Zhenqing Li

University of Shanghai for Science and Technology | USST · School of Optical-Electrial and Computer Engineering

Pulsed field capillary electrophoresis (PFCE) is a predominant technique to cope with difficulties in resolving large DNA strands, yet it is still unclear whether pulsed electric field is effective for the separation of higher mass RNA. In this paper we focused on the role of pulsed electric field in large RNA fragments analysis by comparing RNA se...

This study reports improved pulsed field capillary electrophoresis (PFCE) for separation of large DNA ladders. Important analytical conditions, including gel polymer concentration, ratio of forward to backward pulse duration, and separation potential, were investigated for their effects on the separation performance of DNA ranging in size from 0.1...

Based on our previous work of in-capillary denaturing polymer electrophoresis, we present a study of RNA molecular separation up to 6.0 kilo nucleotide by pulsed field CE. This is the first systematic investigation of electrophoresis of a larger molecular mass RNA in linear hydroxyethylcellulose (HEC) under pulsed field conditions. The parameters t...

DNA fragments (0.1-10 kbp (kbp, kilo base pair)) separation by square-wave pulsed field CE in hydroxyethylcellulose (HEC, 1300 K) polymer was performed in this work. The effects of polymer concentration, pulse field strength, pulse frequency and modulation depth were investigated. We found that low HEC (about 0.1%) concentration is suitable for the...

Background: Rapid diagnosis of harmful microorganisms demonstrated its great importance for social health. Continuous flow PCR (CF-PCR) can realize rapid amplification of target genes by placing the microfluidic chip on heaters with different temperature. However, bubbles and evaporation always arise from heating, which makes the amplification not...

Capillary electrophoresis (CE) is a versatile analytical separation method in the field of biochemistry. Although it has been proved that the relative molecular mass (Mr) of the polymers determines the threshold concentration of the entangled polymer solution, which will affect the separation performance of DNA molecules, there is still no report o...

The concept of time to place conversion makes using a continuous flow polymerase chain reaction (CF-PCR) microfluidic chip an ideal way to reduce the time required for amplification of target genes; however, it also brings about low throughput amplicons. Although multiplex PCR can simultaneously amplify more than one target gene in the chip, it may...

Background Capillary electrophoresis (CE) is an effective method for protein analysis. Although previous researchers have proved that the separation performance of large DNA molecules was improved by pulsed field capillary electrophoresis (PFCE), there is lack of research about proteins separation by PFCE. Methods Herein, we systematically investi...

Droplet digital polymerase chain reaction (ddPCR) is an effective technique, with unparalleled sensitivity, for the absolute quantification of target nucleic acids. However, current commercial ddPCR devices for detecting the gene chip are time consuming due to complex image stitching. To address this issue, we propose a universal concentration dete...

Porphyromonas gingivalis (P.g), Treponema denticola (T.d), and Tannerella forsythia (T.f) are believed to be the major periodontal pathogens that cause gingivitis, which affects 50-90% of adults worldwide. Microfluidic chips based on continuous flow PCR (CF-PCR) are an ideal alternative to a traditional thermal cycler, because it can effectively re...

Capillary gel electrophoresis is widely applied for determination of sequence and size of DNA, in which the sieving gel plays an unignorable role. Herein, a pore-size controllable hydrogel was synthesized in the capillary with two symmetrical tetrahedron-like macromonomers consisting of pentaerythritoltetra (succinimidylcarboxypentyl) polyoxyethyle...

Based on differential pulse voltammetry technology, we developed a portable and affordable instrument for on-site detection of trace heavy metal pollutants in liquid through a disposable plastic pipette. It mainly consists of a six-electrode electrochemical sensor which is integrated in the instrument. The pipette chip is equipped with a pump valve...

The unprecedented global COVID‐19 pandemic strongly argues the critical need for innovative diagnostic tools meeting the requirement of test speed, accuracy, and throughput. Owing to the integration of optics and microfluidics technologies, optofluidic technology enables highly precise flow manipulation and highly sensitive signal detection at the...

The measurement of DNA concentration is an important step in many research procedures in molecular biology. Traditional method for DNA concentration determination is based on ultraviolet absorbance which suffers from low sensitivity. Thus, we proposed a high throughput and low-cost DNA concentration system based on fluorescence technology. We analy...

Fluorescent microspheres (FMs) are widely employed in diagnostics and life sciences research; here, we investigated the effect of capillary coating, polymer concentration, electric field strength, and sample concentration on the separation performance of 1.0 μm FMs in hydroxyethyl cellulose (HEC) by capillary electrophoresis (CE). Results showed th...

Front Cover: In article number 1900385 by Dawei Zhang, Yoshinori Yamaguchi, and co‐workers, a homogeneous tetra‐PEG polymer network is synthesized in a capillary. The results show that the separation performance in both slab‐gel electrophoresis and capillary electrophoresis is dramatically improved by tetra‐PEG. Single monoprotic ssDNA is also succ...

The reasons for restricting continuous flow polymerase chain reaction (CF-PCR) microfluidic chip from lab to application are that it is not portable and requires costly external precision pumps for sample injection. Herein, we employed water as the substitute for PCR solution, and investigated the effect of the cross-section, width-to-depth ratio,...

Although DNAs with single‐nucleotide difference (e.g., 1000 and 1001 nt) can be resolved by capillary electrophoresis (CE), separation of the same length DNA with single‐nucleotide difference is still a great challenge, which is caused by the structural or thermodynamical fluctuation of the sieving matrix. Here, a homogeneous tetra‐arm poly (ethyle...

Current continuous flow polymerase chain reaction (CF-PCR) microfluidic chip requires external precision syringe pump and off-line methods (e.g., electrophoresis, hybridization) to detect the PCR products, resulting in complex operations and possible cross-contamination, and consequently CF-PCR is still confined to the laboratories. Herein, a porta...

A rapid and cost-effective method for fabricating mini lens arrays is proposed. The lenses are made of silicone oil droplets and filled inside a polydimethylsiloxane (PDMS) elastomer. The lens arrays of different initial focal lengths and apertures can be fabricated by using the droplets of different volumes. Due to good elastic behavior of PDMS, t...

Effective separation of short DNA fragments is important for the identification of PCR or LAMP products. We investigated the effect of electric field strength, sample plug width, effective length of the capillary, concentration and molecular weight of polymer on the separation performance of small DNA. Results demonstrated that the sample plug play...

The mitochondria are referred to as the ‘power houses’ of the cell. The number of mitochondria is considered to be related to various diseases (e.g., obesity, degenerative diseases, and aging), and thus counting the number of mitochondria in per cell is helpful for the elucidation of the rare cells. Here, we report a mitochondria-aligning system th...

Slab gel electrophoresis (SGE) is the most common method for the separation of DNA fragments; thus, it is broadly applied to the field of biology and others. However, the traditional SGE protocol is quite tedious, and the experiment takes a long time. Moreover, the chemical consumption in SGE experiments is very high. This work proposes a simple me...

Rapid, low cost, and portable polymerase chain reaction system (PCR) can advance the diagnosis of infectious disease, especially for the third-world countries. Herein, we developed a compact PCR system based on Rayleigh–Bénard convection (RB-PCR). The optimal geometry parameters of the RB-PCR cell was obtained by finite element analysis. The amplif...

An integrated polymerase chain reaction (PCR) and capillary electrophoresis (CE) system can realize accurate quantification of the target PCR product by adding labeling dyes to the PCR reagents, because CE can discriminate all the subsequent nucleic acids, including the primers, non-specific and specific PCR products. Here we discuss the inhibition...

Recent research demonstrates that large numbers of long noncoding RNAs (lncRNAs) in mammals exhibit indices of functionality, and thus analysis of longer RNAs is of great significance. In the present work, we investigated the effect of molecular weight on the separation performance of long RNA by capillary electrophoresis (CE). Results demonstrate...

Capillary polymer electrophoresis is identified as a promising technology for the analysis of DNA from bacteria, virus and cells samples. In this paper, we proposed an innovative capillary polymer electrophoresis protocol for the quantification of polymerase chain reaction products. The internal standard method was modified and applied to capillary...

The analysis of small interfering RNA (siRNA) is important for gene function studies and drug developments. We employed capillary electrophoresis (CE) to study the separation of siRNA ladder marker, which were 10 double-stranded RNA (dsRNA) fragments ranged from 20 bp to 1000 bp, in solutions of hydroxyethylcellulose (HEC) polymer with different co...

The selection of sieving polymer for RNA fragments separation by capillary electrophoresis is imperative. We investigated the separation of RNA fragments ranged from 100 to 10,000 nt in polyethylene glycol (PEG) and polyethylene oxide (PEO) solutions with different molecular weight and different concentration. We found that the separation performan...

Ternary compound Cu2SnS3 (CTS) was fabricated by spray pyrolysis method. The influences of Cu precursor concentration and substrate temperature on the properties of the prepared films were investigated in detail. X-ray diffraction spectrometer & Raman spectra, energy dispersive spectroscopy, UV-Vis spectrophotometry, Four-probe Resistivity Tester a...

Periodontitis is a prevalent inflammatory disease caused by different species of anaerobic bacteria, e.g., Porphyromonas gingivalis (P.g), Treponema denticola (T.d), and Tannerella forsythia (T.f). We compared the separation result of DNA ladders in hydroxyethyl cellulose, poly(ethyleneoxide) (PEO) and polyethylene glycol, and analyzed the effect o...

Capillary electrophoresis (CE) was widely employed for the separation of nucleic acids or protein, but it was rarely applied in the quantification of Escherichia coli (E. coli). Here, we have analysed E. coli by CE with mercury lamp induced fluorescence, and demonstrated the relationship between its fluorescence intensity with the concentration of...

Gingivitis is a highly prevalent periodontal disease around the worldwide. Porphyromonas gingivalis (P.g), Treponema denticola (T.d) and Tannerela forsythia (T.f) were considered to be three important periodontal pathogens related to gingivitis, and research shows that the counts of periodontal pathogen cells in the patients before, during, and aft...

Photovoltaic property of Cu4SnS4 (CTS) is studied by employing a superstrate solar cell structure of Mo/CTS/In2S3/TiO2/fluorine-doped tin oxide (FTO) glass for the first time. The CTS absorber layer was prepared by a combination of mechanochemical and doctor blade processes. The annealing effects on the structural, optical and electronic properties...

We carried out capillary electrophoresis of 0.1-10.0 kilo base pair DNA fragments in a mixed hydroxyethyl cellulose (HEC) polymer. The mixed HEC polymer was prepared with different molecular weights (M-w) (90k, 250k, 720k and 1300k). The effects of important parameters, including the ratio of the mixture composition and the concentration of the mix...

Using hydroxyethylcellulose (HEC) solution as polymer matrix, this work systematically studied the separation performance of 100 base pairs (bp) DNA ladder (100 similar to 1500 bp) by direct current electric field capillary electrophoresis (CE). In the present paper, we systematically investigated the influence of polymer concentration and molecula...

The non-vacuum printing technology is studied for the fabrication of CuInSe 2 (CISe) thin film solar cell. CISe precursor powder, synthesized by the mechanochemical method, is dispersed by ethyl-cellulose to prepare screen-printing paste. The CISe paste is deposited on substrate by the screen-printing technology to form the CISe absorber layer. The...

DNA fragments ranging in size from 0.1 to 10.0 kbp were separated by constant electric field, square-wave pulsed electric field, and inversion pulsed electric field in hydroxyethylcellulose (HEC, 1300 K) polymer. The influence of electric field modes on the separation performance of DNA fragments was investigated when the modulation depth of pulsed...

The doctor-blade method is investigated for the preparation of Cu2ZnSnS4 films for low-cost solar cell application. Cu2ZnSnS4 precursor powder, the main raw material for the doctor-blade paste, is synthesized by a simple ball-milling process. The doctor-bladed Cu2ZnSnS4 films are annealed in N2 ambient under various conditions and characterized by...

A novel ethyl cellulose/CuInSe2 (CISe) composite light absorber layer and its photovoltaic effect are reported. The precursor absorber layer was deposited from screen printing paste containing ethyl cellulose and CISe powder, and was followed by rapid thermal annealing. Experimental results indicated that the ethyl cellulose remained in the anneale...

Geometric, electronic and vibrational properties of the most stable and energetically favourable configurations of indium oxide clusters InmOn (1 ≤ m, n ≤ 4) are investigated using density functional theory. The lowest energy geometries prefer the planar arrangement of the constituent atoms with a trend to maximize the number of ionic In—O bonds. D...

36 transmittance spectra of pasteurized milk are tested by a FT-IR-Spectrometer (Nicolet Nexus 870). In order to find the most informative region, three improved partial-least squares regression methods, including interval partial-least square regression method (iPLS), moving widow partial-least square regression method (MWPLSR) and changeable size...