Reusable immunomagnetic beads in an enzyme immunoassay

Han, Feng; Luo, Jin; Guo, Haipeng; Zhang, W. H.; He, Dong; Yan, Xue-Qian

doi:10.1007/s11274-006-9262-x

Cited by 4 publications

(3 citation statements)

References 12 publications

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“…Immobilization of RBP4 was performed using tosyl-activated magnetic beads (Dynabeads M-280, Dynal Biotech, Norway). The coating process involves the covalent coupling of the p -toluenesulphonyl (tosyl) groups on the surface of the magnetic beads with the primary amino groups (NH 2 ) of the proteins. , The magnetic beads were washed three times with coupling buffer (0.1 M borate buffer, pH 9.5) and separated by magnetic separation on a magnetic stand (Dynal, Norway). For immobilization, 0.1 mg of human RBP4 was dissolved in the coupling buffer and mixed with the same buffer containing 3 × 10 8 magnetic beads.…”

Section: Methodsmentioning

confidence: 99%

ssDNA Aptamer-Based Surface Plasmon Resonance Biosensor for the Detection of Retinol Binding Protein 4 for the Early Diagnosis of Type 2 Diabetes

et al. 2008

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Retinol binding protein 4 (RBP4) is a useful biomarker in the diagnosis of type 2 diabetes since its level in the serum is higher in insulin-resistant states. Accurate measurement of the serum RBP4 levels is hampered by conventional immunologic methods, such as enzyme-linked immunosorbent assay (ELISA). In this study, therefore, we have developed an aptamer-based surface plasmon resonance (SPR) biosensor that can be used to sense for RBP4 in serum samples. A single-stranded DNA (ssDNA) aptamer that showed high affinity (Kd = 0.2 +/- 0.03 microM) and specificity to RBP4 was selected. This RBP4-specific aptamer was immobilized on a gold chip and used in a label-free RBP4 detection using SPR. Analysis of RBP4 in artificial serum using SPR was compared with ELISA and Western blot analysis. Our results indicated that the RBP4-specific aptamer-based SPR biosensor gave better dose-dependent responses and was more sensitive than ELISA assays. As such, this RBP4 aptamer-based SPR biosensor can be potentially used to monitor the RBP4 levels within the serum as an indicator of type 2 diabetes.

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Section: Methodsmentioning

confidence: 99%

ssDNA Aptamer-Based Surface Plasmon Resonance Biosensor for the Detection of Retinol Binding Protein 4 for the Early Diagnosis of Type 2 Diabetes

et al. 2008

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“…The coating efficiency of IMBs was expressed as ratio of the amount of pAbs bound on MBs to the total amount of pAbs. 19 Determination of binding efficiency of IMBs.-The binding efficiencies of IMBs that were conjugated with antibody on carboxylic acid-terminated silica MBs (CSMs, Bioclone Inc., San Diego, CA, USA) or carboxylic acid-terminated polystyrene MBs (CPMs, Kisher-Biotech Inc., Steinfurt, Germany) were determined. Briefly, 100 μL IMBs was incubated with 1 mL of L. monocytogenes at different concentrations (10 4 and 10 6 CFU/mL) in a rotary shaker for 1 h at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Immunomagnetic Bead Separation Coupled with a Dithiobis-Succinimidyl Propionate (DSP)-Modified Immunosensor to DetectListeria monocytogenesin Chicken Skin

Park

2014

J. Electrochem. Soc.

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This study aimed to determine the optimal conditions for coupling immunomagnetic bead separation (IMS) with a dithiobissuccinimidyl propionate (DSP)-modified immunosensor and apply the IMS-coupled DSP-modified immunosensor to detect Listeria monocytogenes in chicken skin. Specific anti-Listeria polyclonal antibodies (pAbs) against three L. monocytogenes species were covalently immobilized on magnetic beads (MBs) to prepare immunomagnetic beads (IMBs). The optimal pAb concentration, incubation time, buffer type and pH, amount of MBs, and elution buffer for IMS were determined to be 1.0 mg/mL, 30 min, PBS buffer with a pH range from 6.5 to 7.5, 30 μL, and citric acid (pH 3.0), respectively. The number of L. monocytogenes after IMS application was 6.0 log colony-forming unit (CFU)/g during the 15-h enrichment period, as compared to 7.1 log CFU/g without IMS application. IMS coupled with a DSP-modified immunosensor decreased the incubation time to 7.5 h with a limit of detection of 10 3 CFU/25 g chicken and improved the sensitivity of the immunosensor, exhibiting a correlation coefficient (R 2 ) of 0.95. Microscopic images of the immunosensor coupled with IMS revealed less binding of food particles on MBs than binding without IMS treatment.

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“…Therefore, an assay of ATP is responsible for the concentration of bacterial cells. Firefly bioluminescence (BL) is routinely used for the detection of ATP due to the number of photons (BL intensity) is directly proportional to the concentration of ATP [5][6][7], which can be measured at femtomole levels using the luciferin-ATP reaction [8].…”

Section: Introductionmentioning

confidence: 99%

Immunomagnetic separation and rapid detection of bacteria using bioluminescence and microfluidics

Qiu

Zhang

Chen

et al. 2009

Talanta

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a b s t r a c tThis paper describes an immunomagnetic separation of target bacterial cells from others by using magnetic bead. The surface of bead was coated with antibodies which can capture specific organism. The binding efficiency of immunomagnetic bead (IMB) capturing target bacterial cells was higher than 98% when the concentrations of target and interferent bacterial cells were at the same level. The concentration of bacteria was determined indirectly by detecting adenosine 5 -triphosphate (ATP) employing bioluminescence (BL) reaction of firefly luciferin-ATP. Benzalkonium chloride (BAC) was used as an ATP extractant from living bacterial cells. We found that BAC could enhance the light emission when the concentration of BAC was less than 5.3 × 10 −2 % (w/v) and the BL intensity reached its maximum at the concentration of BAC was 2.7 × 10 −2 %, which was 10-fold stronger than that without BAC. Based on the principle of the IMB, a microfluidic chip combined with immunofluorescence assay for separating and detecting bacteria simultaneously was also developed. The IMBs were magnetically fixed in the beadbeds of chip channels with a 3-mm diameter of NdFeB permanent magnet. The target bacterial cells can be captured magnetically and observed by a fluorescent microscope.

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Reusable immunomagnetic beads in an enzyme immunoassay

Cited by 4 publications

References 12 publications

ssDNA Aptamer-Based Surface Plasmon Resonance Biosensor for the Detection of Retinol Binding Protein 4 for the Early Diagnosis of Type 2 Diabetes

ssDNA Aptamer-Based Surface Plasmon Resonance Biosensor for the Detection of Retinol Binding Protein 4 for the Early Diagnosis of Type 2 Diabetes

Immunomagnetic Bead Separation Coupled with a Dithiobis-Succinimidyl Propionate (DSP)-Modified Immunosensor to DetectListeria monocytogenesin Chicken Skin

Immunomagnetic separation and rapid detection of bacteria using bioluminescence and microfluidics

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