Optically monitored drug delivery patch based on porous silicon and polymer microneedles

Abstract

Fabrication and characterization of an optically monitored hybrid patch for local administration of drugs, based on polymeric micro-needles and a porous silicon free-standing membrane, are reported. The micro-needles are realized by an innovative photolithographic approach that allows fine tuning of geometrical parameters, using polyethylene glycol and a commercial photo-catalyzer. The porous silicon multilayer not only increases the storage of a relevant amount of the drug, but also offers a continuous, naked-eye monitoring of the drug delivery process. As a proof-of-concept experiment, we report our results on the release of a dye molecule (fluorescein, 332 Da) in a phosphate saline buffer.

Polymeric Microneedle Arrays: Versatile Tools for an Innovative Approach to Drug Administration

“…[19][20][21] If the geometry of the system and few process parameters, such as the time exposure and lamp power, are changed, different shapes (cylindrical, conical, or lancet-like) and lengths (from 100 up to 2000 µm) of MNs can be achieved. PEGDA, poured into a silicone vessel and exposed to ultraviolet light (365 nm) through a mask cross-links in the presence of a commercial photocatalyzer.…”

“…PEGDA, poured into a silicone vessel and exposed to ultraviolet light (365 nm) through a mask cross-links in the presence of a commercial photocatalyzer. [19][20][21] If the geometry of the system and few process parameters, such as the time exposure and lamp power, are changed, different shapes (cylindrical, conical, or lancet-like) and lengths (from 100 up to 2000 µm) of MNs can be achieved. Moreover, by changing the mask, which substantially means drawing a proper design with the computer, much more complicated structures can be straightforwardly obtained, such as hollow MNs, as shown in Figure 4.…”

“…based on a single‐step photolithographic process. PEGDA, poured into a silicone vessel and exposed to ultraviolet light (365 nm) through a mask cross‐links in the presence of a commercial photocatalyzer . If the geometry of the system and few process parameters, such as the time exposure and lamp power, are changed, different shapes (cylindrical, conical, or lancet‐like) and lengths (from 100 up to 2000 µm) of MNs can be achieved.…”

One-Shot Fabrication of Polymeric Hollow Microneedles by Standard Photolithography

“…Photolithography is a well-known fabrication technique in microelectronics and microfluidics, that enables the fabrication of solid MNs of several shapes and designed lengths. In [ 26 , 27 , 28 ], authors proposed a very easy fabrication method for solid and swelling MNs based on standard photolithography, where a mixture of Polyethylene glycol diacrylate (PEGDA) and a commercial photoinducer has been used as a negative photoresist, without any etching step. PEGDA is a biocompatible polymer that solidifies at room temperature in the presence of a photo-initiator using exposure to ultraviolet (UV) light for a few seconds.…”

Integrated Photodetectors Based on Group IV and Colloidal Semiconductors: Current State of Affairs

“…These include the innovative use of nanostructures with a negative effective refractive index capable of guiding light with very low losses [ 4 , 5 ] and switching its optical path through unprecedented effects [ 6 ]. Furthermore, the matching of processing technologies have paved the way for new devices integrated with fluidic, electronic, and photonic circuits for sensing detection and healthcare, which have led to the development of a new generation of biochips to be applied in fields ranging from biomedical to environmental [ 7 , 8 , 9 ].…”