Evaluation of the Physico-Chemical Properties of Liposomes Assembled from Bioconjugates of Anisic Acid with Phosphatidylcholine

Abstract

The aim of this work was the evaluation of the physico-chemical properties of a new type of liposomes that are composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine. In particular, the impact of modified anisic acid phospholipids on the thermotropic parameters of liposomes was determined, which is crucial for using them as potential carriers of active substances in cancer therapies. Their properties were determined using three biophysical methods, namely differential scanning calorimetry (DSC), steady-state fluorimetry and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). Moreover, temperature studies of liposomes composed of DPPC and bioconjugates of anisic acid with phosphatidylcholine provided information about the phase transition, fluidity regarding chain order, hydration and dynamics. The DSC results show that the main phase transition peak for conjugates of anisic acid with phosphatidylcholine molecules was broadened and shifted to a lower temperature in a concentration- and structure-dependent manner. The ATR-FTIR results and the results of measurements conducted using fluorescent probes located at different regions in the lipid bilayer are in line with DSC. The results show that the new bioconjugates with phosphatidylcholine have a significant impact on the physico-chemical properties of a membrane and cause a decrease in the temperature of the main phase transition. The consequence of this is greater fluidity of the lipid bilayer.

Acylglycerols of Myristic Acid as New Candidates for Effective Stigmasterol Delivery—Design, Synthesis, and the Influence on Physicochemical Properties of Liposomes

“…Liposomes were prepared using mixture of newly synthesized acylglycerols ( 4,5 ) and dipalmitoylphosphatidylcholine (DPPC). The procedure was based on the hydration of a dry film and was described in previous papers [ 50 ]. Liposomes were formed using different molar ratios of the acylglycerol to DPPC (n acylglycerol /n DPPC ): 0.01, 0.02, 0.05, 0.1, and 0.2.…”

“…The final concentration of the lipid in the sample was 25 mg/mL. The method was described precisely in our previous papers [ 50 , 51 ]. Prepared liposomes were incubated for 48 h at 4 °C and measured using Mettler Toledo Thermal Analysis System D.S.C.…”

“…The excitation and emission wavelengths were as follows: for DPH, λ exc = 360 nm and λ em = 425 nm; for Laurdan, λ exc = 360 nm and the emission wavelengths were λ em = 440 nm and λ em = 490 nm. The details of this procedure was described in our previous papers [ 50 , 51 ].…”

Understanding the Transepithelial Transport and Transbilayer Diffusion of the Antihypertensive Peptide Asn-Cys-Trp: Insights from Caco-2 Cell Monolayers and the DPPC Model Membrane

“…Figure a shows the pretransition of pure DPPC lipid bilayers from the gel phase to the ripple phase transition, which occurs at 33.3 °C due to the rearrangement of lipid head groups . Upon the addition of NCW, the pretransition disappeared suggesting an interaction between NCW and polar head groups of the lipid bilayers. , The presence of NCW in DPPC liposomes caused a disordering effect on the surface of DPPC liposomes, leading to an increase in lipid bilayer fluidity . The main transition (Tm) from an ordered ripple phase to a disordered liquid crystalline phase of pure DPPC, caused by alkyl chains, was observed at 40.97 °C, which was in accordance with a previous study .…”

Conjugates of 1,3‐ and 1,2‐Acylglycerols with Stigmasterol: Synthesis, NMR Characterization, and Impact on Lipid Bilayers

“…The measurements were made at three selected temperatures: 25, 37 and 45 °C (below and above the main phase transition of DPPC) at the ratio of DPPC to the acylglycerol of 5 : 1. A detailed description of the method was reported in our previous papers [35,68] …”