title: Progress toward an in vivo surface-enhanced Raman spectroscopy glucose sensor.
abstract: BACKGROUND
  In this report, we detail our current work towards developing a surface-enhanced Raman spectroscopy (SERS) based sensor for in vivo glucose detection. Despite years of innovations in the development of blood glucose monitors, there remains a need for accurate continuous glucose sensors to provide care to rising numbers of diagnosed diabetes patients and mitigate secondary health complications associated with this metabolic disorder.
  
  
  METHODS
  SERS is a highly specific and sensitive optical technique suitable for direct detection of glucose. The SERS effect is highly distance dependent, thus the glucose molecules need to be within a few nanometers or adsorbed to an SERS-active surface. In our sensor, this is achieved with a self-assembled monolayer (SAM) that facilitates reversible interactions between glucose molecules and the surface. The amount of glucose near the surface is proportional to its concentration in the surrounding environment.
  
  
  RESULTS
  We determined that the SAM-functionalized surface is stable for at least 10 days and provides rapid, reversible partitioning. In vitro experiments in bovine plasma as well as in vivo experiments in rats demonstrated quantitative detection.
  
  
  CONCLUSIONS
  We show successful use of the SERS glucose sensor in rats, making it the first in vivo SERS sensor. Furthermore, we demonstrate free space transdermal detection of a SERS signal through the rat's skin as an initial step toward developing a transcutaneous sensor.
authors: Biomedical Engineering Department, Northwestern University, Evanston, Illinois 60208, USA.
authors: Olga
authors: O
authors: Lyandres
authors: Jonathan M
authors: JM
authors: Yuen
authors: Nilam C
authors: NC
authors: Shah
authors: Richard P
authors: RP
authors: VanDuyne
authors: Joseph T
authors: JT
authors: Walsh
authors: Matthew R
authors: MR
authors: Glucksberg
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000032:analysis*; D002138:Calibration; D003920:Diabetes Mellitus / Q000097:blood / Q000188:drug therapy; D045604:Extracellular Fluid / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: D001786:Blood Glucose