Role of carboxyl pendant groups of medium chain length poly(3‐hydroxyalkanoate)s in biomedical temporary applications

Abstract

The poly(3-hydroxyoctanoate) (PHO) is a biodegradable polyester containing hydrophobic side chains. One way to obtain more hydrophilic polyester consisted in the introduction of polar groups in the side chains. Carboxyl groups (PHO 75 COOH 25 ) were introduced by chemical modifications. The role of carboxyl groups was investigated in the first part as potential support for cell seeding by studying the cell adhesion and proliferation, and in the second part as potential drug carrier by comparing the abilities of PHO and PHO 75 COOH 25 to form degradable particles. Measurements of human bladder RT112 cells adhesion were done with or without collagen IV. Adhesive RT112 cells were counted by a colorimetric MTT test. The results showed that the COOH pendant groups of PHO 75 COOH 25 films promoted cell adhesion after 4 h of incubation. The proliferation of cells is not improved after 4 days of incubation because of a reorganization of macromolecular chains and reorientation of COOH groups. This surface restructuration when the film was in contact with water was showed by contact angle measurements. We showed that the presence of COOH groups modified the hydrophobic/hydrophilic balance and enhanced the formation of particles. Stable lyophilisable particles were then obtained with diblock copolymer P(HO 75 COOH 25 -b-CL); the caprolactone block (CL) was necessary to improve particles stability. The results showed that the release of doxorubicin from the particles is enhanced in presence of hydrophilic and degradable block (PHO 75 COOH 25 ). It was possible to obtain a degradable functional polyester based on PHO with carboxyl pendant groups to improve degradation rate by simple hydrolysis required for drug delivery systems.

Adhesion and proliferation of human bladder RT112 cells on functionalized polyesters

“…After 72 hours of incubation a decrease of cell viability can be explained by a cytotoxic effect of PHOD-COOH. As described previously a partial reorganization of the polymeric material during the 72 hours of incubation can lead to the presence of carboxylic groups at the surface and an increased hydrophilic surface [33]. As seen earlier bovine serum albumin interacts preferentially with hydrophobic surfaces.…”

“…These results could be explained by the presence at the film surface of a few quantities of carboxylic groups and PEG graft oligomers, which does not decrease significantly the materials hydrophobicity. Indeed the most probable explanation is the internalization of the polar groups during the film preparation process in chloroform as apolar solvent [33]. Films have been prepared and sterilized under UV-C germicidal lamp in the laminar flow cabinet.…”

Polyhydroxyalkanoates as biomaterials

“…The drug release profile of this polymer recorded an increase in doxorubicin release and cell proliferation studies also showed better cell proliferation. 50 In addition to drugs, PHAs were also studied for releasing nucleic acids and proteins; for example; cationic PHA was synthesized to obtain polyIJhydroxyoctanoate)-co-(hydroxy-11-(bisIJ2-hydroxyethyl)amino)-10-hydroxyundecanoate) to immobilize plasmid DNA and its delivery was monitored, 51 and inactive extracellular PHA depolymerase and mcl PHA polyij(3-hydroxyoctanoate)-co-(3-hydroxyhexanoate)] were used for immobilization and delivery of proteins. 52 High performance PHAs were studied as transdermal drug delivery systems (TDDS), which are composed of monomers like 3-hydroxyhexanoic acid and 3-hydroxyoctanoic acid.…”

Antioxidant Network Based on Sulfonated Polyhydroxyalkanoate and Tannic Acid Derivative

“…One of the first studies concerning the chemical modification of PHAs started with the production of poly(3-hydroxyoctanoate- co -3-hydroxyundecenoate) (PHOU) that contained unsaturated groups in the side chains [ 10 , 11 ]. The chemical modifications of the unsaturated groups of PHOU have already been reported [ 12 , 13 , 14 , 15 , 16 , 17 ]. The introduction of polar groups, such as hydroxyl, carboxylic and ammonium groups, makes it possible to modify the hydrophilic/hydrophobic balance of the polymer.…”