Sensitive and non-invasive cholesterol determination in saliva via optimization of enzyme loading and platinum nano-cluster composition

Analyst. 2020 Feb 3;145(3):908-916. doi: 10.1039/c9an01679a.

Abstract

An excessive cholesterol level can lead to cardiovascular diseases, such as stroke, hypertension, and myocardial infarction. A non-invasive, painless method of determining the cholesterol level in blood would improve the user's convenience. To provide rapid and accurate determination of cholesterol, we have developed a simple, disposable, enzyme-based electrochemical biosensor that can detect salivary cholesterol. It is possible to detect low concentrations of cholesterol in saliva using the optimized vertical structure of the platinum nano-cluster (Pt-NC) and the immobilization of a proper volume of an enzyme. The biosensor exhibited a linear range from 2 to 486 μM, the limit of detection was about 2 μM, and the sensitivity of the sensor was calculated to be 132 μA mM-1 cm-2. It also showed good specificity for ascorbic acid, uric acid, dopamine, glucose, and lactate. In a test with an actual sample, the performance of the biosensor was confirmed by measuring total cholesterol in the saliva of a patient with hyperlipidemia. The cholesterol levels measured in the saliva of three patients with hyperlipidemia were 520, 460, and 290 μM. Therefore, the Pt-NC based enzyme sensor is a promising candidate for the detection of cholesterol in human saliva.

MeSH terms

  • Ascorbic Acid / chemistry
  • Biosensing Techniques / methods*
  • Cholesterol / analysis*
  • Cholesterol Oxidase / chemistry
  • Cholesterol Oxidase / metabolism
  • Electrochemical Techniques
  • Enzymes, Immobilized / chemistry
  • Enzymes, Immobilized / metabolism
  • Glucose / chemistry
  • Humans
  • Hyperlipidemias / diagnosis
  • Limit of Detection
  • Nanostructures / chemistry*
  • Platinum / chemistry*
  • Saliva / chemistry*
  • Uric Acid / chemistry

Substances

  • Enzymes, Immobilized
  • Uric Acid
  • Platinum
  • Cholesterol
  • Cholesterol Oxidase
  • Glucose
  • Ascorbic Acid