Shah Nilam C, Lyandres Olga, Walsh Joseph T, Glucksberg Matthew R, Van Duyne Richard P
Chemistry Department, Northwestern University, Evanston, Illinois 60208, USA.
Anal Chem. 2007 Sep 15;79(18):6927-32. doi: 10.1021/ac0704107. Epub 2007 Aug 10.
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.
厌氧条件下乳酸的产生可指示人体的运动水平、疲劳程度和水合状态。乳酸水平升高是由多种病症引起的，包括充血性心力衰竭、缺氧和糖尿病酮症酸中毒。因此，实时检测乳酸对于监测这些病症、创伤后情况以及评估从事剧烈活动者的身体状况可能是有用的。本文展示了一种基于表面增强拉曼光谱（SERS）的乳酸传感器的概念验证。此外，它还为多分析物传感平台指明了方向。本文使用混合的癸硫醇/巯基己醇分配层来演示SERS乳酸传感。通过将传感器表面交替暴露于含乳酸的水溶液和不含乳酸的缓冲液中来表征传感器表面的可逆性。发现分配和去分配时间常数均约为30秒。此外，在磷酸盐缓冲盐溶液介质中使用多变量分析对生理乳酸水平（即6 - 240mg/dL）进行了定量，预测均方根误差为39.6mg/dL。最后，对葡萄糖和乳酸的连续暴露进行了可逆性测试。证明了两种分析物的完全分配和去分配。
