Abstract
AbstractVolume amplitude gratings made of mesoporous hydrogels are beneficial for sensing, but are difficult to fabricate because they involve creating high aspect ratio features in soft materials. A novel photofunctionalizable hydrogel is reported and its suitability for fabricating grating sensors is demonstrated comprising of features with an aspect ratio of ≈3.2. To make a photofunctionalizable hydrogel with high optical quality that can be patterned using widely available light sources, a water‐soluble photoactive monomer and sensitizer are synthesized. A transmission amplitude grating is subsequently fabricated in a ≈100 µm thick photofunctionalizable hydrogel film by reaction of the free amines generated in the photoexposed regions with pH‐responsive fluorescein isothiocyanate. The volume hydrogel grating described herein is shown to be suitable for real‐time sensing of pH as an exemplar analyte. This work will have a significant impact on the fabrication of diffractive optical structures in thick films of hydrogels that are highly promising for biomolecular sensing in disease diagnosis and healthcare monitoring.
Highlights
Volume amplitude gratings made of mesoporous hydrogels are beneficial transmitted in a specified direction as for sensing, but are difficult to fabricate because they involve creating high aspect ratio features in soft materials
A transmission amplitude grating is subsequently fabricated in a ≈100 μm thick photofunctionalizable hydrogel film by reaction of the free amines generated in the photoexposed regions with pH-responsive fluorescein isothiocyanate
A novel photofunctionalizable hydrogel has been developed for selective immobilization of pH-sensitive dye in ≈100 μm thick films to fabricate a transmission amplitude grating
Summary
We used a well-studied photolabile group, NVOC, for synthesizing our photofunctionalizable hydrogels. ThX is a widely reported triplet sensitizer that provides an efficient means to populate the photoreactive state of NVOC derivatives using light of long wavelength (≈405 nm vs 350 nm) and has been used in this work. We initially synthesized NVOC-allylamine monomer, but it was only sparingly soluble in water. We achieved water-soluble photoactive hydrogel monomer and sensitizer by incorporating quaternary ammonium and PEG groups with an average Mn of 900 g mol−1 into NVOC and ThX, respectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
