Microworms swallow the nanobait: the use of nanocoated microbial cells for the direct delivery of nanoparticles into Caenorhabditis elegans.

The application of in vivo models in assessing the toxicity of nanomaterials is currently regarded as a promising way to investigate the effects of nanomaterials on living organisms. In this paper we introduce a novel method to deliver nanomaterials into Caenorhabditis elegans nematodes. Our approach is based on using nanoparticle-coated microbial cells as "nanobait", which are ingested by nematodes as a sole food source. We found that nematodes feed on the nanocoated bacteria (Escherichia coli) and microalgae (Chlorella pyrenoidosa) ingesting them via pharyngeal pumping, which results in localization of nanoparticles inside the digestive tract of the worms. Nanoparticles were detected exclusively inside the intestine, indicating the efficient delivery based on microbial cells. Delivery of iron oxide nanoparticles results in magnetic labelling of living nematodes, rendering them magnetically-responsive. The use of cell-mediated delivery of nanoparticles can be applied to investigate the toxicity of polymer-coated magnetic nanoparticles and citrate-capped silver nanoparticles in Caenorhabditis elegans in vivo.

Cyborg cells: functionalisation of living cells with polymers and nanomaterials.

Living cells interfaced with a range of polyelectrolyte coatings, magnetic and noble metal nanoparticles, hard mineral shells and other complex nanomaterials can perform functions often completely different from their original specialisation. Such "cyborg cells" are already finding a range of novel applications in areas like whole cell biosensors, bioelectronics, toxicity microscreening, tissue engineering, cell implant protection and bioanalytical chemistry. In this tutorial review, we describe the development of novel methods for functionalisation of cells with polymers and nanoparticles and comment on future advances in this technology in the light of other literature approaches. We review recent studies on the cell viability and function upon direct deposition of nanoparticles, coating with polyelectrolytes, polymer assisted assembly of nanomaterials and hard shells on the cell surface. The cell toxicity issues are considered for many practical applications in terms of possible adverse effects of the deposited polymers, polyelectrolytes and nanoparticles on the cell surface.

Interfacing multicellular organisms with polyelectrolyte shells and nanoparticles: a Caenorhabtidis elegans study.

We report the surface modification of microscopic live multicellular nematodes Caenorhabtidis elegans with polyelectrolyte multilayers (pure and doped with 20 nm gold nanoparticles) and the direct magnetic functionalization of nematodes with biocompatible magnetic nanoparticles. Magnetically functionalized "ironoxideclad" nematodes can be effectively separated and moved using an external magnetic field. The surface-functionalized nematodes preserve their viability and reproduction.

Hybrid cellular-inorganic core-shell microparticles: encapsulation of individual living cells in calcium carbonate microshells.

We report the fabrication of hybrid cellular-inorganic core-shell microparticles obtained by encapsulation of individual living yeast cells Saccharomyces cerevisiae in calcium carbonate microshells and demonstrate the viability of the encapsulated cells. Our method is based on the direct precipitation of calcium carbonate on the cell walls of yeast cells. Resulting hybrid microparticles consist of single yeast cells coated with semipermeable inorganic microshells, which resemble the original ellipsoid shapes of yeast cells, exhibit negative zeta-potential, and have micrometer-thick calcium carbonate walls. The combination of the functional properties of living cells and calcium carbonate microshells promises a wide area of applications of these hybrid core-shell microparticles in the development of novel materials.