title: Highly sensitive and reversible silicon nanowire biosensor to study nuclear hormone receptor protein and response element DNA interactions.
abstract: To thoroughly understand the role that estrogen receptors partake in regulation of gene expression, characterization of estrogen receptors (ERs) and estrogen-response elements (EREs) interactions is essential. In the work, we present a highly sensitive and reusable silicon nanowire (SiNW) biosensor to study the interactions between human ER proteins (ER, α and β subtypes) and EREs (dsDNA). The proteins were covalently immobilized on the SiNW surface. Various EREs including wild-type, mutant and scrambled DNA sequences were then applied to the protein-functionalized SiNW surface. Due to negatively charged dsDNA, binding of the EREs to the ERs on the n-type SiNW biosensor leads to the accumulation of negative charges on the surface, thereby inducing increase in resistance. The results show that the specificity of the ERE-ERα binding is higher than that of the ERE-ERβ binding, what is more, the mutant ERE reduces the binding affinity for both ERα and ERβ. By applying various concentrations of wild-type ERE to the bound ERα, a very low concentration of 10 fM wild-type ERE was found to be able to bind to the ERα. The reversible association and dissociation between ERα and wt-ERE was achieved, pointing to a reusable biosensor for protein-DNA binding. Through the study, we have established the SiNW biosensor as a promising method in providing comprehensive study for hormone receptor-response element interactions.
authors.affiliation: Institute of Microelectronics, A*STAR (Agency for Science, Technology and Research), 11 Science Park Road, Singapore Science Park II, Singapore 117685, Singapore. zhanggj@ime.a-star.edu.sg
authors.forename: Guo-Jun
authors.initials: GJ
authors.lastname: Zhang
authors.forename: Min Joon
authors.initials: MJ
authors.lastname: Huang
authors.forename: Zhan Hong Henry
authors.initials: ZH
authors.lastname: Luo
authors.forename: Guang Kai Ignatius
authors.initials: GK
authors.lastname: Tay
authors.forename: Eu-Jin Andy
authors.initials: EJ
authors.lastname: Lim
authors.forename: Edison T
authors.initials: ET
authors.lastname: Liu
authors.forename: Jane S
authors.initials: JS
authors.lastname: Thomsen
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003217:Conductometry / Q000295:instrumentation*; D004247:DNA / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D017743:Equipment Reuse; D036103:Nanotechnology / Q000295:instrumentation; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure; D025941:Protein Interaction Mapping / Q000295:instrumentation*; D011960:Receptors, Estrogen / Q000737:chemistry*; D020218:Response Elements; D012680:Sensitivity and Specificity; D012825:Silicon / Q000737:chemistry*
chemical_list: D011960:Receptors, Estrogen; D004247:DNA; D012825:Silicon