Automated Bio-AFM Generation of Large Mechanome Data Set and Their Analysis by Machine Learning to Classify Cancerous Cell Lines.

Mechanobiological measurements have the potential to discriminate healthy cells from pathological cells. However, a technology frequently used to measure these properties, i.e.

Bio-Impedance Spectroscopy of Retained Cells Using a Micro-Perforated Sensing Membrane Filtrating Whole Blood Samples under High Flowrate.

Blood filtration using micro-fabricated devices is an interdisciplinary topic of research and innovation driven by clinical applications in cytapheresis, cardiovascular disease monitoring, or liquid biopsy. In this paper, we demonstrate that a micro-perforated membrane can be equipped with sensing microelectrodes for detecting, in situ and in real-time, the capture of cellular material during ex vivo filtration of whole blood under high flow rates. This work describes the fabrication process of the sift and detection microdevice.

Scalable Generation of Pre-Vascularized and Functional Human Beige Adipose Organoids.

Obesity and type 2 diabetes are becoming a global sociobiomedical burden. Beige adipocytes are emerging as key inducible actors and putative relevant therapeutic targets for improving metabolic health. However, in vitro models of human beige adipose tissue are currently lacking and hinder research into this cell type and biotherapy development.

Hierarchical Superhydrophobic Device to Concentrate and Precisely Localize Water-Soluble Analytes: A Route to Environmental Analysis.

An efficient superhydrophobic concentrator is developed using a hierarchical superhydrophobic surface on which the evaporation of a sessile droplet (6 μL) drives the nonvolatile elements it contains on a predefined micrometric analytical surface (pedestal of 80 μm diameter). This hierarchical silicon surface exhibits a surface texture made of etched nanopillars and consists of micropillars and guiding lines, arranged in radial symmetry around the central pedestal. The guiding lines ensure the overall convergence of the sessile droplet toward the central pedestal during evaporation.

Cell Aggregate Assembly through Microengineering for Functional Tissue Emergence.

Compared to cell suspensions or monolayers, 3D cell aggregates provide cellular interactions organized in space and heterogeneity that better resume the real organization of native tissues. They represent powerful tools to narrow down the gap between in vitro and in vivo models, thanks to their self-evolving capabilities. Recent strategies have demonstrated their potential as building blocks to generate microtissues.

Compact system for laser Doppler velocimetry of blood flow.

This work describes the implementation of a compact system allowing measurement of blood flow velocity using laser Doppler velocimetry . The compact setup uses an optical fiber acting as an emitter and receptor of the signal. The signal is then recovered by a photodiode and processed using a spectrum analyzer.

Small-world networks of neuroblastoma cells cultured in three-dimensional polymeric scaffolds featuring multi-scale roughness.

Understanding the mechanisms underlying cell-surface interaction is of fundamental importance for the rational design of scaffolds aiming at tissue engineering, tissue repair and neural regeneration applications. Here, we examined patterns of neuroblastoma cells cultured in three-dimensional polymeric scaffolds obtained by two-photon lithography. Because of the intrinsic resolution of the technique, the micrometric cylinders composing the scaffold have a lateral step size of ~200 nm, a surface roughness of around 20 nm, and large values of fractal dimension approaching 2.

Interfacing cells with microengineered scaffolds for neural tissue reconstruction.

The development of cellular microenvironments suitable for neural tissue engineering purposes involves a plethora of research fields ranging from cell biology to biochemistry, neurosciences, physics, nanotechnology, mechanobiology. In the last two decades, this multi-disciplinary activity has led to the emergence of numerous strategies to create architectures capable of reproducing the topological, biochemical and mechanical properties of the extracellular matrix present in the central (CNS) and peripheral nervous system (PNS). Some of these approaches have succeeded in inducing the functional recovery of damaged areas in the CNS and the PNS to address the current lack of effective medical treatments for this type of injury.

Measure and characterization of the forces exerted by growing multicellular spheroids using microdevice arrays.

Growing multicellular spheroids recapitulate many features of expanding microtumours, and therefore they are an attractive system for biomechanical studies. Here, we report an original approach to measure and characterize the forces exerted by proliferating multicellular spheroids. As force sensors, we used high aspect ratio PDMS pillars arranged as a ring that supports a growing breast tumour cell spheroid.

Nanoscale Forces during Confined Cell Migration.

In vivo, immune cells migrate through a wide variety of tissues, including confined and constricting environments. Deciphering how cells apply forces when infiltrating narrow areas is a critical issue that requires innovative experimental procedures. To reveal the distribution and dynamics of the forces of cells migrating in confined environments, we designed a device combining microchannels of controlled dimensions with integrated deformable micropillars serving as sensors of nanoscale subcellular forces.

Dynamic inking of large-scale stamps for multiplexed microcontact printing and fabrication of cell microarrays.

Microcontact printing has become a versatile soft lithography technique used to produce molecular micro- and nano-patterns consisting of a large range of different biomolecules. Despite intensive research over the last decade and numerous applications in the fields of biosensors, microarrays and biomedical applications, the large-scale implementation of microcontact printing is still an issue. It is hindered by the stamp-inking step that is critical to ensure a reproducible and uniform transfer of inked molecules over large areas.

Protrusion Force Microscopy: A Method to Quantify Forces Developed by Cell Protrusions.

In numerous biological contexts, animal cells need to interact physically with their environment by developing mechanical forces. Among these, traction forces have been well-characterized, but there is a lack of techniques allowing the measurement of the protrusion forces exerted by cells orthogonally to their substrate. We designed an experimental setup to measure the protrusion forces exerted by adherent cells on their substrate.

Fabrication of Biomolecule Microarrays for Cell Immobilization Using Automated Microcontact Printing.

Biomolecule microarrays are generally produced by conventional microarrayer, i.e., by contact or inkjet printing.

Enhancing Plasticity of the Central Nervous System: Drugs, Stem Cell Therapy, and Neuro-Implants.

Stroke represents the first cause of adult acquired disability. Spontaneous recovery, dependent on endogenous neurogenesis, allows for limited recovery in 50% of patients who remain functionally dependent despite physiotherapy. Here, we propose a review of novel drug therapies with strong potential in the clinic.

Regenerative potential of primary adult human neural stem cells on micropatterned bio-implants boosts motor recovery.

Background: The adult brain is unable to regenerate itself sufficiently after large injuries. Therefore, hopes rely on therapies using neural stem cell or biomaterial transplantation to sustain brain reconstruction. The aim of the present study was to evaluate the improvement in sensorimotor recovery brought about by human primary adult neural stem cells (hNSCs) in combination with bio-implants.

Integration of solid-state nanopores into a functional device designed for electrical and optical cross-monitoring.

We present a new strategy for fabricating a silicon nanopore device allowing straightforward fluidic integration and electrical as well as optical monitoring. The device presents nanopores of diameters 10 nm to 160 nm, and could therefore be used to obtain solvent-free free-standing lipid bilayers from small unilamellar vesicles (SUV) or large unilamellar vesicles (LUV). The silicon chip fabrication process only requires front side processing of a silicon-on-insulator (SOI) substrate.

Multiphoton Direct Laser Writing and 3D Imaging of Polymeric Freestanding Architectures for Cell Colonization.

The realization of 3D architectures for the study of cell growth, proliferation, and differentiation is a task of fundamental importance for both technological and biological communities involved in the development of biomimetic cell culture environments. Here we report the fabrication of 3D freestanding scaffolds, realized by multiphoton direct laser writing and seeded with neuroblastoma cells, and their multitechnique characterization using advanced 3D fluorescence imaging approaches. The high accuracy of the fabrication process (≈200 nm) allows a much finer control of the micro- and nanoscale features compared to other 3D printing technologies based on fused deposition modeling, inkjet printing, selective laser sintering, or polyjet technology.

Podosome Force Generation Machinery: A Local Balance between Protrusion at the Core and Traction at the Ring.

Determining how cells generate and transduce mechanical forces at the nanoscale is a major technical challenge for the understanding of numerous physiological and pathological processes. Podosomes are submicrometer cell structures with a columnar F-actin core surrounded by a ring of adhesion proteins, which possess the singular ability to protrude into and probe the extracellular matrix. Using protrusion force microscopy, we have previously shown that single podosomes produce local nanoscale protrusions on the extracellular environment.

Corticospinal Tract Tracing in the Marmoset with a Clinical Whole-Body 3T Scanner Using Manganese-Enhanced MRI.

Manganese-enhanced MRI (MEMRI) has been described as a powerful tool to depict the architecture of neuronal circuits. In this study we investigated the potential use of in vivo MRI detection of manganese for tracing neuronal projections from the primary motor cortex (M1) in healthy marmosets (Callithrix Jacchus). We determined the optimal dose of manganese chloride (MnCl2) among 800, 400, 40 and 8 nmol that led to manganese-induced hyperintensity furthest from the injection site, as specific to the corticospinal tract as possible, and that would not induce motor deficit.

Evaluation of the force and spatial dynamics of macrophage podosomes by multi-particle tracking.

Podosomes are submicron adhesive and mechanosensitive structures formed by macrophages, dendritic cells and osteoclasts that are capable of protruding into the extracellular environment. Built of an F-actin core surrounded by an adhesion ring, podosomes assemble in a network interconnected by acto-myosin cables. They have been shown to display spatiotemporal instability as well as protrusion force oscillations.

Working together: spatial synchrony in the force and actin dynamics of podosome first neighbors.

Podosomes are mechanosensitive adhesion cell structures that are capable of applying protrusive forces onto the extracellular environment. We have recently developed a method dedicated to the evaluation of the nanoscale forces that podosomes generate to protrude into the extracellular matrix. It consists in measuring by atomic force microscopy (AFM) the nanometer deformations produced by macrophages on a compliant Formvar membrane and has been called protrusion force microscopy (PFM).

Large-scale assembly of single nanowires through capillary-assisted dielectrophoresis.

An innovative technique is proposed for the precise and scalable placement of 1D nanostructures in an affordable manner. This approach combines the dielectrophoresis phenomenon and capillary assembly to successfully align thousands of single nanowires at specific locations at the wafer. The nanowires are selectively trapped by taking advantage of the material--specific frequence dependence.

Protrusion force microscopy reveals oscillatory force generation and mechanosensing activity of human macrophage podosomes.

Podosomes are adhesion structures formed in monocyte-derived cells. They are F-actin-rich columns perpendicular to the substrate surrounded by a ring of integrins. Here, to measure podosome protrusive forces, we designed an innovative experimental setup named protrusion force microscopy (PFM), which consists in measuring by atomic force microscopy the deformation induced by living cells onto a compliant Formvar sheet.

Microdevice arrays of high aspect ratio poly(dimethylsiloxane) pillars for the investigation of multicellular tumour spheroid mechanical properties.

We report the design, fabrication and evaluation of an array of microdevices composed of high aspect ratio PDMS pillars, dedicated to the study of tumour spheroid mechanical properties. The principle of the microdevice is to confine a spheroid within a circle of micropillars acting as peripheral flexible force sensors. We present a technological process for fabricating high aspect ratio micropillars (300 μm high) with tunable feature dimensions (diameter and spacing) enabling production of flexible PDMS pillars with a height comparable to spheroid sizes.

Direct patterning of probe proteins on an antifouling PLL-g-dextran coating for reducing the background signal of fluorescent immunoassays.

The limit of detection of advanced immunoassays, biochips and micro/nano biodetection devices is impacted by the non-specific adsorption of target molecules at the sample surface. In this paper, we present a simple and versatile low cost method for generating active surfaces composed of antibodies arrays surrounded by an efficient anti-fouling layer, capable to decrease drastically the fluorescence background signal obtained after interaction with a solution to be analyzed. The technological process involves the direct micro-contact printing of the antibodies probe molecules on a pre-coated PLL-g-dextran thin layer obtained by contact printing using a flat PDMS stamp.