Thermo-sensitive chitosan–cellulose derivative hydrogels: swelling behaviour and morphologic studies

Abstract

Hydrogels are three-dimensional, hydrophilic, polymer networks that are able to imbibe large amounts of water or biological fluids, while maintaining their dimensional stability. The polymer binding might be achieved by chemical or physical interactions. Physical crosslinking of a polymer to form its hydrogel, might be accomplished either by casting-solvent evaporation (SC) method or by freeze-thaw (FT) technique. The physical hydrogels, especially the ones based on natural biopolymers, like polysaccharides, are being widely used in industry and medicine due to their favourable properties: biocompatibility; biodegradability; low toxicity and eco-friendly characteristics. Polysaccharides, like chitosan (CH) and (hydroxypropyl)methyl cellulose (HPMC) have gained great attention due to its stimuli sensitive properties: pH and temperature responsiveness, respectively. Thus, within this work we have developed physically crosslinked CH:HPMC hydrogel films, using both SC and FT techniques. The attained CH:HPMC membranes were evaluated in terms of their swelling, thermal (low critical solution temperature-LCST), structural (attenuated total reflectance Fourier transform infrared spectroscopy) and morphological (scanning electron microscopy and atomic force microscopy) properties. According to these results, the developed membranes exhibit a good miscibility between the two component biopolymers. Moreover, the CH:HPMC membranes exhibit a high swelling capacity (SW FT = 1,172 and SW SC = 7,323), a low surface roughness (Sq = 5.6-9.5 nm) and an elevated LCST (LCST = 85.2-87.5°C). The stimuli sensitive behaviour makes hydrogels appealing for the design of smart devices applicable in a variety of technological fields. In our particular case, we envisage the application of such materials as active substances (moisturisers, antiperspirants and scents) delivers, into textile substrates in a controlled manner.

Chitosan temperature‑sensitive gel loaded with drug microspheres has excellent effectiveness, biocompatibility and safety as an ophthalmic drug delivery system

“…Traditional eye drops are usually lost from the ocular surface by tear washing or nasolacrimal drainage immediately after administration, with poor ocular bioavailability and numerous adverse reactions (2). In addition, due to the inconvenience of night administration, the pharmacological peak-valley phenomenon is prominent, greatly affecting the treatment effect of ocular drugs.…”

Smart Hydrogel for the pH‐Selective Drug Delivery of Antimicrobial Compounds

“…Moreover, hydrogels’ drug delivery ability is directed related with their swelling capacity . Swelling profile is imposed by the crosslinking degree, molecules hydrophilicity and ionic strength . The HPMC‐CS hydrogel dissolved, as soon as, it was immersed in water, because of it poor crosslinking degree as mention before and making impossible it characterization regarding swelling and drug delivery properties.…”

“…In the present work, we add chitosan (CS), a cationic polysaccharide, to grant pH‐sensitive swelling and drug delivery to the cyclodextrin‐cellulose based hydrogel. CS hydrogels networks show a typical pH‐sensitive swelling, being swollen in acidic medium, due to the protonated amine groups repulsion and shrunk in neutral and alkaline medium, influenced by the unprotonated amine groups …”

Biopolymer Electrolyte Membranes (BioPEMs) for Sustainable Primary Redox Batteries

“…[6] Moreover, with the growing commercialization of PEMFCs, the disposal of a large number of used Nafion membranes will become an important environmental issue. [17][18][19][20][21][22][23] In particular, chitosan (CH) and its derivatives are been extensively investigated as some of the most attractive "green" materials for power sources applications due to their biodegradability, biocompatibility, nontoxicity, and low-cost. [7][8][9][10] Recently, the aim to develop bio-solid polymer electrolytes (BioSPEs) based on natural polymers has arisen as alternative candidates to substitute synthetic polymer-based membranes due to their abundance, low-cost, and environmentally friendly nature.…”

“…[7][8][9][10] Recently, the aim to develop bio-solid polymer electrolytes (BioSPEs) based on natural polymers has arisen as alternative candidates to substitute synthetic polymer-based membranes due to their abundance, low-cost, and environmentally friendly nature. [17,23] One of The proliferation of portable electronic devices has resulted in an increase of e-waste that is generated after their use. [17][18][19][20][21][22][23] In particular, chitosan (CH) and its derivatives are been extensively investigated as some of the most attractive "green" materials for power sources applications due to their biodegradability, biocompatibility, nontoxicity, and low-cost.…”