Janus Liposomes in Motion

With the support of the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Wei Zhan and his research group at Auburn University will develop a new type of biocompatible, micromotor based on Janus liposomes. Janus liposomes are small spherical particles of lipid bilayer formed by self-assembly in water. Janus liposomes are comprised of two halves with different structures – hence their name after, Janus, the two-faced Roman god of change and duality.

If successful, this research will yield small-sized objects that can perform directional motion in response to low electric fields, light, or biological agents such as cholesterol and enzymes. These stimulus-responsive moving particles potentially will be useful in several areas, for example, as biosensors or for targeted cargo delivery. Results of this research will be broadly disseminated in the literature, but also through internet-based educational platforms that reach the general public.

In addition, the Zhan group plans to conduct outreach activities such as providing for hands-on science-related experiences for elementary school students and their parents.

The Zhan group at Auburn University has pioneered the development of asymmetric Janus liposomes as a new class of lipid-based assembled nanostructure. In this ongoing research, Janus liposomes will be designed to contain reactive building blocks that would allow for directional movement against Brownian motion and viscous drag in water, taking advantage of their broken surface symmetry and chemical heterogeneity.

Three fundamental driving forces or gateways will be employed to propel these self-assembled particles: (i) electric fields,(ii) light and (iii) enzymatic reactions (lowers activation barrier). Together, these efforts will substantially advance understanding on the mechanisms, capabilities and applications of active/directional motion of Janus liposomes – an underexplored class of materials in an otherwise rapidly growing field.

Such a systematic approach will also likely yield insight into building multi-responsive, function-programmable micromotors. This research is targeting a lipid architecture that has long served as a prototype of biological cells and has the potential to shed new light on the function and collective behavior of natural motors.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.