Disposable plastic microreactors for genomic analyses.

We show the design, development and assessment of disposable, biocompatible, fully plastic microreactors, which are demonstrated to be highly efficient for genomic analyses, such as amplification of DNA, quantitative analyses in real time, multiplex PCR (both in terms of efficiency and selectivity), as compared to conventional laboratory equipment for PCR. The plastic microreactors can easily be coupled to reusable hardware, enabling heating/cooling processes and, in the case of qPCR applications, the real-time detection of the signal from a suitable fluorescent reporter present in the reaction mixture during the analysis. The low cost production of these polymeric microreactors, along with their applicability to a wide range of biochemical targets, may open new perspectives towards practical applications of biochips for point of care diagnostics.

Facile synthesis of 3D flower-like Pt nanostructures on polypyrrole nanowire matrix for enhanced methanol oxidation.

Here we report the simple and rapid synthesis of three-dimension Pt flower-like nanostructures (PtNFs) on a polypyrrole nanowires (PPyNWs) matrix. Both PtNFs and PPyNWs are prepared by an electrochemical approach without using any seed, template or surfactant. The morphology and chemical composition of the resulting PtNF/PPyNWs hybrids are characterized by scanning electron microscopy and by X-ray photoelectron spectroscopy, respectively. Taking methanol oxidation as a model catalysis reaction, the electrocatalytic performance of the as-prepared PtNF/PPyNWs system has been evaluated by cyclic voltammetry and chronoamperometry, evidencing that these 3D materials exhibit excellent electrocatalytic activity and high level of poisoning tolerance to the carbonaceous oxidative intermediates. Such electrocatalytic performances can be ascribed to the combined effect of the flower-like structure promoting the exposure of more sites and the polymer nanowires matrix endorsing high dispersion of PtNF on a high electrochemically active surface area, besides the removal of sub-products from electrocatalytic sites.

A simple approach to synthetize folic acid decorated magnetite@SiO2 nanostructures for hyperthermia applications.

Superparamagnetic magnetite nanoparticles were synthetized and capped by a SiO2 shell in order to avoid oxidation and aggregation of the iron oxide nanostructures. The inorganic capping was then further decorated by folic acid molecules, by using a very simple procedure exploiting supramolecular interactions among the organic moieties and the inorganic nanoparticles. The supramolecular nanoadduct thanks to folic acid molecules could act as a "Trojan horse" for the cancer cells and due to its superparamagnetic properties could induce local heat generation upon an appropriate magnetic field application. In fact, temperature was increased up to 42 °C when a 18 mT magnetic field was applied to the nanoparticles and the hybrid nanostructures were verified to be selectively internalized by HeLa cells, a human cervical cancer line known to overexpress the folic acid receptor.

Study of the surface morphology of a cholesteryl tethering system for lipidic bilayers.

The immobilization of functional molecules embedded in lipidic membranes onto inorganic substrates is of great interest for numerous applications in the fields of biosensors and biomaterials. We report on the preparation and the morphological characterization of a tethering system for lipidic bilayers, which is based on cholesteryl derivatives deposited on hydrophilic surfaces by self-assembling and microcontact printing techniques. The investigation of the structural properties of the realized films by atomic, lateral, and surface potential microscopy allowed us to assess the high quality of the realized cholesteryl layers.

Charge transport in disordered films of non-redox proteins.

Electrical conduction in solid state disordered multilayers of non-redox proteins is demonstrated by two-terminal transport experiments at the nanoscale and by scanning tunneling microscopy (STM/STS experiments). We also show that the conduction of the biomolecular films can be modulated by means of a gate field. These results may lead to the implementation of protein-based three-terminal nanodevices and open important new perspectives for a wide range of bioelectronic/biosensing applications.

Retention of nativelike conformation by proteins embedded in high external electric fields.

In this Communication, we show that proteins embedded in high external electric fields are capable of retaining a nativelike fold pattern. We have tested the metalloprotein azurin, immobilized onto SiO2 substrates in air with proper electrode configuration, by applying static fields up to 10(6)-10(7) Vm. The effects on the conformational properties of protein molecules have been determined by means of intrinsic fluorescence measurements. Experimental results indicate that no significant field-induced conformational alteration occurs. Such results are also discussed and supported by theoretical predictions of the inner protein fields.

Effects of 24-hour unilateral ureteral obstruction on glomerular hemodynamics in rat kidney.

Glomerular hemodynamics were studied, by micropuncture, in Munich-Wistar rats submitted to 24-hour unilateral ureteral ligation (UUL). Glomerular capillary pressure (PG), intratubular pressure (PT) and pressure in the first-order peritubular capillaries (EAP) were measured with a servonulling device. Single nephron filtration fraction (SNIFF) was calculated fmom arterial and peritubular blood protein concentration. SNGFR was both measured by conventional micropuncture techniques and calculated from efferent arteriole blood flow (EABF) and SNFF. Afferent arteriole blood flow (AABF) and resistance of afferent (Ra) and efferent (Re) arterioles were calculated. Measurements were repeated 1 to 2 hours after the release of the ureter. Sham-operated rats were used as control. UUL caused a marked increase in Ra (from 4.9 +/- [SD] 2.4 to 12.7 +/- 5.1 dynes/sec/cm-5). The fall in SNGFR (from 111.9 +/- [SD] 23.9 to 34.4 +/- 23.1 nl/min/kg body wt) was secondary to a decrease in both PG and AABF. A further increase in Ra (16.0 +/- 6.7 dynes.sec.cm-5) occurred after releasing the ureter. SNGFR, however, was unaltered (33.7 +/- 16.6 nl/min/kg body wt) since PG decreased parallel to PT, but AABF did not significantly change. Conclusion. Ureteral obstruction determines, in 24 hours, a marked cortical ischemia that is not promptly reversed by ureteral release.

Glomerular hemodynamics before and after release of 24-hour bilateral ureteral obstruction.

Glomerular hemodynamics were studied, by micropuncture, in Munich-Wistar rats submitted to 24-hour bilateral ureteral ligation (BUL). Glomerular capillary pressure (PG), intratubular pressure (PT), and pressure in the first order peritubular capillaries (EAP) were measured with a servonulling device. Single nephron filtration fraction (SNFF) was calculated from arterial and peritubular blood protein concentrations. Single nephron glomerular filtration rate (SNGFR) was both measured by conventional micropuncture techniques and calculated from efferent arteriole blood flow and SNFF. Afferent arteriole blood flow (AABF) and resistance of afferent (Ra) and efferent (Re) arteriole were calculated. Measurements were repeated in the left kidney after releasing the ureter. Sham operated rats were used as control. BUL caused a fall in SNGFR (from 101.8 +/- 9.7 to 40.7 +/- [SEM] 6.0 nl/min/kg body wt), accounted for by a rise in PT (from 14.1 +/- 0.7 to 28.9 +/- 3.1 mm Hg), glomerular hemodynamics (particularly PG and AABF) being unchanged. A marked increase in Ra (from 6.6 +/- 0.7 to 10.8 +/- 1.5 dynes. sec. cm-5) occurred after releasing the ureter, lessening both PG and AABF. Therefore, a low SNGFR was maintained despite the concomitant normalization of PT.

Ambipolar transistors based on azurin proteins.

A new type of transistor is presented. It is realised by using a metalloprotein; namely, azurin. Thanks to their natural functional characteristics, which involve inter- and intramolecular electron transfer, metalloproteins are good candidates for biomolecular nanoelectronics. The implementation of a prototype of protein transistor operating in air and in the solid state based on self-organised films of azurins is reported. Experimental current-voltage characteristics are shown. The new device presents an ambipolar behaviour as the gate bias voltage is changed. Exploiting this peculiar characteristic, a fully integrated logic gate which can be a good starting point for a new class of nanoelectronics devices has been realised.

Self-assembling of proteins and enzymes at nanoscale for biodevice applications.

Different nanotechnological strategies have been selected to implement biomolecular devices following a bottom-up or top-down approach depending on the biomolecule and on its functionality. Biomolecules have particular functionality and self-assembling capabilities that can be exploited for the implementation of both bioelectronic devices and multipurpose engineered biosurfaces. Surface preparation with supramolecular methods and microcontact printing have been developed and optimised to realise suitable functionalised surfaces. These surfaces can be used to link metalloproteins and enzymes for the implementation of nanobioelectronic devices and planar biosensors or to bind cells in order to promote their growth along predefined tracks and grooves. Some possible applications of these biosurfaces are shown and discussed. Results are presented for the realisation of a biomolecular nanodevice working in air based on the metalloprotein azurin immobilised in the solid state, the formation and characterisation of functional glutamate Dehydrogenase monolayers for nanobiosensing applications, the results of soft lithography processes on azurin for biosensor implementation, and the development of physiological self-assembled patterns of laminin-1 for cell culture applications and hybrid devices.