Glucose detection at attomole levels using dynamic light scattering and gold nanoparticles

Glucose is directly related to brain activity and to diabetes. Therefore, developing a rapid and sensitive method for glucose detection is essential. Here, label-free glucose detection at attomole levels was realized by detecting the average diameter change of gold nanoparticles (AuNPs) utilizing dynamic light scattering (DLS). Single-strand DNA (ssDNA) adsorbed into the AuNPs’ surfaces and prevented them from aggregating in solution that contained NaCl. However, ssDNA cleaved onto ssDNA fragments upon addition of glucose, and these fragments could not adsorb onto the AuNPs’ surfaces. Therefore, in high-salt solution, AuNPs would aggregate and their average diameter would increase. Based on monitoring the average diameter of AuNPs with DLS, glucose could be detected in the range from 15 pmol/L to 2.0 nmol/L, with a detection limit of 8.3 pmol/L. Satisfactory results were also obtained when the proposed method was applied in human serum glucose detection.