zIncubascope: Long-term quantitative imaging of multi-cellular assemblies inside an incubator.

Recent advances in bioengineering have made it possible to develop increasingly complex biological systems to recapitulate organ functions as closely as possible in vitro. Monitoring the assembly and growth of multi-cellular aggregates, micro-tissues or organoids and extracting quantitative information is a crucial but challenging task required to decipher the underlying morphogenetic mechanisms. We present here an imaging platform designed to be accommodated inside an incubator which provides high-throughput monitoring of cell assemblies over days and weeks.

Bioreactor-produced iPSCs-derived dopaminergic neuron-containing neural microtissues innervate and normalize rotational bias in a dose-dependent manner in a Parkinson rat model.

A breadth of preclinical studies now support the rationale of pluripotent stem cell-derived cell replacement therapies to alleviate motor symptoms in Parkinsonian patients. Replacement of the primary dysfunctional cell population in the disease, i.e.

Compressive stress triggers fibroblasts spreading over cancer cells to generate carcinoma in situ organization.

At the early stage of tumor progression, fibroblasts are located at the outer edges of the tumor, forming an encasing layer around it. In this work, we have developed a 3D in vitro model where fibroblasts' layout resembles the structure seen in carcinoma in situ. We use a microfluidic encapsulation technology to co-culture fibroblasts and cancer cells within hollow, permeable, and elastic alginate shells.

Engineering 3D micro-compartments for highly efficient 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 the scale-up limitations of classical 2D culture systems, suspension cultures have been developed to meet the need for large-scale culture in regenerative medicine. Despite constant improvements, current protocols that use microcarriers or generate cell aggregates only achieve moderate amplification performance.

Buckling of an Epithelium Growing under Spherical Confinement.

Many organs are formed through folding of an epithelium. This change in shape is usually attributed to tissue heterogeneities, for example, local apical contraction. In contrast, compressive stresses have been proposed to fold a homogeneous epithelium by buckling.

Role of mechanical cues and hypoxia on the growth of tumor cells in strong and weak confinement: A dual in vitro-in silico approach.

Characterization of tumor growth dynamics is of major importance for cancer understanding. By contrast with phenomenological approaches, mechanistic modeling can facilitate disclosing underlying tumor mechanisms and lead to identification of physical factors affecting proliferation and invasive behavior. Current mathematical models are often formulated at the tissue or organ scale with the scope of a direct clinical usefulness.

A model of guided cell self-organization for rapid and spontaneous formation of functional vessels.

Most achievements to engineer blood vessels are based on multiple-step manipulations such as manual sheet rolling or sequential cell seeding followed by scaffold degradation. Here, we propose a one-step strategy using a microfluidic coextrusion device to produce mature functional blood vessels. A hollow alginate hydrogel tube is internally coated with extracellular matrix to direct the self-assembly of a mixture of endothelial cells (ECs) and smooth muscle cells (SMCs).

Quantitative cell-based model predicts mechanical stress response of growing tumor spheroids over various growth conditions and cell lines.

Model simulations indicate that the response of growing cell populations on mechanical stress follows the same functional relationship and is predictable over different cell lines and growth conditions despite experimental response curves look largely different. We develop a hybrid model strategy in which cells are represented by coarse-grained individual units calibrated with a high resolution cell model and parameterized by measurable biophysical and cell-biological parameters. Cell cycle progression in our model is controlled by volumetric strain, the latter being derived from a bio-mechanical relation between applied pressure and cell compressibility.

Self-interference 3D super-resolution microscopy for deep tissue investigations.

Fluorescence localization microscopy has achieved near-molecular resolution capable of revealing ultra-structures, with a broad range of applications, especially in cellular biology. However, it remains challenging to attain such resolution in three dimensions and inside biological tissues beyond the first cell layer. Here we introduce SELFI, a framework for 3D single-molecule localization within multicellular specimens and tissues.

Organ size control via hydraulically gated oscillations.

Hollow vesicular tissues of various sizes and shapes arise in biological organs such as ears, guts, hearts, brains and even entire organisms. Regulating their size and shape is crucial for their function. Although chemical signaling has been thought to play a role in the regulation of cellular processes that feed into larger scales, it is increasingly recognized that mechanical forces are involved in the modulation of size and shape at larger length scales.

All-in-one 3D printed microscopy chamber for multidimensional imaging, the UniverSlide.

While live 3D high resolution microscopy techniques are developing rapidly, their use for biological applications is partially hampered by practical difficulties such as the lack of a versatile sample chamber. Here, we propose the design of a multi-usage observation chamber adapted for live 3D bio-imaging. We show the usefulness and practicality of this chamber, which we named the UniverSlide, for live imaging of two case examples, namely multicellular systems encapsulated in sub-millimeter hydrogel shells and zebrafish larvae.

Controlled production of sub-millimeter liquid core hydrogel capsules for parallelized 3D cell culture.

Liquid core capsules having a hydrogel membrane are becoming a versatile tool for three-dimensional culture of micro-organisms and mammalian cells. Making sub-millimeter capsules at a high rate, via the breakup of a compound jet in air, opens the way to high-throughput screening applications. However, control of the capsule size monodispersity, especially required for quantitative bioassays, was still lacking.

A 3D printed microfluidic device for production of functionalized hydrogel microcapsules for culture and differentiation of human Neuronal Stem Cells (hNSC).

We present here a microfluidic device that generates sub-millimetric hollow hydrogel spheres, encapsulating cells and coated internally with a layer of reconstituted extracellular matrix (ECM) of a few microns thick. The spherical capsules, composed of alginate hydrogel, originate from the spontaneous instability of a multi-layered jet formed by co-extrusion using a coaxial flow device. We provide a simple design to manufacture this device using a DLP (digital light processing) 3D printer.

Cellular capsules as a tool for multicellular spheroid production and for investigating the mechanics of tumor progression in vitro.

Deciphering the multifactorial determinants of tumor progression requires standardized high-throughput preparation of 3D in vitro cellular assays. We present a simple microfluidic method based on the encapsulation and growth of cells inside permeable, elastic, hollow microspheres. We show that this approach enables mass production of size-controlled multicellular spheroids.

Light-sheet microscopy in thick media using scanned Bessel beams and two-photon fluorescence excitation.

In this study we show that it is possible to successfully combine the benefits of light-sheet microscopy, self-reconstructing Bessel beams and two-photon fluorescence excitation to improve imaging in large, scattering media such as cancer cell clusters. We achieved a nearly two-fold increase in axial image resolution and 5-10 fold increase in contrast relative to linear excitation with Bessel beams. The light-sheet penetration depth could be increased by a factor of 3-5 relative to linear excitation with Gaussian beams.

Self-reconstructing sectioned Bessel beams offer submicron optical sectioning for large fields of view in light-sheet microscopy.

One of main challenges in light-sheet microscopy is to design the light-sheet as extended and thin as possible--extended to cover a large field of view, thin to optimize resolution and contrast. However, a decrease of the beam's waist also decreases the illumination beam's depth of field. Here, we introduce a new kind of beam that we call sectioned Bessel beam.

C-terminal domain of the Uup ATP-binding cassette ATPase is an essential folding domain that binds to DNA.

The Uup protein belongs to a subfamily of soluble ATP-binding cassette (ABC) ATPases that have been implicated in several processes different from transmembrane transport of molecules, such as transposon precise excision. We have demonstrated previously that Escherichia coli Uup is able to bind DNA. DNA binding capacity is lowered in a truncated Uup protein lacking its C-terminal domain (CTD), suggesting a contribution of CTD to DNA binding.