(134d) Non-Invasive Plasmonic Biosensors for in Situ Glucose Monitoring

Careful management of blood glucose level via frequent monitoring for diabetic patients is very important especially in the absence of a cure. The electrochemical detection based technologies remain the main focus of widely used commercially available finger stick testings for monitoring blood glucose level. However, the technological advancements have opened new avenues for alternative methods that will bring the ease of use and comfort for frequent users. Especially, label-free optical approaches have attracted a considerable attention. Here with this work, we propose a non-invasive plasmonic biosensor design for in situ glucose monitoring from the body fluid (interstitial fluid) using Surface Enhanced Raman Spectroscopy (SERS). The plasmonic device is composed of an array of polymeric microneedles and integrated with plasmonic component, metal nanoparticles, that are localized on the microneedles surface. The plasmonic component is chemically modified with self-assembled monolayer of glucose capture ligand. In situ sensing mechanism relies on capturing glucose from interstitial fluid on the metal nanoparticle surface once the device is pierced in the skin and real-time detecting SERS fingerprints of the capture ligand for quantitative analysis. Our initial findings showed that the plasmonic biosensor is SERS active when the device is inserted in a synthetic skin mimicking model (skin phantom). The highest SERS activity was observed at the microneedles tip. It is very important to show the mechanical and functional stability of the plasmonic device upon piercing to the skin and under exposure to the body fluid. The stability tests demonstrated that the proposed plasmonic device maintains its structural integrity and confirmed mechanical stability upon multiple piercing in the skin phantom. Additionally, metal nanoparticles stay intact on the polymer microneedles as the device is kept in the body fluid mimicking buffer condition over a month. Finally, the biosensing capability of the developed plasmonic device as well as its continuous glucose monitoring capacity will be discussed.