JOURNAL OF FOOD PROCESS ENGINEERING
·
2018
·Vol. 42
·期 2
·e12976
·
IF 1.955
Ning Yang,Liang-Liang Xie,Chen Pan,Min-Feng Yuan,Zhi-Han Tao,Han-Ping Mao
Ubiquitous food security control is desirable. However, the analysis methods, such as those for milk, are highly based on manual analysis, leading to low efficiency. Thus, we report a multilayer paper-based microfluidic chip transforming chromatic readout to electric signals. First, colloidal gold immunochromatographic assays (GICA) are used to achieve the colorimetric occurrence. Secondly, the test (T) lines and control (C) lines are patterned to encode different EAN-8 barcode. Furthermore, accurate scanning is accomplished by the automatic threshold segmentation. These technologies make the digital determination of melamine (MEL) and chloramphenicol (CAP) by phone readily accessible. Results indicate that the accurate machine-scanning can be assured when MEL and CAP is above 30 ng/mL and 6 ng/mL in milk respectively. The detection time is under 8 min, and the stable storage life is over 90 days. Therefore, this simple chip allows rapid, machine-readable, electric-recordable diagnostic directly from chromatic assays with satisfying stability, specificity and accuracy. Practical applications This article illustrates a method used to determine the concentration of melamine and chloramphenicol in milk. When melamine and chloramphenicol is above 30 and 6 ng/ml in milk, the produced EAN-8 barcode can be recognized with high accurate level, compared with international standards, the results are acceptable and sensitive. This method is highly intellectual and environmentally friendly, with the disposable materials and instant smartphone-readable EAN-8 results patterns. This article demonstrates a multilayer paper chip based on EAN-8 encoding rules, colloidal gold nanoparticles, and immunochromatographic assays. The EAN-8 format assay is achieved by color-development occurrence of colloidal GICA in different encoding areas of EAN-8 code, and the analysis device, namely smartphone, is accessible by almost every individual. Therefore, this chip can pave a potential way for massive health control and digital automated analysis for daily life and industrial manufacture.
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MICROCHIMICA ACTA
·
2018
·Vol. 185
·期 8
·1-8
·
IF 5.705
Wen Dongxiao,He Minhui,Ma Kefeng,Cui Ying,Kong Jinming,Yang Huaixia,Liu Qingyun
The article describes an on-chip amplification scheme initiated by a terminal deoxynucleotidyl transferase (TdT) for highly sensitive fluorometric determination of protein. Two thrombin-binding aptamers were designed to capture thrombin as they can form a sandwich structure for improved specificity. An amino-modified aptamer (TBA29) was first immobilized on a silicon chip. After capture of thrombin, a second aptamer (TBA15) was conjugated to the second binding site of thrombin. The 3’-terminal of aptamer TBA15 is exposed on the chip surface, and then fluorescein-labeled 12-dATP associates to the 3’-terminal with the help of TdT. This results in signal amplification, and eventually leads to highly sensitive detection. Under optimal conditions, fluorescence intensity is linearly related to the logarithm of thrombin concentration in the range of 100 fM - 0.1 μM, and the detection limit is as low as 2.0 fM. The assay is sensitive and selective even over potentially interfering proteins and in the presence of human serum.
Schematic strategy for thrombin detection. Two thrombin-binding aptamers were designed to capture thrombin to form a sandwich structure for improved specificity. The protein detection is based on TdT initiated on-chip fluorescent amplification.
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SENSORS
·
2018
·Vol. 18
·期 11
·4002
·
IF 2.475
Feiyi Wu,Min Wang
Recently, smartphone-based chromogenic sensing with paper-based microfluidic technology has played an increasingly important role in biochemical assays. However, generally there were three defects: (i) the paper-based chips still required complicated fabrication, and the hydrophobic boundaries on the chips were not clear enough; (ii) the chromogenic signals could not be steadily captured; (iii) the smartphone apps were restricted to the detection of specific target analytes and could not be extended for different assays unless reprogrammed. To solve these problems, in this study, a portable smartphone-based sensing system with a 3D-printed chip was developed. A 3D-printed imaging platform was designed to significantly reduce sensing errors generated during signal capture, and a brand-new strategy for signal processing in downloadable apps was established. As a proof-of-concept, the system was applied for detection of organophosphorus pesticides and multi-assay of fruit juice, showing excellent sensing performance. For different target analytes, the most efficient color channel could be selected for signal analysis, and the calibration equation could be directly set in user interface rather than programming environment, thus the developed system could be flexibly extended for other biochemical assays. Consequently, this study provides a novel methodology for smartphone-based biochemical sensing.Keywords:smartphone;sensing system;chromogenic;signal capture;signal processing;organophosphorus pesticides;multi-assay;fruit juice
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JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
·
2016
·Vol. 31
·期 7
·1391-1399
·
IF 3.379
Jing Zhang,Beibei Chen,Han Wang,Xi Huang,Man He,Bin Hu
Microfluidic devices provide a potential platform that can specialize in miniaturization, integration and automation. In this study, we prepared ethanediamine modified poly glycidyl methacrylate trimethylol propane triacrylate monolithic columns (poly (GMA-co-TRIM-NH2)) in a microfluidic chip channel and established a novel method by combining chip-based poly (GMA-co-TRIM-NH2) monolithic microextraction with inductively coupled plasma mass spectrometry (ICP-MS) for the determination of bismuth in cell samples. Various factors affecting chip-based monolithic microextraction of bismuth were investigated. Under the optimized conditions, the limit of detection was 0.21 ng mL−1 and the relative standard deviation for bismuth was 6.0% (c = 5 ng mL−1, n = 7). The method was successfully applied to the analysis of HepG2 cells incubated with bismuth. With consumption of ∼600 cells, the average amount of bismuth was determined to be at the sub picogram level in a single cell. The prepared chip-based poly (GMA-co-TRIM-NH2) monolithic column had a high-surface area and exhibited high extraction efficiency towards bismuth. The proposed chip-based monolithic microextraction method combined with ICP-MS provides a novel strategy for the analysis of trace metals in cells.
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ANALYTICAL SCIENCES
·
2017
·Vol. 33
·期 4
·481-486
·
IF 1.228
Juan WU,Yanbin JIANG,Lishi WANG,Qiang ZENG
In order to confirm the correlation between interfacial properties of modified surface plasmon resonance (SPR) chips and their SPR responses to immobilized anti-IgG, SPR chips were modified by mercaptoundecanoic acid, poly(ethylene glycol) diacrylate (PEG), PEG-based copolymer and cyclodextrin coupled PEG using self-assembled or radical polymerization methods. The resulting interfacial properties such as film thickness and hydrophilicity were characterized by AFM, elliptic polarization scanners and contact angle meter. Immobilization of human IgG on the modified chips was achieved by EDC/NHS activation through an amide bond. The association between fixed IgG and free anti-IgG was reflected by the variation of SPR responses and the binding ability was evaluated by Langmuir isotherms. As observed, the adsorption between IgG and anti-IgG was affected by the interfacial properties of different modifiers, such that a chip with a thinner and more hydrophilic layer may result in a higher SPR response, producing a larger adsorption equilibrium constant for protein interaction.
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ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2017
·Vol. 25
·期 26
·25629-25637
·
IF 2.741
Yi Shengze,Sun Yuanyuan,Hu Xin,Xu Hongxia,Gao Bin,Wu Jichun
The adsorption removal of levofloxacin (LEV), a widely used fluoroquinolone antibiotic, by using the biochars derived from the pyrolysis of pine wood chip pretreated with cerium trichloride was investigated through batch sorption experiments and multiple characterization techniques. The differences in the basic physicochemical properties between Ce-impregnated biochars and the pristine biochars were confirmed by the analysis of elemental compositions, specific surface areas, energy dispersive spectrometry, X-ray diffraction, and thermo-gravimetry. FT-IR spectra of the pre- and post-sorption biochars confirmed the chemical adsorption for LEV sorption onto the biochars. Large shifts in the binding energy of Ce 3d , O 1s , C 1s , and N 1s regions on the pre- and post-sorption biochars indicated the surface complexation of LEV molecule onto the biochars. The binding species of Ce 4+ and Ce 3+ identified by X-ray photoelectron spectroscopy reflect the role of Ce oxides during sorption. Batch adsorption showed the significant enhancement of adsorption capacity for LEV after the Ce modification. Batch adsorption kinetic data fitted well with the pseudo-second-order model. Both the Langmuir and the Freundlich models reproduced the isotherm data well. Findings from this work indicated that Ce-impregnated biochars can be effective for the removal of aqueous LEV.
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JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2024
·
IF 5.7
Li Wang,Wanwan Wang,Shumin Zhang,Jie Wei,Qingmin Chen,Tianhui Jiao,Anhui Lin,Quansheng Chen,Xiao-Mei Chen
In this study, we present an intelligent electromagnetic-actuated microfluidic chip integrated with a G-quadruplex DNAzyme-based biocatalysis platform for rapid and sensitive tetracycline (TC) detection. In this sensing system, TC significantly quenches fluorescent magnetic carbon dots (M-CDs) via the internal filtration effect and dynamic quenching (the excitation and emission wavelength at 350 and 440 nm, respectively). Then, the G-quadruplex on the M-CDs-Aptamer is exposed and bound with hemin to form hemin-G-quadruplex DNAzyme, catalyzing the conversion of 3,3′,5,5′-tetramethylbenzidine to produce blue color. This enables the fluorescence/colorimetric detection of TC. Importantly, an automatic electromagnet-integrated microfluidic chip was designed to control the shuttling of magnetic materials in each function slot according to a programmed sequence. Under the optimal conditions, the detection limits of TC for fluorescence and colorimetric methods were 11 and 43 μmol/L, respectively. The detection results for tilapia (Oreochromis nilotica) were comparable to those of traditional high-performance liquid chromatography. This platform offers excellent performance for TC determination and potential for portable, intelligent detection of trace pollutants in food and the environment.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Jiaxue Liang,Hang Qi,Feng Zhu,Shuqi Chen,Bohua Liu,Chongling Sun,Yanyan Wang
Real-time monitoring the drugs penetration into brain is crucial for clinical therapy of neurodegenerative diseases. In this study, a Blood-Brain Barrier-electrochemical sensing (BBB-ES) platform combining BBB on chip model and electrochemical sensing system was proposed, which facilitated stable BBB growth under fluidic conditions and realized real-time detection of L-Dopa across the BBB. Based on this system, the effects of fluid force on the cell morphology, skeleton arrangement and tight junction protein ZO-1 of BBB growth were evaluated, it was verified that the fluid force promote cell rearrangement. Additionally, L-Dopa detecting performance was optimized by modifying SWNTs-AuNPs-PPy/Tyr(Single-Walled Carbon Nanotubes-Au Nanoparticles-Polypyrrole/Tyrosinase) on electrochemical electrode, which showed a wide linear response range of 10–500 μM and excellent selectivity toward L-Dopa. The integrated BBB-ES system was finally applied to real-time monitor the penetration process of L-Dopa through the BBB, it was proved that the penetration of L-Dopa increased with the increase of flow rate and time, and finding that L-Dopa was delivered by passive diffusion without disrupting the integrity of BBB. Based on these findings, the system can be used to monitor the real-time process of different drugs penetrating BBB and even different organ barriers, which also provide the possibility to solve the clinical demand for drugs screen.
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ACS Nano
·
2024
·
IF 15.8
Yudong Lan,Yiwen Wang,Yu Wang,Guiling Lu,Ling Liu,Tao Tang,Ming Li,Yong Cheng,Jianrong Xiao,Xinyu Li
For practical application of lithium–sulfur batteries (LSBs), designing devices with an overall optimal structure instead of modifying electrode materials is significant. Herein, we report a chip-inspired design of a vertically integrated structure as an LSB cathode by implanting Mo2C nanoparticles and nanosulfur into the reduced graphene oxide (rGO) matrix. This configuration enabled the synthesis of isolated sulfur nanoreactors (S-NRs) integrated in a tandem array on the rGO, generating chip-like integrated LSBs. The spatial confinement/protection and concentration gradient of the S-NRs effectively avoided the dissolution, diffusion, and loss of polysulfides, thereby enhancing the sulfur utilization and redox reaction kinetics. Additionally, the adaptive storage energy can be improved by utilizing the tandem, isolation, and synergistic multiplicative effect among the nanoreactor units. As a result, the integrated LSB cathode obtained excellent electrochemical performances with an initial capacity of 1392 mAh g–1 at 0.1C, a low capacity decay rate of 0.017% per cycle during 1500 cycles of operation at 0.5C, and a superior rate performance. This work provides a rational design idea and method of further advancing the precise preparation of high-performance energy storage devices.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2024
·
IF 8
Qiudi Xu,Ke Liu,Yu He,Lan Wang,Zefan Lu,Zhongxuan Liu,Tao Zhang
Digital microfluidics (DMF), as an emerging liquid-handling technology, is widely recognized as an ideal platform for enzyme-linked immunosorbent assay (ELISA). However, current DMF-based ELISA methods are highly dependent on magnetic beads (MBs), which usually involves tedious modification of MBs, complex peripherals for MBs control, and impairs the parallel processing capability of DMF. To address these issues, we herein developed a photopatterned reactive sites-integrated DMF chip (PRS-DMF) for MBs-free immunoassay. By taking advantage of click chemistry between N-(allyloxycarbonyloxy) succinimide and thiol-ene substrate, the preparation of PRS is very simple, and leaves the reactive N-hydroxysuccinimide (NHS) ester groups on the surface. This enables direct biomolecules immobilization without any surface modification/activation processes. Moreover, the patterned micropillar array can notably increase the specific surface area, and promote the liquid mixing and immunoreaction. As a consequence, highly sensitive and MBs-free ELISA can be readily achieved on PRS-DMF, with a proof-of-concept H5N1 assay having been successfully demonstrated herein, which offers a low limit of detection (LOD) of 147 pg/mL. This also avoids the use of complex magnetic peripherals, and thus, contributing to the instrument miniaturization into a very compact form. It is therefore reasonably expected that the proposed PRS-DMF may serve as a promising platform for a variety of biological and biomedical applications, especially in the field of point-of-care testing (POCT).
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Chemosensors
·
2024
·Vol. 12
·期 10
·214
·
IF 3.7
Yun Hui,Weijun Kong,Weiliang Shu,Zhiting Peng,Fengshan Shen,Mingyang Jiang,Zhen Xu,Tianzhun Wu,Wenhua Zhou,Xue-Feng Yu
The measurement of cardiac troponin I (cTnI) is of vital importance for the early diagnosis of acute myocardial infarction. In this study, an enhanced electrochemiluminescent immunoassay for the highly sensitive and precise determination of cTnI was reported. A biomimetic chip with nepenthes peristome surface microstructures to achieve single-layer microbead arrays and integrated microelectrode arrays (MEAs) for ECL detection was microfabricated. Ru@SiO2nanoparticles were prepared as signal amplificators labeling immunomagnetic beads. Dendrimer-encapsulated platinum nanoparticles (Pt DENs) were electrochemically modified on ITO MEAs. The resulting Pt DEN-modified ITO MEAs preserved good optical transparency and exhibited an approximately 20-fold ECL signal amplification compared to that obtained from bare ITO. The method made full use of the biomimetic chip with Pt DENs to develop single-layer immunomagnetic bead arrays with increasingly catalyzed electrochemical oxidation of the [Ru(bpy)3]2+–TPA system. Consequently, a limit of detection calculated as 0.38 pg/mL (S/N = 3) was obtained with excellent selectivity, demonstrating significant potential for the detection of cTnI in clinical diagnostics.
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BIOMEDICAL MICRODEVICES
·
2024
·Vol. 26
·期 2
·1-9
·
IF 3
Li Zhenqing,Ma Xiaolu,Zhang Zhen,Wang Xiaoyang,Yang Bo,Yang Jing,Zeng Yuan,Yuan Xujun,Zhang Dawei,Yamaguchi Yoshinori
Polymerase chain reaction (PCR) has been considered as the gold standard for detecting nucleic acids. The simple PCR system is of great significance for medical applications in remote areas, especially for the developing countries. Herein, we proposed a low-cost self-assembled platform for microchamber PCR. The working principle is rotating the chamber PCR microfluidic chip between two heaters with fixed temperature to solve the problem of low temperature variation rate. The system consists of two temperature controllers, a screw slide rail, a chamber array microfluidic chip and a self-built software. Such a system can be constructed at a cost of about US$60. The micro chamber PCR can be finished by rotating the microfluidic chip between two heaters with fixed temperature. Results demonstrated that the sensitivity of the temperature controller is 0.1℃. The relative error of the duration for the microfluidic chip was 0.02 s. Finally, we successfully finished amplification of the target gene of Porphyromonas gingivalis in the chamber PCR microfluidic chip within 35 min and on-site detection of its PCR products by fluorescence. The chip consisted of 3200 cylindrical chambers. The volume of reagent in each volume is as low as 0.628 nL. This work provides an effective method to reduce the amplification time required for micro chamber PCR.
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