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C-Reaction protein (CRP) is a marker of nonspecific immunity for vital signs and wound assessment, and it can be used to diagnose infections in clinical medicine. However, measuring CRP level currently requires hospital-based instruments, high-cost reagents, and a complex process, all of which have limited its full capabilities for self-detection, a growing trend in modern medicine. In this study, we developed a novel smartphone-based device using advanced methods of magnetoelastic immunosensing to mitigate these limitations. We combined a system-on-chip (SoC) hardware architecture with smartphone apps to realize the sampling of resonance frequency shift on magnetoelastic chips, which can determine the ultra-sensitivity to mass change caused by the binding of anti-CRP antibody and CRP. Through detecting a multi-group of samples, we found that the resonance frequency shift was linearly proportional to the CRP concentration in the range from 0.1 to 100 μg mL−1, with a sensitivity of 12.90 Hz μg−1 mL−1 and a detection limit of 2.349 × 10−4 μg mL−1. Meanwhile, compared with the large-scale instrument used in clinical settings, the performance of our device was stable and significantly more portable, rapid and cost-effective, offering excellent potential for modern home-based diagnosis. [ABSTRACT FROM AUTHOR]

Purpose: In this article, we develop a dynamic Bayesian network (DBN) model to measure 3D visual fatigue. As far as our information goes, this is the first adaptation of a DBN structure‐based probabilistic framework for inferring the 3D viewer's state of visual fatigue. Methods: Our measurement focuses on the interdependencies between each factor and the phenomena of visual fatigue in stereoscopy. Specifically, the implementation of DBN with using multiple features (e.g. contextual, contactless and contact physiological features) and dynamic factor provides a systematic scheme to evaluate 3D visual fatigue. Results: In contrast to measurement results between the mean opinion score (MOS) and Bayesian network model (with static Bayesian network and DBN), the visual fatigue in stereoscopy at time slice t is influenced by a dynamic factor (time slice t−1). In the presence of dynamic factors (time slice t−1), our proposed measuring scheme based on DBN is more comprehensive. Conclusion: (i) We cover more features for inferring the visual fatigue, more reliably and accurately; (ii) at different time slices, the dynamic factor features are significant for inferring the visual fatigue state of stereoscopy. [ABSTRACT FROM AUTHOR]

• This paper proposed a new cost-effective smartphone-based ankle-brachial index (ABI) device. • We presented a simple, cuffless and non-invasive ABI instruments. • One set of real test data from 36 volunteers are used to contrast between ours and a commercial instrument, accuracy achieved more than 91%. Detectors of ankle-brachial index (ABI) are commonly used in cardiovascular patients who have high-risk levels of arteriosclerosis. Increased evidences suggest that patients with arteriosclerosis possess many risks of geriatric and chronic diseases. Meanwhile, new chronic treatments trend from the hospitals toward family and community health centers, but for arteriosclerosis cases have delivered benefits far below instrument costs. Compared to traditional devices based on cuff pressure, cuffless and non-invasive measures have wider application potential in home health care, especially in the case of physically-restricted or severely symptomatic patients. In this study, we developed a simple smartphone-based device for non-invasive ABI monitoring, which consists of four wireless cuffless limbs blood sensors. By identifying and tracking blood flow waveform, a multiparameter fusion (MPF) algorithm is used to estimate blood pressure and generate ABI value. An ARM-based chip STM32 has been adopted as the microcontroller. The ABI calculating program is embedded in C ++ and executed by the processor. After generating data, ABI information can be delivered to the smartphone by using Bluetooth. Relying on mobile apps to visualize the data and display on the screen, doctors can monitor cardiovascular patients in real time and analyze the risk levels of arteriosclerosis online. In this paper, the detection conducted by the classical Doppler equipment and prototype were recorded respectively. A statistical evaluation of the verification results obtained from 29 patients and 7 sub-health volunteers is given, which shows that our device can achieve 91.80% and 93.84% accuracy for patients and sub-health volunteers, respectively. In addition, the prototype can be performed stably for a continuous long time monitoring. According to our studies, the accuracy of our device is sufficient for home medical and chronic disease monitoring within a certain time interval. The smartphone-based ABI device has several apparent advantages over traditional devices, such as portability, cost-effectiveness and energy-efficiency. [ABSTRACT FROM AUTHOR]

In this study, a novel paper biosensor based on Fe3O4@SiO2–NH2 magnetic polymer microspheres and multi walled carbon nanotubes (MWCNTs) for rapid detection of pseudorabies virus (PRV) was first developed. Fe3O4@SiO2–NH2 were functionalized with PRV antibody and doped in cellulose nitrate paper to fabricate the magnetic paper biosensor with good magnetic response and biocompatibility. Using MWCNTs to build conductive network of sensors, PRV antigen binds specifically to the immunomagnetic microspheres on the sensor, and the resulting immune complex changes the magnetic domain structure of the sensor and the structural gap of MWCNTs, causing the magnetic property and impedance change. TEM and EDS characterization proved that the biosensor was successfully doped with Fe3O4@SiO2–NH2 and effectively recognized PRV. Under optimized conditions, the impedance variation was found to be linearly related to the logarithm value of PRV concentrations in the range of 10–1 mg ml−1, with the detection limit of 10 ng ml−1. This paper biosensor demonstrated advantages of portability, high sensitivity and specificity, providing a valuable method for early control of PRV. [ABSTRACT FROM AUTHOR]

The retinal vessels in the human body are the only ones that can be observed directly by non-invasive imaging techniques. Retinal vessel morphology and structure are the important objects of concern for physicians in the early diagnosis and treatment of related diseases. The classification of retinal vessels has important guiding significance in the basic stage of diagnostic treatment. This paper proposes a novel method based on generative adversarial networks with improved U-Net, which can achieve synchronous automatic segmentation and classification of blood vessels by an end-to-end network. The proposed method avoids the dependency of the segmentation results in the multiple classification tasks. Moreover, the proposed method builds on an accurate classification of arteries and veins while also classifying arteriovenous crossings. The validity of the proposed method is evaluated on the RITE dataset: the accuracy of image comprehensive classification reaches 96.87%. The sensitivity and specificity of arteriovenous classification reach 91.78% and 97.25%. The results verify the effectiveness of the proposed method and show the competitive classification performance. [ABSTRACT FROM AUTHOR]

The wide application prospects of flexible strain sensors and pressure sensors in robotic perception have led to an urgent demand for the high‐precision customized manufacturing and flexible integration of such devices. Herein, a 3D‐printed wearable strain and tactile sensing array is developed for robotic perception by integrating a flexible strain sensor and a pressure sensor with porous structures. The flexible strain sensor has a wide linear measurement range of 67.5% with a sensitivity of 2.64. Meanwhile, the flexible pressure sensor has a continuous pressure‐monitoring ability in the range of 0–1 N, and it is particularly sensitive to small pressures within 0.2 N. Both the sensors provide a stable output for the seamless sensing of different stimuli, and devices from the same batch provide highly consistent responses. By fully exploiting the flexibility of digital light‐processing 3D printing, the sensing array is customized for a robotic hand to realize the grip and finger bending perceptions of the manipulator. [ABSTRACT FROM AUTHOR]

The composite of gold and PDMS hold remarkable potential for surface stress-based biosensor applicaitons. However, the gold and PDMS in composite suffers from poor compatibility with each other and suppresses the performance of the biosensor. Here, we conduct two-step synthesis of the composite of gold and PDMS by in-situ reduction and glucose reduction of HAuCl 4. The composite shows stable conductive gold nanoparticle network (SC-AuNW). In in-situ reduction, Au-seeds are embedded in PDMS surface. Furthermore, AuNPs are also generated inside the PDMS and enhance conductivity. The SC-AuNW plays a crucial role in tunneling conductivity of composite film and exhibits an excellent sensitivity to surface stress. We construct SC-AuNW-PDMS biosensors based on surface stress for glucose detection with a detection limit of 0.021 mM, high repeatability and specificity. Our research can promote the application of flexible conductive films in biosensors for disease diagnosis. • The PDMS film with stable conductive gold network on surface was synthesized. • The film was sensitive to surface stress due to its tunneling conductivity. • The film with GOx-modified interface can specifically detect the glucose. [ABSTRACT FROM AUTHOR]

• The intrinsic magnetic properties can be modulated by geometrical configuration. • The spin degeneracy semiconducting ground state can be lifted by electric field. • The half-metallicity can be induced at critical electric field strength. It has been known for a long time that graphene flakes of certain geometries can develop spontaneous spin polarization. Here, it is studied what happens when two triangular graphene nanoflakes, possibly different sizes, are placed in close proximity with AB (Bernal) stacking. The results of first-principles calculations show that the magnetic ground state of the bilayer system depends on the different sizes of the two nanoflakes, and spin-related energy gap can be controlled with external electric fields. Under certain circumstances, the system even can be tuned into half-metallic nature, which might potentially be exploited in future spintronics applications. [ABSTRACT FROM AUTHOR]

Uniform crystalline Cu 2 O truncated octahedra constructed by 8 hexagonal {1 1 1} surfaces and 6 square {1 0 0} surfaces were quickly synthesized in high yield with glucose served as an environmental-friendly reducing reagent, and no template or surfactant was employed during the synthetic procedure. With reaction time prolonging, the {1 0 0} surfaces were selectively etched with a hole on each facet, and the hole would become bigger to form surface pits finally. The X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) characterizations indicated that these Cu 2 O truncated octahedral possessed cubic phase with very high phase purity. This simple one-pot synthetic route could provide a good starting point for the research of shape-dependent catalytic properties of other materials. [ABSTRACT FROM AUTHOR]

A simple hydrothermal method has been developed to synthesize Cu 2 Se film on copper foil with the assistance of cetyltrimethylammonium bromide (CTAB) as a surfactant. The Cu 2 Se film was constructed by novel nanowire networks with length up to 50 µm. The obtained product was characterized by XRD, SEM, HRTEM, Raman, and XPS techniques, revealing that Cu 2 Se nanowire possessed single-crystal structures. The shape of Cu 2 Se film changed from nanowire networks to perfect microflowers as the amount of CTAB increased. Such Cu 2 Se film may have great potential applications in biomedical engineering, sensors, and catalysis. [ABSTRACT FROM AUTHOR]

The stress-electric coupling based on receptor functionalization provides a new paradigm for biosensor development. However, it is difficult to avoid the gravity factor of the sensitive element since it can suppress biosensor sensitivity. Herein, a magnetic-sensitization sensing system based on multi-physical field coupling of stress, magnetism, and electricity is proposed to improve the sensitivity of surface stress biosensor. The gravitational interference of sensitive film is eliminated by the magnetostriction of TbDyFe under a magnetic field, amplifying the surface stress-induced film deformation. The urine protein and sugar detections associated with kidney disease serve as a proof of concept revealing the improved sensitivity. The calculated limits of detection (LODs) of urine protein and sugar are 0.21 ng/mL and 0.45 nM, respectively. The LODs are significantly lower than those of traditional surface stress biosensors without magnetic coupling, showing consistency with previous simulation and performance analysis. Furthermore, the urine protein and sugar in clinical samples are accurately detected, showing good practicability of the prepared biosensor. All these results indicate that magneto-stress-electric coupling in magnetostrictive effect contributes to the enhanced performance of surface stress biosensor and provides a platform for highly sensitive detection of clinical biomarkers. • Magnetic sensitization and multi-field coupling improve the biosensor sensitivity. • The biosensor realized high-performance detection of biomolecules. • The urine protein and sugar in clinical samples are accurately detected. [ABSTRACT FROM AUTHOR]

We demonstrate a self-powered wireless Morse code transmission method via a solid-liquid-solid TENG composed of a PTFE sheet, modified graphite electrodes, and a water tank. PTFE induces mechanical energy generated by motion to be extracted as electrical energy at the remote end, which provides the basis for wireless energy and information transmission. This approach frees the constraints of cables and produces intuitive signals that are easy to translate. [Display omitted] • The water-based TENG can realize mechanical-electrical energy conversion via solid-liquid interfacial contact/separation. • The mechanical energy generated by the movement of PTFE can be extracted as electrical energy from the remote electrode. • The wireless self-powered communication was demonstrated to transmit Morse code messages along water. Wireless communication has affected all aspects of our lives. However, most wireless communication devices require an external power supply, which undoubtedly hinders the development of numerous sensors. Triboelectric nanogenerator (TENG), a self-powered technology, has become an even more attractive solution to the energy problem of sensors. Herein, a novel solid-liquid-solid TENG configuration consisting of a polytetrafluoroethylene (PTFE) sheet, a water sink, and a graphite electrode is proposed. It is worth noting that it can transmit mechanical energy by employing only the electric double layer (EDL) formed at the interface between water and the graphite electrode. PTFE induces mechanical energy generated by motion to be extracted as electrical energy at the remote end, which provides the basis for wireless energy and information transmission. More impressively, a self-powered application based on the designed TENG was successfully demonstrated to transmit Morse code messages through the water as a medium. This approach frees the constraints of cables and produces intuitive signals that are easy to translate. This study paves the way for a promising strategy in the development of wireless energy transmission and battery-less communication. [ABSTRACT FROM AUTHOR]

For the first time, a novel NiFe2O4/paper-based magnetoelastic (ME) biosensor was developed for rapid, sensitive, and portable detection of human serum albumin (HSA). Due to the uniquely magnetoelastic effect of NiFe2O4 nanoparticles and the excellent mechanical properties of the paper, the paper-based ME biosensor transforms the surface stress signal induced by the specific binding of HSA and antibody modified on the paper into the electromagnetic signal. The accumulated binding complex generates a compressive stress on the biosensor surface, resulting in a decrease in the biosensor's static magnetic permeability, which correlates to the HSA concentrations. To improve the sensitivity of the biosensor, the concentration of NiFe2O4 nanofluid and the impregnated numbers of the NiFe2O4 nanofluid-impregnated papers were optimized. The experimental results demonstrated that the biosensor exhibited a linear response to HSA concentrations ranging from 10 μg∙mL−1 to 200 μg∙mL−1, with a detection limit of 0.43 μg∙mL−1, which is significantly lower than the minimal diagnosis limit of microalbuminuria. The NiFe2O4/paper-based ME biosensor is easy to fabricate, and allows the rapid, highly-sensitive, and selective detection of HSA, providing a valuable analytical device for early monitoring and clinical diagnosis of microalbuminuria and nephropathy. This study shows the successful integration of the paper-based biosensor and the ME sensing analytical method will be a highly-sensitive, easy-to-use, disposable, and portable alternative for point-of-care monitoring. [ABSTRACT FROM AUTHOR]

• An ME DNA-biosensor was developed to detect a common mutated DNA causing β-thalassaemia. • sDNA-AuNPs serve as the signal amplifier. • The sandwich-type structure enables label-free detection. • A low detection limit of 0.571 pM and high sensitivity of 72.7 Hz/nM were obtained. • The DNA-biosensor exhibits excellent sensitivity, selectivity and stability. β-Thalassaemia is an inherited blood disorder with serious complications. Combining the unique advantages of DNA and magnetoelastic (ME) materials, an ME DNA-biosensor was proposed that can wirelessly detect a target DNA sequence (tDNA) that is a 4-bp deletion in codon 41/42 (-TTCT) in the β-globin gene causing β-thalassaemia. The thiolated capture probe (CP) was covalently immobilized on the surface of the gold-plated ME chip and then hybridized to tDNA, and AuNPs modified with thiolated signal probe DNA (sDNA-AuNPs) serve as the signal amplifier and the direct signal indicator, enabling label-free detection. The specific hybridization process of sDNA-AuNPs to tDNA increased the surface load mass and decreased the resonance frequency of the DNA-biosensor. The resonance frequency shift of the DNA-biosensor was linear to the logarithmic concentration of tDNA in the range of 1.0 × 10−8 M to 1.0 × 10−12 M, with a detection limit (LOD) of 0.571 pM (S/N = 3) and sensitivity of 72.7 Hz/nM. The ME DNA-biosensor exhibits excellent selectivity and stability for the detection of the mutated DNA (4-bp deletion in codon 41/42) causing β-thalassaemia, suggesting this is a promising method for the clinical diagnosis of β-thalassaemia. [ABSTRACT FROM AUTHOR]

Abnormal protein concentration levels in human body fluids, such as urine, serum etc., are considered to associate with disease states, providing essential information for the pre-clinical diagnosis. This paper presents a wireless immunoglobulin-coated magnetoelastic (ME) biosensor for fast, cost-effective detections of human serum albumin (HSA) with small sample volumes at a microliter scale. This is the first portable resonant sensor based on magnetostrictive effect that can monitor different molecular states of HSA. Anti-HSA Immunoglobulin G (IgG) was immobilized on the surface of the ME sensor to selectively capture HSA. The rapid conjugation between the antibody and antigen changed the sensor surface states and thus induced resonance frequency shifts (RFS), which were monitored in real time for the qualitative and quantitative analysis of HSA. This paper brings forward a System on Chip (SoC)-based system architecture to realize the function of RFS sampling. The performance of the portable device was validated to be comparable to that of the Vector Network Analyzer (VNA) AV3620 using different concentrations of HSA solution. The RFS were linearly proportional to the HSA concentrations in the range from 0.1 to 100 μg/mL with a linearity up to 0.998, a sensitivity of 8.70 Hz/μg.mL-1 and a detection limit of 0.039 μg/mL, indicating good feasibility of this method. Meanwhile, the response of this portable ME biosensor was quick and specific to HSA targets. This ME biosensor shows high potential to be used in diagnosing abnormal HSA. • This paper proposed a new portable resonant sensor with high-specificity based on magnetostrictive effect. • We presented a magnetoelastic (ME) biosensor for fast, cost-effective and tiny detections of human serum albumin (HSA). • In this paper, HSA can be detected with a sensitivity of 8.70 Hz/μg.mL-1 and detection limit of 0.039 μg/ml. [ABSTRACT FROM AUTHOR]

Flexible electronics devices with tactile perception can sense the mechanical property data of the environment and the human body, and they present a huge potential in the human health system. In particular, the introduction of ultra-flexible and self-powered characteristics to tactile sensors can effectively reduce the problems caused by rigid batteries. Herein, we report a triboelectric nanogenerator (TENG), mainly consisting of an ultra-flexible polydimethylsiloxane (PDMS) film with micro-pyramid-structure and sputtered aluminum electrodes, which achieves highly conformal contact with skin and the self-powered detection of human body motions. The flexible polyethylene terephthalate (PET) film was selected as spacer layer, which made the sensor work in the contact-separation mode and endowed the perfect coupling of triboelectrification and electrostatic induction. Moreover, the controllable and uniform micro-structure PDMS film was fabricated by using the micro-electro-mechanical system (MEMS) manufacturing process, bringing a good sensitivity and high output performance to the device. The developed TENG can directly convert mechanical energy into electric energy and light up 110 green Light-Emitting Diodes (LEDs). Furthermore, the TENG-based sensor displays good sensitivity (2.54 V/kPa), excellent linearity (R2 = 0.99522) and good stability (over 30,000 cycles). By virtue of the compact size, great electrical properties, and great mechanical properties, the developed sensor can be conformally attached to human skin to monitor joint movements, presenting a promising application in wearable tactile devices. We believe that the ultra-flexible and self-powered tactile TENG-based sensor could have tremendous application in wearable electrons. [ABSTRACT FROM AUTHOR]