The appropriate capability of handling several forces exerted inside the mouth, and preventing the adhesion and proliferation of oral microorganisms are among the most vital factors for achieving effective alternative dental materials to the damaged native. Nevertheless, lack of mechanical and antimicrobial properties of dental resins hinders their use in most clinical applications in dentistry. In the present study, the main aim was to provide bioepoxy composite biomaterials that could meet the required mechanical and antibacterial properties for dental related fields. Herein, highly biocompatible epoxy and hybrid reinforcing materials were utilised to produce a composite material, which could have features resembling those of original dental parts. Various weight fractions of nanosilver/nano-alumina particles at 1, 2, and 3 wt% were incorporated into the bioepoxy for improving the mechanical and antibacterial characteristics of the biocompatible epoxy resin. Three-point bending and Izod impact tests were performed to evaluate the flexure and impact strengths of the obtained nanocomposites. The morphology of pristine bioepoxy and nanoparticle reinforced bioepoxy composites was characterized by scanning electron microscopy. The influence of these fillers on the bioepoxy resin antibacterial sensitivity was assessed using the agar diffusion technique. Nanofiller contents have been revealed to have a remarkable role to play in tuning the mechanical properties of the nanocomposites; the flexure strength and modulus were higher when the total ratio of hybrid reinforcement was 2 wt%. In contrast, the addition of higher percentage of hybrid nanoparticles could cause deterioration in the flexure characteristics of nanocomposites, yet they were better than those of pristine epoxy. Regarding the impact strength, the enhancement in this property was only observed for the composite containing 1 wt% of AgNps-Al2O3; the impact strength was dropped gradually beyond this ratio. The antibacterial effectiveness of the nanocomposites was demonstrated to positively depend on the increase in AgNps mass fraction. Among all evaluated unmodified and modified bioepoxy, the nanocomposite containing 2.5 wt% of AgNps had the higher antibacterial activity against Escherichia coli and Staphylococcus aureus. Based on the attainable outcomes, the prepared composites, particularly at moderate levels of Al2O3-AgNps, could provide biocomposites having the potential to be utilised in several biomedical fields, particularly in dental technology.

The utilisation of metals and alloys in the biomedical field was and is still of immense importance for human life. Typically, the materials used for metallic biomedical applications, particularly those are implanted in vivo, provide appropriate mechanical and biological properties that allow them to accomplish the purpose for which they are used. Nonetheless, there are some inherent limitations impede the optimal use of these materials. One of the most crucial determinants is corrosion, which results in several other problems such as the formation of toxic substances that can not only cause necrosis of the cells attached to the implant, these toxins could also be carried by blood into body tissues and organs. This in turn leads to dire consequences on patient's life. Although a wide variety of approaches may be available to address the corrosion issue, it is alleged that coating these metals and alloys with polymers, especially the conductive ones, is among the best strategies in this regard. This review will highlight the latest developments in using conductive polymers including polypyrrole, polyaniline, polythiophene and their composites in order to enhance biocompatibility, mechanical properties and most importantly corrosion protection performance of metallic implants. The findings obtained from coating 316L stainless steel, titanium and magnesium alloys, which have been widely manipulated in biomedical field as long and short-term implants, will be evaluated.

Chronic diseases such as peripheral vascular and arteriosclerosis, wars, terrorist attacks, natural disasters, and traffic collisions are the major causes of the high demand for prostheses. The inadequacy of the typically used materials at reasonable prices and the high stiffness of these materials, which can negatively influence socket-limb load transfer, imply an urgent need to find alternatives to the existing prosthetic sockets. This work aims to use renewable, low-hazard, and low-cost natural flax fibres and seashell nanoparticles as substitutes for conventional reinforcement materials for prosthetic sockets. Seashell nanoparticles of 1, 3, and 5 weight fractions and 3 layers of flax fibres were integrated into biobased epoxy. Tensile and flexural properties of modified and unmodified specimens were assessed, and the finite element technique (ANSYS-20) was utilised to analyse and evaluate the mechanical characteristics of the specimens by observing the stress and total deformation. Here, all fabricated nanocomposites provided tensile and flexural strength higher than that of additive-free biobased epoxy. In addition, hybrid nanocomposites fabricated from 3 layers of flax fibres and 3 wt% of seashell nanoparticles were revealed to have the highest mechanical properties compared with unmodified resin and biobased epoxy filled with other percentages of the reinforcement. These findings were further validated numerically in which the total deformation was shown to decrease after the addition of 3 wt% of these nanoparticles within the nanocomposites. Moreover, the antibacterial activity proved its superb antimicrobial performance against various pathogenic microorganisms, namely, Staphylococcus aureus and E. coli. Accordingly, the fabricated composite systems are suggested to be an appropriate candidate for forming prosthetic sockets. These composites have promising mechanical and antibacterial properties, and they are made of affordable and available materials, which can be a suitable option, particularly in poor countries due to the fact that advanced technologies may require a substantial amount of money for equipment, surgery fees, and medical care.

The utilisation of metals and alloys in the biomedical field was and is still of immense importance for human life. Typically, the materials used for metallic biomedical applications, particularly those are implanted in vivo, provide appropriate mechanical and biological properties that allow them to accomplish the purpose for which they are used. Nonetheless, there are some inherent limitations impede the optimal use of these materials. One of the most crucial determinants is corrosion, which results in several other problems such as the formation of toxic substances that can not only cause necrosis of the cells attached to the implant, these toxins could also be carried by blood into body tissues and organs. This in turn leads to dire consequences on patient's life. Although a wide variety of approaches may be available to address the corrosion issue, it is alleged that coating these metals and alloys with polymers, especially the conductive ones, is among the best strategies in this regard. This review will highlight the latest developments in using conductive polymers including polypyrrole, polyaniline, polythiophene and their composites in order to enhance biocompatibility, mechanical properties and most importantly corrosion protection performance of metallic implants. The findings obtained from coating 316L stainless steel, titanium and magnesium alloys, which have been widely manipulated in biomedical field as long and short-term implants, will be evaluated.

Bone defects and disorders include trauma, osteonecrosis, osteoporosis, bone tumours, arthritis rheumatoid, osteosarcoma, and iatrogenic injury. Obtaining a composite material with characteristics that mimic what bones in the human body have is a vital target for the purpose of replacing or repairing damaged bones. The key objective of this study was to develop a composite having mechanical and biological properties that resemble to a large extent native bone features. Highly biocompatible epoxy resin was reinforced by various weight fractions of seashell nanoparticles. The morphologies of the pristine bioepoxy, seashell-bioepoxy, and hydroxyapatite-bioepoxy composites were observed by scanning electron microscopy. Moreover, the mechanical properties were examined by the means of tension and Izod impact tests. Besides, the influence of seashell and hydroxyapatite nanoparticles on the bioepoxy chemical structure and thermal properties was also evaluated using Fourier transform infrared spectroscopy and differential scanning calorimetry technique, respectively. The tensile strength, modulus of elasticity, and impact strength of the seashell nanoparticle-reinforced bioepoxy were revealed to be higher than those of the unmodified bioepoxy and were significantly depended on the filler content. When the mass fraction of the reinforcement was 7 wt%, the improvement in the tensile strength, modulus of elasticity, and impact strength was around 46.7%, 37%, and 57%, respectively, compared to that of blank bioepoxy. In addition, these properties were higher for the composites loaded with seashell nanoparticles than those filled with commercially available hydroxyapatite nanoparticles. An enhancement in glass transition temperature for the bioepoxy after modification with both of these nanofillers was also achieved. All these features make these kinds of composites a promising option that could be used in the orthopaedic field. Furthermore, the use of seashell nanoparticles may reduce the cost of the resulted composite and alleviate the negative consequences of large quantity by-product waste seashells on the environment.