User:Allison K. Alix/Notebook/CHEM-581/2013/03/27

Experimental Chemistry

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Objectives -Convert bound ULVs into a single bilayer coating the microgels -Observe hydrogels containing dye under microscope -Prepare hydrogels containing new pH sensitive indicators Procedures Part 1: Finish preparing liposome coated hydrogels 1) Complete five freeze-thaw vortexes using liquid nitrogen on hydrogel-liposome solution(Freeze for 30 seconds or until frozen, thaw for 30 seconds or until thawed and vortex for 30 seconds. Repeat) 2) Remove unbound ULVs by centrifuging at 4000 rpm for 5 minutes 3) Resuspend in 25mM tris-HCl buffer Part 2: Preparing a concentration gradient of R6G in hydrogels 1) Add the following volumes of 1mM R6G to 2mg PVOH hydrogels in 1.5mL phosphate buffer: 10μL, 15μL, 20μL, 25μL, 30μL, 35μL 2) Allow absorption of dye for 48 hours Part 3: Preparing pH sensitive hydrogels 1) Centrifuge hydrogel solutions containing methyl red and bromophenol blue prepared on 3/22 2) Collect supernatant and add 1mL phosphate buffer 3) Repeat to colelct a total of 3 supernatants for each solution 4) Collect UV-Vis spectra for each supernatant as well as stock solution to observe the amount of dye absorbed by the hydrogel 5) Observe pH changes of hydrogels w/ indicator. Data We were not able to view the hydrogels under the microscope (maintenance issues) This will be completed at antoher time. References Lipogels: Single-Lipid-Bilayer-Enclosed Hydrogel Spheres Qasim Saleem,†,§,|| Baoxu Liu,§,‡,||Claudiu C. Gradinaru,*,§,‡ and Peter M. Macdonald