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.

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.

Natural halloysite clay tubules were studied for their potential use as miniature biocompatible containers that can be loaded with antiseptics followed by their slow and controlled release. Brilliant green was loaded into 15 nm diameter halloysite lumen at 15 wt% and provided sustained release over six hours.Formation of a benzotriazole-copper coating on halloysite nanotubes allowed additional encapsulation providing for more sustained release from 50 to 200 hours. Antibacterial efficiency of the brilliant green in clay nanotubes was tested on Staphylococcus aureus cultures and antibacterial action extended up to 72 hours was demonstrated. Sustained release of amoxicillin and iodine from halloysite tubes was also demonstrated.

Halloysites as tubular alumosilicates are introduced as inexpensive natural nanoparticles to form and stabilize oil–water emulsions. This stabilized emulsion is shown to enable efficient interfacial catalytic reactions. Yield, selectivity, and product separation can be tremendously enhanced, e.g., for the hydroformylation reaction of dodecene to tridecanal. In perspective, this type of formulation may be used for oil spill dispersions. The key elements of the described formulations are clay nanotubes (halloysites) which are highly anisometric, can be filled by helper molecules, and are abundantly available in thousands of tons, making this technology scalable for industrial applications