Graduation Year
2019
Document Type
Dissertation
Degree
Ph.D.
Degree Name
Doctor of Philosophy (Ph.D.)
Degree Granting Department
Chemistry
Major Professor
Jianfeng Cai, Ph.D.
Committee Member
James Leahy, Ph.D.
Committee Member
Wayne Guida, Ph.D.
Committee Member
Feng Cheng, Ph.D.
Keywords
Antimicrobial polymers, Dendrimers, amphiphilic, γ-AApeptide, Host defense peptide
Abstract
WHO has reported that antibiotic resistance is the third major cause of human death all over the globe. Recent study, has focused on the development of new antibacterial resistance drugs. Herein, we tried to synthesis a series of polymers that can mimic the HDPs. HDPs can target the bacterial cell membrane and they have less chances to develop bacterial resistance. We synthesized the amphiphilic polycarbonates that are highly selective to Gram-positive bacteria, including multidrug resistant pathogens. The membrane disruption activity of these polymers was proved by fluorescence and TEM studies and the drug resistance study showed that the polymers don’t develop bacterial resistance. In order to further design the molecules that can target a broad spectrum of bacteria, we have designed a series of lipidated dendrimers that can target the Gram-positive and Gram-negative bacteria. These dendrimers mimic the HDPs and target the bacterial cell membrane. Dendrimers are reported to inhibit the formation of bacterial biofilm which makes them promising for their future development of antibiotic agents.
Apart from the synthesis of polymers and dendrimers as antibacterial agents, we have designed a series of small molecular antibacterial agents that are based on the acylated reduced amide scaffold and small dimeric cyclic guanidine derivatives. These molecules display good potency against a panel of multidrug-resistant Gram-positive and Gram-negative bacterial strains. Meanwhile, they also effectively inhibit the biofilm formation. Mechanistic studies suggest that these compounds kill bacteria by compromising bacterial membranes, a mechanism analogous to that of host-defense peptides (HDPs). Lastly, we also demonstrate that these molecules have excellent in vivo activity against MRSA in a rat model. This class of compounds could lead to an appealing class of antibiotic agents combating drug-resistant bacterial strains.
Scholar Commons Citation
Nimmagadda, Alekhya, "Design, Synthesis, Applications of Polymers and Dendrimers" (2017). USF Tampa Graduate Theses and Dissertations.
https://digitalcommons.usf.edu/etd/7430
