Fig. 7.

Distinct configurations of the skin patch. Upon explantation, an in vivo unit square retracts to a square of dimensions 0.83 × 0.83 due to prestrain. Upon expansion, the unit square transforms into a 1.40 × 1.34 rectangle, with greater stretch in the direction parallel to the midline. During expansion, the patch grows naturally by 1.24 × 1.20. The final size of the expanded patch includes natural and expander-induced growth, which turns a 1.03 × 1.00 naturally grown patch into the final 1.34 × 1.18 ex vivo patch.