title: Nanoparticles as smart treatment-delivery systems in plants: assessment of different techniques of microscopy for their visualization in plant tissues.
abstract: OBJECTIVE
  The great potential of using nanodevices as delivery systems to specific targets in living organisms was first explored for medical uses. In plants, the same principles can be applied for a broad range of uses, in particular to tackle infections. Nanoparticles tagged to agrochemicals or other substances could reduce the damage to other plant tissues and the amount of chemicals released into the environment. To explore the benefits of applying nanotechnology to agriculture, the first stage is to work out the correct penetration and transport of the nanoparticles into plants. This research is aimed (a) to put forward a number of tools for the detection and analysis of core-shell magnetic nanoparticles introduced into plants and (b) to assess the use of such magnetic nanoparticles for their concentration in selected plant tissues by magnetic field gradients.
  
  
  METHODS
  Cucurbita pepo plants were cultivated in vitro and treated with carbon-coated Fe nanoparticles. Different microscopy techniques were used for the detection and analysis of these magnetic nanoparticles, ranging from conventional light microscopy to confocal and electron microscopy.
  
  
  RESULTS
  Penetration and translocation of magnetic nanoparticles in whole living plants and into plant cells were determined. The magnetic character allowed nanoparticles to be positioned in the desired plant tissue by applying a magnetic field gradient there; also the graphitic shell made good visualization possible using different microscopy techniques.
  
  
  CONCLUSIONS
  The results open a wide range of possibilities for using magnetic nanoparticles in general plant research and agronomy. The nanoparticles can be charged with different substances, introduced within the plants and, if necessary, concentrated into localized areas by using magnets. Also simple or more complex microscopical techniques can be used in localization studies.
authors.affiliation: Centro de Investigaciones Biológicas, CSIC, Ramiro de Maeztu 9, E-28040 Madrid, Spain.
authors.forename: P
authors.initials: P
authors.lastname: González-Melendi
authors.forename: R
authors.initials: R
authors.lastname: Fernández-Pacheco
authors.forename: M J
authors.initials: MJ
authors.lastname: Coronado
authors.forename: E
authors.initials: E
authors.lastname: Corredor
authors.forename: P S
authors.initials: PS
authors.lastname: Testillano
authors.forename: M C
authors.initials: MC
authors.lastname: Risueño
authors.forename: C
authors.initials: C
authors.lastname: Marquina
authors.forename: M R
authors.initials: MR
authors.lastname: Ibarra
authors.forename: D
authors.initials: D
authors.lastname: Rubiales
authors.forename: A
authors.initials: A
authors.lastname: Pérez-de-Luque
mesh_terms: D001692:Biological Transport; D028464:Cucurbita / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D007501:Iron / Q000737:chemistry; D008280:Magnetics; D053768:Metal Nanoparticles / Q000032:analysis*; D018613:Microscopy, Confocal / Q000379:methods*; D046529:Microscopy, Electron, Transmission / Q000379:methods*; D008856:Microscopy, Fluorescence / Q000379:methods*
chemical_list: D007501:Iron