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A piezoelectric immunosensor using hybrid self-assembled monolayers for detection of Schistosoma japonicum.

Wang S, Yin T, Zeng S, Che H, Yang F, Chen X, Shen G, Wu Z - PLoS ONE (2012)

Bottom Line: The correlation coefficients reached 0.973.We have developed a new, simple, sensitive, and reusable piezoelectric immunosensor that directly detects SjAb in the serum.This method may represent an alternative to the current diagnostic methods for S. japonicum infection in the clinical laboratory or for analysis outside the laboratory.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Schistosomiasis in Hunan, Department of Parasitology, Xiangya Medical College, Central South University, Changsha, China. spwang@126.com

ABSTRACT

Background: The parasite Schistosoma japonicum causes schistosomiasis disease, which threatens human life and hampers economic and social development in some Asian countries. An important lesson learned from efforts to reduce the occurrence of schistosomiasis is that the diagnostic approach must be altered as further progress is made towards the control and ultimate elimination of the disease.

Methodology/principal findings: Using mixed self-assembled monolayer membrane (mixed SAM) technology, a mixture of mercaptopropionic acid (MPA) and mercaptoethanol (ME) was self-assembled on the surface of quartz crystals by gold-sulphur-bonds. Soluble egg antigens (SEA) of S. japonicum were then cross-linked to the quartz crystal using a special coupling agent. As compared with the traditional single self-assembled monolayer immobilization method, S. japonicum antigen (SjAg) immobilization using mixed self-assembled monolayers exhibits much greater immunoreactivity. Under optimal experimental conditions, the detection range is 1:1500 to 1:60 (infected rabbit serum dilution ratios). We measured several infected rabbit serum samples with varying S. japonicum antibody (SjAb) concentrations using both immunosensor and ELISA techniques and then produced a correlation analysis. The correlation coefficients reached 0.973.

Conclusions/significance: We have developed a new, simple, sensitive, and reusable piezoelectric immunosensor that directly detects SjAb in the serum. This method may represent an alternative to the current diagnostic methods for S. japonicum infection in the clinical laboratory or for analysis outside the laboratory.

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Related in: MedlinePlus

Typical real time frequency response characteristics of the immunosensor in PBS solution.(a) NRS as negative control with PEG; (b) SjAb without PEG (dilution ratio 1∶100); (c) SjAb with PEG (dilution ratio 1∶100). Using PEG can significantly enhance the sensor response signals. Immune response-mediated frequency shift values increased from 225 Hz (b) to 343 Hz (c). The corresponding time of immune response decreased from 1600 s (b) to 1200 s (c). Considering the analysis time and reproducibility, the time for both analysis and detection of the sensors in this experiment was 1200 s.
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pone-0030779-g003: Typical real time frequency response characteristics of the immunosensor in PBS solution.(a) NRS as negative control with PEG; (b) SjAb without PEG (dilution ratio 1∶100); (c) SjAb with PEG (dilution ratio 1∶100). Using PEG can significantly enhance the sensor response signals. Immune response-mediated frequency shift values increased from 225 Hz (b) to 343 Hz (c). The corresponding time of immune response decreased from 1600 s (b) to 1200 s (c). Considering the analysis time and reproducibility, the time for both analysis and detection of the sensors in this experiment was 1200 s.

Mentions: In addition, we used polyethylene glycol (PEG) as an accelerator of the immune response. PEG reduces the interaction between antibodies (or antigens) and water molecules and increases Coulomb forces between antibodies and antigens. PEG would decrease the hydration, strengthen the electrostatic attraction, and increase the entropy by randomization of formerly orientated water of hydration expelled into the bulk phase. This method has been applied successfully for a variety of biochemical analyses [38]–[40]. The potential enhancing effect of PEG on the immune response between SjAg and SjAb was also assessed in the experiment. Figure 3 shows experimental real time frequency response characteristics of the sensor for immune responses between samples with and without PEG. NRS was used as a negative control (Figure 3a). PEG can significantly enhance the response signal of the sensor (Figure 3). The results show that the immune response-mediated frequency shift value increased from 225 Hz (Figure 3b) to 343 Hz (Figure 3c), and the corresponding time for the completion of the immune response decreased from 1600 s (Figure 3b) to 1200 s (Figure 3c). Based on these results, we chose 1200 s as the time for sensor analysis and detection in this experiment.


A piezoelectric immunosensor using hybrid self-assembled monolayers for detection of Schistosoma japonicum.

Wang S, Yin T, Zeng S, Che H, Yang F, Chen X, Shen G, Wu Z - PLoS ONE (2012)

Typical real time frequency response characteristics of the immunosensor in PBS solution.(a) NRS as negative control with PEG; (b) SjAb without PEG (dilution ratio 1∶100); (c) SjAb with PEG (dilution ratio 1∶100). Using PEG can significantly enhance the sensor response signals. Immune response-mediated frequency shift values increased from 225 Hz (b) to 343 Hz (c). The corresponding time of immune response decreased from 1600 s (b) to 1200 s (c). Considering the analysis time and reproducibility, the time for both analysis and detection of the sensors in this experiment was 1200 s.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3383785&req=5

pone-0030779-g003: Typical real time frequency response characteristics of the immunosensor in PBS solution.(a) NRS as negative control with PEG; (b) SjAb without PEG (dilution ratio 1∶100); (c) SjAb with PEG (dilution ratio 1∶100). Using PEG can significantly enhance the sensor response signals. Immune response-mediated frequency shift values increased from 225 Hz (b) to 343 Hz (c). The corresponding time of immune response decreased from 1600 s (b) to 1200 s (c). Considering the analysis time and reproducibility, the time for both analysis and detection of the sensors in this experiment was 1200 s.
Mentions: In addition, we used polyethylene glycol (PEG) as an accelerator of the immune response. PEG reduces the interaction between antibodies (or antigens) and water molecules and increases Coulomb forces between antibodies and antigens. PEG would decrease the hydration, strengthen the electrostatic attraction, and increase the entropy by randomization of formerly orientated water of hydration expelled into the bulk phase. This method has been applied successfully for a variety of biochemical analyses [38]–[40]. The potential enhancing effect of PEG on the immune response between SjAg and SjAb was also assessed in the experiment. Figure 3 shows experimental real time frequency response characteristics of the sensor for immune responses between samples with and without PEG. NRS was used as a negative control (Figure 3a). PEG can significantly enhance the response signal of the sensor (Figure 3). The results show that the immune response-mediated frequency shift value increased from 225 Hz (Figure 3b) to 343 Hz (Figure 3c), and the corresponding time for the completion of the immune response decreased from 1600 s (Figure 3b) to 1200 s (Figure 3c). Based on these results, we chose 1200 s as the time for sensor analysis and detection in this experiment.

Bottom Line: The correlation coefficients reached 0.973.We have developed a new, simple, sensitive, and reusable piezoelectric immunosensor that directly detects SjAb in the serum.This method may represent an alternative to the current diagnostic methods for S. japonicum infection in the clinical laboratory or for analysis outside the laboratory.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Schistosomiasis in Hunan, Department of Parasitology, Xiangya Medical College, Central South University, Changsha, China. spwang@126.com

ABSTRACT

Background: The parasite Schistosoma japonicum causes schistosomiasis disease, which threatens human life and hampers economic and social development in some Asian countries. An important lesson learned from efforts to reduce the occurrence of schistosomiasis is that the diagnostic approach must be altered as further progress is made towards the control and ultimate elimination of the disease.

Methodology/principal findings: Using mixed self-assembled monolayer membrane (mixed SAM) technology, a mixture of mercaptopropionic acid (MPA) and mercaptoethanol (ME) was self-assembled on the surface of quartz crystals by gold-sulphur-bonds. Soluble egg antigens (SEA) of S. japonicum were then cross-linked to the quartz crystal using a special coupling agent. As compared with the traditional single self-assembled monolayer immobilization method, S. japonicum antigen (SjAg) immobilization using mixed self-assembled monolayers exhibits much greater immunoreactivity. Under optimal experimental conditions, the detection range is 1:1500 to 1:60 (infected rabbit serum dilution ratios). We measured several infected rabbit serum samples with varying S. japonicum antibody (SjAb) concentrations using both immunosensor and ELISA techniques and then produced a correlation analysis. The correlation coefficients reached 0.973.

Conclusions/significance: We have developed a new, simple, sensitive, and reusable piezoelectric immunosensor that directly detects SjAb in the serum. This method may represent an alternative to the current diagnostic methods for S. japonicum infection in the clinical laboratory or for analysis outside the laboratory.

Show MeSH
Related in: MedlinePlus