Introduction of nanogold–DAB as a HRP substrate for simplifying detection in visual DNA microarrays

摘要

Tyraminesignalamplification,coupledwithagold-labelsilverstain(TSA–GLSS),hasbeendemonstratedtobeasensitivevisualassayforDNAmicroarrays.However,theprocedureislaboriousandtime-consumingasnanogoldparticlesdonotaccumulatedirectlyinthevicinityofhorseradishperoxidase(HRP).Instead,nanogoldparticlesmustaccumulatethroughtwoprocedures,includingbiotin-tyraminedepositionviaHRPcatalysisandspecificbindingofbiotinandstreptavidin,followedbytheintroductionofstreptavidin-nanogold.Theseconditionsrestrictthismethod'sutilityinDNAmicroarraydetection.Inthepresentstudy,nanogoldwascovalentlylinkedto3,3′-diaminobenzidine(DAB)toformaconjugateforthedetectionofSalmonellatyphi.DABcanbeoxidizedbyH2O2andthusaccumulatenanogold–DABviaHRPcatalysis,leadingtodirectnanogolddeposition.Theresultsindicatedthatthedetectionlimitofnanogold–DABassayreached103CFUmL?1,whichwascomparablewiththatofTSA–GLSS.Asoneincubationstepwasomittedandthesilver-stainingtimegreatlyshortened,thisnanogold–DABassaywasmoreconvenientthanTSA–GLSSandoffersgreatpotentialindetectinglowconcentrationsoftargetDNA...