Highly sensitive electrochemical detection of immunospecies based on combination of Fc label and PPD film/gold nanoparticle amplification.
A highly sensitive electrochemical immunoassay strategy based on the combination of ferrocene (Fc) label and poly(o-phenylenediamine) (PPD) film/gold nanoparticle (GNP) amplification for the detection of immunospecies is proposed using human IgG as the model analyte. A gold electrode is firstly modified with an electropolymerized film of poly(o-phenylenediamine), which provides a stable matrix with abundant amino-groups for the fabrication of sensing interface. Using glutaraldehyde as a cross-linker, cystamine is coupled onto the modified electrode. Subsequently, gold nanoparticle monolayer is assembled onto the resulting surface. Making use of the unique properties of gold nanoparticles, antibodies can be self-assembled onto the surface-confined gold nanoparticles via amine-Au affinity with a high loading amount and reserve high immunological activity. After the introduction of model analyte, the ferrocene (Fc)-labeled antibody is immobilized on the sensing interface by antibody-antigen specific reaction, resulting in a redox current signal. The peak current is proportional to the amount of the analyte. Under the optimized experimental conditions, the proposed sensing strategy provides a wide linear dynamic range from 25 to 1000 pg/mL with a low detection limit of 10 pg/mL. In addition, good reproducibility, high selectivity and stability are achieved. In particular, the extremely high stability of both poly(o-phenylenediamine) and gold nanoparticle monolayer allows the designed biosensing interface to withstand harsh regeneration treatment, making it reusable.
Zhang
Songbai
S
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, PR China.
Zheng
Fan
F
Wu
Zaisheng
Z
Shen
Guoli
G
Yu
Ruqin
R
D015374:Biosensing Techniques / Q000379:methods*; D004563:Electrochemistry / Q000379:methods*; D005296:Ferrous Compounds / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000379:methods*; D007074:Immunoglobulin G / Q000032:analysis; D053768:Metal Nanoparticles / Q000737:chemistry*; D000075163:Metallocenes; D010655:Phenylenediamines / Q000737:chemistry; D012680:Sensitivity and Specificity; D013997:Time Factors
D005296:Ferrous Compounds; D007074:Immunoglobulin G; D000075163:Metallocenes; D010655:Phenylenediamines; C530487:poly(o-phenylenediamine); D006046:Gold; C004998:ferrocene