Ricerc@Sapienza

In this paper, we present an improved microfluidic network based on polydimethylsiloxane (PDMS) and thin film heaters for thermal treatment of biomolecules in lab-on-chip systems. It relies on the series connection of two thermally actuated valves, at both inlet and outlet of the network, in order to reduce leakage of sample when its process temperature approaches 100, °C. The spatial arrangement of valves and microfluidic channels in between has been optimized using COMSOL Multiphysics, through the investigation of the system thermal behavior.

This work combines a lab-on-chip device with an electronic system for the achievement of a small-scale and low-cost thermal treatment of biomolecules. The lab-on-chip is a 1.2 mm-thick glass substrate hosting thin film resistor acting as heater and, on the other glass side, amorphous silicon diodes acting as temperature sensors. The electronic system controls the lab-on-chip temperature through a Proportional-Integral-Derivative algorithm.

This work describes the design, fabrication and test of a lab-on-chip device along with its front-end electronics for the execution of experiments on bacterial cultures on nanosatellite missions. The motivations for such systems lie in the need to improve the quantification of the effects of the space environment on living organisms and facilitate the development of countermeasures to mitigate them.

This work presents an equivalent electrical circuit of hydrogenated amorphous silicon diodes. It is constituted by four diodes and two resistances. Each element is directly related to the physical behavior of the thin film structure and models the different conduction regimes of the device.Results show a very good fitting of the experimental current-voltage characteristic up to several hundreds of millivolts in both forward and reverse bias conditions and demonstrate the suitability of the developed model for designing the diode fabrication parameters for specific application.

This paper reports the development of a miniaturized lab-on-glass,suitable for the on-chip detection of living cell bioluminescence and their on-chip thermal treatments. The glass substrate hosts, on one side, hydrogenated amorphous silicon diodes, working as both temperature sensors and photosensors, and, on the other side, transparent thin films acting as heating sources. The main challenge of the work is the determination of the correct fabrication recipes in order to satisfy the compatibility of different microelectronic steps.

The study and quantification of the effects of the space environment on human body is a primary task for future manned deep space missions. The risk models for radiation exposures incurred by astronauts beyond low-Earth orbit, have different limitations due to the difficulty to have terrestrial parallels on which to base risk estimates. Indeed, no terrestrial sources fully reproduce the deep space energy spectrum and the multi directional flux of the cosmic radiation.

Lab-on-Chip System for Integrated Cell Culture Monitoring

Conductance spectroscopy, performed by measuring the electrical complex conductivity of the sample, can be a valid analytical method for cell cultures monitoring. The electromagnetic properties of inhomogeneous materials, and in particular of biological materials, are expressed in terms of complex conductivity, or permittivity, and are strictly related to shape, dimensions, volume fraction occupied by the particulate (cells) [1].

The assurance of food and feed safety, including the identification and effective monitoring of multiple bio- logical and chemical hazards, is a major societal challenge, given the increasing pace at which food com- modities are demanded, produced and traded across the globe. Within this context, mycotoxins are globally widespread secondary fungal metabolites, which can contaminate crops either in the field or during storage and have serious human and animal health impacts such as carcinogenic, teratogenic and hepatotoxic effects.

Here we present the design of an amorphous silicon photodetector integrated with an ion-exchanged waveguide on the same glass substrate in order to obtain an evanescent waveguide sensor for on-chip biomolecular recognition in Lab-on-Chip applications. We studied the behaviour of a monochromatic light in a channel waveguide and its coupling into the thin-film sensor, using COMSOL Multiphysics. Simulations show that the presence of the photodiode’s insulation layer and transparent electrode strongly affects the coupling efficiency between the waveguide and the sensor.