We demonstrate an innovative method of PCR product identification that is based on thermal denatu... more We demonstrate an innovative method of PCR product identification that is based on thermal denaturation of PCR product-captured bead using integrated BioFET. Laborious purification and concentration of PCR product were easily carried by capturing the samples on the solid surface like microbeads. When temperature raised upto the denaturation point of PCR product, potential of BioFET is changed by mobile DNA in solution from PCR product-captured beads. By differentiating potential change with respect to temperature change, melting temperature can be determined. In this way, we successfully discriminated three kinds of PCR product using their different melting temperature and improved sensitivity of detection. We expect that proposed method can potentially be used for the identification of multiplex PCR products.
Small (Weinheim an der Bergstrasse, Germany), 2018
Cancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effec... more Cancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effective treatments for each individual patient. Drug combinations have been widely accepted in cancer treatment for better therapeutic efficacy as compared to a single compound. However, experimental complexity and cost grow exponentially with more target compounds under investigation. The primary challenge remains to efficiently perform a large-scale drug combination screening using a small number of patient primary samples for testing. Here, a scalable, easy-to-use, high-throughput drug combination screening scheme is reported, which has the potential of screening all possible pairwise drug combinations for arbitrary number of drugs with multiple logarithmic mixing ratios. A "Christmas tree mixer" structure is introduced to generate a logarithmic concentration mixing ratio between drug pairs, providing a large drug concentration range for screening. A three-layer structure desig...
Cell migratory direction and speed are predicted based on morphological features using computer v... more Cell migratory direction and speed are predicted based on morphological features using computer vision and machine learning algorithms.
Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have ... more Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have lymph node involvement and one-third of patients already have distant metastasis at diagnosis. This propensity for metastasis is a hallmark of IBC distinguishing it from less lethal non-inflammatory breast cancers (nIBC). Genetic profiling studies have been conducted to differentiate IBC from nIBC, but no IBC cancer-cell-specific gene signature has been identified. We hypothesized that a tumor-extrinsic factor, notably tumor-associated macrophages, promotes and contributes to IBC's extreme metastatic phenotype. To this end, we studied the effect of macrophage-conditioned media (MCM) on IBC. We show that two IBC cell lines are hyper-responsive to MCM as compared to normal-like breast and aggressive nIBC cell lines. We further interrogated IBC's hyper-responsiveness to MCM using a microfluidic migration device, which permits individual cell migration path tracing. We found the MCM ...
3D cell culture in the extracellular matrix (ECM), which not only provides structural support to ... more 3D cell culture in the extracellular matrix (ECM), which not only provides structural support to cellular constituents, but also initiates regulatory biochemical cues for a variety of important cell functions in tissue, has become more and more important in understanding cancer pathology and drug testing. Although the ECM-gel has been used in cell culture both in bulk and on-chip, previous studies focused on collective cell behavior rather than single-cell heterogeneity. To track the behavior of each individual cell, we have developed a gel-island chip, which can form thousands of islands containing single cells encapsulated by the desired ECM. Optimized by Poisson's distribution, the device can attain 34% single cell capture efficiency of the exact number of single cells per island. A good culture media exchange rate and high cell viability can be achieved in the gel-islands. The cells in the islands can be automatically counted for high-throughput analysis. As a proof of conce...
Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and rec... more Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10-100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitate...
Photodynamic therapy (PDT), wherein light sensitive non-toxic agents are locally and selectively ... more Photodynamic therapy (PDT), wherein light sensitive non-toxic agents are locally and selectively activated using light, has emerged as an appealing alternative to traditional cancer chemotherapy. Yet to date, PDT efficacy has been mostly characterized using 2D cultures. Compared to 2D cultures, 3D sphere culture generates unique spatial distributions of nutrients and oxygen for the cells that better mimics the in-vivo conditions. Using a novel polyHEMA (non-adherent polymer) fabrication process, we developed a microfluidic sphere formation platform that can (1) generate 1,024 uniform (size variation <10%) cancer spheres within a 2 cm by 2 cm core area, (2) culture spheres for more than 2 weeks, and (3) allow the retrieval of spheres. Using the presented platform, we have successfully characterized the different responses in 2D and 3D cell culture to PDT. Furthermore, we investigated the treatment resistance effect in cancer cells induced by tumor associated fibroblasts (CAF). Alt...
We present a new way of multi-spectral fluorescence microscopy using the embedded liquid filters ... more We present a new way of multi-spectral fluorescence microscopy using the embedded liquid filters in a microfluidic chip, providing flexibility of filter changes for target fluorescence wavelengths and low-cost assays for point-of-care (POC) appli-cations. Widely available food color solutions are adopted for emission filter to absorb residual excitation light. Absorbance of the microfluidic liquid filter was measured for various dye concentrations and filter layer thicknesses. Also, absorbance spectrum of two different color mixtures was investigated for tuning the filter wavelength. Both results match with theoretical Beer-Lambert Law. On-chip liquid-filter fluorescence imaging was demonstrated with multiple LED light sources and fluoro-phores. Live (green)/dead (red) fluorescence images of C6 cells viability assays were successfully demonstrated using the fa-bricated microchip with the embedded liquid filters. The images taken with the liquid filter were comparable to those from t...
Tumor cell migration toward and intravasation into capillaries is an early and key event in cance... more Tumor cell migration toward and intravasation into capillaries is an early and key event in cancer metastasis, yet not all cancer cells are imbued with the same capability to do so. This heterogeneity within a tumor is a fundamental property of cancer. Tools to help us understand what molecular characteristics allow a certain subpopulation of cells to spread from the primary tumor are thus critical for overcoming metastasis. Conventional in vitro migration platforms treat populations in aggregate, which leads to a masking of intrinsic differences among cells. Some migration assays reported recently have single-cell resolution, but these platforms do not provide for selective retrieval of the distinct migrating and non-migrating cell populations for further analysis. Thus, to study the intrinsic differences in cells responsible for chemotactic heterogeneity, we developed a single-cell migration platform so that individual cells' migration behavior can be studied and the heterogen...
Cancer heterogeneity has received considerable attention for its role in tumor initiation and pro... more Cancer heterogeneity has received considerable attention for its role in tumor initiation and progression, and its implication for diagnostics and therapeutics in the clinic. To facilitate a cellular heterogeneity study in a low cost and highly efficient manner, we present a microfluidic platform that allows traceable clonal culture and characterization. The platform captures single cells into a microwell array and cultures them for clonal expansion, subsequently allowing on-chip characterization of clonal phenotype and response against drug treatments. Using a heterogeneous prostate cancer model, the PC3 cell line, we verified our prototype, identifying three different sub-phenotypes and correlating their clonal drug responsiveness to cell phenotype.
We demonstrate an innovative method of PCR product identification that is based on thermal denatu... more We demonstrate an innovative method of PCR product identification that is based on thermal denaturation of PCR product-captured bead using integrated BioFET. Laborious purification and concentration of PCR product were easily carried by capturing the samples on the solid surface like microbeads. When temperature raised upto the denaturation point of PCR product, potential of BioFET is changed by mobile DNA in solution from PCR product-captured beads. By differentiating potential change with respect to temperature change, melting temperature can be determined. In this way, we successfully discriminated three kinds of PCR product using their different melting temperature and improved sensitivity of detection. We expect that proposed method can potentially be used for the identification of multiplex PCR products.
Small (Weinheim an der Bergstrasse, Germany), 2018
Cancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effec... more Cancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effective treatments for each individual patient. Drug combinations have been widely accepted in cancer treatment for better therapeutic efficacy as compared to a single compound. However, experimental complexity and cost grow exponentially with more target compounds under investigation. The primary challenge remains to efficiently perform a large-scale drug combination screening using a small number of patient primary samples for testing. Here, a scalable, easy-to-use, high-throughput drug combination screening scheme is reported, which has the potential of screening all possible pairwise drug combinations for arbitrary number of drugs with multiple logarithmic mixing ratios. A "Christmas tree mixer" structure is introduced to generate a logarithmic concentration mixing ratio between drug pairs, providing a large drug concentration range for screening. A three-layer structure desig...
Cell migratory direction and speed are predicted based on morphological features using computer v... more Cell migratory direction and speed are predicted based on morphological features using computer vision and machine learning algorithms.
Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have ... more Inflammatory breast cancer (IBC) is the most lethal form of breast cancer. All IBC patients have lymph node involvement and one-third of patients already have distant metastasis at diagnosis. This propensity for metastasis is a hallmark of IBC distinguishing it from less lethal non-inflammatory breast cancers (nIBC). Genetic profiling studies have been conducted to differentiate IBC from nIBC, but no IBC cancer-cell-specific gene signature has been identified. We hypothesized that a tumor-extrinsic factor, notably tumor-associated macrophages, promotes and contributes to IBC's extreme metastatic phenotype. To this end, we studied the effect of macrophage-conditioned media (MCM) on IBC. We show that two IBC cell lines are hyper-responsive to MCM as compared to normal-like breast and aggressive nIBC cell lines. We further interrogated IBC's hyper-responsiveness to MCM using a microfluidic migration device, which permits individual cell migration path tracing. We found the MCM ...
3D cell culture in the extracellular matrix (ECM), which not only provides structural support to ... more 3D cell culture in the extracellular matrix (ECM), which not only provides structural support to cellular constituents, but also initiates regulatory biochemical cues for a variety of important cell functions in tissue, has become more and more important in understanding cancer pathology and drug testing. Although the ECM-gel has been used in cell culture both in bulk and on-chip, previous studies focused on collective cell behavior rather than single-cell heterogeneity. To track the behavior of each individual cell, we have developed a gel-island chip, which can form thousands of islands containing single cells encapsulated by the desired ECM. Optimized by Poisson's distribution, the device can attain 34% single cell capture efficiency of the exact number of single cells per island. A good culture media exchange rate and high cell viability can be achieved in the gel-islands. The cells in the islands can be automatically counted for high-throughput analysis. As a proof of conce...
Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and rec... more Proteolytic degradation of the extracellular matrix (ECM) is critical in cancer invasion, and recent work suggests that heterogeneous cancer populations cooperate in this process. Despite the importance of cell heterogeneity, conventional proteolytic assays measure average activity, requiring thousands of cells and providing limited information about heterogeneity and dynamics. Here, we developed a microfluidic platform that provides high-efficiency cell loading and simple valveless isolation, so the proteolytic activity of a small sample (10-100 cells) can be easily characterized. Combined with a single cell derived (clonal) sphere formation platform, we have successfully demonstrated the importance of microenvironmental cues for proteolytic activity and also investigated the difference between clones. Furthermore, the platform allows monitoring single cells at multiple time points, unveiling different cancer cell line dynamics in proteolytic activity. The presented tool facilitate...
Photodynamic therapy (PDT), wherein light sensitive non-toxic agents are locally and selectively ... more Photodynamic therapy (PDT), wherein light sensitive non-toxic agents are locally and selectively activated using light, has emerged as an appealing alternative to traditional cancer chemotherapy. Yet to date, PDT efficacy has been mostly characterized using 2D cultures. Compared to 2D cultures, 3D sphere culture generates unique spatial distributions of nutrients and oxygen for the cells that better mimics the in-vivo conditions. Using a novel polyHEMA (non-adherent polymer) fabrication process, we developed a microfluidic sphere formation platform that can (1) generate 1,024 uniform (size variation <10%) cancer spheres within a 2 cm by 2 cm core area, (2) culture spheres for more than 2 weeks, and (3) allow the retrieval of spheres. Using the presented platform, we have successfully characterized the different responses in 2D and 3D cell culture to PDT. Furthermore, we investigated the treatment resistance effect in cancer cells induced by tumor associated fibroblasts (CAF). Alt...
We present a new way of multi-spectral fluorescence microscopy using the embedded liquid filters ... more We present a new way of multi-spectral fluorescence microscopy using the embedded liquid filters in a microfluidic chip, providing flexibility of filter changes for target fluorescence wavelengths and low-cost assays for point-of-care (POC) appli-cations. Widely available food color solutions are adopted for emission filter to absorb residual excitation light. Absorbance of the microfluidic liquid filter was measured for various dye concentrations and filter layer thicknesses. Also, absorbance spectrum of two different color mixtures was investigated for tuning the filter wavelength. Both results match with theoretical Beer-Lambert Law. On-chip liquid-filter fluorescence imaging was demonstrated with multiple LED light sources and fluoro-phores. Live (green)/dead (red) fluorescence images of C6 cells viability assays were successfully demonstrated using the fa-bricated microchip with the embedded liquid filters. The images taken with the liquid filter were comparable to those from t...
Tumor cell migration toward and intravasation into capillaries is an early and key event in cance... more Tumor cell migration toward and intravasation into capillaries is an early and key event in cancer metastasis, yet not all cancer cells are imbued with the same capability to do so. This heterogeneity within a tumor is a fundamental property of cancer. Tools to help us understand what molecular characteristics allow a certain subpopulation of cells to spread from the primary tumor are thus critical for overcoming metastasis. Conventional in vitro migration platforms treat populations in aggregate, which leads to a masking of intrinsic differences among cells. Some migration assays reported recently have single-cell resolution, but these platforms do not provide for selective retrieval of the distinct migrating and non-migrating cell populations for further analysis. Thus, to study the intrinsic differences in cells responsible for chemotactic heterogeneity, we developed a single-cell migration platform so that individual cells' migration behavior can be studied and the heterogen...
Cancer heterogeneity has received considerable attention for its role in tumor initiation and pro... more Cancer heterogeneity has received considerable attention for its role in tumor initiation and progression, and its implication for diagnostics and therapeutics in the clinic. To facilitate a cellular heterogeneity study in a low cost and highly efficient manner, we present a microfluidic platform that allows traceable clonal culture and characterization. The platform captures single cells into a microwell array and cultures them for clonal expansion, subsequently allowing on-chip characterization of clonal phenotype and response against drug treatments. Using a heterogeneous prostate cancer model, the PC3 cell line, we verified our prototype, identifying three different sub-phenotypes and correlating their clonal drug responsiveness to cell phenotype.
Uploads
Papers by Euisik Yoon