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Polydimethysiloxane (PDMS)-based materials are emerging as an ideal category of flexible multifunctional membranes that are expected to be used for wearable and skin-attachable pressure sensors. He...

New oxygen and pressure sensitive paints (PSPs) with four-arm polymeric structures were prepared by using a kind of controlled living polymerizations – atom transfer radical polymerization (ATRP). The polymers composing of poly(isobutyl methacrylate)-co-poly(trifluoroethyl methacrylate)s (PolyIBMA-co-PolyTFEM)s act as the matrices for the platinum porphyrin-based phosphorescence probes, which were copolymerized in the matrices. The polymers were characterized by using 1H NMR, 19F NMR, and GPC to demonstrate their successful preparation. The influence of polymer structures on sensing activity including the sensitivity and response time to oxygen and/or pressure was investigated. Results showed that copolymers with suitable compositions (herein P3) can have highest sensitivity. Polymer structure’s influence on response time to oxygen was also investigated. For increasing the polymer’s surface area for further improving sensing sensitivity, electrospinning method was used for preparing films with micro-spherical or fibrous structures. The morphologies of electrospinning coated films were observed by SEM. Results showed that electrospinning coated films can respond much better to oxygen and pressure than their corresponding sprayed plates. This is the first time to apply the controlled living polymerization approach to prepare PSPs with multi-arm structures, which will broaden the PSP functional materials’ design strategy.

Conjugated polyelectrolytes (CPEs) have been successfully applied in organic photovoltaics and organic light-emitting diodes, and recently those with inorganic cations became to serve as a hole-transporting layer (HTL) in inverted perovskite solar cells (iPSCs), whereas the CPE HTL materials with organic cations are really limited. In this work, we design a CPE whose side-chains are end-capped by CH3NH3+ cations, the same cations as that in the perovskite layer. The CPE is found to be more compatible to the perovskite material, and shows stronger abilities to reduce the traps both at the surface and in the bulk of the perovskite layer, compared with the typical poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS). The resulting iPSC presents much improved photovoltaic properties and a better long-term stability, with a power conversion efficiency of 19.76%, which is the highest value ever reported for iPSCs based on CPE HTLs.

Polymeric microfibers, particularly the fluorinated copolymers’ fibers, are promising functional materials for photoelectric devices, sensing, and energy storage due to their various surface characteristics. However, to obtain the high fluorine content copolymer-based fibers with considerable uniformity is likely to be especially challenging, which seriously debilitates their applications in sensor devices. Herein, for the first time, we presented a high fluorine content platinum porphyrin-grafted poly(isobutyl methacrylate-co-dodecafluoroheptyl methacrylate) copolymers (PtTFPP-p(IBM-co-DFHMA)) microfibrous thin-films used as optical oxygen sensors. The porous thin-film frameworks were formed of uniform microfibers, which afforded an exceptional improvement in sensitivity and exhibited 584% higher sensitivity than the solid sensing film owing to the large specific surface area, porous structures and oxygen diffusion enhancement by fluorine elements. Additionally, the remarkable emission intensity-changing characteristic of the microfiber sensing film under various air pressures facilitates convenient visualization of pressure distributions on film surface. The characteristics are particularly important for the computational fluid dynamics simulations in various sensing fields such as unsteady flow visualization and unsteady pressure measurements, etc. Owing to its attractive advantages and versatile performance, fluorine-containing copolymers fibers are expected to provide a new strategy for the rational design of high performance gas sensor devices.

A two-photon absorbing (2PA) red emitter group was chemically conjugated onto amphiphilic poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) copolymers, and further grafted with cyclo (Arg-Gly-Asp) (cRGD) peptide to form micelle 1. Micelle 1 with cRGD targeting groups were used for targeted bioimaging. For comparison, micelle 2 without the cRGD targeting groups were also prepared and investigated. The micelles were characterized using dynamic light scattering (DLS), showing average diameters of around 77 nm. The cRGD targeting group is known to bind specifically with α(v)β(3) integrin in cancer cells. In this study, α(v)β(3) integrin overexpressed human glioblastoma U87MG cell line and α(v)β(3) integrin deficient human cervical cancer HeLa cell line were chosen. Results showed that the cRGD targeting group enhanced the cellular uptake efficiency of the micelles significantly in α(v)β(3) integrin rich U87MG cells. Higher temperature (37 °C versus 4 °C) and calcium ions (with 3M calcium chloride in the cell culture medium versus no addition of calcium ions) enhanced the cellular uptake efficiency, suggesting that the uptake of the micelles is through the endocytosis pathway in cells. A 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) viability assay was used to evaluate the cytotoxicity of the micelles and no significant cytotoxicity was observed. The BTD-containing two-photon absorbing emitter in the micelles showed a two-photon absorbing cross-section of 236 GM (1GM = 1 × 10(−50) cm(4) s photon(−1) molecule(−1)) at 820 nm, which is among the highest values reported for red 2PA emitters. Because of the two-photon absorbing characteristics, micelle 1 was successfully used for two-photon fluorescence imaging targeted to U87MG cells under a two-photon fluorescence microscope. This study is the first report regarding the targeted imaging of a specific cancer cell line (herein, U87MG) using the BTD-conjugated-fluorophore-containing block copolymers.

Large-scale industrialization of flexible printed electronics will thrive on advanced functional conductive pastes with excellent properties such as high electrical conductivity and mechanical stability. Herein, we develop an effective method to simultaneously decrease the electrical resistivity and improve the mechanical stability of silver-resin-based conductors by adding a small amount of nanostructured polyaniline (PANI). PANI nanomaterials for improving the properties of conductive composites were synthesized by a facile and repeatable chemical oxidative polymerization method and characterized. Significant improvements in electrical performance were observed. For example, for the 60 wt% silver-filled flexible conductors, the addition of 0.5 wt% PANIs reduces their electrical resistivity to one-thirtieth (from 1253.1 × 10−5 Ω cm to 37.1 × 10−5 Ω cm). After adding 0.5 wt% PANIs, the bending stability (ΔR/R0) was also greatly improved from 92% to 2.3% (about 1/40th). Meanwhile, elastic conductors showed a much better performance in resistance stability and fatigue life (5 times longer than before) during stretching cycles after the addition of PANIs. A bendable printed circuit and a printed tensile resistive sensor were fabricated using the above PANIs to enhance conductive composites, which proved their potential applications in flexible printed circuits, stretchable pressure sensors, and e-skin or other fields.

PurposeIn this study, we use the hypoxia targeting agent (GdDO3NI, a nitroimidazole-based T1MRI contrast agent) for imaging hypoxia in the injured brain after experimental traumatic brain injury (TBI) using magnetic resonance imaging (MRI), and validate the results with immunohistochemistry (IHC) using pimonidazole.MethodsTBI induced mice (controlled cortical impact model) were imaged at 7T using a T2weighted fast spin-echo sequence to estimate the extent of the injury. The mice were then were intravenously injected with either conventional T1agent (gadoteridol) or GdDO3NI at 0.3 mmol/kg dose (n=5 for each cohort) along with pimonidazole (60 mg/kg). Mice were imaged pre- and post-contrast using a T1-weighted spin-echo sequence for three hours. Regions of interests were drawn on the brain injury region, the contralateral brain as well as on the cheek muscle region for comparison of contrast kinetics. Brains were harvested immediately post imaging for immunohistochemical analysis.ResultsGdDO3NI is retained in the injury region for up to 3 hours post-injection (p< 0.05 compared to gadoteridol) while it rapidly clears out of the muscle region. On the other hand, conventional MRI contrast agent gadoteridol clears out of both the injury region and muscle rapidly, although with a relatively more delayed wash out in the injury region. Minimal contrast enhancement was seen for both agents in the contralateral hemisphere. Pimonidazole staining confirms the presence of hypoxia in both gadoteridol and GdDO3NI cohorts, and the later cohort shows good agreement with MRI contrast enhancement.ConclusionGdDO3NI was successfully shown to visualize hypoxia in the brain post-TBI using T1-wt MRI.

Introduction: To investigate the effectiveness of the case management mode on the application of smear-positive pulmonary tuberculosis patients. Methodology: This was a randomized control trial. A total of 70 newly diagnosed smear-positive pulmonary tuberculosis patients were recruited and been randomly divided into experimental group and control group, with 35 participants in each group. In the experimental group, patients received the tuberculosis case management mode based on the conventional management mode. In the control group, patients received the routine management mode. We compared the knowledge, attitude, and practice score; sputum-negative conversion rate, effective imaging rate of the two groups at the time of initial admission, discharge, and one month after discharge. Results: The results showed that there was no significant difference in baseline data between the two groups (p > 0.05); at the time of discharge and one month after discharge, the knowledge, belief, behavior, sputum-negative conversion rate, and imaging examination effective rate of the experimental group were higher than those of the control group (p < 0.05). Conclusions: The case management mode can improve the knowledge, attitude, and practice level; sputum-negative conversion rate; and imaging efficiency of newly treated smear-positive pulmonary tuberculosis patients.

Metasurface is an artificially arranged sub-wavelength micro-structure array, where each structure can be regarded as a unit cell that is controlled by electromagnetic waves. Recently, bifunctional metasurfaces have garnered increasing interest and become excellent candidates for device miniaturization and integration. In this study, we propose a highly efficient bifunctional metasurface composed of silicon nanopillars, enabling beam anomalous refraction and focusing at visible wavelength. Based on the proposed metasurface, the other two metasurfaces demonstrating high-order beam anomalous refraction and focusing are designed successfully. This work will establish a positive prospect for the development of high-performance bifunctional metasurfaces.

Root hair elongation relies on polarized cell expansion at the growing tip. As a major osmotically active ion, potassium is expected to be continuously assimilated to maintain cell turgor during hair tip growth. However, due to the lack of practicable detection methods, the dynamics and physiological role of K+ in hair growth are still unclear. In this report, we apply the small-molecule fluorescent K+ sensor NK3 in Arabidopsis root hairs for the first time. By employing NK3, oscillating cytoplasmic K+ dynamics can be resolved at the tip of growing root hairs, similar to the growth oscillation pattern. Cross-correlation analysis indicates that K+ oscillation leads the growth oscillations by approximately 1.5 s. Artificially increasing cytoplasmic K+ level showed no significant influence on hair growth rate, but led to the formation of swelling structures at the tip, an increase of cytosolic Ca2+ level and microfilament depolymerization, implying the involvement of antagonistic regulatory factors (e.g., Ca2+ signaling) in the causality between cytoplasmic K+ and hair growth. These results suggest that, in each round of oscillating root hair elongation, the oscillatory cell expansion accelerates on the heels of cytosolic K+ increment, and decelerates with the activation of antagonistic regulators, thus forming a negative feedback loop which ensures the normal growth of root hairs.

Capillary electrophoresis sodium dodecyl sulfate (CE-SDS), either in reduced (rCE-SDS) or non-reduced (nrCE-SDS) form, is widely used for purity evaluation and impurity analysis of monoclonal antibody (mAb) drugs. The accuracy of the method may be interfered by artificial species resulted from sample preparation or electrophoresis operation if it is not well optimized. In a routine analysis of pertuzumab for both innovator Perjeta® and biosimilar HLX11 samples, a cluster of unknown peaks located between light chain (LC) and heavy chain (HC) were observed in rCE-SDS and making the purity of (LC + HC)% unacceptable. They can hardly be reduced by regular method optimization such as changing buffer pH, denaturing temperature or incubation time to achieve the (LC + HC)% expectation. Here, the peaks are first characterized and determined to be non-covalently formed LC-LC dimers by multiple techniques including reversed-phase liquid chromatography-mass spectrometry (LC–MS). These artifacts are then eliminated through enhancing capillary separation temperature to 60 °C and decreasing the separation voltage to 9.5 kV, an unusual CE-SDS operation setting. Finally, a developed rCE-SDS method is presented for successful evaluation of pertuzumab purity and impurities, which is further confirmed by an alternative reduced microchip-based gel electrophoresis. In summary, the developed method provided an accurate and reliable purity evaluation and size variant profiling for batch releasing, stability testing and quality study of reduced pertuzumab samples.

The potassium ion (K

The first NIR fluorescent mitochondria-targeting K+ sensor, denoted as TAC-Rh, was developed. The produced sensor consists of a rhodamine analog as the fluorophore and triazacryptand (TAC) as the K+ recognition unit. Compared to the K+ sensors reported previously, TAC-Rh exhibits two unique optical properties: the largest Stokes shifts (120 nm) and the longest emission peak wavelength (720 nm). With the assistance of this novel sensor, real-time changes of K+ concentrations in mitochondria during apoptosis were monitored for the first time. Moreover, it was also the first time that the relationship between mitochondrial K+ flux and apoptosis was investigated in real time using fluorescence imaging.

Real-time, continuous and non-invasive glucose monitoring is essential for the health of diabetic. In this work, we developed soft and transparent smart contact lenses which could detect glucose in tear with high sensitivity. The smart contact lenses were prepared by immobilizing a sensitive glucose fluorescent probe and another reference fluorescent dye into the hydrogel network of the contact lenses. With the increase of glucose concentration, the fluorescent color of the smart contact lenses changed from pink to blue. The fluorescent images could be collected by a smartphone and transformed into RGB signals to quantify the glucose levels. These smart contact lenses could successfully monitor glucose level of 23 μM–1.0 mM in tears by a smart phone. The animal experiments further demonstrate the biosafety of smart contact lenses and the potential application of glucose monitoring. The fluorescence sensor platform is expected to be a new method for painless glucose monitoring.

Electrochromic devices (ECDs) can alter their optical transmittances under external electrical power but are unable to spontaneously modulate the light flow in real-time along with the intensity change of surrounding light. To address this problem, a module of smart perovskite solar cell (PSC)-powered all-in-one gel ECDs was reported. The PSC-powered ECDs could modulate their transmittance swiftly in visible-infrared regions, hence regulating the photo energy flow in real time according to the surrounding light intensity. The ECD based on 4, 4′-(thiophene- 2, 5-diyl)bis(1-ethylpyridin-1-ium) diiodide (TEV) showed large optical contrast (79.7% at 570 nm, 64.9% at 908 nm), excellent coloration efficiency (231.2 cm2/C), and outstanding stability (only 1.1% ΔT change after 60,000 cycles). The PSC-powered ECDs showed fast response time (≤5 s) and high stability (negligible degradation after 5000 s consecutive switching between bright and dark conditions in air). Meanwhile, the stored power accompanied with the electrochromic process could drive a red LED with high cyclic stability (95.6% of areal capacitance maintained after 10,000 charging-discharging cycles), indicating that ECDs can serve as ideal electrochromic supercapacitors (ECSs). In addition, the fabricated ECD with large area (5.0 cm × 5.4 cm) showed excellent thermal regulation (7 °C of temperature difference between colored and bleached states). We expect this work would pave a new way to save energy and improve energy efficiency in modern buildings and automobiles.

Mono-dispersed polystyrene-based microspheres with diameters about 1 μm encapsulating rhodamine moieties as oxygen insensitive internal reference probes and platinum octaethylporphyrin units as oxygen sensitive probes were synthesized as new ratiometric oxygen sensors (Rhod-PtOEP-PS). The dual luminophors of rhodamines and platinum porphyrin moieties exhibited emissions maxima at 585 nm and 644 nm, respectively. The microspheres showed good oxygen sensing properties in different oxygen partial pressures (pO2) and dissolved oxygen (DO) concentrations. It was found the oxygen probes and reference probes in microspheres showed higher photo-stability than their corresponding free fluorophores in solution. The microspheres also showed good sensitivity for air-pressure and cellular oxygen in cell culture medium. These microspheres were used to detect DOs in a few kinds of liquids including some daily drinks and it was found the measured errors were within positive/negative 11% as compared with the measured results using traditional oxygen electrodes.

An amphiphilic graft copolymer (P3) composed of poly(oligo (ethylene glycol) methacrylate) (POEGMA) as a hydrophilic segment and a polystyrene (PS) as a hydrophobic chain was prepared. P3 was used to incorporate a highly efficient hydrophobic oxygen probe platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) in its micelles to enable the application of PtTFPP in aqueous solution for biosensing. For achieving ratiometric oxygen sensing, a hydrophobic conjugated polymer (CP) was used as a fluorescence resonance energy transfer (FRET) donor for PtTFPP - the FRET acceptor. Results showed that diameters of these nano-oxygen sensors ranging from 50 to 60 nm and FRET efficiency as high as 98% could be achieved. Further, FRET contributed to the brightness of PtTFPP in micelles. High quantum yields of PtTFPP in non-FRET micelles and FRET micelles under nitrogen were achieved to be 0.109 and 0.231, respectively. The sensors were found to be able to measure oxygen concentrations from 0.082 to 40.9 mg/L at room temperature with linear Stern-Volmer constants. These sensors were also demonstrated to be suitable for monitoring extracellular oxygen consumption of E. Coli and HeLa cells. This study illustrated a feasible approach to achieve highly efficient ratiometric oxygen sensors without specific structure modification of the efficient PtTFPP probe, however using an amphiphilic graft copolymer approach.

Perovskite nanocrystals (PNCs) have emerged as advanced materials for various applications. Herein, we developed oxygen insensitive PNCs in polymer matrices and applied them as internal reference to achieve ratiometric sensing for oxygen. Significant emission color changes from orange under nitrogen to green under oxygen were observed. Further micro-patterned sensors were prepared by micro/nano-imprint technology. Results showed that all these micro-structures increased sensors’ sensitivity, however, affected sensors response time significantly. The film with pinholes slowed down the response times; the films with pillars shorted the response time. Therefore, for the first time we prepared new PNCs-based ratiometric gaseous oxygen sensing films and further prepared micro-structured sensors. This study may broaden the applications of perovskite materials and also oxygen sensors.

In this work, we presented the robust and magnetically recoverable dual sensor particles that are capable of real-time monitoring of dissolved oxygen (DO) and glucose concentrations in aqueous solutions. The dual sensor consists of glucose oxidase-functionalized polyethylenimine-coated Fe3O4 particles (Fe3O4@PEI-GOD) and sub-micro-sized Fe3O4-modified poly(Platinum porphyrin-co-Styrene) ((PtTFPPMA-PS)@Fe3O4) fluorescent spheres. The dual sensing functions originate from the cascade catalysis amplification driven by the recyclable Fe3O4@PEI-GOD particles and glucose oxidase consumption of oxygen in the process of glucose oxidation. Consequently, the (PtTFPPMA-PS)@Fe3O4 fluorescent spheres exhibited higher fluorescence intensity due to the effective alleviation of fluorescence quenching effect raised from the decrease of DO. The remarkable fluorescence intensity-changing characteristics of the solutions facilitate convenient identification of oxygen concentrations and glucose concentrations even with naked eyes. Thanks to the magnetically recoverable superiority, the recycle study proved that the multifunctional particles could be repeatedly utilized without significant catalytic activity loss after 10 cycles. Interestingly, the sensing film comprising the (PtTFPPMA-PS)@Fe3O4 fluorescent spheres can also be applied to the unsteady pressure measurement and unsteady air flow visualization due to its remarkable light intensity-changing features.

Sensitivity enhancement of optical oxygen sensors is crucial for the characterization of nearly anoxic systems and oxygen quantification in trace amounts. In this work, for the first time we presented the introduction of silver nanowires (AgNWs) as a sensitivity booster for optical oxygen sensors based on AgNWs–palladium octaethylporphine–poly(methyl methacrylate) (AgNWs@PdOEP–PMMA) microfiber mats prepared by electrospinning. Herein, a series of sensing microfiber mats with different loading ratios of high aspect ratio AgNWs were fabricated, and the corresponding sensitivity enhancement was systematically investigated. With increasing incorporated ratios, the AgNWs@PdOEP–PMMA-sensing microfiber mats exhibited a swift response (approx. 1.8 s) and a dramatic sensitivity enhancement (by 243% for the range of oxygen concentration 0−10% and 235% for the range of oxygen concentration 0–100%) when compared to the pure PdOEP–PMMA microfiber mat. Additionally, the as-prepared sensing films were experimentally confirmed to be highly photostable and reproducible. The advantages of AgNW-induced sensitivity enhancement could be useful for the rational design and realization of revolutionary highly sensitive sensors and expected to be readily applicable to many other high-performance gas sensor devices.

A novel side-chain polymer was designed and synthesized by integrating a methoxytriphenylamine-conjugated-thiophene moiety as the hole transporting material (HTM) unit on a polystyrene side-chain (HTM–P1) by the radical polymerization of its relevant monomer (HTM–M1). These two materials and their similar model compound without the styrene moieties (HTM2) were used as the HTMs for perovskite solar cells (PSCs). The results showed that with similar device preparation and measurement conditions, the hole mobility of polymer HTM–P1 was about 3 times and 2.5 times that of HTM2 and HTM–M1, respectively. PSCs based on HTM–P1 as the dopant-free HTM afford an impressive highest power conversion efficiency of 17.2%, which is much higher than those obtained from HTM2 (3.2% without the dopant and 14.7% with the dopant) and HTM–M1 (9.7%). Moreover, the devices based on the HTM–P1 presented significantly higher stability than the device based on its model compound of HTM2. Hence, this study demonstrates that the side-chain polymer strategy is an effective approach to achieve high efficiency and highly stable PSCs using dopant-free HTMs.

Dysfunction of potassium ion (K+) channels are closely related to various diseases, while the current tools for studying K+ channels are indirect methods that cannot measure the flux of K+ in live cells. Herein, we prepared K+ fluorescent nanoprobes (KFK-Cat NPs) with appropriate dissociation constant (Kd) value (127 mM K+) and excellent stability, especially photostability, for intracellular K+ sensing and imaging. An easy-operating and biocompatible method for functional measurement of human ether-a-go-go-related gene (hERG) channel activity was constructed via directly monitoring the fluctuation of K+ in KFK-Cat NPs stained hERG-HEK293 cells. Further, this method was efficient for screening of hERG channel inhibitors, the results were in accordance with the traditional patch-clamp technique and the commercially available thallium ion (Tl+) fluorescent probes assay kits. The KFK-Cat NPs were also capable of K+ imaging after endocytosed by hERG-overexpressing colon cancer cells. This work, for the first time, broadens the application of K+ fluorescent probes for functional analysis of K+ channels activity under the help of confocal laser scanning microscope (CLSM). This method shows significant potentials for drug screening and provides efficient tool for deep investigation of K+ channel-related diseases, including tumor.

Two novel hole transporting materials (HTMs) bearing thermally cross-linkable styryl groups were developed and applied for perovskite solar cells. These HTMs could be in situ cross-linked under mild temperature. The resulted cross-linked HTMs form smooth, solvent-resistant films, which enables the subsequent spin-coating of perovskite layer. In addition, the fluorination approach successfully leads to strong interactions between HTM, formamidine (FA) and lead in perovskite, resulting in the passivation of the perovskite film. The device using the HTM with fluorine moieties (HTM-F) showed higher power conversion efficiency (PCE) of 20.51% than that of the device using fluorine-free HTM (HTM-H) of 19.07%. Moreover, the device with HTM-F exhibits better stability, retaining 90% of the initial PCE after 2000 h under ambient air and 91% of the initial PCE after 1000 h under 85 °C heating.

Two new block copolymers (P1 and P2) containing platinum porphyrin-based phosphorescent probes with different molar ratios of polydimethylsiloxane (PDMS) and isobutyl methacrylate (IBM) were successfully synthesized via atom transfer radical polymerization (ATRP) with narrow polydispersity smaller than 1.21. For comparison, P3 without the PDMS block was also prepared. Results of 1H NMR and GPC demonstrated their successful preparation. Oxygen sensing performance and pressure sensitivity of these polymers were investigated. Results showed that the polymer with more PDMS contents exhibited higher oxygen sensitivity, better pressure sensitivity, and faster response time. The pressure sensitivity of polymer with more PDMS contents was affected more significantly by temperature. The polymer P1 with a fraction of PDMS of 50 wt% reported herein showed a high pressure sensitivity of 0.82%/kPa, which is among the highest ones of the reported polymers. These results may provide helpful information for broadening the development of oxygen sensors and pressure sensitive paints.

In this work, we presented a facile and cost-effective approach to fabricate novel PtTFPP/PDMS micro-pillar array (MPA) sensor film with I0/I100 for gaseous oxygen and dissolved oxygen are 288 and 84, respectively. The sensitivity of the sensor film exhibited over ∼30-fold increment when compared with contemporary PtTFPP/PDMS-based oxygen sensors. The detection limit was as low as 0.10 μmol/L, which means that the ultrasensitive sensor films enable reliable monitoring of dissolved oxygen (DO) within nanomolar concentration ranges that are particularly difficult to achieve in previous works. Furthermore, the remarkably light intensity-changing characteristic of the sensing film under lower O2 partial pressures facilitates convenient identification of O2 concentrations even with the naked eye. We believe that the proposed device could be a promising candidate in various oxygen sensing fields such as nearly anoxic systems, unsteady pressure measurement and unsteady flow visualization, etc.

A graft copolymer composed of poly(e-caprolactone) as a hydrophobic chain and poly(N-(2-hydroxypropyl)methacrylamide) as a hydrophilic segment with an internal reference probe for oxygen sensing was prepared. Highly efficient platinum(II)meso-tetra(pentafluorophenyl)porphine (PtTFPP) was used as a typical oxygen probe. Although PtTFPP was highly efficient, it is hydrophobic, limiting its direct application for oxygen sensing in biological conditions. By using the amphiphilic graft copolymer, PTTFPP was successfully incorporated into the micelles formed by this polymer to not only enable the application of PtTFPP for biosensing in medium but also retain its high efficiency. The quantum efficiency of PtTFPP in the micelle solution under nitrogen can reach as high as 0.20. The PtTFPP-containing micelles were tested for high throughput cell respiration and bacteria detection. The influence of an antibiotic, antimycin as a representative example, on cell respiration was also studied. For achieving high accurate sensing, an internal built-in reference probe with aggregation induced emission properties were also polymerized in the graft copolymer. This study demonstrated that the graft polymer approach is a good way to enable highly efficient and hydrophobic oxygen probes for biosensing.

A new two-layer sensor film was constructed for sensing glucose based on glucose oxidase and oxygen sensing material. The first layer of film containing the oxygen sensor and intra-reference material was polymerized, then the second layer of glucose oxidase and glutaraldehyde was formed on the oxygen sensor layer. The two-layer sensor film has a resolution up to 0.05 mM and a detection range from 0 to 5 mM to glucose. The effects of pH and temperature on the sensing performance were systematically investigated. The selective detection of glucose among other monosaccharides, such as fructose, mannose and galactose indicated that the sensing film has excellent selectivity. The prepared sensor was successfully applied for glucose sample detection of glucose concentration in artificial tears. Keywords: Glucose sensor, Glucose oxidase, Fluorescence, Oxygen film, Diabetes

Two novel electron-rich linear small-molecules, containing benzene and thiophene as the cores with arylamine side groups, named HTM1 and HTM2, respectively, were synthesized via short, easy and efficient synthetic routes. The influence of the π-linkers of the two materials on photophysical, electrochemical, and thermal properties, and hole mobility and photovoltaic performance was investigated. The compound with thiophene as π-linker (HTM2) shows better solubility and higher hole-transporting mobility than the compound with benzene as π-linker (HTM1). When these two materials were incorporated into perovskite solar cells as hole transporting materials (HTMs), short circuit photocurrent densities (Jscs) of 15.83 mA cm−2 and 21.1 mA cm−2, open circuit voltages (Vocs) of 0.79 V and 1.09 V, and fill factors (FFs) of 0.46 and 0.62, were obtained. These factors contributed to average overall power conversion efficiencies (PCEs) of 6.4% and 13.9% with the best PCEs of 7.5% and 14.7%, respectively. The performance of HTM2 is comparable to the PCE obtained using the current state-of-the-art HTM of 2,2′,7,7′-tetrakis(N,N′-di-p-methoxyphenylamine)-9,9′-spirobifluorene (spiro-OMeTAD) with the best PCE of 17.4% using a similar device preparation method and measurement conditions. These results showed that selecting a suitable π-linker is important for the performance of HTMs. And the simple HTM2 material is a promising HTM with the potential to replace the expensive spiro-OMeTAD due to its comparable performance with a much simpler synthesis route and much reduced cost (10 times less than that of spiro-OMeTAD). This study demonstrates that a compound with a suitable π-linker could be a low-cost and high performance HTM to replace spiro-OMeTAD.

Herein, we report an innovative application of doping conjugated-polypyrrole nanoparticles (PPy NPs) into electrically conductive adhesives (ECAs) to prepare low-electrical resistivity interconnecting materials. PPy NPs were synthesized via a facile one-step chemical oxidative polymerization method at room temperature with the average diameter as small as 86.8 nm. Particles' diameters and dispersity were manipulated under different polymerization conditions through the adjustment of weight percentages and molecular weights of polyvinylpyrrolidone (PVP) as the surfactants. Results showed that higher concentrations of PVP and the longer chains of PVPs resulted in smaller diameters of PPy NPs. We also found that a suitable portion of ethanol in the polymerization mixtures gives rise to a better dispersity than that observed in mixtures without ethanol. When a small amount of PPy NPs was added into traditional epoxy resin-based and silver-flakes-filled ECAs, the resistance measurements showed an enhancement in the electrical conductivity, or in other words, a reduction in resistivity significantly. For example, the electrical resistivity of 70 wt% silver-filled ECAs was reduced from 1.6 × 10−3 Ω cm to 9.4 × 10−5 Ω cm by using only 2.5 wt% PPy NPs as the dopants. Thus, our results confirmed new applications of PPy NPs in the field of ECAs for decreasing the resistance, reducing the dosage of silver in ECAs, and achieving flexible devices. Finally, flexible electrical patterns were printed on paper and polyimide substrates were used as conducting circuits to light LED devices.

Organic–inorganic hybrid 3-(trimethoxysily)propylmethacrylate-co-platinum porphyrin-co-methacrylolsobutyl-polyhedral oligomeric silsesquioxane (TPMA-PtTPP-POSS) copolymer films were synthesized and applied as high-performance oxygen sensors. High sensitivity and fast response characteristics originate from the POSS-containing copolymer composition and wormlike structures. The wormlike structures composed of the POSS-containing copolymers self-assembled on the film surface can ensure the homogeneous dispersion of PtTPP and can be perturbed by a trace oxygen environment. Compared with the state-of-the-art PtTPP-TPMA film, the TPMA-PtTPP-POSS copolymer sensors exhibit a swift response (approx. 0.6 s), long-term stability, higher sensitivity (increased by 4-fold), and a relatively large dynamic range, etc. We believe that the POSS-containing hybrid films should provide a new strategy for designing sensitive and fast responding optical oxygen sensors.

Integrating an oxygen-sensitive probe (OSP) onto a three-dimensional (3D) microstructure substrate is a plausible technique to significantly improve the sensitivity of oxygen sensors. Despite the fact that polydimethylsiloxane (PDMS) matrices are regarded as the ideal sensory support, there are still no reports on an OSP functionalized flexible PDMS-based micropillar array (PDMS-MPAs) film as an optical oxygen sensor with capabilities to efficiently improve the sensor's overall performance, e.g. sensitivity, detection limit and stability against photo-bleaching. Herein, we reported the covalent bonding of a functional copolymer of platinum porphyrin (PtTPP)/3-(trimethoxysily)propylmethacrylate (PtTPP/TPMA) as the OSP on the surface of hydroxyl-modified PDMS-MPAs through a “grafting reaction” between PtTPP/TPMA and PDMS-MPAs. The homogeneous dispersion and well-isolated arrangement of the PtTPP/TPMA OSP on the 3D PDMS-MPA surface can ensure that the grafted OSP efficiently quenches the oxygen molecules. Consequently, the 3D PtTPP/TPMA-PDMS-MPA sensor film gives rise to a high fluorescence quenching efficiency of about 95% at 1 atm O2 (I0/I100 = 23) and 96% in aqueous solution (I0/IO2satu = 16) with an excellent linear Stern–Volmer plot (ksv = 0.1 h Pa−1, R2 = 0.997 in gas atmosphere and ksv = 12.8 mmol−1 L, R2 = 0.999 in aqueous solution, respectively), excellent reversibility and an ultra-low detection limit (4.7 μmol L−1) when compared with state-of-the-art PDMS-based oxygen sensors. Apart from the competitive sensitivity, the highly durable, reusable superiorities of the 3D PtTPP/TPMA-PDMS-MPA film can further facilitate the exploration and realization of the presented strategy for future oxygen sensor applications, such as the characterization of nearly anoxic systems in harsh environments.

Three four-arm amphiphilic block copolymers with different chain lengths, consisting of a hydrophilic chain of polyethylene glycol (PEG) and hydrophobic segment of polycaprolactam (PCL), were synthesized and used to encapsulate the high-efficient and hydrophobic oxygen probe of platinum(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin (PtTFPP) to form polymer micelles. This approach enabled the use of PtTFPP in aqueous solution for biosensing. Experimental results demonstrated that the particle sizes of these nano-oxygen sensors between 40.0 and 203.8 nm depend on the structures of block copolymers. PtTFPP in these micelles showed an effective quantum yield under nitrogen environment, ranging from 0.06 to 0.159. The new sensors are suitable for analyzing dissolved oxygen concentrations in the range of 0.04&ndash, 39.3 mg/L by using the linear Stern&ndash, Volmer equation at room temperature. In addition, it has been shown that these sensors are capable of in situ monitoring the dissolved oxygens in the culture medium of E. coli and Romas cells during the respiration process, and distinguishing the drug activity of antibiotic ampicillin from that of antimycin A. This study showed that the use of these nanostructured multi-arm block copolymer micelles can achieve efficient biological applications without specific structural modification of the hydrophobic PtTFPP probe, which is expected to have broad prospects.

It is essential to develop a novel and versatile strategy for constructing electrically conductive adhesives (ECAs) that have superior conductivity and high mechanical properties. In this work, easily synthesized polyaniline@cellulose (PANI@CNs) nanowhiskers with a high aspect ratio and excellent solubility in 1,4-dioxane were prepared and added to conventional Ag-containing adhesives. A small amount of PANI@CNs can dramatically tune the structure of the ECAs&rsquo, conductive network and significantly improve the conductivity of the ECAs. Good solubility of PANI@CNs in solvents brings excellent dispersion in the polymer matrix. Thus, a three-dimensional (3D) conducting network formed with dispersed PANI@CNs and Ag flakes can enhance the conductivity of ECAs. The conductivity of the ECAs (with 1.5 wt% PANI@CNs and 55 wt% Ag flakes) showed three orders of magnitude higher than that of the ECAs filled with 55 wt% Ag flakes and 65 wt% Ag flakes. Meanwhile, the integration of PANI@CNs with Ag flakes in polymer matrices also significantly enhanced the mechanical compliance of the resulted ECAs. The resistivity remained unchanged after rolling the PANI@CNs-containing ECAs&rsquo, film into a 4 mm bending radius for over 1500 cycles. A bendable printed circuit was fabricated using the above PANI@CNs-containing ECAs, which demonstrated their future potential in the field of flexible electronics.

The development of flexible pressure sensors has attracted increasing research interest for potential applications such as wearable electronic skins and human healthcare monitoring. Herein, we demonstrated a piezoresistive pressure sensor based on AgNWs-coated hybrid architecture consisting of mesoscaled dome and microscaled pillar arrays. We experimentally showed that the key three-dimensional component for a pressure sensor can be conveniently acquired using a vacuum application during the spin-coating process instead of a sophisticated and expensive approach. The demonstrated hybrid structure exhibits dramatically improved sensing capability when compared with the conventional one-fold dome-based counterpart in terms of the sensitivity and detectable pressure range. The optimized sensing performance, by integrating D1000 dome and D50P100 MPA, reaches a superior sensitivity of 128.29 kPa-1 (0-200 Pa), 1.28 kPa-1 (0.2-10 kPa), and 0.26 kPa-1 (10-80 kPa) and a detection limit of 2.5 Pa with excellent durability. As a proof-of-concept, the pressure sensor based on the hybrid configuration was demonstrated as a versatile platform to accurately monitor different kinds of physical signals or pressure sources, e.g., wrist pulse, voice vibration, finger bending/touching, gas flow, as well as address spatial loading. We believe that the proposed architecture and developed methodology can be promising for future applications including flexible electronic devices, artificial skins, and interactive robotics.

Side-chain polymers have the potential to be excellent dopant-free hole-transporting materials (HTMs) for perovskite solar cells (PSCs) because of their unique characteristics, such as tunable energy levels, high charge mobility, good solubility, and excellent film-forming ability. However, there has been less research focusing on side-chain polymers for PSCs. Here, two side-chain polystyrenes with triphenylamine substituents on carbazole moieties were designed and characterized. The properties of the side-chain polymers were tuned finely, including the photophysical and electrochemical properties and charge mobilities, by changing the positions of triphenylamine substituents on carbazole. Owing to the higher mobility and charge extraction ability, the polymer P2 with the triphenylamine substituent on the 3,6-positions of the carbazole unit showed higher performance with power conversion efficiency (PCE) of 18.45%, which was much higher than the PCE (16.78%) of P1 with 2,7-positions substituted. These results clearly demonstrated that side-chain polymers can act as promising HTMs for PSC applications and the performance of side-chain polymers could be optimized by carefully tuning the structure of the monomer, which provides a new strategy to design new kinds of side-chain polymers and obtain high-performance dopant-free HTMs.

Electrically switchable photonic crystals are demonstrated based on TiO

Electrically conductive adhesives (ECAs) are one of the low temperature bonding materials. It can be used to replace toxic Sn-Pb solder. The key issue for the application of ECAs is how to improve their electrical properties. In the present study, we develop an effective method to promote the electrical properties of ECAs by addition of polyaniline (PANI) nanoparticles. PANIs were synthesized via a facile one-step chemical oxidative polymerization method. After adding 0.5 wt% PANI nanoparticles, the conductivity of ECAs increased dramatically by an order of magnitude. The bulk resistivity of 8.8 &times, 10&minus, 5 &Omega, &middot, cm is achieved for 65 wt% silver fillers with 0.5 wt% PANIs loaded ECAs. Besides, this improvement has no negative effect on the shear strength and the aging life of ECAs. Moreover, the use of PANIs not only lowers the percolation threshold of ECAs, but also reduces the cost and improves the bonding reliability. Finally, PANIs enhanced ECAs patterns were successfully printed by a stencil printing method, which proved their potential applications in replacing conventional solder pastes and printing functional circuits.

EDTA-bonded multi-connected carbon-dots (EDTA-C-dots) were prepared from carbon dot precursors and complexed with Eu

Monitoring extracellular pH (pHe) is important for biology understanding, since pHe and its homeostasis are closely relevant to cellular metabolism. Hydrogel-based pHe sensors have attracted significant attention and showed wide application, while they are tedious with significant time-cost operation and reproducibility variations for high-throughput application. Herein, we synthesized two polymers for pHe monitoring which are soluble in water at room temperature with easy operations and high reproducibility among various micro-plate wells for high-throughput analysis. P1 (P(OEGMA-co-MEO2MA-co-pHS)) and P2 (P(OEGMA-co-pHS)) were synthesized via the Reversible Addition Fragmentation Chain Transfer (RAFT) copolymerization of oligo(ethylene glycol) methacrylate (OEGMA), 2-(2′-methoxyethoxy) ethyl methacrylate (MEO2MA) and the pH sensitive fluorescence moiety N-fluoresceinyl methacrylamide (pHS). P1 is soluble in water at room temperature (25 °C) while insoluble at the temperature above 33 °C, indicating its feature of lower critical solution temperature (LCST) at 33 °C. Further P1 showed higher pH sensitivity and photostability than P2 (without LCST property) when used at physiological temperature (37 °C). Thus, P1 was chosen to in-situ monitor the micro-environmental acidification of E. coli, Hela and Ramos cells during their growth, and the metabolism inhibiting activity of a representative antibiotic, ampicillin. Cell concentration-dependent cellular acidification and drug concentration-dependent inhibition of cellular acidification were observed, demonstrating that the LCST polymer (P1) is suitable for real-time cellular acidification monitoring as well as for high-throughput drug screening. This study firstly demonstrated the use of a LCST polymeric sensor for high-throughput screening of antibiotics and investigation of cell metabolism.

Here, we propose and numerically demonstrate an all-dielectric metalens based on crystalline silicon metasurface. This metalens consists of circular pillars array and can achieve beam focusing with high transmission efficiency at visible wavelength.

Background: Globally, lung cancer is the second most cause of deaths, which accounts for approximately 29% of the cancer cases worldwide. d-Carvone is considered a vital constituent of many essential oils with immense pharmacological benefits. Objective: In this study, we examined the immunomodulatory effect of d-carvone in the Swiss albino mice model against benzo(a)pyrene (BaP)-induced lung carcinoma. Materials and Methods: BaP was orally administered to the mice (50 mg/kg body weight [bw] for 4 weeks [twice a week]). Post-BaP administration, d-carvone (20 mg/kg bw) was orally administered to the mice (20 mg/kg bw). We calculated the tumor incidence and performed the following measurements: lung and bw, hematological parameters, immune complexes (phagocytic and avidity indexes, nitroblue tetrazolium reduction, soluble immune complex levels, immunocompetent cells (leukocytes, lymphocytes, and neutrophils), immunoglobin (Ig) levels (IgG, IgA, and IgM), level of xenobiotics and enzymes that point toward hepatic dysfunction, carcinoembryonic antigen (CEA), and proinflammatory cytokines (PICs) in experimental and normal mice. The level of oxidative stress in the experimental animals was investigated. The lung tissues of investigational animals were examined for the histopathological changes. Results: According to the results, there was an increased level of lipid peroxidation and decreased level of antioxidant activity in the lung tumor samples. The counts of lymphocytes, polymorphonuclear cells, and macrophages were notably decreased and increased, respectively, by the d-carvone post-treatment. Moreover, BaP-induced inflammation that is indicated by the increased in the level of PICs and CEA proteins in lung samples. d-Carvone attenuated the levels of PICs and CEA. Conclusion: The results of this study reveal that d-carvone prevented the cells against BaP-induced inflammation in lung cancer without causing adverse effects.

Luminescence including fluorescence and phosphorescence sensors have been demonstrated to be important for studying cell metabolism, and diagnosing diseases and cancer. Various design principles have been employed for the development of sensors in different formats, such as organic molecules, polymers, polymeric hydrogels, and nanoparticles. The integration of the sensing with fluorescence imaging provides valuable tools for biomedical research and applications at not only bulk-cell level but also at single-cell level. In this article, we critically reviewed recent progresses on pH, oxygen, and dual pH and oxygen sensors specifically for their application in microbial cells. In addition, we focused not only on sensor materials with different chemical structures, but also on design and applications of sensors for better understanding cellular metabolism of microbial cells. Finally, we also provided an outlook for future materials design and key challenges in reaching broad applications in microbial...

Mono-dispersed platinum octaethylporphyrin/polystyrene (PtOEP/PS) fluorescent spheres were synthesized by a soap-free emulsion polymerization for the detection of dissolved oxygen (DO), in which hydrophobic PtOEP as indicator is embedded in PS spheres during the synthesis procedure. The performance of the PtOEP/PS spheres-based optical oxygen sensor was evaluated by recording their fluorescence intensities in different oxygen (O2) environments. Results suggest that PtOEP/PS spheres exhibit good oxygen sensing properties with fast response time and reliable photo-stability after several months of storage.

The inflammasome is a caspase-1-activating complex that is implicated in a growing number of acute and chronic pathologies. Interest has increased in identifying small molecular inhibitors of inflammasome signaling because of its role in clinically relevant diseases. It was recently reported that the protein tyrosine kinase, Syk, regulates pathogen-induced inflammasome signaling by phosphorylating a molecular switch on the adapter protein ASC. However, several aspects of the role of Syk in inflammasome signaling and the effects of its inhibition remain unclear. The aim of the present study is to explore in detail the effects of the oxindole Syk inhibitor OXSI-2 on various aspects of nigericin-induced inflammasome signaling. Our results indicate that OXSI-2 inhibits inflammasome assembly, caspase-1 activation, IL-1β processing and release, mitochondrial ROS generation, and pyroptotic cell death. Using a novel live cell potassium sensor we show that Syk inhibition with OXSI-2 has no effect on potassium efflux kinetics and that blockade of potassium efflux with extracellular potassium alters Syk phosphorylation. The effects of OXSI-2 identified in this study provide context for the role of Syk in inflammasome signaling and demonstrate its importance in oxidative signaling upstream of inflammasome activation and downstream of ion flux.

Extracellular pH has a strong effect on cell metabolism and growth. Precisely detecting extracellular pH with high throughput is critical for cell metabolism research and fermentation applications. In this research, a series of ratiometric fluorescent pH sensitive polymers are developed and the ps-pH-neutral is characterized as the best one for exclusive detection of extracellular pH. Poly(N-(2-hydroxypropyl)methacrylamide) (PHPMA) is used as the host polymer to increase the water solubility of the pH sensitive polymer without introducing cell toxicity. The fluorescent emission spectra from the polymeric sensor under excitation at the isosbestic point 455 nm possess two fluorescence peaks at 475 nm and 505 nm, which have different responding trends to pH. This enables the polymer to detect pH using fluorescent maxima at 475 nm and 505 nm (I475 nm/I505 nm) ratiometrically. The cell impermeability ensures the sensor can solely detect the environmental pH. The sensor is tested to detect the extracellular pH of bacteria or eukaryotic cells in high throughput assays using a microplate reader. Results showed that the pH sensor can be used for high throughput detection of extracellular pH with high repeatability and low photobleaching effect.

Due to its designability, metasurfaces have been widely used to implement various miniaturized optical components, especially the lenses. However, most of the lenses currently designed tend to have high aspect ratios, which greatly hinders their practical applications. Among the various types of metasurfaces, Huygens' metasurfaces offer a new perspective, which utilize the spectrally overlapping electric dipole (ED) and magnetic dipole (MD) Mie-type resonances to achieve efficient wave-front control. Here, we proposed and designed Huygens’ metasurfaces that can efficiently manipulate linearly polarized light to perform beam focusing (73% transmission efficiency for cylindrical lens and 68% transmission efficiency for aspheric lens) at near-infrared wavelengths. Additionally, the most significant advantage of the proposed metasurface is that it has a low aspect ratio, which makes it an ideal platform for future integration on optical chip.

Over the past few years, surface pressure measurement has fundamental importance in many areas, particularly, aerodynamic research. Conventional methods involve pressure taps, but due to the nature of these pressure taps, only pressure information of isolated points on model surface is available, which limit their applications in aerodynamics studies. Recently the newly developed approach, pressure sensitive paint (PSP) has revolutionized such pressure measurements and various PSP materials have been developed for aerodynamics research. Hence, the main focus of this review is to study the interactions of polymers with different oxygen probes and polymeric role as supporting material in the maturation of PSP. In this review, the selected PSP materials are categorically elucidated in terms of their advantages and limitations to give a fair insight about their applicability. Further, we have summarized and articulated such particular optical oxygen sensing materials either that have been used as PSP or have potential to be used as PSP materials.