title: Impedimetric genosensor for ultratrace detection of hepatitis B virus DNA in patient samples assisted by zeolites and MWCNT nano-composites.
abstract: Nanocrystals of zeolites (Nanocrys Zeo) and Multi-walled carbon nanotubes (MWCNT) based diagnostic genosensor was employed for detection of polymerase chain (PCR) amplified HBVDNA in blood of hepatitis B patients. The ssDNA-nanocomposite modified electrode was characterized by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). The hybridization between ss DNA probe and target ss DNA was detected by reduction in current, generated by interaction of methylene blue (MB) with free guanine (3'G) of ssDNA. Nanocrys zeo were deposited on the Fluorine doped tin oxide glass electrode (FTO) by drop-casting method for better immobilization of ss DNA while MWCNTs are incorporated into the zeolite-assembly to enhance the electro-conductivity of the present genosensor. The ssDNA-nanocomposite modified FTO electrode exhibited optimum current within 5s, at pH 5.6, and incubation temperature of 45°C. The value of charge transfer resistance (Rct) was linear with the number of copies of target DNA between 150 and 10(6) copies/ml. The limit of detection (LOD) of the sensor was 50 copies/ml. Within and between batches coefficients of variation (CV) were 2.5% and 3.2% respectively. Results obtained with our genosensor were also correlated with those by RT-PCR and r(2) value found with good accuracy of 97%. The electrode was reused by dipping it into 0.1M NaOH for 3min and lost 50% of its initial activity in 4 weeks. Furthermore the technique employed for detection of HBV is EIS, which is convenient and required less analysis time.
authors.affiliation: Amity Institute of Nanotechnology, Amity University, Noida, UP, India. Electronic address: jags_biotech@yahoo.co.in.
authors.forename: Jagriti
authors.initials: J
authors.lastname: Narang
authors.affiliation: Amity Institute of Nanotechnology, Amity University, Noida, UP, India.
authors.forename: Chaitali
authors.initials: C
authors.lastname: Singhal
authors.affiliation: Holy family Hospital, Okhla, New Delhi. Electronic address: malhotra.nitesh@gmail.co.
authors.forename: Nitesh
authors.initials: N
authors.lastname: Malhotra
authors.affiliation: Oil and Natural Gas Corporation, Ankleshwar, India.
authors.forename: Sumit
authors.initials: S
authors.lastname: Narang
authors.affiliation: Amity Institute of Nanotechnology, Amity University, Noida, UP, India.
authors.forename: Anoop Krishna
authors.initials: AK
authors.lastname: Pn
authors.affiliation: Amity Institute of Nanotechnology, Amity University, Noida, UP, India.
authors.forename: Riya
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Sir Gangaram Hospital, New Delhi, India.
authors.forename: Ruby
authors.initials: R
authors.lastname: Kansal
authors.affiliation: Deptt. of Biochemistry, MD University, Rohtak, India.
authors.forename: C S
authors.initials: CS
authors.lastname: Pundir
mesh_terms: D015342:DNA Probes / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D004279:DNA, Viral / Q000032:analysis / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification; D058266:Dielectric Spectroscopy / Q000379:methods*; D017097:Electric Impedance; D055664:Electrochemical Techniques / Q000379:methods*; D006509:Hepatitis B / Q000097:blood* / Q000175:diagnosis / Q000821:virology; D006515:Hepatitis B virus / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D017641:Zeolites / Q000737:chemistry*
chemical_list: D015342:DNA Probes; D004277:DNA, Single-Stranded; D004279:DNA, Viral; D037742:Nanotubes, Carbon; D017641:Zeolites
keywords: Differential pulse voltammetry; HBV DNA; Impedimetric genosensor; PCR; Zeolites nano-crystals and multi-walled carbon nanotubes