Infrared measurements of glucose in peritoneal fluid with a tuneable quantum cascade laser.

Ine L Jernelv,Astrid Aksnes,Dag Roar Hjelme

doi:10.1364/boe.393617

Abstract

Fast and accurate continuous glucose monitoring is needed in future systems for control of blood glucose levels in type 1 diabetes patients. Direct spectroscopic measurement of glucose in the peritoneal cavity is an attractive alternative to conventional electrochemical sensors placed subcutaneously. We demonstrate the feasibility of fast glucose measurements in peritoneal fluid using a fibre-coupled tuneable mid-infrared quantum cascade laser. Mid-infrared spectra (1200–925 cm−1) of peritoneal fluid samples from pigs with physiological glucose levels (32–426 mg/dL, or 1.8–23.7 mmol/L) were acquired with a tuneable quantum cascade laser employing both transmission and attenuated total reflection (ATR) spectroscopy. Using partial least-squares regression, glucose concentrations were predicted with mean absolute percentage errors (MAPEs) of 8.7% and 12.2% in the transmission and ATR configurations, respectively. These results show that highly accurate concentration predictions are possible with mid-infrared spectroscopy of peritoneal fluid, and represent a first step towards a miniaturised optical sensor for intraperitoneal continuous glucose monitoring.

Highlights

Challenges related to chronic illnesses, an ageing population, and increased healthcare costs have led to great interest in development of sensor solutions that enable real-time or point-of-care (POC) monitoring, such as glucose sensors for diabetic patients
Monitoring of blood glucose levels (BGLs) is crucial for treatment of diabetes in order to avoid short- and long-term effects related to low and high glucose levels for patients treated with insulin [1–3]
Accurate prediction of glucose concentrations in peritoneal fluid was achieved with QCLbased spectroscopy with 8.7% and 12.2% mean absolute percentage errors (MAPEs) in the transmission and attenuated total reflection (ATR) configurations, respectively

Summary

Introduction

Challenges related to chronic illnesses, an ageing population, and increased healthcare costs have led to great interest in development of sensor solutions that enable real-time or point-of-care (POC) monitoring, such as glucose sensors for diabetic patients. Monitoring of blood glucose levels (BGLs) is crucial for treatment of diabetes in order to avoid short- and long-term effects related to low (hypoglycaemia) and high (hyperglycaemia) glucose levels for patients treated with insulin [1–3]. Most commercially available glucose sensors are electrochemical and estimate glucose concentrations based on an enzymatic reaction, either with fingerprick measurements or with a continuous glucose monitoring (CGM) device worn on the body [4]. Mid-infrared (MIR) spectroscopy has several characteristics that are advantageous for POC monitoring. MIR spectroscopy can thereby produce relatively strong absorption bands with uniquely identifiable features. The commercial availability of tuneable quantum cascade lasers (QCLs) has opened up more avenues for MIR spectroscopy applications [6]. For non-invasive approaches, Werth et al [10]. showed glucose measurements based on backreflected light from the hand, while Kino et al [11]. determined glucose concentrations from measurements of the inner lip mucosa

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Conclusion