Molecular level understanding of the interactions between nanoparticles and phospholipid membranes is imperative to predict and control the interactions between nanoparticles and living organisms in the environment. Earlier studies have focused on disruptive nanoparticle-membrane interactions. There are however weaker non-disruptive nanoparticle-membrane interactions that are yet to be explored. Our study aims to reveal and understand nanoparticle-membrane interactions that involve a significant impact on the phase of phospholipid membranes without membrane rapture. A membrane phase change is involved in many cellular processes including cellular signaling and transport. Our study makes use of fluorescence spectroscopy of the phase-sensitive membrane dye laurdan to measure the phospholipid membrane phase during and as a result of nanoparticle-membrane interactions. In laurdan fluorescence spectroscopy a value termed generalized polarization (GP) is calculated using the intensity of the two fluorescent peaks of laurdan, which correspond to the two major lipid phases. GP measurements have previously been used to measure the lipid phase of liposome model membranes when exposed to nanoparticles as a function of nanoparticle concentration. Our study focuses on obtaining the membrane GP value via deconvolution of the overlapping fluorescent peaks and elucidating the role of nanoparticle size, hydrophobicity, surface functionalization and membrane composition on the membrane GP value. Initial results suggest that nanoparticles' core material has a significant impact on the membrane GP and phase, at times even greater than the impact of nanoparticles' surface functionalization on the membrane phase.

Fluorescence spectroscopy to measure the impact of nanoparticle and membrane characteristics on membrane phase change due to nanoparticle-membrane interactions

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.