Carbon-dot pequi-nut in the development of immunosensor to detect
pathogenic bacteria
Abstract
Carbon dots in biosensing have advanced significantly, adding
improvements to different detection techniques. In this study, an
amperometric immunosensor for Salmonella Thyphimurium was
designed using antibodies labeled with carbon dots (Cdots) from pequi
almond (Caryocar coriaceum). Cdots were synthesized by pyrolysis
and characterized by FTIR, UV/fluorescence, electrochemistry, zeta
potential, and transmission electron microscopy (TEM). A particle size
of 6.80 ± 2.13 nm was estimated, and the zeta potential was - 47.4 mV,
indicating the preponderant presence of acidic groups, as confirmed by
FTIR. The impedance evaluation of the response of biosensors assembled
for live (Rct = 13.4 kΩ) and dead (Rct = 499.7 Ω) Salmonella
showed a significant difference in their values, in agreement with
chronoamperometric analyses, which had their current values drastically
reduced from -2.2 mA (live) to 0 mA (dead). An analytical curve for
Salmonella was established with the limit of detection lower than
1 CFU/mL. This electrochemical biosensor using pequi carbon dots for
antibody labeling showed promising results for detecting the pathogen.
Thus, carbon dots can be used as substitutes for enzymes in labeling
antibodies used in the design and production of sensors.