Porous Colorimetric Microneedles valuable for monitoring blood glucose levels

These Biocompatible porous MNs can successfully penetrated rat skin. Because of internal pores, it extracted sufficient ISF for analysis relatively in a shorter time. They explained that the enzymes integrated with chromogenic agents on the porous MN sensor led to in situ visual colorimetric detection of glucose.

Using a smartphone, they analysed the colour intensity of the paper-based detection area, which quantified glucose levels. The usage was validated successfully on rat models and skin (varying glucose levels).

The findings are published in Biosensors.

Explaining research background, researchers said that in diabetes, monitoring blood glucose (BG) is indispensable. Frequent finger pricking (fingertip blood collection) causes discomfort. It also increases the risk of infection. Monitoring glucose in skin ISF is a good alternative due to the correlation between ISF glucose levels and blood glucose levels. So in this study, we developed a biocompatible porous microneedle. This was capable of rapid sampling, sensing, and glucose analysis in ISF in a minimally invasive manner. It can also improve patient compliance and detection efficiency.

The study results are:

• The microneedles contain glucose oxidase (GOx) and horseradish peroxidase (HRP).
• A colorimetric sensing layer containing 3,3′,5,5′-tetramethylbenzidine (TMB) was present on the back of the microneedles.
• Following penetration of rat skin, porous microneedles harvested ISF rapidly and smoothly via capillary action, triggering the production of hydrogen peroxide (H2O2) from glucose.
• In the presence of H2O2, HRP reacted with TMB contained in the filter paper on the back of microneedles.
• A visible Color shift was observed.

Further, a smartphone analysis of the images quickly quantifies glucose levels in the 50–400 mg/dL range using the correlation between colour intensity and glucose concentration.

The developed microneedle-based sensing technique with minimally invasive sampling will greatly affect point-of-care clinical diagnosis and diabetic health management.

They said the device is easily portable. Only finger pressure is used for obtaining glucose levels.

Fabricating an integrated, minimally invasive sampling and sensing platform can detect other biomarkers in ISF, enhancing patient compliance and detection.

Further reading:

Zeng, Q.; Xu, M.; Hu, W.; Cao, W.; Zhan, Y.; Zhang, Y.; Wang, Q.; Ma, T. Porous Colorimetric Microneedles for Minimally Invasive Rapid Glucose Sampling and Sensing in Skin Interstitial Fluid. Biosensors 2023, 13, 537. https://doi.org/10.3390/bios13050537