By Kwok Fan Chow
The Kennedy College of Science, Department of Chemistry, invites you to attend a dissertation defense by Ruogu Tang entitled “Novel Antimicrobial and Antifouling Polymeric Materials.” The defense will be held in Olney 518 (North Campus) on Friday, March 24 at noon.
Committee Chair: Prof. Yuyu Sun, Department of Chemistry, University of Massachusetts Lowell
- Prof. James Reuther, Department of Chemistry, University of Massachusetts Lowell
- Prof. James Whitten, Department of Chemistry, University of Massachusetts Lowell
- Prof. Kwok-Fan Chow, Department of Chemistry, University of Massachusetts Lowell
Biofouling caused by microbial contamination and biofilm formation has caused serious problem in environmental, industrial and medical fields, and its has become a global threat. In this dissertation, three different polymeric materials and related systems were developed to achieve antimicrobial and antifouling functions.
In the first part, N-halamines, a family of compounds containing oxidative halogens attached to nitrogens, were used as antifouling additives for aquatic paints. Three types of chlorine-based polymeric N-halamines, amine-based N-halamines, amide-based N-halamines, and copolymers containing both amine and amide N-halamines were synthesized. The polymeric N-halamines were added into commercial vessel paints as additives, and the modified paints were coated on vessel-used substrates that are commonly used in marine vessels. A long-term chlorine stability study showed that the N-halamine-containing paints slowly and continuously released a small amount of free chlorine in both seawater and freshwater for more than 60 days. The N-halamine-containing paints demonstrate the antifouling effects against bacteria, fungi and algae.
The second part focused on development of a cyanuric chloride-based reactive dyeing treatment technology, to introduce the antimicrobial and biofilm-controlling functions into hydroxyl- or amino-containing polymers. The sodium 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate, which was a colorless dichloro-s-triazine (DCT) reactive “dye”, was synthesized. With cellulose as example, the synthesized colorless reactive dye and the reactive blue 4 (a commercial DCT reactive dye) were covalently bound to cellulose (reactive dyeing), followed by hydrolysis to transform the remaining chloride into hydroxyl groups. The reactive dyed cellulose presented potent antimicrobial functions against S. epidermidis, E. coli and C. albicans, and effectively prevented the formation of bacterial or fungal biofilms. Model compound study suggested that the antimicrobial activities of reactive dyes were associated with the phenol-like hydroxyl groups on the triazine rings that could cause microbial lysis and leakage of intracellular components.
In the third part, the cellulose based polymeric aldehyde was achieved as a new class of antimicrobial compound. The cellulosic polymeric aldehyde was synthesized via the oxidation of cellulose that transform the hydroxyl groups into aldehyde groups. The aldehyde functional groups could be adjusted by changing the experiment conditions to provide different levels of antimicrobial functions. On the contrary to most aldehyde compounds, which is toxic for direct human contact, the cellulosic polymeric aldehyde was biocompatible with mammalian cells. In the in the cell-bacteria co-culture system, the cellulosic polymeric aldehyde prevented the bacteria adhesion and maintained the viability of mammalian cells.
All interested students and faculty members are invited to attend.