1. A bioprinter comprising: a) one or more printer heads, wherein each printer head comprises a means for receiving and holding at least one cartridge, and wherein each cartridge comprises a deposition orifice and a bio-ink, the bio-ink comprising a solid or semi-solid composition comprising living cells; b) a means for dispensing the bio-ink of a selected cartridge by application of pressure to extrude the bio-ink of the selected cartridge through the deposition orifice; c) a means for determining a position of the selected cartridge in space; and d) a programmable computer processor for regulating the dispensing of the bio-ink communicatively coupled to the means for determining a position of the selected cartridge and the means for dispensing the bio-ink.