title: Aptamer-graphene oxide for highly sensitive dual electrochemical detection of Plasmodium lactate dehydrogenase.
abstract: A 90 mer ssDNA aptamer (P38) enriched against Plasmodium falciparum lactate dehydrogenase (PfLDH) through SELEX process was immobilized over glassy carbon electrode (GCE) using graphene oxide (GO) as an immobilization matrix, and the modified electrode was investigated for detection of PfLDH. The GO was synthesized from powdered pencil graphite and characterized by XRD based on the increased interlayer distance between graphitic layers from 0.345 nm for graphite to 0.829 nm for GO. The immobilization of P38 on GO was confirmed by ID/IGintensity ratio in Raman spectra where, the ratio were 0.67, 0.915, and 1.35 for graphite, GO and P38-GO, respectively. The formation of the P38 layer over GO-GCE was evident from an increase in the surface height in AFM analysis of the electrode from ∼3.5 nm for GO-GCE to ∼27 nm for P38-GO-GCE. The developed aptasensor when challenged with the target, a detection of as low as 0.5 fM of PfLDH was demonstrated. The specificity of the aptasensor was confirmed through a voltametric measurement at 0.65 V of the reduced co-factor generated from the PfLDH catalysis. Studies on interference from some common proteins, storage stability, repeatability and analysis of real samples demonstrated the practical application potential of the aptasensor.
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India.
authors.forename: Priyamvada
authors.initials: P
authors.lastname: Jain
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India.
authors.forename: Smita
authors.initials: S
authors.lastname: Das
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India.
authors.forename: Babina
authors.initials: B
authors.lastname: Chakma
authors.affiliation: Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam 781039, India. Electronic address: pgoswami@iitg.ernet.in.
authors.forename: Pranab
authors.initials: P
authors.lastname: Goswami
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D055664:Electrochemical Techniques / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D004867:Equipment Design; D006108:Graphite / Q000737:chemistry; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000032:analysis* / Q000097:blood; D010087:Oxides / Q000737:chemistry; D010963:Plasmodium falciparum / Q000201:enzymology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D052157:Aptamers, Nucleotide; D010087:Oxides; D006108:Graphite; D007770:L-Lactate Dehydrogenase
keywords: Aptamer; Electrochemical; Graphene oxide; Impedimetry; Malaria; Voltametry