Keith Causey

Keith Causey is an engineer and the Engineering Generalist of Molecular Reality Corporation, an American company that builds instruments for sensing single molecules and particles as they pass through small holes.^[1] Before his work for the company he built laboratory devices for aging research at the SENS Research Foundation in California. One of them, a computer-controlled pump that swapped blood between pairs of mice through a catheter, was the instrument behind a 2016 paper in Nature Communications, a journal of the Nature Portfolio, on what old blood does to young tissue.^[2]

At Molecular Reality he has worked on the company's hardware since before it was incorporated, from early mechanical nanopore prototypes to fluidics and the drive of the Molecular Aquarium.^[1] The company's guide for visitors names him with the AI lead: "Jade and Keith build alongside him, in the lab and in the code".^[3]

The SENS Research Foundation, based in Mountain View, California, funded research toward repairing the damage that accumulates with age. His two papers indexed in PubMed come from that work, and both describe machines that take blood out of a mouse, do something to it, and put it back.

The first, in Rejuvenation Research in 2010, went after a kind of immune cell that piles up in old animals: cytotoxic T cells that carry a marker called KLRG1 and no longer respond as young cells do. The authors linked antibodies against the marker to magnetic nanoparticles, filtered the tagged cells out of blood with magnets, and then "constructed a device that does this automatically". In aged mice it cut the count of these cells, relative to all cells of their type, by a factor of 7.3, "reaching a level typically seen only in very young animals".^[4]

The second paper answered a question raised by heterochronic parabiosis, in which an old and a young mouse are joined surgically so that they share a circulation. A 2005 study in Nature had found that the muscle stem cells of old mice joined to young ones recovered much of their youthful ability to repair injury.^[5] Parabiosis shares organs as well as blood, though, and it cannot be undone at will, so the authors, at the University of California, Berkeley, and the SENS Research Foundation, replaced the surgery with a machine.^[2] According to the paper's statement of contributions, Causey "engineered the small animal exchange device".^[2]

The device was a computer-controlled circuit of microfluidic peristaltic pumps attached to a single catheter in the jugular vein. A mouse holds only about 5 to 8 percent of its weight in blood, and no more than about 10 percent can safely be taken at once, about 150 µL from a 30 g mouse. The protocol therefore swapped blood in small doses: 15 exchanges of 150 µL, with 30 seconds between giving and taking, repeated once within 24 hours, which the authors estimated mixed the two animals' blood to about 90 percent. Nearly all the animals survived.^[2]

The results, published on November 22, 2016, were titled "A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood". Within days old blood held back the repair of muscle, the regeneration of liver and the birth of new neurons in the hippocampus of young mice, and its harm was generally larger than the benefit young blood gave old mice.^[2] Neuroscience News headlined its report "Young Blood Does Not Reverse Aging in Old Mice".^[6] The same laboratory later turned to diluting old plasma with saline and albumin, in a 2020 study of plasma exchange in mice.^[7]

The device's peristaltic pumps moved 150 µL at a time. The pump module of the company's MR1 Nanopore Reader design, also peristaltic, is limited to between 0.5 and 150 µL a minute.^[2][8][1]

Causey had known Kent Kemmish for years before the company existed. By early 2015 the two were working out how to digitize the output of a picoammeter, the instrument that measures the small currents through a pore, three years before demonpore, inc., the company's first incarnation, was incorporated.^[1] The company credits him with designing and building its early mechanical nanopore prototypes and with fluidics and CAD for its MR1 work, and calls him a roboticist.^[1]

In 2020 he worked on the mechanics of the Molecular Aquarium, a silicon chip on which a moving plate selects one pore at a time from an array, including the motor and gearing of its drive.^[1] In 2021 he drew up a modified procedure for making pores by controlled dielectric breakdown, in which graphene was to be mounted over microfabricated chips and centered on them under a microscope.^[1] He later worked on files for the Burnerphone, the company's compact unit for making pores by breakdown.^[1]

Kemmish gave him the title Engineering Generalist in 2026.^[1] Of the nine character classes in the company's role-playing game, two divide its engineering between them: MechE for "hardware/fluidics" and Sparky for "electrical engineering".^[9] His work at the company has covered both.^[1]

• Rebo, J.; Causey, K. (2010). "Whole-animal senescent cytotoxic T cell removal using antibodies linked to magnetic nanoparticles". Rejuvenation Research 13 (2-3): 298-300. doi:10.1089/rej.2009.0964. PMID 20426617.
• Rebo, J. et al. (2016). "A single heterochronic blood exchange reveals rapid inhibition of multiple tissues by old blood". Nature Communications 7: 13363. doi:10.1038/ncomms13363. PMID 27874859.

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