A gulf presently lies between the nanoscale engineering of materials science on the one hand and the manipulation and understanding of evolved biological machinery on the other. In time that gulf will close: future industries will be capable of producing and controlling entirely artificial machines that integrate with, enhance, or replace our natural biological machines. Meanwhile biologists will be manufacturing ever more artificial and enhanced versions of cellular components, finding ways to make them better: evolution has rarely produced the best design possible for any given circumstance. Both sides will work towards one another and eventually meet in the middle.
Insofar as aging goes, a process of accumulating damage and malfunction in our biology, it is likely that this will first be successfully addressed and brought under medical control by producing various clearly envisaged ways to repair and maintain our cells just as they are: remove the damage, restore youthful function, and repeat as necessary. We stand much closer to that goal than the far more ambitious undertaking of building a better, more resilient, more easily repaired cell - a biology 2.0 if you like. That will happen, however. Our near descendants will be as much artificial as natural, and more capable and healthier for it.
The introduction of machinery to form a new human biology won't happen all at once, however, and it isn't entirely a far future prospect. There will be early gains and prototypes, the insertion of simpler types of machine into our cells for specific narrow purposes: sequestering specific proteins or wastes, or as drug factories to produce a compound in response to circumstances, or any one of a number of other similar tasks. If you want to consider nanoparticles or engineered assemblies of proteins capable of simple decision tree operations as machines then this has already happened in the lab:
Researchers [have] have made an important step towards creating medical nanorobots. They discovered a way of enabling nano- and microparticles to produce logical calculations using a variety of biochemical reactions. Many scientists believe logical operations inside cells or in artificial biomolecular systems to be a way of controlling biological processes and creating full-fledged micro-and nano-robots, which can, for example, deliver drugs on schedule to those tissues where they are needed.
Further, there is a whole branch of cell research that involves finding ways to safely introduce ever larger objects into living cells, such as micrometer-scale constructs. In an age in which the state of the art for engineering computational devices is the creation of 14 nanometer features, there is a lot that might be accomplished in the years ahead with the space contained within a 1000 nanometer diameter sphere.
Direct introduction of functional objects into living cells is a major topic in biology, medicine, and engineering studies, since such techniques facilitate manipulation of cells and allows one to change their functional properties arbitrarily. In order to introduce various objects into cells, several methods have been developed, for example, endocytosis and macropinocytosis. Nonetheless, the sizes of introducible objects are largely limited: up to several hundred nanometers and a few micrometers in diameter. In addition, the uptake of objects is dependent on cell type, and neither endocytosis nor macropinocytosis occur, for example, in lymphocytes. Even after successful endocytosis, incorporated objects are transported to the endosomes; they are then eventually transferred to the lysosome, in which acidic hydrolases degrade the materials. Hence, these two systems are not particularly suitable for introduction of functionally active molecules and objects.
To overcome these obstacles, novel delivery systems have been contrived, such as cationic liposomes and nanomicelles, that are used for gene transfer; yet, only nucleic acids that are limited to a few hundred nanometers in size can be introduced. By employing peptide vectors, comparatively larger materials can be introduced into cells, although the size limit of peptides and beads is approximately 50nm, which is again insufficient for delivery of objects, such as DNA origami and larger functional beads.
Here, we report a method for introducing large objects of up to a micrometer in diameter into cultured mammalian cells by electrofusion of giant unilamellar vesicles (GUVs). We prepared GUVs containing various artificial objects using a water-in-oil emulsion centrifugation method. GUVs and dispersed HeLa cells were exposed to an alternating current (AC) field to induce a linear cell-GUV alignment, and then a direct current (DC) pulse was applied to facilitate transient electrofusion.
With uniformly sized fluorescent beads as size indexes, we successfully and efficiently introduced beads of 1 µm in diameter into living cells along with a plasmid mammalian expression vector. Our electrofusion did not affect cell viability. After the electrofusion, cells proliferated normally until confluence was reached, and the introduced fluorescent beads were inherited during cell division. Analysis by both confocal microscopy and flow cytometry supported these findings. As an alternative approach, we also introduced a designed nanostructure (DNA origami) into live cells. The results we report here represent a milestone for designing artificial symbiosis of functionally active objects (such as micro-machines) in living cells. Moreover, our technique can be used for drug delivery, tissue engineering, and cell manipulation.
Cell machinery will be a burgeoning medical industry of the 2030s, I imagine. To my eyes the greatest challenge in all of this is less the mass production of useful machines per se, and more the coordination and control of a body full of tens of trillions of such machines, perhaps from varied manufacturers, introduced for different goals, and over timescales long in comparison to business cycles and technological progress. That isn't insurmountable, but it sounds like a much harder problem than those inherent in designing these machines and demonstrating them to be useful in cell cultures. It is a challenge on a scale of complexity that exceeds that of managing our present global communications network by many orders of magnitude. If you've been wondering what exactly it is we'll be doing with the vast computational power available to us in the decades ahead, given that this metric continues to double every 18 months or so, here is one candidate.