The needle phobia includes the fear for all the medical procedures involving injections and the use of syringes. In some cases, the fear of needles is so great even before the indentation, inducing a serious of psychological complication and causing difficulties with managing strong emotion and sensation. The design and development of technological solutions that could overcome this problem is very interesting from a social and industrial point of view. In this paper, we focus on the fabrication of polymeric micro-needles as a user-driven device able to hinder needle-phobia for drug-delivery and sensing purposes. We focus on the fabrication of polymeric needle that in case of use for children appear as a friendly solution, we will focus on the fabrication of a sort of patch that could be easily applied avoiding all the invasive procedures usually involved in case of conventional syringes. We are confident that the children- driven device could open to application also for adults or elderly people involved by the needle phobia or more in general exhausted of the conventional therapies.

Oil bodies (OBs) dispersed in an aqueous medium form a natural emulsion with high physical and microbiological stability. This work was focused on the development of a new protocol for extracting OBs from olive paste, through the extraction of an olive oil body cream (OOBC) with a yield of about 43% (wt/wt) in approximately 2 h. The proximate analysis revealed the presence of moisture, lipids and proteins as well as the contents of polyphenols and flavonoids, and the antioxidant powers were determined. The rheological and tribological performances of the OOBC were evaluated. Moreover, we measured a size distribution in the range of 0.7-1.7 m, by using a standard optical microscope. The results have demonstrated clearly that the OOBC extracted from the olive paste can be used as a functional and vegan ingredient in food emulsions.

The pyro-electrohydrodynamic jet (p-jet) printing technology has been used for the fabrication of confined assemblies of gold nanoparticles with a round shape and a diameter ranging between 100 and 200 mu m. The surface-enhanced Raman spectroscopy (SERS) performance of the p-jet substrate was evaluated by using Rhodamine 6G (R6G) as a reference. The results demonstrate that this kind of SERS substrate exhibits strong plasmonic effects and a significant reproducibility of the signal with a coefficient of variation below 15%. We tested the signal behavior also in case of the bovine serum albumin (BSA) as a model analyte, to demonstrate the affinity with biomolecules. Strong SERS activity was measured also for BSA across the whole spot area. The spectral patterns collected in different locations of the sensing area were highly reproducible. This observation was substantiated by multivariate analysis of the imaging datasets and opens the route towards a potential application of this kind of SERS substrate in biosensing.

Here we describe the fabrication of smart biodegradable and biocompatible micro-needles for combining the drug delivery with advanced sensing properties that would be the base for advanced telemedicine tools.

The direct and rapid formation of a precise pattern of metallic nanoparticles (NPs) supported and/or embedded in a flexible polymeric substrate is not easy to achive. However, the development of simpler and more reliable procedures is still highly desirable. This paper presents an innovative technique, simple, cheap, and robust, for producing a self-supported sheet of polydimethylsiloxane (PDMS) embedding periodic arrays of clusters of nickel nanoparticles (NiNPs). The method uses the pyroelectric effect in a periodically poled lithium niobate (PPLN) crystal for producing a surface charge template able to address the patterning of the NPs by applying a simple thermal stimulation. The key advantages are rapidity, single-step, and electrode-free operation. The reliability of the technique is demonstrated for different geometries that are called here "dots" and "grid" and for three different periods 50, 200, and 400 mu m. The resulting sheets are attractive for both their flexibility and magnetic properties that can be used for detection, entrapment, and/or patterning of micro- and nanoparticles in various fields such as microfluidics and biomedicine.

The ability of a bacterial strain to form a biofilm is strictly related to its pathogenicity. Bacterial adherence and early biofilm formation are influenced by chemical, physical and biological factors that determine their pathogenic properties. We recently presented in literature the ability of pyro-electrified polymer sheets to promote rapid biofilm formation, based on what we called biofilm electrostatic test (BET) carriers. Here we performed a step forward by presenting a comprehensive characterization of the BET methodology through a quantitative evaluation of the biomass on the BET-carrier in the very early stages of incubation. Two bacterial suspensions of Escherichia coli were added to the surface of the BET-carrier, with one order of magnitude difference in initial optical density. The biofilms were stained at different incubation times, while the crystal violet assay and the live/dead reaction kit were used for evaluating the biomass and the viability, respectively. The BET-carrier systematically promoted a faster biofilm formation even in case of very diluted bacterial concentration. The results suggest that the BET-carrier could be used for evaluating rapidly the ability of bacteria to form biofilms and thus their inclination to pathogenicity, thanks to the challenging acceleration in biofilm formation.

The demand for sensors capable of measuring low-abundant collagen in human fluids has highly increased in recent years. Indeed, collagen is expected to be a biomarker for chronic diseases and could monitor their progression. Here we show detection of highly diluted samples of collagen at picogram level thanks to an innovative pyro-electrohydrodynamic jet (p-jet) system. Through the intense electric fields generated by the pyroelectric effect in a ferroelectric crystal, the collagen solution was concentrated on a small area of a slide that was appropriately functionalized to bind proteins. The collagen molecules were labeled by an appropriate fluorophore to show how the number of tiny droplets influences the limit of detection of the technique. The results show that the p-jet is extremely promising for overcoming the current detection limits of collagen-based products in human fluids, performing 10 times better than the enzyme-linked immunosorbent assay (ELISA) and thus paving the way for the early diagnosis of related chronic diseases.

The effective detection of low-concentrated molecules in small volumes represents a significant challenge in many sectors such as biomedicine, safety, and pollution. Here, we show an easy way to dispense liquid droplets from few mu l volume (0.2-0.5 mu l) of a mother drop, used as reservoir, by using a pyro-electrohydro-dynamic jetting (p-jet) dispenser. This system is proposed for multi-purpose applications such as printing viscous fluids and as a biosensor system. The p-jet system is based on the pyroelectric effect of polar dielectric crystals such as lithium niobate (LN). The electric field generated by the pyroelectric effect acts electro-hydrodynamically on the sample of liquid, allowing the deposition of small volumes. The p-jet approach allows to obtain the dispensing of drops of very small volumes (up to tenths of a picoliter) avoiding the use of syringes and nozzles generally used in standard technologies. The reliability of the technique as a biosensor is demonstrated both in the case of oligonucleotides and in a sample of clinical interest, namely gliadin. The results show the possibility of detecting these biomolecules even when they are low abundant, i.e. down to attomolar. The results show a marked improvement in the detection limit (LOD) when compared with the conventional technique (ELISA). Moreover, it has been presented the possibility of using the p-jet as a useful tool in the detection of biomarkers, present in the blood but currently not detectable with conventional techniques and related to neurodegenerative diseases such as Alzheimer.

Pyro-electrohydrodynamic jet printing (p-jet) has been used to fabricate a nanostructured plasmonic sensor for SERS spectroscopy. The p-jet approach allowed us to have an assembly of nanoparticles with suitable geometry and size, which resulted in a sensing surface with intense SERS activity and a rather homogeneous response. Raman imaging measurements highlighted strong Enhancement Factors across the sensing area, exceeding those of the pristine colloidal solution by almost two orders of magnitude. The intense plasmonic effect was further demonstrated by the spectroscopic recognition of a metal-catalyzed dimerization process triggered to completeness at the metal surface. The results presented herein demonstrate the usefulness of the proposed SERS sensor for hypersensitive molecular analysis.

Graphene family materials (GFMs) have large perspectives for drug-delivery applications, but their internalization in live cells is under investigation in a wide variety of studies in order to assess the best conditions for efficient cellular uptake. Here we show that mild oxidation of graphene nanoplatelets produces nanographene oxide (nGO) particles, which are massively internalized into the cell cytoplasm. This remarkable uptake of nGO in NIH-3T3 cells has never been observed before. We performed vitality tests for demonstrating the biocompatibility of the material and analyzed the internalization mechanism under different oxidation degrees and concentrations. Moreover, we evaluated quantitatively, for the first time, the cell volume variation after nGO internalization in live cells through a label-free digital holographic imaging technique and in quasi-real-time modality, thus avoiding the time-consuming and detrimental procedures usually employed by electron-based microscopy. The results demonstrate that nGO formulations with a tailored balance between the exposed surface and content of functional groups are very promising in drug-delivery applications.

A novel method for sensing low abundant lactose in small sample volumes is proposed. It is based on a pyroelectrodynamic jet (p-jet) system able to concentrate the lactose molecules onto a solid amine support for easy and rapid detection through a fluorescence measurement. The p-jet produces droplets with sub-picoliter volumes accumulated onto a microscale area of the solid support in order to reduce the diffusion limits typically occurring in standard well-based assays. A highly reproducible linear response for lactose was obtained between 2 pM/?L and 10 pM/?L. The great advantage of the technique is the ability to concentrate the molecules directly onto the solid support ready for the readout measurement by a standard fluorescence scanner. No time-consuming and expensive sample treatments are needed. The proposed method is rapid, suitable for repeated use providing a built-in quality assurance.

The unique deformability and the compliance ability of thin sheets on soft substrates attract much interest for studying the phenomena related to elastic instabilities as well as for sensing very weak forces such as those generated by live cells in vitro. However, the techniques used currently for producing such platforms are affected by a high degree of complexity and poor repeatability. Moreover, their deformability is usually used as a passive response to the action of an external force. Herein we propose a novel concept for a reliable and dynamic skin-over-liquid system made of a periodic array of highly compliant microbumps actuated through electrode-free electrohydrodynamic (EHD) pressure. We demonstrate that these structures are highly repeatable and capable of swelling and deflating easily under a simple thermal stimulation driven by the pyroelectric effect, thus providing a challenging platform that can be actively controlled at the microscale. Furthermore, we show the proof of principle by swelling these microbumps for mechanically stimulating live cells in vitro, thus opening the route to more reliable and easy to accomplish assays in the field of mechanobiology.

Bacteria are often associated with the insurgence of diseases and many efforts have been made to develop methods for accurate identification of bacteria in food for industry and new generation smart farms. On the other hand, there is a wide category of "good" bacteria that are used in food and pharmaceutic industry. In particular, probiotics are microbial species that have been demonstrated to confer benefits to health, acting against pathologies such as obesity, diabetes, etc. Probiotics have to maintain their viability during their transit through the gastro-intestinal apparatus in order to act to enhance the immune system. The use of alginate microcapsules is one of the most common methods of preservation, applicable to several biological matrices, including probiotics. Here we use bio-speckle decorrelation as a tool for the rapid assessment of microencapsulation effectiveness. Although speckles are often thought as a source of noise, these can be fruitfully used to increase the sensitivity of coherent imaging sensors. Thus, it is possible to characterize bacteria motion and to use it as a contrast agent for applications in food science and industry. Through bio-speckle decorrelation, we detect the presence of bacteria in food without any chemical analysis. Moreover, we quantify the shelf-time of alginate-encapsulated Lactobacillus rhamnosus and Lactobacillus plantarum probiotic bacteria and their survival rate under simulated gastro-intestinal conditions.

Probiotics are microbial species that have been demonstrated to confer benefits to health. In recent years, the use of probiotics in food and health has increased enormously. A sufficient concentration of probiotics in the intestine acts against pathologies such as obesity, diabetes, etc. However, if probiotics are not able to maintain their viability during their transit through the gastro-intestinal apparatus, they cannot act to enhance the immune system. Hence, protection and preservation of probiotics are essential to both food industry and in pharmaceutics. Microencapsulation is one of the most common methods of preservation, applicable to several biological matrices, including probiotics. Whenever food products or pharmaceutical formulations contain microencapsulated probiotics, it is important to quantify the effectiveness of micro-encapsulation as a microbial protection system over the time, e.g. during the shelf life of a functional product containing encapsulated probiotics, conserved in the supermarket, and during gastro-intestinal transit. Here we use bio-speckle decorrelation as a tool for the rapid assessment of microencapsulation effectiveness. Although speckles are often thought as a noise to get rid of, they represent a precious source of information, increasing the sensitivity of image sensors based on coherent illumination. Such information is exploitable to characterize bacterial dynamics in a fast and simple way suitable for applications in food science and industry. Through bio-speckle decorrelation, we quantify the shelf-time of alginate-encapsulated Lactobacillus rhamnosus and Lactobacillus plantarum probiotic bacteria and their survival rate under simulated gastro-intestinal conditions.

Digital holographic microscopy (DHM) has become a technique utilized widely for sample inspection, having many applications in different fields of science and technology. The capability for recovering the complex amplitude distribution scattered by the sample permits numerical refocus after acquisition and quantitative phase imaging. These are two of the features that make DHM a very versatile microscopy technique. The standard DHM system is based on a Mach-Zehnder interferometer that can be configured for operating in transmission or reflection modes, working in either the in-line or off-axis architecture. With the benefit of such special characteristics, DHM is used in basic research as much in the industry. Here we review some of the recent advancements for the label-free inspection of biological samples and the study of thin films.

Unique feature of DH for implementing numerical scanning of the reconstruction distance is used to characterize near-field propagation properties of phase structures imprinted into photorefractive Lithium Niobate crystals by biolenses as Red Blood Cells.

All-optical activation of electric fields in smart materials is a challenging issue for avoiding complex and multiple steps in material processing. Photo-activation of electrodes can be realized in photorefractive (PR) crystals where the interaction with light of suitable wavelength and power generates charge displacements and stable space electric fields. In past years many efforts have been spent for studying PR fields in ferroelectric material such as Lithium Niobate (LN) [1,2] and many applications have been demonstrated for dielectrophoretic (DEP) trapping of microparticles [3,4] and for sensing in microfluidic environment [6,7]. Recently it has been investigated the interaction of such fields with biological samples thus proving its biocompatibility for tissue growth [8] of for biosensing applications [9].

Red blood cells on the surface of a lithium niobate crystal can be used as optical lenses for direct writing of laser-induced refractive index changes. The writing process by such a photomask made of biological lenses is due to the photorefractive effect. Wavefront analysis by a digital holographic microscope is performed for deep and accurate evaluation of local refractive index changes. Different focusing properties can be imprinted on the crystal depending on which type of RBC is employed, discocytes or spherical-like RBCs. The possibility to fix into a solid material the optical fingerprint of the RBCs will have an impact on both diagnostics and cell\material interfacing.

Localized electric fields have become, in recent years, a source of inspiration to researchers and laboratories thanks to a huge amount of applications derived from it, including positioning of microparticles as building blocks for electrical, optical, and magnetic devices. The possibility of producing polymeric materials with surface charge thus opens new perspectives for applications where process simplicity and cost-effectiveness of flexible electronics are of fundamental importance. In particular, the influence of surface charges is widely studied and is a critical issue especially when new materials and functional technologies are introduced. Here, we report a voltage-free pyro-electrification (PE) process able to induce a permanent dipole orientation into polymer sheets under both mono- and bipolar distribution. The technique makes use of the pyroelectric effect for generating electric potentials on the order of kilovolts by an easy-to-accomplish thermal treatment of ferroelectric lithium niobate (LN) crystals. The PE allows us to avoid the expensive and time-consuming fabrication of high-power electrical circuits, as occurs in traditional generator-based techniques. Since the technique is fully compatible with spin-coating-based procedures, the pyro-electrified polymer sheets are easily peeled off the surface of the LN crystal after PE completion, thus providing highly stable and freestanding charged sheets. We show the reliability of the technique for different polymers and for different applications ranging from live cell patterning to biofilm formation tests for bacteria linked to food-processing environments.

Graphene family materials (GFM) have large perspectives for drug delivery applications but their internalization in live cells is under investigation in a wide variety of studies in order to assess the best conditions for efficient cellular uptake. Here we show that mild oxidation of graphene nanoplatelets produces nano-graphene oxide (nGO) particles which are massively internalized into the cell cytoplasm. This remarkable uptake of nGO in NIH-3T3 cells has never been observed before. We performed vitality tests for demonstrating the biocompatibility of the material and analyzed the internalization mechanism under different oxidation degrees and concentrations. Moreover, we evaluated quantitatively, for the first time, the cell volume variation after nGO internalization in live cells through a label-free digital holographic imaging technique and in quasi real-time modality, thus avoiding the time consuming and detrimental procedures usually employed by electron-based microscopy. The results demonstrate that nGO formulations with a tailored balance between exposed surface and content of functional groups are very promising in drug delivery applications.