clarly indicates the concentration changes of AuNPs and AuNPs-HSA conjugate after the addition of HSA (1.8-70.3 nM).It is found that the concentrations of AuNPs and AuNPs-HSA conjugate are linearly related to the concentration of HSA added (1.8-28.1 nM).with equations of cAuNPs(nM) = -0.082cHSA(nM)+2.81(r=0.996)and cAuNPs-HSA(nM)=0.082cHSA(nM)+0.14(r=0.996).Limits of detection with a signal-to-noise ratio(S/N)of 3 for both AuNPs and AuNPs-HSA conjugate calibrations are o.8 nM.which were well comparable or superior to those achieved by sensitive fluorometric methods