Advances in the Physico-Chemical, Antimicrobial and Angiogenic Properties of Graphene-Oxide/Cellulose Nanocomposites for Wound Healing.

Graphene oxide (GO) and its reduced form (rGO) have recently attracted a fascinating interest due to their physico-chemical properties, which have opened up new and interesting opportunities in a wide range of biomedical applications, such as wound healing. It is worth noting that GO and rGO may offer a convenient access to its ready dispersion within various polymeric matrices (such as cellulose and its derivative forms), owing to their large surface area, based on a carbon skeleton with many functional groups (i.e., hydroxyl, carboxyl, epoxy bridge, and carbonyl moieties). This results in new synergic properties due to the presence of both components (GO or rGO and polymers), acting at different length-scales. Furthermore, they have shown efficient antimicrobial and angiogenic properties, mostly related to the intracellular formation of reactive oxygen species (ROS), which are advantageous in wound care management. For this reason, GO or rGO integration in cellulose-based matrixes have allowed for designing highly advanced multifunctional hybrid nanocomposites with tailored properties. The current review aims to discuss a potential relationship between structural and physico-chemical properties (i.e., size, edge density, surface chemistry, hydrophilicity) of the nanocomposites with antimicrobials and angiogenic mechanisms that synergically influence the wound healing phenomenon, by paying particular attention to recent findings of GO or rGO/cellulose nanocomposites. Accordingly, after providing a general overview of cellulose and its derivatives, the production methods used for GO and rGO synthesis, the mechanisms that guide antimicrobial and angiogenic processes of tissue repair, as well as the most recent and remarkable outcomes on GO/cellulose scaffolds in wound healing applications, will be presented.

Special Issue: Advanced Nanocomposite Materials Based on Graphene Oxide/Reduced Graphene Oxide: Potential Applications and Perspectives.

In recent years, graphene oxide (GO) and reduced graphene oxide (r-GO) have received much attention as precursors of graphene-like 2D nanomaterials [...].

A Brief Review: The Use of L-Ascorbic Acid as a Green Reducing Agent of Graphene Oxide.

The reduced form of graphene oxide (r-GO) represents a versatile precursor to obtain graphene derivatives. Graphene oxide (GO) consists of a layered material based on a carbon skeleton functionalized by different oxygen-containing groups, while r-GO is obtained by the almost complete removal of these oxygen-containing functional groups. The r-GO has mechanical, electrical, and optical properties quite similar to graphene, thus, it proves to be a convenient 2D material useful for many technological applications. Nowadays, the most important aspects to consider in producing r-GO are: (i) the possibility of obtaining the highest reduction grade; (ii) the possibility of improving the dispersion stability of the resulting graphene using surfactants; (iii) the use of environmentally friendly and inexpensive reducing agents. Consequently, the availability of effective soft-chemistry approaches based on a green reducing agent for converting GO to r-GO are strongly needed. Among the green reductants, the most suitable is L-ascorbic acid (L-aa). Different studies have revealed that L-aa can achieve C/O ratio and conductivity values comparable to those obtained by hydrazine, a typical reducing agent. These aspects could promote an effective application strategy, and for this reason, this review summarizes and analyzes, in some detail, the up-to date literature on the reduction of GO by L-aa. The results are organized according to the two most important approaches, which are the reduction in liquid-phase, and the reduction in gel-phase. Reaction mechanisms and different experimental parameters affecting the processes were also compared.

Hypothalamic NPY-Y1R Interacts with Gonadal Hormones in Protecting Female Mice against Obesity and Neuroinflammation.

We previously demonstrated that Npy1rrfb mice, which carry the conditional inactivation of the Npy1r gene in forebrain principal neurons, display a sexually dimorphic phenotype, with male mice showing metabolic, hormonal and behavioral effects and females being only marginally affected. Moreover, exposure of Npy1rrfb male mice to a high-fat diet (HFD) increased body weight growth, adipose tissue, blood glucose levels and caloric intake compared to Npy1r2lox male controls. We used conditional knockout Npy1rrfb and Npy1r2lox control mice to examine whether forebrain disruption of the Npy1r gene affects susceptibility to obesity and associated disorders of cycling and ovariectomized (ovx) female mice in a standard diet (SD) regimen or exposed to an HFD for 3 months. The conditional deletion of the Npy1r gene increased body weight and subcutaneous white adipose tissue weight in both SD- and HFD-fed ovx females but not in cycling females. Moreover, compared with ovx control females on the same diet regimen, Npy1rrfb females displayed increased microglia number and activation, increased expression of Neuropeptide Y (NPY)-immunoreactivity (IR) and decreased expression of proopiomelanocortin-IR in the hypothalamic arcuate nucleus (ARC). These results suggest that in the ARC NPY-Y1R reduces the susceptibility to obesity of female mice with low levels of gonadal hormones and that this effect may be mediated via NPY-Y1R ability to protect the brain against neuroinflammation.

Knock out of sHSP genes determines some modifications in the probiotic attitude of Lactiplantibacillus plantarum.

OBJECTIVE: We investigated whether the knock out of small heat shock protein (sHSP) genes (hsp1, hsp2 and hsp3) impact on probiotic features of Lactiplantibacillus plantarum WCFS1, aiming to find specific microbial effectors involved in microbe-host interplay. RESULTS: The probiotic properties of L. plantarum WCFS1 wild type, hsp1, hsp2 and hsp3 mutant clones were evaluated and compared through in vitro trials. Oro-gastro-intestinal assays pointed to significantly lower survival for hsp1 and hsp2 mutants under stomach-like conditions, and for hsp3 mutant under intestinal stress. Adhesion to human enterocyte-like cells was similar for all clones, though the hsp2 mutant exhibited higher adhesiveness. L. plantarum cells attenuated the transcriptional induction of pro-inflammatory cytokines on lipopolysaccharide-treated human macrophages, with some exception for the hsp1 mutant. Intriguingly, this clone also induced a higher IL10/IL12 ratio, which is assumed to indicate the anti-inflammatory potential of probiotics. CONCLUSIONS: sHSP genes deletion determined some differences in gut stress resistance, cellular adhesion and immuno-modulation, also implying effects on in vivo interaction with the host. HSP1 might contribute to immunomodulatory mechanisms, though additional experiments are necessary to test this feature.

Sex differences in behavioral and metabolic effects of gene inactivation: The neuropeptide Y and Y receptors in the brain.

Brain and gonadal hormones interplay controls metabolic and behavioral functions in a sex-related manner. However, most translational neuroscience research related to animal models of endocrine and psychiatric disorders are often carried out in male animals only. The Neuropeptide Y (NPY) system shows sex-dependent differences and is sensitive to gonadal steroids. Based on published data from our and other laboratories, in this review we will discuss the sex related differences of NPY action on energy balance, bone homeostasis and behavior in rodents with the genetic manipulation of genes encoding NPY and its Y1, Y2 and Y5 cognate receptors. Comparative analyses of the phenotype of transgenic and knockout NPY and Y receptor rodents unravels sex dependent differences in the functions of this neurotransmission system, potentially helping to develop therapeutics for a variety of sex-related disorders including metabolic syndrome, osteoporosis and ethanol addiction.

Conditional inactivation of Npy1r gene in mice induces sex-related differences of metabolic and behavioral functions.

Sex hormone-driven differences in gene expression have been identified in experimental animals, highlighting brain neuronal populations implicated in dimorphism of metabolic and behavioral functions. Neuropeptide Y-Y1 receptor (NPY-Y1R) system is sexually dimorphic and sensitive to gonadal steroids. In the present study we compared the phenotype of male and female conditional knockout mice (Npy1rrfb mice), carrying the inactivation of Npy1r gene in excitatory neurons of the brain limbic system. Compared to their male control (Npy1r2lox) littermates, male Npy1rrfb mice exhibited hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis that is associated with anxiety and executive dysfunction, reduced body weight growth, after-fasting refeeding, white adipose tissue (WAT) mass and plasma leptin levels. Conversely, female Npy1rrfb mice displayed an anxious-like behavior but no differences in HPA axis activity, executive function and body weight, compared to control females. Moreover, conditional inactivation of Npy1r gene induced an increase of subcutaneous and gonadal WAT weight and plasma leptin levels and a compensatory decrease of Agouti-related protein immunoreactivity in the hypothalamic arcuate (ARC) nucleus in females, compared to their respective control littermates. Interestingly, Npy1r mRNA expression was reduced in the ARC and in the paraventricular hypothalamic nuclei of female, but not male mice. These results demonstrated that female mice are resilient to hormonal and metabolic effects of limbic Npy1r gene inactivation, suggesting the existence of an estrogen-dependent relay necessary to ensure the maintenance of the homeostasis, that can be mediated by hypothalamic Y1R.

How probiotics face food stress: They get by with a little help.

The dietary consumption of probiotics in the form of pharmaceuticals or functional food can improve human health and contribute to disease prevention. However, the biological activity and health potential of food-delivered probiotics can be severely compromised by the stress conditions encountered by the microorganisms throughout the manufacture process, from probiotic preparation to their inclusion into food, subsequent storage and ingestion. Here, we give an account of the stress factors that can have major negative impacts on probiotic viability and functionality, with a focus on food-related environmental adverse conditions. We also describe some of the mechanisms elicited by the microbial cells to counteract these stresses and summarize a few relevant approaches proposed in literature to develop more robust and competitive probiotics by enhancing their stress tolerance, with the aim to improve the efficacy and health value of probiotic functional food.

Thermoresistive Properties of Graphite Platelet Films Supported by Different Substrates.

Large-area graphitic films, produced by an advantageous technique based on spraying a graphite lacquer on glass and low-density polyethylene (LDPE) substrates were studied for their thermoresistive applications. The spray technique uniformly covered the surface of the substrate by graphite platelet (GP) unities, which have a tendency to align parallel to the interfacial plane. Transmission electron microscopy analysis showed that the deposited films were composed of overlapped graphite platelets of different thickness, ranging from a few tens to hundreds of graphene layers, and Raman measurements provided evidence for a good graphitic quality of the material. The GP films deposited on glass and LDPE substrates exhibited different thermoresistive properties during cooling-heating cycles in the -40 to +40 °C range. Indeed, negative values of the temperature coefficient of resistance, ranging from -4 × 10-4 to -7 × 10-4 °C-1 have been observed on glass substrates, while positive values varying between 4 × 10-3 and 8 × 10-3 °C-1 were measured when the films were supported by LDPE. These behaviors were attributed to the different thermal expansion coefficients of the substrates. The appreciable thermoresistive properties of the graphite platelet films on LDPE could be useful for plastic electronic applications.

The Phenotypic Analysis of Lactobacillus plantarum shsp Mutants Reveals a Potential Role for hsp1 in Cryotolerance.

Small heat shock proteins (sHSPs) are ubiquitous, low molecular weight (MW) proteins that share a conserved alpha-crystallin domain. sHSPs oligomers exhibit chaperon-like activities by interacting with unfolded substrates, thereby preventing their aggregation and precipitation. Unlike most lactobacilli, which have single shsp genes, three different sHSP-encoding genes, i.e., hsp1, hsp2, and hsp3, were previously identified in the probiotic Lactobacillus plantarum WCFS1. Early studies, including the characterization of the knock out (KO) mutant for hsp2, indicated a different organization and transcriptional regulation of these genes and suggested that the three L. plantarum sHSPs might accomplish different tasks in stress response. To unravel the role of sHSPs, KO mutants of hsp1 and hsp3 were generated using a Cre-lox based system. Mutation of either genes resulted in impaired growth capacity under normal conditions, heat-stress and stresses typically found during host interactions and food technological process. However, survival to heat shock and the level of thermal stabilization of cytoplasmic proteins were similar between mutants and parental strain. Transcriptional analysis revealed that in the mutant genetic backgrounds there is an upregulated basal expression of the un-mutated mate hsps and other stress-related genes, which may compensate for the loss of HSP function, hence possibly accounting for the lack of a remarkable susceptibility to heat challenge. HSP3 seemed relevant for the induction of thermotolerance, while HSP1 was required for improved cryotolerance. Cell surface properties and plasma membrane fluidity were investigated to ascertain the possible membrane association of sHSP. Intriguingly, the loss of hsp1 was associated to a lower level of maximal membrane fluidity upon heat stress. A role for HSP1 in controlling and improving membrane fluidity is suggested which may pertains its cryoprotective function.

Conditional inactivation of Npy1r gene in mice induces behavioural inflexibility and orbitofrontal cortex hyperactivity that are reversed by escitalopram.

Cognitive flexibility is the ability to rapidly adapt established patterns of behaviour in the face of changing circumstance and depends critically on the orbitofrontal cortex (OFC). Impaired flexibility also results from altered serotonin transmission in the OFC. The Y1 (Y1R) and Y5 (Y5R) receptors for neuropeptide Y (NPY) colocalize in several brain regions and have overlapping functions in regulating cognition and emotional behaviour. The targeted disruption of gene encoding Y1R (Npy1r gene) in Y5R containing neurons (Npy1rY5R-/- mice) increases anxiety-like behaviour and spatial reference memory. Here we used the same conditional system to analyse whether the coordinated expression of the Y1R and Y5R might be required for behavioural flexibility in reversal learning tasks, OFC serotoninergic tone and OFC neural activity, as detected by immunohistochemical quantification of the immediate-early gene, c-Fos. In addition, we investigated whether the acute treatment of Npy1rY5R-/- mice with the selective serotonin reuptake inhibitor escitalopram affected behavioural flexibility and OFC c-Fos expression. Npy1rY5R-/- male mice exhibit an impairment in performing the reversal task of the Morris water maze and the water T-maze but normal spatial learning, working memory and sociability, compared to their control siblings. Furthermore, Npy1rY5R-/- male mice display decreased 5-hydroxytriptamine (5-HT) positive fibres and increased baseline neural activity in OFC. Importantly, escitalopram normalizes OFC neural activity and restores behavioural flexibility of Npy1rY5R-/- male mice. These findings suggest that the inactivation of Y1R in Y5R containing neurons increases pyramidal neuron activity and dysregulates serotoninergic tone in OFC, whereby contributing to reversal learning impairment.

Patient-reported outcome measures for young people with developmental disabilities: incorporation of design features to reduce cognitive demands.

Use of patient-reported outcome measures (PROMs) may increase the involvement of young people with developmental disabilities in their healthcare decisions and healthcare-related research. Young people with developmental disabilities may have difficulty completing PROMs because of extraneous assessment demands that require additional cognitive processes. However, PROM design features may mitigate the impact of these demands. We identified and evaluated six pediatric PROMs of self-care and domestic life tasks for the incorporation of suggested design features that can reduce cognitive demands. PROMs incorporated an average of 6 out of 11 content, 7 out of 14 layout, and 2 out of 9 administration features. This critical review identified two primary gaps in PROM design: (1) examples and visuals were not optimized to reduce cognitive demands; and (2) administration features that support young people's motivation and self-efficacy and reduce frustration were underutilized. Because assessment demands impact the validity of PROMs, clinicians should prospectively consider the impact of these demands when selecting PROMs and interpreting scores. WHAT THIS PAPER ADDS: Patient-reported outcome measure (PROM) design features can reduce assessment demands related to cognitive processes. Pediatric PROMs underutilize design features that decrease cognitive demands of self-reporting.

Lactobacillus plantarum with Broad Antifungal Activity as a Protective Starter Culture for Bread Production.

Bread is a staple food consumed worldwide on a daily basis. Fungal contamination of bread is a critical concern for producers since it is related to important economic losses and safety hazards due to the negative impact of sensorial quality and to the potential occurrence of mycotoxins. In this work, Lactobacillus plantarum UFG 121, a strain with characterized broad antifungal activity, was analyzed as a potential protective culture for bread production. Six different molds belonging to Aspergillus spp., Penicillium spp., and Fusarium culmorum were used to artificially contaminate bread produced with two experimental modes: (i) inoculation of the dough with a commercial Saccharomyces cerevisiae strain (control) and (ii) co-inoculation of the dough with the commercial S. cerevisiae strain and with L. plantarum UFG 121. L. plantarum strain completely inhibited the growth of F. culmorum after one week of storage. The lactic acid bacterium modulated the mold growth in samples contaminated with Aspergillus flavus, Penicillium chrysogenum, and Penicillium expansum, while no antagonistic effect was found against Aspergillus niger and Penicillium roqueforti. These results indicate the potential of L. plantarum UFG 121 as a biocontrol agent in bread production and suggest a species- or strain-depending sensitivity of the molds to the same microbial-based control strategy.

Graphene-polymer coating for the realization of strain sensors.

In this work we present a novel route to produce a graphene-based film on a polymer substrate. A transparent graphite colloidal suspension was applied to a slat of poly(methyl methacrylate) (PMMA). The good adhesion to the PMMA surface, combined with the shear stress, allows a uniform and continuous spreading of the graphite nanocrystals, resulting in a very uniform graphene multilayer coating on the substrate surface. The fabrication process is simple and yields thin coatings characterized by high optical transparency and large electrical piezoresitivity. Such properties envisage potential applications of this polymer-supported coating for use in strain sensing. The electrical and mechanical properties of these PMMA/graphene coatings were characterized by bending tests. The electrical transport was investigated as a function of the applied stress. The structural and strain properties of the polymer composite material were studied under stress by infrared thermography and micro-Raman spectroscopy.

Sex-dependent regulation of hypothalamic neuropeptide Y-Y1 receptor gene expression in leptin treated obese (ob/ob) or lean mice.

Pharmacological and genetic studies have shown that the Y1 receptor (Y1R) for Neuropeptide Y (NPY) plays a crucial role in the control of feeding behavior under metabolic conditions of low leptin levels or leptin deficiency. In this study, we investigated the effect of leptin deficiency and leptin replacement on Y1R gene expression in the hypothalamus of lean and obese Y1R/LacZ transgenic mice (TgY1R/LacZ) carrying the murine Y1R promoter linked to the LacZ gene that induces the expression of ß-galactosidase. Two daily intraperitoneal injections with leptin (1µg/g of body weight for one week) of male and female lean (TgY1R/LacZ+/+) and obese (TgY1R/LacZob/ob) mice induced a significant decrease of body weight in both sexes and genotypes. In males, leptin administration decreased ß-galactosidase activity in the PVN and DMH of lean mice, and increased transgene expression in the same hypothalamic nuclei of obese mice. Sex-related differences were also observed in both genotypes, since leptin treatment failed to affect transgene expression in hypothalamus of lean and obese female mice. These results provide further evidence for a sexual dimorphism of the hypothalamic NPY-Y1R-mediated pathway in response to changes in leptin circulating levels.

Imidazole-stabilized gold nanoparticles induce neuronal apoptosis: an in vitro and in vivo study.

Gold nanoparticles are increasingly being employed in innovative biological applications thanks to their advantages of material- and size-dependent physics and chemical interactions with the cellular systems. On the other hand, growing concern has emerged on the toxicity which would render gold-based nanoparticles harmful to cell cultures, animals, and humans. Emerging attention is focused on the interaction of gold nanoparticles with nervous system, especially regarding the ability to overcome the blood-brain barrier (BBB) which represents the major impediment to the delivery of therapeutics into the brain. We synthesized highly stable 2-mercapto-1-methylimidazole-stabilized gold-nanoparticles (AuNPs)-mmi to investigate their entry, accumulation, and toxicity in vitro (SH-SY5Y human neuroblastoma cells) and in vivo (brain of C57BL/6 mice) through optical and electron microscopy. After incubation in the cell culture medium at the lowest dose of 0.1 mg/mL the (AuNPs)-mmi nanoparticles were found compacted and recruited into endosome/lysosomes (1 h) before their fusion (2 h) and the onset of neuronal death by apoptosis (4 h) as proved by terminal-transferase-mediated dUTP nick end labeling assay and caspase-3 immunoreactivity. The ability of (AuNPs)-mmi to cross the BBB was assessed by injection in the caudal vein of C57BL/6 mice. Among different brain regions, the nanoparticles were found in the CaudatoPutamen area, mainly in the striatal neurons 4 h after injection. These neurons showed the typical hallmarks of apoptosis. Our findings provide, for the first time, the dynamic of 2-mercapto-1-methylimidazole nanogold uptake. The molecular mechanism which underlies the nanogold-driven apoptotic event is analyzed and discussed in order to take into account when designing nanomaterials to interface with biological structures.

Estrogen replacement therapy regulation of energy metabolism in female mouse hypothalamus.

Estrogens play an important role in the regulation of energy homeostasis in female mammals and a reduced ovarian function, due to natural aging or surgery, is associated with body weight increase and fat redistribution. This disruption of energy homeostasis may constitute a trigger for several pathologies known to be associated with climacterium; however, so far, limited attention has been devoted to the ability of estrogen replacement therapies (ERT) to reinstate the balanced energy metabolism characteristic of cycling female mammals. The purpose of the present study was to compare the efficacy of selected ERTs in reversing the ovariectomy-induced gain in body weight. To this aim female ERE-Luc mice were ovariectomized and, after 3 weeks, treated per os for 21 days with: conjugated estrogens, two selective estrogen receptor modulators (bazedoxifene and raloxifene), and the combination of bazedoxifene plus conjugated estrogens (tissue-selective estrogen complex, TSEC). The study shows that the therapy based on TSEC was the most efficacious in reducing the body weight accrued by ovariectomy (OVX). In addition, by means of in vivo imaging, the TSEC treatment was shown to increase estrogen receptor (ER) transcriptional activity selectively in the arcuate nucleus, which is a key area for the control of energy homeostasis. Finally, quantitative analysis of the mRNAs encoding orexigenic and anorexigenic peptides indicated that following ERT with TSEC there was a significant change in Agrp, NPY, and Kiss-1 mRNA accumulation in the whole hypothalamus. Considering that prior studies showed that ERT with TSEC was able to mimic the rhythm of ER oscillatory activity during the reproductive cycle and that such fluctuations were relevant for energy metabolism, the present observations further point to the ER tetradian oscillation as an important component of the ER signaling necessary for the full hormone action and therefore for an efficacious ERT.

Conditional inactivation of neuropeptide Y Y1 receptors unravels the role of Y1 and Y5 receptors coexpressing neurons in anxiety.

BACKGROUND: The Y1 receptor (Y1R) and Y5 receptor (Y5R) for neuropeptide Y share similar actions in the regulation of anxiety. Previously demonstrated that conditional removal of the Y1R during postnatal development in the forebrain excitatory neurons leads to higher anxiety, increased hypothalamus-pituitary-adrenocortical axis activity, and decreased body growth rate in male mice raised by foster mothers that exhibit high levels of maternal care. In the present study, we used the same conditional system to analyze the specific contribution to emotional behavior and stress response of the Y1R coexpressed with the Y5R. METHODS: Using the Cre-loxP recombination system, we investigated anxious behavior, spatial memory, and metabolic functions of conditional knockout mice in which the inactivation of the Npy1r gene was induced in the Y5Rs expressing neurons of juvenile mice (Npy1r(Y5R-/-) ). RESULTS: Npy1r(Y5R-/-) mice show increased anxiety-related behavior but no changes in hypothalamus-pituitary-adrenocortical axis activity or in body weight growth, independently of gender and mouse strain used as foster mothers. Also, Npy1r(Y5R-/-) mice of both genders display increased spatial reference memory in the Morris water maze test. CONCLUSIONS: The results suggest that neuropeptide Y Y1R differentially expressed in the limbic system regulates anxiety and stress responses via distinct neurochemical circuits. In addition, we provide the first experimental genetic evidence that the Y1Rs coexpressed with the Y5R are involved in retention of spatial memory in male and female mice.

A simple mechanical technique to obtain carbon nanoscrolls from graphite nanoplatelets.

A simple approach for the bulk production of carbon nanoscrolls (CNSs) is described. This method is based on the application of shear-friction forces to convert graphite nanoplatelets into carbon nanoscrolls using a bi-axially oriented polypropylene (BOPP) surface. The combined action of shear and friction forces causes the exfoliation of graphite nanoplatelets and the simultaneous roll-up of graphite layers. Evidence of the CNS formation is given by optical microscopy, scanning electron microscopy, and transmission electron microscopy. These investigations reveal that the CNSs have a long tube-like and fusiform structure with a hollow core surrounded by few layers of graphene. Micro-Raman spectroscopy shows that the produced structures are not defect free, and optical spectroscopy reveals distinctive features due to the presence of two weak absorption bands at 224 and 324 nm.

A minimally invasive microchip for transdermal injection/sampling applications.

The design, fabrication, and characterization of a minimally invasive silicon microchip for transdermal injection/sampling applications are reported and discussed. The microchip exploits an array of silicon-dioxide hollow microneedles with density of one million needles cm(-2) and lateral size of a few micrometers, protruding from the front-side chip surface for one hundred micrometers, to inject/draw fluids into/from the skin. The microneedles are in connection with independent reservoirs grooved on the back-side of the chip. Insertion experiments of the microchip in skin-like polymers (agarose hydrogels with concentrations of 2% and 4% wt) demonstrate that the microneedles successfully withstand penetration without breaking, despite their high density and small size, according to theoretical predictions. Operation of the microchip with different liquids of biomedical interest (deionized water, NaCl solution, and d-glucose solution) at different differential pressures, in the range 10-100 kPa, highlights that the flow-rate through the microneedles is linearly dependent on the pressure-drop, despite the small section area (about 13 µm(2)) of the microneedle bore, and can be finely controlled from a few ml min(-1) up to tens of ml min(-1). Evaporation (at room temperature) and acceleration (up to 80 g) losses through the microneedles are also investigated to quantify the ability of the chip in storing liquids (drug to be delivered or collected fluid) in the reservoir, and result to be of the order of 70 nl min(-1) and 1300 nl min(-1), respectively, at atmospheric pressure and room temperature.