Antibody mimetics for the detection of small organic compounds using a quartz crystal microbalance

TY - JOUR

T1 - Antibody mimetics for the detection of small organic compounds using a quartz crystal microbalance

AU - Koutsoumpeli, Eleni

AU - Tiede, Christian

AU - Murray, James

AU - Tang, Anna

AU - Bon, Robin

AU - Tomlinson, Darren

AU - Johnson, Steven David

N1 - © 2017, American Chemical Society. This is an author-produced version of the published paper. Uploaded in accordance with the publisher’s self-archiving policy. Further copying may not be permitted; contact the publisher for details.

PY - 2017/3/7

Y1 - 2017/3/7

N2 - Conventional immunoassays rely on antibodies that provide high affinity, specificity and selectivity against a target analyte. However, the use of antibodies for the detection of small-sized, non-immunogenic targets, such as pharmaceuticals and environmental contaminants presents a number of challenges. Recent advances in protein engineering have led to the emergence of antibody mimetics that offer the high affinity and specificity associated with antibodies but with reduced batch-to- batch variability, high stability and in vitro selection to ensure rapid discovery of binders against a wide range of targets. In this work we explore the potential of Affimers, a recent example of antibody mimetics, as suitable bio-receptors for the detection of small organic target compounds, here methylene blue. Target immobilisation for Affimer characterisation was achieved using long-chained alkanethiol linkers coupled with oligoethyleneglycol (LCAT-OEG). Using quartz crystal microbalance with dissipation monitoring (QCM-D), we determine the affinity constant, KD , of the methylene blue Affimer to be comparable to that of antibodies. Further, we demonstrate the high selectivity of Affimers for its target in complex matrices, here a limnetic sample. Finally, we demonstrate an Affimer-based competition assay, illustrating the potential of Affimers as bioreceptors in immunoassays for the detection of small-sized, non-immunogenic compounds.

AB - Conventional immunoassays rely on antibodies that provide high affinity, specificity and selectivity against a target analyte. However, the use of antibodies for the detection of small-sized, non-immunogenic targets, such as pharmaceuticals and environmental contaminants presents a number of challenges. Recent advances in protein engineering have led to the emergence of antibody mimetics that offer the high affinity and specificity associated with antibodies but with reduced batch-to- batch variability, high stability and in vitro selection to ensure rapid discovery of binders against a wide range of targets. In this work we explore the potential of Affimers, a recent example of antibody mimetics, as suitable bio-receptors for the detection of small organic target compounds, here methylene blue. Target immobilisation for Affimer characterisation was achieved using long-chained alkanethiol linkers coupled with oligoethyleneglycol (LCAT-OEG). Using quartz crystal microbalance with dissipation monitoring (QCM-D), we determine the affinity constant, KD , of the methylene blue Affimer to be comparable to that of antibodies. Further, we demonstrate the high selectivity of Affimers for its target in complex matrices, here a limnetic sample. Finally, we demonstrate an Affimer-based competition assay, illustrating the potential of Affimers as bioreceptors in immunoassays for the detection of small-sized, non-immunogenic compounds.

UR - http://www.scopus.com/inward/record.url?scp=85020088577&partnerID=8YFLogxK

U2 - 10.1021/acs.analchem.6b04790

DO - 10.1021/acs.analchem.6b04790

M3 - Article

SN - 0003-2700

VL - 89

SP - 3051

EP - 3058

JO - Analytical Chemistry

JF - Analytical Chemistry

IS - 5

ER -