Biology subjects

Trichet, L.

Publications and source records attributed to Trichet, L..

7 recordsLinked to original sources

bioRxiv2026

Collagen-based bilayered biomimetic tubular materials for vascular and airway applications

Biomimetic tubular scaffolds hold great promise for tackling unmet clinical needs thanks to their biocompatibility and recapitulation of cellular microenvironments, conferring the ability to promote regeneration. Potential applications include small-diameter vascular implants and grafts for airway repair, for which no viable off-the-shelf solutions currently exist. The tubular materials (4 and 8 mm internal and external diameters) presented here consist purely of type I collagen, contain no chemical crosslinkers, and reproduce the multi-scale architecture of the native tissue including the presence of collagen fibrils. A novel two-step protocol provides materials with distinct concentric layers. A porous external structure, obtained by means of ice templating combined with collagen topotactic fibrillogenesis, favours oriented cell colonization. A smooth and much less porous internal layer provides mechanical and water-tightness properties relevant for in vivo implantation and promotes the formation of an endothelial monolayer under both static and flow conditions. The compliance of the double-layered materials under physiological pressure is close to that of piglet carotid arteries. The materials are also determined to be sufficiently flexible to provide the ability to perform ex vivo anastomosis with bronchi, although the relatively low value of suture retention strength remains a limitation for in vivo suturing.

bioengineering↗

bioRxiv2024

State diagrams of type I collagen for the rational design of biomimetic materials

Ideally, designing tissue engineering grafts and 3D cell culture materials should rely on mimicking the architecture and composition of the extracellular matrix, which is predominantly comprised of type I collagen. However, while collagen molecules are assembled into fibrils by cells in vivo, well-organized fibrils rarely form spontaneously in vitro. Indeed, the physico-chemical conditions for fibrillogenesis are still poorly understood and their influence on the formation and properties of fibrillar biomimetic materials remains elusive. Here, we establish state diagrams for type I collagen over an unprecedented range of concentration and temperature, showing the collagen denaturation limits, the emergence of fibrils in acidic conditions, and a new regime of collagen molecule/fibril coexistence. We also show how the state diagrams can be used to understand the formation of biomimetic materials by classical methods, as illustrated here by collagen freeze-casting. Therefore, these state diagrams will help to optimize the production of collagen-based biomimetic materials.

bioengineering↗

bioRxiv2023

Tunable biomimetic materials elaborated by ice templating and self-assembly of collagen for tubular tissue engineering

Synthetic tubular grafts currently used in clinical context fail frequently, and the expectations that biomimetic materials could tackle these limitations are high. However, developing tubular materials presenting structural, compositional and functional properties close to those of native tissues remains an unmet challenge. Here we describe a combination of ice templating and topotactic fibrillogenesis of type I collagen, the main component of tissues extracellular matrix, yielding highly concentrated yet porous tubular collagen materials with controlled hierarchical architecture at multiple length scales, the hallmark of native tissues organization. By modulating the thermal conductivity of the cylindrical molds, we tune the macroscopic porosity defined by ice. Coupling the aforementioned porosity patterns with two different fibrillogenesis routes results in a new family of materials whose textural features and the supramolecular arrangement of type I collagen are achieved. The resulting materials present hierarchical elastic properties and are successfully colonized by human endothelial cells and alveolar epithelial cells on the luminal side, and by human mesenchymal stem cells on the external side. The results reported here demonstrate the relevance of the proposed straightforward protocol, likely to be adapted for larger graft sizes, to address ever-growing clinical needs such as peripheral arterial disease or tracheal and bronchial reconstructions.

bioengineering↗

bioRxiv2022

Porous yet Dense matrices: using ice to shape collagen 3D cell culture systems with increased physiological relevance

Standard in vitro cell culture is one of the pillars of biomedical science. However, there is increasing evidence that 2D systems provide biological responses that are often in disagreement with in vivo observations, partially due to limitations in reproducing the native cellular microenvironment. 3D materials that are able to mimic the native cellular microenvironment to a greater extent tackle these limitations. Here, we report Porous yet Dense (PyD) type I collagen materials obtained by ice-templating followed by topotactic fibrillogenesis. These materials combine extensive macroporosity, favouring the cell migration and nutrients exchange, as well as dense collagen walls, which mimic locally the Extracellular Matrix. When seeded with Normal Human Dermal Fibroblasts (NHDFs), PyD matrices allow for a faster and more extensive colonisation when compared with equivalent Non-Porous matrices. The textural properties of the PyD materials also impact cytoskeletal and nuclear 3D morphometric parameters. Due to the effectiveness in creating a biomimetic 3D environment for NHDFs and the ability to promote cell culture for more than 28 days without subculture, we anticipate that PyD materials could configure an important step towards in vitro systems applicable to other cell types and with higher physiological relevance.

bioengineering↗

bioRxiv2021

Bioengineering a Miniaturized In Vitro 3D Myotube Contraction Monitoring Chip For Modelization of Muscular Dystrophies

Quantification of skeletal muscle functional contraction is essential to assess the outcomes of therapeutic procedures for muscular disorders. Muscle three-dimensional "Organ-on-chip" models usually require a substantial amount of biological material, which is problematic in the context of limited patient sample. Here we developed a miniaturized 3D myotube culture chip with contraction monitoring capacity. Optimized micropatterned substrate design enabled to obtain high culture yields in tightly controlled microenvironments. Spontaneous contractions in myotubes derived from primary human myoblasts were observed. Analysis of nuclear morphology confirmed a similar organization between obtained myotubes and in vivo myofibers. LMNA-related Congenital Muscular Dystrophy (L-CMD) was modelled with successful development of mutant 3D myotubes displaying contractile dysfunction. This technology can thus be used to study contraction characteristics and evaluate how diseases affect muscle organization and force generation. Importantly, it requires significantly fewer starting materials than current systems, which should allow to substantially improve drug screening capability.

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↗