Easy fabrication of aligned PLLA nanofibers-based 2D scaffolds suitable for cell contact guidance studies.

An easy, low-cost and fast wet processing-based method named ASB-SANS (Auxiliary Solvent-Based Sublimation-Aided NanoStructuring) has been used to fabricate poly(l-lactic acid) (PLLA) highly ordered and hierarchically organized 2D fibrillar patterns, with fiber widths between 40 and 500 nm and lengths exceeding tens of microns. A clear contact guidance effect of these nanofibrillar scaffolds with respect to HeLa and NIH-3T3 cells growth has been observed, on top of an overall good viability. For NIH-3T3 pronounced elongation of the cells was observed, as well as a remarkable ability of the patterns to guide the extension of pseudopodia. Moreover, SEM imaging revealed filopodia stemming from both sides of the pseudopodia and aligned with the secondary PLLA nanofibrous structures created by the ASB-SANS procedure. These results validate ASB-SANS as a technique capable to provide biocompatible 2D nanofibrillar patterns suitable for studying phenomena of contact guidance (and, more in general, the behavior of cells onto nanofibrous scaffolds), at very low costs and in an extremely easy way, accessible to virtually any laboratory.

Toward Low-Voltage and Bendable X-Ray Direct Detectors Based on Organic Semiconducting Single Crystals.

Organic materials have been mainly proposed as ionizing radiation detectors in the indirect conversion approach. The first thin and bendable X-ray direct detectors are realized (directly converting X-photons into an electric signal) based on organic semiconducting single crystals that possess enhanced sensitivity, low operating voltage (≈5 V), and a minimum detectable dose rate of 50 µGy s(-1) .

A home-made system for IPCE measurement of standard and dye-sensitized solar cells.

A home-made system for incident photon-to-electron conversion efficiency (IPCE) characterization, based on a double-beam UV-Vis spectrophotometer, has been set up. In addition to its low cost (compared to the commercially available apparatuses), the double-beam configuration gives the advantage to measure, autonomously and with no need for supplementary equipment, the lamp power in real time, compensating possible variations of the spectral emission intensity and quality, thus reducing measurement times. To manage the optical and electronic components of the system, a custom software has been developed. Validations carried out on a common silicon-based photodiode and on a dye-sensitized solar cell confirm the possibility to adopt this system for determining the IPCE of solar cells, including dye-sensitized ones.

A new standardized electrochemical array for drug metabolic profiling with human cytochromes P450.

Over the past two decades, a wealth of information on the human cytochrome P450 enzymes and their role in drug metabolism both in vitro and in vivo has been gathered. Our understanding of this area has progressed greatly, but our confidence in the development of quantitative projections of drug interactions, made from in vitro data, is somehow still shaky. There are therefore no doubts in the necessity for reliable and fast methodologies for P450 drug metabolism analysis, capable of providing accurate and precise in vitro data. This paper reports on the first integration of a P450-electrode into a microtiter plate format for the rapid determination of the affinity parameters (K(M)) for a set of known drugs. The most relevant human drug metabolizing cytochromes P450, isoforms 3A4, 2D6, and 2C9, have been covalently bound to a gold electrode via a 10-carboxydecanethiol and 8-hydroxyoctanethiol (1:1) self-assembled monolayer at the bottom of an eight-well microtiter plate. The electrochemical response of the P450-electrode and the performance of the platform have been validated using a set of 30 known drugs with K(M) values spanning from less than 1 to more than 100 µM. The K(M) values obtained using this platform show an excellent error, and their ranking is within the range of those present in the literature determined from conventional incubation experiments with cytochrome P450s 3A4, 2D6, and 2C9.

An electrochemical microfluidic platform for human P450 drug metabolism profiling.

This paper is the first report of a P450-electrode in a microfluidic format. A 30 µL microfluidic cell was made in poly(methyl methacrylate) containing the inlet, outlet, and reaction chamber with two electrode strips, one of which contains the human cytochrome P450 3A4 covalently bound to gold via a 6-hexanethiol and 7-mercaptoheptanoic acid (1:1) self-assembled monolayer. The electrochemical response of the P450-electrode in the microfluidic cell was tested using four drugs that are known substrates of P450 3A4: quinidine, nifedipine, alosetron and ondansetron. Titration experiments allowed the electrochemical measurements of K(M) for the four drugs, with values of 2.9, 29.1, 113.4, and 114.1 mM, respectively. The K(M) values are found to be in good agreement and correctly ranked with respect to the published literature on human liver microsomes and baculosomes: [ondansetron ≈ alosetron > nifedipine > quinidine]. The results presented in this paper represent a step forward for a rapid evaluation of the interaction of P450 and drug, requiring small volumes of new chemical entities to be tested.