Detection of cadmium by a fiber-optic biosensor based on localized surface plasmon resonance.
A novel transmission-based localized surface plasmon resonance (LSPR) fiber-optic probe has been developed to determine the heavy metal cadmium ion (Cd(II)) concentration. The LSPR sensor was constructed by immobilizing phytochelatins (PCs), (gammaGlc-Cys)(8)-Gly, onto gold nanoparticle-modified optical fiber (NM(Au)OF). The optimal immobilizing conditions of PCs on to the NM(Au)OF are 71.6mug/ml PCs in pH 7.4 PBS for 2h. The absorbability (change of light absorption) of the PC-functionalized NM(Au)OF sensor increases to 9% upon changing the Cd(II) level from 1 to 8ppb with a sensitivity of 1.24ppb(-1) and a detection limit of 0.16ppb. The sensor retained 85% of its original activity after nine cycles of deactivation and reactivations. In addition, the sensor retains its activity and gives reproducible results after storage in 5% d-(+)-trehalose dehydrate solution at 4 degrees C for 35 days. The dissociation constant (K(d)) of the immobilized PCs with Cd(II) was about 6.77x10(-8)M. In conclusion, the PCs-functionalized NM(Au)OF sensor can be used to determine the concentration of Cd(II) with high sensitivity.
Lin
Tsao-Jen
TJ
Department of Chemical Engineering, National Chung-Cheng University, 168 University Road, Min-Hsiung, Chia-Yi 621, Taiwan.
Chung
Mon-Fu
MF
D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002104:Cadmium / Q000032:analysis* / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation* / Q000379:methods; D054811:Phytochelatins / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020349:Surface Plasmon Resonance / Q000295:instrumentation* / Q000379:methods
D002104:Cadmium; D054811:Phytochelatins