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본 학위 논문은 4차 암모늄 기능기를 갖는 고분자의 물리·화학적 구조 변화에 따른 항균 및 세포 독성 활성에 대한 연구이다. 항균제로 알려진 항균성 펩타이드의 한계점을 극복하고 성능을 개선하기 위해 유사 구조를 가진 4 차 암모늄 고분자를 합성하고자 원자 전이 라디칼 중합 방법으로 3차 아민 스타형과 선형 고분자를 합성하고, 3 차 아민기에 다양한 구조를 가진 알킬기를 부착하는 4 차화 반응을 통해 고분자의 형태 및 구조를 체계적으로 제어하였다. 이러한 고분자의 구조에 따라 나타나는 항균 및 세포 독성 성능 간의 연관 관계를 이해하기 위해 필요한 유체역학적 직경, 표면 전하, 분배계수를 통한 소수성 정도 등에 대한 물리화학적 특성들을 분석하였다. 집략 계수 방법을 활용하여 그람 양성균(포도상구균)과 그람 음성균(대장균)에 대한 최소 살균 농도, 시간에 따른 항균 속도 등으로 항균성을 확인하고, 용혈 활성 및 MTT 어세이를 통해 합성한 고분자가 쥐의 적혈구와 인간 폐세포에 미치는 영향을 확인했다.

Antimicrobial agents have been developed to prevent bacterial infection and address the increasing problems of antimicrobial resistance. Here, we present amphiphilic polymers for mimicking antimicrobial peptides (AMPs) to exhibit excellent antibacterial activity and low cytotoxicity by utilizing quaternary ammonium (QA)-functionalized polymer. QA-functionalized polymers with the same-centered structure were prepared by attaching different pendant groups to tertiary amine, directly, due to alleviate mammalian cell toxicity. The well-defined structure with different molecular architecture and pendant groups via atomic transfer radical polymerization (ATRP) and quaternization, respectively, enables us to compare their physico-chemical properties on antibacterial and cytotoxic activities, clearly. To characterize physico-chemical properties of polymers, hydrodynamic diameter (Dh), zeta potential, charge density and partition coefficient (log P) were analyzed. The antibacterial properties of the polymers such as kinetics and mechanism, were determined by minimum bactericidal concentration (MBC) by colony counting method against Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria due to exclude the effect of the test medium. The cytotoxicity of the polymers was investigated by hemolysis and MTT assay using mouse red blood cells (mRBCs) and human lung epithelial cells (A549), respectively and evaluated using selectivity index obtained through results of antibacterial and cytotoxic activities.

Abstracts ·································································································· i Contents·································································································· iii
Chapter 1. Introduction ·································································1
Chapter 2. Materials and Experimental Methods ·································4 
 2.1. Materials····························································································4 
 2.2. Polymer synthesis·················································································5
  2.2.1. Synthesis of star-shaped polymers (S-QAR) ·············································5
  2.2.2. Synthesis of linear polymers (L-QAR) ····················································8 
 2.3. Polymer characterization ······································································ 10
 2.4. Antibacterial performance ····································································· 11
  2.4.1. MBC in PBS ················································································ 11
  2.4.2. MIC & MBC in a LB solution ···························································· 12
  2.4.3. Time-kill kinetics assay ···································································· 13
  2.4.4. Microscopic studies········································································· 13
 2.5. Cytotoxicity of polymers······································································· 14
  2.5.1. Hemolytic activity ·········································································· 14
  2.5.2. MTT assay ··················································································· 15
Chapter 3. Results and Discussion ················································· 17
 3.1. Polymer characterization ······································································ 17
 3.2. Antibacterial activity ··········································································· 31
 3.3. Cytotoxic activity ··············································································· 39
 3.4.Bactericidalkinetics ···········································································47
 3.5. Antibacterial mechanism ······································································ 49
Chapter 4. Conclusion··············································································· 53
References ································································································· 54
국문 초록 ··················································································· 65