Development of liposomal immunosensor for the measurement of insulin with femtomole detection [An article from: Analytica Chimica Acta]

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2006. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The monitoring of insulin is of great relevance for the management of diabetes, the detection of pancreatic islet-cell malfunction, the definition of hypoglycemia, and the diagnosis of insulinoma. A liposomal immunosensing system for the determination of insulin was developed in this study. The insulin sensor was constructed by the immobilization of anti-insulin antibodies on the inner wall of the microcapillary immunoseparator. Liposomes tagged with anti-insulin and encapsulating a fluorescent dye were used as the detectable label. In the presence of insulin, sandwich immunocomplexes were formed between the immobilized antibodies in the column, the sample of insulin, and the antibody-tagged sulforhodamine B-dye-loaded liposomes. Signals generated by lysing the bound liposomes with 30mM n-octyl-@b-d-glucopyranoside were measured by a fluorescence detector. The detected signal was directly proportional to the amount of insulin in the test sample. The liposomal immunosensing system successfully detected as low as 136attomole. MeOH (30%) was used for the regeneration of antibody-binding sites in the microcapillary after each measurement, which allowed the immunoseparator to be used for at least 70 repeated assays. The antibody activity in this proposed microcapillary immunoseparator could be well maintained for at least 1 week. The calibration curve for insulin in Tris-buffered saline had a linear dynamic range of 10pM-10nM, and the total assay time was less than 30min. The coefficient of variation for triplicate measurements was