The Pennsylvania State University

The Sen Group

Nanotechnology, nanomotor, and nanopump research at Penn State

Nanomotors in Recent Literature

nanomotor citation Statistics based on ISI Web of Knowledge® (March 2018)
Citation report for "catalytic nanomotors" since their discovery at Penn State in 2004


Alicia on the microscope Alicia prepares the microscope to study collective behavior in catalytic nanomotors.

Living systems are dynamic, multifunctional, and highly responsive, and they live in changing environments. Most engineered materials, in contrast, tend to be static with a single function and are suited for more predictable environments. Access to rationally-designed dynamic materials that are capable of remodeling themselves and transforming their environment will (i) minimize waste (they will change their function and purpose rather than being single-use), (ii) improve performance (they will continuously evolve their structures to optimize performance), and (iii) accomplish tasks collectively and emergently (like a colony of ants) that a single constituent element (like a single ant) cannot perform. By making these dynamic materials to be self-powered, they will also be capable of exploring and responding to their environment (sensor applications) without being tethered to a single power source or location.

We aim to create a new paradigm for molecular-level engineering of functional materials by integrating elements of the previous approaches into a unique strategy. The work will leverage (a) the precise chemical control associated with molecular-level manipulation of materials to create functional building blocks, with (b) self-propelled mobility resulting from biomimetic catalytic energy harvesting from the local environment, with (c) the rapid and reversible assembly capabilities provided by emergent processes, with (d) the intelligence and communication capabilities that have been demonstrated in groups of interacting microorganisms, with (e) the ability to perform specific tasks in response to signals from each other and the environment. Our approach is entirely synthetic and chemical, which allows us to create dynamic, intelligent materials in a way that is not impeded by the inherent constraints of biological systems.

Research Questions

Xi, Ambika, and Kayla discussing assays Xi discusses chemotaxis assays with Ambika and Kayla.

How can we generate chemically-powered motion at the nano- and microscales?

We have shown that catalytically active nano- and microscale objects are able to convert chemical energy to mechanical work. These nanostructures can therefore move on their own, or when immobilized, act as fluid pumps. We aim to understand and manipulate the forces that cause this motion.

How can we design nanoscale machines that respond to the environment and each other?

Natural systems often exhibit collective behaviors, like migration or swarming in response to environmental stimuli. We seek to emulate these behaviors in synthetic systems. We look to control this behavior while trying to understand the mechanisms behind these interactions.

How can we leverage nano- and micromaterials for real-world applications?

These systems have potential applications in everything from sensors, transport of cargo and information processing. Our active particles do not require any external power sources, allowing them to act as sensors in remote locations. “On demand” cargo or drug delivery to specific locations can be achieved with our materials, as we have studied how to direct motion with simple analytes. Information processing is an additional avenue for our research due to the ability to couple information using chemical or light gradients and directed motion.