Polymer freestanding membranes with permanent bipolar patterns are fabricated by "pyroelectrification". The thermal stimulation of periodically poled lithium niobate (PPLN) crystals simultaneously generates the pyroelectric effect, the glass transition of the polymer, and therefore the periodic electric poling of the polymer. The reliability of these membranes is demonstrated for applications under both dry and wet conditions, including cell patterning.

A simple and rapid process for multiscale printing of bioinks with dot widths ranging from hundreds of microns down to 0.5 μm is presented. The process makes use of spontaneous surface charges generated pyroelectrically that are able to draw little daughter droplets directly from the free meniscus of a mother drop through jetting ("p-jet"), thus avoiding time-consuming and expensive fabrication of microstructured nozzles. Multiscale can be easily achieved by modulating the parameters of the p-jet process. Here, it is shown that the p-jet allows us to print well-defined adhesion islands where NIH-3T3 fibroblasts are constrained to live into cluster configurations ranging from 20 down to single cell level. The proposed fabrication approach can be useful for high-throughput studies on cell adhesion, cytoskeleton organization, and stem cell differentiation.

In recent years, the use of probiotics in food and health has increased so much that usually market offers several functional fermented food or nutraceuticals containing probiotics, often also associated to prebiotics. Both in food industry and in pharmaceutics, it is very important the development and use of methodologies that quickly allow a precise overview about the microbial population present in a specific biological matrix, and to monitor over time any changes that it may undergo. In this work, we propose bio-speckle decorrelation as a tool for the fast evaluation of the effectiveness of microencapsulation as a preservation system. Although speckle grains are often treated as an impairment for imaging, they represent a precious source of information. Such information is rich enough to characterize bacterial dynamics in a fast and simple way suitable for applications in food science and industry. In fact, here we show that through bio-speckle decorrelation it is possible to quantify the shelf-time of alginate-encapsulated probiotic bacteria and their survival rate under simulated gastro-intestinal conditions.

Spiral shapes occur frequently in nature as in the case of snail shells or the cochlea - the auditory portion of the inner ear. They also inspire many technological devices that take advantage of this geometry. Here we show that μ-pyro-electrospinning is able to control whipping instabilities in order to form spiralling fibres (down to 300 nm thick) directly on a support with true microscale regularity. The results show that polymer concentration plays a key role in producing reliable and long spirals. We investigate the cell response to these spiral templates that, thanks to their true regularity, would be useful for developing innovative cochlea regeneration scaffolds.

Biofilms are detrimental to human life and industrial processes due to potential infections, contaminations, and deterioration. Therefore, the evaluation of microbial capability to form biofilms is of fundamental importance for assessing how different environmental factors may affect their vitality. Nowadays, the approaches used for biofilm evaluation are still poor in reliability and rapidity and often provide contradictory results. Here, we present what we call biofilm electrostatic test (BET) as a simple, rapid, and highly reproducible tool for evaluating in vitro the ability of bacteria to form biofilms through electrostatic interaction with a pyroelectrified carrier. The results show how the BET is able to produce viable biofilms with a density 6-fold higher than that on the control, after just 2 h incubation. The BET could pave the way to a rapid standardization of the evaluation of bacterial resistance among biofilm-producing microorganisms. In fact, due to its simplicity and cost-effectiveness, it is well suited for a rapid and easy implementation in a microbiology laboratory.