Diagnostic and therapeutic devices based on polymeric microneedles: fabrication and preliminary results

Applications of microneedles in biomedicine wide range from diagnostics to therapeutics. This crucial and versatile tool is the interface between the human body and often a complicated device. We present two sensing device based on hybrid microneedles array for diagnostic and therapeutic applications. The hybrid microneedles was fabricated by using a commercial photocatalyzer to solidify a liquid PolyEthylene Glycol hydrogel. After polymerization, the MNs have a porous structure, which can include a variety of biological molecules, as bioprobes or drugs. The first device presented is an electrochemical sensor where microneedles include enzymes in their matrix that interact with glucose. It is fabricated by plating with gold the MNs and etching their tips. The redox reaction with glucose, mediated by ferrocene, creates a charge transfer resulting in a current proportional to the glucose concentration. The second device is a therapeutic tool with an optically controlled release of drugs. In this case the device includes a porous silicon membrane with a Bragg´s mirror, whose reflection wavelength is related to the drugs concentration in the MN.