“We often look to mother nature for interesting things. When scientists take a look at these things, it often involves the nanoworld,” said Kevin Walsh, associate dean of research and facilities, professor of electrical engineering at UofL’s and founding director of UofL’s Micro/Nano Technology Center (MNTC).

Cicada wings’ antibacterial properties in particular interested University of Louisville engineers. Along with UofL biologists, the team analyzed the nanostructure of the insects’ wings and developed a nanofabrication technique to replicate it for potential use in spaces where bacteria are undesirable, such as food service, health care facilities and medical devices.

The team, led by Chuang Qu, Walsh and Mark Running, has developed a process to synthesize a surface material that mimics the wings’ structure and has the same antibacterial and water repellant properties as the wings that inspired it. The development and testing of the innovative manufacturing process was made possible through the use of , which include a scanning electron microscope (SEM) and nanomaterial production capabilities.

With the help of an SEM, scientists can see that cicada wings’ surface consists of tiny, bowling-pin-shaped structures with a diameter of around 100 nanometers – about one-thousandth of the diameter of a human hair. The wings owe their antibacterial properties to the spike-shaped tops which act like daggers, piercing the cellular membranes of bacteria that have the misfortune of landing on them, ultimately killing the bacteria.

To replicate the cicada wings’ nanopillar cone structure, Qu, a senior research engineer at Speed School specializing in advanced nanofabrication, developed a two-step process of self-assembly and glancing-angle deposition (GLAD).

“All the structures we discovered under the microscope are challenging to recreate because they are so small and three-dimensional,” Qu said. “Using a two-step self-assembly plus glancing angle deposition, we were able to recreate the structure and confirm that, like their cicada wing template, they have these antimicrobial properties.”

The manufacturing method consists of two processes. First, bases of the nanopillars are created using self-assembly, in which the material spontaneously falls into place. To create the tips of the bowling pin shapes, the researchers used GLAD, a technique in which physical vapor is deposited onto the base structure at an oblique angle. This procedure reduces the number of steps required to manufacture complex nanostructure materials that is cheaper and more scalable than other methods.

To verify the antibacterial effect of the nanostructure they had developed, the team tested it using E. Coli, common bacteria that have a fairly tough cell wall. Examining the effects of the manufactured surface on bacteria using the SEM at MNTC, the researchers found that the new material functioned in the same way as the cicada wings – destroying the bacteria with its dagger-like spikes.

Since the cicada wings and the replica material rely on physical nanostructures to kill the bacteria and can be made of virtually any material, the surfaces avoid possible negative effects of chemical antimicrobials in biomedical applications.

“We didn’t know it was going to be physical and that we would be able to detect it, so I was really happy that we were able to determine that,” said Mark Running, a UofL biology professor and coauthor of the .

While further work is needed to fully adapt the material to commercial use, it has potential for applications such as on doorknobs or other surfaces that need to be kept clean and germ free, food preparation surfaces and implantable medical devices that are prone to bacterial infection. The team has filed a provisional patent on a process called “inverted GLAD” to create materials such as the cicada wing replication and is seeking to hire students to assist with additional research.

“The challenges are how to scale the production up to larger areas and how to apply them to curved surfaces,” Walsh said. “Right now, we can just use it on flat surfaces.”

UofL’s MNTC facilities are available for use by researchers within and outside of UofL, as well as businesses conducting product research and development. It is one of 16 facilities at universities nationwide funded by the National Science Foundation to support research and industry. MNTC is one of eight advanced manufacturing facilities in the , a consortium of resources at UofL and the University of Kentucky.

The , held this year from July 31 through August 1 at the UofL Swain Student Activities Center, will showcase the latest research and advances from in and around Kentucky, including work in 3-D printing and manufacturing at the micro/nano-scale.

“Kentucky has always been a manufacturing state, but we need to innovate and continue to advance,” said Dr. Kevin Walsh, associate dean of research and facilities at the UofL J.B. Speed School of Engineering, who’s leading the event. “This forum provides a way for us to annually get together, discuss new findings, share results, showcase capabilities, generate ideas, debate the future and network with one another.”

The conference also includes hands-on workshops on additive manufacturing, roll-to-roll printing and micro-fluidics. The symposium will feature nationally-known keynote speakers, poster presentations, facility tours, networking, a cocktail reception and an investor forum backed by the .��

The event’s keynote speakers are: Harold Sears, a Ford Motor Company rapid manufacturing technical leader often called a “3-D printing futurist;” Dr. Edward Kinzel, an aerospace and mechanical engineering professor at the University of Notre Dame; Dr. Philip Rack, a professor of materials science at The University of Tennessee, and Dr. Placid Ferreira, an endowed professor of material science and engineering from the University of Illinois.��

The annual conference is a��partnership between UofL and the University of Kentucky. Together, they offer a collection of advanced manufacturing core facilities open to industry and academia, called the Kentucky Multi-Scale Network.��

Attendees can tour UofL’s multi-scale facilities, including the Micro-Nanotechnology Center (MNTC) cleanroom, the Rapid Prototyping Center (RPC) and the Conn Center for Renewable Energy Research. Those facilities work with industry on a variety of projects, from to��saving energy when manufacturing cement.

Kentucky Multi-Scale is part of the , which consists of 16 academic sites across the U.S. with similar advanced core facilities. Some of its other members include Harvard, Stanford and Cornell universities.

You can register to attend the 2019 Nano+AM Symposium ��

The group was a part of the Innovative Partnership Program (IPP) created through XPRIZE and��Singularity University in alliance with Deloitte. According to IPP program director Sean Watson, the goal of the two-day tour is��to help senior business executives from leading companies explore the future of manufacturing and product development, as well as discover new ecosystems and partnerships that they can tap into to thrive in the emerging agile manufacturing paradigm.��

“As we looked at the lay of the land in manufacturing, we saw that Louisville was doing some really special things and a lot of it centered around the capabilities of the university,” Watson said. “We wanted to expose these companies to an industrial ecosystem outside Silicon Valley – the places you typically think of as centers of innovation in the world – and to introduce them to places doing dynamic things and are emerging as new centers and new ‘brain belts’.”

While the tour was created for informational and educational purposes, UofL Senior Director of Research Support & Development William A. Metcalf says he is hoping that the exposure will lead to additional public-private partnerships.

“Hopefully, they see some of the exciting things happening here and want to get involved, whether that’s research or to co-locate here and hire our students,” Metcalf said. “We’re not selling anything today, per se, but we’re talking about what we do. Hopefully, they find that interesting and want to be a part of it.”

More photos from the tour are .��