Bioresorbable materials

D radation rate of bioresorbable materials Edited by E J. Buchanan... 

Suuronen R. and Lindqvist C. (2002), Bioresorbable materials for bone fixation review of biological concepts and mechanical aspects, CraniomaxUlofadal Reconstructive and Corrective Bone Surgery, Section II, 113-123. 

Note This chapter was previously published as Chapter 3 Synthetic bioresorbable polymers by R. E. Cameron and A. Kamvari-Moghaddam, originally published in Degradation rate of bioresorbable materials predication and evaluation, ed. F. J. Buchanan, Woodhead Publishing Limited, 2008 ISBN 978-1-84569-329-9. 

Li, S. and Vert, M., Hydrolytic degradation of coral/poly(DL-lactic acid) bioresorbable material. Journal of Biomaterials Science - Polymer Edition 7, 817-827 (1996). 

Porous PLA/PGA copolymer has been proposed as a successful biodegradable matrix for tissue engineering for both bone and cartilage regeneration and osteoblasts are observed to adhere better to and produce more extracellular matrix proteins on PLA/PGA copolymer than on other osteocompatible bioresorbable materials. 

Next-generation biomaterials should combine bioactive and bioresorbable materials, which mimic the natural function of bone and activate in vivo mechanisms of tissue regeneration. However, to date, an injectable, bioactive, and strong scaffold for stem cell encapsulation and bone engineering is yet to be developed. 

Li, S., 2008. In-vitro physicochemical test methods to evaluate the bioresorbability of polymeric biomaterials. In Buchanan, F. (Ed.), Degradation Rate of Bioresorbable Materials Prediction and Evaluation. Woodhead Publishing Ltd, Cambridge, pp. 117—144. 

Cameron, R.E., Kamvari-Moghaddam, A., 2008. Synthetic bioresorbable polymers. Degradation Rate of Bioresorbable Materials. Woodhead Pubishing Limited, Cambridge England, pp. 43 6. 

The development of soft-tissue engineering needs bioresorbable materials exhibiting elastomeric properties. Elastomeric polyurethane (PU) vascular grafts can withstand the action of stress and load and undergo an elastic recovery with little or no hysteresis. In recent years, biocompatible and biodegradable segmented polyurethanes (SPUs) have been studied for applications in the tissue engineering field. 

Buchanan, F., 2008. Degradation Rate of Bioresorbable Materials Prediction and Evaluation. 

The choice of the right suppliers for raw materials is critical because validation of a bioresorbable polymer includes the characteristics of all the suppliers involved in the production process, ie, their quality systems and certifications. An unreliable supplier represents a possible source of issues when producing a device under regulatory approval. For example, a supplier could fail obliging the company to begin a validation process for the new supplier, the quality of the raw material could be erratic, or the supply of a determined material could be discontinued [20]. Moreover, in the past years the number of suppliers of bioresorbable materials did not increase as expected,... 

Paul W, Sharma CP. Natural bioresorbable pol3miers. In Buchanan FJ, editor. Degradation rate of bioresorbable materials prediction and evaluation. Cambridge, England Woodhead Pubhshing Limited 2008. p. 67—94. 

Intravenous administration has most the restrictions because the formulations must be, as much as possible, biocompatible and also biodegradable to prevent their accumulation in the body (ie, they must be bioresorbable materials). The size of the carriers that are used must satisfy specific characteristics. The injected materials must be less than 300 nm to avoid their rapid elimination by the liver and spleen. In addition, the diameters of these carriers should preferably be larger than 20 nm to avoid rapid elimination by the kidneys (see Fig. 12.1) [2]. In addition, the surface of these materials must be properly functionalized to avoid interaction with the immune system (and then rapid NP elimination), while also increasing the interaction with the target tissues [3]. 

Of primary importance to both tissues is their structural organization and self-repair capacity. However, once they are injured by critical-sized lesions, healing is often inadequate and functional recovery becomes suboptimal. In such scenarios, bioresorbable materials offer remarkable opportunities to restore the native tissues or replace them with engineered substitutes. 

Bioresorbable materials have been administered in preclinical studies either alone or as delivery vehicles for cells, growth factors, and biological moieties. The major advantages of these systems can be summarized as delivery of drugs at a constant rate, drug protection, drug control pharmacokinetics, minimization of possible side effects, better efficacy, and enhanced patient compliance [37] (Fig. 19.3). 

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