Index
PLLA / PLGA Polymer Film Fabrication
Equipment and Materials
18 mm diameter glass coverslips
PLGA, PLLA - 50 mg/mL in chloroform
black level table and leveling device
1 mL glass pipettes
vacuum oven
razor blade and tweezers
aluminum foil tape
Safety
1. Chloroform is a very volatile solvent. Its risk codes are given as “Harmful” and “Dangerous.” It is also a known carcinogen in animals.
· The Chemical Toxicity and Risk Information as well as the glove recommendations for Heavy Exposure and Intermittent Exposure are included with the protocols.
· In this protocol, you will be handling very small volumes of chloroform. Single (or double) disposable nitrile gloves are appropriate. Wear disposable nitrile gloves at all times.
· Do NOT breathe the vapors. ALL work (mixing, measuring, film fabrication, film drying, etc.) MUST be conducted in the hood.
· Wear a lab coat with long sleeves to protect against splashes on your arms.
· If you spill any chloroform or chloroform mixture on your hands, immediately remove your gloves and wash your hands. If you spill chloroform on another part of your body, wash that area immediately.
2. Wear safety glasses at all times.
3. When removing the films from the glass coverslips, you may need to use a razor blade. Use tweezers to hold the coverslip so that your fingers are not near the blade. THINK about what you are doing so that you do not cut yourself.
4. All glass waste (coverslips, pipettes) must be disposed of in special glass waste containers.
Instructor Preparation
1. Dissolve PLLA or PLGA in chloroform to 50 mg/mL (e.g. 250 mg polymer in 5 mL) in glass jar with screw top. Ensure that polymer is completely dissolved; this may take up to 1 hour.
Procedure for Film Fabrication
1. Set black level table in chemical fume hood. Ensure that table is level before proceeding; adjust if necessary.
2. Place coverslips on level table.
3. Open hood shield fully.
4. NOTE: Work with Dr. Saterbak or a T.A. when you first begin this process to refine your technique! Using a 1 mL glass pipette, deposit/spread 150 mL of polymer solution onto each glass coverslip.
· First drop a circle of the polymer solution to define the outer edge of the coverslip.
· Next fill in the circle with additional solution.
· Do not exceed 150 mL of polymer solution.
· Discard coverslip if polymer spills over edge of coverslip.
5. Allow chloroform to evaporate for a minimum of 10 minutes.
6. If the film dries clear and level, you may use this film in subsequent experiments. If not, you will need to make an additional film.
7. Place films in TC-treated 12-well plates for storage. Leave films in hood to air dry until the end of the afternoon in lab.
8. Dry films in vacuum oven for a minimum of 24 hrs. Films may stay in the vacuum oven for several days. See instructions on how to operate vacuum oven.
9. Clean-up materials and supplies.
NOTE: When preparing films for the degradation study, it is recommended that you make 3-4 extra films of each polymer type. You will likely destroy films during polymer casting and film removal (below).
1. Remove films from vacuum oven.
2. Add 3 mL of deionized water to each well. Allow films to soak for 90 min.
3. Cut aluminum foil tape into circles that fit snuggly into the bottom of the wells of a 12-well plate. Attach aluminum foil circles to the bottom of the wells.
4. Carefully remove films from coverslip using razor blade and tweezers.
NOTE: The film must be removed in one piece. It is OK if the glass coverslip breaks, as long as the film does not. Discard films that are ripped or torn. It is OK if the film is a little bit stretched.
5. Place films on foil-covered wells.
6. Leave films in chemical fume hood to air dry until the end of the afternoon in lab.
7. Dry films in vacuum oven for a minimum of 24 hrs. Films may stay in the vacuum oven for several days. See instructions on how to operate vacuum oven.