Volatile organic compounds sensing based on Bennet doubler-inspired triboelectric nanogenerator and machine learning-assisted ion mobility analysis.

Ion mobility analysis is a well-known analytical technique for identifying gas-phase compounds in fast-response gas-monitoring systems. However, the conventional plasma discharge system is bulky, operates at a high temperature, and inappropriate for volatile organic compounds (VOCs) concentration detection. Therefore, we report a machine learning (ML)-enhanced ion mobility analyzer with a triboelectric-based ionizer, which offers good ion mobility selectivity and VOC recognition ability with a small-sized device and non-strict operating environment. Based on the charge accumulation mechanism, a multi-switched manipulation triboelectric nanogenerator (SM-TENG) can provide a direct current (DC) bias at the order of a few hundred, which can be further leveraged as the power source to obtain a unique and repeatable discharge characteristic of different VOCs, and their mixtures, with a special tip-plate electrode configuration. Aiming to tackle the grand challenge in the detection of multiple VOCs, the ML-enhanced ion mobility analysis method was successfully demonstrated by extracting specific features automatically from ion mobility spectrometry data with ML algorithms, which significantly enhance the detection ability of the SM-TENG based VOC analyzer, showing a portable real-time VOC monitoring solution with rapid response and low power consumption for future internet of things based environmental monitoring applications.

Lab-on-Chip Platform for Culturing and Dynamic Evaluation of Cells Development.

This paper presents a full-featured microfluidic platform ensuring long-term culturing and behavioral analysis of the radically different biological micro-objects. The platform uses all-glass lab-chips and MEMS-based components providing dedicated micro-aquatic habitats for the cells, as well as their intentional disturbances on-chip. Specially developed software was implemented to characterize the micro-objects metrologically in terms of population growth and cells' size, shape, or migration activity. To date, the platform has been successfully applied for the culturing of freshwater microorganisms, fungi, cancer cells, and animal oocytes, showing their notable population growth, high mobility, and taxis mechanisms. For instance, circa 100% expansion of porcine oocytes cells, as well as nearly five-fold increase in E. gracilis population, has been achieved. These results are a good base to conduct further research on the platform versatile applications.

Development of a Thermoelectric and Electromagnetic Hybrid Energy Harvester from Water Flow in an Irrigation System.

A hybrid energy harvester is presented in this paper to harvest energy from water flow motion and temperature difference in an irrigating pipe at the same time. The harvester is based on the integration of thermoelectric and electromagnetic mechanisms. To harvest the water flow motion, a turbine fan with magnets that are attached on the blades is placed inside of the water pipe. Multiple coils turn the water flow energy into electricity with the rotation of the turbine. The thermoelectric generators (TEGs) are attached around the pipe, so as to harvest energy due to temperature difference. For a maximum temperature difference of 55 °C (hot side 80 °C and room temperature 25 °C), twelve serial-connected TEGs can generate voltage up to 0.346 V. Under a load resistance of 20 Ώ, the power output of 1.264 mW can be achieved. For a maximum water flow rate of 49.9 L/min, the electromagnetic generator (EMG) can produce an open circuit voltage of 0.911 V. The EMG can be potentially used as a water flow meter due to the linear relationship between water flow rate and output voltage. Under the joint action of TEG and EMG, the maximum terminal voltage for TEG is 66 mV and for EMG is 241 mV at load resistances of 10 and 100 Ώ, respectively, resulting in a corresponding power output of 0.435 and 0.584 mW.

Investigation of Position Sensing and Energy Harvesting of a Flexible Triboelectric Touch Pad.

Triboelectric nanogenerator (TENG) is a promising technology because it can harvest energy from the environment to enable self-sustainable mobile and wearable electronic devices. In this work, we present a flexible touch pad capable of detecting the contact location of an object and generating substantial energy simultaneously based on the coupling of triboelectric effects and electrostatic induction. The touch pad consists of Polytetrafluoroethylene (PTFE) thin film, multiple Aluminum (Al) electrodes and Polyethylene terephthalate (PET) layers, which can be achieved through low cost, simplified and scalable fabrication process. Different from the conventional multi-pixel-based positioning sensor (i.e., large array of sensing elements and electrodes), the analogue method proposed here is used to implement the positioning function with only four electrodes. Position location can achieve a detecting resolution of as small as 1.3 mm (the size of locating layer is 7.5 cm × 7.5 cm). For the energy harvesting part, a multilayer structure is designed to provide higher current output. The open circuit voltage of the device is around 420 V and the short circuit current can reach up to 6.26 µA with current density of 0.25 µA/cm². The maximum output power obtained is approximately 10 mW, which is 0.4 mW/cm². The flexibility and significantly reduced number of electrodes enable the proposed touch pad to be readily integrated into portable electronic devices, such as intelligent robots, laptops, healthcare devices, and environmental surveys, etc.

Study of the behavior of Euglena viridis, Euglena gracilis and Lepadella patella cultured in all-glass microaquarium.

In the paper, the microaquarium fabricated in a form of entirely glass lab-on-a-chip for culturing and microscale study of microorganisms has been presented. A new approach towards cellular studies that brings a significant improvement over commonly utilized - polymer-based solutions has been shown. For the first time, all-borosilicate glass chip was applied for the culturing of the selected microorganisms and enabled notable population growth and behaviorism investigation. The chip fabrication method in comparison to typical glass chip technology was notably simplified, including quick patterning and low temperature bonding in 80 °C. In the studies, both a single-cell (Euglena gracilis and Euglena viridis) and multi-cell microorganisms (Lepadella patella) were cultured in the microaquarium. Behaviorism of the selected microorganisms was investigated by supplying various proportions of carbon dioxide, nitrogen and air into the chip. Tests included studies of microorganisms chemotaxis, viability (mostly based on photosynthesis process) and coexistence in the lab-on-a-chip environment. The experiments confirmed that the developed chip is a tool that fits the requirements for the culturing and behavioral studies of microorganisms and constitute ground-works to propel its further application in broadly defined cellular study field.

Supravital fluorometric apoptosis detection in a single mouse embryo using lab-on-a-chip.

Detection of apoptosis is one of the main criteria of preimplantation embryo growth potential assessment. Recent developments in lab-on-a-chip techniques has led to apoptosis detection and monitoring on a single cell or embryo level. However, single embryo apoptosis detection without a change in embryo developmental competence and post-examination "recovery" still remains a challenge. In this paper we present a lab-on-a-chip, co-working with miniaturized optical instrumentation, which allows supravital examination of single embryos for the presence of apoptotic blastomers with full after lab-on-a-chip study "recovery" and maintenance of their further developmental capacity.

The SmartBioPhone, a point of care vision under development through two European projects: OPTOLABCARD and LABONFOIL.

This paper describes how sixteen partners from eight different countries across Europe are working together in two EU projects focused on the development of a point of care system. This system uses disposable Lab on a Chips (LOCs) that carry out the complete assay from sample preparation to result interpretation of raw samples. The LOC is either embedded in a flexible motherboard with the form of a smartcard (Labcard) or in a Skinpatch. The first project, OPTOLABCARD, extended and tested the use of a thick photoresit (SU-8) as a structural material to manufacture LOCs by lamination. This project produced several examples where SU-8 microfluidic circuitry revealed itself as a viable material for several applications, such as the integration on chip of a Polymerase Chain Reaction (PCR) that includes sample concentration, PCR amplification and optical detection of Salmonella spp. using clinical samples. The ongoing project, LABONFOIL, is using two results of OPTOLABCARD: the sample concentration method and the capability to fabricate flexible and ultra thin LOCs based on sheets instead of wafers. This rupture from the limited and expensive wafer surface heritage allows the development of a platform where LOCs are big enough to include all the sample preparation subcomponents at a low price. These LOCs will be used in four point of care applications: environment, food, cancer and drug monitoring. The user will obtain the results of the tests by connecting the Labcard/Skinpatch reader to a very popular interface (a smartphone), creating a new instrument namely "The SmartBioPhone". All standard smartphone capabilities will be at the disposal of the point of care instrument by a simple click. In order to guarantee the future mass production of these LOCs, the project will develop a large dry film equipment where LOCs will be fabricated at a low cost.