Electrochromic WO3 thin films attain unprecedented durability by potentiostatic pretreatment.

Electrochromic windows and glass facades are able to impart energy efficiency jointly with indoor comfort and convenience. Long-term durability is essential for practical implementation of this technology and has recently attracted broad interest. Here we show that a simple potentiostatic pretreatment of sputter-deposited thin films of amorphous WO3-the most widely studied electrochromic material-can yield unprecedented durability for charge exchange and optical modulation under harsh electrochemical cycling in a Li-ion-conducting electrolyte and effectively evades harmful trapping of Li. The pretreatment consisted of applying a voltage of 6.0 V vs. Li/Li+ for several hours to a film backed by a transparent conducting In2O3:Sn layer. Associated compositional and structural modifications were probed by several techniques, and improved durability was associated with elemental intermixing at the WO3/ITO and ITO/glass boundaries as well as with carbonaceous solid-electrolyte interfacial layers on the WO3 films. Our work provides important new insights into long-term durability of ion-exchange-based devices.

Diagnosis of Human Echinococcosis via Exhaled Breath Analysis: A Promise for Rapid Diagnosis of Infectious Diseases Caused by Helminths.

Background: Human echinococcosis is a neglected infectious disease affecting more than 1 million people globally. Its diagnosis is expensive and difficult because of lack of adequate resources in low-resource locations, where most cases occur. Methods: A group of volunteers diagnosed with the 2 main types of echinococcosis and corresponding control groups were recruited from hospitals in Tunisia (32 patients with cystic echinococcosis and 43 controls) and Poland (16 patients with alveolar echinococcosis and 8 controls). Breath samples were collected from all patients and analyzed by gas chromatography coupled to mass spectrometry, and a specifically developed electronic nose system. Results: The chemical analysis revealed statistically different concentrations of 2 compounds in the breath of patients with cystic echinococcosis compared to controls, and statistically different concentrations of 7 compounds in the breath of patients with alveolar echinococcosis compared to controls. The discrimination accuracy achieved by the electronic nose system was 100% for cystic echinococcosis and 92.9% for alveolar echinococcosis, while the discrimination accuracy between these 2 patient groups was 92.1%. Conclusion: Here we advocate a noninvasive, fast, easy-to-operate and nonexpensive diagnostic tool for the diagnosis of human echinococcosis disease through exhaled breath analysis, suitable for early diagnosis and population screening.

Ligand-Capped Ultrapure Metal Nanoparticle Sensors for the Detection of Cutaneous Leishmaniasis Disease in Exhaled Breath.

Human cutaneous leishmaniasis, although designated as one of the most neglected tropical diseases, remains underestimated due to its misdiagnosis. The diagnosis is mainly based on the microscopic detection of amastigote forms, isolation of the parasite, or the detection of Leishmania DNA, in addition to its differential clinical characterization; these tools are not always available in routine daily practice, and they are expensive and time-consuming. Here, we present a simple-to-use, noninvasive approach for human cutaneous leishmaniasis diagnosis, which is based on the analysis of volatile organic compounds in exhaled breath with an array of specifically designed chemical gas sensors. The study was realized on a group of n = 28 volunteers diagnosed with human cutaneous leishmaniasis and a group of n = 32 healthy controls, recruited in various sites from Tunisia, an endemic country of the disease. The classification success rate of human cutaneous leishmaniasis patients achieved by our sensors test was 98.2% accuracy, 96.4% sensitivity, and 100% specificity. Remarkably, one of the sensors, based on CuNPs functionalized with 2-mercaptobenzoxazole, yielded 100% accuracy, 100% sensitivity, and 100% specificity for human cutaneous leishmaniasis discrimination. While AuNPs have been the most extensively used in metal nanoparticle-ligand sensing films for breath sensing, our results demonstrate that chemical sensors based on ligand-capped CuNPs also hold great potential for breath volatile organic compounds detection. Additionally, the chemical analysis of the breath samples with gas chromatography coupled to mass spectrometry identified nine putative breath biomarkers for human cutaneous leishmaniasis.

Exhaled breath analysis for gastric cancer diagnosis in Colombian patients.

We present here the first study that directly correlates gastric cancer (GC) with specific biomarkers in the exhaled breath composition on a South American population, which registers one of the highest global incidence rates of gastric affections. Moreover, we demonstrate a novel solid state sensor that predicts correct GC diagnosis with 97% accuracy. Alveolar breath samples of 30 volunteers (patients diagnosed with gastric cancer and a controls group formed of patients diagnosed with other gastric diseases) were collected and analyzed by gas-chromatography/mass-spectrometry (GC-MS) and with an innovative chemical gas sensor based on gold nanoparticles (AuNP) functionalized with octadecylamine ligands. Our GC-MS analyses identified 6 volatile organic compounds that showed statistically significant differences between the cancer patients and the controls group. These compounds were different from those identified in previous studied performed on other populations with high incidence rates of this malady, such as China (representative for Eastern Asia region) and Latvia (representative for Baltic States), attributable to lifestyle, alimentation and genetics differences. A classification model based on principal component analysis of our sensor data responses to the breath samples yielded 97% accuracy, 100% sensitivity and 93% specificity. Our results suggest a new and non-intrusive methodology for early diagnosis of gastric cancer that may be deployed in regions lacking well-developed health care systems as a prediagnosis test for selecting the patients that should undergo deeper investigations (e.g., endoscopy and biopsy).

Fabrication and characterisation of ligand-functionalised ultrapure monodispersed metal nanoparticle nanoassemblies employing advanced gas deposition technique.

Here, we report for the first time the fabrication of ligand-functionalised ultrapure monodispersed metal nanoparticles (Au, Cu, and Pt) from their pure metal precursors using the advanced gas deposition technique. The experimental conditions during nanoparticle formation were adjusted in order to obtain ultrafine isolated nanoparticles on different substrates. The morphology and surface analysis of the as-deposited metal nanoparticles were investigated using scanning electron microscopy, x-ray diffraction and Fourier transform infra-red spectroscopy, which demonstrated the formation of highly ordered pure crystalline nanoparticles with a relatively uniform size distribution of ∼10 nm (Au), ∼4 nm (Cu) and ∼3 nm (Pt), respectively. A broad range of organic ligands containing thiol or amine functional groups were attached to the nanoparticles to form continuous networks of nanoparticle-ligand nanoassemblies, which were characterised by scanning electron microscopy and x-ray photoelectron spectroscopy. The electrical resistance of the functional nanoassemblies deposited in the gap spacing of two microfabricated parallel Au electrodes patterned on silicon substrates ranged between tens of kΩ and tens of MΩ, which is suitable for use in many applications including (bio)chemical sensors, surface-enhanced Raman spectroscopy and molecular electronic rectifiers.

Electrochemical Rejuvenation of Anodically Coloring Electrochromic Nickel Oxide Thin Films.

Nickel oxide thin films are of major importance as anodically coloring components in electrochromic smart windows with applications in energy-efficient buildings. However, the optical performance of these films degrades upon extended electrochemical cycling, which has hampered their implementation. Here, we use a potentiostatic treatment to rejuvenate degraded nickel oxide thin films immersed in electrolytes of LiClO4 in propylene carbonate. Time-of-flight elastic recoil detection analysis provided unambiguous evidence that both Li+ ions and chlorine-based ions participate in the rejuvenation process. Our work provides new perspectives for developing ion-exchange-based devices embodying nickel oxide.

Fluctuation-enhanced sensing with organically functionalized gold nanoparticle gas sensors targeting biomedical applications.

Detection of volatile organic compounds is a useful approach to non-invasive diagnosis of diseases through breath analysis. Our experimental study presents a newly developed prototype gas sensor, based on organically-functionalized gold nanoparticles, and results on formaldehyde detection using fluctuation-enhanced gas sensing. Formaldehyde was easily detected via intense fluctuations of the gas sensor's resistance, while the cross-influence of ethanol vapor (a confounding factor in exhaled breath, related to alcohol consumption) was negligible.

An optically powered CMOS tracking system for 3 T magnetic resonance environment.

In this work, a fully optical Complementary Metal Oxide Semiconductor (CMOS) based catheter tracking system designed for 3 T Magnetic Resonance Imaging (MRI) environment is presented. The system aims to solve the Radio Frequency (RF) induced heating problem present in conventional wired catheter tracking systems used in MRI. It is based on an integrated circuit, consisting of a receiver and an optical power supply unit. The optical power supply unit includes a single on-chip photodiode and a DC-DC converter that boosts the low photodiode voltage output to voltages greater than 1.5 V. Through an optically driven switch, the accumulated charge on an a storage capacitor is transferred to the rest of the system. This operation is novel in the way that it is fully optical and the switch control is done through modulation of the applied light. An on-chip local oscillator signal for the receiver is avoided by application of an RF signal that is generated by the MRI machine at the receiving period. The signals received by a micro-coil antenna are processed by the on-chip direct conversion receiver. The processed signal is then transferred, also optically, to the outside world for tracking purposes. The frequency encoding method is used for MRI tracking. Operation with various levels of external optical power does not generate noticeble temperature increase in the system. The overall system is successfully tested in a 3 T MRI machine to demonstrate its full operation.