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Xylan Based Composite Nanoparticles and Biofoams for Drug Delivery and Tissue Engineering
(01. Izmir Institute of Technology, 2022) Zeybek, Nüket; Büyükkileci, Ali Oğuz
Xylan is a hemicellulosic polysaccharide, which can be obtained from forest and agricultural wastes. Similar to some other polysaccharides, xylan can find application in drug delivery and tissue engineering due to its availability, structural diversity, biocompatibility, biodegradability, and low cost. In the first part of the study, xylan-based nanoparticles were developed for colontargeted oral drug delivery. Xylan is resistant to digestion and absorption in the upper GIT and is degraded by hydrolysis of glycosidic bonds by the colon microbiota; this makes it prominent in targeted drug delivery to the colon. The drug carrier was combined with a polymeric micelles system to increase the bioavailability of hydrophobic bioactive molecules in the colon targeting. The model hydrophobic molecule, curcumin, was loaded in the core of the triblock copolymer P-123 micelles by the thin-film hydration method. Curcumin-loaded micelles were coated with xylan supported by chitosan and tripolyphosphate using the ionic gelation method. In another approach, xylan was also used to coat curcumin-loaded mesoporous silica nanoparticles to prevent premature drug release in the upper GIT in colon-targeted delivery. In both approaches, the drugcontaining structures were maintained up to the colon and the drug was released upon bacterial hydrolysis of xylan. In the second part, xylan-based biofoams were synthesized by the oil in water emulsion templated method. Several physicochemical and mechanical tests have shown that at the optimal conditions foams with promising properties could be synthesized. Besides, to develop a more effective tissue therapy by utilizing the synergistic effect of the drug delivery and scaffold system, a model drug was successfully loaded into biofoams. This study showed that xylan is a promising feedstock for the synthesis of stable and biocompatible materials in biomedical applications, which reveals its potential capability in drug carriers and scaffolds.
Development of Chitosan Based Biofoams
(Izmir Institute of Technology, 2020) Olcay Kurt, Aybike Nil; Polat, Mehmet; Polat, Hürriyet; Polat, Mehmet; Polat, Hürriyet
Chitosan is a preferred bio-foam material used in many research fields such as tissue engineering and drug delivery due to its unique structural features (wide pH stability, nontoxic-biocompatible-biodegradable, anti-inflammatory, antimicrobial). However, chitosan foams are mechanically too weak to maintain the desired shape until newly formed tissue natures. A wound infection and serious tissue necrosis, endanger human's lives. So, a dressing is required to protect loss of fluids and proteins from the wound area and prevents any bacterial invasion replacing the function of skin temporarily. Therefore controlled drug release from a wound dressing is necessary with a biocompatibility and enough mechanical strength. The aim of this study was the synthesis of mechanically durable - dual porosity chitosan bio-foams to provide a controlled drug release. For this purpose, oil droplets formed in a chitosan solution were used as templates to produce micropores that also contain vancomycin (a model antibiotic-hydrophylic) and curcumin (a model anti-inflammatory-hydrophobic) in the walls of the chitosan matrix with large structural voids. An anionic surfactant, sodium dodecyl sulfate (SDS) alone, was used as a crosslinking agent which was a new approach. Then the structures were characterized by SEM, FTIR, mechanical tests and BET analysis. The chitosan foams have dual pore structures. 1) The intrinsic micro pores that the walls of chitosan matrix have with different morphology that depends on the oil phase. 2) The structural voids that the chitosan matrix have, present even in the absence of an oil phase that depends on the experimental conditions. The mechanical strength of the foams were found to be much higher (up to 250 kPa) compare to the foams produced in literature and suggested to be suitable to use for wound dressing applications. The drug release mechanism of foams were found to depend on the conditions used for foam development and the released kinetics were presented with a mathematical model.

Phd Degree / Doktora

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