Biophysical Characterization of lipid diacetylene mixtures during UV exposure

CANDIDO SL; ACHILLI E; CALIENNI MN; ALVIRA F; ALONSO SDV

Congreso; XLIX Reunión Anual SAB 2021; 2021

Sociedad Argentina de Biofísica

Interest in polymer lipids arose as an option to combine both liposomes and polymer characteristics in one system, extensively showing its biocompatibility. The design of nano-photopolymerizable liposomes relies on two advantages: lipid self-assembly properties and photoactivable bonds in diacetylene lipids moiety along their acyl chain. Closely packed and adequately ordered, diacetylene lipids undergo polymerization when they are irradiated with UV photons. Under these illuminationconditions, liposomes show 1,4-addition to form alternating ene-iyne polymer chains. Thus, this study aimed to evaluate the potential use of the binary and ternary mixtures of polymerizable diacetylene lipid 1,2-bis (10,12-tricosadiynoyl) -sn-glycero-3-phosphocholine (DC8,9PC) with DMPC, DOTAP, DSPE PEG 2000, and DSPE PEG 2000 amine,which will be used in the design of a photosensitive nanocarrier for drug delivery. UV-Vis, FTIR spectroscopy, Bright Field microscopy, DLS, Z potential, and rheology were studied in the liposomes. An overview of UV diacetylene nano-size, its structural and functional characterization is provided. The degree of polymerization and polymer length was estimated between 5-11 monomers units. We performed a deconvolution analysis of ATR-FTIR. The deconvolution revealed at least three prominent peaks in the monomer state and broad background peaks that appear upon UV exposure. Peaks of the DC8,9PC over the range 2300-1900 cm-1 show an expected significant change: reducing the triple carbon bond to double carbon-carbon bond (C = C). Region 1750-1650 cm-1 shows the vibrational modes of hydrogen bonding of the headgroup. The region 1500-1450 cm-1 corresponds to CH2 inplane bending and CH2 symmetric stretching, hence packing alkyl chains. The formulations developed show good stability (high z potential), small size enough (15 nm average, measured by DLS), and good cellular uptake and biocompatibility probability. Acknowledgments: Authors wish to thank to Mg. L. Martinez for his help with rheology experiments.