Patrick Griss

Abstract: This paper presents penetration-enhanced hollow microneedles and an analysis on the biomechanical interaction between microneedles and skin tissue. The aim of this paper is to fabricate microneedles that reliably penetrate the skin tissue without using penetration enhancers or special insertion tools that were used in the previous studies. The microneedles are made of silicon and feature ultrasharp tips and side openings. The microneedle chips were experimentally tested in vivo by injection of dye markers. To further investigate the penetration, the insertion progression and the insertion force were monitored by measuring the electrical impedance between microneedles and a counter electrode on the skin. The microneedle design was also tested using a novel simulation approach and compared to other previously published microneedle designs. The purpose of this specific part of the paper was to investigate the interaction mechanisms between a microneedle and the skin tissue. This investigation is used to predict how the skin deforms upon insertion and how microneedles can be used to create a leak-free liquid delivery into the skin. The fabricated microneedles successfully penetrated dry living human skin at all the tested sites. The insertion characteristic of the microneedle was superior to an earlier presented type, and the insertion force of a single microneedle was estimated to be below 10 mN. This low insertion force represents a significant improvement to earlier reported results and potentially allows a microneedle array with hundreds of needles to be inserted into tissue by hand.

TL;DR: The characterization of dry spiked biopotential electrodes is presented and their suitability to be used in anesthesia monitoring systems based on the measurement of electroencephalographic signals is tested and it is found that the spiked electrode is very comfortable for the patient.

TL;DR: The feasibility of a patch-like system with on-board liquid storage and dispensing capability with integrated active dispensing functionality is shown, which represents a first step towards painless and convenient administration of macromolecular drugs such as insulin or vaccines.

TL;DR: This study presents a novel possibility of insulin delivery that is controllable and requires minimal training and could improve compliance, and thus be beneficial for patients’ glycaemic control.