User:Alexander Cvitan/Notebook/Experimental Biological Chemistry Lab/2014/01/29

Biomaterials Design Lab

Main project page Previous entry      Next entry

Purpose Make stock buffer solutions at specific pH's. See the effect of the addition of these buffer solutions on Lysozyme AuNP fiber formation. Procedure Mix all test tubes in order to re-suspend the fibers in the solution. (Not to dissolve but to evenly distribute the fibers in the solution.) Take 1 mL of solution from each test tube and place it in a separate 1.5 mL tube. (These aliquots will initially be used in order test each variable.) Chelators Creating Stock Solutions of Chelators Note 2, 2 bipyridyl was replaced with 2, 2 bipyridine. The only difference between the two are the chirality is different. It still functions as chelator. Adding Chelators to Lysozyme-AuNP Solutions Add 0.5 mL of each chelator stock solution to each 1.5 mL aliquot. Record effect of chelator on AuNP's. pH How we made each 1 M Buffer Solution Please note that all of the following dilutions were calculated via an online buffer calculator found [HERE.] Citric Acid: pH - 3 Add 42.02 g of citric acid in 180 mL distilled water. Titrate to pH 3.0 with monovalent strong acid/base if necessary. Fill up to 200 mL with distilled water. Phosphate: pH - 7 Add 0.0908 mol of sodium phosphate monobasic to 0.1091 mol of sodium phosphate dibasic. Fill up to 200 mL with distilled water. Tris: pH - 9 Dissolve 24.228 g Tris base in 180 mL distilled water. Titrate to pH 9.0 with monovalent strong acid/base if necessary. Fill up to 200 mL with distilled water. MES: pH - 5.21 (Note Cannot Get Down to 5) Dissolve 39.04 g MES in 180 mL distilled water. Titrate to pH 5.2 with monovalent strong acid/base if necessary. Fill up to 200 mL with distilled water. HEPES: pH - 7 Dissolve 47.66 g HEPES in 180 mL distilled water. Titrate to pH 7 with monovalent strong acid/base if necessary. Fill up to 200 mL with distilled water. CHES: pH - 9 Dissolve 41.46 g CHES in 180 mL distilled water. Titrate to pH 9 with monovalent strong acid/base if necessary. Fill up to 200 mL with distilled water. Adding Buffers to Lysozyme-AuNP Solutions Dilute the 1 M solutions to 100 mM, 10 mM, and 1 mM. Add 1 mL of each to the lysozyme-AuNP solutions. Let sit overnight and record results. Looking at the AuNP's None of the 50:1 ratio AuNP's formed fibers. As a result they were remade because one of the stocks must have been slightly less concentrated. Carly re-did the calculations and remade more 50:1 AuNP's. Nonetheless the chelators and and buffers were added to the other ratios made to see the effect. We will see the effect on the 50:1 ratio tomorrow. Ratios 110:1 and 40:1 had chelator and buffer added to different aliquots. Their was no reaction immediately; however, solutions were left overnight.