Enhancing the Potential of PHAs in Tissue Engineering Applications: A Review of Chemical Modification Methods.

Polyhydroxyalkanoates (PHAs) are a family of polyesters produced by many microbial species. These naturally occurring polymers are widely used in tissue engineering because of their in vivo degradability and excellent biocompatibility. The best studied among them is poly(3-hydroxybutyrate) (PHB) and its copolymer with 3-hydroxyvaleric acid (PHBV).

Microspheres Based on Blends of Chitosan Derivatives with Carrageenan as Vitamin Carriers in Cosmeceuticals.

Chitosan (CS) has a natural origin and is a biodegradable and biocompatible polymer with many skin-beneficial properties successfully used in the cosmetics and pharmaceutical industry. CS derivatives, especially those synthesized via a Schiff base reaction, are very important due to their unique antimicrobial activity. This study demonstrates research results on the use of hydrogel microspheres made of [chitosan--poly(ε-caprolactone)]--(ĸ-carrageenan)], [chitosan-2-pyridinecarboxaldehyde--poly(ε-caprolactone)]--(ĸ-carrageenan), and chitosan-sodium-4-formylbenzene-1,3-disulfonate--poly(ε-caprolactone)]--(ĸ-carrageenan) as innovative vitamin carriers for cosmetic formulation.

Bactericidal Chitosan Derivatives and Their Superabsorbent Blends with ĸ-Carrageenan.

The aim of this work is research dedicated to the search for new bactericidal systems for use in cosmetic formulations, dermocosmetics, or the production of wound dressings. Over the last two decades, chitosan, due to its special biological activity, has become a highly indispensable biopolymer with very wide application possibilities. Reports in the literature on the antibacterial effects of chitosan are very diverse, but our research has shown that they can be successfully improved through chemical modification.

Bactericidal Biodegradable Linear Polyamidoamines Obtained with the Use of Endogenous Polyamines.

The work presents the synthesis of a series of linear polyamidoamines by polycondensation of sebacoyl dichloride with endogenous polyamines: putrescine, spermidine, spermine, and norspermidine-a biogenic polyamine not found in the human body. During the synthesis carried out via interfacial reaction, hydrophilic, semi-crystalline polymers with an average viscosity molecular weight of approximately 20,000 g/mol and a melting point of approx. 130 °C were obtained.

Biodegradable Block Poly(ester amine)s with Pendant Hydroxyl Groups for Biomedical Applications.

The article presents the results of the synthesis and characteristics of the amphiphilic block terpolymers, built of a hydrophilic polyesteramine block, and hydrophobic blocks made of lactidyl and glycolidyl units. These terpolymers were obtained during the copolymerization of L-lactide with glycolide carried out in the presence of previously produced macroinitiators with protected amine and hydroxyl groups. The terpolymers were prepared to produce a biodegradable and biocompatible material containing active hydroxyl and/or amino groups, with strong antibacterial properties and high surface wettability by water.

Triple-Shape Memory Behavior of Modified Lactide/Glycolide Copolymers.

The paper presents the formation and properties of biodegradable thermoplastic blends with triple-shape memory behavior, which were obtained by the blending and extrusion of poly(l-lactide--glycolide) and bioresorbable aliphatic oligoesters with side hydroxyl groups: oligo (butylene succinate--butylene citrate) and oligo(butylene citrate). Addition of the oligoesters to poly (l-lactide--glycolide) reduces the glass transition temperature (T) and also increases the flexibility and shape memory behavior of the final blends. Among the tested blends, materials containing less than 20 wt % of oligo (butylene succinate--butylene citrate) seem especially promising for biomedical applications as materials for manufacturing bioresorbable implants with high flexibility and relatively good mechanical properties.

Synthesis and Properties of Bioresorbable Block Copolymers of l-Lactide, Glycolide, Butyl Succinate and Butyl Citrate.

The paper presents the course of synthesis and properties of a series of block copolymers intended for biomedical applications, mainly as a material for forming scaffolds for tissue engineering. These materials were obtained in the polymerization of l-lactide and copolymerization of l-lactide with glycolide carried out using a number of macroinitiators previously obtained in the reaction of polytransesterification of succinic diester, citric triester and 1,4-butanediol. NMR, FTIR and DSC were used to characterize the materials obtained; wettability and surface free energy were assessed too.

Influence of Radiation Sterilization on Properties of Biodegradable Lactide/Glycolide/Trimethylene Carbonate and Lactide/Glycolide/ε-caprolactone Porous Scaffolds with Shape Memory Behavior.

The aim of the study was the evaluation of gamma irradiation and electron beams for sterilization of porous scaffolds with shape memory behavior obtained from biodegradable terpolymers: poly(l-lactide--glycolide--trimethylene carbonate) and poly(l-lactide--glycolide--ɛ-caprolactone). The impact of mentioned sterilization techniques on the structure of the scaffolds before and after the sterilization process using irradiation doses ranged from 10 to 25 kGy has been investigated. Treatment of the samples with gamma irradiation at 15 kGy dose resulted in considerable drop in glass transition temperature (T) and number average molecular weight (M).

Scaffolds with shape memory behavior for the treatment of large bone defects.

The aim of the presented study was preparation, analysis of properties, and in vitro characterization of porous shape-memory scaffolds, designed for large bone defects treatment using minimally invasive surgery approach. Biodegradable terpolymers of l-lactide/glycolide/trimethylene carbonate (LA/GL/TMC) and l-lactide/glycolide/ε-caprolactone (LA/GL/Cap) were selected for formulation of these scaffolds. Basic parameters of shape memory behavior (i.