Unveiling the role of proton concentration in dinuclear metal complexes for boosting photocatalytic CO2 reduction.

The reaction kinetics of photocatalytic CO2 reduction is highly dependent on the transfer rate of electrons and protons to the CO2 molecules adsorbed on catalytic centers. Studies on uncovering the proton effect in catalysts on photocatalytic activity of CO2 reduction are significant but rarely reported. In this paper, we, from the molecular level, revealed that the photocatalytic activity of CO2 reduction is closely related to the proton availability in catalysts. Specifically, four dinuclear Co(II) complexes based on Robson-type ligands with different number of carboxylic groups (-nCOOH; n = 0, 2, 4, 6) were designed and synthesized. All these complexes show photocatalytic activity for CO2 reduction to CO in a water-containing system upon visible-light illumination. Interestingly, the CO yields increase positively with the increase of the carboxylic-group number in dinuclear Co(II) complexes. The one containing -6COOH shows the best photocatalytic activity for CO2 reduction to CO, with the TON value reaching as high as 10,294. The value is 1.8, 3.4, and 7.8 times higher than those containing -4COOH, -2COOH, and -0COOH, respectively. The high TON value also makes the dinuclear Co(II) complex with -6COOH outstanding among reported homogeneous molecular catalysts for photocatalytic CO2 reduction. Control experiments and density functional theory calculation indicated that more carboxylic groups in the catalyst endow the catalyst with more proton relays, thus accelerating the proton transfer and boosting the photocatalytic CO2 reduction. This study, at a molecular level, elucidates that more carboxylic groups in catalysts are beneficial for boosting the reaction kinetics of photocatalytic CO2 reduction.

One-Shot Single-Cell Proteome and Metabolome Analysis Strategy for the Same Single Cell.

Characterizing the profiles of proteome and metabolome at the single-cell level is of great significance in single-cell multiomic studies. Herein, we proposed a novel strategy called one-shot single-cell proteome and metabolome analysis (scPMA) to acquire the proteome and metabolome information in a single-cell individual in one injection of LC-MS/MS analysis. Based on the scPMA strategy, a total workflow was developed to achieve the single-cell capture, nanoliter-scale sample pretreatment, one-shot LC injection and separation of the enzyme-digested peptides and metabolites, and dual-zone MS/MS detection for proteome and metabolome profiling. Benefiting from the scPMA strategy, we realized dual-omic analysis of single tumor cells, including A549, HeLa, and HepG2 cells with 816, 578, and 293 protein groups and 72, 91, and 148 metabolites quantified on average. A single-cell perspective experiment for investigating the doxorubicin-induced antitumor effects in both the proteome and metabolome aspects was also performed.

Lab at home: a promising prospect for on-site chemical and biological analysis.

The continuing pursuit for a healthy life has led to the urgent need for on-site analysis. In response to the urgent needs of on-site analysis, we propose a novel concept, called lab at home (LAH), for building automated and integrated total analysis systems to perform chemical and biological testing at home. It represents an emerging research area with broad prospects that has not yet attracted sufficient attention. In this paper, we discuss the urgent need, challenges, and future prospects of this area, and the possible roadmap for achieving the goal of LAH has also been proposed.

Regulation of the Metal Center and Coordinating Anion of Mononuclear Ln(III) Complexes to Promote an Efficient Luminescence Response to Various Organic Solvents.

A series of mononuclear lanthanide complexes [Ln(L1)(NO3)3], (Ln = Dy(III), 1; Tb(III), 3; and Eu(III), 4; L1 = (N1E,N2E)-N1,N2-bis((1-methyl-1H-benzo[d]imidazol-2-yl)methylene)cyclohexane-1,2-diamine) is obtained by reacting N-methylbenzimidazole-2-carbaldehyde (L2) and 1,2-cyclohexanediamine (L3) with Ln(NO3)3·6H2O under solvothermal conditions. L1 ligand is produced via an in situ Schiff base reaction of two molecules of L2 and one molecule of L3. The metal center Ln(III) is in a N4O6 environment formed by L1 and NO3-. NaSCN is added on the basis of 1 synthesis. One SCN- replaces one of the three coordinated NO3- anions in the 1 structure, and the complex [Dy(L1)(NO3)2(SCN)]·CH3CN (2) is synthesized. The complex 1 shows excellent luminescence response to petroleum ether (PET), an organic solvent. To the best of our knowledge, this study is the first to use a complex for sensing responses to PET. When the metal center is changed, the obtained mononuclear complexes 3 and 4 show an excellent luminescence response to tetrahydrofuran (THF). Lastly, 2 obtained by changing the coordinating anion shows an excellent luminescence response to dichloromethane. Herein, for the first time, we regulate the metal center and coordinating anion of lanthanide complexes to adjust the recognition and response of these complexes to different organic solvents.

Multifunctional Binuclear Ln(III) Complexes Obtained via In Situ Tandem Reactions: Multiple Photoresponses to Volatile Organic Solvents and Anticounterfeiting and Magnetic Properties.

The design and synthesis of simple lanthanide complexes with multiple functions have been widely studied and have faced certain challenges. Herein, we successfully synthesized the series of binuclear lanthanide complexes [Ln2(L1)2(NO3)4] (HL1 = 2-amino-1,2-bis(pyridin-2-yl)ethanol; Ln = Dy (Dy2), Tb (Tb2), Ho (Ho2) Er (Er2)) via the in situ self-condensation of Ln(NO3)3·6H2O-catalyzed 2-aminomethylpyridine (16 steps) under solvothermal conditions. Dy2 was mixed with different volatile organic solvents, and photoluminescence tests demonstrated that it showed an excellent selective photoresponse to chloroform (CHCl3). Sensing Tb2 on different organic solvents under the same conditions showed that it exhibited excellent selective photoresponse to methanol (CH3OH). Even under EtOH conditions, Tb2 could selectively respond to small amounts of CH3OH. To the best of our knowledge, achieving a selective photoresponse to various volatile organic compounds by changing the metal center of the complex is difficult. Furthermore, we performed anticounterfeiting tests on Tb2, and the results showed significant differences between the anticounterfeiting marks under white light and ultraviolet light conditions. The alternating current susceptibilities of Dy2 suggested that it was a typical single-molecule magnet (SMM) (Ueff = 93.62 K, τ0 = 1.19 × 10-5 s) under a 0 Oe dc field. Ab initio calculations on Dy2 indicated that the high degrees of axiality of the constituent mononuclear Dy fragments are the main reasons for the existence of SMM behavior.

Substitution Effects Regulate the Formation of Butterfly-Shaped Tetranuclear Dy(III) Cluster and Dy-Based Hydrogen-Bonded Helix Frameworks: Structure and Magnetic Properties.

The generation of two types of complexes with different topological connections and completely different structural types merely via the substitution effect is extremely rare, especially for -CH3 and -C2H5 substituents with similar physical and chemical properties. Herein, we used 3-methoxysalicylaldehyde, 1,2-cyclohexanediamine, and Dy(NO3)3·6H2O to react under solvothermal conditions (CH3OH:CH3CN = 1:1) at 80 °C to obtain the butterfly-shaped tetranuclear DyIII cluster [Dy4(L1)4(µ3-O)2(NO3)2] (Dy4, H2L1 = 6,6'-((1E,1'E)-(cyclohexane-1,3-diylbis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol)). The ligand H2L1 was obtained by the Schiff base in situ reaction of 3-methoxysalicylaldehyde and 1,2-cyclohexanediamine. In the Dy4 structure, (L1)2- has two different coordination modes: µ2-η1:η2:η1:η1 and µ4-η1:η2:η1:η1:η2:η1. The four DyIII ions are in two coordination environments: N2O6 (Dy1) and O9 (Dy2). The magnetic testing of cluster Dy4 without the addition of an external field revealed that it exhibited a clear frequency-dependent behavior. We changed 3-methoxysalicylaldehyde to 3-ethoxysalicylaldehyde and obtained one case of a hydrogen-bonded helix framework, [DyL2(NO3)3]n·2CH3CN (Dy-HHFs, H2L2 = 6,6'-((1E,1'E)-(cyclohexane-1,3-diylbis(azanylylidene))bis(methanylylidene))bis(2-ethoxyphenol)), under the same reaction conditions. The ligand H2L2 was formed by the Schiff base in situ reaction of 3-ethoxysalicylaldehyde and 1,2-cyclohexanediamine. All DyIII ions in the Dy-HHFs structure are in the same coordination environment (O9). The twisted S-shaped (L2)2- ligand is linked by a Dy(III) ion to form a spiral chain. The spiral chain is one of the independent units that is interconnected to form Dy-HHFs through three strong hydrogen-bonding interactions. Magnetic studies show that Dy-HHFs exhibits single-ion-magnet behavior (Ueff = 68.59 K and τ0 = 1.10 × 10-7 s, 0 Oe DC field; Ueff = 131.5 K and τ0 = 1.22 × 10-7 s, 800 Oe DC field). Ab initio calculations were performed to interpret the dynamic magnetic performance of Dy-HHFs, and a satisfactory consistency between theory and experiment exists.

Forming a Large-Scale Droplet Array in a Microcage Array Chip for High-Throughput Screening.

Forming a large-scale droplet array plays an important role for microfluidic droplet-based high-throughput screening and analysis. Herein, we describe a simple and rapid method to form a large-scale two-dimension (2D) droplet array by using a microcage array chip. Differing from the previous droplet array formation methods, microcages formed by being surrounded by multiple micropillars could rapidly spread the oil phase through the gaps between the micropillars and trap droplets with fast speed and convenient operation. We formed a large-scale 2D monolayer droplet array containing approximately 1 000 000 droplets on a 5.5 cm × 5.5 cm microcage array chip within 90 s. The droplets in the droplet array could be further incubated for performing biochemical reactions and detected by a fluorescence microscope in real time. Due to the exact trapping and positioning functions of the microcages to the droplets, single targeted fluorescent droplets in the array could be individually picked out and transferred to culture medium by a microfluidic droplet-handling robot with a success rate of 100% and a picking operation time of 2.0 s for one droplet under the optimized conditions. This system was validated in the screening of the bacterium expressing the esterase AFEST from a mixture of AFEST-expressing and phosphotriesterase-expressing E. coli cells, achieving a success rate of 100% for single-droplet picking while maintaining the bacterial cell viability. The present system has the potential to be applied in high-throughput screening and analysis, such as single cell analysis, directed evolution, and drug screening.

Miniaturization of the Whole Process of Protein Crystallographic Analysis by a Microfluidic Droplet Robot: From Nanoliter-Scale Purified Proteins to Diffraction-Quality Crystals.

To obtain diffraction-quality crystals is one of the largest barriers to analyze the protein structure using X-ray crystallography. Here we describe a microfluidic droplet robot that enables successful miniaturization of the whole process of crystallization experiments including large-scale initial crystallization screening, crystallization optimization, and crystal harvesting. The combination of the state-of-the-art droplet-based microfluidic technique with the microbatch crystallization mode dramatically reduces the volumes of droplet crystallization reactors to tens nanoliter range, allowing large-scale initial screening of 1536 crystallization conditions and multifactor crystallization condition optimization with extremely low protein consumption, and on-chip harvesting of diffraction-quality crystals directly from the droplet reactors. We applied the droplet robot in miniaturized crystallization experiments of seven soluble proteins and two membrane proteins, and on-chip crystal harvesting of six proteins. The X-ray diffraction data sets of these crystals were collected using synchrotron radiation for analyzing the structures with similar diffraction qualities as conventional crystallization methods.

Learning Shapelets for Improving Single-Molecule Nanopore Sensing.

The nanopore technique employs a nanoscale cavity to electrochemically confine individual molecules, achieving ultrasensitive single-molecule analysis based on evaluating the amplitude and duration of the ionic current. However, each nanopore sensing interface has its own intrinsic sensing ability, which does not always efficiently generate distinctive blockade currents for multiple analytes. Therefore, analytes that differ at only a single site often exhibit similar blockade currents or durations in nanopore experiments, which often produces serious overlap in the resulting statistical graphs. To improve the sensing ability of nanopores, herein we propose a novel shapelet-based machine learning approach to discriminate mixed analytes that exhibit nearly identical blockade current amplitudes and durations. DNA oligomers with a single-nucleotide difference, 5'-AAAA-3' and 5'-GAAA-3', are employed as model analytes that are difficult to identify in aerolysin nanopores at 100 mV. First, a set of the most informative and discriminative segments are learned from the time-series data set of blockade current signals using the learning time-series shapelets (LTS) algorithm. Then, the shapelet-transformed representation of the signals is obtained by calculating the minimum distance between the shapelets and the original signals. A simple logistic classifier is used to identify the two types of DNA oligomers in accordance with the corresponding shapelet-transformed representation. Finally, an evaluation is performed on the validation data set to show that our approach can achieve a high F1 score of 0.933. In comparison with the conventional statistical methods for the analysis of duration and residual current, the shapelet-transformed representation provides clearly discriminated distributions for multiple analytes. Taking advantage of the robust LTS algorithm, one could anticipate the real-time analysis of nanopore events for the direct identification and quantification of multiple biomolecules in a complex real sample (e.g., serum) without labels and time-consuming mutagenesis.

Upregulation of Long Non-Coding RNA ENST00000429227.1 Is Correlated with Poor Prognosis in Human Hepatocellular Carcinoma.

BACKGROUND Long non-coding RNAs (lncRNAs) have been shown to play an important regulatory role in many tumors. This study was designed to investigate the expression of lncRNA ENST00000429227.1 in hepatocellular carcinoma (HCC) and to determine whether the expression of lncRNA ENST00000429227.1 affects the prognosis of HCC. MATERIAL AND METHODS lncRNA ENST00000429227.1 showing differences in expression between M1 and M2 was screened by microarray expression measurements. Quantitative real-time PCR (qRT-PCR) was used to detect the expression of lncRNA ENST00000429227.1 in 161 HCC patients. The chi-square test was used to evaluate the relationship between the expression of ENST00000429227.1 and clinicopathological parameters. A survival curve was drawn and analyzed by Kaplan-Meier method. Cox regression was used for univariate and multivariate analysis to determine whether lncRNA ENST00000429227.1 is an independent factor of the occurrence and prognosis of HCC. RESULTS A total of 3703 differentially expressed lncRNAs were obtained, of which 1777 were upregulated and 1926 were downregulated, with multiple change >1.5. The expression of lncRNA ENST00000429227.1 was upregulated in M2 cells. The expression of lncRNA ENST00000429227.1 in HCC tissues was higher than that in adjacent normal tissues (p<0.05), which was correlated with pathological parameters such as surgical margin (p=0.042), AFP (p=0.022) and Barcelona Clinic Liver Cancer (BCLC) stage (p=0.008). Survival analysis showed that high expression of lncRNA ENST00000429227.1 was associated with a decrease in overall survival (OS) rate of HCC patients. Cox regression analysis showed that high expression of ENST00000429227.1 may be an independent risk factor affecting the prognosis of HCC patients. CONCLUSIONS The results suggest that upregulation of ENST00000429227.1 is associated with poor prognosis of HCC patients, and may be a new biomarker for the diagnosis of HCC.

Downregulation of Macrophage-Derived T-UCR uc.306 Associates with Poor Prognosis in Hepatocellular Carcinoma.

BACKGROUND/AIMS: Increasing evidence suggests that T-UCRs are involved in the development of cancer. In this study, we evaluated the role of a macrophage-derived T-UCR, uc.306, in the prognosis of hepatitis B (HBV)-related hepatocellular carcinoma (HCC). METHODS: The uc.306 was obtained by screening microassay data obtained during the polarization of U937 cells from the M2 to M1 phenotype. Uc.306 and macrophage molecule markers were detected by qPCR. Immunohistochemical (IHC) assays were used to examine the M1/M2 status of 90 paired HCC tissues. Kaplan-Meier tests and multivariable Cox regression models were used to analyze predictive confidences, survival, and risk factors. RESULTS: In total, 2,977 differentially expressed T-UCRs were obtained, of which 257 showed fold changes >1.5. The uc.306 was upregulated in M1 cells and was predicted to be involved in the Wnt pathway. The IHC results showed that M1 macrophages (CD68+) were present in the para-tumor tissues, while the M2 phenotype (CD163+) was mainly in the HCC tissues. Uc.306 had a lower expression in the HCC tissues than in that of the para-tumor tissues in 30 paired HCC training sets (P < 0.0001), and 252 paired HCC testing sets (P < 0.0001). Low expression of uc.306 was significantly associated with a shorter overall survival (P < 0.05). CONCLUSIONS: The uc.306 may be a promising biomarkerfor HBV-related HCC, providing a novel marker for the prognosis of HCC.

Triptolide inhibits proliferation and invasion of colorectal cancer cells by blocking Nrf2 expression.

Triptolide (TPL), the main active ingredient of Tripterygium wilfordii, has anti-inflammatory, immunomodulatory, and antitumor actions. It can also inhibit cell proliferation and metastasis while promoting apoptosis of several tumors, such as colorectal cancer (CRC). However, the mechanism of TPL against CRC is not clear. This study was designed to investigate the effects and molecular mechanisms of TPL on the proliferation and invasion ability of CRC cells. A human CRC cell line (HT29 cell line) cultured in vitro was treated with different concentrations of TPL (0, 25, 50, and 100 nmol/L). The proliferation of cells was detected by MTT, the invasion ability of cells by Transwell, and the apoptosis level by flow cytometry. The protein expression levels of nuclear factor-erythroid 2-related factor 2 (Nrf2), matrix metalloproteinase (MMP)-2, and MMP-9 were detected by western blotting. After transfection with sh-Nrf2, HT29 cells were divided into NC group, NC + TPL group and sh-Nrf2 + TPL group, and the above assays were repeated for each group. TPL significantly inhibited the proliferation and invasion ability of HT29 cells and promoted apoptosis (p < .05). Notably, its inhibitory or promotional effects were concentration-dependent, which were enhanced with increasing drug concentration (p < .05). After silencing Nrf2 expression, the proliferation, and invasion ability of HT29 cells were further significantly inhibited while cells apoptosis was further promoted (p < .05). Besides, the decreased Nrf2 expression reduced the protein expression levels of MMP-2 and MMP-9 (p < .05). TPL can effectively inhibit the proliferation and invasion while promoting apoptosis of HT29 cells. And its mechanism of action may be related to the inhibition of Nrf2 signaling expression.

Pick-up single-cell proteomic analysis for quantifying up to 3000 proteins in a Mammalian cell.

The shotgun proteomic analysis is currently the most promising single-cell protein sequencing technology, however its identification level of ~1000 proteins per cell is still insufficient for practical applications. Here, we develop a pick-up single-cell proteomic analysis (PiSPA) workflow to achieve a deep identification capable of quantifying up to 3000 protein groups in a mammalian cell using the label-free quantitative method. The PiSPA workflow is specially established for single-cell samples mainly based on a nanoliter-scale microfluidic liquid handling robot, capable of achieving single-cell capture, pretreatment and injection under the pick-up operation strategy. Using this customized workflow with remarkable improvement in protein identification, 2449-3500, 2278-3257 and 1621-2904 protein groups are quantified in single A549 cells (n = 37), HeLa cells (n = 44) and U2OS cells (n = 27) under the DIA (MBR) mode, respectively. Benefiting from the flexible cell picking-up ability, we study HeLa cell migration at the single cell proteome level, demonstrating the potential in practical biological research from single-cell insight.

A Floating Capsule Electrochemical System for In Situ and Multichannel Ion-Selective Sensing.

Free-floating electrochemical sensors are promising for in situ bioprocess monitoring with the advantages of movability, a lowered risk of contamination, and a simplified structure of the bioreactor. Although floating sensors were developed for the measurement of physical and chemical indicators such as temperature, velocity of flow, pH, and dissolved oxygen, it is the lack of available electrochemical sensors for the determination of the inorganic ions in bioreactors that has a significant influence on cell culture. In this study, a capsule-shaped electrochemical system (iCapsuleEC) is developed to monitor ions including K+, NH4+, Na+, Ca2+, and Mg2+ based on solid-contact ion-selective electrodes (SC-ISEs). It consists of a disposable electrochemical sensor and signal-processing device with features including multichannel measurement, self-calibration, and wireless data transmission. The capacities of the iCapsuleEC were demonstrated not only for in situ measurement of ion concentrations but also for the optimization of the sensing electrodes. We also explored the possibility of the system for use in detection in simulated cell culture media.

An automated, fully-integrated nucleic acid analyzer based on microfluidic liquid handling robot technique.

On-site nucleic acid testing (NAT) plays an important role for disease monitoring and pathogen diagnosis. In this work, we developed an automated and fully-integrated nucleic acid analyzer by combining the automated liquid handling robot technique with the microfluidic droplet-based real-time PCR assay technique. The present analyzer could achieve multiple operations including sample introduction, nucleic acid extraction based on magnetic solid-phase extraction, reverse transcription and, sample droplet generation, PCR amplification, real-time and dual fluorescence detection of droplet array. A strategy of constructing an integrated compact and low-cost system was adopted to minimize the analyzer size to 50 × 45 × 45 cm (length × width × height), and reduce the instrument cost to ca. $900 with a single analysis cost less than $5. A simple chip was also designed to pre-load reagents and carry oil-covered PCR reaction droplets. We applied the analyzer to identify eight types of influenza pathogens in human throat swabs, and the results were consistent with the colloidal gold method.

Simultaneous deep transcriptome and proteome profiling in a single mouse oocyte.

Although single-cell multi-omics technologies are undergoing rapid development, simultaneous transcriptome and proteome analysis of a single-cell individual still faces great challenges. Here, we developed a single-cell simultaneous transcriptome and proteome (scSTAP) analysis platform based on microfluidics, high-throughput sequencing, and mass spectrometry technology to achieve deep and joint quantitative analysis of transcriptome and proteome at the single-cell level, providing an important resource for understanding the relationship between transcription and translation in cells. This platform was applied to analyze single mouse oocytes at different meiotic maturation stages, reaching an average quantification depth of 19,948 genes and 2,663 protein groups in single mouse oocytes. In particular, we analyzed the correlation of individual RNA and protein pairs, as well as the meiosis regulatory network with unprecedented depth, and identified 30 transcript-protein pairs as specific oocyte maturational signatures, which could be productive for exploring transcriptional and translational regulatory features during oocyte meiosis.

Model oxide-supported metal catalysts--comparison of ultrahigh vacuum and solution based preparation of Pd nanoparticles on a single-crystalline oxide substrate.

Using single-crystalline Fe(3)O(4)(111) films grown over Pt(111) in UHV as a model-support, we have characterized the nucleation behaviour and chemical properties of Pd particles grown over the film using different deposition techniques with scanning tunnelling microscopy and X-ray photoelectron spectroscopy. Comparison of Pd/Fe(3)O(4) samples created via Pd evaporation under UHV conditions and those resulting from the solution deposition of Pd-hydroxo complexes reveals that changes in the interfacial functionalization of such samples (i.e. roughening and hydroxylation) govern the differences in Pd nucleation behavior observed over pristine oxides relative to those exposed to alkaline solutions. Furthermore, it appears that other differences in the nature of the Pd precursor state (i.e. gas-phase Pd in UHV vs. [Pd(OH)(2)](n) aqueous complexes) play a negligible role in Pd nucleation and growth behaviour at elevated temperatures in UHV, suggesting facile decomposition of the Pd complexes deposited from the liquid phase. Applying temperature programmed desorption and infrared spectroscopy to probe the CO chemisorption properties of such samples after reduction in different reagents (CO, H(2)) shows the formation of bimetallic PdFe alloys following reduction in H(2), but monometallic Pd particles after CO reduction.

[In-situ monitoring algorithm of gases poisonous elements concentration with ultraviolet optical absorption spectroscopy based on recursion iterative method].

The key and challenge problem of in-situ monitoring poisonous elements of gases is how to separate the various gases absorption signal from mixed gases absorption spectroscopy and compute it's accuracy concentration? Here we present a new algorithms in return recursion iteration based on Lambert-Beer principle. In the algorithms, recurred by the character of absorption peak of various gases in the band of 190-290 nm UV rays continuous spectroscopy and the character of twin element fold for absorbance are used. Firstly, the authors suppose that there is no absorption for others gases in the character absorption band for a certain gas, the authors can inference the initial concentration of the gas. Then the authors switch to another character spectroscopy, and put the photons that gases absorption out of the total number of absorbed photons that are measured. So we could get the initial concentration of another gas. By analogy the authros can get the initial concentration of all kinds of other poisonous elements. Then come back to the character spectroscopy of the first gas, the authors can get a new concentration of the first gas from the difference between the total number of absorbed photons and the photons that other gases absorption. By analogy the authors can get the iterative concentration of other gases, by irterating this process repeatly for some times until the measurement error of the adjacent gas concentration is smaller than a certain numerical value. Finally the authors can get the real and accurate concentration of all kinds of gases. Experiment shows that the authors can get the accurate concentration of all kinds of gases with the algorithm. The accuracy can be within 2%, and at the same time, it is easy enough to satisfy the necessity of real-time requirement. In addition it could be used to measure the concentration of many kinds of gas at a time. It is robust and suitable to be taken into practice.

Optimization of Electrode Patterns for an ITO-Based Digital Microfluidic through the Finite Element Simulation.

Indium tin oxide (ITO)-based digital microfluidics (DMF) with unique optical and electrical properties are promising in the development of integrated, automatic and portable analytical systems. The fabrication technique using laser direct etching (LDE) on ITO glass has the advantages of being rapid, low cost and convenient. However, the fabrication resolution of LDE limits the minimum line width for patterns on ITO glasses, leading to a related wider lead wire for the actuating electrodes of DMF compared with photolithography. Therefore, the lead wire of electrodes could affect the droplet motion on the digital microfluidic chip due to the increased contact line with the droplet. Herein, we developed a finite element model of a DMF with improved efficiency to investigate the effect of the lead wire. An optimized electrode pattern was then designed based on a theoretical analysis and validated by a simulation, which significantly decreased the deformation of the droplets down to 0.012 mm. The performance of the optimized electrode was also verified in an experiment. The proposed simulation method could be further extended to other DMF systems or applications to provide an efficient approach for the design and optimization of DMF chips.