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Synthesis of CMRD-Super Paramagnetic Iron Oxide Particles

Reagents:

  • Ferric Chloride Hexahydrate
  • Ferrous Chloride Tetrahydrate
  • Milli-Q water molecular grade water
  • Carboxymethyl Reduced Dextran (CMRD) (approx. 20% solution)
  • Inert gas (nitrogen or argon)
  • 28% Ammonium Hydroxide

Materials/Equipment:

  • Balance
  • Weigh boats
  • 500 ml auto-cleavable screw top bottle and magnetic stir bar
  • Water bath or Ice (depending on desired production temp)
  • Hot plate with stirring
  • 50 ml graduated cylinder
  • 10 ml pipettes
  • 1000 ul pipette
  • 50 ml centrifuge tubes for reagent aliquots and storage
  • 100 ml beaker
  • Thin plastic bucket used for temperature bath
  • Thermometer

Procedure:

  1. Add 14 ml of CMRD and 56 ml of Milli-Q water to a 500 ml screw top bottle with stir bar and begin stirring
  2. Weigh 2 g of Ferric Chloride Hexahydrate and add to 27 ml of Milli-Q water in a 100 ml beaker.
  3. Weigh 1 g of Ferrous Chloride Tetrahydrate and add to beaker from step 2 solution in 100 ml beaker until completely dissolved.
  4. Add iron solution from step 4 into the 500 ml container container CMRD from step 1
  5. Briefly mix solution and purge ambient air with inert gas for 2 minutes (cap immediately)
  6. Prepare water bath for reaction temperature of choice (ice, room temp, etc)
  7. Let 500 ml container sit with cap on for 10 minutes to equilibrate at the desired temp.
  8. Set up apparatus for temp sink during particle creation as follows:
    1. Place large bucket on hot plate (ensure bucket is thin enough for stir bar to work).
    2. Attach thermometer to edge for temperature monitoring
    3. Add correct temperature water to bucket (either from water bath or use ice water).
    4. Place 500 ml container in bucket.
  9. Make sure temperature is correct and add 8.5 g of Ammonium hydroxide over two minutes (make sure cap is always partially covering top of container).
  10. After the addition of Ammonium hydroxed let stir for 5 min covered.
  11. Heat for 2 hr at 70°C.
  12. Store particles at 4°C.