Sensitivity enhancement of a dynamic mode microcantilever by stress inducer and mass inducer to detect PSA at low picogram levels.
We report two types of signal enhancement strategy derived from the origin of mechanical response, surface stress and mass, of the dynamic mode microcantilever for the detection of PSA at low picogram scales (low femtomolar concentration). The PSA detection at extremely low concentration levels is crucial to the early detection of relapses of prostate cancer after the radical prostatectomy and the detection of breast cancer in patient's serum. There is a clear need for the ultrasensitive detection of PSA via simple and rapid diagnostic tools. From the motives, to increase the sensitivity of the microcantilever, PSA polyclonal antibody (PSA pAb) as an additional surface stress inducer and PSA polyclonal antibody-conjugated silica nanoparticles (pAb-SiNPs) as a mass inducer have been applied to the PSA-captured microcantilevers. From two types of sandwich assay, we could confirm the sensitivity enhancement effects (2 approximately 4 times enhanced at the same concentrations) enough to detect PSA at low picogram levels (LOD of 1 pg/mL or below). Moreover, surface stress due to steric interactions between epitope-specific monoclonal antibodies was assessed to support a signal amplification strategy by stress inducer, and the reduction of signal enhancement due to stiffness increase by the mass inducer was studied to clarify the sensitivity enhancement of the microcantilever by mass inducer.
Lee
Sang-Myung
SM
Nano-Bio Research Center, Korea Institute of Science and Technology, 39-1, Haweolgog-Dong, Seongbuk-Gu, Seoul, 136-791, Republic of Korea.
Hwang
Kyo Seon
KS
Yoon
Hyo-Jin
HJ
Yoon
Dae Sung
DS
Kim
Sang Kyung
SK
Lee
Yoon-Sik
YS
Kim
Tae Song
TS
D000911:Antibodies, Monoclonal / Q000737:chemistry; D004574:Electromagnetic Fields; D006801:Humans; D008297:Male; D053758:Nanoparticles; D036103:Nanotechnology; D017430:Prostate-Specific Antigen / Q000032:analysis*; D011468:Prostatectomy; D012822:Silicon Dioxide; D013314:Stress, Mechanical; D013499:Surface Properties
D000911:Antibodies, Monoclonal; D012822:Silicon Dioxide; D017430:Prostate-Specific Antigen