Fabrication of copper ions-substituted hydroxyapatite/polydopamine nanocomposites with high antibacterial and angiogenesis effects for promoting infected wound healing

Mussel-Inspired MXene/Antimicrobial Peptide-Integrated Photosensitive Poly(vinyl alcohol)-Based Hydrogel with Antibacterial, Anti-Inflammatory, and Electroactive Properties for Accelerated Wound Healing

Backgrounds: The buildup of reactive oxygen species (ROS) in infected wounds triggers an excessive inflammatory response, while the overuse of antibiotics has contributed to increased bacterial resistance. Therefore, developing wound dressings that effectively eliminate ROS and inhibit bacterial growth is crucial. Methods: Inspired by mussel-derived proteins, we developed a polydopamine (PDA)-grafted MXene (PDA@MXene) and 3,4-dihydroxyphenylalanine-PonG1 (DOPA-PonG1)-modified photosensitive poly(vinyl alcohol) (PVA) hydrogel as a wound dressing. PDA@MXene was synthesized through dopamine self-polymerization on the MXene surface, while tyrosine hydroxylation was used to introduce DOPA into the antibacterial peptide ponericin G1 (PonG1). The hydrogel and its components were characterized, and their morphology was examined. The hydrogel's hemostatic ability, mechanical properties, and conductivity were evaluated. In vitro studies systematically evaluated antioxidative effects, antibacterial activity, biocompatibility, and expression of tissue regeneration-related factors. An infected full-thickness skin defect model was established in vivo, and different hydrogel treatments were applied. The wound-healing rate was then measured, followed by histological analysis using hematoxylin and eosin, Masson, Sirius Red, and immunofluorescence staining to investigate the healing mechanism. Results: The DOPA sequence enhanced PonG1 stability on the hydrogel surface, leading to sustained antibacterial ability. PDA@MXene significantly improved the hydrogel's conductivity and mechanical strength. Notably, the combined effects of DOPA-PonG1 and PDA@MXene contributed to enhanced antibacterial and ROS-scavenging properties. In vivo findings demonstrated that the DOPA-PonG1/PDA@MXene/PVA hydrogel accelerated infected wound healing by promoting angiogenesis and collagen deposition while reducing excessive inflammation. This study presents an innovative approach for treating infected wound defects and holds promise for clinical applications.

Polydopamine-modified hydroxyapatite and manganese tetroxide nanozyme incorporated gelatin methacryloyl hydrogel: A multifunctional platform for anti-bacteria, immunomodulation, angiogenesis, and enhanced regeneration in infected wounds

Intensive inflammation induced via bacterial infection seriously disturbs the immune-microenvironment and compromise the neovascularization in the skin wound. On the basis of reducing bacterial infections, alleviating inflammatory response and rebuild the crosstalk between macrophages and vascular endothelial cell (VEC) serve as the key strategy for facilitating infected wound healing. Herein, manganese tetroxide (Mn3O4) nanozymes and polydopamine-coated hydroxyapatite (PHA) nanoparticles were loaded on the gelatin methacryloyl (GelMA) hydrogel, which was subsequently crosslinked by the UV light to construct a multifunctional hydrogel wound dressing GelMA-PHA-Mn3O4 with excellent anti-bacterial, immuno-regulation and angiogenic properties. Triggered by near infrared (NIR), PHA exhibited photothermal effect and effectively eradicated Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) biofilm. On the other hand, Mn3O4 nanozymes in hydrogel exhibit desirable reactive oxygen species (ROS) scavenging capacity due to the redox cycle between Mn2+ and Mn3+, which successfully transform the LPS-induced macrophage phenotype from pro-inflammation M1 to anti-inflammation M2. Notably, the interaction between macrophages and VECs was subsequently reconstructed and exhibited an evident pro-angiogenic phenomenon along with the improvement of local immuno-microenvironment. In vivo study further verified that the GelMA-PHA-Mn3O4 hydrogel combined with NIR irradiation could accelerate the healing of infected wound through the prominent anti-bacterial and immuno-regulation effect. The collagen deposition and formation of blood vessel in the wound were active. Above, this study demonstrated that the GelMA-PHA-Mn3O4 hydrogel represents a promising approach for managing infected wounds, with an anticipated prospect in clinical application.

Dissolving PEGDA-Based Microneedles to Transdermally Deliver PDA@Cu with Photothermal Properties for Potential Antibacterial Applications

The stratum corneum of the skin functions as a barrier, obstructing drug absorption and complicating the treatment of skin infections caused by pathogens such as bacteria, fungi, and viruses through topical methods. In this research, a microneedle patch was developed, which consists of gelatin-sucrose (SG) that encapsulates polydopamine-copper nanoparticles (PDA@Cu) at the tip for antibacterial purposes. Poly(ethylene glycol) diacrylate (PEGDA) served as the primary substrate for the microneedle shaft (PDA@Cu-SG/PEGDA). This patch was engineered to enhance skin permeability and facilitate the efficient delivery of drugs through the rapid dissolution of the tips. Coordinate bonds can be formed between PDA and Cu ions, resulting in the immobilization of Cu particles on the PDA surface, which aids in the green synthesis of PDA@Cu photothermal antibacterial particles. The SG polymer, which contained PDA@Cu, was employed to fill the tip cavities through a series of centrifugation steps. Subsequently, UV-induced polymerization was carried out to produce PEGDA microneedles with hydrophilic tips (PDA@Cu-SG/PEGDA). Furthermore, the physicochemical characteristics of the polymer microneedles, including morphology, composition, and mechanical strength, were thoroughly characterized. These microneedles with hydrophilic tips demonstrated sufficient mechanical strength. Owing to the ability of PDA@Cu to disrupt bacterial membranes, the microneedle patch demonstrated excellent in vitro antibacterial efficacy. We validated the antibacterial activity of the microneedle patch against Escherichia coli and Staphylococcus aureus by conducting in vitro bacterial plate coating assays. The results of the assays indicated that this minimally invasive strategy achieved broad-spectrum antibacterial effects; thus, this may be a suitable approach for managing polymicrobial skin infections during clinical trials.

Chitosan gel loaded with carbon dots and mesoporous hydroxyapatite nanoparticles as a topical formulation for skin regeneration: An animal study

BACKGROUND

Carbon dots (CDs) are the research hotspots in antimicrobial applications. Also, due to the importance of calcium ions in skin regeneration, mesoporous hydroxyapatite nanoparticles (mHAP NPs) were prepared. This study aimed to evaluate the wound healing efficiency of both CD and mHAP NPs simultaneously.

METHODS

We doped Fluorine (F) and Copper (Cu) in CDs to prepare Cu*F-doped CDs (Cu.CDs). For the rapid release of calcium ions, a novel double-surfactant system (CTAB/F-127) was used for the synthesis of mHAP NPs. Then, we loaded both Cu.CDs and mHAP NPs simultaneously into the chitosan (CTS) gel.

RESULTS

The released calcium for mHAP NPs prepared using CTAB/F-127 was proved about 30 % higher than that prepared using only CTAB, after one day. The BET-specific surface area for mHAP NPs prepared using CTAB/F-127 was 23.17 % more than that prepared using only CTAB. This high porosity improves wound exudate absorption. Rheological analysis showed that the addition of both mHAP NPs and Cu.CD decreases the viscosity of CTS gel and thereby makes it suitable for topical applications. CTS gel containing mHAP + Cu.CDs indicated exceptional antibacterial properties even without light and/or H2O2 with an inhibition zone diameter of 35 and 17 mm for E. coli and S. aureus species, respectively. CTS gel containing mHAP + Cu.CDs also showed significantly higher wound closure efficacy, greater inflammation inhibition, and better re-epithelialization than the other groups in rats with full-thickness skin wounds.

CONCLUSION

The CTS gel containing both Cu.CD and mHAP NPs can be proposed as a new therapeutic gel for wound healing.

Advancing diabetic wound care: The role of copper-containing hydrogels

Diabetic wounds pose a significant challenge in healthcare due to their complex nature and the difficulties they present in treatment and healing. Impaired healing processes in individuals with diabetes can lead to complications and prolonged recovery times. However, recent advancements in wound healing provide reasons for optimism. Researchers are actively developing innovative strategies and therapies specifically tailored to address the unique challenges of diabetic wounds. One focus area is biomimetic hydrogel scaffolds that mimic the natural extracellular matrix, promoting angiogenesis, collagen deposition, and the healing process while also reducing infection risk. Copper nanoparticles and copper compounds incorporated into hydrogels release copper ions with antimicrobial, anti-inflammatory, and angiogenic properties. Copper reduces infection risk, modulates inflammatory response, and promotes tissue regeneration through cell adhesion, proliferation, and differentiation. Utilizing copper nanoparticles has transformative potential for expediting diabetic wound healing and improving patient outcomes while enhancing overall well-being by preventing severe complications associated with untreated wounds. It is crucial to write a review highlighting the importance of investigating the use of copper nanoparticles and compounds in diabetic wound healing and tissue engineering. These groundbreaking strategies hold the potential to transform the treatment of diabetic wounds, accelerating the healing process and enhancing patient outcomes.

Photothermal Antibacterial and Osteoinductive Polypyrrole@Cu Implants for Biological Tissue Replacement

The treatment of bone defects caused by disease or accidents through the use of implants presents significant clinical challenges. After clinical implantation, these materials attract and accumulate bacteria and hinder the integration of the implant with bone tissue due to the lack of osteoinductive properties, both of which can cause postoperative infection and even lead to the eventual failure of the operation. This work successfully prepared a novel biomaterial coating with multiple antibacterial mechanisms for potent and durable and osteoinductive biological tissue replacement by pulsed PED (electrochemical deposition). By effectively regulating PPy (polypyrrole), the uniform composite coating achieved sound physiological stability. Furthermore, the photothermal analysis showcased exceptional potent photothermal antibacterial activity. The antibacterial assessments revealed a bacterial eradication rate of 100% for the PPy@Cu/PD composite coating following a 24 h incubation. Upon the introduction of NIR (near-infrared) irradiation, the combined effects of multiple antibacterial mechanisms led to bacterial reduction rates of 99% for E. coli and 98% for S. aureus after a 6 h incubation. Additionally, the successful promotion of osteoblast proliferation was confirmed through the application of the osteoinductive drug PD (pamidronate disodium) on the composite coating's surface. Therefore, the antimicrobial Ti-based coatings with osteoinductive properties and potent and durable antibacterial properties could serve as ideal bone implants.

Gelatin‑sodium alginate composite hydrogel doped with black phosphorus@ZnO heterojunction for cutaneous wound healing with antibacterial, immunomodulatory, and angiogenic properties

Hydrogels with novel antimicrobial properties and accelerated wound healing are of great interest in the field of wound dressings because they not only prevent bacterial infections but also fulfill the essential needs of wound healing. In this study, multifunctional hydrogel dressings consisting of black phosphorus nanosheets(BPNS) surface-modified Zinc oxide (BP@ZnO heterojunction) based on gelatin (Gel), sodium alginate (SA), glutamine transferase (mTG), and calcium ions with a three-dimensional crosslinked network were prepared. The BP@ZnO-Gel/SA hydrogel has excellent mechanical properties, hemocompatibility (hemolysis rate: 3.29 %), swelling rate(832.8 ± 19.2 %), cytocompatibility, photothermal and photodynamic antibacterial properties(Sterilization rate: 96.4 ± 3.3 %). In addition, the hydrogel accelerates wound healing by promoting cell migration, immune regulation and angiogenesis. Thus, this hydrogel achieves the triple effect of antimicrobial, immunomodulation and angiogenesis, and is a tissue engineering strategy with great potential.

Improving osseointegration and antimicrobial properties of titanium implants with black phosphorus nanosheets-hydroxyapatite composite coatings for vascularized bone regeneration

For decades, titanium implants have shown impressive advantages in bone repair. However, the preparation of implants with excellent antimicrobial properties as well as better osseointegration ability remains difficult for clinical application. In this study, black phosphorus nanosheets (BPNSs) were doped into hydroxyapatite (HA) coatings using electrophoretic deposition. The coatings' surface morphology, roughness, water contact angle, photothermal properties, and antibacterial properties were investigated. The BP/HA coating exhibited a surface roughness of 59.1 nm, providing an ideal substrate for cell attachment and growth. The water contact angle on the BP/HA coating was measured to be approximately 8.55°, indicating its hydrophilic nature. The BPNSs demonstrated efficient photothermal conversion, with a temperature increase of 42.2°C under laser irradiation. The BP/HA composite coating exhibited a significant reduction in bacterial growth, with inhibition rates of 95.6% and 96.1% against Staphylococcus aureus and Escherichia coli. In addition, the cytocompatibility of the composite coating was evaluated by cell adhesion, CCK8 and AM/PI staining; the effect of the composite coating in promoting angiogenesis was assessed by scratch assay, transwell assay, and protein blotting; and the osteoinductivity of the composite coating was evaluated by alkaline phosphatase assay, alizarin red staining, and Western blot. The results showed that the BP/HA composite coating exhibited superior performance in promoting biological functions such as cell proliferation and adhesion, antibacterial activity, osteogenic differentiation, and angiogenesis, and had potential applications in vascularized bone regeneration.

Photothermal Carbon Dots Chelated Hydroxyapatite Filler: High Photothermal Conversion Efficiency and Enhancing Adhesion of Hydrogel

The synthesis of photothermal carbon/hydroxyapatite composites poses challenges due to the binding modes and relatively low photothermal conversion efficiency. To address these challenges, the calcium ions chelated by photothermal carbon dots (PTC-CDs) served as the calcium source for the synthesis of photothermal carbon dots chelated hydroxyapatite (PTC-HA) filler via the coprecipitation method. The coordination constant K and chelation sites of PTC-HA were 7.20 × 102 and 1.61, respectively. Compared to PTC-CDs, the coordination constant K and chelation sites of PTC-HA decreased by 88 and 35% due to chelating to hydroxyapatite, respectively. PTC-HA possesses fluorescence and photothermal performance with a 62.4% photothermal conversion efficiency. The incorporation of PTC-HA filler significantly enhances as high as 76% the adhesion performance of the adhesive hydrogel. PTC-HA with high photothermal conversion efficiency and enhancing adhesion performance holds promise for applications in high photothermal conversion efficiency, offering tissue adhesive properties and fluorescence capabilities to the hydrogel.

Microenvironment-responsive Cu-phenolic networks coated nanofibrous dressing with timely macrophage phenotype transition for chronic MRSA infected wound healing

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a pressing clinical issue that impedes wound healing. Pro-inflammatory M1 macrophages is required to clear bacteria and recruit various cell types during the initial phase of wound healing, but timing of this process is crucial. Herein, a microenvironment-responsive nanofibrous dressing capable of timely macrophage phenotype transition in vivo is constructed by coating copper ions (Cu2+)-polydopamine (PDA) networks on poly (ε-caprolactone) fiber (PCL-fiber) membrane. During the initial post-implantation period, the nanofibrous dressing show pH-sensitive Cu2+ release in the acidic infection microenvironment. The release Cu2+ have a direct killing effect on MRSA, and promote the proinflammatory M1 phenotype of macrophages to enhance the antibacterial macrophage response. Later, PDA to become a reactive oxygen species (ROS) scavenger when in microenvironments with elevated ROS levels, which conferred the dressing with an immunomodulatory activity that convert M1 macrophages into M2 macrophages. In vivo examination in an MRSA infected full-thickness skin wounds of rat model demonstrates that this dressing significantly facilitated infection eradication and wound healing through modulating local inflammatory phenotype. Overall, this study offers a simple and effective approach for timely manipulation of inflammation progression to promote infected wound healing.

Dramatic reduction of toxicity of Poly(hexamethylene guanidine) disinfectant by charge neutralization

The current study aimed to investigate the toxicity of positively charged polyhexamethylene guanidine (PHMG) polymer and its complexation with different anionic natural polymers such as k-carrageenan (kCG), chondroitin sulfate (CS), sodium alginate (Alg.Na), polystyrene sulfonate sodium (PSS.Na) and hydrolyzed pectin (HP). The physicochemical properties of the synthesized PHMG and its combination with anionic polyelectrolyte complexes (PECs) namely PHMG:PECs were characterized using zeta potential, XPS, FTIR, and TG analysis. Furthermore, cytotoxic behavior of the PHMG and PHMG:PECs, respectively, were evaluated using human liver cancer cell line (HepG2). The study results revealed that the PHMG alone had slightly higher cytotoxicity to the HepG2 cells than the prepared polyelectrolyte complexes such as PHMG:PECs. The PHMG:PECs showed a significant reduction of cytotoxicity to the HepG2 cells than the pristine PHMG alone. A reduction of PHMG toxicity was observed may be due to the facile formation of complexation between the positively charged PHMG and negatively charged anionic natural polymers such as kCG, CS, Alg. Na, PSS.Na and HP, respectively, via charge balance or neutralization. The experimental results indicate that the suggested method might significantly lower PHMG toxicity while improving biocompatibility.

k-Carrageenan based magnetic@polyelectrolyte complex composite hydrogel for pH and temperature-responsive curcumin delivery

The dual stimuli-responsive drug delivery system has attracted a lot of interest in controlled drug delivery to specific sites. The magnetic iron oxide nanoparticles integrated polyelectrolyte complex-based hydrogel (MPEC HG) system was developed in this work. First, magnetic nanoparticles were produced in situ in the synthetic polymer polyhexamethylene guanidine (PHMG). Furthermore, the natural biopolymer k-carrageenan (kCG) was employed to form the polyelectrolyte complex (PEC) through charge-balancing interaction between positively charged guanidine units and negatively charged sulfonate groups. Various characterization approaches were used to characterize the developed magnetic polyelectrolyte complex hydrogel (MPEC HG) system. Curcumin (Cur) was employed as a model bioactive agent to examine the drug loading and stimuli-responsive drug release efficiency of the MPEC HG system. Under the combined pH and temperature stimuli conditions (pH 5.0/42 °C), the developed hydrogel system demonstrated great drug loading efficiency (~ 68 %) and enhanced drug release. Furthermore, the MPEC HG system's in vitro cytotoxicity behavior was investigated on a human liver cancer (HepG2) cell line, and the results revealed that the MPEC HG system is biocompatible. As a result, the MPEC HG system might be used for dual pH and temperature stimuli-responsive drug delivery applications in cancer therapy.

Metal ions doping effect on the physicochemical, antimicrobial, and wound healing profiles of alginate-based composite

The alginate (Alg) matrix with immobilized hydroxyapatite (HAp) and zinc oxide (ZnO), cross-linked by chitosan (CS) and metal ions (Meⁿ⁺) Ca²⁺, Zn²⁺, and Cu²⁺ was created as a wound dressing. The effect of Meⁿ⁺ and their concentrations on water vapor transition, fluid handling, dehydration, drug release, and healing are shown. Me-containing samples have a lower sorption capacity, than a commercial Kaltostat, however, a much lower degree of their dehydration provides a longer wound wet. The Meⁿ⁺ presence lowers the environmental pH to slightly acidic values promoting healing. Ca²⁺, Zn²⁺, and Cu²⁺ in complexes with CS increase antimicrobial effect against E. coli and S. aureus, slow down the Anaesthesine release, making it compatible with Fickian diffusion in the Zn²⁺ and Cu²⁺ presence, and non-Fickian transport under Ca²⁺ influence. The material promotes the proliferation of the fibroblasts, an increase of collagen fibres, and new arterial and venous capillaries, indicating the intensity of the healing process.

Fabrication and properties of multi-functional polydopamine coated Cu/F-codoped hydroxyapatite hollow microspheres as drug carriers

Due to its excellent bone conductivity and drug adsorption as well as pH-responsive drug release property, hydroxyapatite (HAp) is widely used as a drug carrier in bone repair field. Here, we report for the first time a novel multi-functional polydopamine (PDA) coated Cu/F-codoped HAp (Cu/F-HAp-PDA) hollow microspheres. Both Cu²⁺ and F^- were successfully doped into the lattice of HAp and uniformly distributed in the shell of hollow microspheres through a one-step hydrothermal synthesis. Then PDA was coated homogeneously on the outer layer of Cu/F-HAp hollow microspheres. Both Cu/F-HAp and Cu/F-HAp-PDA samples displayed high drug loading efficiency and pH responsive drug release behavior. Moreover, the obtained Cu/F-HAp-PDA hollow microspheres exhibited excellent photothermal conversion efficiency and photothermal stability. The molecular dynamics simulations showed that PDA and HAp can form mutual binding mainly through Ca-O bonding, while doxorubicin (DOX) is mainly bound to PDA molecules through hydrogen bonding and π-π stacking interaction.

Photothermal Hydrogels for Promoting Infected Wound Healing

Photothermal therapies (PTT), with spatiotemporally controllable antibacterial capabilities without inducing resistance, have shown encouraging prospects in the field of infected wound treatments. As an important platform for PTT, photothermal hydrogels exhibit attractive advantages in the field of infected wound treatment due to their excellent biochemical properties and have been intensively explored in recent years. This review summarizes the progress of the photothermal hydrogels for promoting infected wound healing. Three major elements of photothermal hydrogels, i.e., photothermal materials, hydrogel matrix, and construction methods, are introduced. Furthermore, different strategies of photothermal hydrogels in the treatment of infected wounds are summarized. Finally, the challenges and prospects in the clinical treatment of photothermal hydrogels are discussed.

Amphiphilic sodium alginate-polylysine hydrogel with high antibacterial efficiency in a wide pH range

Bacterial infection is a major pathological factor leading to persistent wounds. With the aging of population, wound infection has gradually become a global health-issue. The wound site environment is complicated, and the pH changes dynamically during healing. Therefore, there is an urgent need for new antibacterial materials that can adapt to a wide pH range. To achieve this goal, we developed a thymol-oligomeric tannic acid/amphiphilic sodium alginate-polylysine hydrogel film, which exhibited excellent antibacterial efficacy in the pH range from 4 to 9, achieving the highest achievable 99.993 % (4.2 log units) and 99.62 % (2.4 log units) against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, respectively. The hydrogel films exhibited excellent cytocompatibility, suggesting that the materials are promising as a novel wound healing material without the concern of biosafety.

Fabrication of mechanically advanced polydopamine decorated hydroxyapatite/polyvinyl alcohol bio-composite for biomedical applications: In-vitro physicochemical and biological evaluation

In this study, polydopamine (PDA) coated hydroxyapatite (HA) reinforced polyvinyl alcohol (PVA) films were produced to be used in biomedical applications such as bone tissue regeneration. pDA is coated not only to prevent the agglomeration of HA when encountering interstitial fluids but also to strongly bind the PVA for the interaction between materials so that the mechanical performance becomes more stabilized. pDA was coated on the hydroxyapatite surface using a radical polymerization technique, and the reinforced PVA were produced with pDA-coated HA (pDA-HA/PVA) nanoparticles. Fundamental characteristic properties of pDA-HA/PVA nanocomposite films were examined by morphological/chemical (SEM-EDS), microstructural (XRD, Ft-IR, and Raman), thermodynamic (TGA and TM), mechanical performance (Vickers microhardness) and biological activity analysis (MTT, genotoxicity and antimicrobial efficacy investigations). Physicochemical analysis showed that all the samples studied exhibited homogeneous mineral distributions through the main structures. According to TGA, TMA and hardness tests, the new composite structure possessed higher mechanical properties than neat PVA. Further, pDA-HA/PVA nanocomposites exhibited high antibacterial capacities against Acinetobacter Baumannii (A.Baumannii), Staphylococcus aureus (S. aureus), and Streptococcus mutans (S.mutans). Moreover, the new nanocomposites were noted to present good biocompatibility for fibroblast (L929) cells and to support remarkably MCS cells. All in all, this comprehensive work shows that the thermo-mechanically improved pDA-HA/PVA films will increase the application fields of PVA in biomedical fields especially tooth-bone treatments for coating, filling, or occlusion purposes.

Biodegradable manganese-doped hydroxyapatite antitumor adjuvant as a promising photo-therapeutic for cancer treatment

The efficiency of a cancer therapy agent depends on its ability to eliminate tumors without endangering neighboring healthy tissues. In this present study, a novel multifunctional property enriched nanostructured system was synthesized on manganese-doped hydroxyapatite (Mn-HAp) conjugated with counter folic acid (FA) IR-783 fluorescence dye. The tailored synthesis of nano rod-shaped Mn-HAp nanoparticles with high surface area allows to conjugate FA/IR-783 dye which enhanced retention time during in vivo circulation. The drug-free Photothermal Photodynamic therapy mediated cancer treatment permits the prevention of collateral damages to non-cancerous cells. The safe HAp biomaterial matrix allows a large number of molecules on its surface due to its active different charge moieties (Ca²⁺/PO₄ ^3-) without any recurrence toxicity. The doped Mn allows releasing of Mn²⁺ ions which triggered the production of toxic hydroxyl radicals (•OH) via Fenton or Fenton-like reactions to decompose H₂O₂ in the tumor sites. Herein, IR-783 and FA were selected for targeted fluorescence imaging-guided photothermal therapy. 6The PTT performance of synthesized nanostructured system shows enhanced potential with ∼60°C temperature elevation with 0.75 W∙cm^-2 power irradiated within 7 min of treatment. PDT activity was also observed initially with Methylene Blue (MB) as a targeted material which shows a drastic degradation of MB and further in vitro studies with MDA-MB-231 breast cancer cell line show cytotoxicity due to the generated reactive oxygen species (ROS) effect. FA/IR-783 conjugated Mn-HAp nanoparticles (2.0 mol% Mn-HAp/FA-IR-783) show significant tumor-specific targeting and treatment efficiency while intravenously injected in (tail vain) BALB/c nude mice model without any recurrence. The synthesized nanostructured system had ample scope to be a promising Photo-Therapeutic agent for cancer treatment.

Aramid Nanofibers-Reinforced Rhein Fibrous Hydrogels as Antibacterial and Anti-Inflammatory Burn Wound Dressings

Burn injuries are one of the most devastating traumas. The development of polymer-based hydrogel dressings to prevent bacterial infection and accelerate burn wound healing is continuously desired. Mechanical strong hydrogels that encapsulated antibacterial drugs have gained increasing attention. Herein, aramid nanofibers (ANFs)-reinforced rhein fibrous hydrogels (ANFs/Rhein) were fabricated through a one-pot procedure to serve as a possible treatment for the Staphylococcus aureus-infected burn wound. ANFs preserved the highly aligned backbones and the mechanical properties of Kevlar, and its combination with an antibacterial drug rhein produced a composite hydrogel that possesses favorable physicochemical properties including appropriate mechanical strength, high water holding capacity, satisfactory antibacterial efficiency, and excellent biocompatibility. As wound dressings, ANFs/Rhein hydrogels provided a moist environment for the wound site and released antibacterial drugs continuously to improve the wound healing rate by efficiently restraining bacterial infection, reducing inflammation, enhancing collagen deposition, and promoting the formation of blood vessels, in this way to offer a potential treatment strategy for bacteria-associated burn wound healing.

Morphological Changes, Antibacterial Activity, and Cytotoxicity Characterization of Hydrothermally Synthesized Metal Ions-Incorporated Nanoapatites for Biomedical Application

The objective of this study was to prepare hydroxyapatite (HA) with potential antibacterial activity against gram-negative and gram-positive bacteria by incorporating different atomic ratios of Cu²⁺ (0.1–1.0%), Mg²⁺ (1.0–7.0%), and Zn²⁺ (1.0–7.0%) to theoretically replace Ca²⁺ ions during the hydrothermal synthesis of grown precipitated HA nanorods. This study highlights the role of comparing different metal ions on synthetic nanoapatite in regulating the antibacterial properties and toxicity. The comparisons between infrared spectra and between diffractograms have confirmed that metal ions do not affect the formation of HA phases. The results show that after doped Cu²⁺, Mg²⁺, and Zn²⁺ ions replace Ca²⁺, the ionic radius is almost the same, but significantly smaller than that of the original Ca²⁺ ions, and the substitution effect causes the lattice distance to change, resulting in crystal structure distortion and reducing crystallinity. The reduction in the length of the nanopatites after the incorporation of Cu²⁺, Mg²⁺, and Zn²⁺ ions confirmed that the metal ions were mainly substituted during the growth of the rod-shape nanoapatite Ca²⁺ distributed along the longitudinal site. The antibacterial results show that nanoapatite containing Cu²⁺ (0.1%), Mg²⁺ (3%), and Zn²⁺ (5–7%) has obvious and higher antibacterial activity against gram-positive bacteria Staphylococcus aureus within 2 days. The antibacterial effect against the gram-negative bacillus Escherichia coli is not as pronounced as against Staphylococcus aureus. The antibacterial effect of Cu²⁺ substituted Ca²⁺ with an atomic ratio of 0.1~1.0% is even better than that of Mg²⁺- and Zn²⁺- doped with 1~7% groups. In terms of cytotoxicity, nanoapatites with Cu²⁺ (~0.2%) exhibit cytotoxicity, whereas Mg²⁺- (1–5%) and Zn²⁺- (~1%) doped nanoapatites are biocompatible at low concentrations but become cytotoxic as ionic concentration increases. The results show that the hydrothermally synthesized nanoapatite combined with Cu²⁺ (0.2%), Mg²⁺ (3%), and Zn²⁺ (3%) exhibits low toxicity and high antibacterial activity, which provides a good prospect for bypassing antibiotics for future biomedical applications.

Polydopamine, harness of the antibacterial potentials-A review

Antibiotic resistance is one of the major causes of morbidity and mortality, triggered by the adhesion of microbes and to some extent the formation of biofilms. This condition has been quite challenging in the health and industrial sector. Conditions and processes required to foil these infectious and resistance are of much concern. The synthesis of PDA material, inspired by the Mytilus edulis foot protein (MEFP)5 possesses unique characteristics that allow for, adhesion, photothermal therapy, synergistic effects with other materials, biocompatibility process, etc. Therefore, their usage holds great potential for dealing with both the infectious nature and the antibiotic resistance processes. Hence, this review provides an overview of the mechanism involved in accomplishing and eradicating bacteria, the recently harnessed antibacterial effect of the PDA through other properties they possess, a way forward in tapping the benefit embedded in the PDA, and the future perspective.

Effect of electrochemical oxidation and drug loading on the antibacterial properties and cell biocompatibility of titanium substrates

A combination of \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${\text{ TiO}}_{2}$$\end{document}TiO2 nanotube array (TON) and controlled drug release system is employed to provide enhanced surface properties of titanium implants. Electrochemical anodization process is used to generate TON for introducing, vancomycin, an effective antibacterial drug against Staphylococcusaureus. TON loaded vancomycin is then coated with a number of layers of 10% gelatin using spin coating technique. The gelatin film is reinforced with graphene oxide (GO) nanoparticles to improve the surface bioactivity. The surface of the samples is characterized by field emission electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and contact angle measurement. The results illustrate that the TON was constructed and vancomycin molecules are successfully loaded. The drug release study shows that the amount of released vancomycin is controlled by the thickness of gelatin layers. With an increase in gelatin film layers from 3 to 7, the release of vancomycin in the burst release phase decreased from 58 to 31%, and sustained release extended from 10 to 17 days. The addition of GO nanoparticles seems to reduce drug release in from 31 to 22% (burst release phase) and prolonged drug release (from 17 to 19 days). MTT assay indicates that samples show no cytotoxicity, and combination of GO nanoparticles with gelatin coating could highly promote MG63 cell proliferation. Soaking the samples in SBF solution after 3 and 7 days demonstrates that hydroxy apatite crystals were deposited on the TON surface with GO-gelatin coating more than surface of TON with gelatin. Moreover, based on the results of disc diffusion assay, both samples (loaded with Vancomycin and coated with gelatin and gelatin-GO) with the inhibition zones equaled to 20 mm show effective antibacterial properties against S. aureus. The evidence demonstrates that titania nanotube loaded with vancomycin and coated with gelatin-GO has a great potential for general applicability to the orthopedic implant field.

How Effective are Nano-Based Dressings in Diabetic Wound Healing? A Comprehensive Review of Literature

Chronic wound caused by diabetes is an important cause of disability and seriously affects the quality of life of patients. Therefore, it is of great clinical significance to develop a wound dressing that can accelerate the healing of diabetic wounds. Nanoparticles have great advantages in promoting diabetic wound healing due to their antibacterial properties, low cytotoxicity, good biocompatibility and drug delivery ability. Adding nanoparticles to the dressing matrix and using nanoparticles to deliver drugs and cytokines to promote wound healing has proven to be effective. This review will focus on the effects of diabetes on wound healing, introduce the properties, preparation methods and action mechanism of nanoparticles in wound healing, and describe the effects and application status of various nanoparticle-loaded dressings in diabetes-related chronic wound healing.

Citric Acid-Mediated Microwave-Hydrothermal Synthesis of Mesoporous F-Doped HAp Nanorods from Bio-Waste for Biocidal Implant Applications

In this current research, mesoporous nano-hydroxyapatite (HAp) and F-doped hydroxyapatite (FHAp) were effectively obtained through a citric acid-enabled microwave hydrothermal approach. Citric acid was used as a chelating and modifying agent for tuning the structure and porosity of the HAp structure. This is the first report to use citric acid as a modifier for producing mesoporous nano HAp and F-doped FHAp. The obtained samples were characterized by different analyses. The XRD data revealed that F is incorporated well into the HAp crystal structure. The crystallinity of HAp samples was improved and the unit cell volume was lowered with fluorine incorporation. Transmission electron microscopy (TEM) images of the obtained samples revealed that a nano rod-like shape was obtained. The mesoporous structures of the produced HAp samples were confirmed by Brunauer–Emmett–Teller (BET) analysis. In vivo studies performed using zebrafish and C. elegans prove the non-toxic behavior of the synthesized F doped HAp samples. The obtained samples are also analyzed for antimicrobial activity using Gram-negative and Gram-positive bacteria, which are majorly involved in implant failure. The F doped samples revealed excellent bactericidal activity. Hence, this study confirms that the non-toxic and excellent antibacterial mesoporous F doped HAp can be a useful candidate for biocidal implant application.

Fabrication of gelatin-based and Zn2+-incorporated composite hydrogel for accelerated infected wound healing

Gelatin-based hydrogels have a broad range of biomedical fields due to their biocompatibility, convenience for chemical modifications, and degradability. However, gelatin-based hydrogels present poor antibacterial ability that hinders their applications in treating infected wound healing. Herein, a series of multifunctional hydrogels (Gel@Zn) were fabricated through free-radical polymerization interaction based on gelatin methacrylate (GelMA) and dopamine methacrylate (DMA), and then immersed them into zinc nitrate solutions based on the metal coordination and ionic bonding interaction. These designed hydrogels wound dressings show strong antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) by increasing intracellular reactive oxygen species (ROS) level and changing bacterial membrane permeability. Meanwhile, the hydrogels exhibit good cytocompatibility, enhance the adhesion, proliferation, and migration of NIH-3T3 cells. Furthermore, Gel@Zn-0.08 (0.08 ​M Zn2+ immersed with Gel sample) presents a good balance between antibacterial effect, cell viability, and hemolytic property. Compared with 3 ​M commercial dressings, Gel@Zn-0.04, and Gel@Zn-0.16, the Gel@Zn-0.08 could significantly improve the healing process of S. aureus-infected full-thickness wounds via restrained the inflammatory responses, enhanced epidermis and granulation tissue information, and stimulated angiogenesis. Our study indicates that the Zn-incorporated hydrogels are promising bioactive materials as wound dressings for infected full-thickness wound healing and skin regeneration.