Fabrication of disposable sensors for biomolecule detection using hydrazine electrocatalyst.
We have developed electrochemical DNA and protein sensors on screen-printed electrodes based on the catalytic activity of hydrazine. The sensors use carboxylic acid-functionalized conductive polymer, poly-5,2',5',2''-terthiophene-3'-carboxylic acid (polyTTCA) to make firm immobilization of dendrimer (DEN) through the covalent bond formation between the carboxylic acid groups of polymer and amine groups of dendrimer. The gold nanoparticles (AuNPs) were adsorbed on the remaining amine groups of dendrimer. The thiolated DNA probe or primary antibody was subsequently immobilized on the AuNP-covered dendrimer surfaces. Avidin-labeled hydrazine (Av-Hyd) was then immobilized on the sensor surfaces through the avidin-biotin interaction between the Av-Hyd unit and the biotinylated DNA or secondary antibody. The electrocatalytic reduction current of H(2)O(2) was measured by differential pulse voltammetry. The detection signal was amplified by the polyTTCA/DEN assembly loaded with AuNPs (approximately 3.5 nm) onto which target analyte-linked Av-Hyd was adsorbed. Linear dynamic ranges for the electrocatalytic detection of DNA and human immunoglobulin G (IgG) extending from 50 fM to 7.5 nM and from 40 fg/ml to 2.5 ng/ml, respectively, were observed along with detection limits of approximately 30 fM and 25 fg/ml, respectively. The low detection limit of the disposable sensors offers good promise for practical DNA and protein detection.
Department of Chemistry and Center for Innovative BioPhysio Sensor Technology, Pusan National University, Busan 609-735, South Korea. muhammad.shiddiky@sci.monash.edu.au
Muhammad J A
MJ
Shiddiky
Md Aminur
MA
Rahman
Chang Seung
CS
Cheol
Yoon-Bo
YB
Shim
D001360:Avidin / Q000378:metabolism; D001710:Biotin / Q000378:metabolism; D019921:Biotinylation; D002384:Catalysis; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation* / Q000379:methods*; D004247:DNA / Q000032:analysis*; D050091:Dendrimers / Q000737:chemistry; D004209:Disposable Equipment; D004563:Electrochemistry; D004566:Electrodes; D006046:Gold / Q000737:chemistry; D006801:Humans; D006834:Hydrazines / Q000737:chemistry* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000737:chemistry; D007118:Immunoassay; D053768:Metal Nanoparticles; D010084:Oxidation-Reduction; D011506:Proteins / Q000032:analysis*; D012680:Sensitivity and Specificity; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D050091:Dendrimers; D006834:Hydrazines; D011506:Proteins; D014867:Water; D001360:Avidin; D001710:Biotin; D006046:Gold; D004247:DNA; D006861:Hydrogen Peroxide