<i>In‐Situ</i>Gelling Thermosensitive Hydrogels for Protein Delivery Applications

Censi, Roberta; Dubbini, Alessandra; Martino, Piera Di

doi:10.1002/9781119041412.ch4

Cited by 2 publications

(1 citation statement)

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“…In the past few years, thermosensitive biopolymer-based hydrogels that are biodegradable and biocompatible and with adjustable gel characteristics have attracted a great deal of interest because of their unlimited potential as therapeutic delivery systems and for tissue engineering as, for example, injectable depot systems. − Thermosensitive systems, especially those based on natural polymers with a lower critical solution temperature (LCST), can often be manipulated to undergo gelation near body temperature when they are introduced into the target tissue in an easily injectable way . Certain thermogelling systems are able to remain in solution at low temperature, where growth factors, cells and other biologically active elements can be incorporated, and became in situ solid at body temperature.…”

Section: Introductionmentioning

confidence: 99%

Rheological Study and Molecular Dynamics Simulation of Biopolymer Blend Thermogels of Tunable Strength

et al. 2016

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The temperature-induced gelation of chitosan/glycerophosphate (Chs/GP) systems through physical interactions has shown great potential for various biomedical applications. In the present work, hydroxyethyl cellulose (HEC) was added to the thermosensitive Chs/GP solution to improve the mechanical strength and gel properties of the incipient Chs/HEC/GP gel in comparison with the Chs/GP hydrogel at body temperature. The physical features of the macromolecular complexes formed by the synergistic interaction between chitosan and hydroxyethyl cellulose in the presence of β-glycerophosphate disodium salt solution have been studied essentially from a rheological point of view. The temperature and time sweep rheological characterizations of the thermogelling systems revealed that the sol-gel transition temperature of the Chs/HEC/GP blends is equal to 37 °C at neutral pH; with increasing HEC content in the solutions, more compact networks with considerably improved gel strength are formed without influencing the gelation time. The formed hydrogel matrix has enough mechanical integrity and adequate strength for using it as injectable in situ forming matrices for biomedical applications. The classical Winter-Chambon (W-C) and Fredrickson-Larson (F-L) theories were applied to determine the gel point. In view of the obtained results, it is shown that the F-L theory can be employed as a robust and less tedious method than the W-C approach to precisely determine the gel point in these systems. At the end, molecular simulation studies were conducted by using ab initio quantum mechanics (QM) calculations carried out on Chs and HEC models, and molecular dynamics (MD) simulations of solvated Chs/HEC blend systems showed the binding behavior of Chs/HEC polymers. Analyses of interaction energy, radial distribution function, and hydrogen bonding from simulation studies strongly supported the experimental results; they all disclosed that hydrogen-bond formation between Chs moieties with regard to HEC chains plays an important role for the stabilization of the complexes.

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