Biomimetic hydrogel based on HET-s amylo\"id fibers for long-term culture of primary hippocampal neurons

TL;DR

This study demonstrates that HET-s amyloid fiber hydrogels are a versatile, non-toxic coating capable of supporting primary hippocampal neuron cultures for over 45 days, with potential for in vivo applications.

Contribution

We introduce HET-s amyloid fiber hydrogels as a novel, biocompatible coating for long-term neuronal culture and potential in vivo use, highlighting their unique properties and interactions.

Findings

Neurons cultured on HET-s hydrogels survive over 45 days.

Neurons exhibit spontaneous network activity on these hydrogels.

Dendrites can penetrate the hydrogel, enabling recordings.

Abstract

Historically, amyloid fibers (AF) in research has always been linked to degenerative diseases. However, HET-s AF, by their morphology and function, have only little in common to pathogenic amyloid fibers such as {\alpha}-synuclein or a\b{eta} and they have appeared as promising candidate for biocoating since few years. Here we have shown than HET-s amyloid fibers hydrogel is an extremely polyvalent coating material for the in vitro culture of primary hippocampal neurons. First, the non-cytotoxicity was demonstrated in vitro using standardized ISO protocols. Then, it is shown that in vitro culture of primary hippocampal neurons on HET-s AF hydrogels could last more than 45 days with clear signatures of spontaneous network activity, with which is a feat that not many other coatings have achieved yet. Finally, interactions between the cells, the dendrites and the hydrogels are highlighted, showing that dendrites might be able to penetrate the hydrogels in depth, therefore allowing recordings even within micrometer-thick hydrogels. In the end, those properties combined with group functionalization using standard biochemistry techniques, makes HET-s hydrogels ideal candidates to be used for the long-term growth of neurons as well as other types of cells. This versatility and easiness to use are definitely still unheard, especially for protein material. Due to its ability to transform from dry films to hydrogel when in contact with the extracellular matrix (ECM), it could also be used for in vivo implants, solving the issue of hydrogel damaging during the implant surgery.