Ricerc@Sapienza

The emergence of nanosecond pulsed electric fields (nsPEFs) for intracellular manipulation experiments requires the use of specific miniaturized applicators. We propose the design of a versatile nsPEFs applicator, based on microwave propagating systems, suitable for in vitro exposure to undistorted 1-3 ns pulses in single and multi-cell experiments. Further features of the proposed devices are: high efficiency, microfluidic integration, real time monitoring of the biological sample and of the pulse propagation.

We have developed an EWOD system for lab-on-chip applications, comprising a new technology for EWOD implementation and the related electronic circuit driving. The new technology makes easier the integration of the EWOD technique with sensors and actuators usually present on lab-on-chip systems. It integrates an all-glass microfluidic network with an electrowetting structure, bonding together two glasses processed with microelectronics technologies.

Electrowetting-on-dielectric (EWOD) is a versatile tool in lab-on-chip systems since it controls fluid shape and flow by electrical signals alone without using external pumps and related tube connections. The most versatile EWOD configuration (allowing transport, division and mixing of droplets) is the closed one, where the fluid handling occurs between two coupled glasses.

This paper presents a low temperature technological process able to integrate an all-glass microfluidic network with an ElectroWetting On Dielectric (EWOD) structure for the digital handling of liquids. The fluidic channels result from the wet-etching of the glass, while the electrodes necessary for the droplet movement are deposited on the bottom and top surfaces of the microfluidic structure. The bottom electrodes are produced by a selective and sequential photolithographic pattern of a stack of metals, insulation layer and hydrophobic film.

In this paper, we present our studies on electrical and thermal tuning of light propagation in waveguide channels, made for the scope from a polydimethylsiloxane (PDMS) substrate infiltrated with nematic liquid crystal (LC). We demonstrated, via numerical simulations, the changes of the waveguide optical parameters when solicited by temperature changes or electric fields.

This paper develops a homogenization approach, based on the introduction of exact local and integral moments, to investigate the temporal evolution of effective dispersion properties of point-sized and finite-sized particles in periodic media. The proposed method represents a robust and computationally efficient continuous approach, alternative to stochastic dynamic simulations. As a case study, the exact moment method is applied to analyze transient dispersion properties of point-sized and finite-sized particles in sinusoidal tubes under the action of a pressure-driven Stokes flow.

Microfluidic channels filled with spatially periodic arrays of impermeable obstacles have been proved successful for the size-based continuous separation of mesoscopic objects suspended in a buffer solution with unprecedented resolution. To date however, this technique - referred to as Deterministic Lateral Displacement (DLD) - has been implemented only for small volume samples, mainly for analytical purposes. In this article, we investigate the feasibility of the DLD separation technique for water purification from bacteria.

Deterministic Lateral Displacement (DLD) is a relatively recent microfluidics-assisted technique which allows the size-based separation of a population of micrometric particles suspended in a buffer solution. The core of the device is a shallow channel with rectangular cross-section filled with an array of solid obstacles arranged in a spatially periodic lattice, whose directions are slanted with respect to the channel walls.

This paper reports on the development of a fluorescent label-free aptamer assay integrated in a lab-on-chip (LoC) system for the detection of Ochratoxin A (OTA). The detection system relies on the integration, on a single glass substrate, of an array of amorphous silicon photosensors and a long pass interferential filter. The aptamer assay, integrated into the microfluidic network, is an aptasensor having affinity versus OTA, selected as a case study. The fluorescent molecule is a "light switch" complex [Ru(phen)2(dppz)]2+.

This work presents a portable lab-on-chip system, based on thin film electronic devices and an all-glass microfluidic network, for the real-time monitoring of enzymatic chemiluminescent reactions. The microfluidic network is patterned, through wet etching, in a 1.1 mm-thick glass substrate that is subsequently bonded to a 0.5 mm-thick glass substrate. The electronic devices are amorphous silicon p-i-n photosensors, deposited on the outer side of the thinner glass substrate.