User:Karlena L. Brown/Notebook/PVOH Research/2013/02/20

OBJECTIVES

• Prepare more microspheres samples expanding upon new previous method developed
• Begin fluorescence detection through pressure testing analysis of hydrogel samples

Expanded Method of PVOH Clay Microsphere Preparation

1. In 50mL beaker, dissolve ~ 1.0g total of PVOH 146K or PVOH 130K along with clay additive selected in 25mL hot deionized H₂O
2. Place a stir bar in the 50mL beaker and then heat solution at 100°C for ~ 12-15 minutes until complete dissolution of PVOH / clay sample
3. Cool solution for ~ 5 minutes, then remove the stir bar, and add PVOH clay sample to a blender.
4. Afterwards, then add 35mL rather than 25mL of mineral oil to the sample in the blender.
5. Blend sample solution prepared in blender for ~ 7 minutes on high to form a more homogeneous mixture / emulsion (creating a suspension of microspheres)
6. After 7 minutes, quickly pour solution into several mini 10mL vials and then add some Rhodamine 6G dye to the solution based upon the ratio selection (90:10 vs. 50:50)
7. Next, quickly freeze the PVOH clay sample immersed in safflower oil in liquid nitrogen for ~ 5 min. The vial should be held in the liquid nitrogen until the sample is completely frozen throughout.
8. After the addition of the dye and liquid nitrogen freezing, allow the solution to go through freeze / thaw crosslinking process for ~ 2-3 days
9. Place microsphere solution in a freezer at -20°C for 24 hours and then remove and allow to solution to thaw for 24 hours

PVOH 146K Prepared Samples & Dye Preparations

1μM Rhodamine 6G Dye Concentration (90:10)

  M1V1 = M2V2
  1μM (RG6)x 10mL = (92μM)V2    V2 = 109μL

1μM Rhodamine 6G Dye Concentration (50:50)

  M1V1 = M2V2
  1μM (RG6)x 10mL = (165μM)V2    V2 = 61μL

Hydrogel Pressure Testing Protocol

1. Heat a 9 in. Corning disposable, non-sterile Pasteur pipette using a Bunsen burner in order for the pipette to bend in various directions.
2. Select a hydrogel for pressure analysis and measure out ~ 0.1 grams of the sample.
3. Next, using a razor blade cut the hydrogel for testing into small cubes in order to fit into the Pasteur pippette
4. Once placing the sample in a Pasteur pipette, attach a ribber bulb to the top of the pipette, and allow 3mL of distilled H2O enter into the pipette by squeezing ribber bulb
5. Progressively squeeze the bulb in order to expel the 3mL of H2O and apply a pressure to the hydrogels – dispensing Rhodamine 6G dye (dye leaching)
6. Collect the expelled samples into a small 25mL beaker in order to fluorescence detection analysis

Hydrogel Pressure Samples Tested

Notes