Cellulose and its derivatives: towards biomedical applications

© 2021, The Author(s).Cellulose is the most abundant polysaccharide on Earth. It can be obtained from a vast number of sources, e.g. cell walls of wood and plants, some species of bacteria, and algae, as well as tunicates, which are the only known cellulose-containing animals. This inherent abundance naturally paves the way for discovering new applications for this versatile material. This review provides an extensive survey on cellulose and its derivatives, their structural and biochemical properties, with an overview of applications in tissue engineering, wound dressing, and drug delivery systems. Based on the available means of selecting the physical features, dimensions, and shapes, cellulose exists in the morphological forms of fiber, microfibril/nanofibril, and micro/nanocrystalline cellulose. These different cellulosic particle types arise due to the inherent diversity among the source of organic materials or due to the specific conditions of biosynthesis and processing that determine the consequent geometry and dimension of cellulosic particles. These different cellulosic particles, as building blocks, produce materials of different microstructures and properties, which are needed for numerous biomedical applications. Despite having great potential for applications in various fields, the extensive use of cellulose has been mainly limited to industrial use, with less early interest towards the biomedical field. Therefore, this review highlights recent developments in the preparation methods of cellulose and its derivatives that create novel properties benefiting appropriate biomedical applications

In vivo electromechanical reshaping of ear cartilage in a rabbit model: a minimally invasive approach for otoplasty.

ObjectiveTo report the first successful study to date of in vivo electromechanical reshaping of ear cartilage in a rabbit model.MethodsEars of New Zealand white rabbits were reshaped using percutaneous needle electrode electromechanical reshaping (5 V for 4 minutes) and were then bolstered for 4 weeks. Ten ears were treated, with 2 undergoing sham procedures and serving as controls. The treatment was performed using a platinum array of electrodes consisting of 4 parallel rows of needles inserted across the region of flexures in the ear. After 4 weeks, the animals were killed, and the ears were photographed and sectioned for conventional light microscopy and confocal microscopy (live-dead fluorescent assays).ResultsSignificant shape change was noted in all the treated ears (mean, 102.4°; range, 87°-122°). Control ears showed minimal shape retention (mean, 14.5°; range, 4°-25°). Epidermis and adnexal structures were preserved in reshaped ears, and neochondrogenesis was noted in all the specimens. Confocal microscopy demonstrated a localized zone of nonviable chondrocytes (<2.0 mm in diameter) surrounding needle sites in all the treated ears.ConclusionsElectromechanical reshaping can alter the shape of the rabbit auricle, providing good creation and retention of shape, with limited skin and cartilage injury. Needle electrode electromechanical reshaping is a viable technique for minimally invasive tissue reshaping, with potential applications in otoplasty, septoplasty, and rhinoplasty. Further studies to refine dosimetry parameters will be required before clinical trials