UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS

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2025-07-06 15:07
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Conference: Bucharest University Faculty of Physics 2025 Meeting


Section: Biophysics; Medical Physics


Title:
Impact of Gramicidin A-loaded nanoparticles (NPs-GA) on membrane fluidity


Authors:
Diana-Lavinia STAN (1,2), Mihaela BACALUM (2)


Affiliation:
1) University of Bucharest, Faculty of Physics, 405 Atomistilor Street, P.O. Box MG-11, 077125 Magurele, Romania



2) “Horia Hulubei” National Institute for Physics and Nuclear Engineering, Măgurele, Romania



E-mail
diana.stan@nipne.ro; bmihaela@nipne.ro


Keywords:
Gramicidin A, Laurdan, membrane fluidity


Abstract:
Aiming to develop more effective anticancer therapies, this study investigated if the effects induced by Gramicidin A (GA) are improved following its incorporation into nanoparticles (NPs-GA). GA is a peptide known for its ability to form selective ion channels in cell membranes and induce cancer cell death (1). The impact of NPs-GA on membrane fluidity was assessed using Laurdan, a polarity-sensitive fluorescent probe (2), in model membranes composed of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) and cell membranes. Initial experiments focused on model membranes composed of POPC, analyzing the effects of temperature variation (10 ℃ to 60 ℃, in 10 ℃ steps) at fixed concentrations of GA and NPs-GA (1 µM and 25 µM), as well as concentration-dependent effects (1 µM to 25 µM) at two constant temperatures (20 ℃ and 37 ℃). The impact of GA and NPs-GA was further evaluated on two distinct colorectal cancer cell lines, HCT 116 and HT-29, under the same experimental conditions to assess cell-specific membrane responses. Finally, cell viability post-treatment confirmed peptide insertion and GA-loaded nanoparticles into cell membranes, as indicated by generalized polarization (GP) measurements, demonstrating the successful integration of both free GA and NPs-GA into the membrane.


References:

(1) Kelkar D. A., Chattopadhyay A., The gramicidin ion channel: a model membrane protein, Biochimica et Biophysica Acta (BBA)-Biomembranes 1768, 9, 2011-2025, 2007

(2) Parasassi T., Gratton E., Membrane lipid domains and dynamics as detected by Laurdan fluorescence, Journal of fluorescence 5, 59-69, 1995