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author:("Tsai, haiyan")
1.  Detection of rabbit IgG by using functional magnetic particles and an enzyme-conjugated antibody with a homemade magnetic microplate 
Background
The enzyme-linked immunosorbent assay (ELISA) has been used for diagnosing medical and plant pathologies. In addition, it is used for quality-control evaluations in various industries. The ELISA is the simplest method for obtaining excellent results; however, it is time consuming because the immunoreagents interact only on the contact surfaces. Antibody-labeled magnetic particles can be dispersed in a solution to yield a pseudohomogeneous reaction with antigens which improved the efficiency of immunoreaction, and can be easily separated from the unreactive substances by applying a magnetic force. We used a homemade magnetic microplate, functional magnetic particles (MPs) and enzyme-labeled secondary antibody to perform the sandwich ELISA successfully.
Results
Using antibody-labeled MPs enabled reducing the analysis time to one-third of that required in using a conventional ELISA. The secondary antibody conjugated with horseradish peroxidase (HRP) was affinity-bound to the analyte (IgG in this study). The calibration curve was established according to the measured absorbance of the 3, 3′, 5, 5′-tetramethybezidine–HRP reaction products versus the concentrations of standard IgG. The linear range of IgG detection was 114 ng/mL–3.5 ng/mL. The limit of detection (LOD) of IgG was 3.4 ng/mL. The recovery and coefficient of variation were 100% (±7%) and 116% (±4%) for the spiked concentrations of 56.8 ng/mL and 14.2 ng/mL, respectively.
Conclusion
Pseudohomogeneous reactions can be performed using functional MPs and a magnetic microplate. Using antibody-labeled MPs, the analysis time can be reduced to one-third of that required in using a conventional ELISA. The substrate–enzyme reaction products can be easily transferred to another microplate, and their absorbance can be measured without interference by light scattering caused by magnetic microbeads. This method demonstrates great potential for detecting other biomarkers and in biochemical applications.
Graphical AbstractA magnetic ELISA with convenient magnetic microplate.
Electronic supplementary material
The online version of this article (doi:10.1186/s13065-015-0088-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s13065-015-0088-1
PMCID: PMC4350001  PMID: 25745512
Immunoassay; Functional magnetic particles; Magnetic separator
2.  Detection of rabbit IgG by using functional magnetic particles and an enzyme-conjugated antibody with a homemade magnetic microplate 
Background
The enzyme-linked immunosorbent assay (ELISA) has been used for diagnosing medical and plant pathologies. In addition, it is used for quality-control evaluations in various industries. The ELISA is the simplest method for obtaining excellent results; however, it is time consuming because the immunoreagents interact only on the contact surfaces. Antibody-labeled magnetic particles can be dispersed in a solution to yield a pseudohomogeneous reaction with antigens which improved the efficiency of immunoreaction, and can be easily separated from the unreactive substances by applying a magnetic force. We used a homemade magnetic microplate, functional magnetic particles (MPs) and enzyme-labeled secondary antibody to perform the sandwich ELISA successfully.
Results
Using antibody-labeled MPs enabled reducing the analysis time to one-third of that required in using a conventional ELISA. The secondary antibody conjugated with horseradish peroxidase (HRP) was affinity-bound to the analyte (IgG in this study). The calibration curve was established according to the measured absorbance of the 3, 3′, 5, 5′-tetramethybezidine–HRP reaction products versus the concentrations of standard IgG. The linear range of IgG detection was 114 ng/mL–3.5 ng/mL. The limit of detection (LOD) of IgG was 3.4 ng/mL. The recovery and coefficient of variation were 100% (±7%) and 116% (±4%) for the spiked concentrations of 56.8 ng/mL and 14.2 ng/mL, respectively.
Conclusion
Pseudohomogeneous reactions can be performed using functional MPs and a magnetic microplate. Using antibody-labeled MPs, the analysis time can be reduced to one-third of that required in using a conventional ELISA. The substrate–enzyme reaction products can be easily transferred to another microplate, and their absorbance can be measured without interference by light scattering caused by magnetic microbeads. This method demonstrates great potential for detecting other biomarkers and in biochemical applications.
Graphical AbstractA magnetic ELISA with convenient magnetic microplate.
Electronic supplementary material
The online version of this article (doi:10.1186/s13065-015-0088-1) contains supplementary material, which is available to authorized users.
doi:10.1186/s13065-015-0088-1
PMCID: PMC4350001  PMID: 25745512
Immunoassay; Functional magnetic particles; Magnetic separator
3.  Bioactivity comparison of extracts from various parts of common and tartary buckwheats: evaluation of the antioxidant- and angiotensin-converting enzyme inhibitory activities 
Background
Buckwheat flour and buckwheat sprouts possess antioxidant properties, and previous studies have reported on buckwheat flour displaying an inhibitory activity for angiotensin-I converting enzyme (ACE). Information is lacking on the bioactivity of other parts of the buckwheat, such as the seed hulls and plant stalks. This study investigates the ACE inhibitory activity and antioxidant activity of various parts of 2 types of buckwheat, namely, common buckwheat (Fagopyrum esculentum Moench) and tartary buckwheat (Fagopyrum tataricum Gaertn).
Results
The extract of common hulls extracted using 50% (v/v)-ethanol solvent presented a remarkable inhibitory activity. The value of IC50 is 30 μg ml-1. The extracts of both common and tartary hulls extracted using 50% (v/v)-ethanol solvent demonstrated an antioxidant activity that is superior to that of other extracts.
Conclusion
This study determined that the ethanolic extract of the hulls of common buckwheat presented more favorable antioxidant and ACE inhibitory abilities. However, the correlation of antioxidant activity and ACE inhibitory activity for all 18 types of extracts is low. The ACE inhibitory activity could have been caused by a synergistic effect of flavonoids or from other unidentified components in the extracts. The ethanolic extract of common hulls demonstrated remarkable ACE inhibitory activity and is worthy of further animal study.
doi:10.1186/1752-153X-6-78
PMCID: PMC3485629  PMID: 22853321
Tartary buckwheat; Common buckwheat; ACE inhibition; Microplate fluometric assay
4.  Analytical and preparative applications of magnetic split-flow thin fractionation on several ion-labeled red blood cells 
Background
Magnetic Split-flow thin (SPLITT) fractionation is a newly developed technique for separating magnetically susceptible particles. Particles with different field-induced velocities can be separated into two fractions by adjusting applied magnetic forces and flow-rates at inlets and outlets.
Methods
Magnetic particles, Dynabeads, were used to test this new approach of field-induced velocity for susceptibility determination using magnetic SF at different magnetic field intensities. Reference measurements of magnetic susceptibility were made using a superconducting quantum interference device (SQUID) magnetometer. Various ion-labeled red blood cells (RBC) were used to study susceptibility determination and throughput parameters for analytical and preparative applications of magnetic SPLITT fractionation (SF), respectively. Throughputs were studied at different sample concentrations, magnetic field intensities, and channel flow-rates.
Results
The susceptibilities of Dynabeads determined by SPLITT fractionation (SF) were consistent with those of reference measurement using a superconducting quantum interference device (SQUID) magnetometer. Determined susceptibilities of ion-labeled RBC were consistent within 9.6% variations at two magnetic intensities and different flow-rates. The determined susceptibilities differed by 10% from referenced measurements. The minimum difference in magnetic susceptibility required for complete separation was about 5.0 × 10-6 [cgs]. Sample recoveries were higher than 92%. The throughput of magnetic SF was approximately 1.8 g/h using our experimental setup.
Conclusion
Magnetic SF can provide simple and economical determination of particle susceptibility. This technique also has great potential for cell separation and related analysis. Continuous separations of ion-labeled RBC using magnetic SF were successful over 4 hours. The throughput was increased by 18 folds versus early study. Sample recoveries were 93.1 ± 1.8% in triplicate experiments.
doi:10.1186/1477-044X-4-6
PMCID: PMC1779266  PMID: 17177988

Results 1-4 (4)