本研究首先將聚乙烯吡咯烷酮（PVP）修飾於磁性奈米粒子（MNPs）表面上，隨後將此經PVP修飾之MNPs(MNPs@PVP)和碘溶液反應，形成不溶於水且具殺菌功能之PVP-I複合物固定化MNPs。本研究使用之核心MNPs是Bayoxide E型，利用表面成長原子自由基轉移聚合法（SI-ATRP）可良好控制並有效的共價聚合PVP鏈接枝於MNPs，改變其奈米結構之化學和物理性質。經SI-ATRP修飾上PVP之MNPs以熱重分析、傅立葉轉換紅外線光譜分析、掃描式電子顯微鏡、動態光散射粒徑分析和硫代硫酸鈉滴定法確認其性質。將具殺菌功能MNPs和菌液接觸後，計算菌液中平均每毫升菌落形成單位（CFU/mL），測試其殺菌能力。MNPs表面經SI-ATRP反應2小時可修飾上0.09 g PVP/g MNPs，且可和10 mg碘形成複合物。當PVP-I修飾之MNPs其濃度為5 g/L，且革蘭氏陰性大腸桿菌和革蘭氏陽性金黃葡萄球菌之菌落數為1010 CFU/mL時可在3分鐘內達100％殺菌率，顯示其殺菌能力極佳。未再次補充碘之MNPs可重複使用至少4次且維持其100％之殺菌率。

In this study, PVP was first grafted on the surfaces of magnetic nanoparticles (MNPs), then the reaction between PVP-grafted MNPs (MNPs@PVP) and iodine was carried out to form complexation PVP-I immobilized material or water-insoluble bactericidal MNPs. MNPs that are used for the core in this work are Bayoxide E type. And the method to further develop the chemical and physical properties of nanostructures is surface-initiated atom transfer radical polymerization (SI-ATRP); by providing a method to covalently graft of polymer PVP chains in a well-controlled fashion and efficiently. PVP could be effectively grafted onto the surface of MNPs by SI-ATRP method which were confirmed by TGA, FTIR, SEM, DLS and hyposulphite titration method. The anti-bacterial of functional MNPs was tested with the mean colony forming units (CFU) counting. As the result, the as-prepared magnetic nanoparticles were demonstrated the present of PVP on the surface around 0.09 g PVP/g particles within 2 hours of reaction time and could be loaded approximately 10 mg of iodine in the complexation form. The antimicrobial activity of PVP-I functionalized magnetic nanoparticle (at concentration of 5 g/L) was found very effective as reaching 100% bactericidal rate against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus with concentration of 1010 cfu/ml within 3 min. The used obtained MNP could be reused at least 4 times without reducing its 100% antimicrobial rate by recharging iodine.

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