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Practical considerations for micro/nanotechnology enabled biosensors

The field of biosenso­­­rs, driven among others by recent advances in micro and nanotechnologies, has seen the development of ultra-sensitive sensors. The progress has been such that the limit of detection of many micro/nano-sensors is low enough for the early diagnosis of a range of diseases. The deployment of such sensors at the point of care would greatly improve patients’ quality of life by providing rapid feedback and enabling swift, potentially life-saving procedures and treatments.

by Jerome Charmet, Assistant Professor in Biomedical Engineering.

The field of biosenso­­­rs, driven among others by recent advances in micro and nanotechnologies, has seen the development of ultra-sensitive sensors. The progress has been such that the limit of detection of many micro/nano-sensors is low enough for the early diagnosis of a range of diseases. The deployment of such sensors at the point of care would greatly improve patients’ quality of life by providing rapid feedback and enabling swift, potentially life-saving procedures and treatments. However, the higher sensitivity of micro/nano-sensors has revealed a range of issues that need to be addressed before they can be deployed in clinical settings. For example, these sensors are now capable of detecting biological processes interfering with the measurement and that were not detected with older generation, lower sensitivity sensors. Moreover, the decrease in the sensors capture area (linked to an increase in sensitivity for a range of sensors) puts a burden on the limit of detection of such sensors through a reduction of the number of captured analyte molecules. In my work, I have established how the measurements are influenced by the heterogeneity and stochastic nature of biological processes in the sensing environment. In particular, I have examined the situation when analyte molecules are bound sparsely at random locations on the sensor interface. Such a configuration, that is common in many real-life situations, make the interpretation of the measurement particularly challenging for a range of micro/nano-sensors that have a location-dependent sensitivity (Fig. 1) such as mechanical sensors, localised plasmon sensors and some electrochemical sensors amongst others. I have proposed a few strategies to overcome these issues and in particular, I have shown that the quantification of the measurement variations due to stochastic processes can be used to define new statistical methods enabling high resolutions sensing without compromising the sensitivity of mechanical sensors. The strategy presented can also be adapted to other sensor with location dependent sensitivity. I am currently evaluating complementary strategies, including microfluidics-based approaches to improve measurement resolution.

 Due to the location dependent sensitivity of mechanical sensors (and of a range of other micro/nano-sensors), the same number of analyte molecules, binding at different location on the sensor, will result in different measurements. This issue is particularly relevant for high resolution sensing and common in many real-life situations.

Due to the location dependent sensitivity of mechanical sensors (and of a range of other micro/nano-sensors), the same number of analyte molecules, binding at different location on the sensor, will result in different measurements. This issue is particularly relevant for high resolution sensing and common in many real-life situations.

 

You can read more in the associated publication:

J. Charmet et al., Phys. Rev. Appl. (2016) 5, 064016.

https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.5.064016

Mon 06 March 2017, 10:16 | Tags: bionsensors, Author: Jerome Charmet