Wireless nanotechnologies light up the next frontier in cell Calcium signalling

Calcium ions impact nearly every aspect of cellular life, playing crucial roles as secondary messengers in regulation of neurotransmission, cell proliferation, migration and differentiation processes, intracellular homeostasis, long-distance signal propagation and stimuli physiological response. Despite its key-role, available techniques to study and selectively regulate Ca2+ signalling largely rely on chemical and electrical approaches, which often cannot ensure the necessary spatial and temporal resolution, specificity, modulation and reversal capability. In this context, Ca2+ modulation based on physical stimuli, such as magnetic, mechanical and optical tools, are emerging ass promising innovative solutions. Here, we focus our attention on a subclass of these approaches, namely wireless-activated techniques, and on functional materials able to act as non-invasive transduction elements. We present an overview of most recent outcomes in the field, and we critically evaluate their advantages and drawbacks. This work is mainly directed to the material science community, but hopefully it will provide a useful perspective also to the broader readership of biotechnologists, physiologists and clinicians.

Spatial characteristics to calcium signalling; the calcium wave as a basic unit in plant cell calcium signalling

Many signals that modify plant cell growth and development initiate changes in cytoplasmic Ca 2+ . The subsequent movement of Ca 2+ in the cytoplasm is thought to take place via waves of free Ca 2+ . These waves may be initiated at defined regions of the cell and movement requires release from a reticulated endoplasmic reticulum and the vacuole. The mechanism of wave propagation is outlined and the possible basis of repetitive reticulum wave formation, Ca 2+ oscillations and capacitative Ca 2+ signalling is discussed. Evidence for the presence of Ca 2+ waves in plant cells is outlined, and from studies on raphides it is suggested that the capabilities for capacitative Ca 2+ signalling are also present. The paper finishes with an outline of the possible interrelation between Ca 2+ waves and organelles and describes the intercellular movement of Ca 2+ waves and the relevance of such information communication to plant development.