Partial discharge (PD) pulses detected on site usually take on various modes, and it is difficult... more Partial discharge (PD) pulses detected on site usually take on various modes, and it is difficult for wavelet to select proper wavelet basis function in denoising. In particular, in the case of PD cluster with multi-mode, conventional wavelet denoising can hardly give satisfied result. Multi-wavelet is the new development of wavelet theory, extending the idea of wavelet by representing a signal with more than one scaling function, and outperforms wavelet in signal processing. In this contribution, we employ multi-wavelet to detect the partial discharge, investigating its denoising performance. For PD pulse of single-mode or PD cluster of multi-mode, we run massive simulations, using both multi-wavelet denoising and wavelet denoising. The results obtained demonstrate that, in comparison with wavelet, multi-wavelet denoising can preserve more signal features while removing noise from the measured data. In addition, multi-wavelet denoising needs no (or less) prior knowledge of partial ...
A sensitive and compact 3D plasmonic nanosensor was developed by deposition of gold nanoparticles... more A sensitive and compact 3D plasmonic nanosensor was developed by deposition of gold nanoparticles (AuNPs) on a silicon micropillar array for label-free biosensing. This silicon micropillar array also worked as an autonomous capillary pump, capable of transporting a specific amount of bio-samples into the sensing area without external pumping requirement. The developed device greatly decreased system complexity and sample consumption. Both the extinction spectra peak position and the maximum extinction exhibited good linear relationships with the surrounding refractive index of the environment.
Plasmonic interferometric imaging has been widely used for fast and label-free detection to nano-... more Plasmonic interferometric imaging has been widely used for fast and label-free detection to nano-objects, which associates the interference between launched and scattered surface plasmon polaritons (SPPs). As scattering of SPPs is affected by the characteristics of nano-objects, particle size, particle index and particle-interface distances have been retrieved from the imaging. Refractive index of dielectric, which tailors the resonant wavelength of launched SPPs, is also a key issue to plasmonic interferometric imaging. Yet, the influence of refractive index to plasmonic interferometric imaging has not been investigated. In this work, we connected the dielectric refractive index to the interferometric image intensity distribution, and found that both fringe periodicities and intensity profiles along SPP wavefronts were tailored by the refractive index, which is illustrated by using glucose solutions with different concentrations. Our research illustrates the pattern change of plasmonic interferometric imaging induced by dielectric refractive index, which not only paves the way for the basic understanding on the plasmonic interferometric imaging, but also provides a new potential visual method for real-time refractive index sensing and monitoring, which will be applied to food safety and environment monitoring.
The electroporation system can serve as a tool for the intracellular delivery of foreign cargos. ... more The electroporation system can serve as a tool for the intracellular delivery of foreign cargos. However, this technique is presently limited by the inaccurate electric field applied to the single cells and lack of a real-time electroporation metrics subsystem. Here, we reported a microfluidic system for precise and rapid single-cell electroporation and simultaneous impedance monitoring in a constriction microchannel. When single cells (A549) were continuously passing through the constriction microchannel, a localized high electric field was applied on the cell membrane, which resulted in highly efficient (up to 96.6%) electroporation. During a single cell entering the constriction channel, an abrupt impedance drop was noticed and demonstrated to be correlated with the occurrence of electroporation. Besides, while the cell was moving in the constriction channel, the stabilized impedance showed the capability to quantify the electroporation extent. The correspondence of the impedance...
A microsphere mediated exosome isolation and ultra-sensitive detection ExoDEP-chip was developed.... more A microsphere mediated exosome isolation and ultra-sensitive detection ExoDEP-chip was developed. A detection limit of 193 exosomes per mL was obtained by dispersing PS microspheres into microwells to reduce the fluorescence interference.
Circulating tumor cells (CTCs), a type of cancer cell that spreads from primary tumors into human... more Circulating tumor cells (CTCs), a type of cancer cell that spreads from primary tumors into human peripheral blood and are considered as a new biomarker of cancer liquid biopsy. It provides the direction for understanding the biology of cancer metastasis and progression. Isolation and analysis of CTCs offer the possibility for early cancer detection and dynamic prognosis monitoring. The extremely low quantity and high heterogeneity of CTCs are the major challenges for the application of CTCs in liquid biopsy. There have been significant research endeavors to develop efficient and reliable approaches to CTC isolation and analysis in the past few decades. With the advancement of microfabrication and nanomaterials, a variety of approaches have now emerged for CTC isolation and analysis on microfluidic platforms combined with nanotechnology. These new approaches show advantages in terms of cell capture efficiency, purity, detection sensitivity and specificity. This review focuses on rec...
Label-free, fast, and single nanoparticle detection is demanded for the in situ monitoring of nan... more Label-free, fast, and single nanoparticle detection is demanded for the in situ monitoring of nano-pollutants in the environment, which have potential toxic effects on human health. We present the label-free imaging of single nanoparticles by using total internal reflection (TIR)-based leakage radiation microscopy. We illustrate the imaging of both single polystyrene (PS) and Au nanospheres with diameters as low as 100 and 30 nm, respectively. As both far-field imaging and simulated near-field electric field intensity distribution at the interface showed the same characteristics, i.e., the localized enhancement and interference of TIR evanescent waves, we confirmed the leakage radiation, transforming the near-field distribution to far-field for fast imaging. The localized enhancement of single PS and Au nanospheres were compared. We also illustrate the TIR-based leakage radiation imaging of single polystyrene nanospheres with different incident polarizations. The TIR-based leakage r...
The quality of edge detection is related to detection angle, scale, and threshold. There have bee... more The quality of edge detection is related to detection angle, scale, and threshold. There have been many algorithms to promote edge detection quality by some rules about detection angles. However these algorithm did not form rules to detect edges at an arbitrary angle, therefore they just used different number of angles and did not indicate optimized number of angles. In this paper, a novel edge detection algorithm is proposed to detect edges at arbitrary angles and optimized number of angles in the algorithm is introduced. The algorithm combines singularity detection with Gaussian wavelet transform and edge detection at arbitrary directions and contain five steps: 1) An image is divided into some pixel lines at certain angle in the range from 45 • to 90 • according to decomposition rules of this paper. 2) Singularities of pixel lines are detected and form an edge image at the certain angle. 3) Many edge images at different angles form a final edge images. 4) Detection angles in the range from 45 • to 90 • are extended to range from 0 • to 360 •. 5) Optimized number of angles for the algorithm is proposed. Then the algorithm with optimized number of angles shows better performances.
Off-resonant gap-enhanced Raman tags (GERTs) show ultrahigh Raman enhancement and photostabilitie... more Off-resonant gap-enhanced Raman tags (GERTs) show ultrahigh Raman enhancement and photostabilities and therefore can be used as ideal highly photostable nanoprobes for high-speed and high-resolution Raman bioimaging.
This paper presents a crossing constriction channel based microfluidic system for high-throughput... more This paper presents a crossing constriction channel based microfluidic system for high-throughput characterization of specific membrane capacitance (Csm) and cytoplasm conductivity (σcy) of single cells. In operations, cells in suspension...
Carbonyl compounds in water sources are typical characteristic pollutants, which are important in... more Carbonyl compounds in water sources are typical characteristic pollutants, which are important indicators in the health risk assessment of water quality. Commonly used analytical chemistry methods face issues such as complex operations, low sensitivity, and long analysis times. Here, we report a silicon microfluidic device based on click chemical surface modification that was engineered to achieve rapid, convenient and efficient capture of trace level carbonyl compounds in liquid solvent. The micro pillar arrays of the chip and microfluidic channels were designed under the basis of finite element (FEM) analysis and fabricated by the microelectromechanical systems (MEMS) technique. The surface of the micropillars was sputtered with precious metal silver and functionalized with the organic substance amino-oxy dodecane thiol (ADT) by self-assembly for capturing trace carbonyl compounds. The detection of ppb level fluorescent carbonyl compounds demonstrates that the strategy proposed in...
This paper presents a new microfluidic impedance cytometry with crossing constriction microchanne... more This paper presents a new microfluidic impedance cytometry with crossing constriction microchannels, enabling the characterization of cellular electrical markers (e.g., specific membrane capacitance (C) and cytoplasm conductivity (σ)) in large cell populations (~ 100,000 cells) at a rate greater than 100 cells/s. Single cells were aspirated continuously through the major constriction channel with a proper sealing of the side constriction channel. An equivalent circuit model was developed and the measured impedance values were translated to C and σ. Neural network was used to classify different cell populations where classification success rates were calculated. To evaluate the developed technique, different tumour cell lines, and the effects of epithelial-mesenchymal transitions on tumour cells were examined. Significant differences in both C and σ were found for H1299 and HeLa cell lines with a classification success rate of 90.9% in combination of the two parameters. Meanwhile, tu...
International journal of molecular sciences, Jan 19, 2017
This paper presents the instrumentation of a microfluidic analyzer enabling the characterization ... more This paper presents the instrumentation of a microfluidic analyzer enabling the characterization of single-cell biophysical properties, which includes seven key components: a microfluidic module, a pressure module, an imaging module, an impedance module, two LabVIEW platforms for instrument operation and raw data processing, respectively, and a Python code for data translation. Under the control of the LabVIEW platform for instrument operation, the pressure module flushes single cells into the microfluidic module with raw biophysical parameters sampled by the imaging and impedance modules and processed by the LabVIEW platform for raw data processing, which were further translated into intrinsic cellular biophysical parameters using the code developed in Python. Based on this system, specific membrane capacitance, cytoplasm conductivity, and instantaneous Young's modulus of three cell types were quantified as 2.76 ± 0.57 μF/cm², 1.00 ± 0.14 S/m, and 3.79 ± 1.11 kPa for A549 cells...
Partial discharge (PD) pulses detected on site usually take on various modes, and it is difficult... more Partial discharge (PD) pulses detected on site usually take on various modes, and it is difficult for wavelet to select proper wavelet basis function in denoising. In particular, in the case of PD cluster with multi-mode, conventional wavelet denoising can hardly give satisfied result. Multi-wavelet is the new development of wavelet theory, extending the idea of wavelet by representing a signal with more than one scaling function, and outperforms wavelet in signal processing. In this contribution, we employ multi-wavelet to detect the partial discharge, investigating its denoising performance. For PD pulse of single-mode or PD cluster of multi-mode, we run massive simulations, using both multi-wavelet denoising and wavelet denoising. The results obtained demonstrate that, in comparison with wavelet, multi-wavelet denoising can preserve more signal features while removing noise from the measured data. In addition, multi-wavelet denoising needs no (or less) prior knowledge of partial ...
A sensitive and compact 3D plasmonic nanosensor was developed by deposition of gold nanoparticles... more A sensitive and compact 3D plasmonic nanosensor was developed by deposition of gold nanoparticles (AuNPs) on a silicon micropillar array for label-free biosensing. This silicon micropillar array also worked as an autonomous capillary pump, capable of transporting a specific amount of bio-samples into the sensing area without external pumping requirement. The developed device greatly decreased system complexity and sample consumption. Both the extinction spectra peak position and the maximum extinction exhibited good linear relationships with the surrounding refractive index of the environment.
Plasmonic interferometric imaging has been widely used for fast and label-free detection to nano-... more Plasmonic interferometric imaging has been widely used for fast and label-free detection to nano-objects, which associates the interference between launched and scattered surface plasmon polaritons (SPPs). As scattering of SPPs is affected by the characteristics of nano-objects, particle size, particle index and particle-interface distances have been retrieved from the imaging. Refractive index of dielectric, which tailors the resonant wavelength of launched SPPs, is also a key issue to plasmonic interferometric imaging. Yet, the influence of refractive index to plasmonic interferometric imaging has not been investigated. In this work, we connected the dielectric refractive index to the interferometric image intensity distribution, and found that both fringe periodicities and intensity profiles along SPP wavefronts were tailored by the refractive index, which is illustrated by using glucose solutions with different concentrations. Our research illustrates the pattern change of plasmonic interferometric imaging induced by dielectric refractive index, which not only paves the way for the basic understanding on the plasmonic interferometric imaging, but also provides a new potential visual method for real-time refractive index sensing and monitoring, which will be applied to food safety and environment monitoring.
The electroporation system can serve as a tool for the intracellular delivery of foreign cargos. ... more The electroporation system can serve as a tool for the intracellular delivery of foreign cargos. However, this technique is presently limited by the inaccurate electric field applied to the single cells and lack of a real-time electroporation metrics subsystem. Here, we reported a microfluidic system for precise and rapid single-cell electroporation and simultaneous impedance monitoring in a constriction microchannel. When single cells (A549) were continuously passing through the constriction microchannel, a localized high electric field was applied on the cell membrane, which resulted in highly efficient (up to 96.6%) electroporation. During a single cell entering the constriction channel, an abrupt impedance drop was noticed and demonstrated to be correlated with the occurrence of electroporation. Besides, while the cell was moving in the constriction channel, the stabilized impedance showed the capability to quantify the electroporation extent. The correspondence of the impedance...
A microsphere mediated exosome isolation and ultra-sensitive detection ExoDEP-chip was developed.... more A microsphere mediated exosome isolation and ultra-sensitive detection ExoDEP-chip was developed. A detection limit of 193 exosomes per mL was obtained by dispersing PS microspheres into microwells to reduce the fluorescence interference.
Circulating tumor cells (CTCs), a type of cancer cell that spreads from primary tumors into human... more Circulating tumor cells (CTCs), a type of cancer cell that spreads from primary tumors into human peripheral blood and are considered as a new biomarker of cancer liquid biopsy. It provides the direction for understanding the biology of cancer metastasis and progression. Isolation and analysis of CTCs offer the possibility for early cancer detection and dynamic prognosis monitoring. The extremely low quantity and high heterogeneity of CTCs are the major challenges for the application of CTCs in liquid biopsy. There have been significant research endeavors to develop efficient and reliable approaches to CTC isolation and analysis in the past few decades. With the advancement of microfabrication and nanomaterials, a variety of approaches have now emerged for CTC isolation and analysis on microfluidic platforms combined with nanotechnology. These new approaches show advantages in terms of cell capture efficiency, purity, detection sensitivity and specificity. This review focuses on rec...
Label-free, fast, and single nanoparticle detection is demanded for the in situ monitoring of nan... more Label-free, fast, and single nanoparticle detection is demanded for the in situ monitoring of nano-pollutants in the environment, which have potential toxic effects on human health. We present the label-free imaging of single nanoparticles by using total internal reflection (TIR)-based leakage radiation microscopy. We illustrate the imaging of both single polystyrene (PS) and Au nanospheres with diameters as low as 100 and 30 nm, respectively. As both far-field imaging and simulated near-field electric field intensity distribution at the interface showed the same characteristics, i.e., the localized enhancement and interference of TIR evanescent waves, we confirmed the leakage radiation, transforming the near-field distribution to far-field for fast imaging. The localized enhancement of single PS and Au nanospheres were compared. We also illustrate the TIR-based leakage radiation imaging of single polystyrene nanospheres with different incident polarizations. The TIR-based leakage r...
The quality of edge detection is related to detection angle, scale, and threshold. There have bee... more The quality of edge detection is related to detection angle, scale, and threshold. There have been many algorithms to promote edge detection quality by some rules about detection angles. However these algorithm did not form rules to detect edges at an arbitrary angle, therefore they just used different number of angles and did not indicate optimized number of angles. In this paper, a novel edge detection algorithm is proposed to detect edges at arbitrary angles and optimized number of angles in the algorithm is introduced. The algorithm combines singularity detection with Gaussian wavelet transform and edge detection at arbitrary directions and contain five steps: 1) An image is divided into some pixel lines at certain angle in the range from 45 • to 90 • according to decomposition rules of this paper. 2) Singularities of pixel lines are detected and form an edge image at the certain angle. 3) Many edge images at different angles form a final edge images. 4) Detection angles in the range from 45 • to 90 • are extended to range from 0 • to 360 •. 5) Optimized number of angles for the algorithm is proposed. Then the algorithm with optimized number of angles shows better performances.
Off-resonant gap-enhanced Raman tags (GERTs) show ultrahigh Raman enhancement and photostabilitie... more Off-resonant gap-enhanced Raman tags (GERTs) show ultrahigh Raman enhancement and photostabilities and therefore can be used as ideal highly photostable nanoprobes for high-speed and high-resolution Raman bioimaging.
This paper presents a crossing constriction channel based microfluidic system for high-throughput... more This paper presents a crossing constriction channel based microfluidic system for high-throughput characterization of specific membrane capacitance (Csm) and cytoplasm conductivity (σcy) of single cells. In operations, cells in suspension...
Carbonyl compounds in water sources are typical characteristic pollutants, which are important in... more Carbonyl compounds in water sources are typical characteristic pollutants, which are important indicators in the health risk assessment of water quality. Commonly used analytical chemistry methods face issues such as complex operations, low sensitivity, and long analysis times. Here, we report a silicon microfluidic device based on click chemical surface modification that was engineered to achieve rapid, convenient and efficient capture of trace level carbonyl compounds in liquid solvent. The micro pillar arrays of the chip and microfluidic channels were designed under the basis of finite element (FEM) analysis and fabricated by the microelectromechanical systems (MEMS) technique. The surface of the micropillars was sputtered with precious metal silver and functionalized with the organic substance amino-oxy dodecane thiol (ADT) by self-assembly for capturing trace carbonyl compounds. The detection of ppb level fluorescent carbonyl compounds demonstrates that the strategy proposed in...
This paper presents a new microfluidic impedance cytometry with crossing constriction microchanne... more This paper presents a new microfluidic impedance cytometry with crossing constriction microchannels, enabling the characterization of cellular electrical markers (e.g., specific membrane capacitance (C) and cytoplasm conductivity (σ)) in large cell populations (~ 100,000 cells) at a rate greater than 100 cells/s. Single cells were aspirated continuously through the major constriction channel with a proper sealing of the side constriction channel. An equivalent circuit model was developed and the measured impedance values were translated to C and σ. Neural network was used to classify different cell populations where classification success rates were calculated. To evaluate the developed technique, different tumour cell lines, and the effects of epithelial-mesenchymal transitions on tumour cells were examined. Significant differences in both C and σ were found for H1299 and HeLa cell lines with a classification success rate of 90.9% in combination of the two parameters. Meanwhile, tu...
International journal of molecular sciences, Jan 19, 2017
This paper presents the instrumentation of a microfluidic analyzer enabling the characterization ... more This paper presents the instrumentation of a microfluidic analyzer enabling the characterization of single-cell biophysical properties, which includes seven key components: a microfluidic module, a pressure module, an imaging module, an impedance module, two LabVIEW platforms for instrument operation and raw data processing, respectively, and a Python code for data translation. Under the control of the LabVIEW platform for instrument operation, the pressure module flushes single cells into the microfluidic module with raw biophysical parameters sampled by the imaging and impedance modules and processed by the LabVIEW platform for raw data processing, which were further translated into intrinsic cellular biophysical parameters using the code developed in Python. Based on this system, specific membrane capacitance, cytoplasm conductivity, and instantaneous Young's modulus of three cell types were quantified as 2.76 ± 0.57 μF/cm², 1.00 ± 0.14 S/m, and 3.79 ± 1.11 kPa for A549 cells...
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Papers by Chengjun Huang