Gold nanoparticle based immunochromatography using a resin modified micropipette tip for rapid and simple detection of human chorionic gonadotropin hormone and prostate-specific antigen

Abstract

A novel bioanalysis system based on immunochromatography was developed in connection with a nitrocellulose resin-modified micropipette tip, namely as ZipTip w . The sandwich-type immunoassay was applied to our bioananalysis system. The first antibodies that were aspirated by the micropipette were immobilized on the immunochromatographic resin at the edge of micropipette tip. The blocking solution was also aspirated in the same fashion. The measurement operation was performed by aspirating the sample solution, and then the gold colloidal nanoparticles (Au naps) conjugated secondary antibody solution. Since this bioanalysis system utilizes a micropipette, it is possible to increase the sample volume, which would enable the detection of antigen at low concentrations. In addition, the washing procedure can also be performed easily to reduce the background level. After the antigen-antibody reaction, the color intensity of Au naps could be observed by the naked eye. For analytical evaluation, the color intensity was captured by a scanner, and processed by analysis software. We have achieved the detection of human chorionic gonadotropin hormone (hCG) and total prostate-specific antigen (TPSA), which are well-known as fundamental indicators of pregnancy and cancer. The limit of detection (LOD) for hCG was 8 ng/ml (0.8 ng/tip), which is comparable to that of other conventional systems based on immunochromatography. Moreover, the LOD for TPSA was improved over the existing systems with the application of different sample volumes, such as 5 ng/ml (1 ng/tip) in 200 ml sample volume, and 2 ng/ml (0.6 ng/tip) in 300 ml sample volume. Since our bioanalysis system requires a small amount of immobilized antigen, it would be greatly useful in basic research for screening the antigen-antibody reactions. Besides, our bioanalysis system can be applied to on-field screening, since its operation is simple, and the visual results can be obtained rapidly. q

Control of Tumor Markers Using Nanotechnology

“…An immunochromatographic SPR test has been reported for the determination of hCG, which is based on the immobilization of primary antibodies in a thin zone of the chromatographic support, in which the analyte is accumulated, and the conjugation of the secondary antibodies with AuNPs [63]. Other similar immunochromatographic tests for PSA and hCG determination involve the measurement of the intense red color owing to the accumulation of the AuNPs [64][65][66].…”

“…In some instances, these NPs are only used as nanoscaffolds to improve the immobilization of the antibodies [19,20,84], although other methods involve the measurement of a property of the AuNPs, which is correlated with the analyte concentration, such as SPR [63], light scattering [48,49] and color intensity image [64][65][66]. The lowest LOD reported corresponds to a sandwich assay using this last detection system [65].…”

Fabrication of Heteronanorod Structures by Dynamic Shadowing Growth

“…Au/Si NANOROD FOR VIRUS DETECTION Nanotechnology-based biosensors have been applied in protein and virus detection in the way of surface-enhanced Raman spectroscopy (SERS) [48], metal enhanced fluorescence (MEF) [49], quantum dots [50], induced color change by gold nanoparticles [51], [52], and antibody conjugated fluorescent nanoparticles [53]- [55]. All the nanostructures used for biosensing applications have two characteristics: first, they contain certain recognition mechanisms specified to the analyte, for example, antibodies or enzymes for bio-agents; second, they are able to generate a distinguished signal from the analyte.…”

Highly sensitive chemiluminescence immunoassay on chitosan membrane modified paper platform using TiO2 nanoparticles/multiwalled carbon nanotubes as label

“…It has been used as a premier oncological marker for prostate cancer in male serum and monitoring the level of PSA is so far the most commonly used approach. Previous methods established for PSA detection include the electrochemical, piezoelectric, fluorescence, surface plasmon resonance, chromatography and surface enhanced Raman scattering techniques . Though these methods have distinct advantages, some of them have their own limitations such as poor sensitivity and high equipment cost.…”