title: A novel immobilization strategy for electrochemical detection of cancer biomarkers: DNA-directed immobilization of aptamer sensors for sensitive detection of prostate specific antigens.
abstract: We report on a novel strategy for DNA aptamer immobilization to develop sensitive electrochemical detection of a protein biomarker, with prostate specific antigen (PSA) as a case biomarker. Thiolated single-stranded DNA (ssDNA) was co-immobilized with 3-mercapto-1-propanol on gold electrodes, and used as a scaffold for DNA aptamer attachment through hybridization of the aptamer overhang (so-called "DNA-directed immobilization aptamer sensors", DDIAS). In the approach, the complementary DNA aptamer against PSA was assembled by the probe ssDNA onto the electrode to detect PSA; or the probe ssDNA directly hybridized with a complementary DNA aptamer/PSA complex following their pre-incubation in solution, so-called 'on-chip' and 'in-solution' methods, respectively. A double stranded DNA intercalator with a ferrocenyl (Fc) redox marker was synthesized to evaluate the feasibility of the strategy. The results demonstrate that the 'in-solution' method offers a favourable medium (in a homogeneous solution) for the binding between the aptamer and PSA, which shows to be more efficient than the 'on-chip' approach. DDIAS shows promising analytical performance under optimized conditions, with a limit of detection in the range of fM and low non-specific adsorption.
authors.affiliation: Department of Chemistry, University of Bath, Claverton Down, BA2 7AY, Bath, UK. z.yang@bath.ac.uk c.g.frost@bath.ac.uk.
authors.forename: Zhugen
authors.initials: Z
authors.lastname: Yang
authors.forename: Barbara
authors.initials: B
authors.lastname: Kasprzyk-Hordern
authors.forename: Sean
authors.initials: S
authors.lastname: Goggins
authors.forename: Christopher G
authors.initials: CG
authors.lastname: Frost
authors.forename: Pedro
authors.initials: P
authors.lastname: Estrela
mesh_terms: D000818:Animals; D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000032:analysis* / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D004277:DNA, Single-Stranded / Q000737:chemistry*; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D061925:Immobilized Nucleic Acids / Q000737:chemistry*; D057230:Limit of Detection; D020005:Propanols / Q000737:chemistry; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry
chemical_list: C518434:3-mercaptopropanol; D052157:Aptamers, Nucleotide; D014408:Biomarkers, Tumor; D004277:DNA, Single-Stranded; D061925:Immobilized Nucleic Acids; D020005:Propanols; D013438:Sulfhydryl Compounds; D006046:Gold; D017430:Prostate-Specific Antigen