Bioresorbable Materials on the Rise: From Electronic Components and Physical Sensors to In Vivo Monitoring Systems

Over the last decade, scientists have dreamed about the development of a bioresorbable technology that exploits a new class of electrical, optical, and sensing components able to operate in physiological conditions for a prescribed time and then disappear, being made of materials that fully dissolve in vivo with biologically benign byproducts upon external stimulation. The final goal is to engineer these components into transient implantable systems that directly interact with organs, tissues, and biofluids in real-time, retrieve clinical parameters, and provide therapeutic actions tailored to the disease and patient clinical evolution, and then biodegrade without the need for device-retrieving surgery that may cause tissue lesion or infection. Here, the major results achieved in bioresorbable technology are critically reviewed, with a bottom-up approach that starts from a rational analysis of dissolution chemistry and kinetics, and biocompatibility of bioresorbable materials, then moves to in vivo performance and stability of electrical and optical bioresorbable components, and eventually focuses on the integration of such components into bioresorbable systems for clinically relevant applications. Finally, the technology readiness levels (TRLs) achieved for the different bioresorbable devices and systems are assessed, hence the open challenges are analyzed and future directions for advancing the technology are envisaged

Antimicrobial peptide human β-defensin-2 improves in vitro cellular viability and reduces pro-inflammatory effects induced by enteroinvasive Escherichia coli in Caco-2 cells by inhibiting invasion and virulence factors’ expression

Escherichia coli is one of the commensal species most represented in the intestinal microbiota. However, there are some strains that can acquire new virulence factors that enable them to adapt to new intestinal niches. These include enteroinvasive E. coli (EIEC) that is responsible for the bacillary dysentery that causes severe diarrheal symptoms in both children and adults. Due to the increasing onset of antibiotic resistance phenomena, scientific research is focused on the study of other therapeutic approaches for the treatment of bacterial infections. A promising alternative could be represented by antimicrobial peptides (AMPs), that have received widespread attention due to their broad antimicrobial spectrum and low incidence of bacterial resistance. AMPs modulate the immune defenses of the host and regulate the composition of microbiota and the renewal of the intestinal epithelium. With the aim to investigate an alternative therapeutic approach, especially in the case of antibiotic resistance, in this work we created a line of intestinal epithelial cells able to express high concentrations of AMP human β-defensin-2 (HBD-2) in order to test its ability to interfere with the pathogenicity mechanisms of EIEC. The results showed that HBD-2 is able to significantly reduce the expression of the proinflammatory cytokines by intestinal epithelial cells, the invasiveness ability of EIEC and the expression of invasion-associated genes

Bacterial contamination of saline nasal irrigations in children: An original research

Microbiologic analysis of nasal saline irrigations (NSIs) used in hospitalized children was performed. Of 253 collected samples, 24.9% were positive, and the number of positive samples significantly increased over time (P < .001). Staphylococcus aureus was the most frequently detected bacterium (28.6%). None of the 118 patients who received NSIs developed a nasosinusal infection. Colonization by cutaneous and environmental germs is frequent and develops early. Hygienic measures should be advocated to reduce contamination

Metabolic parameters and adipokine profile during GH replacement therapy in children with GH deficiency

Objective: GH replacement therapy in children with GH deficiency (GHD) mainly promotes linear growth. Not only have very few studies fully analyzed the metabolic consequences of GH therapy, but also the question as to whether GH may affect adipokine secretion has been insufficiently investigated. Our aim was to study the effects of GH replacement therapy on auxological data, lipid and glycemic profiles, insulin homeostasis (HOMA-IR) and serum adipokines in children. Methods: This was a 1-year prospective study. Thirty-four GHD children (11.6G2.6 years) and thirty healthy matched controls were enrolled. Children affected by GHD were studied both before beginning continuous GH replacement therapy and again at 12 months. Results: At the beginning of the study, total and LDL cholesterol were higher in GHD children than in controls (P!0.001), whereas HDL cholesterol, triglycerides, insulin, HOMA-IR, leptin, and adiponectin were similar. At 12 months of continuous GH replacement therapy in the GHD group, there was a significant increase in both auxological data and IGF-I (P!0.001); total cholesterol (P!0.001), LDL (P!0.001), triglycerides (P!0.005), and leptin (P!0.001) decreased significantly; HDL (P!0.003), insulin (P!0.001), HOMA-IR (P!0.001) increased while adiponectin was unmodified. Furthermore, IGF-ID showed an inverse correlation with leptin D (rZK0.398, PZ0.02). Conclusions: In GHD children, the evaluation of metabolic parameters proves to be a useful tool for the evaluation of auxological parameters during GH replacement therapy. In our study, GH replacement therapy in GHD children improved final height, restored IGF-I levels, reduced leptin levels, and improved the lipid profile, without producing any unfavorable effects on glucose metabolism

CD4(+)IL-13(+) cells in peripheral blood well correlates with the severity of atopic dermatitis in children

In atopic dermatitis (AD) a Th1/Th2 imbalance has been reported, and interleukin (IL)-13 seems to play a pivotal role in the inflammatory network. We tried to assess the correlation between the immunological marker CD4(+)IL-13(+) and the clinical phase of extrinsic AD in children

Short and middle term effects of hypocaloric low carbohydrate diet vs hypocaloric Mediterranean diet on endothelial function in obese subjects

Adequate nutritional treatment is required to address the problem of increasing prevalence of obesity in Western countries. The Mediterranean diet style is now acknowledged to have large scientific evidences in terms of cardiovascular prevention. However, many popular diets are diffusing also as self-prescribed treatments. Among those, the efficacy of low-carbohydrate diets (also known as Atkins’ diet in its most popular variety) has been addressed by some investigations. It is generally concluded that the low-carbohydrate diet is able to induce a greater weight loss, at least in the middle term, and a better serum lipid profile than the conventional diet. In this longitudinal, randomised, open study we compared the effects on endothelial function of a hypocaloric low-carbohydrate diet (according to the Atkins’ diet; AD) versus a similarly hypocaloric Mediterranean diet (MD). Overweight-obese (range of BMI: 27-34.9 Kg/m2; range of age: 30-50 years) otherwise healthy, normal glucose tolerant women were enrolled and randomly assigned to one of the two dietary treatments until reaching the final number of 10 women for each group of treatment. So, twenty-five women were enrolled and five of them (3 in the MD group and 2 in the AD group) were subsequently excluded from the study due to intercurrent diseases (1 subject) or declaration of inadequate compliance (2 subjects) or f voluntary drop out (2 subjects). Measurements were performed before (T0), 5-7 days (T5) and 2 months (T60) after starting the diet treatment. Endothelial function was investigated at each time of the study by measuring the brachial artery flow-mediated dilation (FMD). Serum concentrations of insulin, adiponectin, interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and 8-iso-prostaglandin (8-iso-PG) F2α were also assessed at each time of the study. Urinary ketone bodies were observed at T5 only in AD group. Briefly, body weight was not significantly decreased at T5 in both groups; as expected, a higher body weight reduction was observed at T60 in AD group (change in body weight T60 – T0, mean ± sem, MD -4.9 ± 0.6 Kg vs AD -7.6 ± 0.8 Kg, p= 0.014). The FMD was significantly reduced at T5 in the AD group and increased at T60 until reaching the T0 values (T0: 12.2 ± 2.9; T5: 5.2 ± 0.8; T60: 11.0 ± 1.2 %; p< 0.05 T5 vs T0 and T60). On the contrary, the FMD increased significantly at T5 in the MD group and decreased until reaching values comparable to those of T0 at T60 (T0: 10.3 ± 2.3; T5: 14.5 ± 2.8; T60: 10.6 ± 1.9 %; p< 0.05 T5 vs T0 and T60). This trend of FMD change was observed in each subject. Insulin concentrations and HOMA-I decreased significantly at T5 and at T60 in both groups. Adiponectin and TNF-α concentrations remained unchanged in both groups throughout the study. Both IL-6 and 8-iso-PGF2α increased significantly at T5 in the AD group and decreased at T60 to values comparable to T0 (IL-6: T0 57.5 ± 9.0, T5 78.1 ± 10.9, T60 56.6 ± 6.8 pg/ml; T5 vs T0 p< 0,005, T5 vs T60 p< 0,02; 8-iso-PGF2α: T0 171.5 ± 30.6, T5 222.6 ± 35.1, T60 178.7 ± 25.8 pg/ml; T5 vs T0 p< 0,005, T5 vs T60 p< 0,02); no significant change was observed in the MD group. This study suggests that the hypocaloric low-carbohydrate diet induces a significant endothelial dysfunction in the short term (5-7 days) that is reverted in the middle term (2 months) as suggested by both the brachial artery FMD and serum markers of inflammation (IL-6) and oxidative stress (8-iso-PGF2α). On the contrary, the hypocaloric Mediterranean diet is able to improve the endothelial function at least in the short term. These effects are independent of body weight loss. Therefore, this study points out also the potential disadvantages of low-carbohydrate diets when prescribed (or self-prescribed) especially in subjects at high cardiovascular risk

Study of the magnetic penetration depth in RbOs_2O_6

Measurements of the magnetic field penetration depth \lambda in the pyrochlore superconductor RbOs_2O_6 (T_c\simeq6.3 K) were carried out by means of the muon-spin-rotation (\muSR) technique. At low temperatures \lambda^{-2}(T) saturates and becomes constant below T\simeq 0.2T_c, in agreement with what is expected for weak-coupled s-wave BCS superconductors. The value of \lambda at T=0 was found to be in the range of 250 nm to 300 nm. \muSR and equilibrium magnetization measurements both reveal that at low temperatures $\lambda$ is almost (at the level of 10%) independent of the applied magnetic field. This result suggests that the superconducting energy gap in RbOs_2O_6 is isotropic.Comment: 8 pages, 9 figure

Nanoscale Photoluminescence Manipulation in Monolithic Porous Silicon Oxide Microcavity Coated with Rhodamine-Labeled Polyelectrolyte via Electrostatic Nanoassembling

Porous silicon (PSi) is a promising material for future integrated nanophotonics when coupled with guest emitters, still facing challenges in terms of homogenous distribution and nanometric thickness of the emitter coating within the silicon nanostructure. Herein, it is shown that the nanopore surface of a porous silicon oxide (PSiO2) microcavity (MC) can be conformally coated with a uniform nm-thick layer of a cationic light-emitting polyelectrolyte, e.g., poly(allylamine hydrochloride) labeled with Rhodamine B (PAH-RhoB), leveraging the self-tuned electrostatic interaction of the positively-charged PAH-RhoB polymer and negatively-charged PSiO2 surface. It is found that the emission of PAH-RhoB in the PSiO2 MC is enhanced (≈2.5×) and narrowed (≈30×) at the resonant wavelength, compared with that of PAH-RhoB in a non-resonant PSiO2 reference structure. The time-resolved photoluminescence analysis highlights a shortening (≈20%) of the PAH-RhoB emission lifetime in the PSiO2 MC at the resonance versus off-resonance wavelengths, and with respect to the reference structure, thereby proving a significant variation of the radiative decay rate. Remarkably, an experimental Purcell factor Fp = 2.82 is achieved. This is further confirmed by the enhancement of the photoluminescence quantum yield of the PAH-RhoB in the PSiO2 MC with respect to the reference structure. Application of the electrostatic nanoassembling approach to other emitting dyes, nanomaterials, and nanophotonic systems is envisaged

Pressure effects on the transition temperature and the magnetic field penetration depth in the pyrochlore superconductor RbOs_2O_6

We report magnetization measurements under high hydrostatic pressure in the newly discovered pyrochlore superconductor RbOs_2O_6 (T_c\simeq6.3K at p=0). A pronounced and {\it positive} pressure effect (PE) on T_c with dT_c/dp =0.090(1)K/kbar was observed, whereas no PE on the magnetic penetration depth \lambda was detected. The relative pressure shift of T_c [ dlnT_c/dp \simeq 1.5%/kbar] is comparable with the highest values obtained for highly underdoped high-temperature cuprate superconductors. Our results suggest that RbOs_2O_6 is an adiabatic BCS-type superconductor.Comment: 11 pages, 4 figure