title: Gold surface supported spherical liposome-gold nano-particle nano-composite for label free DNA sensing.
abstract: Immobilization of 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) liposome-gold nano-particle (DOPE-AuNP) nano-composite covalently on 3-mercaptopropionic acid (MPA) on gold surface is demonstrated for the first time for electrochemical label free DNA sensing. Spherical nature of the DOPE on the MPA monolayer is confirmed by the appearance of sigmoidal voltammetric profile, characteristic behavior of linear diffusion, for the MPA-DOPE in presence of [Fe(CN)(6)](3-/4-) and [Ru(NH(3))(6)](3+) redox probes. The DOPE liposome vesicle fusion is prevented by electroless deposition of AuNP on the hydrophilic amine head groups of the DOPE. Immobilization of single stranded DNA (ssDNA) is made via simple gold-thiol linkage for DNA hybridization sensing in the presence of [Fe(CN)(6)](3-/4-). The sensor discriminates the hybridized (complementary target hybridized), un-hybridized (non-complementary target hybridized) and single base mismatch target hybridized surfaces sensitively and selectively without signal amplification. The lowest target DNA concentration detected is 0.1×10(-12)M. Cyclic voltammetry (CV), electrochemical impedance (EIS), differential pulse voltammetry (DPV) and quartz crystal microbalance (QCM) techniques are used for DNA sensing on DOPE-AuNP nano-composite. Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM), Dynamic Light Scattering (DLS) and Ultraviolet-Visible (UV) spectroscopic techniques are used to understand the interactions between the DOPE, AuNP and ssDNA. The results indicate the presence of an intact and well defined spherical DOPE-AuNP nano-composite on the gold surface. The method could be applied for fabrication of the surface based liposome-AuNP-DNA composite for cell transfection studies at reduced reagents and costs.
authors.affiliation: Molecular Electronics Laboratory, Department of Bioelectronics and Biosensors, Alagappa University, Karaikudi 630003, India.
authors.forename: M
authors.initials: M
authors.lastname: Bhuvana
authors.forename: J Shankara
authors.initials: JS
authors.lastname: Narayanan
authors.forename: V
authors.initials: V
authors.lastname: Dharuman
authors.forename: W
authors.initials: W
authors.lastname: Teng
authors.forename: J H
authors.initials: JH
authors.lastname: Hahn
authors.forename: K
authors.initials: K
authors.lastname: Jayakumar
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D004247:DNA / Q000032:analysis* / Q000235:genetics; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006046:Gold / Q000737:chemistry*; D008081:Liposomes / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013194:Staining and Labeling; D013499:Surface Properties
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D008081:Liposomes; D010714:Phosphatidylethanolamines; D006046:Gold; D004247:DNA