Design and simulation of a caprylic acid enzymatically modified phosphatidylcholine micelle using a coarse-grained molecular dynamics simulations approach

Abstract

Computationally simulated micelle models provide useful structural information on the molecular and biological sciences. One strategy to study the self-aggregation process of surfactant molecules that make up a micelle is through molecular dynamics (MD) simulations. In this study, a theoretical approach with a coarse-grained MD simulation (CG-MD) was employed to evaluate the critical micellar concentration (CMC), the micellization process, building a tridimensional (3D) model system of a micelle using data from the experimentally enzymatically modified phospholipids (PL) by phospholipase A1 (PA1). This required enzymatic interesterification of soybean phosphatidylcholine (PC) with caprylic acid, along with purification and characterization by chromatographic techniques to measure the esterified fatty acids and the corresponding PL composition. The number of molecules used in the CG-MD simulation system was determined from the experimental CMC data which was 0.025%. The molecular composition of the system is: 1 C 18:2, 2 C 8:0/8:0, 3 C 8:0/18:3n-9, 4 C 8:0/18:0, 5 C8:0/18:2n-6, 6 C8:0/18:1n-9, and 7 C 8:0/16:0. According to our theoretical results, the micelle model is structurally stable with an average Rg of 3.64 ± 0.10 Å, and might have an elliptical form with a radius of 24.6 Å. Regarding CMC value there was a relationship between the experimental data of the modified PLs and the theoretical analysis by GC-MD, which suggest that the enzymatic modification of PLs does not affect their self-aggregation properties. Finally, the micellar system obtained in the current research can be used as a simple and useful model to design optimal biocompatible nanoemulsions as possible vehicles for bioactive small molecules.

Communicated by Ramaswamy H. Sarma

Keywords:

• Phospholipid
• amphiphilic
• interesterification
• self-assembly
• coarse grain

Acknowledgment

Y.S.L. thanks to SECTEI (Secretaria de Educación, Ciencia, Tecnología e Innovación de la Ciudad de México) for a Postdoctoral Fellowship.

Disclosure statement

The authors have no relevant financial or non-financial interests to disclose.

Author’s contribution

D.S.L. and Y. S. L., wrote the manuscript, made the figures, and analyzed theoretical results; D.S.L. D. B. A., and C. C. S. performed experimental assays; D.S.L., Y. S. L., H. S. G., and J. C. B. designed the project and wrote the manuscript. All authors read and approved the final manuscript.

Additional information

Funding

This work was supported by 250784 and CB-254600 granted by The National Council for Science and Technology of Mexico (CONACyT). The authors gratefully acknowledge the scholarship from CONACyT for graduate studies of authors Santos-Luna D., and Bravo-Alfaro D.A.