Olof Ramstrom, Ph.D.
Area 1: Antibiofilm Materials Based on Chitosan
Antimicrobial resistance is of critical concern in the healthcare sector, as the number of multidrug-resistant pathogens is increasing. Some bacterial strains can protect themselves from common antibiotics through biofilm formation. For example, Pseudomonas aeruginosa and Staphylococcus epidermidis are known to form heavy biofilms, permitting them to survive under stringent conditions and develop more resistance. To address this, we are studying drug delivery approaches that can significantly reduce or eradicate bacterial biofilms. For example, chitosan is a polycationic biocompatible polymer with intrinsic antibacterial properties that can be used as a drug delivery material. However, functionalization of the chitosan chains can potentially lead to better activity and broader applicability of these matrices. One such modification is to introduce new functionalities, such as chatechols, through the free amine groups of chitosan. Specific agents can then be used to reversibly crosslink the chitosan chains into nanoparticles or surface coatings, while concurrently encapsulating other antibiotic agents. This project involves the preparation and evaluation of these crosslinked materials for pathogen inhibition, and to study the antibiofilm activity.
Area 2: Dynamer Turn-Off/On Fluorescence
Dynamic covalent polymers (Dynamers), in which the repeating units are connected by dynamic covalent bonds, are of great importance for studying complex dynamic systems and developing novel materials. Several reversible covalent reactions are used to synthesize dynamers, among which the nitroaldol reaction is particularly important since it can produce dynamic C–C bonds. Therefore, nitroaldol reaction-based dynamers have many advantages. For example, we have found that the polymerization of certain building blocks can yield dynamers with strong, tunable fluorescence under UV light. Since the dynamer chain also contains several coordinating groups, the materials can interact with specific metal ions that can lead to intriguing property changes. Preliminary results have shown that certain metal ions can reduce or enhance the fluorescence of the dynamers, but a more thorough investigation of this phenomenon is needed. This study will, therefore, offer a better understanding of dynamer-metal ion interaction and expand the application range of this type of dynamers.