Materials:
HA (MW 50 kDa from Lifecore)
Methacrylic anhydride
5N NaOH (to adjust pH)
Dialysis materials
Procedure:
1) Add HA at 1 wt% to deionized water
2) Adjust the pH to 8
i. put this in a multineck round bottom flask with 100 or 200 ml of the solution and put a pH probe in while the solution is stirring
3) Add the methacrylic anhydride (about 2 ml per 200 ml of the HA solution) slowly to the solution
ii. As the methacrylic anhydride is added, there will be quite a bit of fluctuation in the pH
4) Adjust the pH intermittently to maintain a pH of 8
5) Leave on ice for several hours while you monitor every 15 minutes or so and then if the pH seems to be stable
6) Place in the cold room stirring overnight
7) Dialyze (at least 2 days with several changes of water)
8) Lyophilize (takes a few days due to the large volume)
9) Store frozen in the powder form.