The role of hydrogels with tethered acetylcholine functionality on the adhesion and viability of hippocampal neurons and glial cells

Abstract

In neural tissue engineering, designing materials with the right chemical cues is crucial in providing a permissive microenvironment to encourage and guide neuronal cell attachment and differentiation. Modifying synthetic hydrogels with biologically active molecules has become an increasingly important route in this field to provide a successful biomaterial and cell interaction. This study presents a strategy of using the monomer 2-methacryloxyethyl trimethylammonium chloride (MAETAC) to provide tethered neurotransmitter acetylcholine-like functionality with a complete 2-acetoxy-N,N,N-trimethylethanaminium segment, thereby modifying the properties of commonly used, non-adhesive PEG-based hydrogels. The effect of the functional monomer concentration on the physical properties of the hydrogels was systematically studied, and the resulting hydrogels were also evaluated for mice hippocampal neural cell attachment and growth. Results from this study showed that MAETAC in the hydrogels promotes neuronal cell attachment and differentiation in a concentration-dependent manner, different proportions of MAETAC monomer in the reaction mixture produce hydrogels with different porous structures, swollen states, and mechanical strengths. Growth of mice hippocampal cells cultured on the hydrogels showed differences in number, length of processes and exhibited different survival rates. Our results indicate that chemical composition of the biomaterials is a key factor in neural cell attachment and growth, and integration of the appropriate amount of tethered neurotransmitter functionalities can be a simple and effective way to optimize existing biomaterials for neuronal tissue engineering applications.

Biomimetic Polymer Brushes Containing Tethered Acetylcholine Analogs for Protein and Hippocampal Neuronal Cell Patterning

“…13,18 Moreover, polymer brushes with different amounts of MAETAC have been prepared (40%, 30%, 20%, and 10%) and tested in the initial studies (data not shown), and samples with 10% MAETAC showed the best results in neuronal cell culture experiments. The reaction was carried out in two steps (Figure 1A).…”

Dynamic Manipulation of Hydrogels to Control Cell Behavior: A Review

“…Until recently, biomaterial designs generally focused on homogeneous and static incorporation of biochemical moieties, 17 such as cell adhesion peptides, 8,18 growth factors, 19,20 cytokines, 21 and neurotransmitters. 22,23 Biomaterial designs were commonly based on the presentation of uniform mechanical properties within the biomaterial scaffolds. 24 Static micro-and nanofabricated topographies have also been introduced into scaffolds to influence cell morphology, alignment, adhesion, migration, proliferation, and cytoskeleton organization.…”

Silk–tropoelastin protein films for nerve guidance

“…As the content increased there was a subsequent decrease in neurite extension; at very high charge density. Increases in neuron adhesion and viability until a critical positive charge concentration was also reported for mice hippocampal cells on PEG-based hydrogels modified with positively-charged acetycholine functional groups (47). The decrease in neurite extension in synthetic hydrogel systems at high charge content may be attributed to increased concentrations of trimethylammonium chloride groups, which may be less biocompatible than the protein-based materials in silk-tropoelastin films.…”