Earlier this month, I pointed out a series of articles that examined how we might go about developing the means to gradually replace neurons in the brain with nanomachines that serve the same purpose and integrate fully with the remaining natural neurons. If the pace of that process is slow, on a par with natural levels of neurogenesis and cell turnover, then we could argue that you remain you even though the end result is a completely artificial brain: the self is preserved.
This sort of process is a necessary precondition to live for much longer than a few thousand years following the development of rejuvenation biotechnology that can indefinitely prolong healthy, youthful life. Accidents happen, and the best way to reduce the chance of a fatal accident to negligible levels is to switch out the body and brain for more durable machinery.
Following on from that, here is a consideration of some of the details of replacing just portions of a cell with artificial components that perform the same function, but are immune by design to the degraded function known to occur in aging:
In this essay I argue that technologies and techniques used and developed in the fields of Synthetic Ion Channels and Ion-Channel Reconstitution, which have emerged from the fields of supramolecular chemistry and bio-organic chemistry throughout the past 4 decades, can be applied towards the purpose of gradual cellular (and particularly neuronal) replacement to create a new interdisciplinary field that applies such techniques and technologies towards the goal of the indefinite functional restoration of cellular mechanisms and systems.
In earlier essays I identified approaches to the synthesis of non-biological functional equivalents of neuronal components (i.e., ion-channels, ion-pumps, and membrane sections) and their sectional integration with the existing biological neuron. It has only recently come to my attention that there is an existing field emerging from supramolecular and bio-organic chemistry centered around the design, synthesis, and incorporation/integration of both synthetic/artificial ion channels and artificial bilipid membranes (i.e., lipid bilayer). The potential uses for such channels commonly listed in the literature have nothing to do with life-extension, however, and the field is, to my knowledge, yet to envision the use of replacing our existing neuronal components as they degrade (or before they are able to).
I argue here that the very technologies and techniques that constitute the field (Synthetic Ion Channels and Ion-Channel/Membrane Reconstitution) can be used towards the purposes of indefinite longevity and life-extension through the iterative replacement of cellular constituents so as to negate the molecular degradation they would have otherwise eventually undergone.