posted on 2023-11-24, 00:35authored byMinh-Dat Nguyen, Khoa-Nam Nguyen, Samuel Malo, Indrani Banerjee, Donghui Wu, Laurence Du-Thumm, Philippe Dauphin-Ducharme
Although
blood remains a gold standard diagnostic fluid for most
health exams, it involves an unpleasant and relatively invasive sampling
procedure (finger pricking or venous draw). Saliva contains many relevant
and useful biomarkers for diagnostic purposes, and its collection,
in contrast, is noninvasive and can be obtained with minimal effort.
Current saliva analyses are, however, achieved using chromatography
or lateral flow assays, which, despite their high accuracy and sensitivity,
can demand expensive laboratory-based instruments operated by trained
personnel or offer only semiquantitative results. In response, we
investigated electrochemical aptamer-based (E-AB) biosensors, a reagentless
sensing platform, to allow for continuous and real-time measurements
directly in undiluted, unstimulated human whole saliva. As a proof-of-concept
study, we developed E-AB biosensors capable of detecting low-molecular-weight
analytes (glucose and adenosine monophosphate (AMP)). To our knowledge,
we report the first E-AB sensor for glucose, an approach that is inherently
independent of its chemical reactivity in contrast to home glucometers.
For these three sensors, we evaluated their figures of merits, stability,
and reusability over short- and long-term exposure directly in saliva.
In doing so, we found that E-AB sensors allow rapid and convenient
molecular measurements in whole saliva with unprecedented sensitivities
in the pico- to nanomolar regime and could be regenerated and reused
up to 7 days when washed and stored in phosphate-buffered saline at
room temperature. We envision that salivary molecular measurements
using E-AB sensors are a promising alternative to invasive techniques
and can be used for improved point-of-care clinical diagnosis and
at-home measurements.