Biocompatibles, aliphatic polyesters

Bacterial polyesters (polyhydroxy alkanoates) Poly(3-hydroxy butyrate), poly(3-hydroxy valerate) Some micro-organisms, especially bacteria, can synthesise biocompatible aliphatic polyesters, which have potential in medical applications. 

The idea of using polymers as binders for particulate bioceramics to prepare biocomposites with improved processing and retention characteristics and to overcome the problem of poor mechanical properties was reported. Poly(rac-lactide) (PDLLA) is a thermoplastic biodegradable, resorbable, and biocompatible aliphatic polyester, which in recent years received significant attention in the biomedical research field. It was also generally viewed as a polymer of the future because... 

Poly(p-dioxanone) (PPDO), one of the biodegradable and biocompatible aliphatic polyesters, has high flexibility, good tensile strength and mechanical properties. Due to its good biocompatibility and physical properties, PPDO has been considered as a candidate not only for medical uses but also for universal uses such as films, molded products, laminates, foams, non-woven materials,... 

PCL is a bioresorbable and biocompatible aliphatic polyester that is generally used in pharmaceutical products and wound dressings. In addition, PCL nanofibrous matrices coated with collagen support cell growth or make the three-dimensional structured multilayer of PCL nanofibers and collagen nanofibers suitable for blood... 

The broad range of biodegradable and biocompatible aliphatic polyesters shown in Fig. 4.1 have been prepared over the last forty years. Among them, poly(e-... 

Many kinds of nonbiodegradable vinyl-type hydrophilic polymers were also used in combination with aliphatic polyesters to prepare amphiphilic block copolymers. Two typical examples of the vinyl-polymers used are poly(/V-isopropylacrylamide) (PNIPAAm) [149-152] and poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) [153]. PNIPAAm is well known as a temperature-responsive polymer and has been used in biomedicine to provide smart materials. Temperature-responsive nanoparticles or polymer micelles could be prepared using PNIPAAm-6-PLA block copolymers [149-152]. PMPC is also a well-known biocompatible polymer that suppresses protein adsorption and platelet adhesion, and has been used as the hydrophilic outer shell of polymer micelles consisting of a block copolymer of PMPC -co-PLA [153]. Many other vinyl-type polymers used for PLA-based amphiphilic block copolymers were also introduced in a recent review [16]. 

Poly(l,4-dioxan-2-one) (PDON), a well-known aliphatic polyester with outstanding biocompatibility, bioabsorbability and good flexibility (34), has received the approval of the FDA to be used as suture material in gynecology (35). However, Haruo Nishida (36) reported that the M of PDON was 1800... 

Poly(butylene succinate) (PBS) is an important member of biodegradable aliphatic polyester family. PBS and related copolymers have shown considerable promise for uses as environmentally biodegradable thermoplastics, as well as bioabsorbable/biocompatible medical materials (/). In both cases, practical applications require that the polymer possess a high molecular weight (M >20,000) so that it can have useful mechanical properties. 

Aliphatic polyesters (such as PLA, polyglycolic acid and their copolymers) are the most important class of biocompatible polymers used in biomedical applications. This class of polymers has shown superior properties over conventional polymers, such as excellent biocompatibility, biodegradation, and thermal, physical and mechanical properties, which make them suitable for applications in drug delivery and tissue engineering [19-21]. 

Drug delivery systems based on biodegradable aliphatic polyesters have advanced remarkably over the past few decades. Commonly used polymers such as poly(e-caprolactone) (PCL), poly (lactide acid) (PLA), and poly (lactic-co-glycolic acid) (PLGA) are FDA approved and well known for their biodegradability, biocompatibility, and non-toxic properties, which make them suitable as matrices for controlled release drug delivery systems. 

Aliphatic polyesters are the most representative examples of biodegradable polymeric materials. Poly(3-hydroxyalkanoate)s, PHA, are well known biocompatible and biodegradable polyesters that are produced by various microorganisms as carbon and energy reserves. The physical properties of PHAs vary from crystalline-brittle to soft-sticky materials depending on the length of the side aliphatic chain on p carbon ... 

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