A Redox Mediator-Free
Highly Selective and Sensitive
Electrochemical Aptasensor for Patulin Mycotoxin Detection in Apple
Juice Using Ni–NiO Pseudocapacitive Nanomaterials
posted on 2024-03-07, 12:11authored byBrateen Datta, Praveena Bhatt, Gorachand Dutta
Pseudocapacitive nanomaterials have recently gained significant
attention in electrochemical biosensors due to their rapid response,
long cycle life, high surface area, biomolecule compatibility, and
superior energy storage capabilities. In our study, we introduce the
potential of using Ni–NiO nanofilm’s pseudocapacitive
traits as transducer signals in electrochemical aptasensors. Capitalizing
on the innate affinity between histidine and nickel, we immobilized
histidine-tagged streptavidin (HTS) onto Ni–NiO-modified electrodes.
Additionally, we employed a biolayer interferometry-based SELEX to
generate biotinylated patulin aptamers. These aptamers, when placed
on Ni–NiO–HTS surfaces, make a suitable biosensing platform
for rapid patulin mycotoxin detection in apple juice using electrochemical
amperometry in microseconds. The novelty lies in optimizing pseudocapacitive
nanomaterials structurally and electrochemically, offering the potential
for redox mediator-free electrochemical aptasensors. Proof-of-concept
is conducted by applying this surface for the ultrasensitive detection
of a model analyte, patulin mycotoxin. The aptamer-functionalized
bioelectrode showed an excellent linear response (10–106 fg/mL) and an impressive detection limit (1.65 fg/mL, +3σ
of blank signal). Furthermore, reproducibility tests yielded a low
relative standard deviation of 0.51%, indicating the good performance
of the developed biosensor. Real sample analysis in freshly prepared
apple juice revealed no significant difference (P < 0.05) in current intensity between spiked and real samples.
The sensor interface maintained excellent stability for up to 2 weeks
(signal retention 96.45%). The excellent selectivity, stability, and
sensitivity of the electrochemical aptasensor exemplify the potential
for using nickel-based pseudocapacitive nanomaterials for a wide variety
of electrochemical sensing applications.