Flexible and stretchable wearable biomedical devices provide a platform for continues long-term monitoring of biological signals during neutral body movements thus enabling early intervention and diagnostics of various diseases. This thesis evaluates novel flexible and stretchable bio interfacing medical devices based on microneedle patches and split ring resonator for healthcare diagnostics. Flexible and stretchable microneedle patches were realized by integrating a soft polymer substrate with sharp stainless steel microneedles. This was realized using a magnetic assembly technique. Investigations have shown that the flexible microneedle patch can provide conformal and reliable contact with wrinkles and deformations of the skin. In addition, transdermal monitoring of potassium ions using the proposed flexible microneedle patch have been demonstrated by coating the microneedles with a potassium sensing membrane. Ex-vivo test on the microneedle potassium sensor performed on chicken and porcine skin was able to detect change in potassium concentration in the skin. Furthermore, a novel flexible bio-interface spilt ring resonator (SRR) for the monitoring of intera cranial pressure (ICP) is demonstrated. The sensor was fabricated by depositing a 500 nm gold film on a thermoset thiolene epoxy polymer substrate. The flexible sensor was able to clearly detect the pressure variation that might be an indication of increased ICP in the skull. The proposed methodology of heterogeneous integration of hard materials on a soft and flexible substrate demonstrates a first proof of concept of flexible wearable bio-interfacing devices with vastly different material properties with the potential for continuous and real-time health monitoring. / <p>QC 20190306</p>