The present invention is directed to a dermal micro-organ, wherein said dermal micro-organ is an explant of living tissue consisting essentially of a plurality of dermal components and not including epidermal layers, which retains the micro-architecture and three dimensional structure of the dermal tissue from which it is derived, having dimensions selected so as to allow passive diffusion of adequate nutrients and gases to cells of said dermal micro-organ and diffusion of cellular waste out of said cells so as to minimize cellular toxicity and concomitant death due to insufficient nutrition and accumulation of waste in said Dermal micro-organ, wherein a dimension of length is 5-100 mm.