Development of a water-in-oil-in-water multiple emulsion system integrating biomimetic aqueous-core lipid nanodroplets for protein entity stabilization. Part II: process and product characterization

Abstract

The aqueous-core enclosed in lipid nanoballoons integrating multiple emulsions of the type water-in-oil-in-water mimic, at least in theory, the environment within viable cells, thus being suitable for housing hydrophilic protein entities such as bioactive proteins, peptides and bacteriophage particles. This study reports a complete physicochemical characterization of optimized biomimetic aqueous-core lipid nanoballoons housing hydrophilic (BSA) protein entities, evolved from a statistical 2³×3¹ factorial design study (three variables at two levels and one variable at three levels) that was the subject of the first paper of a series of three, aiming at complete stabilization of the three-dimensional structure of protein entities attempted via housing the said molecular entities within biomimetic aqueous-core lipid nanoballoons integrating a multiple (W/O/W) emulsion. The statistical factorial design followed led to the production of an optimum W/O/W multiple emulsion possessing quite homogeneous particles with an average hydrodynamic size of (186.2 ± 2.6) nm and average Zeta potential of (−36.5 ± 0.9) mV, and exhibiting a polydispersity index of 0.206 ± 0.014. Additionally, the results obtained for the diffusion coefficient of the lipid nanoballoons integrating the optimized W/O/W multiple emulsion were comparable and of the same order of magnitude (10⁻¹² m² s⁻¹) as those published by other authors since, typically, diffusion coefficients for molecules range from 10⁻¹⁰ to 10⁻⁷ m² s⁻¹, but diffusion coefficients for nanoparticles are typically of the order of magnitude of 10⁻¹² m² s⁻¹.

Keywords:

• Aqueous-core lipid nanoballoons
• diffusion coefficient
• infrared spectrophotometry with Fourier transform
• protein entities
• Stokes–Einstein equation
• structural and functional stabilization
• water-in-oil-in-water multiple emulsions
• X-ray diffraction analysis

Acknowledgements

Project funding by Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP, São Paulo, Brazil) (FAPESP Ref. No. 2013/03181–6, Project PneumoPhageKill), is hereby gratefully acknowledged.

Disclosure statement

The authors have no conflicts of interest whatsoever to declare, and report no declarations of interest.

Funding information

This work also received support from CNPq, National Council for Scientific and Technological Development – Brazil, in the form of Research Productivity (PQ) fellowships granted to Victor M. Balcão (Ref. No. 306113/2014–7) and Marco V. Chaud (Ref. No. 309598/2014–1).