2D Photonic Crystal Protein Hydrogel Coulometer for Sensing Serum Albumin Ligand Binding

Abstract

Bovine and human serum albumin (BSA and HSA) are globular proteins that function as bloodstream carriers of hydrophobes such as fatty acids and drugs. We fabricated novel photonic crystal protein hydrogels by attaching 2D colloidal arrays onto pure BSA and HSA hydrogels. The wavelengths of the diffracted light sensitively report on the protein hydrogel surface area. The binding of charged species to the protein hydrogel gives rise to Donnan potentials that change the hydrogel volume causing shifts in the diffraction. These photonic crystal protein hydrogels act as sensitive Coulometers that monitor the hydrogel charge state. We find multiple high-affinity BSA and HSA binding sites for salicylate, ibuprofen and picosulfate by using these sensors to monitor binding of charged drugs. We demonstrate proof-of-concept for utilizing protein hydrogel sensors to monitor protein-ionic species binding.

Fabrication of 3D Photonic Crystals from Chitosan That Are Responsive to Organic Solvents

“…12,18,19 Three-dimensional photonic nanostructures were first investigated in the 1960s. 20 Nature contains various 3D structures which have developed through billions of years of evolution.…”

Photonic crystals: emerging biosensors and their promise for point-of-care applications

“…45,72,152–155 For instance, PC structures comprised of hydrogel materials can be used as biosensors for the detection of DNA, proteins, antibodies and enzymes by monitoring the changes in lattice spacing or refractive indices. 41,43,156–159 In this respect, hydrogel-based PC structures provide either quantitative spectral results or qualitative naked-eye detection of biotarget concentrations. 41 Hydrogel-based PC structures hold great promise for POC applications owing to their cost-effective fabrication and simple optical detection systems.…”

“…34–40 PC-based biosensors hold many advantages over other existing competing biosensing technologies, including cost-effective fabrication and short assay time (Table 2). PC structures have been used to detect a wide array of biotargets in biological sample matrices, such as blood, urine, sweat, and tears, 41–43 and can be fabricated using various inexpensive fabrication methods, such as colloidal self-assembly, hydrogels, and mold-based replica imprinting. 44–46 …”

Gold Nanoparticles in Photonic Crystals Applications: A Review

“…In particular, photonic band gaps in the visible range can generate the visible diffraction colors and PCs with incomplete band gaps: these materials can be used as reflective coatings for optics, waveguides for directing the propagation of light, and many other optical components. Furthermore, PCs are widely applicable in different areas such as biological and chemical sensing, tunable color displays, and many optically active components [44,45,46,47,48,49,50,51,52,53,54,55,56,57]. …”