Abstract
In this contribution, we propose a label-free
immunosensor, based on a novel type of electrolyte-gated
field-effect transistor (EGOFET), for ultrasensitive
detection of the C-reactive protein (CRP). The
recognition layer of the biosensor is fabricated by
physical adsorption of the anti-CRP monoclonal antibody
onto a poly-3-hexyl thiophene (P3HT) organic
semiconductor surface. A supplementary nonionic
hydrophilic polymer is used as a blocking agent
preventing nonspecific interactions and allowing a better
orientation of the antibodies immobilized onto the P3HT
surface. The whole biomolecule immobilization procedure
does not require any pretreatment of the organic
semiconductor surface, and the whole functionalization
process is completed in less than 30 min. Surface plasmon
resonance (SPR) measurements were performed to assess the
amount of biomolecules physisorbed onto the P3HT and to
evaluate the CRP binding proprieties of the deposited
anti-CRP layer. A partial surface coverage of about 23 %
of adsorbed antibody molecules was found to most
efficiently sense the CRP. The electrical performance of
the EGOFET immunosensor was comparable to that of a bare
P3HT EGOFET device, and the obtained CRP calibration
curve was linear over six orders of magnitude (from 4 pM
to 2 µM). The relative standard deviation of the
individual calibration points, measured on immunosensors
fabricated on different chips, ranged between 1 and 14 %,
and a detection limit of 2 pM (220 ng/L) was established.
The novel electronic immunosensor is compatible with
low-cost fabrication procedures and was successfully
employed for the detection of the CRP biomarker in the
clinically relevant matrix serum.
Original language | English |
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Pages (from-to) | 3943-3952 |
Journal | Analytical and Bioanalytical Chemistry |
Volume | 408 |
Issue number | 15 |
DOIs | |
Publication status | Published - 2016 |
MoE publication type | A1 Journal article-refereed |
Keywords
- C-reactive protein
- electrolyte-gated organic field-effect transistor
- immunosensor
- label-free electronic detection