Fabrication of a label-free electrochemical immunosensor of low-density lipoprotein.
The silver chloride@polyaniline (PANI) core-shell nanocomposites (AgCl@PANI) combined with Au nanoparticles (AuNPs) were used to prepare the AuNPs-AgCl@PANI hybrid material. A novel sensitive label-free low-density lipoprotein (LDL) electrochemical biosensor was fabricated by adsorption of antibody to apolipoprotein B-100 (aopB-100) on an AuNPs-AgCl@PANI-modified glassy carbon (GC) electrode. The hybrid material could provide surface for high antibody loading due to its large surface-to-volume ratio. Since each LDL has an apoB-100 on its phospholipids coat, they could be bonded to the electrode surface through the specific antibody-antigen reaction. Electrochemical impedance spectroscopy (EIS) was used to characterize the recognition of LDL. The negative charges carried by LDL phospholipids coat would block the electron transfer of the [Fe(CN)6]3-/4- redox couple severely. In addition, the conductivity of LDL is very poor, so small amounts of LDL on the electrode could result in great change in the electron-transfer resistance (Ret). The biosensor exhibited a highly sensitive response to LDL with a detection limit of 0.34 pg/mL, and some factors that would affect the performance of the biosensor were studied, such as incubation time and temperature.
Yan
Wei
W
Key Laboratory of Analytical Chemistry for Life Science (MOE), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
Chen
Xiaojun
X
Li
Xinghua
X
Feng
Xiaomiao
X
Zhu
Jun-Jie
JJ
D000814:Aniline Compounds / Q000737:chemistry; D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry; D006046:Gold / Q000737:chemistry; D007118:Immunoassay / Q000379:methods*; D008077:Lipoproteins, LDL / Q000032:analysis* / Q000276:immunology*; D053768:Metal Nanoparticles / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D018030:Silver Compounds / Q000737:chemistry; D014961:X-Ray Diffraction
D000814:Aniline Compounds; D008077:Lipoproteins, LDL; D018030:Silver Compounds; C416807:polyaniline; D006046:Gold; C037548:silver chloride