Surface plasmon resonance based sensor for the detection of glycopeptide antibiotics in milk using rationally designed nanoMIPs

Zeynep Altintas

doi:10.1038/s41598-018-29585-2

Abstract

Glycopeptide antibiotics are known as the last resort for the treatment of serious infections caused by Gram-positive bacteria. The use of milk products contaminated with these antibiotic residues leads to allergic reactions and sensitivity in human. Also, long-term consumption of milk products containing low levels of these antibiotics may cause the relevant bacteria to build up resistance to these last resort antibiotics. Sensitive, rapid and effective quantification and monitoring systems play a key role for their determination in milk products. Hence, molecularly imprinted nanostructures were rationally designed in this work to produce high affinity synthetic receptors to be coupled with a surface plasmon resonance sensor for the analysis of glycopeptide antibiotics in milk samples. The nanoMIP-SPR sensor enabled vancomycin quantification with the LODs of 4.1 ng mL−1 and 17.7 ng mL−1 using direct and competitive assays, respectively. The recoveries rates for two sensor methods ranged in 85–110% with RSDs below 7%. The affinity between the nanoMIP receptors and the target molecule (dissociation constant: 1.8 × 10−9 M) is mostly superior to natural receptors and other synthetic receptors. Unlike other methods commonly employed for the detection of milk contaminants this approach is extremely simple, fast and robust, and do not require pre-sample treatment.

Highlights

Glycopeptide antibiotics are known as the last resort for the treatment of life-threatening diseases caused by Gram-positive bacteria, such as Clostridium difficile, Enterococcus spp. and Staphylococcus aureus
Applying cold wash (1), high affinity nanoMIPs are collected by performing elution steps at high temperature (2), the template free receptors are obtained with this method, because nanoMIPs are removed from the template molecule rather than the template being removed from the MIP (3), the stability and size of the nanoMIPs are high owing to the selective washing and elution steps (4), a significant amount of MIPs can be obtained per synthesis that is adequate for long term experiments (5)[17,18,19,20,21]
This study has comparatively investigated the binding of vancomycin on non-imprinted polymer (NIP) and nanoMIP surfaces in the concentration range of 125–1000 ng mL−1 to further determine the specificity of the nanostructured polymeric receptors towards the target molecule

Summary

Introduction

Glycopeptide antibiotics are known as the last resort for the treatment of life-threatening diseases caused by Gram-positive bacteria, such as Clostridium difficile, Enterococcus spp. and Staphylococcus aureus. Abbreviation and charge of monomer −IA −TFMAA −MAA −UA EGMP +DEAEM HEM MBAA Acrylamide UA UAEE +VI EGDMA TFMAA applying cold wash (1), high affinity nanoMIPs are collected by performing elution steps at high temperature (2), the template free receptors are obtained with this method, because nanoMIPs are removed from the template molecule rather than the template being removed from the MIP (3), the stability and size of the nanoMIPs are high owing to the selective washing and elution steps (4), a significant amount of MIPs can be obtained per synthesis that is adequate for long term experiments (5)[17,18,19,20,21] These superior features have resulted in the successful applications of nanoMIPs in various fields such as pharmaceutical monitoring[9,13], virus quantification[18,21], endotoxin detection[22,23], development of enzyme linked immonosorbent assays (ELISA)[24,25], manufacturing of bioselective membrane filters[11], and in vivo recognition of biomarkers[26]. This work provides the most sensitive and rapid analysis using the nanoMIP receptors and it introduces two different sensor assays to effective milk sample analysis for the first time: nanomaterial-conjugated direct assay and competitive assay

Methods

Results

Conclusion