Multifunctional nanoparticles are increasingly employed to improve biological efficiency in medical imaging, diagnostics, and treatment applications. However, even the most well-established nanoparticle platforms rely on multiple-step wet-chemistry approaches for functionalization often with linkers, substantially increasing complexity and cost, while limiting efficacy. Plasma dust nanoparticles are ubiquitous in space, commonly observed in reactive plasmas, and long regarded as detrimental to many manufacturing processes. As the bulk of research to date has sought to eliminate plasma nanoparticles, their potential in theranostics has been overlooked. Here we show that carbon-activated plasma-polymerized nanoparticles (nanoP(3)) can be synthesized in dusty plasmas with tailored properties, in a process that is compatible with scale up to high throughput, low-cost commercial production. We demonstrate that nanoP(3) have a long active shelf life, containing a reservoir of long-lived radicals embedded during their synthesis that facilitate attachment of molecules upon contact with the nanoparticle surface. Following synthesis, nanoP(3) are transferred to the bench, where simple one-step incubation in aqueous solution, without the need for intermediate chemical linkers or purification steps, immobilizes multiple cargo that retain biological activity. Bare nanoP(3) readily enter multiple cell types and do not inhibit cell proliferation. Following functionalization with multiple fluorescently labeled cargo, nanoP(3) retain their ability to cross the cell membrane. This paper shows the unanticipated potential of carbonaceous plasma dust for theranostics, facilitating simultaneous imaging and cargo delivery on an easily customizable, functionalizable, cost-effective, and scalable nanoparticle platform.