Chitosan Membranes Exhibiting Shape Memory Capability by the Action of Controlled Hydration

Abstract

Abstract:Chitosan membranes can undergo a glass transition at room temperature triggered by hydration. The mechanical properties of the membranes were followed by a tension test and dynamic mechanical analysis (DMA), with the sample in wet conditions after being immersed in varying compositions of water/ethanol mixtures. Results show that with the increasing of water content, the Young's and storage modulus decrease systematically. For water contents of ca. 35 vol%, chitosan (CHT) exhibits a glass transition, showing an elastomeric plateau in the elastic modulus above this hydration level and the occurrence of a peak in the loss factor. Due to the semi-crystalline nature of CHT, membranes of this biomaterial present a shape memory capability induced by water uptake. By fixation of the permanent shape by further covalent cross-linking, the membranes can have different permanent shapes appropriate for different applications, including in the biomedical area.

Cell-Adhesive Bioinspired and Catechol-Based Multilayer Freestanding Membranes for Bone Tissue Engineering

“…Chitosan with a N -deacetylation degree of 80% and a molecular weight in the range of 190–310 kDa, HA as hyaluronic acid sodium salt from Streptococcus equi with a molecular weight in the range of 1500–1800 kDa, DN as dopamine hydrochloride with a molecular weight of 189.64 g mol −1 and N -(3-dimethylaminopropyl)- N ′-ethylcarbodiimide hydrochloride (EDC) (purum ≥ 98.0% (AT)) were purchased from Sigma (St. Louis, MO, USA). These materials were used as received, except CHT, which was purified afterwards, following a standard procedure reported elsewhere [39].…”

Shape‐Memory Polymers for Biomedical Applications

“…[10] Other groups have also exploited the UPy crosslinking strategy using different polymer backbones such as poly(vinyl alcohol), for which excellent shape recovery ratios of 99% were obtained, [136] or UPy-functionalized (meth)acrylate monomers, exploited to obtain a triple shape-memory polymer. [137] In addition to gelatin, [10] other biopolymers have also been reported to exhibit shape-memory effect that can be triggered by means of hydration including chitosan, [1,2,[138][139][140] cellulose, [138,[141][142][143] starch, [19,144] collagen, [145] and keratin. [146,147] The practical applications of bio-based shape-memory polymers that can be triggered by hydration become evident in applications such as self-expanding stents as reported by Chen et al [1] Their chitosan-based stent is able to expand rapidly (150 s), allowing for a minimally invasive insertion of the stent.…”

“…In addition to gelatin, [ 10 ] other biopolymers have also been reported to exhibit shape‐memory effect that can be triggered by means of hydration including chitosan, [ 1,2,138–140 ] cellulose, [ 138,141–143 ] starch, [ 19,144 ] collagen, [ 145 ] and keratin. [ 146,147 ] The practical applications of bio‐based shape‐memory polymers that can be triggered by hydration become evident in applications such as self‐expanding stents as reported by Chen et al [ 1 ] Their chitosan‐based stent is able to expand rapidly (150 s), allowing for a minimally invasive insertion of the stent.…”

“…To date, direct triggers reported in literature mainly include temperature and light. However, indirect triggers such as exposure to a solvent, [1,2] ultrasound, [3] and others have also been reported. [4][5][6][7] Over the past few decades, shape-memory materials have gained increasing attention in biomedical research.…”

“…To date, direct triggers reported in literature mainly include temperature and light. However, indirect triggers such as exposure to a solvent, [ 1,2 ] ultrasound, [ 3 ] and others have also been reported. [ 4–7 ]…”