In vitroandin vivoinvestigational studies of a nanocomposite-hydrogel-based dressing with a silver-coated chitosan wafer for full-thickness skin wounds

Development of a Sprayable Hydrogel-Based Wound Dressing: An In Vitro Model

Hydrogel-based dressings can effectively heal wounds by providing multiple functions, such as antibacterial, anti-inflammatory, and preangiogenic bioactivities. The ability to spray the dressing is important for the rapid and effective coverage of the wound surface. In this study, we developed a sprayable hydrogel-based wound dressing using naturally derived materials: hyaluronic acid and gelatin. We introduced methacrylate groups (HAMA and GelMA) to these materials to enable controllable photocrosslinking and form a stable hydrogel on the wound surface. To achieve sprayability, we evaluated the concentration of GelMA within a range of 5-15% (w/v) and then incorporated 1% (w/v) HAMA. Additionally, we incorporated calcium peroxide into the hydrogel at concentrations ranging from 0 to 12 mg/mL to provide self-oxygenation and antibacterial properties. The results showed that the composite hydrogels were sprayable and could provide oxygen for up to two weeks. The released oxygen relieved metabolic stress in fibroblasts and reduced cell death under hypoxia in in vitro culture. Furthermore, calcium peroxide added antibacterial properties to the wound dressing. In conclusion, the developed sprayable hydrogel dressing has the potential to be advantageous for wound healing due to its practical and conformable application, as well as its self-oxygenating and antibacterial functions.

A Review of Metal Nanoparticles Embedded in Hydrogel Scaffolds for Wound Healing In Vivo

An evolving field, nanotechnology has made its mark in the fields of nanoscience, nanoparticles, nanomaterials, and nanomedicine. Specifically, metal nanoparticles have garnered attention for their diverse use and applicability to dressings for wound healing due to their antimicrobial properties. Given their convenient integration into wound dressings, there has been increasing focus dedicated to investigating the physical, mechanical, and biological characteristics of these nanoparticles as well as their incorporation into biocomposite materials, such as hydrogel scaffolds for use in lieu of antibiotics as well as to accelerate and ameliorate healing. Though rigorously tested and applied in both medical and non-medical applications, further investigations have not been carried out to bring metal nanoparticle-hydrogel composites into clinical practice. In this review, we provide an up-to-date, comprehensive review of advancements in the field, with emphasis on implications on wound healing in in vivo experiments.

Therapeutic applications of nanobiotechnology

Nanobiotechnology, as a novel and more specialized branch of science, has provided a number of nanostructures such as nanoparticles, by utilizing the methods, techniques, and protocols of other branches of science. Due to the unique features and physiobiological characteristics, these nanostructures or nanocarriers have provided vast methods and therapeutic techniques, against microbial infections and cancers and for tissue regeneration, tissue engineering, and immunotherapies, and for gene therapies, through drug delivery systems. However, reduced carrying capacity, abrupt and non-targeted delivery, and solubility of therapeutic agents, can affect the therapeutic applications of these biotechnological products. In this article, we explored and discussed the prominent nanobiotechnological methods and products such as nanocarriers, highlighted the features and challenges associated with these products, and attempted to conclude if available nanostructures offer any scope of improvement or enhancement. We aimed to identify and emphasize the nanobiotechnological methods and products, with greater prospect and capacity for therapeutic improvements and enhancements. We found that novel nanocarriers and nanostructures, such as nanocomposites, micelles, hydrogels, microneedles, and artificial cells, can address the associated challenges and inherited drawbacks, with help of conjugations, sustained and stimuli-responsive release, ligand binding, and targeted delivery. We recommend that nanobiotechnology, despite having few challenges and drawbacks, offers immense opportunities that can be harnessed in delivering quality therapeutics with precision and prediction. We also recommend that, by exploring the branched domains more rigorously, bottlenecks and obstacles can also be addressed and resolved in return.

Topical formulation containing chitosan-chamomile microparticles in cutaneous wound healing in rats

Objective: The aim of this research was to evaluate the efficacy of a topical formulation containing chitosan-chamomile microparticles in cutaneous healing in rats. Method: Male Wistar rats (n=57) were randomly distributed into three groups: treatment; vehicle; and control. Evaluations were performed on days 2, 7 and 14 after the surgical procedure using skin lesion photography, and histological and biochemical analyses. Results: The results showed that there was no difference in the healing index and in the histological analysis of the inflammatory infiltrate among groups. Fibrogenesis was more significant in the group treated with the test formulation at day 7, and angiogenesis was greater in the vehicle and chamomile groups at day 2. The quantification of hydroxyproline showed a higher amount of collagen in the group treated with chamomile, mainly at day 14, although the histological quantification of collagen showed no difference between the groups. Conclusion: From the results of this study, it can be concluded that the formulation, although it had no effect on the healing time, improved the quality of the cicatricial tissue formed with a greater quantity of fibroblasts and collagen.

Topical formulation containing chitosan-chamomile microparticles in cutaneous wound healing in rats

Objective: The aim of this research was to evaluate the efficacy of a topical formulation containing chitosan-chamomile microparticles in cutaneous healing in rats. Method: Male Wistar rats (n=57) were randomly distributed into three groups: treatment; vehicle; and control. Evaluations were performed on days 2, 7 and 14 after the surgical procedure using skin lesion photography, and histological and biochemical analyses. Results: The results showed that there was no difference in the healing index and in the histological analysis of the inflammatory infiltrate among groups. Fibrogenesis was more significant in the group treated with the test formulation at day 7, and angiogenesis was greater in the vehicle and chamomile groups at day 2. The quantification of hydroxyproline showed a higher amount of collagen in the group treated with chamomile, mainly at day 14, although the histological quantification of collagen showed no difference between the groups. Conclusion: From the results of this study, it can be concluded that the formulation, although it had no effect on the healing time, improved the quality of the cicatricial tissue formed with a greater quantity of fibroblasts and collagen.

New skin tissue engineering scaffold with sulfated silk fibroin/chitosan/hydroxyapatite and its application

Repairing skin wounds has always been challenging in clinical practice. The new skin tissue engineering scaffold provides innovative ways to address these challenges with a good chance of success because of its stable mechanical properties, biodegradability, and antibacterial properties. This paper presents the fabrication and evaluation of a three-dimensional composite scaffold made with sulfated silk fibroin, chitosan, and hydroxyapatite (SSF/CS/HAP). An electron microscope shows that the scaffold has an aperture of 15-20 μm, while an absorption performance test shows that its expansion index reaches 779%. The co-culture of L929 cells and the CCK-8 experiments demonstrated good cell compatibility and low scaffold cytotoxicity, respectively. Meanwhile, in vivo experiments demonstrate that rats with SSF/CS/HAP scaffold-treated neck wounds heal faster. In the wound skin tissue of the SSF/CS/HAP scaffold group, immunohistochemistry indicates a more rapid and mature development of hair follicles. This study successfully developed a novel skin tissue engineering scaffold material with high moisture retention, high tissue compatibility, and low cytotoxicity, demonstrating its ability to improve wound repair with promising potential for tissue engineering applications.

Hydrogel Dressing Containing Basic Fibroblast Growth Factor Accelerating Chronic Wound Healing in Aged Mouse Model

Due to the decreasing self-repairing ability, elder people are easier to form chronic wounds and suffer from slow and difficult wound healing. It is desirable to develop a novel wound dressing that can accelerate chronic wound healing in elderly subjects to decrease the pain of patients and save medical resources. In this work, Heparin and basic fibroblast growth factor(bFGF) were dissolved in the mixing solution of 4-arm acrylated polyethylene glycol and dithiothreitol to form hydrogel dressing in vitro at room temperature without any catalysts, which is convenient and easy to handle in clinic application. In vitro re-lease test shows the bFGF could be continuously released for at least 7 days, whereas the dressing surface integrity maintained for 3 days degradation in PBS solution. Three groups of treatments including bFGF-Gel, bFGF-Sol and control without any treatment were applied on the full-thickness wound on the 22 months old mice back. The wound closure rate and histological and immunohistochemical staining all illustrated that bFGF-Gel displayed a better wound healing effect than the other two groups. Thus, as-prepared hydrogel dressing seems supe-rior to current clinical treatment and more effective in elderly subjects, which shows promising potential to be applied in the clinic.

Characterization of a novel semi-interpenetrating hydrogel network fabricated by polyethylene glycol diacrylate/polyvinyl alcohol/tragacanth gum as a wound dressing

In this research, a novel semi-interpenetrating hydrogel network comprised of polyethylene glycol diacrylate (PEGDA)/polyvinyl alcohol (PVA)/tragacanth gum (TG) with adaptable mechanical, biological, and physical characteristics was fabricated for wound healing purposes. The chemical structure of the films and the surface morphology were examined by FTIR and SEM, respectively. In addition, swelling ratio, mechanical characteristics, water vapor transmission rate (WVTR), gel fraction, and degradability of the hydrogels were assessed. To evaluate their cytocompatibility, MTT assay and cell attachment studies were performed. The FTIR results showed that the vinyl peaks were eliminated during crosslinking between PEGDA chains. The results also showed that incorporating PVA into the networks increases the swelling ration and decreases the porosity. Furthermore, as the ratio of PEGDA to PVA increased, WVTR ratio, cell adhesion, and elongation of the networks increased. It was also found that, when the amount of PEGDA reduced, degradation rate of the networks decreased. The results verified the non-toxic nature of PEGDA/PVA/TG hydrogel networks. Finally, the antibacterial results demonstrated that the highest antibacterial activities against bacterial pathogens is related to the TG-containing film. Therefore, PEGDA/PVA/TG hydrogel networks can be favorable wound dressings.

An On-Demand Dissoluble Chitosan Hydrogel Containing Dynamic Diselenide Bond

A new kind of on-demand dissolution hydrogel is successfully synthesized by modification of chitosan using γ-selenobutyrolactone. The chitosan hydrogel with different selenium contents is formed by ring opening of γ-selenobutyrolactone with the amines of D-glucosamine units on the chitosan backbone. The structure of the hydrogel was confirmed by 1H NMR, XRD and XPS. Its physical and biological properties were evaluated by rheology characterization, degradation tests and cytotoxicity test. The hydrogel showed excellent biocompatibility and good degradation properties under oxidation or reduction conditions. All the evidence demonstrated that this type of material has good prospects for dressing applications.

Scar free healing of full thickness diabetic wounds: A unique combination of silver nanoparticles as antimicrobial agent, calcium alginate nanoparticles as hemostatic agent, fresh blood as nutrient/growth factor supplier and chitosan as base matrix

Healing of diabetic wounds present a big challenge due to insufficient vascular supply and bacterial infection. We developed chitosan based biodegradable polymeric hydrogel containing silver nanoparticles (AgNPs) as antimicrobial agent and calcium alginate nanoparticles (Ca-AlgNps) as hemostatic agent to address this problem. The prepared Chitosan/Ca-AlgNps/AgNPs hydrogel showed broad spectrum antimicrobial properties against both Gram negative (E. coli, P. aeruginosa) and Gram positive (B. subtilis, S. aureus) bacteria. Taken into account the blood as a vital material containing various circulatory fibrocytes, growth factors, cytokines, platelets and macrophages etc., we incorporated the fresh blood of the same animal to the prepared Chitosan/Ca-Alg Nps/AgNPs hydrogel. In-vivo animal studies of Chitosan/Ca-AlgNps/AgNPs hydrogel and blood mixed Chitosan/Ca-AlgNps/AgNPs hydrogel exhibit 83.5 ± 4.4% and 99.8 ± 2.0% closure of wound respectively, on day 15 as compared to 41.5 ± 3.2% in diabetic control and 60.3 ± 2.2% in commercially available wound healing cream, Silverex Heal. The incorporation of fresh blood to the prepared hydrogel has advantage in terms of supplying growth factors, platelets, circulatory fibrocytes and cytokines which further enhanced the wound healing mechanism in diabetic rats. This work opens a novel idea to formulate hydrogels based dressings for diabetic wound healing.

Antibacterial Zwitterionic Polyelectrolyte Hydrogel Adhesives with Adhesion Strength Mediated by Electrostatic Mismatch

Biotissue adhesives and antibacterial materials have great potential applications in wound dressing, implantable devices, and bioelectronics. In this study, stretchable tissue adhesive hydrogels with intrinsic antibacterial properties have been demonstrated by copolymerizing zwitterionic monomers with ionic monomers. The hydrogels are stretchable to about 900% strain and show a modulus of 4-9 kPa. The zwitterionic moieties provide strong dipole-dipole interaction, electrostatic interaction, and hydrogen bonding with the skin surface, and thus show adhesion strength values of 1-4 kPa to skin. Meanwhile, the copolymerized cationic or anionic monomers break the intrinsic electrostatic stoichiometry of the zwitterionic units and thus mediate the electrostatic interactions and the adhesion strength with the surface. The stretchable hydrogels form a robust and compliant (due to low modulus and stretchability) adhesive to skin, rubber, glass, and plastics, and could be repeatedly peeled-off and readhered to the skin. Moreover, the abundant quaternary ammonium (QA) groups in the zwitterionic moieties and the added QA groups endow it outstanding antibacterial properties (>99%). These stretchable tissue adhesive antibacterial hydrogels are promising for wound dressings and implantable devices.

Application status and technical analysis of chitosan-based medical dressings: a review

Chitosan has wide applications in the field of medical dressings due to its good biomedical properties. This review provides the application status and technical analysis of chitosan medical dressings. First, we introduce the source and chemical structure of chitosan. Then, we investigate the mechanism of chitosan showing different medical properties. We also show the application of supramolecular chitosan-based hydrogels in the dressing field and the formulation optimization and the preparation technology of chitosan dressings for fabricating chitosan-based dressings with various morphologies and medical functions. After that, we introduce the research process of the modification method of chitosan dressings including single modification, blending modification, crosslinking modification, etc. Finally, based on the study of the medical effects of chitosan dressings, we analyze the existing problems in the preparation process and propose corresponding solutions from the aspects of the morphology, clinical feedback effect, and future development trends. This paper can provide a reference for further studies of skin tissue engineering and the development of new chitosan medical dressings.

Chitosan has wide applications in the field of medical dressings due to its good biomedical properties.

Antibiotic Delivery Strategies to Treat Skin Infections When Innate Antimicrobial Defense Fails

The epidermal skin barrier protects the body from a host of daily challenges, providing protection against mechanical insults and the absorption of chemicals and xenobiotics. In addition to the physical barrier, the epidermis also presents an innate defense against microbial overgrowth. This is achieved through the presence of a diverse collection of microorganisms on the skin (the "microbiota") that maintain a delicate balance with the host and play a significant role in overall human health. When the skin is wounded, the local tissue with a compromised barrier can become colonized and ultimately infected if bacterial growth overcomes the host response. Wound infections present an immense burden in healthcare costs and decreased quality of life for patients, and treatment becomes increasingly important because of the negative impact that infection has on slowing the rate of wound healing. In this review, we discuss specific challenges of treating wound infections and the advances in drug delivery platforms and formulations that are under development to improve topical delivery of antimicrobial treatments.

Safety of a formulation containing chitosan microparticles with chamomile: blind controlled clinical trial

OBJECTIVE

to evaluate the safety of a topical formulation containing chamomile microparticles coated with chitosan in the skin of healthy participants.

METHOD

phase I blind, controlled, non-randomized, single-dose clinical trial with control for skin, base formulation, and formulation with microparticles. The variables analyzed were irritation and hydration by the Wilcoxon and Kruskall-Wallis tests.

RESULTS

the study started with 35 participants with a mean age of 26.3 years. Of these, 30 (85.71%) were female, 29 (82.90%) were white skinned and 32 (91.40%) had no previous pathologies. One participant was removed from the study reporting erythema at the site of application, and four other participants for not attending the last evaluation. In the 30 participants who completed the study, the tested formulation did not cause erythema, peeling, burning, pruritus or pain; there was an improvement in cutaneous hydration in the site of application of the formulation with microparticles. In the evaluation of the barrier function, there was an increase in transepidermal water loss in all sites.

CONCLUSION

the formulation with chamomile microparticles is safe for topical use, not causing irritation and improving skin hydration over four weeks of use. Its effects on barrier function need further investigation. No. RBR-3h78kz in the Brazilian Registry of Clinical Trials (ReBEC).

Treatment Strategies for Infected Wounds

The treatment of skin wounds is a key research domain owing to the important functional and aesthetic role of this tissue. When the skin is impaired, bacteria can soon infiltrate into underlying tissues which can lead to life-threatening infections. Consequently, effective treatments are necessary to deal with such pathological conditions. Recently, wound dressings loaded with antimicrobial agents have emerged as viable options to reduce wound bacterial colonization and infection, in order to improve the healing process. In this paper, we present an overview of the most prominent antibiotic-embedded wound dressings, as well as the limitations of their use. A promising, but still an underrated group of potential antibacterial agents that can be integrated into wound dressings are natural products, especially essential oils. Some of the most commonly used essential oils against multidrug-resistant microorganisms, such as tea tree, St. John's Wort, lavender and oregano, together with their incorporation into wound dressings are presented. In addition, another natural product that exhibits encouraging antibacterial activity is honey. We highlight recent results of several studies carried out by researchers from different regions of the world on wound dressings impregnated with honey, with a special emphasis on Manuka honey. Finally, we highlight recent advances in using nanoparticles as platforms to increase the effect of pharmaceutical formulations aimed at wound healing. Silver, gold, and zinc nanoparticles alone or functionalized with diverse antimicrobial compounds have been integrated into wound dressings and demonstrated therapeutic effects on wounds.

Biomedical Potential of Ultrafine Ag Nanoparticles Coated on Poly (Gamma-Glutamic Acid) Hydrogel with Special Reference to Wound Healing

In wound care management, the prevention of wound infection and the retention of an appropriate level of moisture are two major challenges. Therefore, designing an excellent antibacterial hydrogel with a suitable water-adsorbing capacity is very important to improve the development of wound dressings. In this paper, a novel silver nanoparticles/poly (gamma-glutamic acid) (γ-PGA) composite dressing was prepared for biomedical applications. The promoted wound-healing ability of the hydrogels were systematically evaluated with the aim of attaining a novel and effective wound dressing. A diffusion study showed that hydrogels can continuously release antibacterial factors (Ag). Hydrogels contain a high percentage of water, providing an ideal moist environment for tissue regeneration, while also preventing contraction of the wound. Moreover, an in vivo, wound-healing model evaluation of artificial wounds in mice indicated that silver/γ-PGA hydrogels could significantly promote wound healing. Histological examination revealed that hydrogels can successfully help to reconstruct intact epidermis and collagen deposition during 14 days of impaired wound healing. Overall, this research could shed new light on the design of antibacterial silver/γ-PGA hydrogels with potential applications in wound dressing.

Antibacterial Hydrogels

Antibacterial materials are recognized as important biomaterials due to their effective inhibition of bacterial infections. Hydrogels are 3D polymer networks crosslinked by either physical interactions or covalent bonds. Currently, hydrogels with an antibacterial function are a main focus in biomedical research. Many advanced antibacterial hydrogels are developed, each possessing unique qualities, namely high water swellability, high oxygen permeability, improved biocompatibility, ease of loading and releasing drugs, and structural diversity. Here, an overview of the structures, performances, mechanisms of action, loading and release behaviors, and applications of various antibacterial hydrogel formulations is provided. Furthermore, the prospects in biomedical research and clinical applications are predicted.

Inorganic Nanomaterials for Soft Tissue Repair and Regeneration

Inorganic nanomaterials have witnessed significant advances in areas of medicine including cancer therapy, imaging, and drug delivery, but their use in soft tissue repair and regeneration is in its infancy. Metallic, ceramic, and carbon allotrope nanoparticles have shown promise in facilitating tissue repair and regeneration. Inorganic nanomaterials have been employed to improve stem cell engraftment in cellular therapy, material mechanical stability in tissue repair, electrical conductivity in nerve and cardiac regeneration, adhesion strength in tissue approximation, and antibacterial capacity in wound dressings. These nanomaterials have also been used to improve or replace common surgical materials and restore functionality to damaged tissue. We provide a comprehensive overview of inorganic nanomaterials in tissue repair and regeneration, and discuss their promise and limitations for eventual translation to the clinic.

A functional chitosan-based hydrogel as a wound dressing and drug delivery system in the treatment of wound healing

Functional active wound dressings are expected to provide a moist wound environment, offer protection from secondary infections, remove wound exudate and accelerate tissue regeneration, as well as to improve the efficiency of wound healing. Chitosan-based hydrogels are considered as ideal materials for enhancing wound healing owing to their biodegradable, biocompatible, non-toxic, antimicrobial, biologically adhesive, biological activity and hemostatic effects. Chitosan-based hydrogels have been demonstrated to promote wound healing at different wound healing stages, and also can alleviate the factors against wound healing (such as excessive inflammatory and chronic wound infection). The unique biological properties of a chitosan-based hydrogel enable it to serve as both a wound dressing and as a drug delivery system (DDS) to deliver antibacterial agents, growth factors, stem cells and so on, which could further accelerate wound healing. For various kinds of wounds, chitosan-based hydrogels are able to promote the effectiveness of wound healing by modifying or combining with other polymers, and carrying different types of active substances. In this review, we will take a close look at the application of chitosan-based hydrogels in wound dressings and DDS to enhance wound healing.

Preparation of Copolymer-Based Nanoparticles with Broad-Spectrum Antimicrobial Activity

Polyacrylate and guanidine-based nanoparticles which involve acrylate monomers and glycidyl methacrylate modified oligo-guanidine were prepared by a seeded semi-continuous emulsion polymerization. The results from transmission electron microscope and dynamic light scattering measurements showed that the nanoparticles were spherical in shape and the particle size was in the range of 80⁻130 nm. Antimicrobial experiments were performed with two types of bacteria, Gram-negative (Escherichia coli, ATCC 8739) and Gram-positive (Staphylococcus aureus, ATCC 6538). The as-synthesized cationic nanoparticles exhibited effective antimicrobial activities on Escherichia coli and Staphylococcus aureus with the minimal inhibitory concentrations at 8 μg/mL and 4 μg/mL, respectively. The mechanism of action of the resulted nanoparticles against these bacteria was revealed by the scanning electron microscopic observation. In addition, the films consisting of latex nanoparticles are non-leaching antimicrobial materials with excellent antimicrobial activity, which indicates the polymers could preserve their antimicrobial activity for long-term effectiveness.

Electrical signals triggered controllable formation of calcium-alginate film for wound treatment

Wound dressings play important roles in the management of wounds, and calcium cross-linked alginate (Ca²⁺-Alg) is a commonly used hydrogel that is adapted for wound treatment. However, conventional methods for fabricating Ca²⁺-Alg hydrogels can be tedious and difficult to control because of the rapid Ca²⁺-induced gelation of alginate. In this study, An electrodeposition method was used to rapidly and controllably fabricate Ca²⁺-Alg films for wound treatment. Several measures of film growth (e.g., thickness and mass) are shown to linearly correlate to the imposed charge transfer at the electrode. Similarly, this charge transfer was also observed to control important physicochemical wound healing properties such as water uptake and retention capacity. Furthermore, a wound healing animal test was performed to evaluate the performance of this electro-fabricated calcium alginate film for wound treatment. This in vivo study demonstrated that wounds dressed with an electro-fabricated Ca²⁺-Alg film closed faster than that of untreated wounds. Further, the new dermis tissue that formed was composed of reorganized and stratified epithelial layer, with fully developed connective tissue, hair follicle, sebaceous glands as well as aligned collagen. Therefore, our study indicates that this electrofabrication method for the rapid and controlled preparation of alginate film could provide exciting opportunities for wound treatment. More broadly, this study demonstrates the potential of electrochemistry for the fabrication of high performance polymeric materials. Here we report a rapid and controllable fabrication of free-standing alginate films by coupling anodic electrodeposition with subsequent peeling of deposited materials for wound dressing.

A versatile approach towards multi-functional surfaces via covalently attaching hydrogel thin layers

In this study, a robust and straightforward method to covalently attach multi-functional hydrogel thin layers onto substrates was provided. In our strategy, double bonds were firstly introduced onto substrates to provide anchoring points for hydrogel layers, and then hydrogel thin layers were prepared via surface cross-linking copolymerization of the immobilized double bonds with functional monomers. Sulfobetaine methacrylate (SBMA), sodium allysulfonate (SAS), and methyl acryloyloxygen ethyl trimethyl ammonium chloride (METAC) were selected as functional monomers to form hydrogel layers onto polyether sulfone (PES) membrane surfaces, respectively. The thickness of the formed hydrogel layers could be controlled, and the layers showed excellent long-term stability. The PSBMA hydrogel layer exhibited superior antifouling property demonstrated by undetectable protein adsorption and excellent bacteria resistant property; after attaching PSAS hydrogel layer, the membrane showed incoagulable surface property when contacting with blood confirmed by the activated partial thromboplastin time (APTT) value exceeding 600s; while, the PMETAC hydrogel thin layer could effectively kill attached bacteria. The proposed method provides a new platform to directly modify material surfaces with desired properties, and thus has great potential to be widely used in designing materials for blood purification, drug delivery, wound dressing, and intelligent biosensors.