Issue 17, 2017

Charged poly(N-isopropylacrylamide) nanogels for use as differential protein receptors in a turbidimetric sensor array

Abstract

Due to the high cost and environmental instability of antibodies, there is precedent for developing synthetic molecular recognition agents for use in diagnostic sensors. While these materials typically have lower specificity than antibodies, their cross-reactivity makes them excellent candidates for use in differential sensing routines. In the current work, we design a set of charge-containing poly(N-isopropylacrylamide) (PNIPAM) nanogels for use as differential protein receptors in a turbidimetric sensor array. Specifically, NIPAM was copolymerized with methacrylic acid and modified via carbodiimide coupling to introduce sulfate, guanidinium, secondary amine, or primary amine groups. Modification of the ionizable groups in the network changed the physicochemical and protein binding properties of the nanogels. For high affinity protein–polymer interactions, turbidity of the nanogel solution increased, while for low affinity interactions minimal change in turbidity was observed. Thus, relative turbidity was used as input for multivariate analysis. Turbidimetric assays were performed in two buffers of different pH (i.e., 7.4 and 5.5), but comparable ionic strength, in order to improve differentiation. Using both buffers, it was possible to achieve 100% classification accuracy of eleven model protein biomarkers with as few as two of the nanogel receptors. Additionally, it was possible to detect changes in lysozyme concentration in a simulated tear fluid using the turbidimetric sensor array.

Graphical abstract: Charged poly(N-isopropylacrylamide) nanogels for use as differential protein receptors in a turbidimetric sensor array

Supplementary files

Article information

Article type
Paper
Submitted
11 mai 2017
Accepted
17 jul 2017
First published
19 jul 2017

Analyst, 2017,142, 3183-3193

Charged poly(N-isopropylacrylamide) nanogels for use as differential protein receptors in a turbidimetric sensor array

H. R. Culver, I. Sharma, M. E. Wechsler, E. V. Anslyn and N. A. Peppas, Analyst, 2017, 142, 3183 DOI: 10.1039/C7AN00787F

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements