The Experts below are selected from a list of 178533 Experts worldwide ranked by ideXlab platform
Nancy L Allbritton - One of the best experts on this subject based on the ideXlab platform.
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micro Total Analysis Systems fundamental advances and applications in the laboratory clinic and field
Analytical Chemistry, 2013Co-Authors: Michelle L Kovarik, Philip C Gach, Douglas M Ornoff, Yuli Wang, Adam T Melvin, Nicholas C Dobes, Alexandra J Dickinson, Pavak K Shah, Nancy L AllbrittonAbstract:Applications of micro Total Analysis Systems (μTAS) span basic-science research, clinical medicine, and field work. Assay devices designed for these applications offer improvements to existing methods or provide fundamentally new strategies. Both mature methods and novel techniques have benefited from the increased throughput, integration and miniaturization afforded by μTAS. Traditional assays such Western blots and binding assays are recapitulated in a μTAS format but with reduced reagent usage, decreased performance times and added capabilities. An increasingly vibrant area is the performance of drug screening and toxicology assays on-chip, enabling the efficient screening of very large numbers of molecules. Similarly, recent μTAS reactors demonstrate greater chemical synthetic yields and novel product synthesis compared to macro-Systems, often as a result of accurate control over reaction conditions including precision reagent dispensing. These exciting Systems are now enabling on-site production of short-lived radioactive compounds for medical applications. The greatest impact of μTAS may very well be the ability to perform massively parallel laboratory experiments, for example, the use millions of reaction vessels or the Analysis of hundreds of thousands of single cells. Another strength of μTAS lies in the creation of multicellular communities, for example, the combination of many cell types into an interacting system to explore intercellular communication. Devices with multiple layers of co-cultured tissues benefit from precise placement of molecules, such as extracellular matrices or growth factors, in both space and time. Similarly, the complexity and variety of organ-on-chip and organism-on-chip technologies continues to escalate rapidly. Impressively, the types of organisms cultured on-chip now range from the simplest bacteria to complex animals such as fish. Automation, reliability, and integration must all increase as a device moves from the specialist environment of a lab to usage by non-expert personnel in the outside world, for example, at a clinical point-of-care or in environmental monitoring. Key innovations in recent months result in devices that operate with minimal external equipment, error-free operation, and unambiguous readouts, all critical for operation by untrained personnel. Lightweight, portable devices are increasingly used to identify chemical and biological toxins in water, air and soil with applications in public health, defense, and homeland security. Perhaps most exciting is the development of μTAS with sufficient robustness for operation in challenging environments, such as the ocean and outer space. A central component of these Systems is the ability to withstand the unexpected. These Systems push the boundaries of current integration principles and spur rapid growth of new design philosophies. This review focuses on advances in the area of μTAS or “lab-on-a-chip” Systems over the time span of May 2011 through September 2012 with a focus on applications in basic research, clinical medicine and field usage. A range of journals with 2011 impact factors from 2.0 to 36.3 were screened to cover publications with highly specialized content as well as those directed at multidisciplinary audiences. These publications included discipline-specific journals such as Analytical Chemistry and Lab on a Chip as well as general scientific publications, e.g. Science and Nature. To identify material beyond the individually examined journals, extensive key word searches in databases such as PubMed, SciFinder, and Web of Science were performed. Recent reviews in the area of μTAS were also examined for appropriate references. Care was taken to identify impactful and exciting work from across the globe. Well over a thousand papers in the three target areas were identified and discussed. Due to space limitations, we were unable to include all papers but instead incorporated those most fitting into the review scheme and those reporting innovations in basic microdevice technology as well as in applications to biological, physical and engineering sciences. We apologize in advance for omitted papers and welcome feedback regarding any oversights on our part.
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micro Total Analysis Systems for cell biology and biochemical assays
Analytical Chemistry, 2012Co-Authors: Michelle L Kovarik, Philip C Gach, Douglas M Ornoff, Yuli Wang, Joseph Balowski, Lila Farrag, Nancy L AllbrittonAbstract:Novel applications of micro Total Analysis Systems (µTAS) are addressing fundamental biological questions, creating new biomedical reagents, and developing innovative cell and biochemical assays. These efforts impact progress in all areas of µTAS from materials to fluidic handling as well as detection and external control Systems. Three areas show the greatest current and potential impact on the biomedical sciences: improvements in device fabrication and operation, development of enabling technologies, and advancements at the interface with biology (Figure 1). The range of materials from which devices can be fabricated has expanded considerably and now includes paper, fabric and thread, and a multitude of polymers as well as more conventional materials. Thus device substrates and component materials suitable for nearly all biological applications are readily available. Devices are also becoming increasingly integrated with advancements in sample handling and preparation, key first steps in any biological Analysis. Another growing area focuses on modular components that can be mixed and matched on-demand and applied to many different assays, so-called programmable microfluidics. This development should enhance the rate at which new bioassays are generated as well as customize existing experimental protocols. A second area of rapid advancement has been the development new technologies that enable assays that cannot be efficiently performed by any method except µTAS. Novel analyses of single cells are enabled due to effective manipulation of picoliter-scale volumes. Synthesis and screening of large-scale libraries has become increasingly feasible due to the fast processing speeds and combinatorial mixing of reagents provided by lab-on-chip Systems. Increased automation within a completely contained system has now begun to provide some of the first true µTAS diagnostic devices for clinical medicine. The third area in which µTAS has begun to yield high dividends is the interfacing of living entities with microdevices to create biological communities, including tissues and organs on-chip. Control of cell placement in multiple dimensions has produced biological Systems midway between the conventional tissue-culture dish and an intact animal. Thus the complexities of living constructs can be recreated in a controlled experimental environment permitting groundbreaking biological questions to be addressed. Application of µTAS in all of these areas continues to be highly interdisciplinary, utilizing techniques and strategies from almost every scientific field. This multidisciplinary focus insures continued relevance to the biological community as well as a bright future. Figure 1 We highlight recent contributions to µTAS in three interlocking areas: fabrication & operation, enabling technologies, and interfacing with biology. Due to the rapid progress of µTAS or “lab-on-a-chip” Systems, this review focuses on advances impacting cell biology and biochemistry and covers the time span from March 2010 through August 2011. The material for the review was compiled using several strategies: reviews of high impact journals such as Analytical Chemistry, Lab on a Chip, Science, Nature, and PNAS; extensive key word searches in databases such as PubMed, SciFinder, Web of Science, and Google Scholar; and screens of other recent topical reviews. Although several thousand papers were identified and over a thousand papers received a detailed examination, we focused on the most novel and exciting methods, devices, and applications in the areas of cell biology and biochemistry. We also endeavored to cover the most prominent work from a range of labs and countries. Ultimately we were limited by space constraints and our desire to craft a readable commentary on the state of the field. We apologize in advance for omitted papers and welcome feedback regarding any oversights on our part.
Zhongqun Tian - One of the best experts on this subject based on the ideXlab platform.
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confined chemical etching for electrochemical machining with nanoscale accuracy
Accounts of Chemical Research, 2016Co-Authors: Dongping Zhan, Lianhuan Han, Jie Zhang, Kang Shi, Jianzhang Zhou, Zhaowu Tian, Zhongqun TianAbstract:ConspectusIn the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly, ECM possesses several advantages over mechanical machining, such as high removal rate, the capability of making complex three-dimensional structures, and the practicability for difficult-to-cut materials. Additionally, ECM avoids tool wear and thermal or mechanical stress on machining surfaces. Thus, ECM is widely used for various industrial applications in the fields of aerospace, automobiles, electronics, etc.Nowadays, miniaturization and integration of functional components are becoming significant in ultralarge scale integration (ULSI) circuits, microelectromechanical Systems (MEMS), and miniaturized Total Analysis Systems (μ-TAS). As predict...
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confined chemical etching for electrochemical machining with nanoscale accuracy
Accounts of Chemical Research, 2016Co-Authors: Dongping Zhan, Jie Zhang, Jianzhang Zhou, Zhaowu Tian, Zhongqun TianAbstract:ConspectusIn the past several decades, electrochemical machining (ECM) has enjoyed the reputation of a powerful technique in the manufacturing industry. Conventional ECM methods can be classified as electrolytic machining and electroforming: the former is based on anodic dissolution and the latter is based on cathodic deposition of metallic materials. Strikingly, ECM possesses several advantages over mechanical machining, such as high removal rate, the capability of making complex three-dimensional structures, and the practicability for difficult-to-cut materials. Additionally, ECM avoids tool wear and thermal or mechanical stress on machining surfaces. Thus, ECM is widely used for various industrial applications in the fields of aerospace, automobiles, electronics, etc.Nowadays, miniaturization and integration of functional components are becoming significant in ultralarge scale integration (ULSI) circuits, microelectromechanical Systems (MEMS), and miniaturized Total Analysis Systems (μ-TAS). As predict...
Peter C Innis - One of the best experts on this subject based on the ideXlab platform.
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wireless bipolar electrode based textile electrofluidics towards novel micro Total Analysis Systems
Lab on a Chip, 2021Co-Authors: Jawairia Umar Khan, Andres Ruland, Sepidar Sayyar, Brett Paull, Jun Chen, Peter C InnisAbstract:Point of care testing using micro-Total-Analysis Systems (μTAS) is critical to emergent healthcare devices with rapid and robust responses. However, two major barriers to the success of this approach are the prohibitive cost of microchip fabrication and poor sensitivity due to small sample volumes in a microfluidic format. Here, we aimed to replace the complex microchip format with a low-cost textile substrate with inherently built microchannels using the fibers' spaces. Secondly, by integrating this textile-based microfluidics with electrophoresis and wireless bipolar electrochemistry, we can significantly improve solute detection by focusing and concentrating the analytes of interest. Herein, we demonstrated that an in situ metal electrode simply inserted inside the textile-based electrophoretic system can act as a wireless bipolar electrode (BPE) that generates localized electric field and pH gradients adjacent to the BPE and extended along the length of the textile construct. As a result, charged analytes were not only separated electrophoretically but also focused where their electrophoretic migration and counter flow (EOF) balances due to redox reactions proceeding at the BPE edges. The developed wireless redox focusing technique on textile constructs was shown to achieve a 242-fold enrichment of anionically charged solute over an extended time of 3000 s. These findings suggest a simple route that achieves separation and analyte focusing on low-cost surface-accessible inverted substrates, which is far simpler than the more complex ITP on conventional closed and inaccessible capillary channels.
Jongyoon Han - One of the best experts on this subject based on the ideXlab platform.
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pressure modulated selective electrokinetic trapping for direct enrichment purification and detection of nucleic acids in human serum
Analytical Chemistry, 2018Co-Authors: Wei Ouyang, Jongyoon HanAbstract:Micro Total-Analysis Systems (μTAS) have been extensively developed for the detection of nucleic acids (NAs) in resource-limited settings in recent years, yet the sample-preparation steps that interface real-world samples with on-chip analytics remain as the technical bottleneck. We report pressure-modulated selective electrokinetic trapping (PM-SET) for the direct enrichment, purification, and detection of NAs in human serum in one step without involving tedious solid-phase extraction, chemical amplification, and surface-hybridization-based assays. Under appropriately modulated hydrostatic pressures, NAs in human serum were selectively enriched in an electrokinetic concentrator with the majority of background proteins removed, achieving an enrichment factor of >4800 in 15 min. A sequence-specific NA was detected simultaneously during the enrichment process using a complementary morpholino (MO) probe, realizing a limit of detection of 3 pM in 15 min. PM-SET greatly reduces the cost, time, and complexity o...
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Pressure-Modulated Selective Electrokinetic Trapping for Direct Enrichment, Purification, and Detection of Nucleic Acids in Human Serum
2018Co-Authors: Wei Ouyang, Jongyoon HanAbstract:Micro Total-Analysis Systems (μTAS) have been extensively developed for the detection of nucleic acids (NAs) in resource-limited settings in recent years, yet the sample-preparation steps that interface real-world samples with on-chip analytics remain as the technical bottleneck. We report pressure-modulated selective electrokinetic trapping (PM-SET) for the direct enrichment, purification, and detection of NAs in human serum in one step without involving tedious solid-phase extraction, chemical amplification, and surface-hybridization-based assays. Under appropriately modulated hydrostatic pressures, NAs in human serum were selectively enriched in an electrokinetic concentrator with the majority of background proteins removed, achieving an enrichment factor of >4800 in 15 min. A sequence-specific NA was detected simultaneously during the enrichment process using a complementary morpholino (MO) probe, realizing a limit of detection of 3 pM in 15 min. PM-SET greatly reduces the cost, time, and complexity of sample preparation for NA detection and could be easily interfaced with existing NA-detection devices to achieve true sample-to-answer biomolecular analytics
Michelle L Kovarik - One of the best experts on this subject based on the ideXlab platform.
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micro Total Analysis Systems fundamental advances and applications in the laboratory clinic and field
Analytical Chemistry, 2013Co-Authors: Michelle L Kovarik, Philip C Gach, Douglas M Ornoff, Yuli Wang, Adam T Melvin, Nicholas C Dobes, Alexandra J Dickinson, Pavak K Shah, Nancy L AllbrittonAbstract:Applications of micro Total Analysis Systems (μTAS) span basic-science research, clinical medicine, and field work. Assay devices designed for these applications offer improvements to existing methods or provide fundamentally new strategies. Both mature methods and novel techniques have benefited from the increased throughput, integration and miniaturization afforded by μTAS. Traditional assays such Western blots and binding assays are recapitulated in a μTAS format but with reduced reagent usage, decreased performance times and added capabilities. An increasingly vibrant area is the performance of drug screening and toxicology assays on-chip, enabling the efficient screening of very large numbers of molecules. Similarly, recent μTAS reactors demonstrate greater chemical synthetic yields and novel product synthesis compared to macro-Systems, often as a result of accurate control over reaction conditions including precision reagent dispensing. These exciting Systems are now enabling on-site production of short-lived radioactive compounds for medical applications. The greatest impact of μTAS may very well be the ability to perform massively parallel laboratory experiments, for example, the use millions of reaction vessels or the Analysis of hundreds of thousands of single cells. Another strength of μTAS lies in the creation of multicellular communities, for example, the combination of many cell types into an interacting system to explore intercellular communication. Devices with multiple layers of co-cultured tissues benefit from precise placement of molecules, such as extracellular matrices or growth factors, in both space and time. Similarly, the complexity and variety of organ-on-chip and organism-on-chip technologies continues to escalate rapidly. Impressively, the types of organisms cultured on-chip now range from the simplest bacteria to complex animals such as fish. Automation, reliability, and integration must all increase as a device moves from the specialist environment of a lab to usage by non-expert personnel in the outside world, for example, at a clinical point-of-care or in environmental monitoring. Key innovations in recent months result in devices that operate with minimal external equipment, error-free operation, and unambiguous readouts, all critical for operation by untrained personnel. Lightweight, portable devices are increasingly used to identify chemical and biological toxins in water, air and soil with applications in public health, defense, and homeland security. Perhaps most exciting is the development of μTAS with sufficient robustness for operation in challenging environments, such as the ocean and outer space. A central component of these Systems is the ability to withstand the unexpected. These Systems push the boundaries of current integration principles and spur rapid growth of new design philosophies. This review focuses on advances in the area of μTAS or “lab-on-a-chip” Systems over the time span of May 2011 through September 2012 with a focus on applications in basic research, clinical medicine and field usage. A range of journals with 2011 impact factors from 2.0 to 36.3 were screened to cover publications with highly specialized content as well as those directed at multidisciplinary audiences. These publications included discipline-specific journals such as Analytical Chemistry and Lab on a Chip as well as general scientific publications, e.g. Science and Nature. To identify material beyond the individually examined journals, extensive key word searches in databases such as PubMed, SciFinder, and Web of Science were performed. Recent reviews in the area of μTAS were also examined for appropriate references. Care was taken to identify impactful and exciting work from across the globe. Well over a thousand papers in the three target areas were identified and discussed. Due to space limitations, we were unable to include all papers but instead incorporated those most fitting into the review scheme and those reporting innovations in basic microdevice technology as well as in applications to biological, physical and engineering sciences. We apologize in advance for omitted papers and welcome feedback regarding any oversights on our part.
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micro Total Analysis Systems for cell biology and biochemical assays
Analytical Chemistry, 2012Co-Authors: Michelle L Kovarik, Philip C Gach, Douglas M Ornoff, Yuli Wang, Joseph Balowski, Lila Farrag, Nancy L AllbrittonAbstract:Novel applications of micro Total Analysis Systems (µTAS) are addressing fundamental biological questions, creating new biomedical reagents, and developing innovative cell and biochemical assays. These efforts impact progress in all areas of µTAS from materials to fluidic handling as well as detection and external control Systems. Three areas show the greatest current and potential impact on the biomedical sciences: improvements in device fabrication and operation, development of enabling technologies, and advancements at the interface with biology (Figure 1). The range of materials from which devices can be fabricated has expanded considerably and now includes paper, fabric and thread, and a multitude of polymers as well as more conventional materials. Thus device substrates and component materials suitable for nearly all biological applications are readily available. Devices are also becoming increasingly integrated with advancements in sample handling and preparation, key first steps in any biological Analysis. Another growing area focuses on modular components that can be mixed and matched on-demand and applied to many different assays, so-called programmable microfluidics. This development should enhance the rate at which new bioassays are generated as well as customize existing experimental protocols. A second area of rapid advancement has been the development new technologies that enable assays that cannot be efficiently performed by any method except µTAS. Novel analyses of single cells are enabled due to effective manipulation of picoliter-scale volumes. Synthesis and screening of large-scale libraries has become increasingly feasible due to the fast processing speeds and combinatorial mixing of reagents provided by lab-on-chip Systems. Increased automation within a completely contained system has now begun to provide some of the first true µTAS diagnostic devices for clinical medicine. The third area in which µTAS has begun to yield high dividends is the interfacing of living entities with microdevices to create biological communities, including tissues and organs on-chip. Control of cell placement in multiple dimensions has produced biological Systems midway between the conventional tissue-culture dish and an intact animal. Thus the complexities of living constructs can be recreated in a controlled experimental environment permitting groundbreaking biological questions to be addressed. Application of µTAS in all of these areas continues to be highly interdisciplinary, utilizing techniques and strategies from almost every scientific field. This multidisciplinary focus insures continued relevance to the biological community as well as a bright future. Figure 1 We highlight recent contributions to µTAS in three interlocking areas: fabrication & operation, enabling technologies, and interfacing with biology. Due to the rapid progress of µTAS or “lab-on-a-chip” Systems, this review focuses on advances impacting cell biology and biochemistry and covers the time span from March 2010 through August 2011. The material for the review was compiled using several strategies: reviews of high impact journals such as Analytical Chemistry, Lab on a Chip, Science, Nature, and PNAS; extensive key word searches in databases such as PubMed, SciFinder, Web of Science, and Google Scholar; and screens of other recent topical reviews. Although several thousand papers were identified and over a thousand papers received a detailed examination, we focused on the most novel and exciting methods, devices, and applications in the areas of cell biology and biochemistry. We also endeavored to cover the most prominent work from a range of labs and countries. Ultimately we were limited by space constraints and our desire to craft a readable commentary on the state of the field. We apologize in advance for omitted papers and welcome feedback regarding any oversights on our part.
