Recent evidence suggests that proinflammatory
cytokines, such as
tumor necrosis factor α (TNF-α), play a pivotal role in
the development of inflammatory-related pathologies (covid-19, depressive
disorders, sepsis, cancer, etc.,). More importantly, the development
of TNF-α biosensors applied to biological fluids (e.g. sweat)
could offer non-invasive solutions for the continuous monitoring of
these disorders, in particular, polydimethylsiloxane (PDMS)-based
biosensors. We have therefore investigated the biofunctionalization
of PDMS surfaces using a silanization reaction with 3-aminopropyltriethoxysilane,
for the development of a human TNF-α biosensor. The silanization
conditions for 50 μm PDMS surfaces were extensively studied
by using water contact angle measurements, electron dispersive X-ray
and Fourier transform infrared spectroscopies, and fluorescamine detection.
Evaluation of the wettability of the silanized surfaces and the Si/C
ratio pointed out to the optimal silanization conditions supporting
the formation of a stable and reproducible aminosilane layer, necessary
for further bioconjugation. An ELISA-type immunoassay was then successfully
performed for the detection and quantification of human TNF-α
through fluorescent microscopy, reaching a limit of detection of 0.55
μg/mL (31.6 nM). Finally, this study reports for the first time
a promising method for the development of PDMS-based biosensors for
the detection of TNF-α, using a quick, stable, and simple biofunctionalization
process.