Förster Resonance Energy Transfer-Mediated Globular Protein Sensing Using Polyelectrolyte Complex Nanoparticles

Abstract

Polyelectrolyte complex nanoparticles (PEC NPs) are synthesized using two oppositely charged polyelectrolytes, i.e., anionic poly(sodium 4-styrene sulfonate) (PSS) and cationic poly(diallyldimethylammoniumchloride), at molar mixing ratios (n–/n+) of ≈0.4, 0.67, 0.75, and 1.5 by applying consecutive centrifugation to modify the optical property of PSS. However, for n–/n+ ≈ 0.75, PEC NPs exhibit a larger blue shift and a specific emission peak occurs at ≈278 nm for the 225 nm excitation. The mechanism of such modification of PSS emission after complex formation is proposed. This specific emission by PEC NPs nearly matches with the optical absorption wavelength of globular proteins. The emission intensity of PEC NPs is therefore quenched in the presence of globular proteins (bovine serum albumin, human serum albumin, lysozyme, and hemoglobin) through resonance energy transfer between the donor (PEC NPs) and acceptor (globular proteins). The spectral overlap integral and the variation of the separation distance from 1.8 to 2.5 nm between the donor and acceptor confirm the resonance energy transfer. Sensing of proteins by the PEC NPs is possible within the detection limit of 5 nM and therefore such PEC NPs can be used as an efficient and promising protein sensing material.

Fluorescence-Based Sensing of Pesticides Using Supramolecular Chemistry

“…Förster resonance energy transfer theory treats the energy donor and acceptor as two dipoles that interact at relatively long distances (Saini et al, 2009). A main requirement of FRET is the need for spectral overlap between the emission spectrum of the energy donor and the absorption spectrum of the acceptor, quantified as the spectral overlap integral, J (Talukdar and Kundu, 2019). While this mechanism of energy transfer has been used extensively, practical challenges in using FRET for fluorescence sensing relate to the need for spectral overlap and the fact that there is often undesired overlap between the emission spectra of the donor and the acceptor.…”

Wet‐Spinning of Biocompatible Core–Shell Polyelectrolyte Complex Fibers for Tissue Engineering

“…These properties already led to the successful application of PECs as fibrous scaffolds, hydrogels, capsules and membrane materials. [ 9,10,13–22 ] Yim [ 7 ] developed PEC scaffolds for the precise delivery and release of various biomolecules such as bovine serum albumin (BSA), vascular endothelial growth factors (VEGF) and nerve growth factors (NGF). They were able to show that PEC fibers can be easily embedded in both a hydrophilic polysaccharide as well as a hydrophobic polycaprolactone (PCL) matrix, which improved the preservation of cargo molecules while simultaneously increasing the efficiency of sustained release.…”