Label-free immunosensing by long period fiber gratings at the lowest order cladding mode and near turn around point. (October 2021)

• Record Type: Journal Article
• Authors: Dey, Tanoy Kumar; Tombelli, Sara; Biswas, Palas; Giannetti, Ambra; Basumallick, Nandini; Baldini, Francesco; Bandyopadhyay, Somnath; Trono, Cosimo
• Is Part Of: Optics & laser technology. Volume 142(2021)
• Publication Date: 2021-10
• Subjects: Long period fiber grating -- Turn around point -- Lowest order cladding mode -- Label free immunoassay -- Human serum -- Limit of detection (LOD); Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2021.107194
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Fabrication of long period fiber gratings with lowest order cladding mode near turn around point. Maximum enhancement of the evanescent field of the sensor. Microfluidic thermostated flow-cell. Label free IgG/anti-IgG immunoassay performed in human serum. Limit of detection 0.16 ng/ml (1.06 pM). Information on the binding kinetics. Abstract: A long period fiber grating has been fabricated by combining two sensitivity enhancement techniques, the turn around point (TAP) and the maximum enhancement of the evanescent field by obtaining the lowest order cladding mode (LP0, 2 cladding mode). A label-free immunoglobulin G/anti immunoglobulin G (IgG/anti-IgG) immunoassay in serum has been performed with the sensor inside a thermostated closed flow cell. Real time kinetics of the IgG and anti-IgG binding has been monitored and evaluated. By measuring the dual peak resonance of the LP0, 2 cladding mode, a limit of detection of 0.16 ng/ml (1.06 pM) for anti-IgG has been achieved.