Introduction: Natural and biocompatible clay nanotubes are among the best inorganic materials for drug nanoformulations. These halloysite tubes with SiO2 on the outermost surface have diameter of c...

Here we investigated the toxicity of halloysite clay nanotubes in vivo employing a Caenorhabditis elegans nematode as a model organism. Using enhanced dark-field microscopy and physiological tests, we found that halloysite is localised exclusively in the alimentary system and does not induce severe toxic effects on nematodes.

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.