Sam RozansStudent: Sam Rozans

Project: Cell Responsive Biomaterials

View: Research Poster (PDF) | Presentation (YouTube)

Department: Bioengineering

Advisor: Tommy Pashuck


Cell-responsive biomaterials utilize some feature of a cell to generate a local change in the biomaterial. The Pashuck lab is interested in cell-secreted proteases as a stimulus. These enzymes cleave local peptides around only cell types which express the protease, allowing for selectivity within the hydrogel. The lab has developed a novel biomolecular switch in which proteases are able to activate nucleic acids for hybridization. These cyclic nucleic acid—peptides have potential to enable a cell-type specific response. Preliminary results indicate cyclized nucleic acid—peptides will not bind to a complimentary nucleic acid strand, while the linear version of the nucleic acid—peptide conjugates will bind to the complimentary strand. This indicates potential for a nucleic acid-peptide to mediate a state dependent on/off (linear/cyclized) response, which can be triggered through proteolytic cleavage of the peptide. Further investigation showed endogenous proteases are able to cleave the peptide, linearizing the PNA—peptide making it capable of inducing a response. This potential was further demonstrated by incubating human endothelial cells in gels which contained the cyclic nucleic acid-peptides. After 24 hours the area immediately surrounding cells, or an area where cells had been could be stained using the complimentary strand, validating that this technology can be used for targeting specific cells in a hydrogel.

About Sam Rozans

Samuel Rozans received his bachelors and masters degrees in biomedical engineering from Drexel University and is a second-year Ph.D. student studying bioengineering at Lehigh University. Under the direction of Dr. Pashuck, I research cell-responsive biomaterials. Using a multi-disciplinary approach I focuses on biomaterials that induce a cell-type specific responses. My past research in polymer synthesis and nano-to-micro scale characterization provides him with a strong foundation for success. In my free time, I enjoys hiking, climbing, and almost anything outdoors.