Laser Precision

doctor Guisbiers with laser

Dr. Guisbiers’ laser setup for creating nanoparticles

Dr. Gusibiers and his Students combat antibiotic immunity with lasers

The growing resistance to antibiotics and other forms of infection treatment is becoming a growing threat around the world today. Many infections that at one time were treated with antibiotics are now becoming immune to this form of treatment. According to the Center for Disease Control, at least 2.8 million people are diagnosed with antibiotic-resistant infections every year from which 35,000 die. Additionally, a number of cancer cells are becoming resistant to chemotherapy. 

According to the World Health Organization, “antimicrobial resistance threatens the very core of modern medicine and the sustainability of an effective, global public health response to the enduring threat from infectious diseases.” 

This growing trend is encouraging doctors and scientists to formulate new ways to combat these diseases. Dr. Grégory Guisbiers from the Department of Physics and Astronomy at UA Little Rock and his students are hard at work to find a solution using nanomedicine, the practice of using nanomaterials in medicine. Along with Dr. Thomas J. Webster from Northeastern University, Guisbiers is experimenting with a new method to create pure naked nanoparticles. The nanoparticles are considered “naked” when they do not have any other substances surrounding them. 

“The surface of the particle is totally naked, so it can interact very efficiently with the bacteria itself” Guisbiers said. 

These tiny “naked” nano-drugs are made of selenium, an essential mineral that shows promising benefits in cancer, cardiovascular, thyroid, and disease research. Selenium is a rare mineral found in the Earth’s core that has been classified as a critical resource by the American Physical Society and Materials Research Society. The project’s research team  is making the most of this chemical element by using lasers to create a unique selenium nano-drug. This eco-friendly method can create nanoparticles sized between a few to several hundred nanometers having various morphologies from spheres to rods or wires. The size and shape of the nanoparticles are controlled by the laser’s parameters such as power, fluence, repetition rate, and wavelength.

To set up this process, the target made of selenium pellets is placed in a chemistry flask and covered with a solvent. The laser, placed on the opposite side of the flask, shoots to a mirror. The mirror directs the laser down to a lens and onto the selenium pellets. The laser exposes the pellets to radiation, which changes the color of the liquid and produces the nanoparticles. Once synthesis is complete, Guisbiers and his students send the samples to Northeastern University in Boston to test their anti-bacterial and anti-cancer properties. Before shipment, the particle mixture solution’s concentration is determined by Atomic Emission Spectroscopy, a chemical analysis method that determines the amount of particles in the solution. The size distribution is determined by Dynamic Light Scattering, a technique that measures the size of nanoparticles. More advanced characterization is also performed by using the electron microscopes available on campus throughout the Nano-center. 

Currently, the research team has tested the nano-drug on four different strains of bacteria at different concentrations: MRSA, E. coli, S. epidermidis, and P. aeruginosa. As the nanoparticles’ concentration increases, the rate of bacterial survival rapidly diminishes. Since the nanoparticles are “naked,” they can directly interact with the bacteria very efficiently at a lower concentration than if they were chemically synthesized.

Graphic detailing synthesis protocol called Pulsed Laser Ablation in Liquids (PLAL)

Graphic detailing synthesis protocol called Pulsed Laser Ablation in Liquids (PLAL)


Preparing Students for the Future

UA Little Rock student Tina Hesabizadeh holding copper selenide nanoparticles after laser treatment

UA Little Rock student Tina Hesabizadeh holding copper selenide nanoparticles after laser treatment

Three graduate and six undergraduate UA Little Rock students are involved in Guisbiers’ lab group. They get first-hand research experience by synthesizing the nanoparticles themselves.  Not only do they run experiments in the lab and learn how to characterize their own samples, but they also have the chance to collaborate on writing research papers. Dr. Guisbiers keeps pushing his students to publish. 

“Whatever your result is, it has to be reported, Guisbiers said. “If it is not reported, your result simply does not exist because it did not reach the community.” 

Students working with the selenium nanoparticles were credited in the article, “Naked Selenium Nanoparticles for Antibacterial and Anticancer Treatments” published in ACS Omega, an international peer-reviewed journal edited by the American Chemical Society. 

Several students working with Guisbiers are recipients of the UA Little Rock Signature Research Experience grants. This unique program is designed to inspire undergraduate students to pursue research and creative projects to enhance their learning experience on campus. Each recipient receives $1,000 to undergo a research project, creative activity, or community service project. Four students have received this funding to work with Guisbiers on this project. According to Guisbiers, this project is very enticing to students who want to enter medical school after they graduate from UA Little Rock. 

“When I ask the students what they want to do, I try to find a project that matches their interest with my interest, so there is a compromise,” Guisbiers said. “And they always tell me they want to go to med school or work with nanoparticles that have fancy properties like antibacterial or anti-cancer properties.” 

The Power of Nanotechnology

Guisbiers and his students also apply this laser technology to other applications besides nanomedicine. They also create quantum dots, tiny crystals that transport electrons, with this technology. Nanotechnology, he explains, can open the door to new discoveries in materials science due to its ability to modify the main characteristics of materials. 

“The main idea of nanotechnology is that when you shrink the size of your material, you’re modifying the physical and chemical properties of the material,” Guisbiers said. “And we try to bet on that to get new and exotic properties that we cannot get with bulk material, even if it’s the same compound…the main idea is to control the size, shape, and composition, so we can tune their properties.” 

One example he gives is the color change in gold. Once gold has shrunken to a smaller size, the colloidal solution of gold nanoparticles becomes purple. This physical modification fundamentally changed the optical properties of gold. 

“When students see that with their own eyes, they get on board immediately,” Guisbiers said. As everybody knows “seeing is believing.”

As he moves forward with his research, he will continue mentoring students and introducing them to new experiments and ideas for using nanotechnology to enhance society, cure diseases, and discover new ways to implement nanomaterials in our daily life. By training a group of future scientists and medical doctors, UA Little Rock students will be equipped with the knowledge they need to move forward with new advances in nanomedicine and other forms of nanotechnology, especially at a time when it is needed more than ever. 

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