Electrophoresis Chip Research Articles

Indirect detection of lead(II), cadmium(II) and mercury(II) on a microfluidic electrophoresis chip.

Water environments contaminated by heavy metal ions present significant challenges because these pollutants do not degrade naturally, leading to their gradual bioaccumulation in animals and plants, which ultimately poses an insurmountable threat to human health. Therefore, rapid and accurate detection of heavy metal ions in water is of great significance for environmental protection and disease prevention. In this work, we developed a novel method based on microfluidic electrophoresis coupled with indirect chemiluminescence for the immediate detection of Cd(II), Pb(II) and Hg(II) heavy metal ions. The displacement of the Co(II) ions within the chemiluminescence mixture by the above migrating sample cations caused a measurable reduction in the background signal. The results showed that the detection limits of Cd(II), Pb(II) and Hg(II) ions under the best detection conditions were 5.83 × 10-8 M, 5.38 × 10-8 M and 2.09 × 10-8 M, respectively, which were 1-2 orders of magnitude lower than those of the indirect UV method and 1 order of magnitude lower than that of the indirect laser induced detection method. This method can provide a possibility for the rapid detection of multiple heavy metal ions in actual water environments.

Hydrodynamic injection for microchip electrophoresis: Development of an innovative passive system

The world is facing challenges in terms of environmental sustainability and rising costs. In this context, miniaturized equipment such as microfluidic devices can be used to manipulate small volumes of fluids in micrometer-sized channels incorporating multiple components such as pumps, valves and mixers. Due to their high flexibility, these devices can provide sustainable alternatives to traditional platforms. The present study focuses on the design of a user-friendly and reliable microfluidic capillary electrophoresis chip for pharmaceutical applications. To meet pharmaceutical requirements in terms of quantification performance and overcome the injection variability usually observed with such microfluidic systems, a reliable and reproducible design for hydrodynamic injection using passive valves has been developed. It has been successfully used for synthetic cathinone analysis.

Investigation of a microfluidic free-flow electrophoresis chip of glass substrate with integrated indium tin oxide electrodes

Free-flow electrophoresis (FFE) is a unique form of electrophoresis that allows continuous electrophoresis separation. Small scale FFE is very practical for processing of limited amounts of samples for analytical purposes. In this work, glass substrate was designed as a chip FFE and its performance was visually demonstrated and characterized using fluorescent probes. The chip consisted of two pieces of glass substrate. One of them was patterned with a planar indium tin oxide (ITO) electrodes, and the other glass was designed with inlets for sample infusion and electrolyte transfer. The depth of the separation channel (15 × 60 mm) is defined by a tape spacer of 85 μm. Since the integrated ITO electrodes in direct contact with the working solution in the separation channel, a voltage as high as 600 V can be applied without bubbling problems. The main operation factors such as buffer concentration, pH, voltage, and flow rate were optimized to separate the probes, and the results were compared with capillary electrophoresis. The role of EOF and electrolysis was also discussed. Compared to photolithographic wet etching, this design is easier to implement, and it enables effective FFE operation. This chip FFE system has potential application in processing and cell sorting.

HDL subfractions determined by microfluidic chip electrophoresis predict the vulnerability of intracranial plaque: A HRMRI study

AimHigh-density lipoprotein (HDL) can be divided into several subfractions based on density, size and composition. Accumulative evidence strongly suggests that the subfractions of HDL have very different roles in the pathogenesis of atherosclerosis. The purpose of this study was to further delineate the relationship between HDL subfractions extracted by microfluidic chip electrophoresis and the vulnerability of plaques in patients with intracranial atherosclerosis with a high-resolution magnetic resonance imaging (HRMRI) study. MethodsWe prospectively enrolled patients with single atherosclerotic plaque in the middle cerebral artery (MCA) or basilar artery (BA) between July 2020 and Dec 2022 and performed 3-tesla HRMRI on the relevant artery. The HDL cholesterol concentration and HDL subfractions (HDL-2a, HDL-2b and HDL-3) percentage were analyzed in serum samples from the same patients by electrophoresis on a microfluidics system. ResultsA total of 81 MCA or BA plaques [38 (46.9%) symptomatic and 43 (53.1%) asymptomatic] in 81 patients were identified on HRMRI. Patients with symptomatic plaques had a significantly lower HDL-2b level than asymptomatic plaques [symptomatic vs. asymptomatic: 0.16 (0.10–0.18) vs. 0.27(0.21–0.34), p = 0.001]. After adjusting for demographics and vascular risk factors, logistic regression showed that HDL-2b was inversely associated with asymptomatic plaques (B = −0.04, P = 0.017). According to receiver operating characteristic (ROC) curve model analysis, the cutoff point of HDL-2b in predicting asymptomatic plaques was 0.21 mmol/L (Area under curve: 0.719, specificity: 73.7%, sensitivity: 72.1%). Furthermore, plaque enhancement on HRMRI (P < 0.001), positive remodeling (P < 0.001), plaque load (P < 0.001) and luminal stenosis (P < 0.001) were superior among patients with HDL-2b < 0.21 mmol/L. ConclusionsOur data showed that serum HDL-2b levels may serve as a biomarker for predicting vulnerability in intracranial atherosclerotic plaques.

A universal dual-mode hydrogel array based on phage-DNA probe for simultaneous rapid screening and precisely quantitative detection of Escherichia coli O157:H7 in foods by the fluorescent/microfluidic chip electrophoresis methods

Rapid and specific detection of virulent bacterial strains is a great challenge for food safety regarding large amounts of contaminated samples. Herein, a dual-mode hydrogel array biosensor was constructed to simultaneously rapidly screen and precisely quantitatively detect virulent Escherichia coli O157:H7 (E. coli O157:H7) based on a novel DNA-modified phage probe. First, E. coli O157:H7 was incubated with alginate to form the E. coli O157:H7/hydrogel premix complex. Subsequently, hydrogel formation by cross-linking upon the addition of calcium ions and phages for E. coli O157:H7 modified with a DNA primer (phage-DNA) was added to the alginate hydrogel. The DNA on the complex could trigger rolling circle amplification (RCA) to form a phage probe containing a long-chain DNA skeleton (phage@RCA-DNA). The RCA-DNA was then hybridized with the complementary DNA (cDNA) to form double-stranded DNA fragments (phage@RCA-dsDNA), which could be stained by the SYBR Green dye to emit visual green fluorescence (FL) and determined by a smartphone for rapid screening. Meanwhile, the unreacted cDNA in the supernatant could be quantitatively detected by microfluidic chip electrophoresis (MCE). The signal decrement was also proportional to the bacterial concentration. The detection limit values of E. coli O157:H7 were 50 CFU mL−1 by the FL signal and 6 CFU mL−1 by the MCE signal. The two results could be mutually corrected to decrease the false-positive results. This assay was also employed to detect virulent Salmonella Typhimurium (S. Typhimurium) using the corresponding S. Typhimurium phage@RCA-DNA probe. All these results demonstrated that the universal bioassay was suitable for simultaneous rapid screening and precisely quantitative detection of virulent bacterial strains.

Decoding of exosome heterogeneity for cancer theranostics.

Extracellular Vesicles (EVs) discovery establishes a new milestone in cancer research. It explains cancer biology in a new way. EVs classified some significant subclasses such as macrovesicle (originated from plasma membrane), apoptotic bodies (originated from the plasma membrane and endoplasmic reticulum), and exosomes (originated from endosomes).1 The theranostic signature of exosomes in cancer healing is impressive, but its heterogeneity leads most complicated domain of research. Therefore we comment on decoding exosome heterogeneity for future efficiency and effective cancer theranostics development. EVs are the cell-secreted one of the most important entities. The exosome attracted much attention due to its versatile uses. Overall, its participation in intercellular communication and its inner cargos (DNA, RNA, proteins, lipids and glycan)2 can reprogram the recipient cells. In addition, it also shows the healthy or pathologic complication status of the parent cells. In cancer, tumor and exosomes interlink a complex chapter of cancer biology. Exosomes play an important role in accelerated tumor growth, immune cell reprogramming,2 angiogenesis,3 extracellular matrix remodelling,4, 5 metastasis,4, 5 epithelial-mesenchymal transition (EMT),4, 5 organ-specific metastasis,5, 6 drug resistance and cancer stem cell development.3, 4 Clinically aspect, the exosome is the source of the cancer biomarkers.7-9 Exosome heterogeneity1 is evolving into a major conflict in cancer biomarker and therapeutic research.10 The exosome heterogeneity (Figure 1) is based on several facts such as origin, size, quantity, and internal molecular diversity.1 Exosome size distribution is the most complicated side of tumor-derived exosomes (TEXs). Scientific evidence shows that the same cells release differently-sized exosomes. This size-oriented biodiversity is reflected in using different isolation methods.9, 10 The tumor cells release more exosomes compared to healthy cells. The higher release of exosomes from tumor cells depends on several factors, such as drug and therapeutic exposures, hypoxic conditions, and senescence. The functional diversity of exosomes is related to the surface molecular expression and inner cargos of exosomes. All these complicated/complex parameters lead to a challenging ecosystem development of exosome-based cancer theragnostics (combination of biomarkers and therapeutics research). This scenario requires a solution to solve these challenges. Based on several innovative nano platform-based approaches transform these challenges into an opportunity for exosome researcher in a detailed exploration of exosome.11 Exosomes isolation, size and quantity related complication solved via microfluidic device, fluorescence antibody based exosome tracking, Nanoparticle tracking analysis (NTA) (above 60 nm exosome size challenging for its application),12, 13 magnetic and surface plasma resonance principle based single exosome screening,1 advanced sensitive flow cytometry (it is capable of the separation of exosome subpopulation) and electrophoresis chip. Molecular profiling of exosomes is one of the most critical tasks revealing the functional diversity of bioactive cargo molecules of exosomes. Droplet digital polymerase chain reaction (it is sensitive to the detection of rear mutations in tumor-derived exosomes),1 microfluidic technology combined with a chip system, and an electrochemical principle-based micro RNA profiling of exosomes explain the cancer complication of a new dimension.1 The downstream process of exosome profiling needs a muti-omics approach for proper molecular diversity to understand.1 The single cells exosome profiling approach combines with machine learning for more precision cancer marker development.14 All these technological advancements support constructing the next-generation promising cancer theranostic era based on exosomes.15, 16 Finally, decoding exosome heterogeneity opens a new door for exosome-based precision medicine17 and vaccines18 for cancer. We hope this article encourages large-scale EV research to explore a single exosome profiling approach and future exosome-based cancer precision medicine development. Not applicable. The authors declare no conflict of interest. There is no funding for this study.

Impact of Microfluidic Chip Electrophoresis in Modern Analysis: An Update on Recent Trends

Abstract: The recent development of microfluidics and lab-on-a-chip technology has substantially raised interest in analytical chemistry. Since, they have demonstrated to be extraordinarily adept at precise fluid control, cell manipulation, and signal output, microfluidic chips are a useful tool for quick and in-depth single-cell investigation. This technique is cost-effective, less time-consuming, automatic, high mobility, and fast separation technique. Due to the internal chip sizes, which range from micrometers to millimeters, consumption of the samples and reagents occurs at the nanoliter and picoliter levels. The microfluidic device can fit a variety of functions onto a few centimeter-long chips. In this article, we discussed numerous preparations of microfluidic chip electrophoresis and its recent advancements. This method is useful for the detection of various small amounts of content with less time and greater efficacy. It is also useful in cancer studies, 3D inkjet printing, immunoassay investigation in cell-cell interactions, analysis of nanoparticles, dielectrophoretic particle separation, plant alkaloids, and forensic science applications. This review, therefore, examines the use of various microfluidic chips in electrophoretic separation during 2017–2022. There are various papers found by search, indicating continuous activity in the research area along with studies to explain its material, method, and its efficacy.

Quadruple UV LED Array for Facile, Portable, and Online Intrinsic Fluorescent Imaging of Protein in a Whole Gel Electrophoresis Chip.

Intrinsic fluorescence imaging (IFI) has been used for the stain-free detection of proteins in slab gel. However, complicated detection setups and small irradiation area limited the development of facile, online, and portable imaging of the whole slab gel. We here designed a quadruple UV LED array to produce even and powerful area light for direct irradiation of gel electrophoresis chip (GEC) at 275 nm. In addition, we only used a filter of 365 nm, a UV camera lens, and a CCD for IFI detection. We integrated the simple detection setup with the small GEC to construct the IFI-GEC device with a portable size of 15 × 15 × 38 cm. We detected three model proteins to demonstrate the good evenness of the LED array and the online imaging of the whole GEC. Furthermore, the reproducible IFI-GEC detection was completed within 10 min and the LOD was as low as 40 ng for lysozyme detection. All results indicated the potential of the IFI-GEC device for online and portable detection of proteins without staining.

Application of microfluidic chip electrophoresis for high-throughput nucleic acid fluorescence fragment analysis assays.

Nucleic acid fragment analysis via separation and detection are routine operations in molecular biology. However, analysis of small single-stranded nucleic acid fragments (<100nt) is challenging and mainly limited to labor-intensive polyacrylamide gel electrophoresis or high-cost capillary electrophoresis methods. Here we report an alternative method, a microfluidic chip electrophoresis system that provides a size resolution of 5nt and a detection time of one minute per sample of fluorescence-labeled DNA/RNA fragments. The feasibility of this system was evaluated by quantifying CRISPR-Cas9 cleavage efficiency and the detection resolution was evaluated by analyzing ssDNA/RNA adenylation and phosphorylation. We employed this system to study the RNA capping efficiency and double-stranded DNA unwinding efficiency in isothermal amplification as two examples for assay design and evaluation. The microfluidic chip electrophoresis system provides a rapid, sensitive, and high-throughput fluorescence fragment analysis (FFA), and can be applied for enzyme characterization, reaction optimization, and product quality control in various molecular biology processes.

DNA-Directed Protein Anchoring on Oligo/Alkanethiol-Coated Gold Nanoparticles: A Versatile Platform for Biosensing Applications

Herein, we report on a smart biosensing platform that exploits gold nanoparticles (AuNPs) functionalized through ssDNA self-assembled monolayers (SAM) and the DNA-directed immobilization (DDI) of DNA-protein conjugates; a novel, high-sensitivity optical characterization technique based on a miniaturized gel electrophoresis chip integrated with online thermal lens spectrometry (MGEC-TLS), for the high-sensitivity detection of antigen binding events. Specifically, we characterized the physicochemical properties of 20 nm AuNPs covered with mixed SAMs of thiolated single-stranded DNA and bio-repellent molecules, referred to as top-terminated oligo-ethylene glycol (TOEG6), demonstrating high colloidal stability, optimal binder surface density, and proper hybridization capacity. Further, to explore the design in the frame of cancer-associated antigen detection, complementary ssDNA fragments conjugated with a nanobody, called C8, were loaded on the particles and employed to detect the presence of the HER2-ECD antigen in liquid. At variance with conventional surface plasmon resonance detection, MGEC-TLS characterization confirmed the capability of the assay to titrate the HER2-ECD antigen down to concentrations of 440 ng/mL. The high versatility of the directed protein-DNA conjugates immobilization through DNA hybridization on plasmonic scaffolds and coupled with the high sensitivity of the MGEC-TLS detection qualifies the proposed assay as a potential, easily operated biosensing strategy for the fast and label-free detection of disease-relevant antigens.

Voltage-induced concentration enhancement of analyte solutes in microfluidic chips

Microfluidic-based enrichment techniques have had a profound impact on chemistry, owing to their ability to improve the sensitivity of detection by increasing the concentration of analytes in minute fluid volumes. Herein, concentration enrichment of analyte solutes is achieved by using voltage assist in a microchip with two reservoirs. A numerical model is developed to describe the complex analyte focusing process, which to date has not been investigated before. Numerical computations are systematically conducted to study the influences of applied voltage, mass transfer coefficient, electrode location, reservoir diameter and number of mass transfer channels on the concentration enrichment in a designed Polydimethylsiloxane (PDMS)/Glass microfluidic electrophoresis chip. The electric fields, concentration distributions, and electrophoretic fluxes are obtained, which can reveal insightful enrichment mechanisms. It is found that the factors that can increase the electrophoretic flux in the mass transfer channel and enhance the electric field strength in the enrichment reservoir, such as moving the electrode back or increasing the number of mass transfer channels, are particularly important to improve the enrichment performance. The final microchip after considering the Joule heating effect has a 335-fold and 2.8-fold maximum and average concentration enrichments, respectively. Furthermore, this method is applied to the experimental enrichment of Rhodamine B and heavy metal cadmium (II) ions to test it performance.

An ultrasensitive bunge bedstraw herb type DNA machine for absolute quantification of mRNA in single cell

Messenger ribonucleic acids (mRNAs) comprise a class of small nucleic acids carrying genetic information, which exhibit very important role in medical research and diagnosis. If only the mean mRNA expression levels of the mRNA population are considered in medical research, important information linking mRNA expression and cellular function may be lost. Single-cell analysis provides valuable insights into studying its heterogeneity, signaling, and stochastic gene expression. In this study, a “bunge bedstraw herb”-type DNA machine based on DNAzyme catalyzing coupled clamping hybrid chain reaction (c-HCR) is presented. In the DNA machine, a bunge bedstraw herb-type DNA structure was first formed by hybridizing a core junction scaffold cruciform probe to a hairpin probe that can trigger the c-HCR via a target molecule in four directions. This approach can reduce the detection limit of mRNA to 5 × 10−15 M. Absolute quantification of survivin mRNA in individual cells was achieved using the DNA machine on a microfluidic chip electrophoresis platform. The reported method represents an unprecedented single-cell analysis platform for single-cell biology studies.

Development of high-resolution multidimensional native protein microfluidic chip electrophoresis fingerprinting and its application in the quick analysis of unknown microorganisms

The unascertained, constant mutation and emergence of new types of microorganisms present significant challenges to their detection. Differing from the focus on the limited local 16S rRNA gene or protein markers, characteristic whole fingerprint technologies at the omic level are particularly suitable for unknown analytes since accurate knowledge about the constituents is not necessarily required. Herein, through a combination of several innovative strategies, including pure water isotachophoresis integrated (2 + 1)D electrophoresis, inversion-funnel peak stacking channel geometry and COMSOL computer-aided fluid simulation, high-resolution whole protein 2D native microfluidic chip electrophoresis was achieved within less than 1 min. The highest ever reported peak capacity for native 2D chip electrophoresis was obtained. Furthermore, taking Escherichia coli, Staphylococcus aureus, and Bacillus subtilis as model analytes without protein biomarker information, the feasibility of the identification and semiqualification of unknown microbes in pure or mixed samples was explored with the utilisation of original algorithms, including SIFT feature abstraction and a global information entropy combined support vector machine. As such, the multidisciplinary cooperation in the present study demonstrates monstrated promising prospects for microfluidic chip electropherogram fingerprint-based quick microorganism assays, biointeraction studies, and drug screenings, even if the analytes are not fully ascertained.

A simple and reliable microfabrication process for a programmable microvalve array

We describe our reliable methodology for fabricating a complex programmable microvalve array (PMA) and its integration with a glass microcapillary electrophoresis chip. This methodology is applicable to any device that requires multilayered PDMS, multiple alignment processes, selective PDMS bonding, and multilayered integration with downstream sensing systems. Along with the detailed step-by-step process, we discuss essential quality assurance checks that can be performed throughout fabrication to assist in troubleshooting and maximizing chip yield.•Comprehensive instructions for designing and fabricating a programmable microvalve array.•Selective bonding of PDMS and glass by microcontact printing.•Numerous quality control procedures to boost chip yield.

Detection and separation of proteins using micro/nanofluidics devices.

Microfluidics is the technology or system wherein the behavior of fluids' is studied onto a miniaturized device composed of chambers and tunnels. In biological and biomedical sciences, microfluidic technology/system or device serves as an ultra-high-output approach capable of detecting and separating the biomolecules present even in trace quantities. Given the essential role of protein, the identification and quantification of proteins help understand the various living systems' biological function regulation. Microfluidics has enormous potential to enable biological investigation at the cellular and molecular level and maybe a fair substitution of the sophisticated instruments/equipment used for proteomics, genomics, and metabolomics analysis. The current advancement in microfluidic systems' development is achieving momentum and opening new avenues in developing innovative and hybrid methodologies/technologies. This chapter attempts to expound the micro/nanofluidic systems/devices for their wide-ranging application to detect and separate protein. It covers microfluidic chip electrophoresis, microchip gel electrophoresis, and nanofluidic systems as protein separation systems, while methods such as spectrophotometric, mass spectrometry, electrochemical detection, magneto-resistive sensors and dynamic light scattering (DLS) are discussed as proteins' detection system.

Optimisation of an Electrical Impedance Sensor for Use in Microfluidic Chip Electrophoresis

Label-free measurements using impedance sensing could enable microfluidic chip electrophoresis (ME) to be used in point-of-care (POC) diagnostics. However, impedance sensing methods reported in this field need considerable optimisation. GOAL: Develop a novel design process for optimising tetrapolar electrical impedance measurement (TEIM) sensor performance in ME applications through a systematic investigation a) of the impact of a TEIM sensor’s design parameters on its performance in ME and b) of the relationship between the above parameters with those of the microfluidic channel and the sample to be sensed. METHODS: 3D FEM sensitivity simulations, verified experimentally, were carried out to study the impact of sensor and channel parameters on the measured impedance and their interrelationship. Subsequently, the impact of sensor parameters on sensing a sample band’s conductivity and size was investigated. RESULTS: The impact of channel dimensions on transfer impedance measurements is significant. The non-linearity reported for transfer impedance measurement of volume conductors can be manipulated by appropriate sensor parameter design. The sensor performance can be optimised by designing electrode length and measurement electrode distance in relation to the channel height and sample band length, respectively. The sensor performance is not affected by the injection electrode distance. CONCLUSION: There is a relationship between sensor, channel and band parameters and this warrants establishing a systematic design process of TEIM sensors in ME. SIGNIFICANCE: This paper presents a novel approach to optimising the design of TEIM sensors in ME potentially providing significant performance improvements and thus allowing for label-free POC electrophoresis diagnostics.

Gel Electrophoresis Chip Using Joule Heat Self-Dissipation, Short Run Time, and Online Dynamic Imaging.

Gel electrophoresis (GE) is one of the most general tools in biomedicine. However, it suffers from low resolution, and its mechanism has not been fully revealed yet. Herein, we presented the dispersion model of w2 (t) ∝ Tt, showing the band dispersion (w) via temperature (T) and running time (t) control. Second, we designed an efficient GE chip via the time control and rapid Joule heat self-dissipation by thermal conductive plastic (TCP) and electrode buffer. Third, we conducted the simulations on TCP and polymethylmethacrylate (PMMA) chips, unveiling that (i) the temperature of TCP was lower than the PMMA one, (ii) the temperature uniformity of TCP was better than the PMMA one, and (iii) the resolution of TCP was superior to the PMMA one. Fourth, we designed both TCP and PMMA chips for experimentally validating the dispersion model, TCP chip, and simulations. Finally, we applied the TCP chip to thalassemia and model urine protein assays. The TCP chip has merits of high resolution, rapid run of 6-10 min, and low cost. This work paves the way for greatly improving electrophoretic techniques in gel, chip, and capillary via temperature and time control for biologic study, biopharma quality control, clinical diagnosis, and so on.

An electrophoresis approach with online thermal lens detection to monitoring DNA surface coatings on gold nanoparticles

The coverage density of oligonucleotides on the surface of gold nanoparticles (AuNPs) is crucial for optimizing the sensitivity of AuNPs-based biosensors and evaluating the interactions between thiol-functionalized oligonucleotides and AuNPs. In this study, we report a novel approach based on a miniaturized gel electrophoresis chip (MGEC) integrated with online thermal lens detection for monitoring the amount of DNA on the surface of AuNPs. The microcontroller-based digitization board platform enables simultaneous measurement and recording of data. AuNPs were functionalized with a mixed thiol-terminated monolayer containing single stranded DNA at variable density, which is able to load binders for high sensitivity biorecognition. Due to high spatial and temporal resolution of the thermal lens detection system, our approach enables extremely small differences in the electrophoretic mobility of the particles to be resolved. Hence, small differences in the DNA surface density (55–275 nM) on the particles can be easily distinguished in short time (<6 min), not otherwise detectable using conventional UV–Vis spectrophotometers. In addition, the analytical capability of the proposed MGEC was validated measuring the low detection limit for standard AuNPs solutions using a 80 µL buffer, 100 µL gel, and a 37.5 V/cm electrical field. The result showed that the thermal lens signal linearly increased with the concentration of AuNPs over the range of 0.1–10 nM. The detection limit and relative standard deviation were 23 pM and 4%, respectively. We envisage that the system has potential as an advanced instrumental platform for designing biosensors in nanotechnology.

Development of Glucose Meter Using Boric Acid-Modified Carbon Dots as Fluorescent Probe

A glucose meter has been developed utilizing boric acid-modified carbon dots as a fluorescence probe. Boric acid-modified carbon dots produces varying fluorescence emission with varying glucose concentration in water. Boric acid-modified carbon dots mixed with glucose addition was excited by a violet laser (405 nm), then the emission intensity was detected by a photodetector to be converted to an electrical signal that as an input signal for a microcontroller for glucose concentration measurement. The output voltage of the glucose meter is corresponding to the fluorescence emission measured by using a spectrofluorometer with glucose concentration in the boric acid-modified carbon dots. Full Text: PDF ReferencesH. Teymourian, A. Barfidokht, J. Wang, "Electrochemical glucose sensors in diabetes management: an updated review (2010–2020)", Chem. Soc. Rev. 49, 7671 (2020). CrossRef D.C. Klonoff, "Overview of Fluorescence Glucose Sensing: A Technology with a Bright Future", J Diabetes Sci. Technol. 6(6), 1242 (2012). CrossRef J.C. Pickup, F. Hussain, N.D. Evans, O.J. Rolinski, David J.S. Birch, "Fluorescence-based glucose sensors", Biosens. Bioelectron. 20, 2555 (2005). CrossRef H. Fang, G. Kaur, B. Wang, "Progress in Boronic Acid-Based Fluorescent Glucose Sensors", J. Fluoresc. 14(5), 481 (2004). CrossRef T. Kawanishi, M.A. Romey, P.C. Zhu, M.Z. Holody, S. Shinkai, "A Study of Boronic Acid Based Fluorescent Glucose Sensors", J. Fluoresc. 14(5), 499 (2004). CrossRef A.S. Krishna, P.A. Nair, C. Radhakumary, K. Sreenivasan, "Carbon dot based non enzymatic approach for the detection and estimation of glucose in blood serum", Mater. Res. Express 3(1), 055001 (2016). CrossRef G.P.C. Mello, E.F.C. Simões, D.M.A. Crista, J.M.M. Leitão, L. Pinto da Silva, J.C.G. Esteves da Silva, "Glucose Sensing by Fluorescent Nanomaterials", Crit. Rev. Anal. Chem. 49(6), 542 (2019). CrossRef X. Shan, L. Chai, J. Ma, Z. Qian, J. Chen, H. Feng, "B-doped carbon quantum dots as a sensitive fluorescence probe for hydrogen peroxide and glucose detection", Analyst 139, 2322 (2014). CrossRef J. Dong, S. Li, H. Wang, Q. Meng, L. Fan, H. Xie, C. Cao, W. Zhang, "Simple Boric Acid-Based Fluorescent Focusing for Sensing of Glucose and Glycoprotein via Multipath Moving Supramolecular Boundary Electrophoresis Chip", Anal. Chem. 85(12), 5884 (2013). CrossRef Y. Cui, F. Chen, X-B. Yin, "A ratiometric fluorescence platform based on boric-acid-functional Eu-MOF for sensitive detection of H2O2 and glucose", Biosens. Bioelectron. 135, 208 (2019). CrossRef

On-chip Paper Electrophoresis for Ultrafast Screening of Infectious Diseases

The outbreak of new viral strains promotes advances in universal diagnostic techniques for detecting infectious diseases with unknown viral sequence. Long double-stranded RNA (dsRNA), a hallmark of infections, serves as a virus marker for prompt detection of viruses with unknown genomes. Here, we report on-chip paper electrophoresis for ultrafast screening of infectious diseases. Negatively charged RNAs pass through the micro and nanoscale pores of cellulose in order of size under an external electric field applied to the paper microfluidic channel. Quantitative separation of long dsRNA mimicking poly I:C was analyzed from 1.67 to 33 ng·μL−1, which is close to the viral dsRNA concentration in infected cells. This paper-based capillary electrophoresis chip (paper CE chip) can provide a new diagnostic platform for ultrafast viral disease detection at the point-of-care (POC) level.