title: Lactate and sequential lactate-glucose sensing using surface-enhanced Raman spectroscopy.
abstract: Lactate production under anaerobic conditions is indicative of human performance levels, fatigue, and hydration. Elevated lactate levels result from several medical conditions including congestive heart failure, hypoxia, and diabetic ketoacidosis. Real-time detection of lactate can therefore be useful for monitoring these medical conditions, posttrauma situations, and in evaluating the physical condition of a person engaged in strenuous activity. This paper represents a proof-of-concept demonstration of a lactate sensor based on surface-enhanced Raman spectroscopy (SERS). Furthermore, it points the direction toward a multianalyte sensing platform. A mixed decanethiol/mercaptohexanol partition layer is used herein to demonstrate SERS lactate sensing. The reversibility of the sensor surface is characterized by exposing it alternately to aqueous lactate solutions and buffer without lactate. The partitioning and departitioning time constants were both found to be approximately 30 s. In addition, physiological lactate levels (i.e., 6-240 mg/dL) were quantified in phosphate-buffered saline medium using multivariate analysis with a root-mean-square error of prediction of 39.6 mg/dL. Finally, reversibility was tested for sequential glucose and lactate exposures. Complete partitioning and departitioning of both analytes was demonstrated.
authors: Chemistry Department, Northwestern University, Evanston, Illinois 60208, USA.
authors: Nilam C
authors: NC
authors: Shah
authors: Olga
authors: O
authors: Lyandres
authors: Joseph T
authors: JT
authors: Walsh
authors: Matthew R
authors: MR
authors: Glucksberg
authors: Richard P
authors: RP
authors: Van Duyne
mesh_terms: D015374:Biosensing Techniques; D005947:Glucose / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D019344:Lactic Acid / Q000032:analysis / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D020349:Surface Plasmon Resonance / Q000379:methods*; D013499:Surface Properties
chemical_list: D019344:Lactic Acid; D005947:Glucose