Accelerated fabrication of antibacterial and osteoinductive electrospun fibrous scaffolds via electrochemical deposition

Scaffolds in the microbial resistant era: Fabrication, materials, properties and tissue engineering applications

Due to microbial infections dramatically affect cell survival and increase the risk of implant failure, scaffolds produced with antimicrobial materials are now much more likely to be successful. Multidrug-resistant infections without suitable prevention strategies are increasing at an alarming rate. The ability of cells to organize, develop, differentiate, produce a functioning extracellular matrix (ECM) and create new functional tissue can all be controlled by careful control of the extracellular microenvironment. This review covers the present state of advanced strategies to develop scaffolds with antimicrobial properties for bone, oral tissue, skin, muscle, nerve, trachea, cardiac and other tissue engineering applications. The review focuses on the development of antimicrobial scaffolds against bacteria and fungi using a wide range of materials, including polymers, biopolymers, glass, ceramics and antimicrobials agents such as antibiotics, antiseptics, antimicrobial polymers, peptides, metals, carbon nanomaterials, combinatorial strategies, and includes discussions on the antimicrobial mechanisms involved in these antimicrobial approaches. The toxicological aspects of these advanced scaffolds are also analyzed to ensure future technological transfer to clinics. The main antimicrobial methods of characterizing scaffolds’ antimicrobial and antibiofilm properties are described. The production methods of these porous supports, such as electrospinning, phase separation, gas foaming, the porogen method, polymerization in solution, fiber mesh coating, self-assembly, membrane lamination, freeze drying, 3D printing and bioprinting, among others, are also included in this article. These important advances in antimicrobial materials-based scaffolds for regenerative medicine offer many new promising avenues to the material design and tissue-engineering communities.

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Antibacterial, antifungal and antibiofilm scaffolds.

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Antimicrobial scaffold fabrication techniques.

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Antimicrobial biomaterials for tissue engineering applications.

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Antimicrobial characterization methods of scaffolds.

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Bone, oral tissue, skin, muscle, nerve, trachea, cardiac, among other applications.

Bi-layered nanofibrous membrane with osteogenic and antibacterial functions for periodontal tissue regeneration

Guided tissue regeneration (GTR) membranes have great potential to promote periodontal tissue regeneration and reestablishment. However, the regeneration potential and microbial infection resistance of current GTR membranes still need to be improved. Here, a bi-layered nanofibrous membrane on the basis of poly (lactic-co-glycolic acid) (PLGA)/gelatin with osteogenic and antibacterial functions was fabricated for periodontal tissue regeneration. The antimicrobial layer (AL) of the bi-layered nanofibrous membrane was composed of nanofibrous PLGA/gelatin nanofibers loaded with nano-silver (nAg), while the osteoconductive layer (OL) of the nanofibrous membrane consisted of PLGA/gelatin nanofibers loaded with nano-hydroxyapatite (nHA). The bi-layered nanofibrous membrane was examined by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectrometry (XPS) and X-ray diffractometry (XRD). The results showed that nHA and nAg particles were well evenly loaded or embedded in PLGA/gelatin nanofibers. The cell culture experiments suggested that the bi-layered nanofibrous membrane possessed good cytocompatibility and the OL of the bi-layered nanofibrous membrane possessed an enhanced osteogenic capacity for human osteoblast-like cells (MG63), which was verified by the good cell viability and the increased alkaline phosphatase (ALP) activity, respectively. The results of in vitro antimicrobial study displayed that the AL of the bi-layered nanofibrous membrane possessed an effective antibacterial capability. In conclusion, the prepared bi-layered nanofibrous membrane with osteogenic and antibacterial functions may have great potential for periodontal tissue regeneration and reestablishment.[Formula: see text].

Drug-Eluting Medical Textiles: From Fiber Production and Textile Fabrication to Drug Loading and Delivery

Drug-eluting medical textiles have recently gained great attention to be used in different applications due to their cost effectiveness and unique physical and chemical properties. Using various fiber production and textile fabrication technologies, fibrous constructs with the required properties for the target drug delivery systems can be designed and fabricated. This review summarizes the current advances in the fabrication of drug-eluting medical textiles. Different fiber production methods such as melt-, wet-, and electro-spinning, and textile fabrication techniques such as knitting and weaving are explained. Moreover, various loading processes of bioactive agents to obtain drug-loaded fibrous structures with required physicochemical and morphological properties, drug delivery mechanisms, and drug release kinetics are discussed. Finally, the current applications of drug-eluting fibrous systems in wound care, tissue engineering, and transdermal drug delivery are highlighted.

Biofunctionalization of Porous Ti Substrates Coated with Ag Nanoparticles for Potential Antibacterial Behavior

Ti prosthesis have shown better biological compatibility, mechanical performance, and resistance to corrosion in cases of bone replacements. Nevertheless, fully dense Ti in connection with bone-host tissues show stress-shielding phenomenon that, together with the development of frequent undesirable microbial infections, may lead to implant failures. To overcome these issues, the present study aimed at the development of a novel combination of a chemically functionalized porous Ti substrate with a potentially therapeutic AgNPs coating. Fully dense and porous Ti substrates (30 and 60 vol.%, 100–200 and 355–500 μm, as spacer particles) were studied. Ti surface was treated with acid or basic medium followed by silanization and deposition of AgNPs by “submerged” and “in situ” methods. In general, for similar porosity, mechanical resistance decreased as pore size increased. Acidic reagent and submerged methodology were the best combination for fully dense Ti substrates. Hence, they were also employed for porous Ti substrates. Depending on the porosity of the substrates, variations can be observed both in the size and degree of agglomeration of the deposited AgNPs, entailing differences in the antibacterial behavior of the samples.

Minocycline hydrochloride loaded mPEG-PCLA membranes: Preparation and in vitro evaluation for periodontitis therapy

This study was aimed at alleviating shortcomings in the treatment of periodontitis by preparation of a biopolymer membrane loaded with minocycline hydrochloride (MH) inserted into periodontal pockets to treat infections. Monomethoxy-poly (ethylene glycol)-poly (ε-caprolactone-co-L-lactide) (mPEG-PCLA) is a biocompatible and biodegradable amphiphilic block copolymer. It, therefore, has attracted considerable attention in drug delivery systems and periodontal treatment. We chose it as a membrane material for MH-drug loading. The MH-loaded membranes were prepared by the solvent casting technique with the content of 5, 8 and 10 wt.%, respectively. Fourier transform infrared spectra (FTIR) revealed no interaction between MH and polymer. The drug-loaded membrane surface morphology was investigated by scanning electron microscopy (SEM). In vitro release studies showed that the initial drug release exceeded 40% within 24 h, followed by a sustained release for up to 2 weeks, which would enable the therapeutic level to maintain over a longer time. The antibacterial activity studies in vitro demonstrated a positive effect on the periodontal pathogen. MH drug-loaded membranes have no adverse effect on the growth of periodontal ligament fibroblasts in the MTT test. The study suggests that mPEG-PCLA membranes containing MH are a potential antibacterial drug delivery system for local treatment of periodontitis.

Novel hydroxyapatite/graphene oxide/collagen bioactive composite coating on Ti16Nb alloys by electrodeposition

A novel implant coating material containing graphene oxide (GO) and collagen (COL), and hydroxyapatite (HA) was fabricated with the aid of tannic acid by electrodeposition. The surface of Ti16Nb alloy was subjected to anodic oxidation, and then HA-GO coating was applied to Ti16Nb surface by cathodic method. Then, COL was deposited on the surface of the HA-GO coating by the biomimetic method. HA, HA-GO, HA-GO-COL coatings on the surface of the Ti16Nb alloy have increased the corrosion resistance by the formation of a barrier layer on the surface. For HA-GO-COL coating, the highest corrosion resistance is obtained due to the compactness and homogeneity of the coating structure. The contact angle of the bare Ti16Nb is approximately 65°, while the contact angle of the coated samples is close to 0°. Herein, the increased surface wettability is important for cell adhesion. The surface roughness of the uncoated Ti16Nb alloy was between 1 and 3 μm, while the surface roughness of the coated surfaces was measured between 20 and 110 μm. The contact between the bone and the implant has been improved. Graphene oxide-containing coatings have improved the antibacterial properties compared to the GO-free coating using S. aureus. The hardness and elastic modulus of the coatings were measured by the nanoindentation test, and the addition of GO and collagen to the HA coating resulted in an increase in strength. The addition of GO to the HA coating reduced the viability of 3 T3 fibroblast cells, whereas the addition of collagen to HA-GO coat increased the cell adhesion and viability.

Nanostructured magnetic Mg2SiO4-CoFe2O4 composite scaffold with multiple capabilities for bone tissue regeneration

Multifunctional magnetic 3D scaffolds are recently of particular interest because of their applications in hyperthermia-based therapy and localized drug delivery beside of their basic properties to be applied in bone tissue regeneration. In the current study, a magnetic nanocomposite is designed and synthesized through a two-step synthesis strategy in which CoFe₂O₄ nanoparticles are prepared via sol-gel combustion method and then they are coated through sol-gel method with Mg₂SiO₄. The characterization relates to the nanocomposite shows that Mg₂SiO₄-CoFe₂O₄ is successfully synthesized and it has a core-shell structure. Then, 3D scaffolds are fabricated through polymer sponge technique from the nanocomposite. Physiochemical and biological properties of the scaffolds are assessed in vitro amongst which bioactivity, biodegradability, mechanical properties, hyperthermia capability, controlled release potential, antibacterial activity, cell compatibility and attachment can be mentioned. The results demonstrate that the scaffolds have high porous structure with interconnected porosity and desirable mechanical properties close to cancellous bone. The magnetic scaffold is biodegradable and bioactive and exhibits controlled release of rifampin as an antibiotic drug up to 96 h. Moreover, in the exposure of different magnetic fields it has potential to produce heat for different kinds of hyperthermia-based therapies. The antibacterial activity of drug-loaded scaffold is assessed against S. aureus bacteria. The results suggest that Mg₂SiO₄-CoFe₂O₄ nanocomposite scaffold with multiple capabilities has a great potential to be applied in the case of large bone defects which are caused by tumors to not only eradicate remained cancerous tissues, but also prevent infection after surgery and regenerate bone defect.

Bi-layered electrospun nanofibrous membrane with osteogenic and antibacterial properties for guided bone regeneration

Guided bone regeneration (GBR) membranes have the potential to prevent the invasion of epithelial and connective tissues as well as to maintain a stable space for facilitating the ingrowth of regenerative bone tissue. However, the bioactivity and regeneration potential of currently available membranes still need to be improved. In this study, a novel bi-layered membrane with both osteogenic and antibacterial functions was developed for GBR applications. The loose layer (LL) of the membrane was composed of conjugated electrospun poly (lactic-co-glycolic acid) (PLGA)/gelatin nanofibers incorporating dexamethasone-loaded mesoporous silica nanoparticles (DEX@MSNs), while the dense layer (DL) of the membrane consisted of traditionally electrospun PLGA nanofibers loaded with the broad-spectrum antibiotic doxycycline hyclate (DCH). Morphological results showed that the LL (DEX@MSNs/PLGA/Gel) membrane exhibited a porous and loosely packed structure, which was beneficial for cell adhesion and infiltration, while the DL (DCH/PLGA) membrane remained dense enough to act as a barrier. In vitro drug release tests indicated that both DEX and DCH followed a favorable sustained release profile. The cell viability evaluation suggested that the electrospun membranes possessed good cytocompatibility. Furthermore, in vitro osteogenesis analyses demonstrated that the DEX@MSNs/PLGA/Gel composite membrane possessed an enhanced osteoinductive capacity for rat bone marrow stem cells (BMSCs), which was verified by the increased alkaline phosphatase (ALP) activity, the enhanced calcium deposition, and the upregulated osteocalcin (OCN) expression. In vitro antimicrobial experiments revealed the effective antibacterial potency of the DCH/PLGA membrane. In conclusion, the prepared nanocarrier-incorporated bi-layered composite membrane with combined osteogenic and antibacterial properties may be a promising candidate for GBR application.