Graphene quantum dots-based nanocomposite for electrocatalytic application of L-cysteine in whole blood and live cells

P. Arul, Sheng Tung Huang, Veerappan Mani, Chih Hung Huang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Driven by the urgent need to detect amino acids in live cells at trace levels, as they are an important biomarker for various diseases. For this purpose, we have developed a nanomolar level detection of L-cysteine (L-Cys) and real-time cellular quantification from live cells based on graphene quantum dots (GQDs)-AuNPs-metal-free organic framework (MFOF). Different analytical and microscopic techniques were used to confirm the synthesized nanocomposite. The sensitive electrochemical sensing system of L-Cys-was detected synergistically with GQDs-AuNPs-MFOF/GCE by voltammetry and amperometric i-t curve. The electrocatalytic oxidation signal of L-Cys-at Epa = none, +0.45, +0.36 and +0.21 V (vs. Ag/AgCl) with enhanced current responses were observed at control GCE, MFOF, GQDs-MFOF, and GQDs-AuNPs-MFOF/GCEs by DPV. The nanocomposite modified sensor probe showed a wide linear range concentration from 1 nM to 0.5 mM with LOD of 0.124 nM (S/N = 3), LOQ of 0.863 nM (S/N = 10) and sensitivity of 2.364 μA μM−1 cm−2. Subsequently, the selective detection of L-Cys-in the presence of possible other interfering biothiols. amino acids, and metal ions were achieved. The practical application was demonstrated in human whole blood and bio-fluid samples. Finally, the endogenous real-time detection of cellular cysteine in live cells was demonstrated.
Original languageEnglish (US)
Pages (from-to)140937
JournalElectrochimica Acta
StatePublished - Aug 8 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-09-14
Acknowledgements: The authors are grateful for the financial support from the Ministry of Science and Technology, Taiwan (MOST-107–2113-M-027–006 and MOST-108–2113-M-027–001). P. Arul would like to gratitude National Taipei University of Technology for the position of Research Assistant Professor.

ASJC Scopus subject areas

  • General Chemical Engineering
  • Electrochemistry


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