bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly-Stable Li Ion Batteries Based on Porous Si Anode and Localized High Concentration Electrolytes
Authors: Yi Ran , Chae Sujong , Li Qiuyan , Li Xiaolin , Zhang Ji-Guang
Published: May 2020

Si is one of the most promising anode materials for the next generation of lithium (Li) ion batteries (LIBs). Stability of Si based anode mainly depends on two factors: one is a stable nano-structure of Si which can tolerate large volume expansion/shrinking during Li injection/extraction process, another is a stable SEI layer formed in Si surface which are mechanically stable during cycling process. In this work, we report a scalable approach to prepare nano-structured Si particles in combination with a highly stable SEI layer formed in Localized High Concentration Electrolytes (LHCE) tailored for Si based LIBs. Comparing with the similar Si based anode materials available commercially, the new nano-Si based anode developed in this work exhibits a more than 20% improvement in cycle life (80% capacity retention) when the baseline electrolyte (1.2 M LiPF6 in EC-EMC (3:7 by wt.) +10 wt.% FEC) is used. Comparing with the baseline electrolyte, the new electrolytes developed in this work enabled a more then 30% increase in cycle life when the same anode material was used. These electrolytes are stable with both Si based anode and high voltage cathode such as Ni rich LiNixCoyMn1-x-yO2 (x ≥ 0.6), LiCoO2 etc. Therefore, they have great potential for both electrical vehicles and consumer electronics applications.
Novel Methods for Coating Li4Ti5O12 Particles: Boosting Performances of Li-Ion Batteries
Authors: Daigle Jean-Christophe , Asakawa Yuichiro , Beaupré Mélanie , Trudeau Michel , Zaghib Karim
Published: May 2020

One of the promising approaches for limiting climate changes is to use alternatives and greener sources of energy (wind, solar, etc.). However, the production of electricity from these sources is fluctuant and needs a solution for storage thus, the advent of energy storage for wind power, solar plant, etc., requires a new generation of batteries in order to optimize the use of these alternative sources of energy. To do so, the development of a battery with a high rate of charging and discharging, a longer cycle life and safe is imperative.

We devoted our efforts to develop LFP-LTO batteries; this presentation will highlight our avenues to limit the gas evolution in a battery; novel methods for coating will be presented, the use of polymers to protect the surface of the active inorganic particles in order to limit the degradation of the electrolyte. Two methods to graft polymers on particles (LTO) were applied with success for preventing degradation of LFP-LTO cells. Because battery environments are aggressive (HF formation, pH = 2), we developed a new robust method for grafting hydrophobic polymers on active particles (LTO) by Williamson Ether Synthesis, which is compatible with the manufacturing of electrodes, and prevented significant cell degradation over extensive cycling. They were able to limit the degradation of the battery by increasing the capacity retention and stabilizing the resistance of the electrode with the accelerated aging. The other method (grafting from) allows the formation of shells by a myriad of polymers, therefore particles become compatible with any kind of polymeric binders. Electrochemical performances will be shown with different compositions.

Moreover, we reported on the development of an economical, eco-friendly, and scalable method of making a homogenous 3D network coating of N-doped carbons on LTO particles. Our method makes it possible, for the first time, to fill the pores of secondary particles with carbons; we revealed that it is possible to cover each primary nanoparticle. This unique approach permited the creation of lithium-ion batteries with outstanding performances during ultra-fast charging (4 C and 10 C), and demonstrated an excellent ability to inhibit the degradation of cells over time. This new method allowed removal of conductive carbons in anode fabrication, therefore active materials compose up to 96 wt% in electrodes.

These methods are valuable for large production because it is inexpensive and easy to scale up.
Pulsed Current Based Fast Charging Methods for Li-Ion Battery
Authors: Khatokar Amarnath Rakesh , Thivel Pierre-Xavier , Leprêtre Jean-Claude , Bultel Yann , Roy Francis , Thorner Gentien
Published: May 2020

The increasing rate of greenhouse gas emissions from conventional cars and its impact on global warming in the recent years has led to the technological advancements in the evolution of electric vehicles. Developing fast charging methods for Li-ion batteries is one such technological advancement and soon it will be imperative to promote the usage of electric vehicles in increased numbers. However, fast charging of Li-ion battery accelerates aging mechanisms [1] and triggers thermal runaway condition. As a result, this study investigates pulsed current based fast charging methods employed on C/NMC batteries. Pulses of current at low frequency (mHz) [2] and high frequency (KHz) are used with an extended pulse current period, thanks to higher voltage limit based on ohmic drop compensation [3]. The findings of the experimental investigation clearly establishes that a compromise has to be found between relaxation period and temperature in order to achieve fast charging. For instance, on one hand, a 2C current pulse with an on duration of 3s and relaxation duration of 1s allows to save 45% of recharging time when compared with standard constant current-constant voltage charging (CC-CV) at 0.5C as shown in the figure below. On the other hand, the temperature variation does not exceed 20°C beyond ambient which is lower than that of its counterpart CC-CV at 2C. Hence, the experimental investigation successfully opens the doors to implement fast charging methods on C/NMC batteries by limiting the temperature rise, there by arresting the ageing of batteries and thermal runaway condition.

Keyword: Li-ion, Fast charging, Current pulse, Ohmic drop compensation, Temperature, Thermal runaway.

Figure 1
Design Considerations for Charging Time Reduction in Lithium Ion Cells
Authors: Yourey William , Fu Yanbao , Li Ning , Battaglia Vince , Tong Wei
Published: May 2020

As electric vehicles (EV) show an increased penetration into the transportation market, a challenging hurdle to overcome is a vehicle “refuel” time similar to that of refilling a gasoline vehicle tank. One pathway to accomplish this is fast charging lithium-ion cells. The majority of commercial Li-Ion cells manufactured today contain various positive electrode active materials, coupled with a graphite negative electrode. An advantage of graphite electrodes is that the lithiated graphite voltage lies close to that of Li/Li+, resulting in in increased cell voltage. This benefit also has a detrimental effect on fast charging cells with graphite electrodes, where a small polarization of the negative electrode can result in a condition favorable to lithium metal plating on the negative graphite electrodes1.

While modified high rate charging procedures for commercial lithium-ion cells with conventional graphite negative electrodes, such as multistage constant current charging and boost charging, have been implemented. These procedures rely on reducing charging currents when cell voltage limits are reached 2,3. Following the development of an accelerated charging procedure based solely on negative electrode lithiation rate and polarization 4, the presented work evaluates the effect of negative to positive (N:P) matching ratio on cell fast charge performance. Two varying N:P matching ratios of 1.2:1 and 1.7:1 are evaluated and the resulted impact on fast charge performance will be presented. Utilizing an accelerated charging procedure based solely on the limiting negative electrode results in an identical charging procedure being used for multiple cell designs when charging to the same degree of negative electrode lithiation. Theoretically the applied procedure should result in a reduction in recharge time to 80% state of charge from 58 minutes to 34 minutes by altering the cell N:P ratio. Actual cell performance is altered as increased irreversible capacity loss occurs in cells with increased N:P rations, but improvements in cell charge times can be accomplished from design changes, namely cell N:P ratios.

References

1. C. Uhlmann, J. Illig, M. Ender, R. Schuster, and E. Ivers-Tiffée, Journal of Power Sources, 279, 428–438 (2015).

2. D. Anseán et al., Journal of Power Sources, 321, 201–209 (2016).

3. P. H. L. Notten, J. H. G. O. het Veld, and J. R. G. van Beek, Journal of Power Sources, 145, 89–94 (2005).

4. W. Yourey, Y. Fu, N. Li, V. Battaglia, and W. Tong, J. Electrochem. Soc., 166, A1432–A1438 (2019).
Accurate in-Operando Quantitative Diagnostics of Lithium Ion Cells Using Heat Generation
Authors: Prosser Ryan
Published: May 2020

As lithium ion cells are used, internal chemical and physical degradation processes occur which negatively impact cell performance. A key issue for battery systems engineers is extending the life of their battery pack which amounts to slowing down the rate of these degradation processes.

The first step in addressing this problem is being able to frequently and accurately diagnose cell degradation. With this knowledge of cell state, it is possible to make better decisions on how to adjust the operating conditions of the battery pack to optimise cell longevity and performance.

Current methods which are capable of accurate quantitative diagnostics employ thermodynamic models parameterised by different degradation modes. These models require very slow discharge rates or galvanic intermittent titration tests (GITT) to obtain the cell open circuit voltage (OCV) and therefore cannot be used in most commercial applications. Other methods which do not require OCV conditions involve an impedance model coupled to the thermodynamic model. This adds computational complexity of the methods as well as incurring an accuracy penalty compared to the thermodynamic models.

We present a novel technique which uses cell instantaneous heat generation rate obtained in operando to quantify the extent of cell degradation. The proposed method provides results comparable to those obtained from thermodynamic models using a model which is no more computationally intense. The method also decouples the thermodynamic and kinetic effects of degradation allowing for a full diagnosis to be obtained more accurately and in a fraction of the time compared to alternative methods.
(Invited) Self-Powered Heavy Metal Sensors Based on Triboelectric and Thermoelectric Effects
Authors: Lin Zong-Hong
Published: May 2020

Self-powered sensors have shown their superior advantages and become more popular when comparing to other traditional sensing technologies. In the past years, we have developed self-powered sensors based on triboelectric and thermoelectric effects for the detection of metal ions and small molecules. In those self-powered sensors, functional nanomaterials will act as core materials to spontaneously generate electric outputs by environmental mechanical motions or temperature differences as well as recognition elements for highly specific reaction with mercury ions. For example, those self-powered sensors can provide a high sensitivity (LOD of 1.7 nM) and good linear range (from 10 nM to 1 mM) toward mercury ion detection. The selectivity of those self-powered sensors is also evaluated. Among the investigated metal ions, only Hg2+ ions result in a distinct output voltage change, by approximately 9 times. Those self-powered sensors exhibit the capability to clearly distinguish even a small concentration of Hg2+ ions from the presence of various other species in environmental samples. With the simplicity (no complex circuitry or power supply involved) and low-cost fabrication mechanism (small-sized; minimal and low-priced materials required), those self-powered sensors demonstrate great potential to serve as new prototypes of portable devices for the in-field sensing of samples
(Invited) Multi-Functional Flexible Sensor Sheets
Authors: Takei Kuniharu
Published: May 2020

Flexible and stretchable electronics are now widely studied for a next class of electric devices replaced from the silicon-based conventional inflexible devices. In particular, multi-functional e-skins can contribute to the applications for wearable healthcare devices and Internet of Things (IoT) concepts. For healthcare application, chemical information such as pH, glucose, sodium ion, and potassium ion levels are very important to monitor as well as physical information including activity, temperature, heartbeat, and electrocardiogram (ECG) signals. Furthermore, simultaneous multiple condition monitoring of physical and chemical information is a next class of wearable devices for convenient and safe human life. To realize the multi-functional flexible sensor system platforms, in this talk, flexible physical and chemical sensor sheets using mainly inorganic nanomaterials will be discussed by proposing low-cost, macroscale, and multi-functional material systems. Especially, human-interactive flexible sensors to detect human motion and health conditions are mainly introduced. After understanding the fundamental properties and mechanism of the flexible sensors such as a strain sensor, a temperature sensor, an ultraviolet sensor, a tactile pressure sensor, and a chemical sensor, integrated device applications with several sensors on a flexible film are demonstrated as proof-of-concepts for multi-functional e-skins.

Although a lot of researches and developments are still required for practical application, these studies may help to open a door for the next step of flexible electronics.
(Invited) Smart Textiles for Personalized Health Care
Authors: Chen Jun
Published: May 2020

There is nothing more personal than healthcare. Health care must move from its current reactive and disease-centric system to a personalized, predictive, preventative and participatory model with a focus on disease prevention and health promotion. As the world marches into the era of Internet of Things (IoT) and 5G wireless, technology renovation enables industry to offer a more individually tailored approach to healthcare with more successful health outcomes, higher quality and lower costs. However, empowering the utility of IoT enabled technology in personalized health care is still significantly challenged by the shortage of cost-effective and wearable biomedical devices to continuously provide real-time, patient-generated health data. Textiles have been concomitant and playing a vital role in the long history of human civilization. In this talk, I will introduce my research on smart textiles for biomedical monitoring and personalized diagnosis, textile for therapy, and textile power generation as an energy solution for the future wearable medical devices.
(Invited) Wireless Electrochemiluminescence Devices
Authors: Gao Wenyue , Qi Wenjing , Qi Liming , Yuan Fan , Ma Xiangui , Xia Yong , Zhang Wei , Lou Baohua , Muzyka Kateryna , Snizhko Dmytro V. , Xu Guobao
Published: May 2020

Traditional electrochemical systems generally require the direct connection of working electrode with potentiostat. They often employ two electrodes (a working electrode and a counter electrode) or three electrodes (a working electrode, a counter electrode, and a reference electrode) for a single electrochemical experiment. Different from traditional electrochemical systems, wireless electrochemical systems do not require the direct connection of working electrode with potentiostat. Conventional ipolar electrochemical system is a well-known wireless electrochemical system. It exerts potential control over electrolyte solutions with driving electrodes and redox reactions occur at the two opposite poles of the bipolar electrode. This enables simultaneous control of many bipolar electrode arrays with only two driving electrodes for multiplex experiments.

Electrochemiluminescence, also called electrogenerated chemiluminescence (ECL), is light-emitting phenomenon generated from electrochemical reaction. The combination of bipolar electrochemical systems with ECL enables facile multiplex analysis.

We present here several new wireless ECL systems, including wireless electrochemiluminescence, single-electrode ECL system, and wireless single-electrode ECL system [1-5].

Acknowledgment

We are grateful for financial support from the National Key Research and Development Program of China (No. 2016YFA0201300), National Natural Science Foundation of China (Nos. 21804127,21874126,21675148), the Chinese Academy of Sciences (CAS)-the Academy of Sciences for the Developing World (TWAS), and President’s Fellowship Program, the CAS President's International Fellowship Initiative (PIFI) project.

References

Wenjing Qi, Jianping Lai, Wenyue Gao, Suping Li, Saima Hanif, Guobao Xu. Wireless Electrochemiluminescence with Disposable Minidevice. Chem., 2014, 86, 8927–8931.

Liming Qi, Yong Xia, Wenjing Qi, Wenyue Gao, Fengxia Wu, Guobao Xu. Increasing Electrochemiluminescence Intensity of a Wireless Electrode Array Chip by Thousands of Times Using a Diode for Sensitive Visual Detection by a Digital Camera Chem., 2016, 88, 1123–1127.

Fan Yuan, Liming Qi, Tadesse Haile Fereja, Dmytro V. Snizhko, Zhongyuan Liu, Wei Zhang, Guobao Xu. Regenerable bipolar electrochemiluminescence device using glassy carbon bipolar electrode, stainless steel driving electrode and cold patch. Electroc Acta, 2018, 262, 182-186.

Xiangui Ma, Liming Qi, Wenyue Gao, Fan Yuan, Yong Xia, Baohua Lou, Guobao Xu. A portable wireless single-electrode system for electrochemiluminescent analysis. Electroc Acta, 2019, 308, 20-24.

Wenyue Gao, Kateryna Muzyka, Xiangui Ma, Baohua Lou, Guobao Xu, A single-electrode electrochemical system for multiplex electrochemiluminescence analysis based on a resistance induced potential difference. Chem. Sci. 2018, 9, 3911-3916.
(Invited) Structural Modulation of 2D Carbon Nitride for Electrochemiluminescent Biosensing
Authors: Zhang Yuanjian
Published: May 2020

As an emerging luminophore, metal free 2D carbon nitride demonstrate the advantages of low-cost, high biocompatibility and stability, easy functionalization, strong electrochemiluminescent (ECL) emission, and an unambiguous luminescence mechanism. Many ECL biosensors based on carbon nitride have been developed, with very promising performances. As chemical tailoring of 2D materials can effectively control the properties thus guiding their applications, our group recently explored the modulation of a diverse range of carbon nitrides with different dopants and nanostructures (e.g. nanosheets, nanofibers, and quantum dots). It not only tunes the optical properties of carbon nitride but also offer an effective way to engineer the surface properties of carbon nitride. Both are important in addressing the challenges of biosensing such as the development of new strategies for higher sensitivity and selectivity that involves signal transducer and multi-scale interfaces.

Acknowledgements

This work was financially supported in part by the National Natural Science Foundation of China (21775018), the Natural Science Foundation of Jiangsu Province (BK20160028), the Open Funds of the State Key Laboratory of Electroanalytical Chemistry (SKLEAC201909) and the Fundamental Research Funds for the Central Universities.

References

[1]Zhou, Z.; Zhang, Y.; Shen, Y.; Liu, S.; Zhang, Y. Chem. Soc. Rev.
2018, 47, 2298.

[2] Zhao, T.; Zhou, Q.; Lv, Y.; Han, D.; Wu, K.; Zhao, L.; Shen, Y.; Liu, S.; Zhang, Y., Angew. Chem. Int. Ed.
2019, DOI: 10.1002/anie.201911822.

[3] Lv, Y.; Chen, S.; Shen, Y.; Ji, J.; Zhou, Q.; Liu, S.; Zhang, Y. J. Am. Chem. Soc.
2018,
140, 2801.

[4] Ji, J.; Wen, J.; Shen, Y.; Lv, Y.; Chen, Y.; Liu, S.; Ma, H.; Zhang, Y. J. Am. Chem. Soc. 2017, 139, 11698.

[5] Zhou, Z.; Wang, J.; Yu, J.; Shen, Y.; Li, Y.; Liu, A.; Liu, S.; Zhang, Y. J. Am. Chem. Soc. 2015, 137, 2179.
(Invited) Plasmon-Enhanced Sensors Using Heterogeneous Films
Authors: Yang Yang
Published: May 2020

Using localized surface plasmon resonance (LSPR) from novel metal nanoparticles for spectrometry-based sensing have been widely investigated. However, sensitivity of conventional plasmonic spectrometry is not high enough for rapid and quantitative detection of molecules. Using LSPR in amperometric sensing is, therefore, considered to be a promising alternative, which may open new possibilities for rapid quantitative detection and fulfill portable sensing requirements by offering low fluid level detection and real-time feedback. However, progress in plasmonic amperometric sensing was slow because it is still challenging to fabricate ideal plasmonic platforms without suffering from powdered nanomaterials aggregation and performance degradation. In this work, a facile solution to these issues is developed using
periodically patterned
Au-TiO2 heterostructures for photoelectrochemical sensor. These rationally designed patterned nanostructures possess enhanced sensitivities for molecule detection, which are superior to other metal nanoparticle-based plasmonic sensing systems.
One-Pot Synthesis of Theranostic Nanocapsules with Lanthanide Doped Nanoparticles
Authors: Wang Miao , Zhang Yu , Ng Michael , Skripka Artiom , Cheng Ting , Li Xu , Bhakoo Kishore Kumar , Chang Alex Y. , Rosei Federico , Vetrone Fiorenzo
Published: May 2020

In this work, we have established a one-pot synthesis strategy to develop a new theranostic nanoplatform by simultaneously encapsulating Er3+, Yb3+ doped NaGdF4 upconverting nanoparticles (UCNPs) and photosensitizer zinc phthalocyanine (ZnPc) into polymeric micelle/silica nanocapsules. This approach consisted of interfacial templating condensation, using triblock copolymers, ethylene oxide)106(propylene oxide)70(ethylene oxide)106 (PEO-PPO-PEO), as the templating and protecting agent. The encapsulation followed a straightforward microemulsion mechanism in an aqueous environment of a near neutral pH. The surface hydrophobic nature of UCNPs is crucial for the success of encapsulation. To prevent the interaction between the hydrophobic OA ligands of UCNPs and the silanol groups of hydrated tetramethoxysilane (TMOS), we modified the previous procedure by tuning the addition sequence of TMOS. It allowed first to encapsulate UCNPs in PEO-PPO-PEO micelles, and then grow the silica shell within the micellar PPO core and PEO corona interface. The silica shell is incorporated for its chemical and mechanical stability, while the PEO corona confers additional steric stability to the nanocapsule. Using the modified strategy we successfully co-encapsulated UCNPs and ZnPc in one-pot, and minimized the distance between the two payloads to facilitate the energy transfer from UCNPs to ZnPc, as compared to conventional PS loading in the mesoporous silica coating. The integrated nanocapsule has an average hydrodynamic size of 85 nm with a low polydispersity index of 0.1, and demonstrates excellent colloidal stability, biocompatibility, as well as enhanced negative contrast for T2-weighted imaging and photodynamic therapy. The latter is obtained through indirect excitation of co-encapsulated ZnPc by UCNPs, resulting in singlet oxygen generation and in vitro eradication of BT474 breast cancer cells. Overall, the presented one-pot approach shined light on the co-encapsulation of OA capped inorganic UCNPs with hydrophobic photosensitizers, constituting an important step forward in the surface engineering of UCNPs, as well as upconversion based photodynamic therapy delivery systems.
(Invited) ZnCl2-Based Water-in-Salt Electrolytes in Zn Batteries
Authors: Ji Xiulei , Zhang Chong , Jiang Heng , Wu Xianyong , Hong Jessica , Xu Yunkai
Published: May 2020

A storage battery should be safe, ideally has the energy density and cycle life of Li-ion batteries, and can be manufactured at a similar cost as Lead-Acid batteries. The excellent performance and the low cost will result in a low levelized energy cost (LEC). The commercialization of such a battery technology will be disruptive to the entire energy industry. Such batteries will increase the adoption of renewables, microgrids, and home power, and enable a more reliable and resilient grid. A new electrolyte system is a pivot to transform the conventional primary Zn batteries into highly reversible secondary batteries. Our recent results demonstrate that ZnCl2 based aqueous electrolytes render plating and stripping of Zn metal anode highly reversible. Zn metal anode in such electrolytes exhibits a Coulombic efficiency of 99.8% at 1 mA cm-2, and does not grow any irregular morphology, including dendrites. Our new electrolytes take on the hydrogen evolution reaction—the showstopper—in Zn metal batteries by strengthening the O-H covalent bonds of water. Such a Zn anode delivers a long cycle life of 1500 cycles by coupling with a commercially available cathode. We have also explored the new electrolytes to address the cathode dissolution problem of Zn metal batteries by leveraging on the reversible anion storage that delivers very stable cycling performance. The research on such new electrolytes broadens the horizon of the electrochemical energy storage.
(Invited) Skin-Interfaced Self-Powered Wearable Sensors
Authors: Gao Wei
Published: May 2020

Electronic skin (e-skin) is expected to play a crucial role in the next generation of robotics and medical devices. However, existing e-skin-based sensing platforms primarily focus on monitoring physical parameters and rely on the power from the batteries or near field communication, which significantly hinders their broad use and sustainability toward continuous wireless sensing. Here I will introduce our recent works on flexible self-powered integrated electronic skin for multiplexed metabolic sensing in situ. These battery-free wearable sensors contain biosensors as well as highly efficient energy harvesters that utilize a unique integration of 0 dimensional to 3 dimensional nanomaterials to achieve remarkably high power intensity and long-term stability. The wearable devices could selectively monitor key metabolites and electrolytes during prolonged physical activities, and wirelessly transmit the data to the user interface. Such battery-free soft wearable systems with highly efficient energy harvesting from the human body hold great promise for robotics and personalized healthcare applications.
(Invited) Single-Strand Conducting Polymer Fiber-Based Wearable Sweat Sensors
Authors: Yoon Myung-Han
Published: May 2020

Despite the great potential of polymer microfibers in human-friendly wearable electronics, most previous polymeric electronics have been limited to thin-film-based devices due to practical difficulties in fabricating microfibrillar devices, as well as defining the active channel dimensions in a reproducible manner. Herein, we report on conducting polymer microfiber-based organic electrochemical transistors (OECTs) and their application in single-strand fiber-type wearable ion concentration sensors. We developed a simple wet-spinning process to form very conductive poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) microfibers using aqueous sulfuric acid solutions and carefully examined their electrical/electrochemical properties. In conjunction with fabricating substrate-free PEDOT:PSS microfiber-based OECT devices, the proposed novel characterization method demonstrated that the current variation ratio can be a reliable method for evaluating the device performance for sensing ion concentrations, regardless of the actual channel dimensions. Finally, we developed single-strand fiber-type skin-mountable OECTs by introducing a source-gate hybrid electrode and demonstrated that the resultant microfiber sensors can perform real-time repetitive measurements of the ion concentration in human sweat.
Sputtered Thermoelectric Nanoparticles for an Ultra-Thin, Flexible and Cuttable Self-Powered Temperature Sensor
Authors: Lin Zong-Hong , Khan Imran
Published: May 2020

Inadequate energy for the growing population has been a major concern in the recent years. Though efforts are being made to alleviate this problem, the crisis still exists. For this reason, the focus of the scientific community is directed towards self-powered technology. As technology is getting smart, smart sensors are also gaining attention. Human beings are getting more and more concerned about their health and opt for the best personalized health care devices. Body temperature is a vital sign which reflects the health condition and thermoregulation in human beings. For continuous monitoring of body temperature, devices which are compact, lightweight and self-powered is therefore desirable. So, we design a highly flexible, ultra-thin and conformable temperature sensor which just uses heat from the body as a power source and senses the body temperature precisely. The sensor works on thermoelectric effect and can detect any surface temperature from room temperature to 100 ˚C and also room temperature to 0 ˚C owing to its conformable and compact design and can be cut into desirable shapes and size. For a temperature gradient of 75 ˚C the sensor gives and output voltage of 0.4 mV and can even detect a human finger touch with an accurate body temperature. Such flexible and thin device can be used in day to day monitoring of human beings enabling it to be used as a wearable temperature sensor, hot or cold surface temperature measurement which may create injury if touched or as a biomedical device for the measurement of hyperthermia or even monitoring the health of pets.
Gas Identification Method Based on Transfer Function Ratios Toward Artificial Olfaction
Authors: Imamura Gaku
Published: May 2020

Olfaction is the only human sense that has not been realized as a practical sensor. To realize practical artificial olfaction, it is essential to establish a simple measurement protocol that people without expertise can follow. In this study, a novel data analysis method for odor identification is proposed. The key concept of the analysis method is transfer function ratios (TFRs), which are intrinsic to the combination of sensors and odors. Based on TFRs, one can identify odors without controlling or monitoring gas flow because TFRs are independent of gas flow and can be calculated only from sensing signals. To demonstrate the feasibility of the analysis method based on TFRs, odor identification through the free-hand measurement was performed; the odor of a sample was measured by manually moving a small sensor chip—membrane-type surface stress sensors (MSS)—near the sample (Fig. 1a). TFRs were calculated from the measurement data obtained through the free-hand measurements on three spices: rosemary, garlic and red chili pepper. Principal component analysis (PCA) was performed on the dataset of the TFRs, resulting in the formation of three clusters corresponding to the spices. Machine learning models were developed from the dataset of TFRs. By using random forest as a classifier, the odors can be identified with an accuracy of 0.89±0.04. These results indicate that the data analysis method based on TFRs provides the easy measurement protocol for odor identification, leading to the realization of practical application of artificial olfaction.

Figure 1
Developing a Deep Learning Sound Classification System for a Smart Farming
Authors: Kudin Oleksii , Kryvokhata Anastasiia , Gorbenko Vitaliy Ivanovich
Published: May 2020

The Internet of Things (IoT) and Machine Learning (ML) are a promising technologies for automation in the different domains e.g. Smart Farming. Such systems could be used for determining noise emission, animal detection and classification, monitoring states of bees in beehive and etc. As rule the characteristics of that systems are some controversial: compactness (deploying on the single-board computers) and real time classification and prediction. Therefore, the software for IoT and ML applications should be sufficiently efficient and not demanding on large computing resources. This work are focused on machine hearing system allows to classify natural sounds in the Smart Farming software application.

The original acoustic signal is converted to the frames of a certain length. Receiving a compact representation of the acoustic characteristics of a signal is the aim of the feature extraction stage. This stage exploits special coefficients such as Zero-crossing rate, Spectrum shape, Short-Time Fourier Transform and Mel-frequency cepstral coefficients. Audio classification traditionally involves such machine learning methods as K-means, support vector machine (SVM), decision trees etc. Deep neural networks can be used on both raw acoustic signal and features extracted from it. The accuracy estimation stage deploys quality assessment methods.

The data preprocessing stage includes calculating of mel frequency cepstral coefficient (MFCC) for the giving sound files. This approach allows to unify and simplify the sound files presentation in the memory. Further MFCC arrays are feeding to the convolutional neural net. It is important at this stage to configure the network optimally for the most compact storage. This is due to the need to use platforms such as Raspberry Pi to deploying neural network.

For neural network software implementation Python library Keras is used. For data preprocessing Python library Librosa is used. The hyperparameters of the neural network have been defined in computational experiments and the optimal combination is two Conv2D layers and three Dense layers.

The accuracy of model predictions for each class has been examined by using a confusion matrix and the satisfactory classification accuracy has been defined.

It has been established the convolutional neural network ensemble built to solve the problem of acoustic data classification is quite effective. The accuracy of the model on the test data is 95%. It should be noted that the neural network structure with only two packets of convolution-activation-sub-sampling layers was sufficient to solve this problem. The system can be used in Smart Farming applications to filter out unnecessary sounds.
A Label Free Sensing Approach for the Detection of Patulin in Food Samples
Authors: Khan Reem , Sherazi Syed Tauqir A. , Hayat Akhtar , Andreescu Silvana
Published: May 2020

Mycotoxins are small agro-based food contaminants that pose serious health threats to humans and animals. Patulin (PAT) is a low molecular weight mycotoxin produced by various fungal species and is commonly present in fruit- and vegetable-based products. Available detection methods for patulin detection suffered with some drawbacks such as high running cost and complex instrumentation. In the present work, an aptasensing platform was developed for the detection patulin (PAT) using a label-free approach. The detection was mainly based on a specific interaction of an aptamer immobilized on carbon-based electrode. A long linear spacer of carboxy-amine polyethylene glycol chain (PEG) was chemically grafted on screen-printed carbon electrodes (SPCEs) via diazonium salt in the aptasensor design. The NH2-modified aptamer was then attached covalently to carboxylic acid groups of previously immobilized bifunctional PEG to build a diblock macromolecule. The immobilized diblocked molecules resulted in the formation of long tunnels on a carbon interface, while the aptamer was assumed as the gate of these tunnels. Upon target analyte binding, the gates were assumed to be closed due to conformational changes in the structure of the aptamer, increasing the resistance to the charge transfer. This increase in resistance was measured by electrochemical impedance spectroscopy. Encouragingly, a good linear range between 1 and 25 ng was obtained. The limit of detection and limit of quantification was 2.8 ng L−1 and 4.0 ng L−1, respectively. Selectivity of the aptasensor was confirmed with mycotoxins commonly occurring in food. The developed apta-assay was also applied to a real sample, i.e., fresh apple juice spiked with PAT, and toxin recovery up to 99% was observed. The results obtained validated the suitability and selectivity of the developed apta-assay for the identification and quantification of PAT in real food.
1-Amino 2-Naphthol Modified Solvent Filled Carbon Nanotubes for Enhanced Electrochemical Sensing of Bioanalytes
Authors: Gurusamy Tamilselvi , Ramanujam Kothandaraman
Published: May 2020

Our research interest is mainly on developing cost-effective electrochemical sensors for bioanalytes sensing. For example, bioanlytes such as ascorbic acid, dopamine, and uric acid present together in human body poses challenge for selective sensing of one over other. As these molecules play a vital role in controlling the body’s metabolism, it is paramount to develop a sensor tool with high sensitivity towards these bioanlytes for diagnosing diseases, including AIDS, Parkinsonism, etc. Development of fast and reliable methods for sensing these biomolecules is of considerable importance in offering rapid diagnosis.1–3 In the present experimental work, it is shown for the first time that liquid-filled multi-walled carbon nanotubes (MWCNTs) exhibit remarkably enhanced characteristics for sensor applications, the detection threshold being lowered by as much as an order of magnitude, while detection sensitivity is doubled for a number of molecules including ascorbic acid, dopamine, and uric acid. 1H NMR relaxometry at a moderately low field, i.e., 14.6 MHz (0.34 T), confirms that the improved sensor characteristics are correlated with the filling of MWCNTs with solvents such as acetonitrile, dimethyl sulfoxide, etc. The molecular motions are slowed down when solvent molecules fill MWCNTs, thus increasing motional correlation times, and hence, longitudinal relaxation rate increases under extreme narrowing conditions. The filling of MWCNTs appears to relate to solvent-CNT interactions that are in line with the principle of hard and soft acids and bases, and also correlates with solvent dipole moments.4 We have further enhanced the detection limit and selectivity towards ascorbic acid by modifying the MWCNTs surface with amino naphthol.

References

1. K. Iriyama, M. Yoshiura, T. Iwamoto, and Y. Ozaki, Anal. Biochem., 141, 238–243 (1984).

2. L. Jothi, S. Neogi, S. kumar Jaganathan, and G. Nageswaran, Biosens. Bioelectron., 105, 236–242 (2018).

3. M. Jahan, Z. Liu, and K. P. Loh, Adv. Funct. Mater., 23, 5363–5372 (2013).

4. T. Gurusamy, A. Banerjee, N. Chandrakumar, and K. Ramanujam, J. Electrochem. Soc., 166, B1186–B1195 (2019).

Figure 1
Electrochemistry of Neuronal Tau Protein
Authors: Martic Sanela
Published: May 2020

Tau protein is critical for normal brain function but then it undergoes modification it is prone to aggregation into cytotoxic species which lead to diseases [1]. Hence, tau is a druggable target, as well as the biomarker of neurodegenerative disease. We reported on the detection of tau modification, specifically phosphorylation, and its inhibition by antibodies by using electrochemical impedance spectroscopy (EIS) [2]. In addition, the EIS was utilized to monitor binding interactions between large molecules, such as heparin, ferritin and transferrin to tau protein [3]. Tau protein biomarker detection was also achieved by using the same method. Currently, we are exploring tau protein self-assembly towards developing electrochemical assay for detection of early onset of tau pathology. Electrochemical assay for tau protein would allow for early detection and diagnosis of diseases, as well as drug inhibitor screening against neurodegenerations.

References:

1. Lasagna-Reeves, C.A., Castillo-Carranza, D.L., Sengupta, U., Sarmiento, J., Troncoso,J., Jackson, G. R., Kayed, R. Identification of oligomers at early stages of tau aggregation in Alzheimer’s disease. FASEB J., 2011, 26, 1946-1959.

2. Esteves, J.O.V., Martic-Milne, S. Electrochemical detection of anti-tau antibodies binding to tau protein and inhibition of GSK-3-β-catalyzed phosphorylation, Anal. Biochem. 2016, 496, 55-62.

3. Jahshan, A., Esteves, J.O.V., Martic-Milne, S. Evaluation of ferritin and transferrin binding to tau protein, J. Inorg. Biochem. 2016, 162, 127-134.
High Sensitivity Sensor for C-Reactive Protein Detections
Authors: Kutova Oksana , Dusheiko Mykhailo , Skryshevsky Valeriy A , Xu Guobao
Published: May 2020

Among the various type of sensor strucrures, cyclic voltammetry (CV), chronoamperometry, impedance spectroscopy, and various methods based on ion sensitive field effect transistors (ISFET) in combination with modern low-dimensional systems are very popular. ISFET sensors show a high signal-to-noise ratio, high measurement speed, compactness and portability. This work is dedicated to development sensor to detect C-reactive protein (CRP) based on ISFET. CRP - inflammatory protein that dramatically increases during the inflammatoryduring inflammatory.

For the first time, a multilayer structure for the C-reactive protein detection was proposed, using a sensor based on the CeO2 ISFET as a sudgate dielectric and n-type field-effect transistor as a platform. For this sensor, the limit of detection at 0.1 mg/L and the sensitivity at 290 mV/(mg/L) were established. For this analysis should be only 20 μl of the reagent and about 1 min of time was needed. The developed sensor showed good stability in work for 30 days. Another interesting feature of this sensor was observed. It can work not just with standard test kits, but also in real human blood serum. The response of the sensor on real blood serum samples was just 18% less than the results from the calibrations antigen CRP concentrations for the standard test kit at the enzyme-linked immunosorbent assay.

To increase the sensitivity the additional buffer layer - melanin was used. Such layer increased the sensor sensitivity by almost 61%.

To get good and stable results the experiment was carried out at the stable ambient conditions: temperature ~ 20°C and at the same level of illumination (put sensor in dark box).

The performance of the biosensor is influenced not just by the antibody concentration and also by the incubation time of CRP. During incubation, the antigen antigen-antibody complex is formed. It takes some time to get this complex on the sensor working surface. With an increasing incubation time, the current response decreases and stabilizes after ~0.5 hourds. To obtain the optimal current response the incubations time of 30 min was found.

In conclusion, such results of CRP sensor based on ISFET with CeO2 as gate dielectric are the basis for using this sensor in real clinical trials, particularly for screening trials.

Figure 1
(Invited) Disposable Polyurethane Nanospiked Gold Electrode-Based Label-Free Electrochemical Immunosensor for Clostridium Difficile
Authors: Cui Feiyun , Zhou Zhiru , Feng Hanping , Zhou H. Susan
Published: May 2020

A polyurethane (PU) nanospiked gold electrode-based label-free electrochemical immunosensor for Clostridium difficile (C. difficile) toxin B detection was developed. Different from nanomaterials-modified electrode, the PU nanospiked gold electrode was fricated by soft lithography directly. The morphology of the nanospiked electrode was characterized by scanning electron microscope (SEM), and its good electrochemical performance was demonstrated by cyclic voltammetry (CV) as well as differential pulse voltammetry (DPV). Then, the PU nanospiked gold electrode-based immunosensor was developed by fixing anti-toxin B single domain antibody on the electrode surface as the receptor. DPV was used as a detection technology for C. difficile toxin B detection. It revealed that the immunosensor has good specificity, repeatability, and stability. Even in a label-free style, the limit of detection for toxin B was 0.5 pg/mL. With the increase of the concentration of toxin B from 1 pg/mL to 130 pg/mL, a linear relationship was observed between the peak current and toxin concentration. Compared with flat PU electrode-based immunosensor, the detection signal of PU nanospiked gold electrode-based immunosensor was amplified about 6 times. Benefitted from its low cost and simple processing, the PU nanospiked gold electrode-based immunosensor can be used a disposable electrochemical sensor for toxin B rapid detection.
(Invited) Barcode-Based Biorecognition for Electrochemical and Photoelectrochemical Biosensing
Authors: Soleymani Leyla , Pandey Richa , Traynor Sarah , Victorious Amanda Pansy , Saha Sudip
Published: May 2020

Biosensors are devices that combine biorecognition with signal transduction to analyze biologically-relevant targets. In order for these devices to be used in disease management, clinical decision making, and health monitoring, they must deliver sufficient sensitivity, specificity, and speed at the point-of-care and rely on minimal sample processing. This work is focused on developing integrated biorecognition and signal transduction strategies for enhancing the performance metrics of biosensors.

Barcode-based biorecognition systems translate analyte capture to the release of specific signal transducing barcodes. We have focused on developing barcode-based systems that are compatible with photoelectrochemical and electrochemical readout for targeting proteins and nucleic acids. These systems translate molecular recognition elements using functional nucleic acids and antibody-DNA complexes for releasing an electroactive or a photoelectrochemical barcode. We have combined these barcode-based systems with nanostructured electrochemical transducers for increased signal-to-noise-ratio and sensitivity.

By combining barcode-based biorecognition with electrochemical readout, we have developed handheld biosensors for clinical analysis of urinary tract infections. We have also used these strategies for detecting prostate cancer biomarkers. Integration of barcode-based biorecognition with photoelectrochemical readout presents a new modality for biosensing and opens the route for ultrasensitive and programmable biosensing.
Ultrasensitive 3D Printed Immunoarrays for Protein Detection Down to Single Cell Levels
Authors: Rusling James F. , Sharafeldin Mohamed , Chen Tianqi , Jones Abby L , DhanapalaMudiyanselage Lasangi
Published: May 2020

Accurate, sensitive measurements of proteins are crucial for modern biomedical research, with applications in basic research, medical diagnostics, therapy guidance, and drug development. Fast, selective, low cost detection of multiple proteins is important for public health and a key component of future personalized medicine. There are >50,000 gene product proteins (omitting post-translational modifications and IgGs) in human plasma, and large subsets in serum, urine, and saliva. However, techniques such as LC-MS/MS, immunoassays and protein counting can reliably detect <2000 of these proteins and are quite expensive. This paper addresses the challenge to develop low cost, automated 3D-printed immunoarrays for liquid protein samples and cells with LODs <0.1 fg/mL. We have developed prototype multiplexed microfluidic immunoarrays with sensitivity better than protein counting applicable to plasma, serum, saliva, urine, cell lysates and cell cultures. Protein detection at the single cell level was also achieved.

Unique detection features including nanostructured sensing, array design, and protocol optimization provide large decreases in LODs and greatly enhanced sensitivities. Our prototypes are based on chemiluminescence (CL) and amperometric detection. Our CL array achieved LODs of 0.1 fg/mL for membrane protein DSG3, as well as VEGF-C and VEGF-D in conditioned media of cell cultures. This LOD is 0.8 zeptomolar, or ~100 molecules of DSG3 in 90 mL and results from 30 trillion capture antibodies (Ab1) in array detection cylinders using an ultrabright femto-luminol CL reagent activated by H2O2 and poly-(horseradish peroxidase) (poly-HRP, 400 HRPs/molecule). Femto-luminol combined with poly-HRP provides very high CL signal amplification and S/N using the 400 HPR polymer.Proteins are also efficiently captured in detection cylinders with 30 trillion antibodies, combined with the ultrabright CL reagent and rigorous protocol optimization to prove unprecedented LODs. Microprocessor automation can achieve fast multiplexed assays with these immunoarrays at <$0.50/protein. We are also exploring ultra-high sensitivity amperometric detection in these systems with similar sensitivity enhancement principles.