were prepared and loaded with ciprofloxacin as a model molecule. The results showed that the nanogels had the advantages of high stability and good cytocompatibility. The inhibition effect of drug-loaded nanogels after light irradiation on the growth of Staphylococcus aureus and Salmonella typhimurium was significantly better than that before light irradiation, and ciprofloxacin could be released on demand and in control. This strategy is of great significance to reduce the unnecessary use of antibiotics and weaken bacterial resistance.

Designing and synthesis of perovskite nanocrystals: a promising wide-spectrum solar light-responsive photocatalyst and lead ion sensor.

Perovskites are an emerging material with a variety of applications, ranging from their solar light conversion capability to their sensing efficiency. In current study, perovskite nanocrystals (PNCs) were designed using theoretical density functional theory (DFT) analysis. Moreover, the theoretically designed PNCs were fabricated and confirmed by various characterization techniques. The calculated optical bandgap from UV-Vis and fluorescence spectra were 2.15 and 2.05 eV, respectively. The average crystallite size of PNCs calculated from Scherrer equation was 15.18 nm, and point of zero charge (PZC) was obtained at pH 8. The maximum eosin B (EB) removal efficiency by PNCs was 99.56% at optimized conditions following first-order kinetics with 0.98 R2 value. The goodness of the response surface methodology (RSM) model was confirmed from analysis of variance (ANOVA), with the experimental F value (named after Ronald Fisher) of 194.66 being greater than the critical F value F0.05, 14, 14 = 2.48 and a lack of fit value of 0.0587. The Stern-Volmer equation with a larger Ksv value of 1.303710 × 10 6 for Pb2+ suggests its greater sensitivity for Pb2+ among the different metals tested.

Rice CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1-LIKE interacts with OsCRY2 and promotes flowering by upregulating Early heading date 1.

Flowering time is a crucial adaptive response to seasonal variation in plants and is regulated by environmental cues such as photoperiod and temperature. In this study, we demonstrated the regulatory function of rice CRYPTOCHROME-INTERACTING BASIC HELIX-LOOP-HELIX 1-LIKE (OsCIBL1) in flowering time. Overexpression of OsCIB1L promoted flowering, whereas the oscib1l knockout mutation did not alter flowering time independent of photoperiodic conditions. Cryptochromes (CRYs) are blue light photoreceptors that enable plants to sense photoperiodic changes. OsCIBL1 interacted with OsCRY2, a member of the rice CRY family (OsCRY1a, OsCRY1b, and OsCRY2), and bound to the Early heading date 1 (Ehd1) promoter, activating the rice-specific Ehd1-Heading date 3a/RICE FLOWERING LOCUS T 1 pathway for flowering induction. Dual-luciferase reporter assays showed that the OsCIBL1-OsCRY2 complex required blue light to induce Ehd1 transcription. Natural alleles resulting from nonsynonymous single nucleotide polymorphisms in OsCIB1L and OsCRY2 may contribute to the adaptive expansion of rice cultivation areas. These results expand our understanding of the molecular mechanisms controlling rice flowering and highlight the importance of blue light-responsive genes in the geographic distribution of rice.

Near-infrared light-responsive hydrogels for on-demand dual delivery of proangiogenic growth factors.

Achieving precise spatiotemporal control over the release of proangiogenic factors is crucial for vasculogenesis, the process of de novo blood vessel formation. Although various strategies have been explored, there is still a need to develop cell-laden biomaterials with finely controlled release of proangiogenic factors at specific locations and time points. We report on the developed of a near-infrared (NIR) light-responsive collagen hydrogel comprised of gold nanorods (GNRs)-conjugated liposomes containing proangiogenic growth factors (GFs). We demonstrated that this system enables on-demand dual delivery of GFs at specific sites and over selected time intervals. Liposomes were strategically formulated to encapsulate either platelet-derived growth factor (PDGF) or vascular endothelial growth factor (VEGF), each conjugated to gold nanorods (GNRs) with distinct geometries and surface plasmon resonances at 710 nm (GNR710) and 1064 nm (GNR1064), respectively. Using near infrared (NIR) irradiation and two-photon (2P) luminescence imaging, we successfully demonstrated the independent release of PDGF from GNR710 conjugated liposomes and VEGF from GNR1064-conjugated liposomes. Our imaging data revealed rapid release kinetics, with localized PDGF released in approximately 4 min and VEGF in just 1 and a half minutes following NIR laser irradiation. Importantly, we demonstrated that the release of each GF could be independently triggered using NIR irradiation with the other GF formulation remaining retained within the liposomes. This light-responsive collagen hydrogels holds promise for various applications in regenerative medicine where the establishment of a guided vascular network is essential for the survival and integration of engineered tissues. STATEMENT OF SIGNIFICANCE: In this study, we have developed a light-responsive system with gold nanorods (GNRs)-conjugated liposomes in a collagen hydrogel, enabling precise dual delivery of proangiogenic growth factors (GFs) at specific locations and timepoints. Liposomes, containing platelet-derived growth factor (PDGF) or vascular endothelial growth factor (VEGF), release independently under near- infrared irradiation. This approach allows external activation of desired GF release, ensuring high cell viability. Each GF can be triggered independently, retaining the other within the liposomes. Beyond its application in establishing functional vascular networks, this dual delivery system holds promise as a universal platform for delivering various combinations of two or more GFs.

Active control of pharmacokinetics using light-responsive polymer-drug conjugates for boron neutron capture therapy.

In boron neutron capture therapy (BNCT), boron drugs should exhibit high intratumoral boron concentrations during neutron irradiation, while being cleared from the blood and normal organs. However, it is usually challenging to achieve such tumor accumulation and quick clearance simultaneously in a temporally controlled manner. Here, we developed a polymer-drug conjugate that can actively control the clearance of the drugs from the blood. This polymer-drug conjugate is based on a biocompatible polymer that passively accumulates in tumors. Its side chains were conjugated with the low-molecular-weight boron drugs, which are immediately excreted by the kidneys, via photolabile linkers. In a murine subcutaneous tumor model, the polymer-drug conjugate could accumulate in the tumor with the high boron concentration ratio of the tumor to the surrounding normal tissue (∼10) after intravenous injection while a considerable amount remained in the bloodstream as well. Photoirradiation to blood vessels through the skin surface cleaved the linker to release the boron drug in the blood, allowing for its rapid clearance from the bloodstream. Meanwhile, the boron concentration in the tumor which was not photoirradiated could be maintained high, permitting strong BNCT effects. In clinical BNCT, the dose of thermal neutrons to solid tumors is determined by the maximum radiation exposure to normal organs. Thus, our polymer-drug conjugate may enable us to increase the therapeutic radiation dose to tumors in such a practical situation.

A MXene Hydrogel-Based Versatile Microrobot for Controllable Water Pollution Management.

The urgent demand for addressing dye contaminants in water necessitates the development of microrobots that exhibit remote navigation, rapid removal, and molecular identification capabilities. The progress of microrobot development is currently hindered by the scarcity of multifunctional materials. In this study, a plasmonic MXene hydrogel (PM-Gel) is synthesized by combining bimetallic nanocubes and Ti3C2Tx MXene through the rapid gelation of degradable alginate. The hydrogel can efficiently adsorb over 60% of dye contaminants within 2 min, ultimately achieving a removal rate of >90%. Meanwhile, the hydrogel exhibits excellent sensitivity in surface enhanced Raman scattering (SERS) detection, with a limit of detection (LOD) as low as 3.76 am. The properties of the plasmonic hydrogel can be further adjusted for various applications. As a proof-of-concept experiment, thermosensitive polymers and superparamagnetic particles are successfully integrated into this hydrogel to construct a versatile, light-responsive microrobot for dye contaminants. With magnetic and optical actuation, the robot can remotely sample, identify, and remove pollutants in maze-like channels. Moreover, light-driven hydrophilic-hydrophobic switch of the microrobots through photothermal effect can further enhance the adsorption capacity and reduced the dye residue by up to 58%. These findings indicate of a broad application potential in complex real-world environments.

Visible Light-Gating Responsive Nanochannel for Controlled Release of the Fungicide.

Fungicides have been widely used to protect crops from the disease of pythium aphanidermatum (PA). However, excessive use of synthetic fungicides can lead to fungal pathogens developing microbicide resistance. Recently, biomimetic nano-delivery systems have been used for controlled release, reducing the overuse of fungicides, and thereby protecting the environment. In this paper, inspired by chloroplast membranes, visible light biomimetic channels are constructed by using retinal, the main component of green pigment on chloroplasts in plants, which can achieve the precise controlled release of the model fungicide methylene blue (MB). The experimental results show that the biomimetic channels have good circularity after and before light conditions. In addition, it is also found that the release of MB in visible light by the retinal-modified channels is 8.78 µmol·m-2·h-1, which is four times higher than that in the before light conditions. Furthermore, MB, a bactericide drug model released under visible light, can effectively inhibit the growth of PA, reaching a 97% inhibition effect. The biomimetic nanochannels can realize the controlled release of the fungicide MB, which provides a new way for the treatment of PA on the leaves surface of cucumber, further expanding the application field of biomimetic nanomembrane carrier materials.

Vacuum Thermoforming of Optically Switchable Liquid Crystalline Elastomer Spherical Actuators.

Liquid crystal elastomer (LCE) actuators are generally limited in shape, size, and quantity by the need for aligning via stretching and fixing via photopolymerizing. A thermoplastic LCE is presented that may be vacuum thermoformed into centimeter-sized hemispheres. The scalable industrial process induces LCE alignment without requiring postfixing. The hemispheres display remarkable properties, actuating with strains around 20% and transitioning from opaque and scattering to highly translucent upon heating: both the physical and optical effects are fully reversible. Simulations reveal the LCE experiences biaxial strains during processing, the magnitude varying as a function of location on the hemisphere: the resulting alignment describing the hemisphere actuation well. The thermoplastic LCE hemispheres may be combined to form complete spheres by simply heating the joint. The hemisphere can also be physically deformed into a ball which can then unfold back into the hemisphere again. By doping the hemispheres with photoswitches, fluorescent or photothermal dyes, devices are formed for light collection and redistribution, addressable water containers that may pour at will, and light-responsive surfing devices. This is the first example of an LCE amenable to high-volume industrial vacuum thermoforming which may lead to intricate 3D-shaped actuators with new functional properties.

Shape Memory Polyurethane Composite With Fast Response to Near-Infrared Light Based on Tannic Acid-Iron and Dynamic Phenol-Carbamate Network.

Intelligent materials derived from green and renewable bio-based materials garner widespread attention recently. Herein, shape memory polyurethane composite (PUTA/Fe) with fast response to near-infrared (NIR) light is successfully prepared by introducing Fe3+ into the tannic acid-based polyurethane (PUTA) matrix through coordination between Fe3+ and tannic acid. The results show that the excellent NIR light response ability is due to the even distribution of Fe3+ filler with good photo-thermal conversion ability. With the increase of Fe3+ content, the NIR light response shape recovery rate of PUTA/Fe composite films is significantly improved, and the shape recovery time is reduced from over 60 s to 40 s. In addition, the mechanical properties of PUTA/Fe composite film are also improved. Importantly, owing to the dynamic phenol-carbamate network within the polymer matrix, the PUTA/Fe composite film can reshape its permanent shape through topological rearrangement and show its good NIR light response shape memory performance. Therefore, PUTA/Fe composites with high content of bio-based material (TA content of 15.1-19.4%) demonstrate the shape memory characteristics of fast response to NIR light; so, it will have great potential in the application of new intelligent materials including efficient and environmentally friendly smart photothermal responder.

Enhanced UV protection in silk fibroin based electrospun fabrics realized via orientation induced high efficiency of azobenzene isomerization.

Due to the poor UV protection capability, natural silk fabrics not only suffer from easy damage by sunshine but also induce possible sunburn in the human body. Efficient azobenzene isomerization and enhanced UV shielding are realized by replacing the natural silk with natural protein silk fibroin (SF) and electrospinning together with light-responsive copolymer P(MEO2-co-OEG300-co-AHMA). Compared to a solution cast film, the absorption peak intensity at 355 nm is 60 % higher in UV-Vis spectra of the electropsun SF/P(MEO2-co-OEG300-co-AHMA) fabrics. This improvement is related to the highly oriented chains, inducing more space and higher efficiency for azobenzene isomerization. Only exposure to visible light for 20 min, the absorption peak corresponding to the trans- state at 355 nm recovers to 92.5 % in the electrospun fabrics, which is at least 100 % faster than that in the solution cast film (50 min). It is related to the zip effect of the isomerization in the oriented chain structure. Thus, not only the absorption of UV radiation, but also the isomerization rate is enhanced. Based on these unique absorption and recovery capabilities, the SF based electrospun fabrics can be used to replace the natural silk fabrics for UV shielding in summer, especially for cyclic use.

Light-Responsive Shape- and Color-Changing Block Copolymer Particles with Fast Switching Speed.

Polymer particles capable of dynamic shape changes in response to light have received substantial attention in the development of intelligent multifunctional materials. In this study, we develop a light-responsive block copolymer (BCP) particle system that exhibits fast and reversible shape and color transitions. The key molecular design is the integration of spiropyran photoacid (SPPA) molecules into the BCP particle system, which enables fast and dynamic transformations of polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) particles in response to light. The SPPA photoisomerization, induced by 420 nm light irradiation, lowers the pH of the aqueous surroundings from 5.5 to 3.3. The protonated P4VP block substantially increases in domain size from 14 to 39 nm, resulting in significant elongation of the BCP particles (i.e., an increase in the aspect ratio (AR) of the particles from 1.8 to 3.4). Moreover, SPPA adsorbed onto the P4VP surface induces significant changes in the luminescent properties of the BCP particles via photoisomerization of SPPA. Notably, the BCP particles undergo fast, dynamic shape and color transitions within a period of 10 min, maintaining high reversibility over multiple light exposures. Functional dyes are selectively incorporated into different domains of the light-responsive BCP particles to achieve different ranges of color responses. Thus, this study showcases a light-responsive hydrogel display capable of reversible and multicolor photopatterning.

Light-Responsive Materials in Droplet Manipulation for Biochemical Applications.

Miniaturized droplets, characterized by well-controlled microenvironments and capability for parallel processing, have significantly advanced the studies on enzymatic evolution, molecular diagnostics, and single-cell analysis. However, manipulation of small-sized droplets, including moving, merging, and trapping of the targeted droplets for complex biochemical assays and subsequent analysis, is not trivial and remains technically demanding. Among various techniques, light-driven methods stand out as a promising candidate for droplet manipulation in a facile and flexible manner, given the features of contactless interaction, high spatiotemporal resolution, and biocompatibility. This review therefore compiles an in-depth discussion of the governing mechanisms underpinning light-driven droplet manipulation. Besides, light-responsive materials, representing the core of light-matter interaction and the key character converting light into different forms of energy, are particularly assessed in this review. Recent advancements in light-responsive materials and the most notable applications are comprehensively archived and evaluated. Continuous innovations and rational engineering of light-responsive materials are expected to propel the development of light-driven droplet manipulation, equip droplets with enhanced functionality, and broaden the applications of droplets for biochemical studies and routine biochemical investigations.

3D-printed near-infrared-light-responsive on-demand drug-delivery scaffold for bone regeneration.

Although several bioactive 3D-printed bone scaffolds loaded with multiple kinds of biomolecules for enhanced bone regeneration have been recently developed, the manipulation of on-demand release profiles of different biomolecules during bone regeneration remains challenging. Herein, a 3D-printed dual-drug-loaded biomimetic scaffold to regulate the host stem cell recruitment and osteogenic differentiation in a two-stage process for bone regeneration was successfully fabricated. First, a chemotactic small-molecule drug, namely, simvastatin (SIM) was directly incorporated into the hydroxyapatite/collagen bioink for printing and could be rapidly released during the early stage of bone regeneration. Further, near-infrared (NIR)-light-responsive polydopamine-coated hydroxyapatite nanoparticles were designed to deliver the osteogenic drug, i.e., pargyline (PGL) in a controllable manner. Together, our scaffold displayed an on-demand sequential release of those two drugs and could optimize their therapeutic effects to align with the stem cell recruitment and osteoblastic differentiation, thereby promoting bone regeneration. The results confirmed the suitable mechanical strength, high photothermal conversion efficiency, good biocompatibility of our scaffold. The scaffold loaded with SIM could efficiently accelerate the migration of stem cells. In addition, the scaffold with on-demand sequential release promoted alkaline phosphatase (ALP) activity, significantly upregulated gene expression levels of osteogenesis-related markers, and enhanced new-bone-formation capabilities in rabbit cranial defect models. Altogether, this scaffold not only offers a promising strategy to control the behavior of stem cells during bone regeneration but also provides an efficient strategy for controllable sequential release of different biomolecule in bone tissue engineering.

Light-Responsive and Dual-Targeting Liposomes: From Mechanisms to Targeting Strategies.

In recent years, nanocarriers have played an ever-increasing role in clinical and biomedical applications owing to their unique physicochemical properties and surface functionalities. Lately, much effort has been directed towards the development of smart, stimuli-responsive nanocarriers that are capable of releasing their cargos in response to specific stimuli. These intelligent-responsive nanocarriers can be further surface-functionalized so as to achieve active tumor targeting in a sequential manner, which can be simply modulated by the stimuli. By applying this methodological approach, these intelligent-responsive nanocarriers can be directed to different target-specific organs, tissues, or cells and exhibit on-demand controlled drug release that may enhance therapeutic effectiveness and reduce systemic toxicity. Light, an external stimulus, is one of the most promising triggers for use in nanomedicine to stimulate on-demand drug release from nanocarriers. Light-triggered drug release can be achieved through light irradiation at different wavelengths, either in the UV, visible, or even NIR region, depending on the photophysical properties of the photo-responsive molecule embedded in the nanocarrier system, the structural characteristics, and the material composition of the nanocarrier system. In this review, we highlighted the emerging functional role of light in nanocarriers, with an emphasis on light-responsive liposomes and dual-targeted stimuli-responsive liposomes. Moreover, we provided the most up-to-date photo-triggered targeting strategies and mechanisms of light-triggered drug release from liposomes and NIR-responsive nanocarriers. Lastly, we addressed the current challenges, advances, and future perspectives for the deployment of light-responsive liposomes in targeted drug delivery and therapy.

NIR-Light-Triggered Mild-Temperature Hyperthermia to Overcome the Cascade Cisplatin Resistance for Improved Resistant Tumor Therapy.

Currently, cisplatin resistance has been recognized as a multistep cascade process for its clinical chemotherapy failure. Hitherto, it remains challenging to develop a feasible and promising strategy to overcome the cascade drug resistance (CDR) issue for achieving fundamentally improved chemotherapeutic efficacy. Herein, a novel self-assembled nanoagent is proposed, which is constructed by Pt(IV) prodrug, cyanine dye (cypate), and gadolinium ion (Gd3+), for systematically conquering the cisplatin resistance by employing near-infrared (NIR) light activated mild-temperature hyperthermia in tumor targets. The proposed nanoagents exhibit high photostability, GSH/H+-responsive dissociation, preferable photothermal conversion, and enhanced cellular uptake performance. In particular, upon 785-nm NIR light irradiation, the generated mild temperature of ≈ 43 °C overtly improves the cell membrane permeability and drug uptake, accelerates the disruption of intracellular redox balance, and apparently enhances the formation of Pt-DNA adducts, thereby effectively overcoming the CDR issue and achieves highly improved therapeutic efficacy for cisplatin-resistant tumor ablation.

Colorimetric detection of alkaline phosphatase based on the off-on effect of light-responsive oxidase mimicking activity of covalent organic framework (Cu-TpBpy-COF) under near-neutral condition.

A colorimetric strategy has been developed for the detection of alkaline phosphatase (ALP) activity based on the off-on effect of the catalytic activity of light-responsive oxidase mimics covalent organic framework (Cu-TpBpy-COF) in near-neutral condition. Cu-TpBpy-COF can effectively catalyze the oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine (TMB) by oxygen to form a blue oxidized product (oxTMB) with an absorption peak at 652 nm. Cu2+ is the active center of Cu-TpBpy-COF and pyrophosphate (PPi) can form a complex with Cu2+ to weaken the catalytic activity of Cu-TpBpy-COF. In the presence of ALP, PPi is hydrolyzed into orthophosphates (Pi) with low affinity to Cu2+, thus resulting in absorbance restoration. The absorbance at 652 nm is related to ALP activity in the linear range 10-150 U·L-1 with a detection limit of 7.17 U·L-1. The recoveries of ALP in serum samples are in the range 94.7~107.0% with relative standard deviations (RSD) lower than 5%. The decisive role of Cu2+ on the enhancing catalytic activities of Cu-TpBpy-COF in neutral condition was verified by TpBpy-COF and TpBD-COF as controls, in which the main difference between them is that TpBpy-COF contains pyridine nitrogen. Upon Cu2+ modification, Cu-TpBpy-COF has better catalytic activity than TpBpy-COF in a broader pH range because of the in situ generation of Cu+ under irradiation.

NIR-promoted ferrous ion regeneration enhances ferroptosis for glioblastoma treatment.

Ferroptosis, a unique iron-dependent mode of cell death characterized by lipid peroxide accumulation, holds significant potential for the treatment of glioblastoma (GBM). However, the effectiveness of ferroptosis is hindered by the limited intracellular ferrous ions (Fe2+) and hydrogen peroxide (H2O2). In this study, a novel near-infrared (NIR)-light-responsive nanoplatform (ApoE-UMSNs-GOx/SRF) based on upconversion nanoparticles (UCNPs) was developed. A layer of mesoporous silica and a lipid bilayer were coated on UCNPs sequentially and loaded with glucose oxidase (GOx) and sorafenib, respectively. Further attachment of the ApoE peptide endowed the nanoplatform with BBB penetration and GBM targeting capabilities. Our results revealed that ApoE-UMSNs-GOx/SRF could efficiently accumulated in the orthotopic GBM and induce amplified ferroptosis when combining with NIR irradiation. The UCNPs mediated the photoreduction of Fe3+ to Fe2+ by converting NIR to UV light, and excess H2O2 was produced by the reaction of glucose with the loaded GOx. These processes greatly promoted the production of ROS, which together with inhibition of system Xc- by the loaded sorafenib, leading to enhanced accumulation of lipid peroxides and significantly improved the antiglioma effect both in vitro and in vivo. Our strategy has the potential to enhance the effectiveness of ferroptosis as a therapeutic approach for GBM.