Internal Structure of Nanometer-Sized Droplets Prepared by Antisolvent Precipitation.
Isabel Schuldes1, Dennis M Noll1, Torben Schindler1
1Institute for Crystallography and Structural Physics , Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Staudtstr. 3 , 91058 Erlangen , Germany.
Langmuir : the ACS Journal of Surfaces and Colloids
|September 25, 2019
Summary
Antisolvent precipitation successfully created exceptionally small organic nanoparticles (NPs) of coenzyme Q10. These NPs exhibit a unique core-shell structure, demonstrating molecular ordering at their interface, even without stabilizers.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Antisolvent precipitation (AP) offers a cost-effective and less invasive method for organic nanoparticle (NP) preparation compared to top-down techniques.
- Previous studies indicate molecular ordering at the interface of liquid NPs for various materials, independent of stabilizers.
- Coenzyme Q10 (Q10) is a ubiquinone with potential applications in nanotechnology.
Purpose of the Study:
- To present a detailed structural characterization of very small liquid coenzyme Q10 (Q10) nanoparticles prepared by antisolvent precipitation.
- To investigate the influence of different stabilizers (sodium dodecyl sulfate and pentaethylene glycol monododecyl ether) and the absence of stabilizers on Q10 NP formation and structure.
- To determine the minimum size and stability of Q10 NPs prepared via AP.
Main Methods:
- Nanoparticle preparation using antisolvent precipitation (AP).
- Size analysis via photon correlation spectroscopy (PCS).
- Structural characterization using differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), contrast variation small-angle neutron scattering (SANS), wide-angle X-ray scattering (WAXS), and cryogenic transmission electron microscopy (CryoTEM).
Main Results:
- Successfully prepared stable Q10 nanoparticles down to 19.9 nm in size, with stability lasting over 16 months, even without stabilizers.
- The smallest organic nanoparticles prepared by AP to date were achieved using SDS-stabilized Q10.
- A core-shell structure was identified, comprising an amorphous Q10 core and a shell of oriented Q10 and SDS molecules, indicating amphiphilic behavior and a stabilizing role for Q10.
Conclusions:
- Antisolvent precipitation is a viable method for producing exceptionally small and stable organic nanoparticles, exemplified by coenzyme Q10.
- The observed core-shell structure and interfacial molecular ordering highlight the inherent amphiphilic properties of Q10 and suggest its self-stabilizing capability.
- These findings advance the understanding of organic NP formation and interfacial phenomena, with implications for drug delivery and materials science.
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