Thermal scanning probe lithography

Thermal scanning probe lithography (tSPL) is a nanofabrication method for the chemical and physical nanopatterning of a large variety of materials and polymer resists with a lateral resolution of 10 nm and a depth resolution of 1 nm. In this Primer, we describe the working principles of tSPL and highlight the characteristics that make it a powerful tool to locally and directly modify material properties in ambient conditions. We introduce the main features of tSPL, which can pattern surfaces by locally delivering heat using nanosized thermal probes. We define the most critical patterning parameters in tSPL and describe post-patterning analysis of the obtained results. The main sources of reproducibility issues related to the probe and the sample as well as the limitations of the tSPL technique are discussed together with mitigation strategies. The applications of tSPL covered in this Primer include those in biomedicine, nanomagnetism and nanoelectronics; specifically, we cover the fabrication of chemical gradients, tissue-mimetic surfaces, spin wave devices and field-effect transistors based on two-dimensional materials. Finally, we provide an outlook on new strategies that can improve tSPL for future research and the fabrication of next-generation devices

Metallic functionalization of magnetic nanoparticles enhances the selective removal of glyphosate, AMPA, and glufosinate from surface water

Glyphosate (GLY) is the most used herbicide worldwide, raising concerns due to its toxicity and mobility in water. The concurrent spread of similar herbicides, i.e., glufosinate (GLUF) and aminomethylphosphonic acid (AMPA, a metabolite of GLY), also causes a serious concern to the environment. The application of magnetic nanoparticles (MNPs) gained wide attention as a promising approach for the environmental remediation of GLY. However, the fast agglomeration, low removal efficiency, and saturation of MNPs by non-target chemicals remain a challenge. Herein, we used polydopamine as a coating agent followed by functionalization with different metal ions, i.e. Ti(iv), Zr(iv), and Cu(ii), for selective removal of GLY, AMPA, and GLUF from deionised water in laboratory trials. Finally, we tested the performance of MNPs in surface waters contaminated with GLY at 0.17 & PLUSMN; 0.02 & mu;g L-1. The GLY removal efficiency (RE, %) of MNPs was optimized by using different GLY to MNP ratios and incubation times, in the presence of GLY-analogues and competitive species, i.e., phosphates. The results indicate that all metallic functionalized MNPs are more stable toward aggregation and effective in removing GLY than bare MNPs, up to 150 & mu;g L-1. The optimal ratio was 500 & mu;g(GLY) g(MNPs)(-1) (50 & mu;g GLY to 100 mg MNP), with RE > 80%. MNPs functionalized with Ti(iv) and Zr(iv) performed more efficiently than MNPs functionalized with Cu(ii), reaching an RE of 99.9% after a incubation time of 15 min. The presence of Ti(iv) and Zr(iv) in the MNPs increased the selectivity of the particles toward GLY and GLY analogues that can be removed with similar efficiency, and prevented competition with phosphates at much higher concentrations (1000 & mu;g L-1). Finally, GLY analogues can be easily re-eluted with ammonia, and the functionalized MNPs can be efficiently re-used up to four cycles. The use of metal-functionalized MNPs is a promising approach for the removal of target pollutants from contaminated water

Guida alle macrofite acquatiche del Friuli Venezia Giulia I - Piante vascolari

La Direttiva Quadro sulle Acque (2000/60/CE), recepita in Italia dal DL. 152/2006, ha introdotto lo studio delle macrofite acquatiche nella valutazione dello stato ecologico delle acque interne, basato sui criteri tecnici del DM 260/2011. Per i corsi d'acqua è previsto l'uso dell'Indice Biologique Macrophytique en Rivière IBMR (AFNOR, 2003), per i laghi degli indici MTIspecies e MacroIMMI (CNR-ISE, 2009). La certificazione di qualità delle analisi biologiche richiede strumenti conoscitivi adeguati: la creazione di chiavi informatizzate è una tappa fondamentale. Questa guida è stata sviluppata dal Dipartimento di Scienze della Vita dell'Università di Trieste e da ARPA Friuli Venezia Giulia come supporto all'identificazione della flora acquatica regionale. Risulta dalla condivisione delle conoscenze dell'ateneo giuliano con l'esperienza dei tecnici ARPA FVG nell'ambito delle attività di biomonitoraggio per il Piano Regionale di Tutela delle Acque. Le macrofite acquatiche comprendono vegetali molto diversi: alghe macroscopicamente visibili, muschi, epatiche e piante vascolari, a cui è dedicata questa guida. L'elenco floristico comprende taxa tipici di ambienti lotici e lentici, creato in fasi successive. Una prima lista deriva dal confronto tra la quella utilizzata per il calcolo dell'IBMR e la lista delle macrofite acquatiche dei corsi d'acqua italiani pubblicata da ENEA (RT/2009/23/ENEA). La successiva comparazione tra i dati dell'Atlante Corologico del Friuli Venezia Giulia (Poldini 2002) ed una lista risultante da rilievi condotti nel 2009-2010 da ARPA FVG, hanno portato all'elenco di 244 taxa inclusi in questa guida. La suddivisione in Famiglie segue Angiosperm Phylogeny Group III (2009)

NALP3 inflammasome upregulation and CASP1 cleavage of the glucocorticoid receptor cause glucocorticoid resistance in leukemia cells

Glucocorticoids are universally used in the treatment of acute lymphoblastic leukemia (ALL), and resistance to glucocorticoids in leukemia cells confers poor prognosis. To elucidate mechanisms of glucocorticoid resistance, we determined the prednisolone sensitivity of primary leukemia cells from 444 patients newly diagnosed with ALL and found significantly higher expression of CASP1 (encoding caspase 1) and its activator NLRP3 in glucocorticoid-resistant leukemia cells, resulting from significantly lower somatic methylation of the CASP1 and NLRP3 promoters. Overexpression of CASP1 resulted in cleavage of the glucocorticoid receptor, diminished the glucocorticoid-induced transcriptional response and increased glucocorticoid resistance. Knockdown or inhibition of CASP1 significantly increased glucocorticoid receptor levels and mitigated glucocorticoid resistance in CASP1-overexpressing ALL. Our findings establish a new mechanism by which the NLRP3-CASP1 inflammasome modulates cellular levels of the glucocorticoid receptor and diminishes cell sensitivity to glucocorticoids. The broad impact on the glucocorticoid transcriptional response suggests that this mechanism could also modify glucocorticoid effects in other diseases

A Guide Inside Electrochemiluminescent Microscopy Mechanisms for Analytical Performance Improvement

ECL is luminescence generated by electrochemical reactions and for this reason it possesses better spatio-temporal control and low background in comparison with photoluminescence or other optical methods that rely on external light illumination.1–3 In the last 20 years ECL has proved to be a versatile and powerful analytical technique in different fields, ranging from fundamental research to commercial clinical and biological applications.4,5 The main reason behind its success is that ECL offers remarkable advantages in comparison to other transduction methods: high sensitivity, an extremely wide dynamic range, very low background signal, good temporal and spatial control, and insensitivity to matrix effects.6,7 Thanks to its simplified optical setup, ECL has been implemented as a powerful imaging technique to visualize electrochemical objects and entities bringing important insight in the ECL mechanism generation. Here we aim to incorporate all the work done in the field of ECL imaging mainly in the last three years with a particular focus on ECL generation mechanisms and their applications

Microscopic imaging and tuning of electrogenerated chemiluminescence with boron-doped diamond nanoelectrode arrays

Nanoelectrode arrays (NEAs) are increasingly applied for a variety of electroanalytical applications; however, very few studies dealt with the use of NEAs as an electrochemical generator of electrogenerated chemiluminescence (ECL). In the present study, arrays of nanodisc and nanoband electrodes with different dimensions and inter-electrode distances were fabricated by e-beam lithography on a polycarbonate layer deposited on boron-doped diamond (BDD) substrates. In particular, NEAs with 16 different geometries were fabricated on the same BDD sample substrate obtaining a multiple nanoelectrode and ultramicroelectrode array platform (MNEAP). After electrochemical and morphological characterization, the MNEAP was used to capture simultaneously with a single image the characteristic behaviour of ECL emission from all the 16 arrays. Experiments were performed using Ru(bpy)3 2+ as the ECL luminophore and tri-n-propylamine (TPrA) as the co-reactant. With a relatively limited number of experiments, such an imaging procedure allowed to study the role that geometrical and mechanistic parameters play on ECL generation at NEAs. In particular, at high concentrations of TPrA, well-separated individual ECL spots or bands revealed an ECL signal which forms a pattern matching the nanofabricated structure. The analysis of the imaging data indicated that the thickness of the ECL-emitting zone at each nanoelectrode scales inversely with the co-reactant concentration, while significantly stronger ECL signals were detected for NEAs operating under overlap conditions

BIOMOLECULE ANALYSIS METHOD AND BIOMOLECULE ANALYSIS DEVICE

This analysis method comprises: an inflow step for causing a solution to flow into a flow cell, said solution including a test substance, a magnetic support body having, formed on the surface thereof, a complex including an antibody that is for recognizing the test substance and is labeled with a luminescent agent, and a reaction aid for aiding in the reaction of the luminescent agent; a capturing step for capturing the magnetic support body on a working electrode using a magnetic field from a magnetic field generation device; a light emission step for causing the luminescent agent to emit light by applying a voltage to the working electrode; and a measurement step for measuring the amount of light emitted by the luminescent agent. The light emission step includes light emission caused by action on the luminescent agent of first neutral radicals produced from cationic radicals from the reaction aid and light emission caused by the action on the luminescent agent of second neutral radicals produced directly from the reaction aid. As a result, it is possible to increase ECL light emission efficiency and enhance detection sensitivity

Ultrasensitive PCR-Free detection of whole virus genome by electrochemiluminescence

Detection of nucleic acids is crucial in many medical applications, and in particular for monitoring infectious diseases, as it has become perfectly clear after the pandemic infection of COVID-19. In this context, the development of innovative detection methods based on signal-amplification rather than analyte-amplification represents a significant breakthrough compared to existing PCR-based methodologies, allowing the development of new nucleic acid detection technologies suitable to be integrated in portable and low-cost sensor devices while keeping high sensitivities, thus enabling massive diagnostic screening. In this work, we present a novel molecular sensor for the ultrasensitive PCR-free detection of Hepatitis B Virus (HBV) based on electrochemiluminescence (ECL). Thanks to the combination of surface cooperative hybridization scheme with ECL detection strategy, our novel DNA sensor is able to detect HBV genome – both synthetic and extracted – with the unprecedented limit of detection (LoD) of 0.05 cps μL 1 for extracted sample, that is even lower than the typical LoD of PCR methodologies. The detection concept presented here for HBV detection is very versatile and can be extended to other pathogens, paving the way for future development of rapid molecular test for infectious diseases, both viral and bacterial, in Point-of-Care (PoC) format

Giant Increase of Hardness in Silicon Carbide by Metastable Single Layer Diamond-Like Coating

: Silicon carbide (SiC) is one of the hardest known materials. Its exceptional mechanical properties combined with its high thermal conductivity make it a very attractive material for a variety of technological applications. Recently, it is discovered that two-layer epitaxial graphene films on SiC can undergo a pressure activated phase transition into a sp3 diamene structure at room temperature. Here, it is shown that epitaxial graphene films grown on SiC can increase the hardness of SiC up to 100% at low loads (up to 900 µN), and up to 30% at high loads (10 mN). By using a Berkovich diamond indenter and nanoindentation experiments, it is demonstrated that the 30% increase in hardness is present even for indentations depths of 175 nm, almost three hundred times larger than the graphene film thickness. The experiments also show that the yield point of SiC increases up to 77% when the SiC surface is coated with epitaxial graphene. These improved mechanical properties are explained with the formation of diamene under the indenter's pressure

A polymer canvas with the stiffness of the bone matrix to study and control mesenchymal stem cell response

: The possibility to reproduce in vitro the complex multiscale physical features present in the human tissues creates novel opportunities for biomedical advances and fundamental understanding of cell-environment interfaces and interactions. While stiffness has been recognized as a key property in influencing cell behavior, so far systematic studies on the role of stiffness have been limited to values in the KPa-MPa range, significantly below the stiffness of bone. Here, we report a platform enabling the tuning and control of the stiffness of a biocompatible polymeric interface up to values characteristic of the bone tissue, which are in the GPa range. The ability to fine tune the stiffness up to these large values is achieved by using extremely thin polymer films on glass and cross-linking the films using UV light irradiation. We show that a higher stiffness is related to better adhesion, proliferation, and osteogenic differentiation, and that it is also possible to switch on/off cell attachment and growth by solely tuning the stiffness of the interface, without any surface chemistry or topography modification. Since the stiffness is tuned directly by UV irradiation, this platform is ideal for rapid and simple stiffness patterning, and stiffness gradients fabrication. This materials platform represents an innovative tool for combinatorial studies of the synergistic effect of tissue environmental cues on cell behavior, and creates new opportunities for next generation biosensors, single-cell patterning, and lab-on-a-chip devices. This article is protected by copyright. All rights reserved