title: Sensitive bifunctional aptamer-based electrochemical biosensor for small molecules and protein.
abstract: In this paper, a bifunctional electrochemical biosensor for highly sensitive detection of small molecule (adenosine) or protein (lysozyme) was developed. Two aptamer units for adenosine and lysozyme were immobilized on the gold electrode by the formation of DNA/DNA duplex. The detection of adenosine or lysozyme could be carried out by virtue of switching structures of aptamers from DNA/DNA duplex to DNA/target complex. The change of the interfacial feature of the electrode was characterized by cyclic voltammertic (CV) response of surface-bound [Ru(NH(3))(6)](3+). On the other hand, DNA functionalized Au nanoparticles (DNA-AuNPs) were used to enhance the sensitivity of the aptasensor because DNA-AuNPs modified interface could load more [Ru(NH(3))(6)](3+) cations. Thus, the assembly of two aptamer-contained DNA strands integrated with the DNA-AuNPs amplification not only improves the sensitivity of the electrochemical aptasensor but also presents a simple and general model for bifunctional aptasensor. The proposed aptasensor has low detection limit (0.02 nM for adenosine and 0.01 microg mL(-1) for lysozyme) and exhibits several advantages such as high sensitivity and bifunctional recognition.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China.
authors.forename: Chunyan
authors.initials: C
authors.lastname: Deng
authors.forename: Jinhua
authors.initials: J
authors.lastname: Chen
authors.forename: Lihua
authors.initials: L
authors.lastname: Nie
authors.forename: Zhou
authors.initials: Z
authors.lastname: Nie
authors.forename: Shouzhuo
authors.initials: S
authors.lastname: Yao
mesh_terms: D000241:Adenosine / Q000032:analysis*; D052157:Aptamers, Nucleotide / Q000737:chemistry*; D015374:Biosensing Techniques; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry; D009113:Muramidase / Q000032:analysis* / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry; D012680:Sensitivity and Specificity; D013499:Surface Properties
chemical_list: D052157:Aptamers, Nucleotide; D009942:Organometallic Compounds; D006046:Gold; D009113:Muramidase; D000241:Adenosine