Rapid, low cost prototyping of transdermal devices for personal healthcare monitoring

•Microneedle structure based minimally invasive, transdermal sensors for measuring metabolites and drugs in the dermal compartment•These microneedle structures are fabricated by injection molding technology that has potential for mass production•Microneedle structures are mechanically robust against transverse and axial forces•Microneedle structures penetrate human skin and sit in the dermal interstitial space under moderate thumb pressure (< 10 N)•Microneedle structures can be easily modified to glucose, lactate and theophylline biosensor devices

The next generation of devices for personal healthcare monitoring will comprise molecular sensors to monitor analytes of interest in the skin compartment. Transdermal devices based on microneedles offer an excellent opportunity to explore the dynamics of molecular markers in the interstitial fluid, however good acceptability of these next generation devices will require several technical problems associated with current commercially available wearable sensors to be overcome. These particularly include reliability, comfort and cost. An essential pre-requisite for transdermal molecular sensing devices is that they can be fabricated using scalable technologies which are cost effective.We present here a minimally invasive microneedle array as a continuous monitoring platform technology. Method for scalable fabrication of these structures is presented. The microneedle arrays were characterised mechanically and were shown to penetrate human skin under moderate thumb pressure. They were then functionalised and evaluated as glucose, lactate and theophylline biosensors. The results suggest that this technology can be employed in the measurement of metabolites, therapeutic drugs and biomarkers and could have an important role to play in the management of chronic diseases.