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Carbon-dot pequi-nut in the development of immunosensor to detect pathogenic bacteria
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  • Rachel Menezes,
  • Marília Oliveira,
  • Roselayne Furtado,
  • Bruno Oliveira,
  • Lucas Martoni,
  • Terezinha Machado,
  • Celli Muniz,
  • Flávia Abreuu,
  • Sergio Machado,
  • Airis Melo,
  • Huai Cheng,
  • Atanu Biswas,
  • Carlucio Alves
Rachel Menezes
UECE
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Marília Oliveira
UECE
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Roselayne Furtado
EMBRAPA Agroindustrial Tropical

Corresponding Author:[email protected]

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Bruno Oliveira
UFCA
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Lucas Martoni
USP
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Terezinha Machado
EMBRAPA Agroindustrial Tropical
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Celli Muniz
EMBRAPA Agroindustrial Tropical
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Flávia Abreuu
UECE
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Sergio Machado
USP
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Airis Melo
IFPI Picos
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Huai Cheng
USDA Agricultural Research Service
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Atanu Biswas
USDA Agricultural Research Service
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Carlucio Alves
UECE
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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.