Palmitoylethanolamide sub-micronization using fast precipitation followed by supercritical fluids extraction

Sub-micronization of palmitoylethanolamide (PEA) was successfully performed using fast precipitation coupled with supercritical fluid extraction. Different solvents were tested: acetone, ethyl acetate, isopropanol, dimethyl sulfoxide and ethanol; water was used as the antisolvent. PEA precipitated in all cases as crystals of hexagonal morphology. The best result in terms of control of dimension of the crystals was obtained using ethanol as solvent. Moreover, varying the concentration of PEA in the solution from 5 to 9\uc2 mg/mL, it was observed an increase of crystal dimensions. The effect of other process parameters, such as the solvent/antisolvent ratio and the concentration of surfactant in the antisolvent phase, was investigated to better control the crystallization process. Micronized crystals with controlled and regular dimensions (about 1\uc2 \uce\ubcm) and nanometric thickness (about 100\uc2 nm) were obtained at the optimized process conditions. A mass reduction of PEA particles of about ten times was obtained with respect to jet milling micronized particles. The supercritical extraction process, performed at 120\uc2 bar, 44\uc2 \uc2\ub0C and at a liquid to gas ratio of 0.05, allowed the selective extraction of ethanol from the water suspensions with a final solvent residue of 88\uc2 ppm; i.e. well below the pharmacopeia limit. Particles characterization was also performed using X-ray diffraction, differential scanning calorimetry and Fourier transform infrared spectroscopy. PEA fast precipitated particles were characterized by a reduced degree of crystallinity with respect to unprocessed PEA

Detecting collagen molecules at picogram level through electric field-induced accumulation

: 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

A skin-over-liquid platform with compliant microbumps actuated by pyro-EHD pressure

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

Highly sensitive detection of low abundant molecules by pyro-electrohydro-dynamic jetting

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. 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