Warmer and process for promoting a biological reaction

A process for carrying out an in vitro biochemical reaction for preparing a cell suspension suitable for application to the skin of a patient, the process comprising:

• i. activating a warmer consisting of a hermetic plastic pouch containing a sodium acetate-saturated aqueous solution, the operation of which is based on an exothermic physical or chemical process,
• ii. bringing said warmer into contact with a container containing a solution comprising trypsin by placing the warmer and at least the lower part of the container in a cavity of a support,
• iii. placing a skin tissue sample comprising cells suitable for grafting to the skin of the patient in the solution comprising trypsin and incubating at from 30° C. to 37° C. for at least five minutes,
• iv. isolating the cells disassociated from the skin sample and suspending the cells in a solution, and
• v. filtering the solution of in step (iv) on a cell sieve, to thereby provide the cell suspension suitable for application to the skin of a patient.