|Under Review - This lore is not technically yet official. Don't take it entirely as canon.|
Controlled bioprinting is the process by which layers of designed tissues, usually stemming from harvested pluripotent stem cells, are printed in such a manner to create a functional organic tissue. Modern growth and printing techniques allow for the creation of complex organs and organic systems with little-to-no evidence that they did in fact not develop "naturally". The cost, difficulty, and time of these processes varies significantly depending on the scale and extent of the procedure. This is due to the difficulty of providing organs or complex organisms all the necessary support whilst they are printed - for example, blood supply and waste removal.
A relatively common procedure throughout human space, the principles of bioprinting limbs or spare organs and then surgically implanting or attaching them to the patient upon completion have been well known for over a century. A patient who has lost a limb or is suffering from damage or failure of an organ can continue living their life to the best of their ability whilst a replacement is grown for them. In the case of the patient not having the high-detail scans which are usually periodically taken for those who have health insurance or live in areas where such scans are provided cheaply or free of charge, there are a variety of options. For limbs, or organs such as eyes or kidneys, scans can be taken of one and then mirrored, and doctored if necessary. Alternatively, scans can be taken from another similar individual and doctored to some degree to ensure that the limb is a sufficient shape and size - the actual organic matter will be printed and/or grown based on stem cells donated by the patient, so there is no worry of incompatibility.
What About Prosthetics?
Some individuals forgo replacing missing limbs or bodyparts with grown biological replacements and instead choose mechanical and cybernetic implants. These prostheses are often significantly cheaper and easier to source than biological variants, as well as granting a larger degree of customisation, both functionally and cosmetically. As a result, an increasingly large proportion of people opt for mechanical prosthetics for economic, cosmetic, functional reasons.
On of the most expensive, rare, and complex of bioprinting procedures is generally known as "resleeving". A resleeving operation consists of bioprinting and growing an entire functional body in stages, often in multiple parts and slowly combining them together. This is due to the necessity of swapping artificial support systems for real support systems as the procedure continues. For example, printing and testing a functional heart once the circulatory system is complete, but using artifical/assisted circulation in the meantime. On the scale of an entire body such requirements prove to be a logistical challenge. Once the body has been printed in its entirely, including the nervous system up to the brainstem, the patient's brain is finally attached.
The total process is often risky and time-consuming as a whole, as well as extremely expensive, with the final connection of the brain being the most dangerous and specialist step. Regardless, resleeving is common amongst some richer circles as a way to achieve functional "immortality of the body", allowing an individual of an advanced age to abandon their body and be implanted into a new one, which grants them possession of the organs and tissues of a much-younger them interfaced with their "original" brain. With good care and better medication, such an individual may be able to live for nearly a century and a half, maybe with multiple successive resleeving procedures, before their persistent brain finally succumbs to old age.
Resleeving can also be a common end-goal amongst people, especially those who are at odds with the concept of cloning, who would rather their brain was preserved after death. Those who cannot afford the operation often agree to cyborgification contracts so they may continue to live their lives to some degree, or alternatively purchase full-body prosthetics. Some are cryogenically frozen until such a time that their resleeving can be completed.
Finally, resleeving is also used to replace a body in instances where the patient has not suffered irreversable trauma or physical malady, where small-scale conventional treatments or directed genetic therapy would be too time-consuming or would have an inadequate effect. Common examples of this include patients opting for sexual reassignment or correction of extreme disorders caused during their childhood or development, including bone disorders such as dwarfism. Sometimes clinics are also willing to provide expensive custom cosmetic resleeving for non-medical cases, venturing into the realms of transhumanism. Such alterations are often heavily regulated by governments and professional ethics councils.
Cloning uses the same technology and works on the same basis, except instead of attaching an individuals brain at the end of the procedure, a new brain is grown based off of high-resolution imaging.