Multifunctional Copper-Containing Carboxymethyl Chitosan/Alginate Scaffolds for Eradicating Clinical Bacterial Infection and Promoting Bone Formation

Effects of Diatomite Contents on Microstructure, Microhardness, Bioactivity and Biocompatibility of Gradient Bioceramic Coating Prepared by Laser Cladding

Biometallic materials are widely used in medicine because of excellent mechanical properties. However, biometallic materials are limited in the application of biomaterials due to their lack of bioactivity. To solve this problem, a gradient bioceramic coating doped with diatomite (DE) was successfully fabricated on the surface of Ti6Al4V alloy by using the broadband-laser cladding process to improve the bioactivity of metal materials. As well as the DE contents on the microstructure, microhardness, bioactivity and biocompatibility were investigated. The experimental results demonstrate that the addition of moderate amounts of DE is effective in reducing the number of cracks. The X-ray diffraction (XRD) results reveal that the bioceramic coating doped with DE mainly consists of CaTiO3, hydroxyapatite (HA), tricalcium phosphate (TCP) and silicate, and that the amount of HA and TCP in the coating reached maximum when the bioceramic coating was doped with 10wt% DE. The bioceramic coating doped with 10wt% DE has favorable ability to deposit bone-like apatite. These results indicate that the addition of DE can improve cracking sensibility, bioactivity and biocompatibility of the coating.

Chitosan-Based Biomaterial Scaffolds for the Repair of Infected Bone Defects

The treatment of infected bone defects includes infection control and repair of the bone defect. The development of biomaterials with anti-infection and osteogenic ability provides a promising strategy for the repair of infected bone defects. Owing to its antibacterial properties, chitosan (an emerging natural polymer) has been widely studied in bone tissue engineering. Moreover, it has been shown that chitosan promotes the adhesion and proliferation of osteoblast-related cells, and can serve as an ideal carrier for bone-promoting substances. In this review, the specific molecular mechanisms underlying the antibacterial effects of chitosan and its ability to promote bone repair are discussed. Furthermore, the properties of several kinds of functionalized chitosan are analyzed and compared with those of pure chitosan. The latest research on the combination of chitosan with different types of functionalized materials and biomolecules for the treatment of infected bone defects is also summarized. Finally, the current shortcomings of chitosan-based biomaterials for the treatment of infected bone defects and future research directions are discussed. This review provides a theoretical basis and advanced design strategies for the use of chitosan-based biomaterials in the treatment of infected bone defects.

Surface Modification of Poly(ether ether ketone) by Simple Chemical Grafting of Strontium Chondroitin Sulfate to Improve its Anti-Inflammation, Angiogenesis, Osteogenic Properties

Besides inducing osteogenic differentiation, the surface modification of poly(ether ether ketone) (PEEK) is highly expected to improve its angiogenic activity and reduce the inflammatory response in the surrounding tissue. Herein, strontium chondroitin sulfate is first attempted to be introduced into the surface of sulfonated PEEK (SPEEK-CS@Sr) based on the Schiff base reaction between PEEK and ethylenediamine (EDA) and the amidation reaction between EDA and chondroitin sulfate (CS). The surface characteristics of SPEEK-CS@Sr implant are systematically investigated, and its biological properties in vitro and in vivo are also evaluated. The results show that the surface of SPEEK-CS@Sr implant exhibits a 3D microporous structure and good hydrophilicity, and can steadily release Sr ions. Importantly, the SPEEK-CS@Sr not only displays excellent biocompatibility, but also can remarkably promote cell adhesion and spread, improve osteogenic activity and angiogenic activity, and reduce the inflammatory response compared to the original PEEK. Therefore, this study presents the surface modification of PEEK material by simple chemical grafting of strontium chondroitin sulfate to improve its angiogenesis, anti-inflammation, and osteogenic properties, and the as-fabricated SPEEK-CS@Sr has the potential to serve as a promising orthopedic implant in bone tissue engineering.

Engineered Cu-PEN Composites at the Nanoscale: Preparation and Characterisation

As polymeric materials are already used in many industries, the range of their applications is constantly expanding. Therefore, their preparation procedures and the resulting properties require considerable attention. In this work, we designed the surface of polyethylene naphthalate (PEN) introducing copper nanowires. The surface of PEN was transformed into coherent ripple patterns by treatment with a KrF excimer laser. Then, Cu deposition onto nanostructured surfaces by a vacuum evaporation technique was accomplished, giving rise to nanowires. The morphology of the prepared structures was investigated by atomic force microscopy and scanning electron microscopy. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy revealed the distribution of Cu in the nanowires and their gradual oxidation. The optical properties of the Cu nanowires were measured by UV-Vis spectroscopy. The sessile drop method revealed the hydrophobic character of the Cu/PEN surface, which is important for further studies of biological responses. Our study suggests that a combination of laser surface texturing and vacuum evaporation can be an effective and simple method for the preparation of a Cu/polymer nanocomposite with potential exploitation in bioapplications; however, it should be borne in mind that significant post-deposition oxidation of the Cu nanowire occurs, which may open up new strategies for further biological applications.

Development and characterization of cannabidiol-loaded alginate copper hydrogel for repairing open bone defects in vitro

The clinical treatment of open bone defects caused by accidental bone trauma, bone tumors, bone diseases and bone infections is challenging. In this study, we designed and fabricated a multifunctional alginate-based hydrogel that contains cannabidiol (CBD), SA@Cu/CBD hydrogel, for repairing open bone defects. The results of physicochemical characterization showed that the SA@Cu/CBD hydrogel was successfully prepared and showed a suitable swelling ratio, high thermal stability, and stable mechanical properties. In vitro evaluation of antibacterial activity indicated that more than 90% of S. aureus and E. coli were inhibited compared to the control group. The ALP activity assay showed that the ALP expression level of MC3T3-E1cells in SA@Cu/CBD hydrogel was approximately 2-fold higher than that in the control group on day 7 and 14. Additionally, compared to the control group, the level of mineralized deposits in SA@Cu/CBD hydrogel was also improved by about 2 times on day 14. The PCR results indicated the mRNA expression levels of osteogenic markers (ALP, Col1α1, OCN, and RUNX2 genes) and angiogenic markers (EGFL6 and VEGF genes) in SA@Cu/CBD hydrogel were significantly upregulated compared to that in the control group, and the mRNA expression levels of critical inflammatory cytokines (TNF-α and IL-1β) in the SA@Cu/CBD hydrogel were significantly down-regulated compared to that in SA@Cu hydrogel. Taken together, these results demonstrated that the SA@Cu/CBD hydrogel showed significantly anti-bacterial, anti-inflammation, angiogenic and osteogenic activities in vitro studies. Thus, SA@Cu/CBD hydrogels may be a promising candidate in repairing open bone defects.

A comparative study of the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in rabbits

BACKGROUND

Autologous platelet concentrate has been widely used to encourage the regeneration of hard and soft tissues. Up to now, there are three generations of autologous platelet concentrates. Many studies have shown that the three autologous concentrates have different effects, but the specific diversities have not been studied. The purpose of this study was to explore and compare the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in New Zealand rabbits.

METHODS

A total of 24 healthy male New Zealand white rabbits aged 8-12 weeks were selected. The experimental animals were randomly divided into four groups: three experimental groups were respectively implanted with PPP, CGF and PRF gel after bilateral mandibular anterior teeth were extracted, and the control group did not implant any material. The alveolar bone of the mandibular anterior region was taken at 2, 4 and 8 weeks after operation. The height and width of the extraction wound were detected by CBCT, the growth of the new bone was observed by HE and Masson staining, and the expression of osteogenic genes was detected by real-time PCR. Data were analyzed using IBM SPSS statistical package 22.0.

RESULTS

The radiological results showed that alveolar bone resorption in all groups gradually increased over time. However, the experimental groups showed lower amounts of bone resorption. The histological results showed that new bone formation was observed in all groups. Over time, the new bone trabeculae of the CGF group became closely aligned while those in the PPP and PRF groups remained scattered. PCR results showed that the expression of BMP-2 and ALP was higher in the experimental groups than the control group.

CONCLUSION

In conclusion, the application of PRF, CGF and PPP in tooth extraction sockets effectively promoted bone regeneration. CGF showed more effective bone induction and tissue regeneration ability in the long term.

Surface-Decorated Graphene Oxide Sheets with Copper Nanoderivatives for Bone Regeneration: An In Vitro and In Vivo Study Regarding Molecular Mechanisms, Osteogenesis, and Anti-infection Potential

It has been previously reported that graphene oxide/copper nanoderivative (GO/Cu)-incorporated chitosan/hyaluronic acid scaffolds might be promising wound dressings for the management of infected wound healing. The aim of the present research is to deeply explore the potential antimicrobial mechanisms and synergistic osteogenic activity, as well as the in vivo anti-infective behavior of GO/Cu nanocomposites, making them possible candidates for establishing implantable biomaterials for the repair of infected bone defects. The antibacterial mechanisms of the nanocomposites were explored through the examination of membrane integrity, oxidative stress, and metabolic enzyme activities. Then, the cytocompatibility with bone mesenchymal stem cells (rBMSCs) and osteogenic potential were confirmed, and a subcutaneous bacterial infection model in rats was also established to verify the in vivo anti-infective property and biosafety of the nanocomposites. It was found that leakage of adenosine triphosphate, proteins, and reducing sugars from the bacterial cells, indicative of damaged permeability of bacterial membranes, and promoted production of reactive oxygen species and disordered metabolic enzyme activities in response to oxidative stress were possible molecular mechanisms responsible for the synergistic antibacterial effects of the GO/Cu nanocomposites. Additionally, good cytocompatibility with rBMSCs and promoted osteogenic differentiation were found in GO/Cu nanocomposites (mass ratio = 2:1), which also demonstrated satisfactory in vivo anti-infective performance, reduced inflammation, and acceptable biosafety. Based on our results, damaged bacterial membranes, increased ROS production, and disorders of crucial enzyme metabolism were the main antibacterial mechanisms involved in the bacterium-killing events caused by the GO/Cu nanocomposites, which also showed enhanced osteogenic activity, in vivo anti-infective capability, and acceptable cytocompatibility and biosafety. Therefore, GO/Cu (2:1) nanocomposites are a potential strategy for improving the biological performance of current bone substitutes used for combating bacterial-contaminated bone defects.

Bioactive Chitosan-Based Organometallic Scaffolds for Tissue Engineering and Regeneration

Captivating achievements in developing advanced hybrid biostructures through integrating natural biopolymers with inorganic materials (e.g., metals and metalloids) have paved the way towards the application of bioactive organometallic scaffolds (OMSs) in tissue engineering and regenerative medicine (TERM). Of various biopolymers, chitosan (CS) has been used widely for the development of bioactive OMSs, in large part due to its unique characteristics (e.g., biocompatibility, biodegradability, surface chemistry, and functionalization potential). In integration with inorganic elements, CS has been used to engineer advanced biomimetic matrices to accommodate both embedded cells and drug molecules and serve as scaffolds in TERM. The use of the CS-based OMSs is envisioned to provide a new pragmatic potential in TERM and even in precision medicine. In this review, we aim to elaborate on recent achievements in a variety of CS/metal, CS/metalloid hybrid scaffolds, and discuss their applications in TERM. We also provide comprehensive insights into the formulation, surface modification, characterization, biocompatibility, and cytotoxicity of different types of CS-based OMSs.

An injectable gellan gum-based hydrogel that inhibits Staphylococcus aureus for infected bone defect repair

The treatment of infected bone defects in complex anatomical structures, such as oral and maxillofacial structures, remains an intractable clinical challenge. Therefore, advanced biomaterials that have excellent anti-infection activity and allow convenient delivery are needed. We fabricated an innovative injectable gellan gum (GG)-based hydrogel loaded with nanohydroxyapatite particles and chlorhexidine (nHA/CHX). The hydrogel has a porous morphology, suitable swelling ratio, and good biocompatibility. It exerts strong antibacterial activity against Staphylococcus aureus growth and biofilm formation in vitro. We successfully established an infected calvarial defect rat model. Bacterial colony numbers were significantly lower in tissues surrounding the bone in rats of the GG/nHA/CHX group after debride surgery and hydrogel implantation in the defect regions than in rats of the blank group. Rats in the GG/nHA/CHX group exhibited significantly increased new bone formation compared to those in the blank group at 4 and 8 weeks. These findings indicate that gellan gum-based hydrogel with nHA/CHX can accelerate the repair of infected bone defects.

In situ formation of a near-infrared controlled dual-antibacterial platform

An in situ formed antibacterial platform was designed for near-infrared controlled pharmacotherapy and photothermal therapy of drug-resistant bacteria.

Antibacterial approaches in tissue engineering using metal ions and nanoparticles: From mechanisms to applications

Bacterial infection of implanted scaffolds may have fatal consequences and, in combination with the emergence of multidrug bacterial resistance, the development of advanced antibacterial biomaterials and constructs is of great interest. Since decades ago, metals and their ions had been used to minimize bacterial infection risk and, more recently, metal-based nanomaterials, with improved antimicrobial properties, have been advocated as a novel and tunable alternative. A comprehensive review is provided on how metal ions and ion nanoparticles have the potential to decrease or eliminate unwanted bacteria. Antibacterial mechanisms such as oxidative stress induction, ion release and disruption of biomolecules are currently well accepted. However, the exact antimicrobial mechanisms of the discussed metal compounds remain poorly understood. The combination of different metal ions and surface decorations of nanoparticles will lead to synergistic effects and improved microbial killing, and allow to mitigate potential side effects to the host. Starting with a general overview of antibacterial mechanisms, we subsequently focus on specific metal ions such as silver, zinc, copper, iron and gold, and outline their distinct modes of action. Finally, we discuss the use of these metal ions and nanoparticles in tissue engineering to prevent implant failure.

Vanillin-bioglass cross-linked 3D porous chitosan scaffolds with strong osteopromotive and antibacterial abilities for bone tissue engineering

Chitosan scaffolds crosslinked by current methods insufficiently meet the demands of bone tissue engineering applications. We developed a novel effective crosslinking technique by using the natural and safe vanillin together with bioglass microparticles to generate an antibacterial, osteoconductive, and mechanically robust 3D porous chitosan-vanillin-bioglass (CVB) scaffold. In addition to the significantly improved mechanical properties, the CVB scaffolds had high porosity (>90%) and interconnected macroporous structures. Our data suggested that the crosslinking mainly resulted from the Schiff base reactions between the aldehydes of vanillin and amines of chitosan, together with the hydrogen and ionic bonds formed within them. Importantly, the CVB scaffolds not only showed good biocompatibility, bioactivity, and strong antibacterial ability but also significantly promoted osteoblastic differentiation, mineralization in vitro, and ectopic bone formation in vivo. Thus, the CVB scaffolds hold great promise for bone tissue engineering applications based on their robust mechanical properties, osteoconductivity, and antibacterial abilities.

Nutrient Element Decorated Polyetheretherketone Implants Steer Mitochondrial Dynamics for Boosted Diabetic Osseointegration

As a chronic metabolic disease, diabetes mellitus (DM) creates a hyperglycemic micromilieu around implants, resulting inthe high complication and failure rate of implantation because of mitochondrial dysfunction in hyperglycemia. To address the daunting issue, the authors innovatively devised and developed mitochondria-targeted orthopedic implants consisted of nutrient element coatings and polyetheretherketone (PEEK). Dual nutrient elements, in the modality of ZnO and Sr(OH)2 , are assembled onto the sulfonated PEEK surface (Zn&Sr-SPEEK). The results indicate the synergistic liberation of Zn2+ and Sr2+ from coating massacres pathogenic bacteria and dramatically facilitates cyto-activity of osteoblasts upon the hyperglycemic niche. Intriguingly, Zn&Sr-SPEEK implants are demonstrated to have a robust ability to recuperate hyperglycemia-induced mitochondrial dynamic disequilibrium and dysfunction by means of Dynamin-related protein 1 (Drp1) gene down-regulation, mitochondrial membrane potential (MMP) resurgence, and reactive oxygen species (ROS) elimination, ultimately enhancing osteogenicity of osteoblasts. In vivo evaluations utilizing diabetic rat femoral/tibia defect model at 4 and 8 weeks further confirm that nutrient element coatings substantially augment bone remodeling and osseointegration. Altogether, this study not only reveals the importance of Zn2+ and Sr2+ modulation on mitochondrial dynamics that contributes to bone formation and osseointegration, but also provides a novel orthopedic implant for diabetic patients with mitochondrial modulation capability.

Copper metal-organic framework embedded carboxymethyl chitosan-g-glutathione/polyacrylamide hydrogels for killing bacteria and promoting wound healing

Bacterial infection and its induced oxidative stress as major clinical challenge during wound healing call for an urgent response for the development of medical dressings with multi-functions, such as antioxidant and antibacterial. To meet this demand, copper metal organic framework nanoparticles (HKUST NPs) and carboxymethyl chitosan-g-glutathione (CMCs-GSH) were synthesized and characterized. By embedding HKUST NPs into PAM/CMCs-GSH hydrogel (AOH), we developed a novel hydrogel dressing (HKUST-Hs) with dual effects of antibacterial and antioxidant. The morphology, swelling behavior, oxidation resistance and antibacterial properties of HKUST-Hs were investigated as well as the slow-release behavior of copper ions. Full-thickness cutaneous wound model of rats was created to assess the promoting effect of HKUST-Hs on wound healing. We found that HKUST NPs could be well dispersed in HKUST-Hs by shielding the positive charge of copper ions, and thus copper ions released were uniformly distributed and chelated with CMCs-GSH to promote the swelling stability of HKUST-Hs. Also, HKUST-Hs exhibited good free radical scavenging ability in vitro antioxidant assay. Meanwhile, a gradient sustained-release system of copper ions was formed in HKUST-Hs owing to the inhibition of HKUST NPs to copper release and the chelation of CMCs-GSH, which effectively inhibited the explosive release of copper ions and prolonged the release period, thereby reducing cytotoxicity. In vitro antibacterial test demonstrated there was synergistic antibacterial effect between the slow-released copper ions and CMCs-GSH, which improved the antibacterial activity and antibacterial persistence of HKUST-Hs. Finally, HKUST-Hs accelerated wound healing in vivo by continuously killing bacteria and inhibiting oxidative stress.

Long-term induction of endogenous BMPs growth factor from antibacterial dual network hydrogels for fast large bone defect repair

Osteoinductive, osteoconductive, and antibacterial properties of bone repair materials play important roles in regulating the successful bone regeneration. In the present work, we developed pH-sensitive gelatin methacryloyl (GelMA)-oxidized sodium alginate (OSA) hydrogels for dual-release of gentamicin sulfate (GS) and phenamil (Phe) to enhance the antibacterial activity and to promote large bone defect repair. Controlled release of GS was achieved through physical blending with GelMA-OSA solution before photo-polymeriaztion, while Phe was encapsulated into mesoporous silicate nanoparticles (MSN) within the hydrogels. In vitro antibacterial studies against Staphylococcus aureus and Escherichia coli indicated the broad-spectrum antibacterial property. Moreover, in vitro cell tests verified the synergistically enhanced osteogenic differentiation ability. Furthermore, in vivo studies revealed that the hydrogels significantly increased new bone formation in a critical-sized mouse cranial bone defect model. In summary, the novel dual-network hydrogels with both antibacterial and osteoinductive properties showed promising potential applications in bone tissue engineering.

Ultrafast in-situ forming halloysite nanotube-doped chitosan/oxidized dextran hydrogels for hemostasis and wound repair

A series of halloysite nanotube (HNT)-doped chitosan (CS)/oxidized dextran (ODEX) adhesive hydrogels were developed through a Schiff base reaction. The resultant CS/ODEX/HNT hydrogels could not only form in situ on wounds within only 1 s when injected, but could also adapt to wounds of different shapes and depths after injection. We established four rat and rabbit hemorrhage models and demonstrated that the hydrogels are better than the clinically used gelatin sponge for reducing hemostatic time and blood loss, particularly in arterial and deep noncompressible bleeding wounds. Moreover, the natural antibacterial features of CS and ODEX provided the hydrogels with strong bacteria-killing effects. Consequently, they significantly promoted methicillin-resistant Staphylococcus aureus -infected-wound repair compared to commercial gelatin sponge and silver-alginate antibacterial wound dressing. Hence, our multifunctional hydrogels with facile preparation process and utilization procedure could potentially be used as first-aid biomaterials for rapid hemostasis and infected-wound repair in emergency injury events.

Black phosphorus incorporation modulates nanocomposite hydrogel properties and subsequent MC3T3 cell attachment, proliferation, and differentiation

A promising strategy that emerged in tissue engineering is to incorporate two-dimensional (2D) materials into polymer scaffolds, producing materials with desirable mechanical properties and surface chemistries, which also display broad biocompatibility. Black phosphorus (BP) is a 2D material that has sparked recent scientific interest due to its unique structure and electrochemical characteristics. In this study, BP nanosheets (BPNSs) were incorporated into a cross-linkable oligo[poly(ethylene glycol) fumarate] (OPF) hydrogel to produce a new nanocomposite for bone regeneration. BPNSs exhibited a controllable degradation rate coupled with the release of phosphate in vitro. MTS assay results together with live/dead images confirmed that the introduction of BPNSs into OPF hydrogels enhanced MC3T3-E1 cell proliferation. Moreover, the morphology parameters indicated better attachments of cells in the BPNSs containing group. Immunofluorescence images as well as intercellular ALP and OCN activities showed that adding a certain amount of BPNSs to OPF hydrogel could greatly improve differentiation of pre-osteoblasts on the hydrogel. Additionally, embedding black phosphorous into a neutral polymer network helped to control its cytotoxicity, with optimal cell growth observed at BP concentrations as high as 500 ppm. These results reinforced that the supplementation of OPF with BPNSs can increase the osteogenic capacity of polymer scaffolds for use in bone tissue engineering.

Facile surface functional polyetheretherketone with antibacterial and immunoregulatory activities for enhanced regeneration toward bacterium-infected bone destruction

Existing biologically inert or unmodified implants to treat infectious bone defects or osteomyelitis still cannot effectively solve bacterial infection and osseointegration. In this work, a simple co-deposition strategy was developed to modify porous polyetheretherketone (PEEK) with improved antibacterial activity and controllable immunoregulatory ability. After PEEK was treated by H₂SO₄ to obtain porous PEEK (SPEEK), the self-polymerization of dopamine was operated on SPEEK in the solution of dopamine and gentamicin sulfate (GS) to prepare polydopamine (pDA) and GS layer-modified SPEEK (labeled as SPEEK–pDA–GS). The morphology, surface property, and molecular structure of SPEEK–pDA–GS were investigated. Besides the antibacterial property of SPEEK–pDA–GS ascribed to the successful immobilization of GS, SPEEK–pDA–GS exhibited promoted osseointegration through the results of mineralization, alkaline phosphatase (ALP) levels and osteogenic gene expression. Furthermore, the evaluation of the cell proliferation suggested that SPEEK–pDA–GS possessed the biocompatibility and the immunoregulatory ability that induced macrophages to anti-inflammatory M2 phenotype. Using rat as model, in vivo results containing X-ray, μ-CT, immunohistochemistry, and pathological analysis showed the excellent healing effect of SPEEK–pDA–GS on bone defect with infection with biological safety. This work illustrates a new insight into the simple and effective modification of PEEK and other implants with antibacterial, immunoregulatory, and osseointegration abilities for clinical requirement.

Control Release of Adenosine Potentiate Osteogenic Differentiation within a Bone Integrative EGCG-g-NOCC/Collagen Composite Scaffold toward Guided Bone Regeneration in a Critical-Sized Calvarial Defect

The regeneration of critical-sized bone defects with biomimetic scaffolds remains clinically challenging due to avascular necrosis, chronic inflammation, and altered osteogenic activity. Two confounding mechanisms, efficacy manipulation, and temporal regulation dictate the scaffold's bone regenerative ability. Equally critical is the priming of the mesenchymal stromal cells (MSCs) toward lineage-specific differentiation into bone-forming osteoblast, which particularly depends on varied mechanochemical and biological cues during bone tissue regeneration. This study sought to design and develop an optimized osteogenic scaffold, adenosine/epigallocatechin gallate-N,O-carboxymethyl chitosan/collagen type I (AD/EGCG-g-NOCC@clgn I), having osteoinductive components toward swift bone regeneration in a calvarial defect BALB/c mice model. The ex vivo findings distinctly establish the pro-osteogenic potential of adenosine and EGCG, stimulating MSCs toward osteoblast differentiation with significantly increased expression of alkaline phosphatase, calcium deposits, and enhanced osteocalcin expression. Moreover, the 3D matrix recapitulates extracellular matrix (ECM) properties, provides a favorable microenvironment, structural support against mechanical stress, and acts as a reservoir for sustained release of osteoinductive molecules for cell differentiation, proliferation, and migration during matrix osteointegration observed. Evidence from in vivo experiments, micro-CT analyses, histology, and histomorphometry signify accelerated osteogenesis both qualitatively and quantitatively: effectual bone union with enhanced bone formation and new ossified tissue in 4 mm sized defects. Our results suggest that the optimized scaffold serves as an adjuvant to guide bone tissue regeneration in critical-sized calvarial defects with promising therapeutic efficacy.

Recent development in antimicrobial activity of biopolymer-inorganic nanoparticle composites with water disinfection potential: a comprehensive review

Nowadays, water-borne diseases including hepatitis remain the critical health challenge due to the inadequate supply of potable and safe water for human activities. The major cause is that the pathogenic microorganisms causing diseases have developed resistance against common techniques used by sewage water treatment plants for water disinfection. Therefore, there is a need to improve these conventional water treatment techniques by taking into consideration the application of nanotechnology for wastewater purification. The main aim of this paper is to provide a review on the synthesis of biopolymer-inorganic nanoparticle composites (BINCs), their used as antimicrobial compounds for water disinfection, as well as to elaborate on their antimicrobial mechanism of action. The microbial properties affecting the activity of antimicrobial compounds are also evaluated.

Reparative effect of super active platelet combined with allogeneic bone for large bone defects

In clinical practice, autologous bone transplantation is usually used to treat large-scale bone defects. However, autologous bone can cause complications such as secondary injury to patients, the scarcity of autografts. In this study, the study of using super active platelet lysate (sPL) and allogeneic bone to treat the 15 mm long bone defect in right radius of rabbits, and provide an experimental basis for the next step of clinical bone defect treatment. The critical-size defect of New Zealand white rabbits was made and divided into three groups: autologous bone group, allogeneic bone group, and sPL group. They were euthanized 1, 2, and 3 months after the operation, perform imaging and histological observation on the repair of bone defect area. The results showed that there were varying degrees of new bone in the bone defect. CT data showed that the bone defect repair rate and new bone mass in each group increased month by month (P <.05). Bone tissue (BV) and bone tissue to the total volume (BV/TV, %) in the sPL group > allogeneic bone group, autologous bone group > allogeneic bone group, with statistical significance (P < .05). Compared with the allogeneic bone group, the sPL group can significantly promote the healing of bone defects, enhance the bone density after fracture healing. The repair effect after 3 months was similar to that of the autogenous bone group. The use of allogeneic bone and sPL therapy may become part of a comprehensive strategy for tissue engineering to treat bone defects.

A flexible fibrous membrane based on copper(II) metal-organic framework/poly(lactic acid) composites with superior antibacterial performance

A flexible antibacterial fibrous membrane employing high antibacterial efficiency has great potential in healthcare applications. Herein, a three-dimensional copper(ii) metal-organic framework [Cu2(CA)(H2O)2, Cu-MOF-1] and poly(lactic acid) (PLA) composite fibrous membrane was prepared through a facile electrospinning method. The sphere-like Cu-MOF-1 was rapidly synthesized by a microwave-assisted hydrothermal reaction of Cu(ii) salts with citric acid (H4CA) in the presence of polyvinyl pyrrolidone (PVP). The surface morphology, thermal stability, mechanical properties and hydrophilicity test of the as-prepared Cu-MOF-1/PLA fibrous membrane were studied systematically. Compared with commercial copper nanoparticles (Cu-NPs), citric acid and copper citrate, Cu-MOF-1 showed higher antibacterial properties with the bacteriostatic rates of 97.9% and 99.3% against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively, when the used dose was 250 μg mL-1. The Cu-MOF-1/PLA fibrous membrane also exhibited outstanding bactericidal activities against E. coli and S. aureus with the antibacterial rates up to 99.3% and 99.8%, respectively. Mechanism investigation indicated that the slowly released Cu2+ ions could destroy the microenvironment of bacteria cells and destroy the integrity and permeability of the cell membrane, leading to enzyme inactivation. Therefore, the as-prepared flexible fibrous membrane will advance progress toward developing a broad spectrum antibacterial textile for healthcare protection related applications.

Copper-based biomaterials for bone and cartilage tissue engineering

Backgroud

Tissue engineering using cells, scaffolds, and bioactive molecules can promote the repair and regeneration of injured tissues. Copper is an essential element for the human body that is involved in many physiological activities and in recent years, copper has been used increasingly in tissue engineering.

Methods

The current advances of copper-based biomaterial for bone and cartilage tissue engineering were searched on PubMed and Web of Science.

Results

Various forms of copper-based biomaterials, including pure copper, copper ions, copper nanoparticles, copper oxides, and copper alloy are introduced. The incorporation of copper into base materials provides unique properties, resulting in tuneable porosity, mechanical strength, degradation, and crosslinking of scaffolds. Copper also shows promising biological performance in cell migration, cell adhesion, osteogenesis, chondrogenesis, angiogenesis, and antibacterial activities. In vivo applications of copper for bone and cartilage tissue engineering are discussed.

Conclusion

This review focuses on copper’s physiochemical and biological effects, and its applications in bone and cartilage tissue engineering. The potential limitations and future perspectives are also discussed.

Translational potential of this article

This review introduces the recent advances in copper-based biomaterial for bone and cartilage tissue engineering. This revie could guide researchers to apply copper in biomaterials, improving the generation of bone and cartilages, decrease the possibility of infection and shorten the recovery time so as to decrease medical costs.

Cotransplantation of mesenchymal stem cells and endothelial progenitor cells for treating steroid-induced osteonecrosis of the femoral head

Steroid-induced osteonecrosis of the femoral head (ONFH) is characterized by decreased osteogenesis, angiogenesis, and increased adipogenesis. While bone tissue engineering has been widely investigated to treat ONFH, its therapeutic effects remain unsatisfactory. Therefore, further studies are required to determine optimal osteogenesis, angiogenesis and adipogenesis in the necrotic area of the femoral head. In our study, we developed a carboxymethyl chitosan/alginate/bone marrow mesenchymal stem cell/endothelial progenitor cell (CMC/ALG/BMSC/EPC) composite implant, and evaluated its ability to repair steroid-induced ONFH. Our in vitro studies showed that BMSC and EPC coculture displayed enhanced osteogenic and angiogenic differentiation. When compared with single BMSC cultures, adipogenic differentiation in coculture systems was reduced. We also fabricated a three-dimensional (3D) CMC/ALG scaffold for loading cells, using a lyophilization approach, and confirmed its good cell compatibility characteristics, that is, high porosity, low cytotoxicity and favorable cell adhesion. 3D coculture of BMSCs and EPCs also promoted secretion of osteogenic and angiogenic factors. Then, we established an rabbit model of steroid-induced ONFH. The CMC/ALG/BMSC/EPC composite implant was transplanted into the bone tunnel of the rabbit femoral head after core decompression (CD) surgery. Twelve weeks later, radiographical and histological analyses revealed CMC/ALG/BMSC/EPC composite implants had facilitated the repair of steroid-induced ONFH, by promoting osteogenesis and angiogenesis, and reducing adipogenesis when compared with CD, CMC/ALG, CMC/ALG/BMSC and CMC/ALG/EPC groups. Thus, our data show that cotransplantation of BMSCs and EPCs in 3D scaffolds is beneficial in treating steroid-induced ONFH.

Bio-functional strontium-containing photocrosslinked alginate hydrogels for promoting the osteogenic behaviors

In recent years, photocrosslinked alginate hydrogel has been widely studied in bone tissue engineering, owing to its numerous advantages. However, there are still some shortcomings like insufficient mechanical strength and lack of bone induction. To compensate for these deficiencies, in this work, a novel doped strontium (Sr) photocrosslinked methacrylated alginate (Sr-PMA) hydrogel was developed. Photocrosslinked alginate hydrogel fabricated via crosslinking methacrylate-modified alginate under ultraviolet (UV) light was placed into strontium solutions to prepare Sr-PMA gel by chelating reaction. The chemical structures, swelling behaviors, degradation profiles, elastic moduli, Sr²⁺ ion release and surface morphology of the Sr-PMA hydrogel were characterized, and we found that physical properties of the gels can be tailored by varying concentration of Sr²⁺ ions. And MC3T3-E1 cell viability, proliferation and mineralization outside the hydrogel were also investigated. Further research on cell survival, multiplication, osteogenic differentiation of the cells encapsulated in Sr-PMA hydrogels were explored. In vitro studies of biological properties revealed that incorporation of Sr²⁺ into photocrosslinked alginate gels significantly improved osteogenic differentiation capabilities and mineralization via stimulating expression of osteogenesis related genes and proteins of the cells compared to strontium-free photocrosslinked alginate gels. The research demonstrates that the innovative Sr-PMA hydrogels possessing adjustable physical performances, excellent biocompatibility and osteogenic differentiation capabilities could be potentially applied to bone tissue engineering and regenerative medicine. Meanwhile, it also provides a reference for the modification of biological properties of biomaterials.

Biological Roles and Delivery Strategies for Ions to Promote Osteogenic Induction

Bone is the most studied tissue in the field of tissue regeneration. Even though it has intrinsic capability to regenerate upon injury, several pathologies and injuries could hamper the highly orchestrated bone formation and resorption process. Bone tissue engineering seeks to mimic the extracellular matrix of the tissue and the different biochemical pathways that lead to successful regeneration. For many years, the use of extrinsic factors (i.e., growth factors and drugs) to modulate these biological processes have been the preferred choice in the field. Even though it has been successful in some instances, this approach presents several drawbacks, such as safety-concerns, short release profile and half-time life of the compounds. On the other hand, the use of inorganic ions has attracted significant attention due to their therapeutic effects, stability and lower biological risks. Biomaterials play a key role in such strategies where they serve as a substrate for the incorporation and release of the ions. In this review, the methodologies used to incorporate ions in biomaterials is presented, highlighting the osteogenic properties of such ions and the roles of biomaterials in controlling their release.

Copper-containing bioactive glasses and glass-ceramics: From tissue regeneration to cancer therapeutic strategies

Copper is one of the most used therapeutic metallic elements in biomedicine, ranging from antibacterial approaches to cancer theranostics. This element could be easily incorporated into different types of biomaterials; specifically, copper-doped bioactive glasses (BGs) provide great opportunities for biomedical engineers and clinicians as regards their excellent biocompatibility and regenerative potential. Although copper-incorporated BGs are mostly used in bone tissue engineering, accelerated soft tissue healing is achievable, too, with interesting potentials in wound treatment and skin repair. Copper can modulate the physico-chemical properties of BGs (e.g., reactivity with bio-fluids) and improve their therapeutic potential. Improving cell proliferation, promoting angiogenesis, reducing or even prohibiting bacterial growth are counted as prominent biological features of copper-doped BGs. Recent studies have also suggested the suitability of copper-doped BGs in cancer photothermal therapy (PTT). However, more research is needed to determine the extent to which copper-doped BGs are actually applicable for tissue engineering and regenerative medicine strategies in the clinic. Moreover, copper-doped BGs in combination with polymers may be considered in the future to produce relatively soft, pliable composites and printable inks for use in biofabrication.

[Research progress on antibacterial properties of porous medical implant materials]

OBJECTIVE

The antibacterial properties of porous medical implant materials were reviewed to provide guidance for further improvement of new medical implant materials.

METHODS

The literature related to the antibacterial properties of porous medical implant materials in recent years was consulted, and the classification, characteristics and applications, and antibacterial methods of porous medical implant materials were reviewed.

RESULTS

Porous medical implant materials can be classified according to surface pore size, preparation process, degree of degradation in vivo, and material source. It is widely used in the medical field due to its good biocompatibility and biomechanical properties. Nevertheless, the antibacterial properties of porous medical implant materials themselves are not obvious, and their antibacterial properties need to be improved through structural modification, overall modification, and coating modification.

CONCLUSION

At present, coating modification as the mainstream modification method for improving the antibacterial properties of porous medical materials is still a research hotspot. The introduction of new antibacterial substances provides a new perspective for the development of new coated porous medical implant materials, so that the porous medical implant materials have a more reliable antibacterial effect while taking into account biocompatibility.

Chelation Crosslinking of Biodegradable Elastomers

Widely present in nature and in manufactured goods, elastomers are network polymers typically crosslinked by strong covalent bonds. Elastomers crosslinked by weak bonds usually exhibit more plastic deformation. Here, chelation as a mechanism to produce biodegradable elastomers is reported. Polycondensation of sebacic acid, 1,3-propanediol, and a Schiff-base (2-[[(2-hydroxyphenyl) methylene]amino]-1,3-propanediol) forms a block copolymer that binds several biologically relevant metal ions. Chelation offers a unique advantage unseen in conventional elastomer design because one ligand binds multiple metal ions, yielding bonds of different strengths. Therefore, one polymeric ligand coordinated with different metal ions produces elastomers with vastly different characteristics. Mixing different metal ions in one polymer offers another degree of control on material properties. The density of the ligands in the block copolymer further regulates the mechanical properties. Moreover, a murine model reveals that Fe³⁺ crosslinked foam displays higher compatibility with subcutaneous tissues than the widely used biomaterial-polycaprolactone. The implantation sites restore to their normal architecture with little fibrosis upon degradation of the implants. The versatility of chelation-based design has already shown promise in hydrogels and highly stretchy nondegradable polymers. The biodegradable elastomers reported here would enable new materials and new possibilities in biomedicine and beyond.

Calcium silicate bioactive ceramics induce osteogenesis through oncostatin M

Immune reactions are a key factor in determining the destiny of bone substitute materials after implantation. Macrophages, the most vital factor in the immune response affecting implants, are critical in bone formation, as well as bone biomaterial-mediated bone repair. Therefore, it is critical to design materials with osteoimmunomodulatory properties to reduce host-to-material inflammatory responses by inducing macrophage polarization. Our previous study showed that calcium silicate (CS) bioceramics could significantly promote osteogenesis. Herein, we further investigated the effects of CS on the behavior of macrophages and how macrophages regulated osteogenesis. Under CS extract stimulation, the macrophage phenotype was converted to the M2 extreme. Stimulation by a macrophage-conditioned medium that was pretreated by CS extracts resulted in a significant enhancement of osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), indicating the important role of macrophage polarization in biomaterial-induced osteogenesis. Mechanistically, oncostatin M (OSM) in the macrophage-conditioned medium promoted osteogenic differentiation of BMSCs through the ERK1/2 and JAK3 pathways. This in vivo study further demonstrated that CS bioceramics could stimulate osteogenesis better than β-TCP implants by accelerating new bone formation at defective sites in the femur. These findings improve our understanding of immune modulation of CS bioactive ceramics and facilitate strategies to improve the in vitro osteogenesis capability of bone substitute materials.

•

Calcium silicate (CS) bioceramics significantly promoted osteogenesis by the regulating of macrophage polarization.

•

ERK1/2 and JAK3 pathways mediated the osteogenic differentiation stimulated by CS.

•

CS played a promising osteoimmunomodulatory agent for bone induction.

Chitosan-based drug delivery systems: From synthesis strategy to osteomyelitis treatment - A review

Osteomyelitis is a complex disease in orthopedics mainly caused by bacterial pathogens invading bone or bone marrow. The treatment of osteomyelitis is highly difficult and it is a major challenge in orthopedic surgery. The long-term systemic use of antibiotics may lead to antibiotic resistance and has limited effects on eradicating local biofilms. Localized antibiotic delivery after surgical debridement can overcome the problem of antibiotic resistance and reduce systemic toxicity. Chitosan, a special cationic polysaccharide, is a product extracted from the deacetylation of chitin. It has numerous advantages, such as nontoxicity, biocompatibility, and biodegradability. Recently, chitosan has attracted significant attention in bacterial inhibition and drug delivery. Because chitosan contains many functional bioactive groups conducive to chemical reaction and modification, some chitosan-based biomaterials have been applied as the local antibiotic delivery systems in the treatment of osteomyelitis. This review aims to introduce recent advances in the biomedical applications of chitosan-based drug delivery systems in osteomyelitis treatment and to highlight the perspectives for further studies.

Superior antibacterial activity of Fe3O4@copper(ii) metal-organic framework core-shell magnetic microspheres

With the rapid evolution of antibiotic resistant bacteria, it has become more and more difficult to treat bacterial infection with traditional antibiotics. Therefore, new strategies with high antibacterial efficiency are urgently needed to combat bacteria effectively. Herein, Fe₃O₄@copper(ii) metal-organic framework Cu₃(BTC)₂ (Cu-BTC) core-shell structured magnetic microspheres were prepared via a layer by layer growth process. The as-prepared Fe₃O₄@Cu-BTC possessed a unique broad-spectrum antibacterial potency against Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus). The slowly released copper ions and enhanced reactive oxygen species (ROS) generation by facilitating the effective separation and transfer of photoexcited electron-hole pairs played a role in the antibacterial activity of Fe₃O₄@Cu-BTC. Copper ions released from Fe₃O₄@Cu-BTC adhered to the negatively charged bacterial cell, interacted with the bacterial membrane, destroyed the integrity of the membrane which resulted in leakage of bacterial content and then generated ROS to damage DNA, thus leading to cell death. Accordingly, this study provides a competitive strategy for preparing recyclable antibacterial materials that are endowed with targeted antibacterial therapy.

Injectable biodegradation-visual self-healing citrate hydrogel with high tissue penetration for microenvironment-responsive degradation and local tumor therapy

Local tumor therapy through injectable biodegradable hydrogels with controlled drug release has attracted much attention recently, due to their easy operation, low side effect and efficiency. However, most of the reported therapeutic hydrogel system showed a lack of biodegradation tracking and tumor environment-responsive degradation/therapy. Herein, we developed a multifunctional injectable biodegradation-visual citric acid-based self-healing scaffolds with microenvironment-responsive degradation and drug release for safe and efficient skin tumor therapy (FPRC hydrogel). FPRC scaffolds possess multifunctional properties including thermosensitive, injectable, self-healing, photoluminescent and pH-responsive degradation/drug release. The FPRC scaffolds with strong red fluorescence which has good photostability, tissue penetration and biocompatibility can be tracked and monitored to evaluate the degradation of the scaffolds in vivo. Moreover, the FPRC scaffolds showed pH-responsive doxorubicin (DOX) release, efficiently killed the A375 cancer cell in vitro and suppressed the tumor growth in vivo. Compared to the free drug (DOX), the FPRC@DOX scaffolds displayed a significantly high therapeutic effect and less biotoxicity. This work provides an alternative strategy to design smart visual scaffolds for tumor therapy and regenerative medicine.

Energy Conversion-Based Nanotherapy for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is characterized by synovial hyperplasia and cartilage/bone destruction, which results in a high disability rate on human health and a huge burden on social economy. At present, traditional therapies based on drug therapy still cannot cure RA, in accompany with the potential serious side effects. Based on the development of nanobiotechnology and nanomedicine, energy conversion-based nanotherapy has demonstrated distinctive potential and performance in RA treatment. This strategy employs specific nanoparticles with intrinsic physiochemical properties to target lesions with the following activation by diverse external stimuli, such as light, ultrasound, microwave, and radiation. These nanoagents subsequently produce therapeutic effects or release therapeutic factors to promote necrotic apoptosis of RA inflammatory cells, reduce the concentration of related inflammatory factors, relieve the symptoms of RA, which are expected to ultimately improve the life quality of RA patients. This review highlights and discusses the versatile biomedical applications of energy conversion-based nanotherapy in efficient RA treatment, in together with the deep clarification of the facing challenges and further prospects on the final clinical translations of these energy conversion-based nanotherapies against RA.

Biomaterials against Bone Infection

Chronic bone infection is considered as one of the most problematic biofilm-related infections. Its recurrent and resistant nature, high morbidity, prolonged hospitalization, and costly medical care expenses have driven the efforts of the scientific community to develop new therapies to improve the standards used today. There is great debate on the management of this kind of infection in order to establish consistent and agreed guidelines in national health systems. The scientific research is oriented toward the design of anti-infective biomaterials both for prevention and cure. The properties of these materials must be adapted to achieve better anti-infective performance and good compatibility, which allow a good integration of the implant with the surrounding tissue. The objective of this review is to study in-depth the antibacterial biomaterials and the strategies underlying them. In this sense, this manuscript focuses on antimicrobial coatings, including the new technological advances on surface modification; scaffolding design including multifunctional scaffolds with both antimicrobial and bone regeneration properties; and nanocarriers based on mesoporous silica nanoparticles with advanced properties (targeting and stimuli-response capabilities).

Drug-free and non-crosslinked chitosan scaffolds with efficient antibacterial activity against both Gram-negative and Gram-positive bacteria

Treatment of oral pathogens is important for both oral and systemic health. The antimicrobial activity of chitosan (CS)-based scaffolds either loading antibiotics or compositing with other agents are well documented. However, the intrinsic antibacterial activity of CS scaffolds alone has never been reported. Herein, we fabricated the non-crosslinked CS scaffold and investigated its antibacterial activity against typical oral pathogens, Gram-negative Porphyromonas gingivalis and Gram-positive Streptococcus mutans. We found both pathogens were completely killed by 1 mg CS scaffolds at 6 h, due largely to the CS-induced time-dependent bacteria clustering. Interestingly, β-glycerophosphate crosslinked scaffolds showed no antibacterial activity. In conclusion, the bactericidal activity of CS scaffolds alone is reported for the first time. Together with the biodegradability, physical stability, biocompatibility and great antibacterial activity, the non-crosslinked CS scaffolds may have great potentials not only in treating oral diseases but also in wound healing and tissue engineering.

Fabrication and characterization of Spinacia oleracea extract incorporated alginate/carboxymethyl cellulose microporous scaffold for bone tissue engineering

In recent years, plant based scaffold due to its inherent properties such as mechanical stability, renewability, easy mass production, inexpensiveness, biocompatibility and biodegradability with low toxic effects have received much attention in the field of bone tissue engineering. Design of good tissue compatible plant based polymer scaffold plays a vital role in biomedicine, nanomedicine and in various tissue engineering applications. The present study focused on the fabrication of a novel herbal scaffold using the medicinal plants Spinacia oleracea (SO) and Cissus quadrangularis (CQ) extracts incorporated with Alginate (Alg), Carboxy Methyl Cellulose (CMC) by lyophilization method. The structural nature and the properties of prepared scaffold were analyzed by XRD, FE-SEM, FTIR, EDAX, TGA, swelling ratio, porosity, in-vitro degradation and cell viability studies. The biocompatible nature of the plant based polymer scaffold was assessed using MG-63 Human Osteosarcoma cell line. The investigation of biocompatibility study showed that Alg/CMC/SO scaffold expressed higher cell viability than Alg/CMC/SO-CQ scaffold, which possess better cellular biocompatibility. The results of the present study suggested that plant based Alg/CMC/SO scaffold serve as a potential biopolymer scaffold which could be further exploited for bone tissue applications.

Hyaluronic acid/corn silk extract based injectable nanocomposite: A biomimetic antibacterial scaffold for bone tissue regeneration

Injectable hydrogels have revealed the great potential for use as scaffolds in cartilage and bone tissue engineering. Here, thermosensitive and injectable hydrogels containing β-tricalcium phosphate, hyaluronic acid, and corn silk extract-nanosilver (CSE-Ag NPs) were synthesized for their potential use in bone tissue regeneration applications. Spherical nanoparticles of silver were biosynthesized through microwave-assisted green approach using CSE in organic solvent-free medium. Rheological experiments demonstrated that the thermosensitive hydrogels have gelification temperature (T_gel) close to body temperature. The samples containing Ag NPs showed antibacterial activity toward gram-positive (Bacillus Subtilis, Staphylococcus Aureus) and gram-negative (Pseudomonas Aeruginosa, Escherichia Coli) bacteria along without cytotoxicity after 24 h. Mesenchymal stem cells seeded in the nanocomposite exhibited high bone differentiation which indicate that thay could be a good candidate as a potential scaffold for bone tissue regeneration.

Intelligent Metal-Phenolic Metallogels as Dressings for Infected Wounds

In this study, we report a metallogel developed based on metal-phenolic coordination of natural low-cost polyphenolic molecule and metal ions. Gelation occurs by mixing tannic acid (TA) and group (IV) titanium ions (Ti^IV) to form TA-Ti^IV gel. The TA-Ti^IV gel exhibits good capability to incorporate diverse metal ions by in situ co-gelation. Herein, five antimicrobial metal ions, i.e. ferric (Fe^III), copper (Cu^II), zinc (Zn^II), cobalt (Co^II) and nickel (Ni^II) ions, were employed to include in TA-Ti^IV gels for developing intelligent dressings for infected wounds. The chemical and coordinative structures of TA-Ti^IV metallogels were characterized by UV-Vis and Fourier-transform infrared (FT-IR) spectroscopies. Cytotoxicity of antimicrobial metallogels was explored by MTT assay with NIH 3T3 fibroblasts. The release of metal ions was evaluated by inductively coupled plasma mass spectrometry (ICP-MS), indicating the different releasing profiles upon the coordinative interactions of metal ions with TA. The formation and disassembly of metallogels are sensitive to the presence of acid and an oxidizer, H₂O₂, which are substances spontaneously generated in infected wounds due to the metabolic activity of bacteria and the intrinsic immune response. The Cu^II releasing rates of TA-Ti^IV-Cu^II metallogels at different pH values of 5.5, 7.4 and 8.5 have been studied. In addition, addition of H₂O₂ trigger fast release of Cu^II as a result of oxidation of galloyl groups in TA. Consequently, the antimicrobial potency of TA-Ti^IV-Cu^II metallogels can be simultaneously activated while the wounds are infected and healing. The antimicrobial property of metallogels against Gram-negative Escherichia coli, and Gram-positive Methicillin-Resistant Staphylococcus aureus (USA300) and Staphylococcus epidermidis has been investigated by agar diffusion test. In an animal model, the TA-Ti^IV-Cu^II metallogels were applied as dressings for infected wounds, indicating faster recovery in the wound area and extremely lower amount of bacteria around the wounds, compared to TA-Ti^IV gels and gauze. Accordingly, the intelligent nature derived metallogels is a promising and potential materials for medical applications.