Biosensitive and antibacterial coatings on metallic material for medical applications

Abstract

Metallic materials are commonly used for load-bearing implants and as internal fixation devices. It is customary to use austenitic stainless steel, especially surgical grade type 316L SS as temporary and Ti alloys as permanent implants. However, long-term, poor bonding with bone, corrosion, and release of metal ions, such as chromium and nickel occur. These ions are powerful allergens and carcinogens and their uncontrolled leaching may be avoided by surface coatings. Therefore, bioactive glasses (BGs) became a vital biomedical material, which can form a biologically active phase of hydroxycarbonate apatite on their surface when in contact with physiological fluids. To reduce the high coefficient of friction and the brittle nature of BGs, polymers are normally incorporated to avoid the high-temperature sintering/densification of ceramic-only coatings. For medical application, electrophoretic deposition (EPD) is now used for polymer (organic) and ceramic (inorganic) components at room temperature due to its simplicity, control of coating thickness and uniformity, low cost of equipment, ability to coat substrates of intricate shape and to supply thick films in composite form, high purity of deposits as well as no phase transformation during coating. Although extensive research has been conducted on polymer/inorganic composite coatings, only some studies have reported multifunctional properties, such as biological antibacterial activity, enhanced cell adhesion, controlled drug release ability, and mechanical properties. This review will focus on biodegradable coatings, including zien, chitosan, gelatin, cellulose loaded with antibacterial drugs/metallic ions/natural herbs on biostable substrates (PEEK/PMMA/PCL/ PLLA layers), which have the potential of multifunctional coating for metallic implants.

Antifouling Strategies-Interference with Bacterial Adhesion

“…Metals in various forms, coated on substrate surfaces, are well known for their antibacterial effects [80,81]. The main metals applied include silver, gold, copper, zinc, magnesium, calcium, cerium, strontium, nickel, titanium, europium, yttrium ions, and anions (such as selenium and fluoride) [82]. Silver can deactivate protein activities by interacting with thiol groups in proteins and interfere with transmembrane energy generation and ion transport by generating stable S-Ag bonds in the cell membrane [81].…”

A Brief Insight to the Electrophoretic Deposition of PEEK-, Chitosan-, Gelatin-, and Zein-Based Composite Coatings for Biomedical Applications: Recent Developments and Challenges

“…As discussed before, deposition of a polymeric substance alone results in poor mechanical strength of implants, so to avoid this, we incorporate some bio-ceramic particles to the polymer (e.g., BG, silica, HA, h-BN, etc.) [131]. These ceramic particles have their own issues of wear and brittleness.…”

“…EPD is the most facile and economical coating technique adopted for this purpos [131]. Ramos et al [83] performed experiments with zein/BG coating on 316L-SS in binary solutions of water and ethanol with varying proportions of both solutes and solvents The effect of varying voltage and deposition time was also recorded to optimize th process parameters.…”

3D printed porous titanium filled with mineralized UV-responsive chitosan hydrogel promote cell proliferation and osteogenesis in vitro

“…Chitosan (CS), derived from chitin, is a natural polysaccharide with controllable biodegradability and favorable biocompatibility. Methacrylic anhydride (MA) can interact with amidogen of CS through acylation reaction, resulting in the formation of photo-responsive CSMA under UV radiation [5,16,19].…”