{"action": "prepare", "output": "", "reagent": ["human periodontal ligament cells"]}
{"action": "maintain", "output": "", "reagent": ["MEM-\u03b1"], "volume": ["approximately 10 mL"]}
{"action": "observe", "output": ""}
{"action": "rinse", "output": "", "volume": ["three to six"]}
{"action": "wash", "output": "", "reagent": ["PBS"], "times": ["2\u20133 times"]}