Maria Fortuna Bevilacqua

A Photolithographic Approach to Polymeric Microneedles Array Fabrication

In this work, two procedures for fabrication of polymeric microneedles based on direct photolithography, without any etching or molding process, are reported. Polyethylene glycol (average molecular weight 250 Da), casted into a silicone vessel and exposed to ultraviolet light (365 nm) through a mask, cross-links when added by a commercial photocatalyzer. By changing the position of the microneedles support with respect to the vessel, different shapes and lengths can be achieved. Microneedles from a hundred microns up to two millimeters have been obtained just tuning the radiation dose, by changing the exposure time (5–15 s) and/or the power density (9–18 mW/cm2) during photolithography. Different microneedle shapes, such as cylindrical, conic or lancet-like, for specific applications such as micro-indentation or drug delivery, are demonstrated.

Multianalyte Biosensor Patch Based on Polymeric Microneedles

Multianalyte biosensor patch based on polymeric microneedles (MNs) have been fabricated by photolithography of poly (ethylene glycol) diacrylate (PEGDA) and have been dynamically characterized by means of quartz crystal microbalance and electrochemical measurements. The resulting flexible device acts as multianalyte working electrodes detecting glucose and lactic acid into interstitial liquid by means of redox reaction with glucose oxidase (GOx) and lactose oxidase (LOx) enzymes. Sensitivities of the order of nA mM−1 in the mM range are revealed in both case, after five minutes of swelling time and ten second of interaction.

Carbon nanotubes grown by catalytic CVD on silicon based substrates for electronics applications

To exploit the impressive electronic, mechanical and thermal properties of Carbon Nanotubes (CNTs) in the nanoelectronics technology, the development of deposition methods enabling the synthesis of well ordered, properly located and reproducible CNTs structures, is strongly recommended. We have been developing catalytic CVD synthesis of CNTs in order to get aligned nanotubes for applications ranging from nuclear particle-position detectors and cold cathode emitters for storage devices, to interconnects, vias and CNT-FETs. In this paper, the significant achievements gained on CVD growth processes for the CNTs deposition are presented. Ni and Fe catalyst nanoparticles have been obtained starting from thin films evaporated on silicon based substrates. The growth of vertically aligned carpets of MWNTs and horizontally aligned SWNTs, having a diameter of about 1 nm and bridging between patterned catalyst islands, has been accomplished. The SEM, TEM, Raman spectroscopy and AFM characterizations are discussed.