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Direct determination of a small-molecule drug, valproic Acid, by an electrically-detected microcantilever biosensor for personalized diagnostics.

Huang LS, Gunawan C, Yen YK, Chang KF - Biosensors (Basel) (2015)

Bottom Line: The measured surface stresses showed a profile over a concentration range of 50-500 μg·mL-1, which covered the clinically therapeutic range of 50-100 μg·mL-1.The estimated limit of detection (LOD) was calculated to be 45 μg·mL-1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL-1.Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan. lshuang@ntu.edu.tw.

ABSTRACT
Direct, small-molecule determination of the antiepileptic drug, valproic acid, was investigated by a label-free, nanomechanical biosensor. Valproic acid has long been used as an antiepileptic medication, which is administered through therapeutic drug monitoring and has a narrow therapeutic dosage range of 50-100 μg·mL-1 in blood or serum. Unlike labeled and clinically-used measurement techniques, the label-free, electrical detection microcantilever biosensor can be miniaturized and simplified for use in portable or hand-held point-of-care platforms or personal diagnostic tools. A micromachined microcantilever sensor was packaged into the micro-channel of a fluidic system. The measurement of the antiepileptic drug, valproic acid, in phosphate-buffered saline and serum used a single free-standing, piezoresistive microcantilever biosensor in a thermally-controlled system. The measured surface stresses showed a profile over a concentration range of 50-500 μg·mL-1, which covered the clinically therapeutic range of 50-100 μg·mL-1. The estimated limit of detection (LOD) was calculated to be 45 μg·mL-1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL-1. Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay.

No MeSH data available.


The similar tendency of the response signals obtained by the fluorescence polarization immunoassay (FPIA) and the present microcantilever biosensor in PBS, 50% serum and pure serum.
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biosensors-05-00037-f006: The similar tendency of the response signals obtained by the fluorescence polarization immunoassay (FPIA) and the present microcantilever biosensor in PBS, 50% serum and pure serum.

Mentions: Figure 6 compares the results of valproic acid drug detection using the proposed piezoresistive microcantilever biosensor and clinical measurements using the fluorescence polarization immunoassay (FPIA). FPIAs are homogeneous, single-step assays suited for the high-throughput screening of large numbers of samples. In clinical environments, such assays require trained staff, milliliter-scale samples and reagent volumes and a turnaround time of almost one day to complete [15]. The deflection of a cantilever biosensor was induced by drug-antibody direct interaction and binding. FPIAs are based on the competition of fluorophore-labeled valproic acid with the free (unlabeled) valproic acid drug in a sample with respect to specific capture antibodies. Both labeled and unlabeled valproic acid molecules mixed with the antibody in the same solution revealed competition in terms of molecular binding. By increasing the concentration of unlabeled valproic acid molecules in a binding competition environment, we found that the signal exhibited a low polarization reading. Meanwhile, this fluorescence polarization is quantified as milli-polarization units, or mP.


Direct determination of a small-molecule drug, valproic Acid, by an electrically-detected microcantilever biosensor for personalized diagnostics.

Huang LS, Gunawan C, Yen YK, Chang KF - Biosensors (Basel) (2015)

The similar tendency of the response signals obtained by the fluorescence polarization immunoassay (FPIA) and the present microcantilever biosensor in PBS, 50% serum and pure serum.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4384081&req=5

biosensors-05-00037-f006: The similar tendency of the response signals obtained by the fluorescence polarization immunoassay (FPIA) and the present microcantilever biosensor in PBS, 50% serum and pure serum.
Mentions: Figure 6 compares the results of valproic acid drug detection using the proposed piezoresistive microcantilever biosensor and clinical measurements using the fluorescence polarization immunoassay (FPIA). FPIAs are homogeneous, single-step assays suited for the high-throughput screening of large numbers of samples. In clinical environments, such assays require trained staff, milliliter-scale samples and reagent volumes and a turnaround time of almost one day to complete [15]. The deflection of a cantilever biosensor was induced by drug-antibody direct interaction and binding. FPIAs are based on the competition of fluorophore-labeled valproic acid with the free (unlabeled) valproic acid drug in a sample with respect to specific capture antibodies. Both labeled and unlabeled valproic acid molecules mixed with the antibody in the same solution revealed competition in terms of molecular binding. By increasing the concentration of unlabeled valproic acid molecules in a binding competition environment, we found that the signal exhibited a low polarization reading. Meanwhile, this fluorescence polarization is quantified as milli-polarization units, or mP.

Bottom Line: The measured surface stresses showed a profile over a concentration range of 50-500 μg·mL-1, which covered the clinically therapeutic range of 50-100 μg·mL-1.The estimated limit of detection (LOD) was calculated to be 45 μg·mL-1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL-1.Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan. lshuang@ntu.edu.tw.

ABSTRACT
Direct, small-molecule determination of the antiepileptic drug, valproic acid, was investigated by a label-free, nanomechanical biosensor. Valproic acid has long been used as an antiepileptic medication, which is administered through therapeutic drug monitoring and has a narrow therapeutic dosage range of 50-100 μg·mL-1 in blood or serum. Unlike labeled and clinically-used measurement techniques, the label-free, electrical detection microcantilever biosensor can be miniaturized and simplified for use in portable or hand-held point-of-care platforms or personal diagnostic tools. A micromachined microcantilever sensor was packaged into the micro-channel of a fluidic system. The measurement of the antiepileptic drug, valproic acid, in phosphate-buffered saline and serum used a single free-standing, piezoresistive microcantilever biosensor in a thermally-controlled system. The measured surface stresses showed a profile over a concentration range of 50-500 μg·mL-1, which covered the clinically therapeutic range of 50-100 μg·mL-1. The estimated limit of detection (LOD) was calculated to be 45 μg·mL-1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL-1. Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay.

No MeSH data available.