A careful selection of monomers for biomaterial syntheses is essential for determining and controlling the functionality and biocompatibility of the biomaterials to be produced. Synthetic polyester elastomers based on molecules that are endogenous to the human metabolism have been designed [1]. In earlier studies, several investigators have reported elastic polyesters based on citric acid, in particular polyoctanediol citrate (POC) [2], poly(alkenylene maleate citrate) [3], poly(xylitol-co-citrate) [4] and poly(mannitol citric dicarboxylate) [5]. Although a number of biodegradable elastomers have been developed, most of them require complex and expensive synthetic procedures, which translate into higher manufacturing costs and hinder the commercial and clinical implementation of their use in tissue engineering [6]. Also, as more stringent material requirement in tissue engineering is made, there is a continuous need for newer materials’ design and synthesis [7]. The objective of the present work is to design polyesters using citric acid, sebacic acid, itaconic acid and 1,12-dodecanediol. To synthesize the polyesters by melt condensation, thermal polyesterification technique without using catalysts or coreagents, making this method attractive for the synthesis of polyesters useful in medical applications. The chosen monomers are expected to provide the polyesters with physico-chemical properties that could be significantly impact the degradation and biocompatibility of the synthesized polyesters.
Materials and Methods
Results and Discussion
Synthesis and Characterization of the polyesters
The copolyesters were synthesized by melt condensation of monomers based on the schematic representation in Figures 1a and 1b.
The FT-IR spectra ...
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...en BG, Tse MY, Turner ND, Knight DK, Pang SC (2006) In vivo degradation behavior of photo-cross-linked star-poly(ε-caprolactone-co-D,L-lactide)elastomers. Biomacromolecules 7: 365-372.
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25. Birdi K (1981) Cell adhesion on solids and th
Solid triphenylmethanol (0.200 g, 0.768 mmol) and sulfuric acid (2 mL) were added to a reaction tube, which was then ground using a glass rod until it dissolved and turned a dark orange color. The mixture was then added dropwise via a glass pipette into another reaction tube containing methanol (1 mL). An extra amount of methanol (2 mL) was used to transfer the rest of the contents of the first reaction tube. Formation of crystals was facilitated by scratching the side of the tube and adding additional methanol until the color changed to an off-white color. The contents of the tube were then vacuum filtered with water and the resulting crude product was weighed and then recrystallized using hot methanol to form triphenylmethyl methyl ether (0.051 g, 0.186 mmol, 24.2%). The melting point was 81 – 83˚
In the end, regardless of the scientific methods that could be used to treat different diseases and more specifically retinal degeneration, many studies should be conducted determine the potential clinical application of photobiomodulation with NIR for treatment of different injuries and disorders.
Alumina and zirconia ceramics have been widely used in orthopaedic hip replacements for the past 30 years. The advantage of using these was lower wear rates than those observed using polymers and metals. Because of the ionic bonds and chemical stability of ceramics, they are relatively biocompatible and therefore more preferable to use than metals and polymers. Alumina is most commonly used as a femoral head component instead of a metal in a hip prosthesis because this would reduce the polyethylene wear that is generated. Alumina is a desirable biomaterial to use in hard tissue implants because of characteristics like excellent wear resistance, high hardness, bio inert, low abrasion rate and good frictional behaviour. Furthermore, it has excellent surface finish as well as high fatigue streng...
16. Wang, Yadong. "An Anti-angiogenic Reverse Thermal Gel as a Drug-Delivery System for Age-Related Wet Macular Degeneration." Macromolecular Bioscience: 464-469. Web. 1 May 2014.
Schulman, Joshua M., and David E. Fisher. "Abstract." National Center for Biotechnology Information. U.S. National Library of Medicine, 28 Aug. 0005. Web. 24 Apr. 2014.
The Crystallinity of Kevlar Polymer strands, contributes to the unique strength and stiffness of the material. Kevlar is very similar to other common synthetic polymers, including Nylon, Teflon and Lycra. In all Polated to strength. Aromatic refers to the Carbon atoms attached in a ring, and Amides refers to a group of Carbon, Nitrogen and Hydrogen atoms. Kevlar fiber is therefore a “Polyaromatic amide”, as it has a high breaking strength.
Dialysis tubing is made from regenerated cellulose or cellophane, and is used in clinical circumstances to ensure that molecule have a filtered flow, and that larger solute molecules do not enter the dialysis tubing (Alberts, 2002). Like a cell membrane, dialysis tubing has a semi-permeable membrane, which allows small molecule to permeate through the membrane. Thus, the dialysis tubing mimics the diffusion and osmosis processes of the cell membrane (Alberts, 2002). Although the dialysis tubing has a semi-permeable membrane, which mimics a cell, its structure is different. The me...
Our own immune system such as macrophages help in restoring the damage in the heart for example, damage caused by myocardial infarction. Macrophages responsibilities are to clear the infarcted area and activate other cells, such as fibroblasts, endothelial cells and progenitor cells to help the healing process of the blood vessels (Mercola et al. 2011). Tissue regenerative in today’s world uses the stem cell technology to repair, replace and regenerate the cells of the injured organ or tissues. It is a combination of engineering principles and life sciences in order to create something that able to proliferate and regenerate as well as sustaining and improving its functions. This purpose can be achieved by applying functional cells, scaffolds supplementary, stimulate the growth and signal molecules to needed areas. The scaffold delivers as physical support for the cells as well as to function as organizer guiding the cell growth and differentiation (Leor et al. 2005).
The most common form of polyethylene is petroleum based or olefins based; as before mentioned polyethylene compounds have a wide commercial applicability and are made from non-renewable resources (Harding, Dennis, von Blottnitz, Harrison, & S.T.L., 2007). Its manufacturing processes are regarded as energy intensive and release significant amount of CO2 and heat into the atmosphere (Broderick, 2008). Next a little more detailed description of polyethylene’s production processes will be presented, with a focus on the way the material inputs are extracted and synthesized.
We have discussed various cell-wall associated biopolymers. Select one irregular biopolymer and describe its structural arrangements in the context of molecular and supramolecular level -- draw sketches. Indicate an experimental technique that could show how the biopolymer may respond to abiotic/environmental stresses
...logy. In L. R. Castilho, A. M. Moraes, E. F. P. Augusto & M. Butler (Eds.), Animal cell technology: From biopharmaceuticals to gene therapy (pp. 1-12). Abingdon, OX: Taylor & Francis Group.
The future for the total artificial heart with respect to using polyurethanes comes in the form of thermoplastic polyurethane (TPU), also known as polyurethane elastomers that have molecular structures similar to that of human proteins. TPUs have slower protein absorption (protein absorption is the beginning of the blood clotting process) this makes TPUs ideal candidates in the manufacturing of the total artificial heart because it provides more adhesive strength and mimics certain elements within the body. Hence, biomedical polyurethanes can lead the way to eliminate some acute health challenges that the total artificial heart currently faces. By virtue of their range of properties, polyurethanes and their new applications will continue to play an important role in the future of the total artificial heart.
The solvent should be easily removed from the purified product, not react with the target substances, and should only dissolve the target substance near it’s boiling point, but none at freezing. A successful recrystallization uses minimum amount of solvent, and cools the solution slowly, if done to fast, many impurities will be left in the crystals. Using the correct solvent, in this case ice water and ethyl acetate, the impurities in the compound can be dissolved to obtain just the pure compound. A mixed solvent was used to control the solubility of the product. The product is soluble in ethanol an insoluble in water. Adding water reduced solubility and saturates the solution and then the crystals
All polymer host has some major advantages for which their application in electrochemical devices are still continuing. Also these polymer have some disadvantages and to improve the
Cell Adhesion: When transmembrane glycoproteins mediate interactions between cells which allow the cells to attach to a surface, a substrate, or another cell.