Abraham Joy is an Assistant Professor in the Department of Polymer Science at the University of Akron, USA. Recently we had the opportunity to interview him about his research within biomaterials- and biomedical applications.
Professor Joy has a Ph.D. in Organic Chemistry from Tulane University. He carried out postdoctoral work in the area of bioorganic chemistry at Georgia Tech. Subsequently he did a second postdoc at the New Jersey Center of Biomaterials, and that’s where he started working with polymers and specifically within biomaterials applications which lead him to his position at Akron. Now let’s get to the interview:
– Tell us a little bit about your research
“My group works on developing materials for biomedical applications and we utilize skills of organic chemistry and polymer chemistry to address some emerging needs within biomedical applications. A current focus area in the lab is in designing densely functionalized materials. If you think about natural polymers such as proteins, they have a variety of functional groups. As a consequence of their functional groups and their 3D arrangement they have a wide variety of properties and functions. Synthetic materials such as PLGA or PCL are used for their mechanical or physical properties but they don’t have any functionality designed into them.
So we are trying to demonstrate the idea of developing synthetic materials wherein they have the traditional advantages of reproducibility and scale-up, but also the type of functionality seen in peptides. At the end of the day we have materials, or a biomaterial platform, that has all the functional groups that look as if they were peptides but the backbones are either polyesters or polyurethanes. Such densely functionalized polyesters and polyurethanes can potentially be used for several biomedical applications wherein a degradable or a non-degradable platform would be required.”
– What biological functions are you driving towards or hoping to achieve with the peptide-like polyesters. Is it signaling into the cell or other kinds of functions?
“So what we hypothesize is that because these peptide-like polyesters have so many types of functionalities we could access several different areas. But as a matter of what we first started with and due to the expertise of our collaborators, we are now working on the following areas: one area is where we are trying to use the functionalities of these polymers to direct stem cell differentiation. […] Another area that we are engaged in is to design functionalized polyesters that mimic bio-glue or bio-adhesives such as those secreted by mussels.
Another application that we are currently exploring is to design synthetic mimics of antimicrobial peptides. These peptides have a large number of cationic residues and a large number of hydrophobic residues. Incorporating cationic lysine or arginine mimics and hydrophobic valine or phenylalanine mimics is something that we can easily engineer into the design of our polyesters or polyurethanes. So we make polymers with varying compositions of a lysine mimic and a valine mimic and examine antimicrobial activity against strains like E-coli or Staphylococcus Aureus and we are seeing promising data to indicate that they do have antimicrobial activity.
The advantage here is that because it is a modular platform, we can make materials water soluble, or hydrophobic; we can make them high molecular weight or low molecular weight. So the design feature allows you to access very different properties. We could make them water soluble where they would function as an injectable therapeutic or as a high molecular weight polymer where you coat it onto an implant to make the implant antimicrobial.”
– It is really interesting with the idea with the flexible scaffold that depending on the length of the polymer and the peptides that you use, you get so many possible applications out of it, like stem cell differentiation or antimicrobials. So one follow-up – the antimicrobial coatings, is that to prevent biofilm formation on devices or is that the kind of longer term idea?
“Yes it is exactly for those kinds of applications. Now if you talk to medical device companies, they would like to have, let’s say a polyurethane coating that presents some form of antimicrobial activity. And the most common way is to incorporate silver ions into the polymer, but we are trying to make the material itself present antimicrobial properties without having to leach out other agents that are added in there so that we can prevent biofilm formation.