Injectable conductive collagen/alginate/polypyrrole hydrogels as a biocompatible system for biomedical applications

Abstract

Recently, Injectable Conducting Hydrogel (ICH) systems have gained much attention for tissue engineering and regenerative medicine. These systems can promote the regeneration of tissues responding to electrical responses. In this study, a novel ICH system was introduced. To achieve this system, firstly, a soluble non-toxic polypyrrole (PPy) synthesized by grafting pyrrole on alginate (Alg) backbone (Alg-graft-PPy), and then, ICH systems were prepared by the given ratios of Alg-graft-PPy, Alg, and collagen (Col). Three different amounts of Col (0.5, 1, and 1.5 mg/ml) were added to the system including Alg-graft-PPy: Alg wt. % with the ratios of 20:80 and 30:70. FTIR spectroscopy, electrical conductivity, viscosity, syringeability, gelation time, and MTT assay were performed in order to characterize the produced hydrogels. Due to the rheological behavior of 20:80 (Alg-graft-PPy: Alg wt. %), it was recognized more suitable to inject. Also this system associated with 0.5 mg/ml Col introduced as the best sample with respect to its viscosity and injectability. This ICH system has shown high conductivity in addition to a good level of cell viability and syringeability. With respect to properties of the produced ICH system, it can be applied for bone, nerve, muscle and cardiac cells, which respond to electrical impulses.

Simultaneous release of melatonin and methylprednisolone from an injectable in situ self‐crosslinked hydrogel/microparticle system for cartilage tissue engineering

“…In this method, a constant force was applied at a preload of 0.1 N and a test speed of 5 mm/min on the piston of a 2.5 mL syringe with a double syringe including the two‐part containers and 21G needle similar to other studies . The injectability value was defined as the average time needed to expel 1 mL of hydrogel …”

Rational design of microfabricated electroconductive hydrogels for biomedical applications

“…PPy is an electroconductive polymer that has been used for the synthesis of ECHs due to its facile synthesis, environmental stability, tunable mechanical properties, and biocompatibility [109][110][111]. PPy has also been used for other purposes, including drug delivery systems [78,112] and bio-electrodes [113,114], as well as the engineering of cardiac tissue constructs [115,116] and artificial muscles [117].…”

Synthesis and 3D Printing of Conducting Alginate–Polypyrrole Ionomers

“…Often, a small molar ratio of a polyanion serves as templates to control the morphology of the resulting material, while the bulk of the charge balancing is due to the fact of other anions. In other cases, biopolymers in the form of hydrogels simply form a matrix or template, within which conventional ICP polymers can be grown or deposited [17][18][19]. For example, recent reports have described the formation of cross-linked alginate hydrogels in which PPy or PANI have been electrochemically deposited.…”