Self-assembly of the polymer brush-grafted silica colloidal array for recognition of proteins

Abstract

Three-dimensional photonic crystal sensors are attractive platforms for autonomous chemical sensing and colorimetric bioassays. At present, the photonic crystal sensors with inverse opal structure were extensively studied, which swells or shrinks in response to the analytes. However, the fabrication of inverse opal sensors still remains a major challenge. Herein, we propose a simple and versatile approach to fabricate 3D opal photonic sensors. This photonic crystal is fabricated via assembly of monodispersed silica particles grafted with linear polymeric ligands (SiO@LPs). Acrylic acid (negatively charged monomer) and N-tert-butylacrylamide (hydrophobic monomer) were incorporated with N-isopropylacrylamide to achieve strong affinity between the designed polymer ligands and proteins. The proposed photonic crystal displays a maximum redshift of 23 nm in response to 2 mg/mL lysozyme, accompanied by the structure color change from blue to green. Compared to the cross-linked polymers, the linear polymer with flexible structure allows the colloidal array to recognize lysozyme with higher sensitivity (as low as 5 μg/mL) and broader linearity (from 5 to 2000 μg/mL in aqueous media). In the future, this photonic crystal sensor can be used as universal tools for the detection of a broad range of analytes. Graphical abstract Colloidal array self-assembled by polymer brush-grafted silica for proteins detection.

Fundamentals and Applications of Polymer Brushes in Air

“…Finally, some sensor designs for liquid environments may also work under gases. For instance, in one study, opal-like arrays of silicon nanoparticles coated with brushes containing hydrophobic and negatively charged blocks were shown to change in color in the presence of lysozyme proteins, due to the change in Bragg reflection wavelength as the brush swelling alters the periodicity of the structure . While this was demonstrated in a liquid environment, a solvent vapor in air is from a thermodynamic perspective comparable to a minority component with strong polymer affinity in a poor background solvent, suggesting that concepts like this may extend to the gas phase as well.…”

Multi-Factors Cooperatively Actuated Photonic Hydrogel Aptasensors for Facile, Label-Free and Colorimetric Detection of Lysozyme

“…The conformational change induced by the specific binding between the aptamer and lysozyme enables an increase in the cross-linking density of the hydrogel, resulting in its shrinkage. Furthermore, the adjacent carboxyl groups and the hydrophobic N-tert-butyl groups simultaneously interact with lysozyme molecules, which also is helpful to the shrinkage of the hydrogel [ 52 , 53 , 54 ]. Herein, in PBS solution of pH 7.40, the carboxyl groups are negatively charged, and lysozyme is positively charged because its isoelectric point is ~10.8.…”

Synthetic strategies to enhance the long-term stability of polymer brush coatings

“…[6][7][8] Moreover, this strong brush swelling can be employed in the design of anti-fouling surfaces as well. [9][10][11][12][13] Other biomimetic materials, where polymer brushes have been incorporated, have been designed to display environmentally responsive [14][15][16] and structural [17][18][19] colours, as found in e.g. chameleons.…”