Rapid, simple, and sensitive immunoagglutination assay with SiO2 particles and quartz crystal microbalance for quantifying Schistosoma japonicum antibodies.
BACKGROUND
The resurgence of the parasitic disease schistosomiasis calls for more efficient diagnostic tests. We developed a rapid, simple, portable, and sensitive immunoagglutination assay that uses SiO(2) particles and quartz crystal microbalance (QCM) for quantifying Schistosoma japonicum (Sj) antibodies (SjAb).


METHODS
We prepared submicrometer-sized silica particles derivatized with Sj antigens as replacements for traditional latex microspheres to specifically agglutinate in the presence of SjAb targets, and we used the QCM monitor to measure the resulting frequency shifts. We optimized the assay medium by adding poly(ethylene glycol) (PEG) as a response accelerator of immunoagglutination. To minimize or eliminate any nonspecific agglutination or adsorption interferences, we conducted appropriate sealing procedures separately for silica particles and the QCM probe.


RESULTS
The measured frequency changes were linearly related to the SjAb concentrations in infected rabbit serum. The PEG-assisted immunoagglutination system was quantitatively sensitive to SjAb concentrations ranging from approximately 0.70 to 32.31 mg/L, with a detection limit of approximately 0.46 mg/L. The obtained linear regression equation was: y=43.61 x+80.44 (r=0.9872). Several serum specimens were evaluated with the developed QCM immunoassay and the results were compared with ELISA, validating the feasibility of practical applications.


CONCLUSIONS
This novel immunoagglutination-based QCM detection format is rapid, simple to use, and more portable than conventional diagnostic immunoassays, thus offering a promising alternative tool that can be used for point-of-care clinical diagnosis of schistosomiasis, particularly in epidemic situations.
Wang
Hua
H
State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, P.R. China. huawang@hnu.cn
Zhang
Yun
Y
Yan
Bani
B
Liu
Li
L
Wang
Shiping
S
Shen
Guoli
G
Yu
Ruqin
R
D000372:Agglutination Tests / Q000295:instrumentation* / Q000379:methods*; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000737:chemistry / Q000276:immunology; D002138:Calibration; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008863:Microspheres; D011791:Quartz; D015203:Reproducibility of Results; D012549:Schistosoma japonicum / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000097:blood* / Q000276:immunology; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D013997:Time Factors
D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D011791:Quartz; D012822:Silicon Dioxide