Micro-bead injection spectroscopy for label-free automated determination of immunoglobulin G in human serum

• Type: Article in International Scientific Journal
• Date: 2018

Authors

Ramos, II (Author) Other; Magalhaes, LM (Author) Other; Barreiros, L (Author) Other; Salette Reis (Author) FFUP; Lima, JLFC (Author) FFUP; Marcela A Segundo (Author) FFUP

Journal

Title: Analytical and Bioanalytical Chemistry

Vol. 410

Pages: 981-988

ISSN: 1618-2642

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 4 Citations

Scopus - 6 Citations

Other information

Authenticus ID: P-00N-0SG

DOI: 10.1007/s00216-017-0601-6

Abstract (EN): Immunoglobulin G (IgG) represents the major fraction of antibodies in healthy adult human serum, and deviations from physiological levels are a generic marker of disease corresponding to different pathologies. Therefore, screening methods for IgG evaluation are a valuable aid to diagnostics. The present work proposes a rapid, automatic, and miniaturized method based on UV-vis micro-bead injection spectroscopy (mu-BIS) for the real-time determination of human serum IgG with label-free detection. Relying on attachment of IgG in rec-protein G immobilized in Sepharose 4B, a bioaffinity column is automatically assembled, where IgG is selectively retained and determined by on-column optical density measurement. A "dilution-and-shoot" approach (50 to 200 times) was implemented without further sample treatment because interferences were flushed out of the column upon sample loading, with minimization of carryover and cross-contamination by automatically discarding the sorbent (0.2 mg) after each determination. No interference from human serum albumin at 60 mg mL(-1) in undiluted sample was found. The method allowed IgG determination in the range 100-300 mu g mL(-1) (corresponding to 5.0-60 mg mL(-1) in undiluted samples), with a detection limit of 33 mu g mL(-1) (1.7 mg mL(-1) for samples, dilution factor of 50). RSD values were < 9.4 and < 11.7%, for intra and inter-assay precision, respectively, while recovery values for human serum spiked with IgG at high pathological levels were 97.8-101.4%. Comparison to commercial ELISA kit showed no significant difference for tested samples (n = 8). Moreover, time-to-result decreased from several hours to < 5 min and analysis cost decreased 10 times, showing the potential of the proposed approach as a point-of-care method.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8