Nov 2, 2021
Amir Nasajpour
Led by PhD student Amir Nasajpour in Professor Paul Weiss’s lab, the research engineered spiky rose thorn-like nanomaterial that establishes great antibacterial activity to slow herpes simplex virus 1 and 2 (HSV). 
The viral infection causes blisters that break and leave sores around the affected areas including mouth (HSV-1) and genital (HSV-2). An estimate of more than 3.7 billion people under age 50 have HSV-1 around the globe, while more than one out of every six people aged between 14 to 49 suffers from HSV-2 nationwide. Current treatment can only relieve the symptoms before a cure is developed. 
The research is built on the group’s previous work to engineer branched zinc oxide (ZnO) nanoparticles into biocompatible polycaprolactone (PCL) polymer scaffold via electrospinning. The resulting branched particles protruded from the fibers’ surfaces, giving a structure similar to rose spike in nature. The current work tested the effect of zinc oxide tetrapod nanoparticles (ZOTeN) against HSV.
Finding shows the unique geometry demonstrated better antiviral activities compared to standard commercial zinc oxide nanoparticles. 
“Zinc oxide is commonly used in sunscreens to reflect/scatter the sun’s rays, but here we re-engineered it into the fabric (PCL) because it’s also a non-toxic, green oxidant.” Nasajpour said, “By generating rose-like morphology, we are able to generate higher activity using the least amount of zinc oxide nanomaterials in the composite, reducing associated cost.”  
They found the photocatalyst ZOTeN is activated in the presence of blue light, which helps accelerate the reaction of molecular hydrogen (H2) and water (H2O) in PCL to produce hydrogen peroxide (H2O2)---a natural oxidant released by certain immune cells under bacterial infection.
ZOTeN has a stronger binding affinity to HSV-1 receptors than HSV targeted human cells human corneal epithelial cell lines (HCE). The nanomaterial immobilizes the viral particle upon interaction and sterilizes the virus through the photochemical reaction. 
A plaque assay shows a ZOTeN concentration-dependent effect on plaque formation. High concentration of ZOTeN significantly reduces the formation of HSV due to a higher number of ZOTeN sites available to attach virus. 
“This is the first generation of ZOTeN used to test against HSV.” Nasajpour said, “Our goal is to commercialize it. We have some industry companies interested in different applications of ZoTeN...Ultimately, we hope our research can mitigate the spread  of HSV.” 
The future work is to perform in vivo experiments including animal trials and consider applying the nanomaterial to antiviral garments and face coverings.  
“This work is really just the start of using these materials...Those applications are guiding our next steps in research.” Weiss said, “Amir is a terrific and creative scientist. He is so full of ideas that we have to pick and choose which to explore and then which to bring to fruition.”
Professor Paul Weiss holds a UC Presidential Chair and is a distinguished professor of chemistry & biochemistry, bioengineering, and materials science & engineering. He leads an interdisciplinary research group focused on understanding and controlling chemistry, physics, biology, and materials at the smallest scales. He is the founding, and current, Editor-in-Chief of ACS Nano, one of the top scientific journals in nanoscience and nanotechnology. From 2009–2014 Weiss held the Fred Kavli Chair in NanoSystems Sciences and was the director of the UCLA California NanoSystems Institute, of which he is a member.
Amir Nasajpour (pictured at top) is a fourth-year materials track graduate student in the department. He is interested in using bio-inspired engineering to address materials for industry as well as biomedical challengings. He earned his BS in molecular biology at the University of Florida. Nasajpour was recently accepted to the Cellular Agriculture Fellowship (CAS) as a technical advisor.
By Zhuoying Lin, UCLA Department of Chemistry & Biochemistry, Lin is a first year chemistry graduate student and science writer.