Label-Free DNA Biosensor for Electrochemical Detection of Short DNA Sequences Related to Human Papilloma Virus

Abstract

Highly sensitive label-free techniques of DNA determination are particularly interesting in relation to the present development of an electrochemical hybridization biosensor for the detection of short DNA fragments specific to the human papilloma virus (HPV). Unlabeled DNA probes have been immobilized by spontaneous coadsorption of thiolated single-stranded oligonucleotides (HS-ssDNA) onto the sensing surface of a screen-printed gold electrode (SPGE). The covalently immobilized single-stranded DNA probe (HS-ssDNA) could selectively hybridize with its complementary DNA (cDNA) in solution to form double-stranded DNA (dsDNA) on the surface. DNA is treated with acid (e.g., 0.5 M chloridric acid), and the acid-released purine bases are directly determined by square wave voltammetry (SWV).Variables of the probe-immobilization and hybridization steps are optimized to offer convenient quantitation of HPV DNA target, in connection with a short hybridization time. Peak currents were found to increase in the following order: hybrid-modified SPGE, 11-base mismatched modified SPGE, 18-base mismatched SPGE, and the probe modified SPGE. Control experiments with noncomplementary oligonucleotides were carried out to assess whether the suggested DNA sensor responds selectively to the target. The effect of the target DNA concentration on the hybridization signal was also studied. Under optimal conditions, this sensor has a good calibration range with HPV DNA sequence detection limit of 2 pg Á ml À1 (S=N ¼ 3).

An ultrasensitive electrochemical DNA biosensor based on graphene/Au nanorod/polythionine for human papillomavirus DNA detection

“…93%-100% of worldwide invasive carcinomas have been shown to be associated with a limited spectrum of HPV types, mostly HPV 16 and 18 (Zari et al, 2009). The detection of DNA sequences is of central importance to the virus and genetic detection, and early diagnosis of diseases (Wang et al, 2011a;Lu et al, 2009).…”

Application of Factorial Design Experiments to the Development of a Disposable Amperometric DNA Biosensor

“…For times of 15, 30, 60 and 120 minutes, there was coverage of about 38 %, 19 %, 29 % and 40 %, respectively (data not shown). Evaluation of the stability of the SAM by successive scans (ten cycles) in K 4 Fe(CN) 6 solution showed that the SAM formed after 120 minutes was the most stable, with minimal loss of coating. For the other formation times there was a decrease of the SAM at the third cycle.…”

“…The analysis of the percentage of SAM on the CDtrode surfaces was performed by calculating the oxidation peak area of K 4 Fe(CN) 6 , before and after modification with lipoic acid. For times of 15, 30, 60 and 120 minutes, there was coverage of about 38 %, 19 %, 29 % and 40 %, respectively (data not shown).…”

Nanoscale virus biosensors: state of the art

“…After hybridization, DNA is treated with an acid, and the acid-released purine bases are directly determined by SWV with HPV sequence detection limit of 2 pg·mL −1 (S/N =3). 100 The specific sequence for hepatitis C virus-1 (HCV-1) was detected by Pournaghi-Azar et al, 101 using a label-free DNA hybridization biosensor. The sensor relied on the immobilization of a 20-mer oligonucleotide (containing 2 guanines and 11 cytosines) as a probe on the pencil graphite electrode.…”