title: A label-free electrochemical biosensor based on a DNA aptamer against codeine.
abstract: In order to develop a sensor for opium alkaloid codeine detection, DNA aptamers against codeine were generated by SELEX (systematic evolution of ligands by exponential enrichment) technique. An aptamer HL7-14, which is a 37-mer sequence with Kd values of 0.91 μM, was optimized by the truncation-mutation assay. The specificity investigation shows that HL7-14 exhibits high specificity to codeine over morphine, and almost cannot bind to other small molecule. With this new selected aptamer, a novel electrochemical label-free codeine aptamer biosensor based on Au-mesoporous silica nanoparticles (Au-MSN) as immobilized substrate has been proposed using [Fe(CN)6](3-/4-) as electroactive redox probe. The linear range covered from 10 pM to 100 nM with correlation coefficient of 0.9979 and the detection limit was 3 pM. Our study demonstrates that the biosensor has good specificity, stability and well regeneration. It can be used to detect codeine.
authors.affiliation: Chemistry and Chemical Engineering College, Yunnan Normal University, Kunming 650092, China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Huang
authors.forename: Xiaojuan
authors.initials: X
authors.lastname: Yang
authors.forename: Cui
authors.initials: C
authors.lastname: Qi
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Niu
authors.forename: Chunling
authors.initials: C
authors.lastname: Zhao
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Zhao
authors.forename: Dihua
authors.initials: D
authors.lastname: Shangguan
authors.forename: Yunhui
authors.initials: Y
authors.lastname: Yang
mesh_terms: D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods*; D003061:Codeine / Q000032:analysis*; D055664:Electrochemical Techniques / Q000379:methods; D011485:Protein Binding / Q000502:physiology; D052156:SELEX Aptamer Technique / Q000379:methods*
chemical_list: D052157:Aptamers, Nucleotide; D003061:Codeine
keywords: Aptamer; Au-mesoporous silica nanoparticles; Codeine; Electrochemical aptasensor; Systematic evolution of ligands by exponential enrichment