Electrophoretic deposition of collagen/chitosan films with copper-doped phosphate glasses for orthopaedic implants

Highly Efficient Electrophoretic Deposition of Durable, Corrosion-Resistant Chitosan-PEG Composites on Metallic Implants

In this work, the electrophoretic deposition (EPD) of uniform and mechanically stable chitosan/poly(ethylene glycol) (PEG) films from a biphase H2O/CO2 medium under high pressure was proposed. This solvent has a pronounced sterilizing ability and spontaneously self-neutralizes during decompression, becoming a fully biocompatible medium. In such a medium, chitosan aggregates much less than in traditional acid solutions, which allows greater electrophoretic mobility of the macromolecules during EPD of the coating and contributes to an increase in the efficiency of the coating application. The addition of PEG improves the insufficient mechanical strength of the chitosan films, increasing their hardness and adhesion to the substrate. The average peel strengths were 0.15 ± 0.09 N mm-1 for the chitosan coating and 0.7 ± 0.2 N mm-1 for the chitosan/PEG composite. The interaction of chitosan and PEG, which form intermolecular complexes due to hydrogen bonding, was studied by Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, and X-ray photoelectron spectroscopy methods. The contact angles of water droplets on the obtained coatings are in the optimal range for bone cell proliferation: 35-85°. High biocompatibility of the coatings was confirmed by evaluating the cytotoxicity using the methyl-thiazol tetrazolium assay with C2C12 osteo-like cells. The coatings show good corrosion resistance due to their high adhesion to metal. Composite coating demonstrated a shift in the corrosion potential toward positive values by 0.1 V, and a drop in corrosion current density by an order of magnitude as compared to the bare titanium substrate. The morphology of the coatings was evaluated by atomic force microscopy, scanning electron microscopy, and profilometry methods, and it was shown that the addition of PEG leads to a significant decrease in the coating thickness (2 μm), while increasing the uniformity. The roughness of the coatings is in the submicron range.

Electrophoretic Deposition of Chitosan Coatings on the Porous Titanium Substrate

Medicine is looking for solutions to help implant patients recover more smoothly. The porous implants promote osteointegration, thereby providing better stabilization. Introducing porosity into metallic implants enhances their biocompatibility and facilitates osteointegration. The introduction of porosity is also associated with a reduction in Young's modulus, which reduces the risk of tissue outgrowth around the implant. However, the risk of chronic inflammation remains a concern, necessitating the development of coatings to mitigate adverse reactions. An interesting biomaterial for such modifications is chitosan, which has antimicrobial, antifungal, and osteointegration properties. In the present work, a porous titanium biomaterial was obtained by powder metallurgy, and electrophoretic deposition of chitosan coatings was used to modify its surface. This study investigated the influence of ethanol content in the deposition solution on the quality of chitosan coatings. The EPD process facilitates the control of coating thickness and morphology, with higher voltages resulting in thicker coatings and increased pore formation. Ethanol concentration in the solution affects coating quality, with higher concentrations leading to cracking and peeling. Optimal coating conditions (30 min/10 V) yield high-quality coatings, demonstrating excellent cell viability and negligible cytotoxicity. The GIXD and ATR-FTIR analysis confirmed the presence of deposited chitosan coatings on Ti substrates. The microstructure of the chitosan coatings was examined by scanning electron microscopy. Biological tests showed no cytotoxicity of the obtained materials, which allows for further research and the possibility of their use in medicine. In conclusion, EPD offers a viable method for producing chitosan-based coatings with controlled properties for biomedical applications, ensuring enhanced patient outcomes and implant performance.

Construction of Magnesium Phosphate Chemical Conversion Coatings with Different Microstructures on Titanium to Enhance Osteogenesis and Angiogenesis

Titanium (Ti) and its alloys are widely used as hard tissue substitutes in dentistry and orthopedics, but their low bioactivity leads to undesirable osseointegration defects in the early osteogenic phase. Surface modification is an important approach to overcome these problems. In the present study, novel magnesium phosphate (MgP) coatings with controllable structures were fabricated on the surface of Ti using the phosphate chemical conversion (PCC) method. The effects of the microstructure on the physicochemical and biological properties of the coatings on Ti were researched. The results indicated that accelerators in PCC solution were important factors affecting the microstructure and properties of the MgP coatings. In addition, the coated Ti exhibited excellent hydrophilicity, high bonding strength, and good corrosion resistance. Moreover, the biological results showed that the MgP coatings could improve the spread, proliferation, and osteogenic differentiation of mouse osteoblast cells (MC3T3-E1) and vascular differentiation of human umbilical vein endothelial cells (HUVECs), indicating that the coated Ti samples had a great effect on promoting osteogenesis and angiogenesis. Overall, this study provided a new research idea for the surface modification of conventional Ti to enhance osteogenesis and angiogenesis in different bone types for potential biomedical applications.

AgBiS2@CQDs/Ti nanocomposite coatings for combating implant-associated infections by photodynamic /photothermal therapy

Biofilm-mediated implant-associated infections are one of the most serious complications of implantation surgery, posing a grave threat to patient well-being. Effectively addressing bacterial infections is crucial for the success of implantation procedures. In this study, we prepared a bismuth sulfide silver@carbon quantum dot composite coating (AgBiS2@CQDs/Ti) on a medical titanium surface by surface engineering design to treat implant-associated infections. The photocatalytic/photothermal activity test results confirmed the excellent photogenerated ROS and photothermal properties of AgBiS2@CQDs/Ti under near-infrared laser irradiation. In vitro antibacterial and in vivo anti-infection experiments showed that the coating combined with photodynamic and photothermal therapies to eradicate bacteria and disrupt mature biofilms under 1064 nm laser irradiation. Consequently, AgBiS2@CQDs/Ti shows promise as an implant coating for treating implant-associated infections post-surgery, thereby enhancing the success rate of implantation procedures. This study also provides a new idea for combating implant-associated infections.

Advances of Blood Coagulation Factor XIII in Bone Healing

The biologic process of bone healing is complicated, involving a variety of cells, cytokines, and growth factors. As a result of bone damage, the activation of a clotting cascade leads to hematoma with a high osteogenic potential in the initial stages of healing. A major factor involved in this course of events is clotting factor XIII (FXIII), which can regulate bone defect repair in different ways during various stages of healing. Autografts and allografts often have defects in clinical practice, making the development of advanced materials that support bone regeneration a critical requirement. Few studies, however, have examined the promotion of bone healing by FXIII in combination with biomaterials, in particular, its effect on blood coagulation and osteogenesis. Therefore, we mainly summarized the role of FXIII in promoting bone regeneration by regulating the extracellular matrix and type I collagen, bone-related cells, angiogenesis, and platelets, and described the research progress of FXIII = related biomaterials on osteogenesis. This review provides a reference for investigators to explore the mechanism by which FXIII promotes bone healing and the combination of FXIII with biomaterials to achieve targeted bone tissue repair.

Critical Review on the Developments in Polymer Composite Materials for Biomedical Implants

There has been a lack of research for developing functional polymer composites for biomedical implants. Even though metals are widely used as implant materials, there is a need for developing polymer composites as implant materials because of the stress shielding effect that causes a lack of compatibility of metals with the human body. This review aims to bring out the latest developments in polymer composite materials for body implants and to emphasize the significance of polymer composites as a viable alternative to conventional materials used in the biomedical industry for ease of life. This review article explores the developments in functional polymer composites for biomedical applications and provides distinct divisions for their applications based on the part of the body where they are implanted. Each application has been covered in some detail. The various applications covered are bone transplants and bone regeneration, cardiovascular implants (stents), dental implants and restorative materials, neurological and spinal implants, and tendon and ligament replacement.

Antimicrobial coating strategy to prevent orthopaedic device-related infections: recent advances and future perspectives

The rapid development of multidrug-resistant (MDR) bacteria and biofilm-related infections (BRIs) has urgently called for new strategies to combat severe orthopaedic device-related infections (ODRIs). Antimicrobial coating has emerged as a promising strategy in halting the incidence of ODRIs and treating ODRIs in long term. With the advancement of material science and biotechnology, numerous antimicrobial coatings have been reported in literature, showing superior antimicrobial and osteogenic functions. This review has specifically discussed the currently developed antimicrobial coatings in the perspective of drug release from the coating system, focusing on their realization of controlled and on demand antimicrobial agents release, as well as multi-functionality. Acknowledging the multidisciplinary nature of antimicrobial coating, the conceptual design, the deposition method and the therapeutic effect of the antimicrobial coatings have been described in detail and discussed critically. Particularly, the challenges and opportunities on the way toward the clinical translation of antimicrobial coatings have been highlighted.

Advancements in Fabrication and Application of Chitosan Composites in Implants and Dentistry: A Review

Chitosan is a biopolymer that is found in nature and is produced from chitin deacetylation. Chitosan has been studied thoroughly for multiple applications with an interdisciplinary approach. Antifungal antibacterial activities, mucoadhesion, non-toxicity, biodegradability, and biocompatibility are some of the unique characteristics of chitosan-based biomaterials. Moreover, chitosan is the only widely-used natural polysaccharide, and it is possible to chemically modify it for different applications and functions. In various fields, chitosan composite and compound manufacturing has acquired much interest in developing several promising products. Chitosan and its derivatives have gained attention universally in biomedical and pharmaceutical industries as a result of their desired characteristics. In the present mini-review, novel methods for preparing chitosan-containing materials for dental and implant engineering applications along with challenges and future perspectives are discussed.