Surface functionalization allowing repetitive use of optical sensors for real‐time detection of antibody‐bacteria interaction

Abstract

In this study, sensor surface functionalization allowing the repetitive use of a sensing device was evaluated for antibody-based detection of living bacteria using an optical planar Bragg grating sensor. To achieve regenerable immobilization of bacteria specific antibodies, the heterobifunctional cross-linker N-succinimidyl 3-(2-pyridyldithio) propionate (SPDP) was linked to an aminosilanized sensor surface and subsequently reduced to expose sulfhydryl groups enabling the covalent conjugation of SPDP-activated antibodies via disulfide bonds. The immobilization of a capture antibody specific for Staphylococcus aureus on the sensor surface as well as specific binding of S. aureus could be monitored, highlighting the applicability of optical sensors for the specific detection of large biological structures. Reusability of bacteria saturated sensors was successfully demonstrated by cleaving the antibody along with bound bacteria through reduction of disulfide bonds and subsequent re-functionalization with activated antibody, resulting in comparable sensitivity towards S. aureus.

Waveguide Enhanced Raman Spectroscopy for Biosensing: A Review

“…Amino-terminated surfaces also permit the attachment of thiol-terminated biomolecules using the heterobifunctional cross-linker N -succinimidyl 3-maleimidopropionate (SMP) (Scheme ii). The use of disulfide bonds, such as N -succinimidyl 3-(2-pyridyldithio)­propionate (SPDP), offers the advantage of surface regeneration for repeated biosensing measurements . Epoxy chemistry is an alternative coupling approach for biomolecule immobilization given its stability under aqueous conditions and its reactivity to several nucleophiles; it can be used to conjugate thiol-, amine-, or hydroxyl-terminated biomolecules. , However, the reaction of amines with epoxides requires the reaction medium to be at high ionic strength, which can cause denaturation of proteins …”

TiO2 surface functionalization of COC based planar waveguide Bragg gratings for refractive index sensing

“…Primarily, Bragg grating sensors are applied for measuring temperature or strain [2,3]. However, since a change of the effective refractive index leads to a shift of the Bragg wavelength, these structures can also be used for refractive index sensing, which allows for an application of the sensor devices in liquid and gaseous analytics, chemical sensing and bio sensing [4][5][6][7]. Following this, these devices can find various fields of application, reaching from industrial process monitoring to medical diagnostics.…”

Tracking a photo-switchable surface-localised supramolecular interaction via refractive index

“…An alternative parameter to interrogate is the refractive index of an optical mode adjacent to the surface; surface-localised refractive index measurement (typically via surface plasmon resonance, but also interferometry, ring resonators or gratings) has the benefit of being label-free and has been successfully applied to biological and to a lesser extent, chemical sensing. [22][23][24][25][26] However, it remains highly challenging to separate a subtle change in surface-localised refractive index induced by a supramolecular interaction from fluctuations in refractive index originating from environmental phenomena (principally temperature or concentration).…”