28 research outputs found

    Toward Multi-Parametric Porous Silicon Transducers Based on Covalent Grafting of Graphene Oxide for Biosensing Applications

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    Graphene oxide (GO) is a two-dimensional material with peculiar photoluminescence emission and good dispersion in water, that make it an useful platform for the development of label-free optical biosensors. In this study, a GO-porous silicon (PSi) hybrid device is realized using a covalent chemical approach in order to obtain a stable support for biosensing applications. Protein A, used as bioprobe for biosensing purposes, is covalently linked to the GO, using the functional groups on its surface, by carbodiimide chemistry. Protein A bioconjugation to GO-PSi hybrid device is investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle (WCA) measurements, Fourier transform infrared (FTIR) spectroscopy, steady-state photoluminescence (PL), and fluorescence confocal microscopy. PSi reflectance and GO photoluminescence changes can thus be simultaneously exploited for monitoring biomolecule interactions as in a multi-parametric hybrid biosensing device

    PNA-based graphene oxide/porous silicon hybrid biosensor: towards a label-free optical assay for Brugada Syndrome

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    Peptide nucleic acid (PNA) is a synthetic DNA mimic that outperforms the properties of traditional oligonucleotides (ONs). On account of its outstanding features, such as remarkable binding affinity towards complementary DNA or RNA as well as high thermal and chemical stability, PNA has been proposed as a valuable alternative to the ON probe in gene-sensor design. In this study, a hybrid transducer made-up of graphene oxide (GO) nano-sheets covalently grafted onto a porous silicon (PSi) matrix has been investigated for the early detection of a genetic cardiac disorder, the Brugada syndrome (BS). A functionalization strategy towards the realization of a potential PNA-based device is described. A peptide nucleic acid (PNA), able to detect the SCN5A associated with the BS has been properly synthesized and used as a bioprobe for the realization of a proof-of-concept label-free optical PNA-biosensor. PSi reflectance and GO photoluminescence (PL) signals were simultaneously exploited for the monitoring of the device functionalization and response

    Risk factors associated with adverse fetal outcomes in pregnancies affected by Coronavirus disease 2019 (COVID-19): a secondary analysis of the WAPM study on COVID-19.

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    Objectives To evaluate the strength of association between maternal and pregnancy characteristics and the risk of adverse perinatal outcomes in pregnancies with laboratory confirmed COVID-19. Methods Secondary analysis of a multinational, cohort study on all consecutive pregnant women with laboratory-confirmed COVID-19 from February 1, 2020 to April 30, 2020 from 73 centers from 22 different countries. A confirmed case of COVID-19 was defined as a positive result on real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of nasal and pharyngeal swab specimens. The primary outcome was a composite adverse fetal outcome, defined as the presence of either abortion (pregnancy loss before 22 weeks of gestations), stillbirth (intrauterine fetal death after 22 weeks of gestation), neonatal death (death of a live-born infant within the first 28 days of life), and perinatal death (either stillbirth or neonatal death). Logistic regression analysis was performed to evaluate parameters independently associated with the primary outcome. Logistic regression was reported as odds ratio (OR) with 95% confidence interval (CI). Results Mean gestational age at diagnosis was 30.6+/-9.5 weeks, with 8.0% of women being diagnosed in the first, 22.2% in the second and 69.8% in the third trimester of pregnancy. There were six miscarriage (2.3%), six intrauterine device (IUD) (2.3) and 5 (2.0%) neonatal deaths, with an overall rate of perinatal death of 4.2% (11/265), thus resulting into 17 cases experiencing and 226 not experiencing composite adverse fetal outcome. Neither stillbirths nor neonatal deaths had congenital anomalies found at antenatal or postnatal evaluation. Furthermore, none of the cases experiencing IUD had signs of impending demise at arterial or venous Doppler. Neonatal deaths were all considered as prematurity-related adverse events. Of the 250 live-born neonates, one (0.4%) was found positive at RT-PCR pharyngeal swabs performed after delivery. The mother was tested positive during the third trimester of pregnancy. The newborn was asymptomatic and had negative RT-PCR test after 14 days of life. At logistic regression analysis, gestational age at diagnosis (OR: 0.85, 95% CI 0.8-0.9 per week increase; pPeer reviewe

    Risk Factors Associated with Adverse Fetal Outcomes in Pregnancies Affected by Coronavirus Disease 2019 (COVID-19): A Secondary Analysis of the WAPM study on COVID-19

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    To evaluate the strength of association between maternal and pregnancy characteristics and the risk of adverse perinatal outcomes in pregnancies with laboratory confirmed COVID-19. Secondary analysis of a multinational, cohort study on all consecutive pregnant women with laboratory-confirmed COVID-19 from February 1, 2020 to April 30, 2020 from 73 centers from 22 different countries. A confirmed case of COVID-19 was defined as a positive result on real-time reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assay of nasal and pharyngeal swab specimens. The primary outcome was a composite adverse fetal outcome, defined as the presence of either abortion (pregnancy loss before 22 weeks of gestations), stillbirth (intrauterine fetal death after 22 weeks of gestation), neonatal death (death of a live-born infant within the first 28 days of life), and perinatal death (either stillbirth or neonatal death). Logistic regression analysis was performed to evaluate parameters independently associated with the primary outcome. Logistic regression was reported as odds ratio (OR) with 95% confidence interval (CI). Mean gestational age at diagnosis was 30.6\ub19.5 weeks, with 8.0% of women being diagnosed in the first, 22.2% in the second and 69.8% in the third trimester of pregnancy. There were six miscarriage (2.3%), six intrauterine device (IUD) (2.3) and 5 (2.0%) neonatal deaths, with an overall rate of perinatal death of 4.2% (11/265), thus resulting into 17 cases experiencing and 226 not experiencing composite adverse fetal outcome. Neither stillbirths nor neonatal deaths had congenital anomalies found at antenatal or postnatal evaluation. Furthermore, none of the cases experiencing IUD had signs of impending demise at arterial or venous Doppler. Neonatal deaths were all considered as prematurity-related adverse events. Of the 250 live-born neonates, one (0.4%) was found positive at RT-PCR pharyngeal swabs performed after delivery. The mother was tested positive during the third trimester of pregnancy. The newborn was asymptomatic and had negative RT-PCR test after 14 days of life. At logistic regression analysis, gestational age at diagnosis (OR: 0.85, 95% CI 0.8-0.9 per week increase; p<0.001), birthweight (OR: 1.17, 95% CI 1.09-1.12.7 per 100 g decrease; p=0.012) and maternal ventilatory support, including either need for oxygen or CPAP (OR: 4.12, 95% CI 2.3-7.9; p=0.001) were independently associated with composite adverse fetal outcome. Early gestational age at infection, maternal ventilatory supports and low birthweight are the main determinants of adverse perinatal outcomes in fetuses with maternal COVID-19 infection. Conversely, the risk of vertical transmission seems negligible

    Photoemissive inorganic nanomaterials: characterization and their application in biophotonics

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    In the recent years, nanostructured materials have greatly sparked the interest of the scientific community: their small size and tunable functional properties make them appealing as tools for biomedical applications. In this perspective, the thesis work summarizes three years of research in the field of nanotechnology applied to life sciences. Specifically, three nanomaterials were studied and exploited as platforms for applications in biophotonics: porous silicon, graphene oxide and zinc oxide nanostructures. The common feature is herein given by the property of characteristic photoluminescence from inorganic nanostructures whose bulk counterpart exhibits negligible emission. The fields of bioimaging and optical biosensing were mostly explored. In the first case, several luminescent materials are exploitable such as organic dye molecules, nanoparticle clusters and quantum dots. The latter exhibit characteristic properties such as slow cooling of hot carriers and tunable absorption/emission via relatively simple processing techniques. Nevertheless, the crucial issue of the high toxicity of conventionally employed semiconductors (CdTe, CdSe) needs to be overcome and the fabrication of alternative nanostructures with efficient emission based on biocompatible materials is highly desirable. Besides, another promising path that can be followed is to combine materials with relevant optical properties, aiming at developing nanodevices with multi-parametric optical transduction so to further boosting the applicability in the biosensing field. In that, proper surface chemistry modification strategies can be designed to achieve multiple advantages: stabilization in physiological environment, improved biocompatibility, overall preservation of the optical behaviour as well as addition of functional groups, which may provide binding sites to anchor functional biomolecules. The experimental results showed that substantial improvements have been achieved in both the aforementioned contexts. In fact, the characterized and optimized nanoplatforms were successfully employed for biophotonic applications, which include in vivo time-gated imaging of Hydra vulgaris using luminescent silicon nanostructures as label-free probes and multi-parametric optical biosensing for early diagnostics, with focus on Brugada syndrome, based on on-chip porous silicon/graphene oxide nanocomposites

    On the regularity of very weak solutions for linear elliptic equations in divergence form

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    In this paper we consider a linear elliptic equation in divergence form ∑i,jDj(aij(x)Diu)=0in Ω. (0.1) Assuming the coefficients aij in W1,n(Ω) with a modulus of continuity satisfying a certain Dini-type continuity condition, we prove that any very weak solution u∈Lnâ€Čloc(Ω) of (0.1) is actually a weak solution in W1,2loc(Ω).peerReviewe

    Immune checkpoint inhibitors in combination with radiotherapy as salvage treatment for relapsed/refractory classical Hodgkin lymphoma: A retrospective analysis in 12 patients

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    12noThe rate of complete remission (CR) with the anti-PD1 immune checkpoint inhibitors (ICI) nivolumab (N) and pem-brolizumab (P) in patients with relapsed/refractory (R/R) classical Hodgkin lymphoma (cHL) is low (20-30%), and the majority of patients eventually relapse. One strategy to improve their outcome is to com-bine ICI with radiotherapy (ICI-RT), taking advantage of a supposed synergistic effect. We retrospectively collected data of 12 adult patients with R/R cHL treated with ICI-RT delivered during or within 8 weeks from the start or after the end of ICI. Median age at ICI-RT was 37 years, 50% had previously received an autologous stem cell transplantation (SCT) and 92% brentuximab vedotin. RT was given concurrently, before or after ICI in 4, 1 and 7 patients. Median RT dose was 30Gy, for a median duration of 22 days. Median number of ICI administrations was 15. Overall response and CR rate were 100% and 58%. Nine patients received sub-sequent SCT consolidation (7 allogeneic and 2 autologous). After a median follow-up of 18 months, 92% of patients were in CR. No major concerns about safety were reported. ICI-RT combination appears to be a feasible and highly active bridge treatment to transplant consolidation.openopenLucchini E.; Rusconi C.; Levis M.; Ricci F.; Santoro A.; Ricardi U.; Volpetti S.; Matrone F.; Di Russo A.; Caizzi M.; Schiattarella A.; Zaja F.Lucchini, E.; Rusconi, C.; Levis, M.; Ricci, F.; Santoro, A.; Ricardi, U.; Volpetti, S.; Matrone, F.; Di Russo, A.; Caizzi, M.; Schiattarella, A.; Zaja, F

    Near-field probes for sensitive detectorless near-field nanoscopy in the 2.0-4.6 THz range

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    Imaging and spectroscopy at terahertz (THz) frequencies have become key methods for fundamental studies across the physical sciences. With the emergence of nanoscale materials and devices, holding great promise for photonics, electronics, and communication technologies, the search for THz analysis at the nanoscale arises. Detectorless THz near-field nanoscopy emerged as a versatile method for hyperspectral mapping of light-matter interaction phenomena in bi-dimensional materials and systems. However, it is strongly limited by the weak scattering efficiencies of atomic force microscope (AFM) tips. Here, we experimentally evaluate the performance of unconventional AFM tip shapes to enhance the scattering efficiency, at three frequencies, namely, 2.0, 3.0, and 4.6 THz. The impact of tip geometry is corroborated by numerical simulations. The shorter shank length of the evaluated tips provides a very compelling alternative to commercial tips at frequencies &gt;2 THz.</p

    Hybrid Organic/Inorganic Nanomaterials for Biochemical Sensing

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    In this paper, different nanostructured semiconductors with advanced properties are explored for the realization of both optical and electrical biosensors for DNA detection. A hybrid sensor constituted by graphene oxide (GO) covalently grafted on a porous silicon (PSi) matrix is realized. A peptide nucleic acid (PNA) probe, able to recognize its complementary DNA (c-DNA) sequence, is immobilized on the surface of PSi/GO device for label-free optical sensing. Electrical sensing of DNA is also demonstrated using a Zinc Oxide Nanowires (ZnONWs) sensor functionalized with PNA probe; the I–V characteristic of the device depends on the c-DNA concentration under analysis
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