Synthesis and characterization of novel thermoresponsive‐co‐biodegradable hydrogels composed of N‐isopropylacrylamide, poly(L‐lactic acid), and dextran

Abstract

A series of novel multifunctional hydrogels that combined the merits of both thermoresponsive and biodegradable polymeric materials were designed, synthesized, and characterized. The hydrogels were copolymeric networks composed of Nisopropylacrylamide (NIPAAM) as a thermoresponsive component, poly(L-lactic acid) (PLLA) as a hydrolytically degradable and hydrophobic component, and dextran as an enzymatically degradable and hydrophilic component. The chemical structures of the hydrogels were characterized by an attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) technique. The hydrogels were thermoresponsive, showing a lower critical solution temperature (LCST) at approximately 32°C, and their swelling properties strongly depended on temperature changes, the balance of the hydrophilic/hydrophobic components, and the degradation of the PLLA component. The degradation of the hydrogels caused by hydrolytic cleavage of ester bonds in the PLLA component was faster at 25°C below the LCST than at 37°C above the LCST, determined by the ATR-FTIR technique. Due to their multifunctional properties, the designed hydrogels show great potential for biomedical applications, including drug delivery and tissue engineering.

Synthesis and characterization of a novel polymeric hydrogel based on hydroxypropyl methyl cellulose grafted with polyacrylamide

“…Since their water content and mechanical properties can be controlled by incorporating different contents of hydrophilic and hydrophobic segments, hydrogels have been used in a wide range of biological, medicinal and pharmaceutical applications (Dong et al 2008;Finne and Albertsson 2003;Huang et al 2004;Kurian and Kennedy 2002a, b;Lu et al 2008;Meyer et al 2002;Peppas et al 2006;Slaughter et al 2009;Vishalakshi and Ghosh 2003;Zhang and Chu 2002). Biodegradable hydrogels play an important role in controlled drug delivery (Gils et al 2009;Soppirnath and Aminabhavi 2002).…”

Porous Thermoresponsive-co-Biodegradable Hydrogels as Tissue-Engineering Scaffolds for 3-Dimensional In Vitro Culture of Chondrocytes

“…We synthesized and extensively characterized non-porous hydrogels with the same feeding chemical composition in a previous study. 30 In the current study, primary chondrocytes isolated from the caudal part of embryonic chick sterna were seeded inside the porous thermoresponsive and biodegradable hydrogels at room temperature, below the LCST of the hydrogels. The evolution of the chondrocyte development inside the hydrogels at 378C (above the LCST of the hydrogels) was evaluated by quantifying chondrocyte marker genes' messenger ribonucleic acid (mRNA) using real-time reverse-transcriptase polymerase chain reaction (RT-PCR) every week for 1 month.…”

Injectable hydrogels

“…Another method allowing for gel degradation is cross-linking NIPAAm-based polymer chains with degradable cross-linkers such as poly(lactic acid), 42 dextran, 42,43 or peptide FIGURE 1 Physical gelation via stimuli-responsive polymer is one mechanism used to create injectable hydrogels. This example shows a temperature-responsive N-isopropylacrylamide copolymer undergoing a phase transition on change of temperature.…”