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Polymers 2018, 10(12), 1317;

Smart Shear-Thinning Hydrogels as Injectable Drug Delivery Systems

Laboratory for Innovations in Microengineering (LiME), Department of Mechanical Engineering, University of Victoria, Victoria, BC V8P 5C2, Canada
Center for Biomedical Research, University of Victoria, Victoria, BC V8P 5C2, Canada
Center for Advanced Materials and Related Technologies, University of Victoria, Victoria, BC V8P 5C2, Canada
Department of Informatics, Bioengineering, Robotics, and System Engineering, University of Genoa, Genoa 16145, Italy
Author to whom correspondence should be addressed.
Received: 30 October 2018 / Revised: 22 November 2018 / Accepted: 22 November 2018 / Published: 28 November 2018
(This article belongs to the Special Issue Smart and Functional Elastomers, Hydrogels, and Ionogels)
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In this study, we fabricated and characterized a smart shear-thinning hydrogel composed of gelatin and laponite for localized drug delivery. We added chitosan (Chi) and poly N-isopropylacrylamide-co-Acrylic acid (PNIPAM) particles to the shear-thinning gel to render it pH-responsive. The effects of total solid weight and the percentage of laponite in a solid mass on the rheological behavior and mechanical properties were investigated to obtain the optimum formulation. The nanocomposite gel and particles were characterized using Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), zeta potential, and dynamic light scattering techniques. Finally, release related experiment including degradability, swelling and Rhodamine B (Rd) release at various pH were performed. The results suggest that incorporation of silicate nanoplatelets in the gelatin led to the formation of the tunable porous composite, with a microstructure that was affected by introducing particles. Besides, the optimum formulation possessed shear-thinning properties with modified rheological and mechanical properties which preserved its mechanical properties while incubated in physiological conditions. The release related experiments showed that the shear-thinning materials offer pH-sensitive behavior so that the highest swelling ratio, degradation rate, and Rd release were obtained at pH 9.18. Therefore, this nanocomposite gel can be potentially used to develop pH-sensitive systems. View Full-Text
Keywords: shear-thinning; hydrogels; pH-responsive; gelatin; laponite; chitosan; N-isopropylacrylamide; nanocomposite shear-thinning; hydrogels; pH-responsive; gelatin; laponite; chitosan; N-isopropylacrylamide; nanocomposite

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Samimi Gharaie, S.; Dabiri, S.M.H.; Akbari, M. Smart Shear-Thinning Hydrogels as Injectable Drug Delivery Systems. Polymers 2018, 10, 1317.

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