Development of chitosan-tripolyphosphate fibers through pH dependent ionotropic gelation
ABSTRACT Incorporation of phosphate groups into a material may be of particular interest as they act as templates for hydroxyapatite growth through complexation with Ca(2+) and thus improve the osteoconduction property. The phosphate groups can be incorporated into chitosan through ionotropic gelation with tripolyphosphate (TPP). Interestingly, the ion pairs formed through negatively charged phosphate groups with protonated amine functionality of chitosan in ionotropic gelation are expected to provide chitosan with an amphoteric character, which may facilitate protein adhesion following enhanced attachment of anchorage dependant cells than chitosan, which shows poor cell adhesion properties. In this study, chitosan-tripolyphosphate (TPP) fibers with varying phosphate contents were prepared through wet spinning in STPP baths of different pH. Gelation kinetics and gel strength of chitosan with STPP solutions of three different pH were evaluated and compared with that of NaOH solution for evaluation of their influence on nature of gelation. The solution pH of STPP baths was found to have significant control on the extent of ionic cross-linking and physico-chemical properties of the fibers. Moreover, this kinetically driven ionotropic gelation of chitosan by TPP results in low degree of crystallinity of chitosan-TPP fibers and consequently their lower thermal stability than chitosan fibers.
SourceAvailable from: Pasquale Sacco[Show abstract] [Hide abstract]
ABSTRACT: Polysaccharide networks, in the form of hydrogels and dried membranes based on chitosan and on the cross-linker tripolyphosphate (TPP) were developed using a novel approach. TPP was incorporated into chitosan by slow diffusion to favor a controlled gelation. By varying chitosan, TPP and NaCl concentration, transition from inhomogeneous to homogeneous systems was achieved. Rheology and uniaxial compression tests enabled to identify the best performing hydrogel composition with respect to mechanical properties. FTIR, 31P NMR and spectrophotometric methods were used to investigate the interaction chitosan-TPP, the kinetics of phosphates diffusion during the dialysis and the amount of TPP in the hydrogel. A freeze-drying procedure enabled the preparation of soft pliable membranes. The lactate dehydrogenase assay demonstrated the biocompatibility of the membranes towards fibroblasts. Overall, we devised a novel approach to prepare homogeneous macroscopic chitosan/TPP-based biomaterials with tunable mechanical properties and good biocompatibility that show good potential as novel polysaccharide derivatives.Biomacromolecules 08/2014; 15(9). DOI:10.1021/bm500909n · 5.79 Impact Factor
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ABSTRACT: Chitosan films were prepared in combination with sodium tripolyphosphate (TPP) cross-linking and were investigated on the prevention for trans-contamination and preservation of egg quality. The study demonstrated that chitosan films significantly decrease Salmonella enteritidis settlement (from 7% to 0.5%) and penetration of eggshells (from 93 to 58% of penetrated eggs). Due to neither bactericidal action nor bacteriostatic effect of films was observed by the enumeration method, films seem to act as a physical barrier. Moreover, results showed potential applications of coating with properties to preserve the internal quality of eggs: the weight loss is not significantly affected (weight loss remains 4% average after 23 days) and the Haugh unit is significantly higher (26 and 37 were evaluated for eggs uncoated and coated, respectively) in the presence of chitosan film.International Journal of Food Science & Technology 11/2014; 50(3). DOI:10.1111/ijfs.12690 · 1.35 Impact Factor
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ABSTRACT: Cancer nanotheranostic materials are useful in real-time monitoring of drug delivery and therapeutic action against tumor cells as they co-deliver therapeutic and imaging functions. In this study, we report the use of natural fluorescent protein (R-Phycoerythrin (PE)) in the preparation of novel multifunctional Chitosan-Silver-Phycoerythrin Nanocomposites (CS-Ag-PE NCs) and the theranostic potentials of the synthesized nanocomposites (NCs) were evaluated against Triple negative breast cancer (MDA-MB-231) cells. Absorption behavior of the synthesized CS-Ag NCs and CS-Ag-PE NCs at different pH was studied by UV-Vis and FT-IR spectroscopy for determining the interaction of silver with Chitosan and CS-Ag NCs with PE. Morphological features of CS-Ag NCs and CS-Ag-PE NCs and cellular uptake of CS-Ag-PE NCs were evaluated by TEM. Flow cytometry analyses were performed to determine the conjugation efficiency of CS-Ag-NCs to PE, stability of the CS-Ag-PE NCs and cellular localization of NCs at dose-dependent concentrations. Further, we substantiated the effect of CS-Ag-PE NCs in the activation of ROS mediated caspase-dependent intrinsic apoptosis by analyzing of expression of apoptotic proteins and bcl-2 family genes, respectively. The ionic interaction between PE and CS-Ag NCs resulted in a stable theranostic fluorescent NC complex that enabled the real time probing of delivery, distribution and therapeutic functions of NCs in cancer cells. The theranostic NCs of this study exhibited apoptotic induction potential in cancer cells but low toxicity in normal breast cells.RSC Advances 01/2015; 5(16). DOI:10.1039/C4RA14043E · 3.71 Impact Factor