Usage of natural chitosan membrane obtained from insect corneal lenses as a drug carrier and its potential for point of care tests.

Chitosan is an indispensable biopolymer for use as a drug carrier thanks to its non-toxic, biodegradable, biocompatible, antimicrobial, and anti-oxidative nature. In previous studies, chitosan was first dissolved into weak acids and formed into gel, then used for carrying pharmaceutically active compounds such as nanoparticles, capsules, composites, and films. Using the produced chitosan gel after dissolving it in weak acids has advantages, such as ease of processing for loading the required amount of active substance and making the desired shape and size. However, dissolved chitosan loses some of its natural properties such as fibrous structure, crystallinity, and thermal stability. In this study, for the first time, three-dimensional chitosan lenses obtained from an insect's (Tabanus bovinus) compound eyes, with the original shape intact, were tested as a drug carrier. A model drug, quercetin, was loaded into chitosan membrane, and its release profile was examined. Also, a point-of-care test was conducted for both chitin and chitosan membranes. Chitin and chitosan membranes obtained from insect corneal lenses were characterized by using FTIR, TGA, elemental analysis, and surface wettability analysis as well as stereo, binocular, and scanning electron microscopies. It was observed that chitosan membrane could be used as a drug carrier material. Both chitin and chitosan membranes will be improved for lateral flow assay, and these membranes can be tested for other bioengineering applications in further studies.

An inclusive physicochemical comparison of natural and synthetic chitin films.

Natural and synthetic chitin films, obtained from the same source were produced and their physicochemical properties were examined comparatively. Firstly, natural chitin film was obtained from elytra of an insect (Oryctes nasicornis L.) and purity of the obtained chitin film (degree of acetylation: 79±2%) was demonstrated by solid state 13C nuclear magnetic resonance (13C NMR). Then, the synthetic film was produced by dissolving of natural chitin film in LiCl-DMAc. The obtained natural and synthetic films were characterized by AFM, TGA, DSC, FTIR, mechanical properties, light transmission and contact angle. The analyses result demonstrated that natural chitin film lost very important properties such as high thermal stability, transparency, nanofibrous nature, tensile strength, Young's modulus and hydrophobicity after transforming the synthetic film.

Three-dimensional chitin rings from body segments of a pet diplopod species: Characterization and protein interaction studies.

Physicochemical characterization of new chitin isolates can provide valuable insights into designing of biomimetic materials. Chitin isolates with a definite three-dimensional (3D) structure can exhibit characteristics that distinguish them from other chitin specimens that are in form of powder or flakes without a definite and uniform shape. Herein, 3D chitin rings were produced from body segments of a diplopod (Archispirostreptus gigas) inhabiting tropical regions. This organism is cultured easily and can reach 38cm in length, which makes it a suitable source for isolation of chitin. The chitin rings were characterized via TGA, FT-IR, SEM and XRD analyses. Enzymatic digestion test with chitinase demonstrated that chitin isolates had high purity (digestion rate: 97.4%). The source organism had high chitin content; 21.02±2.23% on dry weight. Interactions of the chitin rings with bovine serum albumin (BSA) protein were studied under different conditions (pH: 4.0-8.0, chitin amount: 6-14mg, contact time: 30-360min, protein concentration: 0.2-1mg/mL). The highest BSA adsorption was observed at pH5.0 at 20°C. The adsorption equilibrium data exhibited a better fit to Langmuir adsorption and the pseudo-first order kinetic models. The findings presented here can be useful for further studies aiming to develop biocompatible and nontoxic biomaterials.