Preparation of Functional Aptamer Films Using Layer-by-Layer Self-Assembly

Department of Chemistry, Carleton University, Ottawa-Carleton Chemistry Institute, 1125 Colonel By Drive, Ottawa, Ontario, Canada K1S 5B6.
Biomacromolecules (Impact Factor: 5.75). 05/2009; 10(5):1149-54. DOI: 10.1021/bm8014126
Source: PubMed


Advances in many aptamer-based applications will require a better understanding of how an aptamer's molecular recognition ability is affected by its incorporation into a suitable matrix. In this study, we investigated whether a model aptamer system, the sulforhodamine B aptamer, would retain its binding ability while embedded in a multilayer polyelectrolyte film. Thin films consisting of poly(diallyldimethylammonium chloride) as the polycation and both poly(sodium 4-styrene-sulfonate) and the aptamer as the polyanions were deposited by the layer-by-layer approach and were compared to films prepared using calf thymus DNA or a random single-stranded oligonucleotide. Data from UV-vis spectroscopy, quartz crystal microbalance studies, confocal microscopy, and time of flight secondary ion mass spectrometry confirm that the aptamer's recognition of its target is retained, with no loss of specificity and only a modest reduction of binding affinity, while it is incorporated within the thin film. These findings open up a raft of new opportunities for the development and application of aptamer-based functional thin films.

Download full-text


Available from: Maria C Derosa,
54 Reads
  • Source
    • "We concentrate on ultrathin polymer films on a dielectric substrate. We choose to work with polyelectrolyte films because their self-assembly as bilayers on surfaces is well understood and provides a way of producing uniform films of known thickness in a simple and reproducible manner [15]. The thickness is determined by the number of bilayers and can be controlled incrementally on a nanometer scale [16]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Controlling the interaction of an ultrafast laser pulse with a thin film remains a difficult task, especially when aiming to confine material modifications to subwavelength scales. We introduce a method to achieve reproducible submicron ablation of thin films from a dielectric surface, in a back-irradiation geometry. First, the pulse of 45-fs duration and 800-nm central wavelength nonlinearly interacts with the dielectric and undergoes strong but reproducible modifications of its intensity profile. Then, the pulse ablates a thin polymer film [four bilayers of poly(allylamine hydrochloride) and poly(sodium 4-styrene-sulfonate), 8 nm thick] from the back surface. We measure the hole with atomic force microscopy and study the influence of laser energy and focal plane position. The radius of the resulting hole is determined by a threshold intensity for ablation. Therefore, we also demonstrate how measuring the radius as a function of focal plane position provides a new approach to profiling a tightly focused laser beam under nonlinear propagation conditions. We compare the beam profile with that predicted by a widely used propagation model and show that the latter can semiquantitatively be applied to estimate the size of achievable holes.
    Physical Review Applied 09/2014; 2(3-3):034001. DOI:10.1103/PhysRevApplied.2.034001
  • Source
    Nature Nanotechnology 02/2010; 5(2):91. DOI:10.1038/nnano.2010.2 · 34.05 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Herein, we report two simple label-free electrochemical aptasensors for protein detection using layer-by-layer (LBL) self-assembled multilayers with ferrocene-appended poly(ethyleneimine) (Fc-PEI), carbon nanotubes (CNTs) and aptamer. In one sensing strategy, the Fc-PEI, CNTs and DNA aptamer are LBL assembled on the electrode surface via electrostatic interaction. In the presence of target, the aptamer on the outermost layer of the LBL self-assembled multilayer would catch the target on the electrode interface, which makes a barrier for electrons and inhibits the electro-transfer, resulting in the decreased DPV signals of Fc-PEI. Using this strategy, a wide detection range (0.3-165 ng ml(-1)) for model target thrombin is obtained, with a low detection limit of 0.14 ng ml(-1). In the similar sensing strategy for detection of lysozyme, a wide detection range (0.2 ng ml(-1) to 1.66 microg ml(-1)) and a low detection limit (0.17 ng ml(-1)) are obtained. These results prove that the LBL sensing strategies developed possess sensitivity, selectivity, stability and generality.
    Biosensors & Bioelectronics 04/2010; 25(8):1902-7. DOI:10.1016/j.bios.2010.01.003 · 6.41 Impact Factor
Show more