In vitro activation of the neuro-transduction mechanism in sensitive organotypic human skin model.

Recent advances in tissue engineering have encouraged researchers to endeavor the production of fully functional three-dimensional (3D) thick human tissues in vitro. Here, we report the fabrication of a fully innervated human skin tissue in vitro that recapitulates and replicates skin sensory function. Previous attempts to innervate in vitro 3D skin models did not demonstrate an effective functionality of the nerve network.

3D is not enough: Building up a cell instructive microenvironment for tumoral stroma microtissues.

Unlabelled: We fabricated three-dimensional microtissues with the aim to replicate in vitro the composition and the functionalities of the tumor microenvironment. By arranging either normal fibroblasts (NF) or cancer-activated fibroblasts (CAF) in two different three dimensional (3D) configurations, two kinds of micromodules were produced: spheroids and microtissues. Spheroids were obtained by means of the traditional cell aggregation technique resulting in a 3D model characterized by high cell density and low amount of extracellular proteins.

Label-free analysis of mononuclear human blood cells in microfluidic flow by coherent imaging tools.

The investigation of the physical properties of peripheral blood mononuclear cells (PBMC) is of great relevance, as they play a key role in regulating human body health. Here we report the possibility to characterize human PBMC in their physiological conditions in a microfluidic-based measurement system. A viscoelastic polymer solution is adopted for 3D alignment of individual cells inflow.

Shedding light on azopolymer brush dynamics by fluorescence correlation spectroscopy.

Understanding the response to illumination at a molecular level as well as characterising polymer brush dynamics are key features that guide the engineering of new light-stimuli responsive materials. Here, we report on the use of a confocal microscopy technique that was exploited to discern how a single molecular event such as the photoinduced isomerisation of azobenzene can affect an entire polymeric material at a macroscopic level leading to photodriven mass-migration. For this reason, a set of polymer brushes, containing azobenzene (Disperse Red 1, DR) on the side chains of poly(methacrylic acid), was synthesised and the influence of DR on the polymer brush dynamics was investigated for the first time by Fluorescence Correlation Spectroscopy (FCS).

Endogenous human skin equivalent promotes in vitro morphogenesis of follicle-like structures.

Three-dimensional constructs formed by cells embedded in an exogenous scaffold could not represent a faithful in vitro replica of native and functional tissues. In this work we produced an endogenous human skin equivalent by means of a tissue engineering process that induces the full morphogenesis of functional dermal and epidermal compartments. In such an organotypic context we demonstrated that -by using adult human skin cells-it is possible to generate follicle-like structures in vitro resembling what occurs in vivo in the fetal skin.

Room Temperature Consolidation of a Porous Poly(lactic-co-glycolic acid) Matrix by the Addition of Maltose to the Water-in-Oil Emulsion.

In composite materials made of polymer matrices and micro-nano dispersed compartments, the morphology of the dispersed phase can strongly affect several features of the final material, including stability, loading efficiency, and kinetic release of the embedded molecules. Such a polymer matrix composite can be obtained through the consolidation of the continuous polymer phase of a water-in-oil (W/O) emulsion. Here, we show that the morphology of the dispersed phase in a poly(lactic-co-glycolic acid, PLGA) matrix can be optimized by combining an effective mild temperature drying process with the addition of maltose as a densifying compound for the water phase of the emulsion.

From square to circular polymeric microchannels by spin coating technology: a low cost platform for endothelial cell culture.

Square microchannels are easy to fabricate by means of micromachining or lithographic techniques. However, in vitro vascular microcapillaries--as well as plug production and microparticle alignment--require mainly circular microchannels that can be used also in applications based on open microchannels. Nowadays, a simple, low cost, and versatile method to fabricate circular microchannels is still missing.

Confined Gelatin Dehydration as a Viable Route To Go Beyond Micromilling Resolution and Miniaturize Biological Assays.

Nowadays, microfluidic channels of a few tens of micrometers are required and widely used in many fields, especially for surface-processing applications and miniaturization of biological assays. Herein, we selected micromilling as a low-cost technology and proposed an approach capable of overcoming its limitations; in fact, microstructures below 20-30 μm in depth are difficult to obtain, and the manufacturing error is rather high, as it is inversely proportional to the depth. Indeed, the proposed method uses a confined dehydration process of a patterned gelatin substrate fabricated via replica molding onto a micromilled poly(methyl methacrylate) substrate to produce a gelatin master with demonstrated final micrometric features down to 3 μm for the channel depth and, in specific configurations, down to 5 μm for the channel width.

Functionalized poly(ethylene glycol) diacrylate microgels by microfluidics: In situ peptide encapsulation for in serum selective protein detection.

Polymeric microparticles represent a robustly platform for the detection of clinically relevant analytes in biological samples; they can be functionalized encapsulating a multiple types of biologics entities, enhancing their applications as a new class of colloid materials. Microfluidic offers a versatile platform for the synthesis of monodisperse and engineered microparticles. In this work, we report microfluidic synthesis of novel polymeric microparticles endowed with specific peptide due to its superior specificity for target binding in complex media.

Eicosyl ammoniums elicited thermal reduction alleyway towards gold nanoparticles and their chemo-sensor aptitude.

The construction of dimethylenebis(eicosyldimethylammonium bromide) surfactant-directed gold nanoparticles (NPs) has been accomplished via a one-pot thermal reduction of HAuCl4 with trisodium citrate. The effect of cationic twin-tail surfactants, dimethylenebis(hexadecyldimethylammonium bromide) (16-2-16), dimethylenebis(octadecyldimethylammonium bromide) (18-2-18) and dimethylenebis(eicosyldimethylammonium bromide) (20-2-20), and their concentrations on shape and size of Au nanoparticles was thoroughly investigated. The UV-Vis spectroscopy and transmission electron microscopy (TEM) results show that longer tail length surfactants act as shape-directing agents promoting diversified morphologies.

Excited-State Proton Transfer and Intramolecular Charge Transfer in 1,3-Diketone Molecules.

The photophysical signature of the tautomeric species of the asymmetric (N,N-dimethylanilino)-1,3-diketone molecule are investigated using approaches rooted in density functional theory (DFT) and time-dependent DFT (TD-DFT). In particular, since this molecule, in the excited state, can undergo proton transfer reactions coupled to intramolecular charge transfer events, the different radiative and nonradiative channels are investigated by making use of different density-based indexes. The use of these tools, together with the analysis of both singlet and triplet potential energy surfaces, provide new insights into excited-state reactivity allowing one to rationalize the experimental findings including different behavior of the molecule as a function of solvent polarity.

High sensitive and direct fluorescence detection of single viral DNA sequences by integration of double strand probes onto microgels particles.

A novel class of probes for fluorescence detection was developed and combined to microgel particles for a high sensitive fluorescence detection of nucleic acids. A double strand probe with an optimized fluorescent-quencher couple was designed for the detection of different lengths of nucleic acids (39 nt and 100 nt). Such probe proved efficient in target detection in different contests and specific even in presence of serum proteins.

An efficient planar accordion-shaped micromixer: from biochemical mixing to biological application.

Micromixers are the key component that allow lab-on-a-chip and micro total analysis systems to reach the correct level of mixing for any given process. This paper proposes a novel, simple, passive micromixer design characterized by a planar accordion-shape geometry. The geometrical characteristics of the presented design were analyzed numerically in the range of 0.

"On-Off" RGD Signaling Using Azobenzene Photoswitch-Modified Surfaces.

Photoresponsive surfaces were developed by modifying glass slides with switchable Gly-Arg-Gly-Asp-Ser (GRGDS) peptides to investigate light-controlled cell adhesion. The GRGDS peptide sequence was attached to an azobenzene moiety and then "clicked" to silanized glass substrates. The photoresponsive behavior of such cell-instructive materials (CIMs) was first checked by contact angle technique and by recording local changes in wettability owing to the isomerization of the azobenzene domain upon light stimulus.

Micropatterned Azopolymer Surfaces Modulate Cell Mechanics and Cytoskeleton Structure.

Physical and chemical characteristics of materials are important regulators of cell behavior. In particular, cell elasticity is a fundamental parameter that reflects the state of a cell. Surface topography finely modulates cell fate and function via adhesion mediated signaling and cytoskeleton generated forces.

Optical signature of erythrocytes by light scattering in microfluidic flows.

A camera-based light scattering approach coupled with a viscoelasticity-induced cell migration technique has been used to characterize the morphological properties of erythrocytes in microfluidic flows. We have obtained the light scattering profiles (LSPs) of individual living cells in microfluidic flows over a wide angular range and matched them with scattering simulations to characterize their morphological properties. The viscoelasticity-induced 3D cell alignment in microfluidic flows has been investigated by bright-field and holographic microscopy tracking, where the latter technique has been used to obtain precise cell alignment profiles in-flow.

Inhibitors of the apurinic/apyrimidinic endonuclease 1 (APE1)/nucleophosmin (NPM1) interaction that display anti-tumor properties.

The apurinic/apyrimidinic endonuclease 1 (APE1) is a protein central to the base excision DNA repair pathway and operates in the modulation of gene expression through redox-dependent and independent mechanisms. Aberrant expression and localization of APE1 in tumors are recurrent hallmarks of aggressiveness and resistance to therapy. We identified and characterized the molecular association between APE1 and nucleophosmin (NPM1), a multifunctional protein involved in the preservation of genome stability and rRNA maturation.

Nanoengineered surfaces for focal adhesion guidance trigger mesenchymal stem cell self-organization and tenogenesis.

The initial conditions for morphogenesis trigger a cascade of events that ultimately dictate structure and functions of tissues and organs. Here we report that surface nanopatterning can control the initial assembly of focal adhesions, hence guiding human mesenchymal stem cells (hMSCs) through the process of self-organization and differentiation. This process self-sustains, leading to the development of macroscopic tissues with molecular profiles and microarchitecture reminiscent of embryonic tendons.

A supramolecular two-photon-active hydrogel platform for direct bioconjugation under near-infrared radiation.

A supramolecular hydrogel assembled from partially methacrylated polyethyleneimine (PEI) and with direct photopatterning capabilities at near-infrared (NIR) wavelengths is presented. The chemically modified branched PEI macromolecules were characterized by FTIR and NMR spectroscopy to quantify the degree of methacrylation. A highly hydrophilic polymer network with a water content up to 95% was prepared.

Ligand engagement on material surfaces is discriminated by cell mechanosensoring.

Peptide or protein ligands can be used for molecular decoration to enhance the functionality of synthetic materials. However, some skepticism has arisen about the efficacy of such strategy in practical contexts since serum proteins largely adsorb. To address this issue, it is crucial to ascertain whether a chemically conjugated integrin-binding peptide is fully recognized by a cell even if partially covered by a physisorbed layer of serum protein; in more general terms, if competitive protein fragments physisorbed onto the surface are distinguishable from those chemically anchored to it.

Supramolecular spectrally encoded microgels with double strand probes for absolute and direct miRNA fluorescence detection at high sensitivity.

We present novel microgels as a particle-based suspension array for direct and absolute microRNA (miRNA) detection. The microgels feature a flexible molecular architecture, antifouling properties, and enhanced sensitivity with a large dynamic range of detection. Specifically, they possess a core-shell molecular architecture with two different fluorescent dyes for multiplex spectral analyses and are endowed with a fluorescent probe for miRNA detection.

Thermoresponsive PNIPAAm hydrogel scaffolds with encapsulated AuNPs show high analyte-trapping ability and tailored plasmonic properties for high sensing efficiency.

The fabrication of a scaffold able to control the positioning of AuNPs and to trap and concentrate target molecules inside them is a promising idea for a large variety of sensing applications. In this work, we designed and fabricated a scaffold of already-prepared 20 nm AuNPs encapsulated in a PNIPAAm hydrogel and utilizing surface enhanced Raman spectroscopy (SERS), we used it as a sensor with remarkably low limits of detection. In fact, as the target is trapped inside the hydrogel, the following takes place: (a) the concentration of the target increases dramatically and (b) the localization of the AuNPs and thus of the hotspots (areas with extremely high SERS enhancement factors) work synergistically, improving the sensing ability of the scaffold.

Rheometry-on-a-chip: measuring the relaxation time of a viscoelastic liquid through particle migration in microchannel flows.

A novel method to estimate the relaxation time of viscoelastic fluids, down to milliseconds, is here proposed. The adopted technique is based on the particle migration phenomenon occurring when the suspending viscoelastic fluid flows in microfluidic channels. The method is applied to measure the fluid relaxation times of two water-glycerol polymer solutions in an ample range of concentrations.