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The calcium (Ca2+) permeable transient receptor potential vanilloid 4 (TRPV4) cation channel is expressed in neutrophils and contributes to myocardial ischemia/reperfusion (I/R) injury. Here we tested the hypotheses that TRPV4 promotes neutrophil activation and subsequently aggregates myocardial I/R injury. TRPV4 protein was confirmed in neutrophils and its function was assessed by the current and intracellular Ca2+ concentration elevations evoked by TRPV4 agonists. Furthermore, TRPV4 agonists dose-repandly promoted migration toward fMLP, reactive oxygen species (ROS) production, and myeloperoxidase (MPO) release, which were prevented by pretreatment with a selective TRPV4 antagonist, in neutrophils from TRPV4 knock-out (KO) mice, Ca2+-free medium, or BAPTA-AM + Ca2+-free medium. Blockade of TRPV4 also inhibited the effects of commonly used neutrophil activators N-formyl-l-methionyl-leucyl-l-phenylalanine (fMLP) and Phorbol 12-myristate 13-acetate (PMA). Mechanically, TRPV4 regulated neutrophil activation, particularly ROS production, by affecting PKCα, P38, and AKT via Ca2+ signaling. In addition, isolated hearts infused with neutrophils from wild-type (WT) mice showed additional myocardial I/R injuries, but not those infused with TRPV4 KO. Our study reveals that TRPV4-mediated neutrophil activation enhances myocardial I/R injury, and it might be a novel therapeutic target for myocardial I/R injury and other neutrophil-mediated inflammatory diseases.

AimsCD4+ T cells are the major drivers of cardiac-specific autoimmunity in myocarditis, specifically Th1, Treg, and most significant Th17 cells. But the molecular mechanisms of their activation remain unclear. We aimed to elucidate the regulatory role of phosphoglycerate kinase 1 (PGK1) in CD4+ T cells and experimental autoimmune myocarditis (EAM).Methods and resultsEAM was induced in BALB/c mice by subcutaneous injections with alpha myosin heavy chain peptide emulsified in complete Freund’s adjuvant. Single-cell sequencing analysis found that glycolysis and PGK1 expression were elevated in cardiac CD4+ T and Th17 cells from myocarditis mice. Mice treated with PGK1 inhibitor NG52 showed less cardiac inflammation and fibrosis and better contractile function, as well as reduced cardiac infiltrating Th17 and Th1 cells and increased proportion of Treg. NG52 suppressed CD4+ T cell activation and differentiation of mice and myocarditis patients in vitro. Mechanistically, inhibition of PGK1 suppressed glycolytic activity and decreased pyruvate dehydrogenase kinase 1 (PDHK1) phosphorylation, thereby increasing reactive oxygen species (ROS) production in mitochondria and thus preventing Th17 cell differentiation.ConclusionPGK1 may act as a key metabolic regulator of CD4+ T cell differentiation and regulates Th17 cell differentiation by regulating glycolysis and the PDHK1-ROS axis. Targeting PGK1 might be a promising strategy for the treatment of myocarditis.

Flexible strain sensors have received intensive attention owing to their wide application prospects in the fields of wearable, personal electronics, and intelligent robotic systems. But it is a huge challenge for them to possess high sensitivity, fast response, wide sensing range, and superior durability synergistically. In order to solve these issues, we prepared a new type of buckypaper with excellent mechanical properties (elongation at break of about 22%) and electrical conductivity (33 S/cm) by filtering carbon nanotube (CNT) aqueous dispersion mixed with a small amount of natural rubber latex (NR), named natural rubber-buckypaper (N-BP). By taking advantage of the robust N-BP, an NR/N-BP/NR strain sensor was creatively constructed by sandwiching the N-BP with two NR layers using the casting-curing method. The NR/N-BP/NR sandwich strain sensor showed a very high gauge factor value (2280), ultrashort response time (21 ms), very large sensing range (500%), and satisfactory sensing stability (2000 cycles at 100% strain). As for practical application, this NR/N-BP/NR strain sensor could accurately capture large or subtle human body movements, such as limb joint movements and facial movements, and could even distinguish the pronunciation of different English words. As a whole, the NR/N-BP/NR sandwich strain sensor exhibited promising applications in wearable electronics. The NR/N-BP/NR sandwich strain sensor with wide working range and high sensitivity based on the excellent performance of N-BP.

The wearable and self-powered sensors with multiple functions are urgently needed for energy saving devices, economical convenience, and artificial human skins. It is a meaningful idea to convert excess heat sources into power supplies for wearable sensors. In this report, we have fabricated a series of free-standing self-powered temperature-strain dual sensors based on poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS)/carbon nanocoils (CNCs)-poly(vinyl) alcohol composite films by a simple drop casting method. The Seebeck coefficients of the composite films were measured to be 19 μV/K. The sensor, with the addition of CNCs, showed a superior sensing performance to that without CNCs. PEDOT:PSS is used to provide a thermoelectric power to detect temperature changes and strain deformations. The minimum detect limit for the temperature difference was 0.3 K. Under a constant temperature gradient of 30 K, strains from 1 to 10% were detected without any external power supply. The films can be easily made into an array to detect the temperature of the fingers and motions of the wrist by attaching it to the human wrist directly. For the first time, due to the independent action of the thermoelectric material and strain sensing material, the thermoelectric voltage which is generated by a constant temperature difference is maintained under different strains. This kind of free-standing self-powered multifunctional sensors has great application prospects in the fields of healthcare and artificial intelligence in the future.

Elastic textiles are considered to be ideal materials for constructing wearable devices due to their good air permeability, flexibility, and skin affinity. To date, the construction of textile strain sensors has been extensively researched for human motion monitoring applications. However, the development of multifunctional textile sensors with the ability to distinguish multiple external stimuli is still a challenge. In this work, a strategy is proposed to integrate the resistive and capacitive sensors into one device to broaden the sensing capabilities of textile sensors. Carbon particles are coated on nylon/spandex fabrics as strain sensing layers. A simple sewing method was employed to assemble the conductive fabrics into a pristine intermediary fabric to form a capacitive pressure sensor. The resistance and capacitance of this sandwich structure sensor are both sensitive to humidity, temperature, and strain stimuli. The gauge factors of resistive strain, humidity, and temperature sensors are 62.2, 6.27%/% RH and −5.3%/°C, respectively. According to the negative or positive responses of the resistance and capacitance, the applied stimulus can be well-identified. Both the resistive and capacitive sensors exhibit a stable response in more than 5000 cycles. The resistive and capacitive sensing mechanisms have been analyzed. Because of the wearability, stretchability, and unique multi-sensing capabilities, the sensor can be mounted on the human skin or sewed onto clothes and masks to record a series of physiological signals, such as joint bending, wrist pulse, sweating, and respiration, showing great potential in human–machine interactions, personal health monitoring, and the Internet of things.

Highly efficient microwave absorption materials with tunable electromagnetic properties have been attracting extensive attention. However, it still remains a challenge to fabricate the chiral materials decorated with core-shell structured magnetic-particles for excellent microwave absorption performance. Herein, a novel composite of helical carbon nanocoils (CNCs) and Fe3O4@C core-shell structures are synthesized, for the first time, via sequential processes of chemical vapor deposition (CVD) technique and hydrothermal reactions. By controlling the reaction temperature and time in CVD process, the composites with different morphologies and multilevel heterostructural interfaces are obtained. The minimum reflection loss of the CNC/Fe3O4@C composite reaches −47.5 dB at 13.4 GHz with a thickness of only 1.7 mm. Meanwhile, the composite also exhibits an effective frequency range (≤−10 dB) of as wide as 5.03 GHz at a thickness of only 1.5 mm. Our designs not only provide a scalable way for preparing a kind of novel and robust absorber but also offer inspirations for construction of a kind of composite consisting of chiral and core-shell structured materials.

A flexible humidity sensor based on a tissue-carbon nanocoil (CNC)-carbon nanotube (CNT) composite has been investigated. Taking advantage of the excellent water absorption of tissue and the electrical sensitivity of CNCs/CNTs to humidity, this humidity sensor obtains outstanding humidity sensing performance, including a wide sensing range of 10-90% RH, a maximum response value of 492% (Δ

Recently, wearable energy harvesting systems have been attracting great attention. As thermal energy is abundant in nature, developing wearable energy harvesters based on thermal energy conversion processes has been of particular interest. By integration of a high-efficient solar absorber, a pyroelectric film, and thermoelectric yarns, herein, we design a novel wearable solar-energy-driven pyrothermoelectric hybrid generator (PTEG). In contrast to those wearable pyroelectric generators and thermoelectric generators reported in previous works, our PTEG can enable effective energy harvesting from both dynamic temperature fluctuations and static temperature gradients. Under an illumination intensity of 1500 W/m

BACKGROUND: Dilated cardiomyopathy (DCM) is a common cause of heart failure. Cardiac remodeling is the main pathological change in DCM, yet the molecular mechanism is still unclear. Therefore, the present study aims to find potential crucial genes and regulators through bulk and single-cell transcriptomic analysis. METHODS: Three microarray datasets of DCM (GSE57338, GSE42955, GSE79962) were chosen from gene expression omnibus (GEO) to analyze the differentially expressed genes (DEGs). LASSO regression, SVM-RFE, and PPI network methods were then carried out to identify key genes. Another dataset (GSE116250) was used to validate these findings. To further identify DCM-associated specific cell types, transcription factors, and cell-cell interaction networks, GSEA, SCENIC, and CellPhoneDB were conducted on public datasets for single-cell RNA sequencing analysis of DCM (GSE109816 and GSE121893). Finally, reverse transcription-polymerase chain reaction (RT-PCR), western blot, and immunohistochemical were performed to validate DPT expression in fibroblasts and DCM. RESULTS: There were 281 DEGs between DCM and non-failing donors. CCL5 and DPT were identified to be key genes and both genes had a 0.844 area under the receiver operating curve (AUC) in the validation dataset. Further single-cell sequencing analysis revealed three main findings: (I) DPT was mainly expressed in fibroblasts and was significantly upregulated in DCM fibroblasts; (II) DPT(+) fibroblasts were involved in the organization of the extracellular matrix (ECM) and collagen fibrils and were regulated by the transcription factor STAT3; and (III) DPT(+) fibroblasts had high interactions with endothelial cells through including Ephrin-Eph, ACKR-CXCL, and JAG-NOTCH signal pathways. RT-PCR, western blot, and immunohistochemical confirmed that DPT was highly expressed and co-localized with Vimentin and p-STAT3 in DCM patients. STAT3 inhibitor S3I-201 reduced the expression of DPT in mouse cardiac fibroblasts. CONCLUSIONS: DPT could be used as a diagnostic marker and therapeutic target of DCM. DPT(+) fibroblasts could be a novel regulator of the cardiac remodeling process in DCM.

A novel vanelike nanostructure based on the hybridization of carbon nanotubes and carbon nanocoils has been fabricated by a two-step chemical vapor deposition method. A flexible and sensitive strain sensor is prepared by coupling this hybrid structure with polydimethylsiloxane. By regulating the density and length of carbon nanotubes, the gauge factor and strain range of the sensors are tuned from 4.5 to 70 and 9 to 260%, respectively. These sensors exhibit high reliability and stability in a more than 10 000-cycle test and have a prompt response time of less than 37 ms. Owing to the tunable properties, these sensors show great potential in monitoring both subtle and large-scale displacements, which can meet the diverse demands of human motion monitoring.

The incidence of atrial fibrillation (AF) increases after surgery and is associated with the activation of NLRP3-inflammation. Our previous studies have found that transient receptor potential vanilloid 4 (TRPV4) blockade reduces the susceptibility to AF, but its molecular mechanisms remains unclear. Therefore, we hypothesized that blockage of TRPV4 reduces the incidence of AF by inhibiting NLRP3-inflammasome in sterile pericarditis (SP) mice. In this study, we established SP mice by dusting talcum powder on atrial surfaces. We first confirmed that genetic or pharmacological TRPV4 inhibition reduced the susceptibility to AF in SP mice. We also found that the expression level of NLRP3-inflammasome and inflammatory cytokines significantly increased in the atria of SP mice, which further increased in application the TRPV4 agonist GSK1016790A (GSK101) and decreased in application the TRPV4 antagonist GSK2193874. More importantly, ERK inhibitor (U0126) or NF-κB inhibitor (Bay11-7082) could partially reverse GSK101-induced NLRP3-inflammasome up-regulation. Interestingly, U0126 can reversed GSK101-induced NF-κB phosphorylation, but Bay11-7082 cannot change GSK101-induced ERK phosphorylation. Finally, we shown that the activation of NLRP3-inflammasome and ERK/NF-κB signaling pathway significantly reduced in TRPV4-knockout SP mice. Collectively, our studies indicate that blockage of TRPV4 prevents AF in SP mice by inhibiting NLRP3-inflammasome through the ERK/NF-κB signaling pathway.

Hydrogels with specially designed structures and adjustable properties have been considered as smart materials with multi-purpose application prospects, especially in the field of flexible sensors. However, most hydrogel-based sensors have low sensitivity, which inevitably affects their promotion in the market. Herein, a strain sensor comprising a poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) hybrid hydrogel sandwiched between two graphene layers was successfully constructed in a facile way, and it exhibited many excellent properties including extremely high sensitivity. The incorporation of glycerol ensured the good flexibility and anti-freezing performance of the hydrogel-based sensor even at -15 °C. The dynamic coordination bonds in the hydrogel-based sensor endowed it with excellent self-healing properties. In particular, the sandwich-structured hydrogel sensor showed a very high gauge factor (GF) value of 39 at the strain of 50%, which is much higher than those of most ordinary hydrogel-based strain sensors. A super stable signal value after 5000 strain cycles and a very short response time of 274 ms guaranteed the long-term usability and sensitivity of the hydrogel-based sandwich sensor. More importantly, the hydrogel-based sandwich sensor could detect both large and tiny human motions accurately and instantly in a series of real-time monitoring experiments, showing great potential for intelligent wearable electronic devices.

Recently, wearable strain sensors have increasingly attracted much attention due to their potential applications in human motion detection and personal health monitoring. To date, it is still a challenge to fabricate a flexible strain sensor with both comfort and high performance. In this study, we dip the commercially available spandex/polyamide fabric into carbonic pen ink to prepare a textile strain sensor with good skin affinity. The textile strain sensor exhibits a high gauge factor (∼62.9) and an excellent linearity (R2 ∼ 0.99) in the strain range of 0-30%. Both before and after washing, the sensor exhibits high stability in more than 5000 cycles. Owing to the facile integration of the ink-decorated fabric on clothes, the sensor can be conveniently attached to the human body to monitor human motions, thus showing great potential in practical applications.

High-purity (99%) carbon nanocoils (CNCs) have been synthesized by using porous α-Fe2O3/SnO2 catalyst. The yield of CNCs reaches 9,098% after a 6 h growth. This value is much higher than the previously reported data, indicating that this method is promising to synthesize high-purity CNCs on a large scale. It is considered that an appropriate proportion of Fe and Sn, proper particle size distribution, and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs. Benefiting from the high-purity preparation, a CNC Buckypaper was successfully prepared and the electrical, mechanical, and electrochemical properties were investigated comprehensively. Furthermore, as one of the practical applications, the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%. This study provides a facile and economical route for preparing high-purity CNCs, which is suitable for large-quantity production. Furthermore, the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications.

Flexible sensors have wide-ranging application prospects in the field of human health motion monitoring. However, it is still a challenge to design and prepare strain sensors with both high sensitivity and wide operating range. Inspired by the fiber connection structure of lotus root, the carbon nanocoils (CNCs) with large aspect ratio (acting as the lotus root fibers) is used as a conductive bridge to connect the fragile Ti3C2-MXene nanosheet layers, significantly enhancing the sensing range of the sensor. Waterborne polyurethane (WPU) encapsulated strain sensor (Ti3C2/CNCs/WPU) can achieve GF values and sensing ranges of 474 and 220%, respectively. In addition, this sensor shows reliable responses at different frequencies and can withstand more than 1000 stretch-release cycles. More importantly, the composite strain sensor can accurately sense and monitor different limb movements and human body motion states, showing broad application prospects in real-time human health detection.

Articular cartilage (AC) has gradient features in both mechanics and histology as well as a poor regeneration ability. The repair of AC poses difficulties in both research and the clinic. In this paper, a gradient scaffold based on poly(lactic-co-glycolic acid) (PLGA)-extracellular matrix was proposed. Cartilage scaffolds with a three-layer gradient structure were fabricated by PLGA through three-dimensional printing, and the microstructure orientation and pore fabrication were made by decellularized extracellular matrix injection and directional freezing. The manufactured scaffold has a mechanical strength close to that of real cartilage. A quantitative optimization of the Young's modulus and shear modulus was achieved by material mechanics formulas, which achieved a more accurate mechanical bionic and a more stable interface performance because of the one-time molding process. At the same time, the scaffolds have a bionic and gradient microstructure orientation and pore size, and the stratification ratio can be quantitatively optimized by design of the freeze box and temperature simulation. In general, this paper provides a method to optimize AC scaffolds by both mechanics and histology as well as a bionic multimaterial scaffold. This paper is of significance for cell culture and clinical transplantation experiments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1664-1676, 2018.

An ultrahigh-performance multi-functional sensor integrating strain, temperature and humidity sensing has been investigated. The sensing medium is only composed of carbon nanocoils (CNCs) and carbon nanotubes (CNTs). For strain sensing, due to the high elasticity provided by CNC skeleton and the recoverable conductive cracks with a width of hundreds of microns generated by the dense CNT film, the sensor delivers excellent sensing properties, including the advantages of ultrahigh gauge factor (up to 352085), wide strain range (up to 100%), high strain resolution (0.01%), fast response time (16 ms) and robust cycle stability (10000 cycles). In addition, this all–carbon sensing medium can also be used for temperature and humidity sensing in an ultrawide temperature range of 7 to 400 K and humidity sensing over a relative humidity range of 10% to 80% with a high signal-to-noise ratios. It is worth noting that the integrated multi-functional sensor can simultaneously detect the stimuli of strain, temperature and humidity with low coupling. Multiple applications can be detected accurately, such as human motions, breathing behavior, pulse wave, different vibration modes and so on. Therefore, the all-carbon-based sensor provides a promising strategy in developing multi-functional integration for smart wearable devices, electronic skins, and other multi-functional sensing devices.

Previous studies, including our own, have demonstrated that transient receptor potential vanilloid 4 (TRPV4) is involved in myocardial ischemia-reperfusion (IR) injury, yet its underlying molecular mechanism remains unclear. In this study, we isolated mice hearts for a Langendorff perfusion test and used HL-1 myocytes for in vitro assessments. We first confirmed that TRPV4 agonist (GSK101) enhanced myocardial IR injury, as demonstrated by the reduced recovery of cardiac function, larger myocardial infarct size, and more apoptotic cells. We also found that GSK101 could further increase the phosphorylation of JNK and CaMKII in isolated hearts during IR. Notably, GSK101 dose-dependently evoked the phosphorylation of JNK and CaMKII in isolated normal hearts. All above GSK101-induced effects could be significantly blocked by the pharmacological inhibition or genetic ablation of TRPV4. More importantly, JNK inhibition (with SP600125) or CaMKII inhibition (with KN93 or in transgenic AC3-I mice) could prevent GSK101-induced myocardial injury during IR. In HL-1 myocytes, GSK101 triggered Ca2+ influx and evoked the phosphorylation of JNK and CaMKII but these effects were abolished by removing extracellular Ca2+ or in the presence of a TRPV4 antagonist. Finally, we showed that in HL-1 myocytes and isolated hearts during IR, JNK inhibition significantly inhibited the phosphorylation of CaMKII induced by GSK101 but CaMKII inhibition had no effect on JNK activation induced by GSK101. Our data suggest that TRPV4 activation exacerbates myocardial IR injury via the JNK-CaMKII phosphorylation pathway.

The development of miniaturized and wearable electronic devices addresses the demand for novel power-supply systems that have advantages including lightweight, good stretchability, self-sustaining and high compatibility with human skin. To meet these criteria, conducting polymer-based thermoelectric (TE) fibers have recently attracted extensive attention. However, the intrinsically stretchable TE fibers that simultaneously have good TE performance and stability under cyclic loading are still rarely reported. In this work, we have successfully produced high-performance stretchable TE fibers comprising of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS) and waterborne polyurethane (WPU) via a simple one-step wet-spinning approach. In the composite fibers, WPU not only acts as an elastomeric matrix but also has a template effect on improving the packing order and increasing the linearity of the PEDOT chains during wet-spinning. As a result, the PEDOT:PSS/WPU composite fibers exhibited desirable wearable performance, including high power factor (26.1 μW m−1 K−2), good stretchability (>30%) and outstanding TE property stability under cyclic stretching. Their practical applications as stretchable temperature sensors and stretchable TE generators were further demonstrated. The high-performance and intrinsically stretchable TE fibers developed in this work are expected to be applied in various wearable electronics.

Ternary composites as electrode materials have attracted extensive attention due to their excellent electrochemical performance in energy-storage technologies as compared to single or binary composites. Herein, we demonstrated a facile two-step method to construct a new hierarchical nanocomposite by combing buckypaper (BP) with γ-MnOOH nanorods and polyaniline. BP is used as a conductive substrate for the synthesis of free-standing hierarchical electrodes. The structural characterizations revealed the growth of a hierarchical porous structure of the ternary electrode. The synthesized polyaniline@γ-MnOOH–BP ternary composite electrode shows a maximum specific capacitance of 567.5 F g−1 at a current density of 0.5 A g−1 and a relatively high areal capacitance of 301.2 mF cm−2 at a current density of 0.27 mA cm−2. This intriguing result is ascribed to the good combination of BP, γ-MnOOH, and PANI. We believe that this ternary composite electrode has potential in portable, environmentally friendly, and wearable applications for next generation energy-storage devices.

Highlights High-purity (~ 99%) carbon nanocoils (CNCs) without the amorphous carbon layer were synthesized by using porous α-Fe2O3/SnO2 catalyst.The highest yield of the CNCs can reach ~ 9098% after a 6 h growth, which is much higher than those mentioned in previous reports.A CNC Buckypaper was successfully prepared and utilized as an efficient adsorbent for the removal of methylene blue dye with the adsorption efficiency of 90.9%. Electronic supplementary material The online version of this article (10.1007/s40820-019-0365-y) contains supplementary material, which is available to authorized users., High-purity (99%) carbon nanocoils (CNCs) have been synthesized by using porous α-Fe2O3/SnO2 catalyst. The yield of CNCs reaches 9,098% after a 6 h growth. This value is much higher than the previously reported data, indicating that this method is promising to synthesize high-purity CNCs on a large scale. It is considered that an appropriate proportion of Fe and Sn, proper particle size distribution, and a loose-porous aggregate structure of the catalyst are the key points to the high-purity growth of CNCs. Benefiting from the high-purity preparation, a CNC Buckypaper was successfully prepared and the electrical, mechanical, and electrochemical properties were investigated comprehensively. Furthermore, as one of the practical applications, the CNC Buckypaper was successfully utilized as an efficient adsorbent for the removal of methylene blue dye from wastewater with an adsorption efficiency of 90.9%. This study provides a facile and economical route for preparing high-purity CNCs, which is suitable for large-quantity production. Furthermore, the fabrication of macroscopic CNC Buckypaper provides promising alternative of adsorbent or other practical applications. Electronic supplementary material The online version of this article (10.1007/s40820-019-0365-y) contains supplementary material, which is available to authorized users.

Goal: The construction of single-cell array is known as the challenging technology to manipulate cell position and number and accomplish cell analysis in biomedical engineering. Methods: We put forward a novel controllable cell printing technique for rapid, precise, convenient, high cell viability, multicellular, and high-throughput printing. We also proposed a novel microfluidic device to verify the effectiveness of the printing and study the migration ability and anti-cancer drug responses of cancer cell as important applications. Results: This technique offered a minimum process time of 5 min, a maximum positional accuracy of 10 μ m, 0.1 nL liquid volume level per droplet, above 87% cell viability after seven days and the ability to print different multicellular arrays. We found that the cell compared to cell culture in petri dish after 48 h. In addition, there was a significant different inhibition on cancer cells migration ability and cell drug activities with different concentrations of paclitaxel. Conclusion: This novel controllable cell array printing technique on the microfluidic platforms provides a useful method with high-quality printing and cell viability for the applications of single-cell analysis and high-throughput drug screening. Significance: The controllable cell printing technique could apply in many biological processes and biomedical engineering applications, such as cell analysis, cancer development, and drug screening and metabolism. Combined with the microfluidic chips, tissue engineering, and sensors, this technique will be widely used for the construction and analysis of biological and biomedical model.

The development of flexible and stretchable multi-functional sensors addresses the requirements for applications in fields of electronic skins, artificial intelligence and health/structure monitoring. Here, we fabricated a novel self-powered strain-temperature dual-functional sensor based on composite films of carbon nanocoils (CNCs) and a conductive elastomeric blends of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and waterborne polyurethane (WPU). Owing to the high stretchability of helical-structured CNCs, high elasticity of WPU and multiple interfacial contacts between the conducting constitutes, the sensor exhibited large strain detection range of 0-50% and a high sensitivity with gauge factor (GF) of 25. Based on the Seebeck effect arising from the conducting polymer of PEDOT:PSS, the sensor enabled simultaneous detection of temperature changes and strain deformations at a self-powered circumstance. To demonstrate its practical application as a wearable device, the senor was directly attached to the human skin. It not only detected subtle human motion and strain stimuli, but also could distinguish the stimuli from either a warm or a cold objective by telling the difference in their temperature signals. This is the first time that the CNC-based composites are developed for use as a multifunctional sensing medium. Our self-powered strain-temperature dual-functional sensor demonstrates great potential in wearable devices and e-skin applications.

Conducting polymers, particularly poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS), have been intensively studied for thermoelectric (TE) applications, owing to their unique advantages including nontoxicity, low cost, good mechanical flexibility and low thermal conductivity. The TE properties of the conducting polymers show a strong dependence on their polymer chain conformations and chain stacking structures. In this work, one-dimensional PEDOT:PSS fibers were developed to improve the chain packing order and increase the proportions of quinoid PEDOT by the spatial confinement effect arising from the specific fiber configuration. The PEDOT:PSS fibers were produced through a continuous wet-spinning process followed by a one-step treatment with sulfuric acid. The optimized PEDOT:PSS fibers achieved a power factor of 147.8 μW m−1 K−2 with an electrical conductivity of 4029.5 S cm−1 and a Seebeck coefficient of 19.2 μV K−1 at room temperature. The power factor was 15 times that of a two-dimensional PEDOT:PSS film processed at the same condition. Besides, the PEDOT:PSS fibers also exhibited a high tensile strength of 389.5 MPa and a large breaking strain of 30.5%. Based on the PEDOT:PSS fibers, a prototype fibrous TE generator (TEG) was assembled. The fibrous TEG delivered an output power density of ~0.273 μW cm−2 using the human body heat. This work paves the way to developing high-performance organic TE materials by approaches of polymer chain modulation.

Graphene derivatives have great potential in the field of energy storage, because of their high specific surface area, great electrical conductivity, and stable electrochemical properties. For the graphene-based electrodes with a three-dimensional (3D) porous structure, the interlayer stacking of the graphene sheets largely limits their capacitive performance, and thus hinders their wide applications. In this work, we successfully developed a lightweight, freestanding and 3D porous reduced graphene oxide (rGO)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) composite aerogel by incorporating the conducting polymer PEDOT:PSS into interconnected rGO networks through a facile, low-cost and all-water-processable two-step synthesis route. PEDOT:PSS covering on the rGO sheets was found to not only prevent the stacking of rGO sheets, but also greatly improve the ion accessibility and mechanical stability of this highly porous spongy meshwork. Due to the synergistic effect of rGO and PEDOT:PSS, the aerogel electrodes delivered a high gravimetric specific capacitance (471 F g−1 at 0.2 A g−1), an excellent rate capability, and a remarkable capacitance retention (98.71% over 20,000 cycles at 20 A g−1). Furthermore, the aerogel-based symmetric supercapacitor exhibited a wide potential window (0–1.4 V) and an excellent energy storage performance. A high energy density of 48.18 Wh kg−1 with the power density of 1.4 kW kg−1 at 0.5 A g−1, or an energy density of 32.67 Wh kg−1 corresponding to the great power density of 14,000 W kg−1 at 5 A g−1 was achieved. These results demonstrate the great potential of the rGO/PEDOT:PSS aerogel as an excellent electrode material for energy storage applications.

A super strong poly (vinyl alcohol)/poly (acrylic acid) (PVA/PAA) anti-freezing hydrogel fiber has been successfully constructed and studied. The introduction of PVA chains significantly improves tensile strength and toughness to 3.8 MPa and 13.7 MJ/m3, respectively. In addition, glycerol in the hydrogel fiber ensures its good flexibility even in −15 °C. We coat hydrogel fiber with multi-walled carbon nanotubes (MWCNTs) and study their strain sensing properties. The composite hydrogel fiber has a high gauge factor of 25 at the strain of 40%, which is superior to those common hydrogel-based strain sensors. Notably, the composite hydrogel fiber shows a high stability and repeatability of 5000 cycles, and a fast response time of 225 ms. Besides, the composite hydrogel fiber can detect the large and subtle body movements accurately and timely. Therefore, this composite hydrogel fiber may be a very hopeful candidate for wearable sensing devices.

Liver-on-chip, due to its precision and low cost for constructing in vitro models, has tremendous potential for drug toxicity testing and pathological studies. By applying APAP (acetaminophen) treatment of different concentrations, a dynamic self-circulating liver lobule model for drug testing was proven useful for emulating the human physiological system. However, the demand for a dynamic system of on-chip organs is difficult to fulfil due to the relatively cumbersome fabrication processes. In this paper, the design and fabrication of an AC electrothermal self-circulating system combined with a 3D biomimetic liver lobule is described. The system was fabricated using a low-cost ITO laser etching process within a few seconds. A large number of interdigital electrodes were arranged in a limited space to increase the fluid flow-driven efficiency. The liver lobule consists of two parts, a hepatocyte cell-laden layer and an endothelial layer, which exhibit a sandwich radial shaped pattern that is more bionic in structure and function. By evaluating the velocity and temperature in the self-circulating system at various voltages and frequencies, we obtained a set of reliable input parameters to provide an adequate supply of culture fluid without cell damage. The metabolism of the liver lobule in dynamic culture and static culture was compared based on cell viability, albumin secretion and urea synthesis.

Articular cartilage (AC) has gradient features in both mechanics and histology as well as a poor regeneration ability. The repair of AC poses difficulties in both research and the clinic. In this paper, a gradient scaffold based on poly(lactic-co-glycolic acid) (PLGA)-extracellular matrix was proposed. Cartilage scaffolds with a three-layer gradient structure were fabricated by PLGA through three-dimensional printing, and the microstructure orientation and pore fabrication were made by decellularized extracellular matrix injection and directional freezing. The manufactured scaffold has a mechanical strength close to that of real cartilage. A quantitative optimization of the Young's modulus and shear modulus was achieved by material mechanics formulas, which achieved a more accurate mechanical bionic and a more stable interface performance because of the one-time molding process. At the same time, the scaffolds have a bionic and gradient microstructure orientation and pore size, and the stratification ratio can be quantitatively optimized by design of the freeze box and temperature simulation. In general, this paper provides a method to optimize AC scaffolds by both mechanics and histology as well as a bionic multimaterial scaffold. This paper is of significance for cell culture and clinical transplantation experiments. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1664-1676, 2018.

Cancer biology and drug discovery are heavily dependent on conventional 2D cell culture systems. However, a 2D culture is significantly limited by its ability to reflect 'true biology' of tumor in vivo. Three-dimensional (3D) in vitro cell culture models have been introduced to aid cancer drug discovery by better modeling the tumor microenvironment. Here, decellularized lung scaffolds cultured with MCF-7 cancer cells were bioengineered as a platform to study tumor development and anti-cancer drug evaluation. Excellent cell compatibility of decellularized lung scaffolds promoted cell growth and proliferation. Multicellular tumor cell spheroids (tumoriods) were formed and enlarged exclusively in decellularized lung scaffolds over time. The expression of breast cancer biomarkers (BRCA1 and HER2) in MCF-7 cells significantly increased in the lung matrix compared to those cultured in 2D systems. Insufficient oxygen and nutrient diffusion into the internal surface of lung scaffolds resulted in intracellular hypoxia, quantified by a significant upregulation of HIF-1α protein expression compared to that of cell monolayers. Higher survival rates after exposure to 5-FU were observed in lung scaffolds (52.04%) compared to that in 2D systems (18.39%) on day 3 of culture. Overall, this new breast tumor system provides a promising platform to study breast cancer progression and develop new targeted therapeutic strategies.