title: Quantum dot monolayer for surface plasmon resonance signal enhancement and DNA hybridization detection.
abstract: We report results of studies relating to the fabrication of a surface plasmon resonance (SPR)-based nucleic acid sensor for quantification of DNA sequence specific to chronic myelogeneous leukemia (CML). The SPR disk surface has been modified with octadecanethiol self-assembled monolayer followed by deposition of the tri-n-octylphosphine oxide capped cadmium selenide quantum dots (QD) Langmuir monolayer. The deposition is performed via Langmuir-Blodgett (LB) technique. For the sensor chip preparation, covalent immobilization of the thiol-terminated DNA probe sequence (pDNA) using displacement reaction is accomplished. This integrated SPR chip has been used to detect target complementary DNA concentration by monitoring the change in coupling angle via hybridization. It is revealed that this biosensor exhibits high sensitivity (0.7859 m(0)pM(-1)) towards complementary DNA and can be used to detect it in the concentration range, 180 pM to 5 pM with detection limit as 4.21 pM. The results of kinetic studies yield the values of hybridization and dissociation rate constants as 9.6 × 10(4) M(-1) s(-1) and 2.3 × 10(-2) s(-1), respectively, with the equilibrium constant for hybridization as 4.2 × 10(6) M(-1).
authors.affiliation: The Northcap University (Formerly ITM University), Gurgaon 122017, India.
authors.forename: Aditya Sharma
authors.initials: AS
authors.lastname: Ghrera
authors.affiliation: The DST Centre on Biomolecular Electronics, CSIR-National Physical Laboratory, Dr K S Krishnan Marg, New Delhi 110012, India.
authors.forename: Manoj Kumar
authors.initials: MK
authors.lastname: Pandey
authors.affiliation: The DST Centre on Biomolecular Electronics, CSIR-National Physical Laboratory, Dr K S Krishnan Marg, New Delhi 110012, India; Department of Biotechnology, Delhi Technological University, Delhi 110042, India. Electronic address: bansi.malhotra@gmail.com.
authors.forename: Bansi Dhar
authors.initials: BD
authors.lastname: Malhotra
mesh_terms: D015374:Biosensing Techniques; D015342:DNA Probes / Q000737:chemistry / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics / Q000302:isolation & purification*; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000175:diagnosis* / Q000235:genetics; D009693:Nucleic Acid Hybridization; D020411:Oligonucleotide Array Sequence Analysis; D045663:Quantum Dots / Q000737:chemistry; D020349:Surface Plasmon Resonance
chemical_list: D015342:DNA Probes; D004273:DNA, Neoplasm
keywords: Biosensor; Cadmium selenide; Chronic myelogenous leukemia; Langmuir–Blodgett; Nucleic acid hybridization; Quantum dots; Surface plasmon resonance