Biology subjects

Rieu, C.

Publications and source records attributed to Rieu, C..

3 recordsLinked to original sources

bioRxiv2021

C-STEM: ENGINEERING NICHE-LIKE MICRO-COMPARTMENTS FOR OPTIMAL AND SCALE-INDEPENDENT EXPANSION OF HUMAN PLURIPOTENT STEM CELLS IN BIOREACTORS

Human pluripotent stem cells (hPSCs) have emerged as the most promising cellular source for cell therapies. To overcome scale up limitations of classical 2D culture systems, suspension cultures have been developed to meet the need of large-scale culture in regenerative medicine. Despite constant improvements, current protocols relying on the generation of micro-carriers or cell aggregates only achieve moderate amplification performance. Here, guided by reports showing that hPSCs can self-organize in vitro into cysts reminiscent of the epiblast stage in embryo development, we developed a physio-mimetic approach for hPSC culture. We engineered stem cell niche microenvironments inside microfluidics-assisted core-shell microcapsules. We demonstrate that lumenized three-dimensional colonies maximize viability and expansion rates while maintaining pluripotency. By optimizing capsule size and culture conditions, we scale-up this method to industrial scale stirred tank bioreactors and achieve an unprecedented hPSC amplification rate of 282-fold in 6.5 days. TEASEROptimizing human pluripotent stem cells amplification by recapitulating and protecting biomimetic colonies in a bioreactor

bioengineering↗

bioRxiv2020

Thrombin-free polymerization leads to pure fibrin(ogen) materials with extended processing capacity

Fibrin is a key protein for various clinical applications such as tissue reconstruction. However, in contrast to type I collagen, fibrin shaping has so far faced major limitations related to the necessity to add thrombin enzyme to fibrinogen precursors to induce fibrin self-assembly. Here we report a thrombin-free gelation pathway of fibrinogen solutions by incubation at 37{degrees}C in mild acidic conditions. We unravel the biochemical mechanisms underlying the gelation process and draw comparison between fibrinogen and fibrin at both molecular and supramolecular levels in these conditions. The protocol enables to control the viscosity of fibrin(ogen) solutions, and to induce fibrin(ogen) gel formation by simple 37{degrees}C incubation, with a reinforcement effect at neutralization. It facilitates processing of fibrin(ogen) materials, for coating, molding and extrusion, and offers new possibilities such as 3D printing. This approach is further compatible with type I collagen processing and can provide advanced tissue engineering scaffolds with high bioactivity.

bioengineering↗

bioRxiv2020

Differential myoblast and tenoblast affinity to collagen, fibrin and mixed threads in the prospect of muscle-tendon junction modelisation

The myotendinous junction transfers forces from muscle to tendon. As such, it must hold two tissues of completely different biological and cellular compositions as well as mechanical properties (kPa-MPa to MPa-GPa) and is subject to frequent stresses of high amplitude. This region remains a weak point of the muscle-tendon unit and is involved in frequent injuries. We here produce fibrin (40 mg/mL, E0 =0.10 {+/-} 0.02 MPa) and collagen (60 mg/mL, E0=0.57 {+/-} 0.05 MPa) threads as well as mixed collagen:fibrin threads (3:2 in mass, E0 = 0.33 {+/-} 0.05 MPa) and investigate the difference of affinity between primary murine myoblasts and tenoblasts. We demonstrate a similar behavior of cells on mixed and fibrin threads with high adherence of tenoblasts and myoblasts, in comparison to collagen threads that promote high adherence and proliferation of tenoblasts but not of myoblasts. Besides, we show that myoblasts on threads differentiate but do not fuse, on the contrary to 2D control substrates, raising the question of the effect of substrate curvature on the ability of myoblasts to fuse in vitro.

bioengineering↗