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Bacterial cellulose (BC) is a highly pure and crystalline material generated by aerobic bacteria, which has received significant interest due to its unique physiochemical characteristics in comparison with plant cellulose. BC, alone or in combination with different components (e.g., biopolymers and nanoparticles), can be used for a wide range of applications, such as medical products, electrical instruments, and food ingredients. In recent years, biomedical devices have gained important attention due to the increase in medical engineering products for wound care, regeneration of organs, diagnosis of diseases, and drug transportation. Bacterial cellulose has potential applications across several medical sectors and permits the development of innovative materials. This paper reviews the progress of related research, including overall information about bacterial cellulose, production by microorganisms, mechanisms as well as BC cultivation and its nanocomposites. The latest use of BC in the biomedical field is thoroughly discussed with its applications in both a pure and composite form. This paper concludes the further investigations of BC in the future that are required to make it marketable in vital biomaterials.

Hydrogels are the most iconic class of soft materials and since their first report in the literature has attracted the attention of uncountable researchers. Over the past two decades, hydrogels become smart and sophisticated materials with plenty of applications possibilities. The biomedical research area has demonstrated a particular interest in hydrogels since they can be engineered from different polymers and due to their tunable properties. Moreover, hydrogels engineered from polymers extracted from biorenewable sources have been popularized in biomedical usages, as they are low-toxic, eco-friendly, biocompatible, easily accessible, and inexpensive at the same time. However, the multifaceted challenge is to find an ideal plant green hydrogel in the tissue engineering that can mimic critical properties of human tissues in terms of structure, function, and performance. In addition, these natural polymers are also idealized to be conveniently functionalized so that their chemical and physical behaviour can be manipulated for drug delivery and stem cell-guided tissue regeneration. Here, the most recent advances in the synthesis, fabrication and application of plant green hydrogels in biomedical engineering are reviewed. It covers essential and updated information about plant as green sources of biopolymers to be used in hydrogel synthesis, general aspects of hydrogels and plant green hydrogels and a substantive discussion regarding the use of such hydrogels in the biomedical engineering area. Furthermore, this review addresses and detail the present status of the field and, also, answer several important questions about the potential use of plant green hydrogels in advanced biomedical applications including therapeutic, tissue engineering, wound dressing, diagnostic, etc.

This study investigates the effects of calcium carbonate (CaCO3) nanoparticles on the mechanical and thermal properties and surface morphology of polycaprolactone (PCL)/chitosan nanocomposites. The nanocomposites of PCL/chitosan/CaCO3 were prepared using a melt blending technique. Transmission electron microscopy (TEM) results indicate the average size of nanoparticles to be approximately 62 nm. Tensile measurement results show an increase in the tensile modulus with CaCO3 nanoparticle loading. Tensile strength and elongation at break show gradual improvement with the addition of up to 1 wt% of nano-sized CaCO3. Decreasing performance of these properties is observed for loading of more than 1 wt% of nano-sized CaCO3. The thermal stability was best enhanced at 1 wt% of CaCO3 nanoparticle loading. The fractured surface morphology of the PCL/chitosan blend becomes more stretched and homogeneous in PCL/chitosan/CaCO3 nanocomposite. TEM micrograph displays good dispersion of CaCO3 at lower nanoparticle loading within the matrix.

Abstract:In the field of nanotechnology, the use of various biological units instead of toxic chemicals for the reduction and stabilization of nanoparticles, has received extensive attention. Among the many possible bio resources, biologically active products from fungi and yeast represent excellent scaffolds for this purpose. Since fungi and yeast are very effective secretors of extracellular enzymes and number of species grow fast and therefore culturing and keeping them in the laboratory are very simple. They are able to produce metal nanoparticles and nanostructure via reducing enzyme intracellularly or extracellularly. The focus of this review is the application of fungi and yeast in the green synthesis of inorganic nanoparticles. Meanwhile the domain of biosynthesized nanoparticles is somewhat novel; the innovative uses in nano medicine in different areas including the delivery of drug, cancer therapy, antibacterial, biosensors, and MRI and medical imaging are reviewed. The proposed signaling pathways of nanoparticles induced apoptosis in cancerous cells and anti-angiogenesis effects also are reviewed. In this article, we provide a short summary of the present study universally on the