title: Multifunctional Fe₃O₄/alumina core/shell MNPs as photothermal agents for targeted hyperthermia of nosocomial and antibiotic-resistant bacteria.
abstract: OBJECTIVE
  The appearance of antibiotic-resistant bacterial strains is a serious problem in medical treatment. Thus, it is imperative to explore new therapeutic approaches and antibiotics with which to treat patients suffering from bacterial infections.
  
  
  METHODS
  In this work, we propose a targeted hyperthermia therapeutic approach using alumina-coated iron oxide magnetic nanoparticles (Fe(3)O(4)/alumina core/shell MNPs) as photothermal agents to selectively kill bacteria.
  
  
  RESULTS
  Fe(3)O(4) MNPs possess photothermal capabilities under near-infrared (NIR) light illumination. The temperature of the MNP suspension (1.33 µg/µl, 60 µl) under illumination with NIR light increased 20°C over 5 min. Functionalization of the surface of the MNPs with an alumina coating allows them to have targeting capability toward bacteria. The prepared Fe(3)O(4)/alumina core/shell MNPs possess several desirable features, including magnetic properties, absorption capability in the NIR region and the ability to target bacteria. The magnetic properties of the Fe(3)O(4)/alumina MNPs allow conjugated target species to aggregate at a specific location under a magnetic field. A NIR laser can then be used to specifically irradiate the aggregated spot to photokill target bacteria. The cell growth of nosocomial bacteria, including Gram-positive, Gram-negative and antibiotic-resistant bacterial strains, can be effectively inhibited by over 95% within 10 min of light irradiation when targeted by Fe(3)O(4)/alumina MNPs.
  
  
  CONCLUSIONS
  This approach provides a potential therapeutic approach for treating patients suffering from nosocomial and antibiotic-resistant bacterial infections.
authors.affiliation: Department of Applied Chemistry, National Chiao Tung University, Hsinchu 300, Taiwan.
authors.forename: Tsai-Jung
authors.initials: TJ
authors.lastname: Yu
authors.forename: Po-Han
authors.initials: PH
authors.lastname: Li
authors.forename: Te-Wei
authors.initials: TW
authors.lastname: Tseng
authors.forename: Yu-Chie
authors.initials: YC
authors.lastname: Chen
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D001419:Bacteria / Q000528:radiation effects*; D001424:Bacterial Infections / Q000628:therapy; D002460:Cell Line; D003428:Cross Infection / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005290:Ferric Compounds / Q000737:chemistry*; D006090:Gram-Negative Bacteria / Q000528:radiation effects; D006094:Gram-Positive Bacteria / Q000528:radiation effects; D006801:Humans; D006979:Hyperthermia, Induced / Q000379:methods*; D058185:Magnetite Nanoparticles / Q000009:adverse effects / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D010789:Phototherapy / Q000379:methods*
chemical_list: D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C000499:ferric oxide; D000537:Aluminum Oxide