Adele Mastroyannis1, Colin Raston1,2, Kirsten Heimann3, Cathy Abbott4
1Chemical Sciences, Flinders University, Sturt Rd, Bedford Park SA 5042
2Institute for Nanoscale Science and Technology, Flinders University, Sturt Rd, Bedford Park SA 5042
3Marine Bioproducts Cooperative Research Centre, Tonsley SA
4Biological Sciences, Flinders University, Sturt Rd, Bedford Park SA 5042
Brown seaweed phlorotannins exhibit potent antioxidant activity, reducing UV-induced oxidative stress responsible for skin aging. Phlorotannins inhibit enzymes which break down proteins, a process responsible for wrinkle formation and dark circles. The shelf-life of phlorotannins is short, due to loss of antioxidant activity. Skin penetration of the hydrophilic phlorotannins restricts their activity to the outer skin layer (the stratum corneum). To increase efficacy of phlorotannin-based skin care products, the design of a lipophilic delivery system will allow deeper penetration into the skin. Delivery of such skin care products to the subdermal layers will ensure antioxidant activity at the site known to initiate skin aging.
Gold nanoparticles are lipophilic delivery systems that can penetrate the stratum corneum, delivering hydrophilic antioxidant molecules. Phlorotannins reduce gold chloride solutions to create gold nanoparticles, called phlorotannin-loaded gold nanoparticles. A homogenous particle size of the gold colloidal suspension is, however, not achieved, as the reaction is uncontrolled. Current protocols require long mixing time (8-48 h) but industry standard nanoparticle sizes for skin health product formulations are not achieved.
The Vortex Fluidic Device (VFD) is an advanced energy-efficient green technology that has unique and diverse applications for controlling reactions. Due to topological fluid flow-induced sheer stress, the VFD shortens reaction times required for gold nanoparticles formation. Results show that the VFD creates uniform nanoparticles at a size more suitable for sub-dermal delivery of phlorotannins. Importantly, the approach represents a green strategy for the synthesis of phlorotannin-loaded gold nanoparticles, meeting industry demand in quality and functionality.