Natural and Synthetic Glycosylated Materials for Biomedical Applications

Date/Time
Date(s) - 09/28/2020
3:00 pm - 4:00 pm

Location
Virtual via Zoom

Renjie Liu, Ph.D., Postdoctoral Researcher, Department of Biomedical Engineering, University of Florida

Zoom Link

Renjie Li, Ph.D.

Highly abundant in nature, carbohydrates not only provide an energy source for cell metabolism, but they also specifically interact with a broad range of biomolecules, including lectins, growth factors, and other carbohydrates. Binding events involving carbohydrates are often weak, with dissociation constants in the milli- to micromolar range; however, carbohydrate-ligand interactions can be significantly enhanced by multivalency, often referred to as the “glycocluster effect”. Inspired by these observations, natural and synthetic materials that mimic the glycocluster effect are receiving increasing interest in medicine and biotechnology.

In this seminar, I’ll present our work in collaboration with the Resende Lab on a sweet corn-derived dendritic polysaccharide, phytoglycogen, in terms of its physical, biological, and biomedical properties. We investigated the influence of sweet corn lines, mutation, extraction methods, and harvesting time on the toxicity of phytoglycogen extracts toward cells. The results show that the toxicity profile varies with phytoglycogen types. In particular, while phytoglycogen extracted from one sweet corn line induces dose-dependent cell death, another phytoglycogen type shows no toxicity at all tested concentrations. We further selected some of the non-toxic variants for protein stabilization against freeze-thaw cycles. Results show that many of the non-toxic phytoglycogen extracts can stabilize proteins, demonstrating their potential for use in biotechnology applications.

I’ll also discuss our work using co-assembling peptides to create glycosylated nanoparticles for targeted enzyme delivery. Proteins modified with one co-assembling peptide are efficiently incorporated into nanoparticles using simple fabrication strategies. The fabrication protocols can be adapted to incorporate various enzymes without loss of activity. Attaching a carbohydrate onto the other co-assembling peptide provides glycosylated protein nanoparticles. The amount of carbohydrate governs the extent of accumulation of nanoparticles within cells, highlighting the potential of this approach for therapeutic enzyme delivery.

Bio

Dr. Renjie Liu is currently a postdoctoral associate in the J. Crayton Pruitt Family Department of Biomedical Engineering at the University of Florida. He earned his BS degree at the Department of Materials Science and Engineering from Donghua University in 2014 and obtained his PhD at the Department of Materials Science and Engineering from Queen Mary, University of London in 2018. During his PhD study, he actively mentored undergraduate students and also serving as a teaching assistant for several undergraduate classes. As a postdoctoral researcher, Dr. Liu now works on the fabrication of co-assembly peptide-based nanomaterials for targeted enzyme delivery and investigate the biomedical performance of a sweet corn-derived dendritic polysaccharide. Additionally, he also involves extensively in multiple collaboration projects both internally and with external universities. His research interests include the development of biomaterials for tissue engineering and cargo delivery.