Soft glass multi-channel capillaries as a platform for bioimprinting

Abstract

Multi-channel capillaries (MC) formed from thousands individual microcapillaries with diameters ranging 10–100 μm are of a great interest for their use as platforms for molecular imprinting due to their relatively large surface area, high mechanical stability and possibility of facile integration in sensor systems. The manuscript proposes a new format of immunoassay based on imprinted protein immobilized on a MC inner surface modified with poly-l-lysine. The combination of the environmentally friendly, easy-to-produce and cheap recognition element with the carrier allowing to increase the assay sensitivity makes the described technique a perspective alternative for the existing screening tests. Two bioimprinting approaches were described. The imprinted protein (ovalbumin, OVA) primarily prepared separately and later immobilized on a MC structure was compared to the imprinted OVA directly prepared on the MC surface. Detection of a food contaminant zearalenone was chosen as a proof-of-concept. In a case of the immobilization of the primarily prepared imprinted OVA the reached limit of detection (LOD) was 0.8 ng/mL, and for the in-situ imprinted OVA the LOD was 0.12 ng/mL. The sensitivity of the developed bioimprinted assay was comparable to the commercially available ELISA kits for ZEN detection.The OVA in-situ imprinted on the MC surface was tested for the detection of ZEN in artificially spiked wheat samples. The high recovery values (88–112%) and good repeatability (RSD of 8.5–9.6%) were demonstrated allowing to conclude that the IPs-based MC-ELISA is a promising tool for analysis of the mycotoxin in complex matrices.