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
- In 50mL beaker, dissolve ~ 1.0g total of PVOH 146K or PVOH 130K along with clay additive selected in 25mL hot deionized H2O
- 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
- Cool solution for ~ 5 minutes, then remove the stir bar, and add PVOH clay sample to a blender.
- Afterwards, then add 35mL rather than 25mL of mineral oil to the sample in the blender.
- Blend sample solution prepared in blender for ~ 7 minutes on high to form a more homogeneous mixture / emulsion (creating a suspension of microspheres)
- 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)
- 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.
- After the addition of the dye and liquid nitrogen freezing, allow the solution to go through freeze / thaw crosslinking process for ~ 2-3 days
- 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
- Heat a 9 in. Corning disposable, non-sterile Pasteur pipette using a Bunsen burner in order for the pipette to bend in various directions.
- Select a hydrogel for pressure analysis and measure out ~ 0.1 grams of the sample.
- Next, using a razor blade cut the hydrogel for testing into small cubes in order to fit into the Pasteur pippette
- 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
- 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)
- Collect the expelled samples into a small 25mL beaker in order to fluorescence detection analysis
Hydrogel Pressure Samples Tested
90:10 PVOH MW 146K 110% CEC Lamponite w/ DMHXLBR Hydrogel
|
'
|
|
|
Pasteur Pipette Shape |
Amount of Hydrogel Used(g)
|
Pasteur pipette w/ no modifications |
0.1575
|
Pipette stem bent at slight angle < less than 90 degrees |
0.1134
|
Pipette stem bent at slight angle < 90 degrees beginning stem of pipette |
0.1397
|
Pipette w/ three pockets at top |
0.1039
|
Pipette bent twice in the stem |
0.1158
|
Pipette bent at top ≈ 90 degree angle w/ pipette sides almost touching |
0.1108
|
Pipette with a twist in middle |
0.0993
|
Pipette bent twice in the middle |
0.1416
|
Pipette w/ two pockets in the top |
0.1041
|
Pipette w/ top bent & sides almost touching = 90 degree angle |
0.1258
|
Plain Pasteur pipette w/ no modifications: Run #2 |
0.1210
|
Notes
|