Overview of Gas Sensors Focusing on Chemoresistive Ones for Cancer Detection

The necessity of detecting and recognizing gases is crucial in many research and application fields, boosting, in the last years, their continuously evolving technology. The basic detection principle of gas sensors relies on the conversion of gas concentration changes into a readable signal that can be analyzed to calibrate sensors to detect specific gases or mixtures. The large variety of gas sensor types is here examined in detail, along with an accurate description of their fundamental characteristics and functioning principles, classified based on their working mechanisms (electrochemical, resonant, optical, chemoresistive, capacitive, and catalytic). This review is particularly focused on chemoresistive sensors, whose electrical resistance changes because of chemical reactions between the gas and the sensor surface, and, in particular, we focus on the ones developed by us and their applications in the medical field as an example of the technological transfer of this technology to medicine. Nowadays, chemoresistive sensors are, in fact, strong candidates for the implementation of devices for the screening and monitoring of tumors (the second worldwide cause of death, with ~9 million deaths) and other pathologies, with promising future perspectives that are briefly discussed as well

Chemoresistive Nanosensors Employed to Detect Blood Tumor Markers in Patients Affected by Colorectal Cancer in a One-Year Follow Up

Simple Summary Since colorectal cancer represents one of the most diffused pathologies worldwide, usually lacking specific symptoms, it is crucial to develop and validate innovative low-invasive techniques to detect it. Here, a device based on an array of nanostructured gas sensors has been employed to analyze and discriminate the exhalations of blood samples collected from colorectal cancer-affected patients at different stages of their pre- and post-surgery therapeutic path. The device was clearly able to distinguish between the pre-surgery samples, where the tumor was present, and the one-year post-surgery ones, following the tumor removal. These results raise high hopes for the device's clinical validation and its future use in clinical follow-up protocols, patient health status monitoring, and to detect possible post-treatment relapses. Colorectal cancer (CRC) represents 10% of the annual tumor diagnosis and deaths occurring worldwide. Given the lack of specific symptoms, which could determine a late diagnosis, the research for specific CRC biomarkers and for innovative low-invasive methods to detect them is crucial. Therefore, on the basis of previously published results, some volatile organic compounds (VOCs), detectable through gas sensors, resulted in particularly promising CRC biomarkers, making these sensors suitable candidates to be employed in CRC screening devices. A new device was employed here to analyze the exhalations of blood samples collected from CRC-affected patients at different stages of their pre- and post-surgery therapeutic path, in order to assess the sensor's capability for discriminating among these samples. The stages considered were: the same day of the surgical treatment (T1); before the hospital discharge (T2); after one month and after 10-12 months from surgery (T3 and T4, respectively). This device, equipped with four different sensors based on different metal-oxide mixtures, enabled a distinction between T1 and T4 with a sensitivity and specificity of 93% and 82%, respectively, making it suitable for clinical follow-up protocols, patient health status monitoring and to detect possible post-treatment relapses

Reproducibility and Repeatability Tests on (SnTiNb)O2 Sensors in Detecting ppm-Concentrations of CO and Up to 40% of Humidity: A Statistical Approach

: Nowadays, most medical-diagnostic, environmental monitoring, etc. devices employ sensors whose fabrication reproducibility and response repeatability assessment are crucial. The former consists of large-scale sensor manufacture through a standardized process with almost identical morphology and behavior, while the latter consists of giving the same response upon repeating the same stimulus. The thermo-activated chemoresistive sensors, which change their conductance by interacting with the molecules composing the surrounding gas, are currently employed in many devices: in particular, thick-film (SnTiNb)O2 nanosensors were demonstrated to be particularly suitable in the medical and biological fields. Therefore, a set of thirteen of them, randomly selected from the same screen-printing deposition, were laboratory tested, and the outcomes were statistically analyzed in order to assess their consistency. At first, the working temperature that maximized both the sensor sensitivity and response repeatability was identified. Then, the sensors were subjected to different gas concentrations and humidities at this optimal working temperature. It resulted in the (SnTiNb)O2 nanosensors detecting and discriminating CO concentrations as low as 1 ppm and at high humidity degrees (up to 40%) with high repeatability since the response relative standard error ranged from 0.8 to 3.3% for CO and from 3.6 to 5.4% for water vapor

New onset of chest pain: the importance of remote monitoring

Left ventricular (LV) dysfunction is found in about 20–30% of patients with atrial fibrillation (AF). Conversely, AF occurrence can deteriorate LV function determining severe LV dysfunction.1 Moreover, symptoms of heart failure (HF) like dyspnoea or chest pain may be related to AF occurrence without more specific symptoms like palpitations.1 Finally, devices like implantable cardioverter-defibrillator (ICD) may register atrial high-rate episodes (AHREs), which can last for more than 5 or 6 min and are also called subclinical AF. The clinical management of these episodes is still controversial. Rhythm vs. rate control strategies is still a matter of debate. Evidences regarding the use of oral anticoagulation in patients with AHRE are scarce. Therefore, AF needs to be confirmed either by surface electrocardiogram (ECG) or by intracardiac electrograms

Single lead catheter of implantable cardioverter-defibrillator with floating atrial sensing dipole implanted via persistent left superior vena cava

Persistent left superior vena cava (LSVC) is a congenital anomaly with 0.3%-1% prevalence in the general population. It is usually asymptomatic but in case of transvenous lead positioning, i.e., for pacemaker or implantable cardioverter defibrillator (ICD), may be a cause for significant complications or unsuccessful implantation. Single lead ICD with atrial sensing dipole (ICD DX) is a safe and functional technology in patients without congenital abnormalities. We provide a review of the literature and a case report of successful implantation of an ICD DX in a patient with LSVC and its efficacy in treating ventricular arrhythmias

Reply

Repl

A strain gradient approach to the analysis of nanoarches: Formulation and numerical solution with NURBS interpolation

Size effects observed in the mechanical behavior of micro- and nanostructures cannot be modeled by means of classical continuum mechanics. Enhanced continuum models based on nonlocal integro-differential or higher-order differential formulations have shown, on the contrary, that size effect can be modeled when appropriate modifications to the constitutive model are considered. The use of these models has been rapidily growing but their application to nanoarches appears not to have been fully investigated so far. In this contribution, we focus on a strain gradient formulation for thin arches. NURBS interpolations are considered in order to satisfy the high-order continuity requirement imposed by the strain gradient formulation and to interpolate the exact geometry of circular nanobeam

Current role of echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment for patients with heart failure and left ventricular systolic dysfunction. Patients are usually assessed by echocardiography, which provides a number of anatomical and functional information used for cardiac dyssynchrony assessment, prognostic stratification, identification of the optimal site of pacing in the left ventricle, optimization of the CRT device, and patient follow-up. Compared to other cardiac imaging techniques, echocardiography has the advantage to be non-invasive, repeatable, and safe, without exposure to ionizing radiation or nefrotoxic contrast. In this article, we review current evidence about the role of echocardiography before, during, and after the implantation of a CRT device

Reproducibility and Repeatability Tests on (SnTiNb)O2 Sensors in Detecting ppm-Concentrations of CO and Up to 40% of Humidity: A Statistical Approach

Nowadays, most medical-diagnostic, environmental monitoring, etc. devices employ sensors whose fabrication reproducibility and response repeatability assessment are crucial. The former consists of large-scale sensor manufacture through a standardized process with almost identical morphology and behavior, while the latter consists of giving the same response upon repeating the same stimulus. The thermo-activated chemoresistive sensors, which change their conductance by interacting with the molecules composing the surrounding gas, are currently employed in many devices: in particular, thick-film (SnTiNb)O2 nanosensors were demonstrated to be particularly suitable in the medical and biological fields. Therefore, a set of thirteen of them, randomly selected from the same screen-printing deposition, were laboratory tested, and the outcomes were statistically analyzed in order to assess their consistency. At first, the working temperature that maximized both the sensor sensitivity and response repeatability was identified. Then, the sensors were subjected to different gas concentrations and humidities at this optimal working temperature. It resulted in the (SnTiNb)O2 nanosensors detecting and discriminating CO concentrations as low as 1 ppm and at high humidity degrees (up to 40%) with high repeatability since the response relative standard error ranged from 0.8 to 3.3% for CO and from 3.6 to 5.4% for water vapor

Frequency of “Pocket” Hematoma in Patients Receiving Vitamin K Antagonist and Antiplatelet Therapy at the Time of Pacemaker or Cardioverter Defibrillator Implantation (from the POCKET Study)

In patients undergoing cardiac device implantation, anticoagulant and antiplatelet therapy are associated with an increased risk of pocket hematoma. In case of vitamin K antagonist therapy, a strategy of continued warfarin with no heparin bridge showed a reduction of pocket hematoma. Evidence regarding antiplatelet therapy management is limited. This is a single-center observational study which reflects our systematic approach to the problem. In 2012, we proposed an improved management protocol for anticoagulant and antiplatelet therapy (no-bridge protocol) based on individual thromboembolic risk stratification, noninterruption of oral anticoagulation, no bridge with heparin and elastic adherence compression bandage. The primary end point was the incidence of clinically significant pocket hematoma in the first 30 days after implantation. A total of 1,035 patients were enrolled, of whom 522 received the standard management and 513 the new protocol. The primary end point occurred in 34 patients of the standard management group and 8 patients of the no-bridge protocol group (6.5% vs 1.6%, p <0.001). Patients in the standard management group had a higher incidence of pocket infections (2.3% vs 0.6%, p = 0.02), lead dislodgements (4.8% vs 2.1%, p = 0.02), and thromboembolic events (1.3% vs 0.0%, p <0.01). On a multivariate analysis, heparin and coronary artery disease were independent predictors of pocket hematoma (relative risk [RR] 3.48, 95% confidence interval [CI] 1.55 to 7.83 and RR 2.43, 95% CI 1.25 to 4.76, respectively), whereas the no-bridge protocol was associated with a reduction of pocket hematoma (RR 0.33, 95% CI 0.14 to 0.76). New anticoagulant and antiplatelet therapy management protocol was associated with a reduced incidence of clinically significant pocket hematomas, thromboembolic events, pocket infections, and lead dislodgements