Photodynamic Properties Research Articles

A near-infrared-activated heterostructure endowed nerve scaffold with electrical stimulation and antibacterial performance

The weak tissue inducibility and easy implantation infection are still challenges confronted to tissue scaffold. Bismuth sulfide (Bi2S3) possessed favorable photoelectric, photothermal, and photodynamic properties not only enabling to response near-infrared light to generate electrical signals to promote nerve growth but also simultaneously produces reactive oxygen species (ROS) and heat to kill bacteria, which emerges as a promising alternative. However, the easy recombination of electron-hole weakens its photocurrent and ROS generation. Herein, Bi2S3/Ag3PO4 heterostructures are prepared by in situ growing Ag3PO4 on Bi2S3 and then mixed with poly-L-lactic acid powder to fabricate scaffolds by selective laser sintering. Due to the different Fermi levels of Bi2S3 and Ag3PO4, the photogenerated electrons of Bi2S3 transferred to the conduction band of Ag3PO4. Meanwhile, the heterojunction impeded the backflow of electrons, which efficiently achieved electron-hole pair separation. Results indicate that the photocurrent and ROS generated by the scaffold was enhanced. The improved photocurrent effectively induces stem cells to differentiate into nerve cells through up-regulating Ca2+ concentration and neural-specific markers Nestin expression. The produced ROS, photothermal, and Ag+ can synergistically kill bacteria. Ultimately, the scaffold exhibited excellent antimicrobial efficiency with 90.59 % and 91.45 % against E. coli and S. aureus, respectively. This strategy provides a new perspective to realize the integrated preparation of nerve scaffolds with electrical stimulation and antibacterial performance.

The photodynamic activity properties of a series of structurally analogous tetraarylporphyrin, chlorin and N-confused porphyrin dyes and their Sn(IV) complexes

A series of tetraarylporphyrin, -chlorin and N-confused porphyrin dyes with 4‑methoxy‑meso-aryl rings (1-Por, 1-Chl and 1-NCP) and their Sn(IV) complexes (1-SnPor, 1-SnChl and 1-SnNCP) have been synthesized and characterized. The heavy atom effect of the Sn(IV) ion results in relatively high singlet oxygen quantum yield values of 0.67, 0.71 and 0.85 for 1-SnPor, 1-SnChl and 1-SnNCP, respectively. The photodynamic activities of 1-Por, 1-Chl, 1-NCP, 1-SnPor, 1-SnChl and 1-SnNCP were determined against MCF-7 breast cancer cells through illumination with Thorlabs 625 or 660 nm (240 or 280 mW.cm−2) light emitting diodes (LEDs) for 20 min. The IC50 values for 1-SnChl and 1-SnNCP lie between 1.4 − 6.1 and 1.6 − 4.8 µM upon photoirradiation with the 660 and 625 nm LEDs, respectively, while higher values of >10 µM were obtained for 1-SnPor and the free base dyes. In a similar manner, 1-SnChl and 1-SnNCP were found to also have significantly higher photodynamic antimicrobial activity against planktonic Gram-(+) Staphylococcus aureus and Gram-(−) Escherichia coli bacteria than the other dyes studied. Upon illumination with Thorlabs 625 and 660 nm LEDs for 75 min, Log10 reduction values of 7.62 and > 2.40−3.69 were obtained with 1 and 5 µM solutions, respectively.

Carbon dot-based antimicrobial photosensitizer: Synthesis, characterization and antimicrobial performance against food borne pathogens

In this study, quasi-spherical carbon dots (CDs) with a white appearance were synthesized from acetate and zinc (Z). The size of the CDs was less than 10 nm and −11.4 mV zeta potential. At concentrations lower than 5 mg/mL, the Z-CDs showed no cytotoxicity in L929 fibroblasts. The antimicrobial activity of Z-CDs was dose-dependent on both Gram-positive (Listeria monocytogenes) and Gram-negative (Salmonella Typhimurium) bacteria in antimicrobial assays. Furthermore, observations from SEM imaging confirmed this activity. The photodynamic properties of the photosensitizer Z-CDs were examined with a focus on Z-CDs concentration and irradiation [i.e., time (0–120 min), temperature (4 and 25 °C), and LED lamps (360 and 420 nm wavelength)]. It was evident that L. monocytogenes was susceptible to photodynamic treatment at 25 °C when both wavelengths were utilized. The photodynamic properties of Z-CDs were influenced largely by temperature, followed by wavelength and Z-CDs concentration parameters. Remarkably, the bacterial cell membranes were significantly destroyed by Z-CDs and photodynamic treatments. These multifunctional Z-CDs are highly appealing candidates for food and biomedical applications owing to their favorable characteristics; such as low toxicity, photosensitizing properties, and appearance.

Photodynamic antibacterial activity of oxidase-like nanozyme based on long-lived room-temperature phosphorescent carbon dots

In this study, a novel long-lived room-temperature phosphorescent (RTP) carbon dots (P-CDs) with the properties of ultraviolet/visible (UV/Vis) light photoresponsive oxidase-like nanozyme were synthesized from diethylenetriaminepentaacetic acid and through a one-step hydrothermal method. P-CDs were used as a light-driven oxidative-like enzyme for antimicrobial studies. The results showed that under UV/Vis light irradiation, P-CDs could efficiently convert O2 into 1O2, and the strong oxidizing property of 1O2 greatly enhanced the growth inhibition of P-CDs on Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli). Meanwhile, P-CDs exhibited good photodynamic antifungal properties against Botrytis cinerea (B. cinerea). Then the P-CDs were made into P-CDs/PVA films, which effectively prolonged the preservation period of fruits under photodynamic antibacterial action. The good biocompatibility and efficient photosensitive oxygen activation can make P-CDs a more practically useful oxidase-like nanozyme.

Low-Temperature Photothermal Therapy Platform Based on Pd Nanozyme-Modified Hydrogenated TiO2.

In photothermal treatments (PTTs), normal tissues around cancerous tumors get injured by excessive heat, whereas damaged cancer cells are easily restored by stress-induced heat shock proteins (HSPs) at low temperatures. Therefore, to achieve a unique tumor microenvironment (TME), it is imperative to increase PTT efficiency and reduce normal tissue injury by adopting appropriate reactive oxygen species (ROS) and lipid peroxides (LPO) cross-linked with HSPs. In the present research, a potential strategy for mild photothermal treatments (mPTTs) was proposed by initiating localized catalytic chemical reactions in TME based on Pd nanozyme-modified hydrogenated TiO2 (H-TiO2@Pd). In vitro and in vivo evaluations demonstrated that H-TiO2@Pd had good peroxidase-like activities (POD), glutathione oxidase-like activities (GSHOx), and photodynamic properties and also satisfactory biocompatibility for 4T1 cells. Localized catalytic chemical reactions in H-TiO2@Pd significantly depleted GSH to downregulate the protein expression of GPX4 and promoted the accumulation of LPO and ROS, which consumed HSP70 or inhibited its function in 4T1 cells. Hence, the as-constructed low-temperature photothermal therapeutic platform based on Pd nanozyme-modified H-TiO2 can be a promising candidate to develop a safe and effective mPTT for cancer treatments.

In Situ Polymerization of Methylene Blue on Bacterial Cellulose for Photodynamic/Photoelectricity Synergistic Inhibition of Bacterial Biofilm Formation.

In the context of long-term antimicrobial treatment, the emergence of bacterial resistance poses a significant challenge. Therefore, there is a pressing need to develop novel antimicrobial materials and methods that can effectively and safely combat microbial infections. This study focuses on the synthesis of bacterial cellulose-polymethylene blue (BC-PMB) with integrated photodynamic and photoelectric antimicrobial properties. The polymerization of methyl blue (MB) onto bacterial celluloses (BC) was achieved, and through comprehensive computational analyses using density functional theory (DFT) and molecular dynamics simulations, it was confirmed that this polymerization greatly enhanced the binding efficiency between methylene blue and BC. Additionally, polymethylene blue (PMB) exhibited superior photoexcitation efficiency and conductivity compared to its precursor. When BC-PMB was exposed to a 30 mW 660 nm light source for 30 min, the material demonstrated a remarkable antimicrobial efficacy of 93.99% against Escherichia coli and 98.58% against Staphylococcus aureus. Furthermore, the synergistic effect of photodynamic and photoelectric antimicrobial mechanisms exhibited long-term inhibitory capabilities against bacterial biofilms.

Nanoarchitectonics of versatile platform based on graphene oxide for precise and enhanced synergistic cancer photothermal-photodynamic/chemotherapy

The synergy therapy possesses ultrahigh curative effect in the anti-cancer treatment. In this work, nanoscale graphene oxide (NGO) was prepared, loaded with gold nanoparticles (AuNPs) and thiol polyethylene glycol folic acid (SH-PEG1000-FA), and further modified with the photosensitizer methylene blue (MB) or the anticancer drug 5-fluorouracil (5-Fu) to obtain multifunctional nanoplatforms for photothermal-photodynamic synergy (NGO-AuNPs-FA/MB) or photothermal-chemotherapy synergy (NGO-AuNPs-FA/5-Fu), respectively. The results show that NGO-AuNPs-FA has a high drug loading rate and good biocompatibility, and the multifunctional nanoplatform exhibits excellent photodynamic and photothermal properties under laser irradiation. The cell viabilities of NGO-AuNPs-FA/MB and NGO-AuNPs-FA/5-Fu significantly decreased under near-infrared (NIR) laser irradiation, showing excellent in vitro antitumor effects. Therefore, NGO-AuNPs-FA/MB and NGO-AuNPs-FA/5-Fu nanoplatforms achieve synergistic photothermal-photodynamic and photothermal-chemotherapy treatments, respectively, which have promising application prospects in anti-cancer treatment.

Click‐hydrogel delivered aggregation‐induced emissive nanovesicles for simultaneous remodeling and antibiosis of deep burn wounds

AbstractAs 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.

Increased radiosensitivity of melanoma cells through cold plasma pretreatment mediated by ICG.

Radiation therapy (RT) is the primary treatment for many cancers, but its effectiveness is reduced due to radioresistance and side effects. The study aims to investigate an emerging treatment for cancer, cold atmospheric plasma (CAP), as a selectable treatment between cancerous and healthy cells and its role in the occurrence of photodynamic therapy (PDT) utilizing indocyanine green (ICG) as a photosensitizer. We examined whether the efficiency of radiotherapy could be improved by combining CAP with ICG. The PDT effect induced by cold plasma irradiation and the radiosensitivity of ICG were investigated on DFW and HFF cell lines. Then, for combined treatment, ICG was introduced to the cells and treated with radiotherapy, followed by cold plasma treatment simultaneously and 24-h intervals. MTT and colony assays were used to determine the survival of treated cells, and flow cytometry was used to identify apoptotic cells. Despite a decrease in the survival of melanoma cells in CAP, ICG did not affect RT. Comparing the ICG + CAP group with CAP, a significant reduction in cell survival was observed, confirming the photodynamic properties of plasma utilizing ICG. The treatment outcome depends on the duration of CAP. The results for healthy and cancer cells also confirmed the selectivity of plasma function. Moreover, cold plasma sensitized melanoma cells to radiotherapy, increasing treatment efficiency. Treatment of CAP with RT can be effective in treating melanoma. The inclusion of ICG results in plasma treatment enhancement. These findings help to select an optimal strategy for a combination of plasma and radiotherapy.

Near-infrared excited graphene oxide/silver nitrate/chitosan coating for improving antibacterial properties of titanium implants

To design and construct a graphene oxide (GO)/silver nitrate (Ag3PO4)/chitosan (CS) composite coating for rapidly killing bacteria and preventing postoperative infection in implant surgery. GO/Ag3PO4 composites were prepared by ion exchange method, and CS and GO/Ag3PO4 composites were deposited on medical titanium (Ti) sheets successively. The morphology, physical image, photothermal and photocatalytic ability, antibacterial ability, and adhesion to the matrix of the materials were characterized. The GO/Ag3PO4 composites were successfully prepared by ion exchange method and the heterogeneous structure of GO/Ag3PO4 was proved by morphology phase test. The heterogeneous structure formed by Ag3PO4 and GO reduced the band gap from 1.79 eV to 1.39 eV which could be excited by 808 nm near-infrared light. The photothermal and photocatalytic experiments proved that the GO/Ag3PO4/CS coating had excellent photothermal and photodynamic properties. In vitro antibacterial experiments showed that the antibacterial rate of the GO/Ag3PO4/CS composite coating against Staphylococcus aureus reached 99.81% after 20 minutes irradiation with 808 nm near-infrared light. At the same time, the composite coating had excellent light stability, which could provide stable and sustained antibacterial effect. GO/Ag3PO4/CS coating can be excited by 808 nm near infrared light to produce reactive oxygen species, which has excellent antibacterial activity under light.

Unraveling the Optimal Cerium Content for Boosting the Photoresponse Activity of Mixed-Metal Zr/Ce-Based Metal-Organic Frameworks through a Photodynamic and Photocurrent Correlation: Implications on Water Splitting Efficiency.

Mixed-metal-organic frameworks (MMOFs) have emerged as promising photocatalyst candidates in multiple reactions. For instance, the doping of Zr-UiO-type MOFs with Ce atoms increases their photoactivity owing to a better overlap between the organic linker and Ce orbitals. However, it is not clear which is the ideal content of Ce to reach the optimal photocatalytic performance. Herein, a series of MMOFs isostructural to UiO-66 and with napthalene-2,6-dicarboxylate (NDC) as a linker were synthesized and characterized. The Ce content was varied from 0 to 100% and their corresponding structural, chemical, photodynamic, and photoresponse properties were investigated. Powder X-ray diffraction shows that when the content of Ce is 12% onward, in addition to the UiO-type structure, a second crystalline structure is cosynthesized (NDC-Ce). Steady-state and femtosecond (fs) to millisecond (ms) spectroscopy studies reveal the existence of two competing processes: a linker excimer formation and an ultrafast ligand-to-cluster charge transfer (LCCT) phenomenon from the organic linker to Zr/Ce metal clusters. The ultrafast (fs-regime) LCCT process leads to the formation of long-lived charge-separated states, which are more efficiently photoproduced when the content of Ce reaches 9%, suggesting that the related material would show the highest photoactivity. Photoaction spectroscopic measurements corroborate that the sample with 9% of Ce exhibits the maximum photocatalytic efficiency, which is reflected in a 20% increment in overall water splitting efficiency compared with the monometallic Zr-based MOF. The current study demonstrates the relationship between the photodynamical properties of the MMOFs and their photocatalytic performance, providing new findings and opening new ways for improving the design of new MOFs with enhanced photocatalytic activities.

A tumor-targeting fluorescent probe for ratiometric imaging of pH and improving PDT/PTT synergistic therapy

pH is an important indicator of various life activities and is closely associated with cancer. Thus, it is necessary to design an efficient method for detecting pH in tumors and seek a new strategy to enhance the efficiency of tumor therapy. In this paper, a novel tumor-targeting fluorescent probe, Cy-Bio-O, is designed and synthesized. The probe has a good ratiometric response to pH and successfully activates photodynamic and photothermal properties under acidic conditions. In cells experiments, Cy-Bio-O can image pH change by ratiometric signal and show excellent killing ability of cancer cells by PDT/PTT synergistic therapy. Moreover, the probe can image pH of tumor-bearing mice with high signal-to-noise ratio. With the help of tumor-targeting ability, Cy-Bio-O eventually achieve the ablation of solid tumors in tumor-bearing mice mediated by near-infrared (NIR) laser. As far as we known, this is the first exploration and design of a tumor-targeted fluorescent probe for tumor imaging and NIR PDT/PTT dual-modal synergistic therapy.

Nanosilver-decorated covalent organic frameworks for enhanced photodynamic, photothermal, and antibacterial properties

Bacterial infections caused by multidrug-resistant bacteria pose an extremely serious treat to human health However, nanoscale antibacterial materials can effectively inhibit bacterial growth without inducing bacterial resistance. Herein, we have developed a highly effective antibacterial agent by immobilizing silver nanoparticles (AgNPs) within a novel covalent organic framework (COF). The COFBDP/CD-S-3-Ag system was synthesized in situ using BODIPY phoyosensitizer (BDP) and carbon quantum dots (CD-S-3) as precursors. The optimized COFBDP/CD-S-3-Ag system exhibited excellent photodynamic therapy (PDT) and photothermal therapy (PTT). Importantly, the COFBDP/CD-S-3-Ag system, with many active groups, can capture and kill bacteria effectively by interacting with them, thereby contributing to improved antibacterial efficacy. As expected, the designed COFBDP/CD-S-3-Ag system combines the advantages of COFBDP/CD-S-3 (preventing the aggregation of AgNPs and having the ability to capture bacteria) and AgNPs (antibacterial ability), demonstrating excellent antibacterial efficacy. This study developed a new class of antibacterial materials and took an important step forward in promoting the application of COF-based antibacterial materials.

Oxidative cross-linking of biocompatible chitosan injectable hydrogel by perylene-dopamine to boost phototoxicity of perylene on in vitro melanoma and breast cancer therapy

This research focused on improving the photodynamic properties of perylene through a hydrogel formulation in which PBI-DOPA cross-links chitosan chains. Photosensitive CS/PBI-DOPA hydrogel was synthesized through an oxidative cross-linking method and exhibited a biocompatible microporous structure capable of shear thinning behavior and outstanding singlet oxygen quantum efficiency. An in vitro comparative study on the phototoxic and anticancer effects of perylene tetracarboxylic dihydride (PTCDA), free PBI-DOPA and its CS/PBI-DOPA hydrogel formulation on skin cancer (A375), breast cancer (MDA- MB-231) and normal fibroblast cells were performed. The hydrogel formula showed its superiority in reducing the survival of cancer cells while minimizing toxicity in normal cells, compared to both free perylene compounds. Therefore, CS/PBI-DOPA hydrogel could be introduced as a promising biocompatible carrier system with significant efficiency for perylene delivery.

The Antibacterial Effect of Jellyfish-Like pMAG-Au-MnO2 Nanoparticles

Manganese (Mn) has been widely applied in drug resistant bacteria. Although it has advantages such as generating reactive oxygen species (ROS), holding multivalent phases, inducing photothermal effect and biocompatibility, it also brings the disadvantages of increased motility and decreased bacterial adhesion while exerting its advantages. Here, we propose an active antibacterial way by the jellyfish-like anisotropic nanocomposites (JAN), which measures both the advantages and disadvantages of MnO2 nanoparticles (MnNP) together. In this jellyfish-like construct, the spheric gold nanoparticles (AuNP) were covered by MnO2 nanosheets (MnNS), only leaving a bunch of glycopolymers (pMAG) stretching out from a small surface area of AuNP. In JAN, AuNP serves as the main body, possessing a photothermal property; glycopolymers play as the tentacles, binding specifically with Escherichia coli (E. coli); MnNS acts as the shell of jellyfish, initiating by the photo treatment to kill bacteria. The structure and surface properties of JAN were characterized by water contact angle (WCA), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), ultraviolet and visible spectrophotometry (UV-Vis), transmission electron microscope (TEM), dynamic light scattering (DLS), and ellipsometry. The specific antibacterial effect of JAN was evaluated on the growth of both Gram-negative E. coli and Gram-positive Staphylococcus aureus (S. aureus). The results showed that JAN could bind efficiently with E. coli and kill almost all bacteria under near infrared (NIR irradiation, 808[Formula: see text]nm) irradiation for as short as 7 min. This antibacterial effect of JAN can be attributed to their excellent photothermal and photodynamic properties in increasing the temperature to higher than 53[Formula: see text]C and ROS more than 0.45 mmol/L, indicating that the JAN achieved specific and efficient bactericidal effect due to their unique nanostructure and surface properties. In this study, we report for the first time on the synthesis strategy of jellyfish-like anisotropic nanoparticles and their specific bactericidal effect. Our work provides new possibilities for the application of anisotropic nanoparticles to inhibit bacterial growth.

Chlorination-Mediated π-π Stacking Enhances the Photodynamic Properties of a NIR-II Emitting Photosensitizer with Extended Conjugation.

NIR-II-emitting photosensitizers (PSs) have attracted great research interest due to their promising clinical applications in imaging-guided photodynamic therapy (PDT). However, it is still challenging to realize highly efficient PDT on NIR-II PSs. In this work, we develop a chlorination-mediated π-π organizing strategy to improve the PDT of a PS with conjugation-extended A-D-A architecture. The significant dipole moment of the carbon-chlorine bond and the strong intermolecular interactions of chlorine atoms bring on compact π-π stacking in the chlorine-substituted PS, which facilitates energy/charge transfer and promotes the photochemical reactions of PDT. Consequently, the resultant NIR-II emitting PS exhibits a leading PDT performance with a yield of reactive oxygen species higher than that of previously reported long-wavelength PSs. These findings will enlighten the future design of NIR-II emitting PSs with enhanced PDT efficiency.

Chlorination‐Mediated π–π Stacking Enhances the Photodynamic Properties of a NIR‐II Emitting Photosensitizer with Extended Conjugation

AbstractNIR‐II‐emitting photosensitizers (PSs) have attracted great research interest due to their promising clinical applications in imaging‐guided photodynamic therapy (PDT). However, it is still challenging to realize highly efficient PDT on NIR‐II PSs. In this work, we develop a chlorination‐mediated π–π organizing strategy to improve the PDT of a PS with conjugation‐extended A‐D‐A architecture. The significant dipole moment of the carbon‐chlorine bond and the strong intermolecular interactions of chlorine atoms bring on compact π–π stacking in the chlorine‐substituted PS, which facilitates energy/charge transfer and promotes the photochemical reactions of PDT. Consequently, the resultant NIR‐II emitting PS exhibits a leading PDT performance with a yield of reactive oxygen species higher than that of previously reported long‐wavelength PSs. These findings will enlighten the future design of NIR‐II emitting PSs with enhanced PDT efficiency.

CuS Hybrid Hydrogel for Near-Infrared-Enhanced Infected Wound Healing: A Gelatin-Assisted Synthesis and Direct Incorporation Strategy

Developing antibacterial hydrogels, with good mechanical strength and self-healing ability to resist bacterial invasion and accelerate skin regeneration, is critical for infected full-thickness skin wound treatment. Herein, we report a gelatin-assisted synthesis and direct incorporation strategy to construct a CuS hybrid hydrogel for infected wound healing applications. CuS nanodots (NDs) were synthesized directly inside a gelatin host matrix (Gel-CuS), and these tightly confined and evenly distributed CuS NDs displayed superb dispersibility and stability against oxidation. Gel-CuS was then used to crosslink with oxidized dextran (ODex) to form a Gel-CuS-8/ODex hydrogel (8 stands for the concentration of CuS, in mM) via a facile Schiff-base reaction, which exhibited improved mechanical properties, excellent adhesion and self-healing ability, suitable swelling and degradation behavior, and good biocompatibility. The Gel-CuS-8/ODex hydrogel can act as an efficient antibacterial agent due to its photothermal and photodynamic properties under a 1064 nm laser irradiation. Furthermore, in animal experiments, when being applied as wound dressing, the Gel-CuS-8/ODex hydrogel significantly promoted infected full-thickness cutaneous wound healing through improved epidermis and granulation tissue formation and accelerated generation of new blood vessels, hair follicles, and collagen deposition after proper near-infrared irradiation treatment. This work provides a promising strategy to synthesize functional inorganic nanomaterials tightly and evenly embedded inside modified natural hydrogel networks for wound healing applications.

Photodynamic Alginate Zn-MOF Thermosensitive Hydrogel for Accelerated Healing of Infected Wounds

Antibiotic resistance reduces the effectiveness of infected wound healing, and it is necessary to develop a new strategy to promote infected wound healing without using antibiotics. Here, we develop a Chlorin e6 (Ce6)-loaded zinc-metal-organic framework (MOF) thermosensitive hydrogel (Ce6@MOF-Gel) based on alginate and poly(propylene glycol) 407, which enhances antibacterial effects and promotes infected wound healing by a novel strategy of combining zinc-MOF with photodynamic therapy (PDT). Zinc-MOF can realize acid-responsive release of Ce6 and improve antibacterial performance without drug resistance by destroying the integrity of bacterial cell membranes and enhancing the production of bacterial reactive oxygen species (ROS). Additionally, Ce6@MOF-Gel enhances the stability, solubility, and photodynamic properties of Ce6. More importantly, Ce6@MOF-Gel reduces inflammation and promotes collagen deposition and re-epithelialization to facilitate infected wound healing. Collectively, the photodynamic MOF-based hydrogel provides a new, efficient, and safe way for accelerated healing of infected wounds.

A photoactive self-healing carboxymethyl chitosan-based hydrogel for accelerated infected wound healing through simultaneously modulating multiple critical tissue repair factors

Infected wounds cause severe medical complications and even chronic mortality, leading to persistent health burdens. Therefore, the enhancement of wound healing has been a major goal of medical researchers. Herein, a photoactive self-healing hydrogel (termed as Macropatch), composed of carboxymethyl chitosan (CMCS), tannic acid (TA) and graphitic carbon nitride g-C3N4 (GCN), was developed to promote wound healing through simultaneously modulating pathological related factors. We identified that dynamic hydrogen bond, hydrophobic interaction and crosslinking between hydrogel backbones endowed Macropatch with good self-healing capability and mechanical property, allowing for protecting the wound from further injury. In addition, Macropatch exhibited superior tissue adhesiveness and cell affinity due to numerous catechol groups of TA chains, and enabled tight wound adhesion to seal organ bleeding. Specifically, GCN endowed Macropatch with improving mechanical strength, self-healing ability and especially visible light-induced antibacterial activity, leading to a fast recovery of bacteria-infected wounds. More remarkably, benefiting from inherent and photodynamic antibacterial properties, Macropatch could prevent bacterial infections under visible light irradiation, and consequently increase the collagen synthesis and re-epithelization, accelerating bacteria-infected wound healing process. Overall, photoactive Macropatch is a safe wound dressing with the potential of overcoming challenges in infectious wound healing, and might be applied in clinical condition.