Clay-based drug-delivery systems: what does the future hold?

Clays for drug delivery have been used from ancient time due to the large availability of clay minerals and their unprecedented properties. The empirical use of nanoclays from the past is converted in a stimulating scientific task aimed at building up nanoarchitectonic vehicles for drug delivery in a targeted and stimuli-responsive fashion. Here the historical aspects are discussed; next the modern examples of applications of different clay-based materials are discussed. A special focus is given to halloysite clay nanotubes, which are an emerging and very promising nanomaterial for drug-delivery purposes due to its special morphology and unique chemical properties. Advantages and limitations of these natural nanomaterials are critically discussed pointing out the future perspectives and directions for further research

Fabrication of living cellosomes of rod-like and rhombohedral morphologies based on magnetically responsive templates

We have developed hollow multicellular structures by polyelectrolyte-mediated self-assembly of yeast cells around magnetically responsive inorganic templates and have demonstrated the cells' viability in the produce

A direct technique for preparation of magnetically functionalised living yeast cells

A direct technique for preparation of magnetically functionalised yeast cells by using polyelectrolyte mediated deposition of magnetite nanoparticles is reported. We demonstrate that the cells preserve their viability after the magnetite deposition and show that the magnetic nanoparticles form a multilayered coating on the outer side of the yeast cell's wall. We applied our technique to produce magnetically functionalised yeast cells expressing green fluorescent protein (GFP) under the control of RAD54-GFP reporter and demonstrated that their fluorescence emission is not influenced by the presence of magnetite-polyelectrolyte composite coating. We show that the individual cells can be successfully manipulated by an external magnetic field which can be used for their deposition, holding and subsequent removal from microfluidic devices for genotoxicity and cytotoxicity biosensor applications. Our technique for direct magnetization of cells can find many other biotech applications including biosensors, bioreactors and bioseparation. © 2011 The Royal Society of Chemistry

Artificial multicellular assemblies from cells interfaced with polymers and nanomaterials

In this chapter we review the recent developments in fabrication of multicellular assemblies from cells modified with polymers and nanomaterials. We focus on the specific properties of such “cyborg” cells that allow a variety of new methods to be used for their assembly into multicellular structures with functions rather different from those of the original cells. We discuss template and external-field-mediated assembly of modified cells as well as various techniques for preparation of tissue spheroids and polyelectrolyte-mediated cell assemblies. Numerous applications of such cell assemblies in tissue engineering, bioprinting, biosensing and bioelectronics are outlined and commented on throughout the chapter

Rapid and direct magnetization of GFP-reporter yeast for micro-screening systems

Saccharomyces cerevisiae containing fluorescent markers are ideal candidates for applications in microfluidic screening systems as fluorescence signal is emitted without the need of additional reagents. Here we develop a method for magnetic functionalisation of such cells which allows their handling and immobilization in micro-screening devices. After exposure of the magnetized GFP-reporter yeast (GreenScreen™) to a genotoxic compound, the fluorescence emission was detected using fluorescent spectrometer and an Epi-fluorescent microscope. Results demonstrate that GFP production and fluorescence emission is not altered by their magnetic functionalization, indicating its potential employment on biosensors, bioreactors and micro-screening studies. © 2009 Elsevier B.V