A method for treating skin in a subject is disclosed. The method comprises the steps of administering a stem cell composition into a target body site in the subject by subcutaneous, intradermal or topical delivery, and contacting the target body site with a treatment device designed for introducing CO2 into subcutaneous tissue, wherein the CO2 and the stem cell composition are provided in an amount effective for treating a skin-related disorder or improving the condition of skin. Also disclosed is a method for generating induced pluripotent stem cells (iPSCs) in a subject.
