Biology subjects

Braschler, T.

Publications and source records attributed to Braschler, T..

3 recordsLinked to original sources

bioRxiv2020

An injectable meta-biomaterial

We present a novel type of injectable biomaterial with an elastic softening transition. The material enables in-vivo shaping, followed by induction of 3D stable vascularized tissue adopting the desired shape. We establish the necessary geometrical and physical parameters by extensive numerical simulation. Irregular particle shape dramatically enhances yield strain for in-vivo stability against deformation, while friction and porosity provide the elastic softening transition as an emergent meta-material property. Accordingly, we synthesize our injectable meta-biomaterial as a suspension of irregularly fragmented, highly porous sponge-like microgels. The meta-biomaterial exhibits both high yield strain, and the desired novel elastic softening transition for in-situ shaping and unprecedented dynamic matching of adipose tissue mechanics. In vivo, predetermined shapes can be sculpted manually after subcutaneous injection in mice. The 3D shape is maintained during excellent host tissue integration into the particle pore space. The meta-biomaterial sustains vascularized connective tissue to the end of one-year follow-up.

bioengineering↗

bioRxiv2020

Neurothreads: Cryogel carrier-based differentiation and delivery of mature neurons in the treatment of Parkinson's disease

We present in-vivo transplantation of mature dopaminergic neurons by means of macroporous, injectable carriers, to enhance cell therapy in Parkinsons disease. The carriers are synthesized by crosslinking carboxymethylcellulose at subzero temperatures, resulting in cylindrical, highly resilient porous cryogels, which we term Neurothreads. We develop efficient covalent immobilization of the neural adhesion proteins laminin 111, collagen IV and fibronectin, as well as of the extracellular matrix extract Matrigel to the Neurothreads. We observe the highest neural spreading on laminin 111 and Matrigel. We show compatibility with established dopaminergic differentiation of both HS420 human embryonic stem cells and the LUHMES midbrain model cell line. The porous Neurothread carriers withstand compression during minimally invasive stereotactic injection, and ensure viability of mature neurons including extended neurites. Implanted into the striatum in mice, the Neurothreads enable survival of transplanted mature neurons obtained by directed differentiation of the HS420 human embryonic stem cells, as a dense tissue in situ, including dopaminergic cells. With the successful in-vivo transfer of intact, mature and fully open 3D neural networks, we provide a powerful tool to extend established differentiation protocols to higher maturity and to enhance preconfigured neural network transplantation.

bioengineering↗

bioRxiv2020

Highly efficient cardiac differentiation and maintenance by thrombin-coagulated fibrin hydrogels enriched with decellularized porcine heart extracellular matrix

We provide a blend of cardiac decellularized extracellular matrix (dECM) from porcine ventricular tissue and fibrinogen for the formation of an in-vitro 3D cardiac cell culture model. Rapid and specific coagulation with thrombin allows gentle inclusion of cells while avoiding sedimentation during formation of the dECM-fibrin composite. We use the system in co-culture with Nor-10 fibroblasts to enhance cardiogenic differentiation of the H9c2 myoblast cell line. The combination of co-culture and appropriate substrate allows to abrogate the use of retinoids, classically considered necessary for cardiogenic H9c2 differentiation. Further enhancement of differentiation efficiency is obtained by 3D embedding. We then proceed with culture of rat neonatal cardiomyocytes in the 3D system. While for H9c2 cells, the collagen content of the dECM was the key factor required for efficient differentiation, the use of dECM-fibrin has specific advantages regarding the culture of neonatal cardiomyocytes. Calcium imaging and analysis of beating motion both indicate that the dECM-fibrin composite significantly enhances recovery, frequency, synchrony and maintenance of spontaneous beating, as compared to various controls including matrigel, pure fibrin and collagen I, but also a fibrin-collagen I blend.

bioengineering↗