title: Elucidation of the effect of aptamer immobilization strategies on the interaction between cell and its aptamer using atomic force spectroscopy.
abstract: The immobilization strategy of cell-specific aptamers is of great importance for studying the interaction between a cell and its aptamer. However, because of the difficulty of studying living cell, there have not been any systematic reports about the effect of immobilization strategies on the binding ability of an immobilized aptamer to its target cell. Because atomic force spectroscopy (AFM) could not only be suitable for the investigation of living cell under physiological conditions but also obtains information reflecting the intrinsic properties of individuals, the effect of immobilization strategies on the interaction of aptamer/human hepatocarcinoma cell Bel-7404 was successively evaluated using AFM here. Two different immobilization methods, including polyethylene glycol immobilization method and glutaraldehyde immobilization method were used, and the factors, such as aptamer orientation, oligodeoxythymidine spacers and dodecyl spacers, were investigated. Binding events measured by AFM showed that a similar unbinding force was obtained regardless of the change of the aptamer orientation, the immobilization method, and spacers, implying that the biophysical characteristics of the aptamer at the molecular level remain undisturbed. However, it showed that the immobilization orientation, immobilization method, and spacers could alter the binding probability of aptamer/Bel-7404 cell. Presumably, these factors may affect the accessibility of the aptamer toward its target cell. These results may provide valuable information for aptamer sensor platforms including ultrasensitive biosensor design.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Bianxia
authors.initials: B
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Kemin
authors.initials: K
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Du
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province, Hunan University, Changsha, 410082, China.
authors.forename: Zhiping
authors.initials: Z
authors.lastname: Li
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry / Q000378:metabolism*; D015374:Biosensing Techniques / Q000379:methods; D045744:Cell Line, Tumor; D005976:Glutaral / Q000737:chemistry*; D006801:Humans; D018625:Microscopy, Atomic Force; D011092:Polyethylene Glycols / Q000737:chemistry*; D011485:Protein Binding; D013499:Surface Properties
chemical_list: D052157:Aptamers, Nucleotide; D011092:Polyethylene Glycols; D005976:Glutaral
keywords: aptamer orientation; dodecyl spacers; oligo(dT) spacers; single-molecule force spectroscopy