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Cornell University
1.
Reinholt, Sarah.
Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications.
Degree: M.S., Agricultural and Biological Engineering, Agricultural and Biological Engineering, 2014, Cornell University
URL: http://hdl.handle.net/1813/36169 
► Biosensor technology is a rapidly expanding field of study in which tedious culturing techniques are being replaced by assays that use biorecognition elements such as…
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▼ Biosensor technology is a rapidly expanding field of study in which tedious culturing techniques are being replaced by assays that use biorecognition elements such as antibodies and nucleic acids to detect biological entities. Biosensors have useful applications in areas such as food safety, water quality, clinical analysis, and defense again bioterrorism. Bench-top macro scale detection assays have limitations that restrict them to laboratory settings and require them to be performed by highly-trained personnel. Consequently, there has been a strong emphasis on developing technology that is portable and easy-to-use to enable its use in point-of-care and resource-limited settings. Thus, the concept of a micro total analysis system ([MICRO SIGN]TAS) in which all aspects of the biological assay are contained within a single device is very attractive. Benefits of [MICRO SIGN]TASs over their macro scale counterparts, aside from portability and increased ease-of-use, include smaller sample sizes, reduced reagent consumption, decreased assay time, negligible contamination, and potential automation. Nucleic acid detection within [MICRO SIGN]TASs is a commonly used method for the detection of cells and other microorganisms, as well as genomic analyses. A critical step in these assays is nucleic acid isolation within the microfluidic device. Miniaturizing nucleic acid isolation has led to the discovery of novel isolation techniques. Specific application and assay parameters determine desired characteristics of an optimal nucleic acid purification technique. Relevant parameters include sample type and size, device material and fabrication technologies available, as well as the pre- and post-isolation processes. The main nucleic acid isolation processes used within microfluidic devices are silica-based surfaces, functionalized paramagnetic beads, oligonucleotide-modified polymer surfaces, pH-dependent charged surfaces, aluminum oxide membranes, and liquid-phase isolation. A common process that follows isolation is nucleic acid amplification, and integrating both steps within the same device is key to developing a complete [MICRO SIGN]TAS. Nucleic acid sequence-based amplification (NASBA) is an isothermal amplification technique of which the primary advantage over the standard polymerase chain reaction (PCR) is the elimination of necessary thermal cycles. In this research, nucleic acid isolation and NASBA were integrated within the same simple microchannel to realize highly sensitive detection of very low concentrations of messenger RNA (mRNA). The microchannels were fabricated simply and inexpensively from poly(methyl methacrylate) (PMMA) using hot-embossing and UV/ozone-assisted thermal bonding. Unique surface chemistry modifications, involving the immobilization of polyamidoamine (PAMAM) dendrimers and subsequent covalent attachment of thymidine oligonucleotide probes to the dendrimer periphery, were used to develop a surface to facilitate the capture of mRNA from Cryptosporidium parvum (C. parvum) oocyst lysate, while…
Advisors/Committee Members: Baeumner, Antje J (chair), Kirby, Brian (committee member).
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APA (6th Edition):
Reinholt, S. (2014). Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications. (Masters Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/36169
Chicago Manual of Style (16th Edition):
Reinholt, Sarah. “Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications.” 2014. Masters Thesis, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/36169.
MLA Handbook (7th Edition):
Reinholt, Sarah. “Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications.” 2014. Web. 13 Apr 2021.
Vancouver:
Reinholt S. Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications. [Internet] [Masters thesis]. Cornell University; 2014. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/36169.
Council of Science Editors:
Reinholt S. Developing New Techniques And Materials To Use In Biosensors For Point-Of-Care Applications. [Masters Thesis]. Cornell University; 2014. Available from: http://hdl.handle.net/1813/36169
Cornell University
2.
Tang, Yinan.
Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications.
Degree: M.S., Biomedical Engineering, Biomedical Engineering, 2011, Cornell University
URL: http://hdl.handle.net/1813/29527
► A novel miniaturized amperometric analyzer with enhanced performance was developed to meet the need of field-portable, wide adaptable, user friendly, and cost effective electrochemical detection…
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▼ A novel miniaturized amperometric analyzer with enhanced performance was developed to meet the need of field-portable, wide adaptable, user friendly, and cost effective electrochemical detection in various application fields. Based on the new MSP430FG479 microcontroller, the embedded system was designed to either operate as a stand-alone unit with an on-board fool-proof user interface, or run on the user's PC for advanced data analysis. Amperometric detection is a powerful experimental approach for the study of electro-active compounds with clinical, industrial, environmental and agricultural importance. Inside the amperometric analyzer, a mini-potentiostat is designed to interface with a wide spectrum of electrochemical sensors. Implemented with grounded-auxillary electrode configuration, the mini-potentiostat controls oxidationreduction reactions of target analytes at the working electrode surface by accurately maintaining a preset potential between the working (WE) and the reference electrode (RE), while measuring the redox current response at the auxillary electrode (AE) using a low-side resistive sensing mechanism. In an unstirred solution, at steady state, the rate of electron transfer is directly proportional to the concentration of the reactant. Therefore, the steady state current is used as an accurate measure of the analyte concentration in the sample. Constructed using off-the-shelf IC chips and powered by a single 3V lithium coin cell battery, the potentiostat circuitry inside the amperometric analyzer is designed to meet potential control and current detection requirements for most existing electrochemical sensors. Featured with sub-picoampere sensitive, wide span and high accuracy current sensing, the specially designed current sensing block not only covers general application requirements, but it can also serve as a powerful tool in research efforts toward the next generation of ultra-sensitive detection systems in biomolecular sensing. In addition to the superior electrochemical related specifications, various lowpower design techniques have been applied to ensure a prolonged battery life, therefore making the system an ideal platform for amperometric monitoring in field appropriate applications. Confirmed with a systematic evaluation of the device prototype, the system features a 4-month battery life with a single 3V lithium battery (220mAh), accurate bidirectional redox potential control from -1.2V to +1.2V, high resolution current detection from ±5pA to ±1mA covered by 4 software selectable detection levels, improved stability unaffected by electrochemical sensor impedance, and high EMI immunity without external shielding. Finally, electrochemical analyses were also conducted using the device prototype. For a constant potential amperometric experiment, the experimental results of the system were compared with a standard bench top electrochemical workstation (the BAS Epsilon). Excellent agreement was attained over the whole detection range, which demonstrates the excellent potential control and…
Advisors/Committee Members: Baeumner, Antje J (chair), Lal, Amit (committee member).
Subjects/Keywords: embedded system; potentiostat; amperometric detection; field-portable applications
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APA (6th Edition):
Tang, Y. (2011). Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications. (Masters Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/29527
Chicago Manual of Style (16th Edition):
Tang, Yinan. “Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications.” 2011. Masters Thesis, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/29527.
MLA Handbook (7th Edition):
Tang, Yinan. “Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications.” 2011. Web. 13 Apr 2021.
Vancouver:
Tang Y. Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications. [Internet] [Masters thesis]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/29527.
Council of Science Editors:
Tang Y. Design And Characterization Of An Embedded Amperometric Analyzer For Field-Portable Electrochemical Applications. [Masters Thesis]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/29527
Cornell University
3.
Matlock-Colangelo, Lauren.
Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems.
Degree: M.S., Agricultural and Biological Engineering, Agricultural and Biological Engineering, 2012, Cornell University
URL: http://hdl.handle.net/1813/29389
► Biosensors detect target analytes through specific binding with biological recognition elements such as nucleic acids, enzymes, and antibodies. Many labs are working to create inexpensive…
(more)
▼ Biosensors detect target analytes through specific binding with biological recognition elements such as nucleic acids, enzymes, and antibodies. Many labs are working to create inexpensive and portable miniaturized sensors that allow for rapid sample analysis and low reagent consumption in order to increase biosensor accessibility in rural areas and third world countries. Lab-on-a-chip devices aim to incorporate sample preparation and analyte detection into one device in order to create self-contained sensors that can be used in rural areas and third world countries where laboratory equipment may not be available. Often, these devices incorporate microfluidics in order to shorten reaction times, reduce handling of hazardous samples, and take advantage of laminar flow [1]. However, while several successful lab-on-achip devices have been developed, incorporating sample preparation and analyte detection within one device is still a key challenge in the design of many biosensors. Sample preparation is extremely important for miniaturized sensors, which have a low tolerance for sample impurities and particulates [1]. In addition, significant sample concentration is often required to reduce sample volumes to the nL to mL range used in miniaturized sensors. This research aims to address the need for sample preparation within lab-on-a-chip systems through the use of functionalized electrospun nanofibers within polymer microfluidic devices. Electrospinning is a fiber formation process that uses electrical forces to form fibers with diameters on the order of 100 nm from polymer spinning dopes [2, 3]. The non-woven fiber mats formed during electrospinning have extremely high surface area to volume ratios, and can be used to increase the sensitivity and binding capacity of biosensors without increasing their size. Additionally, the fibers can be functionalized through the incorporation of nano and microscale materials within a polymer spinning dope. In this work, positively and negatively charged v nanofibers were created through the incorporation of hexadimethrine bromide (polybrene) and poly(maleic anhydride) (Poly(MA)) within a poly(vinyl alcohol) spinning dope. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the successful incorporation of polybrene and poly(MA) into the nanofibers. Gold microelectrodes were patterned on poly(methyl methacrylate) (PMMA) to facilitate the incorporation of nanofibers within microfluidic devices. The gold microelectrodes served as grounded collector plates during electrospinning and produced well-aligned nanofiber mats. Microchannels 1 mm wide and 52 [MICRO SIGN]m deep were imprinted into PMMA through hot embossing with a copper template. PMMA pieces embossed with microchannels were bonded to PMMA pieces with gold microelectrodes and nanofibers using UV-assisted thermal bonding. Positively charged polybrene-modified nanofibers were shown to successfully filter negatively charged fluorescent liposomes out of a HEPES-sucrose-saline buffer, while…
Advisors/Committee Members: Baeumner, Antje J (chair), Kirby, Brian (committee member), Frey, Margaret W (committee member).
Subjects/Keywords: Biosensors; Nanofibers; Microfluidics
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APA (6th Edition):
Matlock-Colangelo, L. (2012). Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems. (Masters Thesis). Cornell University. Retrieved from http://hdl.handle.net/1813/29389
Chicago Manual of Style (16th Edition):
Matlock-Colangelo, Lauren. “Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems.” 2012. Masters Thesis, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/29389.
MLA Handbook (7th Edition):
Matlock-Colangelo, Lauren. “Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems.” 2012. Web. 13 Apr 2021.
Vancouver:
Matlock-Colangelo L. Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems. [Internet] [Masters thesis]. Cornell University; 2012. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/29389.
Council of Science Editors:
Matlock-Colangelo L. Functionalized Electrospun Nanofibers In Microfluidic Bioanalytical Systems. [Masters Thesis]. Cornell University; 2012. Available from: http://hdl.handle.net/1813/29389
Cornell University
4.
Connelly, John.
Bioanalytical Microsystems For Waterborne Pathogen Detection.
Degree: PhD, Agricultural and Biological Engineering, 2011, Cornell University
URL: http://hdl.handle.net/1813/30675
► Waterborne pathogens are a global health concern, with 1 billion people having no access to uncontaminated water sources and 2.2 million annual deaths resulting from…
(more)
▼ Waterborne pathogens are a global health concern, with 1 billion people having no access to uncontaminated water sources and 2.2 million annual deaths resulting from infection. Biosensors offer the possibility of rapid, sensitive and specific detection of pathogens and, thus, the ability to provide warning systems prior to consumption and a means to monitor the efficacy of disinfection systems. However, in order for biosensors to be useful, one must be able to attain clinically relevant detection limits in real environmental samples and do so on a reasonable timescale. Thus, methods to increase the analytical sensitivity via pre-concentration and microfluidic device design are described herein. Firstly, employing a series of pre-concentration and purification steps followed by an enzymatic amplification of an mRNA sequence, it is shown that a limit of detection of one Cryptosporidium parvum oocyst can be attained and that this assay does work in real water samples. Secondly, integrating a liposome-based immunoassay and a nanoporous membrane for electrokinetic pre-concentration into a single microfluidic device for the detection of a human norovirus surrogate yielded an order-of-magnitude decrease in the limit of detection when compared to an optimized device foregoing pre-concentration. Finally, the optimization of microfluidic channel dimensions for assays using liposomal signal amplification is described; illustrating that a 60% reduction in channel height produces an order-of-magnitude reduction in the limit of detection. Taken together, the described work provides tools to advance the field of biosensors by demonstrating means to improve analytical sensitivity and overcome the obstacles presented by environmental water samples.
Advisors/Committee Members: Baeumner, Antje J (chair), Weiland, Gregory Arthur (committee member), Durst, Richard A (committee member).
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APA (6th Edition):
Connelly, J. (2011). Bioanalytical Microsystems For Waterborne Pathogen Detection. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/30675
Chicago Manual of Style (16th Edition):
Connelly, John. “Bioanalytical Microsystems For Waterborne Pathogen Detection.” 2011. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/30675.
MLA Handbook (7th Edition):
Connelly, John. “Bioanalytical Microsystems For Waterborne Pathogen Detection.” 2011. Web. 13 Apr 2021.
Vancouver:
Connelly J. Bioanalytical Microsystems For Waterborne Pathogen Detection. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/30675.
Council of Science Editors:
Connelly J. Bioanalytical Microsystems For Waterborne Pathogen Detection. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/30675
Cornell University
5.
Yu, Jiajie.
Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia.
Degree: PhD, Agricultural and Biological Engineering, 2013, Cornell University
URL: http://hdl.handle.net/1813/33881
► In vitro models of human small intestine play a critical role in predicting oral drug absorption efficiency as well as understanding intestinal epithelia functionality. Conventional…
(more)
▼ In vitro models of human small intestine play a critical role in predicting oral drug absorption efficiency as well as understanding intestinal epithelia functionality. Conventional 2D in vitro models fail to represent small intestinal villi which are important 3D features for the small intestinal microenvironment. Without these features, in vitro models of the small intestine lack physiological relevance. By using microfabrication techniques, we created a plastic template with accurate dimensions and densities of human small intestinal villi. Based on this template, we fabricated collagen villous scaffolds utilizing a sacrificial hydrogel technique. By integrating collagen villous scaffolds into a custom designed insert kit, we developed the first 3D in vitro model of the human small intestine. Epithelial cells cultured on this 3D model presented unique cell differentiation morphology similar to human small intestine epithelia. Drug permeability tests conducted on this 3D model provided more accurate results for drugs absorbed through the paracellular pathway when compared to conventional 2D models. In addition, alternative biomaterials were tested for their potential in making 3D villous scaffolds. This work suggests that the 3D in vitro model of the human small intestine is an effective tool for predicting drug permeability as well as investigating the small intestinal microenvironment.
Advisors/Committee Members: March, John C (chair), Luo, Dan (committee member), Baeumner, Antje J (committee member).
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APA (6th Edition):
Yu, J. (2013). Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/33881
Chicago Manual of Style (16th Edition):
Yu, Jiajie. “Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia.” 2013. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/33881.
MLA Handbook (7th Edition):
Yu, Jiajie. “Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia.” 2013. Web. 13 Apr 2021.
Vancouver:
Yu J. Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia. [Internet] [Doctoral dissertation]. Cornell University; 2013. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/33881.
Council of Science Editors:
Yu J. Towards Making A Better In Vitro Model Of Human Upper Gastrointestinal Tract Epithelia. [Doctoral Dissertation]. Cornell University; 2013. Available from: http://hdl.handle.net/1813/33881
Cornell University
6.
Kondapalli, Sowmya.
Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection.
Degree: PhD, Mechanical Engineering, 2011, Cornell University
URL: http://hdl.handle.net/1813/29486
► In this work, we present two different applications of microfluidic control. In the first application, we have developed a microfluidic device that has the potential…
(more)
▼ In this work, we present two different applications of microfluidic control. In the first application, we have developed a microfluidic device that has the potential to automate combinatorial protocols like protein refolding, impacting the biopharmaceutical industry. This device uses microfluidic valves and pumps that can be operated in an automated fashion for fluidic control. We performed refolding experiments on the protein [beta]-galactosidase and showed on-chip quantification of refolding yield using a fluorometric assay. In the second application, we have developed a microfluidic immunobiosensor with an integrated preconcentration system to improve the detection sensitivity. A nanoporous membrane fabricated in-situ using photopolymerization technique inside glass microchannels acts as the preconcentration system. Analytes were electrophoretically concentrated at the membrane and the concentrated bolus was eluted towards a detection region downstream. We performed proof-of-principle experiments using biotin-streptavidin binding to show the improvement in detection sensitivity of this device as opposed to a device that does not include a preconcentration system. Using this device, we also showed a detection limit of 1.6 X 105 PFU/ml for Feline Calicivirus (FCV), which is a model system for human enteric virus. This device has potential to serve as an early detection system for such enteric viruses in environmental water samples.
Advisors/Committee Members: Kirby, Brian (chair), Baeumner, Antje J (committee member), Collins, Lance (committee member).
Subjects/Keywords: Microfluidic devices; Combinatorial protein refolding; Biosensors for virus detection
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APA (6th Edition):
Kondapalli, S. (2011). Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/29486
Chicago Manual of Style (16th Edition):
Kondapalli, Sowmya. “Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection.” 2011. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/29486.
MLA Handbook (7th Edition):
Kondapalli, Sowmya. “Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection.” 2011. Web. 13 Apr 2021.
Vancouver:
Kondapalli S. Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/29486.
Council of Science Editors:
Kondapalli S. Development Of Microfluidic Devices For Biopharmaceutical Production And Biotoxin Detection. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/29486
Cornell University
7.
Matlock-Colangelo, Lauren.
Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems.
Degree: PhD, Agricultural and Biological Engineering, 2015, Cornell University
URL: http://hdl.handle.net/1813/40671
► Microfluidic biosensors which incorporate both sample preparation and analyte detection, also referred to as lab-on-a-chip (LOC) devices, are a promising means of providing low cost,…
(more)
▼ Microfluidic biosensors which incorporate both sample preparation and analyte detection, also referred to as lab-on-a-chip (LOC) devices, are a promising means of providing low cost, rapid, and portable analyte detection in point-of-care, rural, and developing world applications1- 3 . However, despite numerous reports of LOC devices capable of detecting a range of clinical analytes1-3, there are several key challenges that face the development of true LOC devices. First, due to the small size of these miniaturized systems, it is often necessary to significantly concentrate the sample volume to the nL-[MICRO SIGN]L range 4. Additionally, samples must be purified to remove particulates and impurities that may impede analyte detection. Finally, fluid flow in microfluidic devices is generally laminar, which limits the amount of fluid mixing that occurs within the channels5-7. Because rapid fluid mixing is typically required to facilitate chemical reactions and ensure access of analytes to functional surfaces within the microchannels, micromixers need to be incorporated into the design of a LOC device. This research aims to address the need for both better sample preparation and fluid mixing within microfluidic assays through the use of functionalized electrospun nanofibers. Electrospinning is a fiber formation process in which electrical forces are used to form ultrathin fibers from viscous polymer spinning solutions8. The nonwoven fiber mats produced during electrospinning are characterized by extremely large surface-area-to-volume ratios and high porosities. Additionally, electrospun nanofibers can easily be functionalized either through the inclusion of nanoscale materials into the polymer spinning dope, or through post-spinning modifications. In this work, positively and negatively charged poly(vinyl alcohol) (PVA) nanofibers were created through the addition of hexadimethrine bromide (polybrene) and poly(methyl vinyl ether-alt-maleic anhydride) (poly(MVE/MA), respectively, into a 10% w/v PVA spinning solution. Additionally, larger diameter polystyrene (PS) microfibers with a range of morphologies were spun using 12.5, 15, and 17% w/v PS spinning solutions. Previously, gold microelectrodes patterned onto poly(methyl methacrylate) (PMMA) were used to incorporate the nanofibers into microfluidic channels9,10. However, in this work, fibers were bonded into microchannels without the use of a gold electrode, resulting in simple, inexpensive device fabrication. Both PVA and PS fibers were spun onto metal collector plates and manually transferred to pieces of PMMA that had undergone UV-Ozone treatment. In order to produce nanofiber mats with uniform fiber distributions along their height, thin nanofiber mats were stacked together to create multilayered mats 11,12. Positively charged PVA mats were shown to successfully bind and concentrate E. coli cells, while negatively charged PVA mats repelled the cells and were used to minimize nonspecific retention within the channels. The 3D morphology of the PVA nanofiber mats was…
Advisors/Committee Members: Baeumner,Antje J (chair), Kirby,Brian (committee member), Frey,Margaret W (committee member).
Subjects/Keywords: Biosensing; Electrospun Nanofibers; Microfluidics
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APA ·
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APA (6th Edition):
Matlock-Colangelo, L. (2015). Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/40671
Chicago Manual of Style (16th Edition):
Matlock-Colangelo, Lauren. “Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems.” 2015. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/40671.
MLA Handbook (7th Edition):
Matlock-Colangelo, Lauren. “Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems.” 2015. Web. 13 Apr 2021.
Vancouver:
Matlock-Colangelo L. Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems. [Internet] [Doctoral dissertation]. Cornell University; 2015. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/40671.
Council of Science Editors:
Matlock-Colangelo L. Functionalized Electrospun Nanofibers For Sample Preparation And Analyte Detection In Microfluidic Bioanalytical Systems. [Doctoral Dissertation]. Cornell University; 2015. Available from: http://hdl.handle.net/1813/40671
Cornell University
8.
Hendrick, Erin.
Stimuli-Responsive Electrospun Fibers.
Degree: PhD, Fiber Science, 2011, Cornell University
URL: http://hdl.handle.net/1813/30649
► Stimuli-responsive fibers were created by incorporating pH-sensitive nanoparticles into electrospun cellulose acetate (CA) and poly(lactic acid) (PLA) fibers. The fluorescent silica nanoparticles, Cornell dots (C…
(more)
▼ Stimuli-responsive fibers were created by incorporating pH-sensitive nanoparticles into electrospun cellulose acetate (CA) and poly(lactic acid) (PLA) fibers. The fluorescent silica nanoparticles,
Cornell dots (C dots), have both a fluorescent core (518 nm emission), and a fluorescent pH-sensitive shell (572 nm emission). Using confocal microscopy, the signaling effectiveness of these fibers was studied by varying several parameters: fiber diameter, substrate, and surface hydrophilicity. For the CA fibers, fiber diameter was varied by changing the feed rate during the electrospinning process to 0.03 mL/hr, 0.30 mL/hr and 0.30 mL/min, producing fibers with average diameters of 1.1 [MICRO SIGN]m, 1.8 [MICRO SIGN]m and 9.5 [MICRO SIGN]m, respectively. It was found that fibers with larger surface area had a greater sensitivity to pH change than fibers with smaller surface area. The response of the pH-sensitive fibers also varied when both the nanoparticles and CA fibers were applied/electrospun onto the surface of four different substrates: optical glass slides, cotton, cotton/polyester, and nylon/spandex fabrics. Fibers spun onto glass slides and cotton/polyester showed an improvement in sensitivity to pH change, while the cotton and nylon/spandex samples were greatly influenced by the chemistry inherent to these substrates. Poly(lactic acid) - b - poly(ethylene glycol) (PLA-b-PEG) copolymers with block lengths of 1000-750, 5000-1000 and 1000-5000 and bulk PEG were added to PLA electrospinning dopes to create hydrophilic but non-water soluble nanofibers. PLA-b-PEG block lengths strongly affected the total amount of PEG that could be incorporated, spinnability and fiber morphology. Solutions containing >1% w/w of the lowest molecular weight copolymer PLA (1000) - b - PEG (750) formed an unspinnable, cloudy gel. Addition of the PLA (5000) - b - PEG (1000) to the base spinning solution influenced fiber diameters and spinnability in the same manner as simply increasing PLA concentration in the spinning dope. Addition of PLA (1000) - b - PEG (5000) resulted in decreased fiber diameters, and allowed for the highest overall copolymer loading. In final fiber formulations, maximums of 0.9, 2.9 and 9.3 wt% PEG could be added to the fibers using the PLA-b-PEG 1000-750, 5000-1000 and 1000-5000 respectively. PEG (MW = 3350 g/mol) homopolymer was added to the spinning dopes to result in 1.0 and 5.0 wt% PEG in the final fibers. These spinning dopes were electrospun with more non-uniform and variable morphology and diameter size than occurred with the addition of PEG in block copolymer form. Water absorbance by electrospun nonwoven fabrics increased by four times over the control PLA with the addition of 1.0 wt% PEG, and by eighteen times with the addition of 9.3 wt% PEG with the block copolymers. At similar overall PEG loadings, the addition of PLA-b-PEG resulted in a two to four fold increase in water wicking over the addition of PEG homopolymer. The improvement in water wicking was mirrored in the pH-measurement data compiled for…
Advisors/Committee Members: Frey, Margaret W (chair), Baeumner, Antje J (committee member), Wiesner, Ulrich B. (committee member).
Subjects/Keywords: Electrospinning; pH sensing; Wettability
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APA (6th Edition):
Hendrick, E. (2011). Stimuli-Responsive Electrospun Fibers. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/30649
Chicago Manual of Style (16th Edition):
Hendrick, Erin. “Stimuli-Responsive Electrospun Fibers.” 2011. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/30649.
MLA Handbook (7th Edition):
Hendrick, Erin. “Stimuli-Responsive Electrospun Fibers.” 2011. Web. 13 Apr 2021.
Vancouver:
Hendrick E. Stimuli-Responsive Electrospun Fibers. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/30649.
Council of Science Editors:
Hendrick E. Stimuli-Responsive Electrospun Fibers. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/30649
Cornell University
9.
Cordovez, Bernardo.
Electrokinetically Active Nanowells.
Degree: PhD, Mechanical Engineering, 2011, Cornell University
URL: http://hdl.handle.net/1813/29228
► In this research I developed a new form of microfluidic transport technique that exploits electrokinetic phenomena in discrete micro and nanometer sized wells. Through the…
(more)
▼ In this research I developed a new form of microfluidic transport technique that exploits electrokinetic phenomena in discrete micro and nanometer sized wells. Through the use of these "Electroactive Nanowells", I have been able to demonstrate the reversible trapping of micro and nanoscale objects in discrete locations, enabled a new form of microfluidic memory and used a modified version of this technique to generate a wireless drug delivery system for the control of flying insects. The outcome of this research is threefold: First, it establishes a low power device that can increase the speed of traditional microwell screening techniques by four orders of magnitude in an easy to fabricate setup. The second outcome is the development of the first high density microfluidic memory, which can store up to 6 bits of material storage in single 200 nanometer wells; providing a 6 order magnitude increase in storage density over traditional microfluidic storage devices. Third, I exploited the essential transport physics of this approach to enable a wireless and implantable drug delivery system capable of dispensing various chemicals on demand; and applied it to the of chemically directed control of live micro air vehicles. Fourth, I present a flexible version of this drug delivery system by using only polymers in the fabrication process.
Advisors/Committee Members: Erickson, David (chair), Kan, Edwin Chihchuan (committee member), Baeumner, Antje J (committee member).
Subjects/Keywords: microfluidics; optofluidics
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APA (6th Edition):
Cordovez, B. (2011). Electrokinetically Active Nanowells. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/29228
Chicago Manual of Style (16th Edition):
Cordovez, Bernardo. “Electrokinetically Active Nanowells.” 2011. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/29228.
MLA Handbook (7th Edition):
Cordovez, Bernardo. “Electrokinetically Active Nanowells.” 2011. Web. 13 Apr 2021.
Vancouver:
Cordovez B. Electrokinetically Active Nanowells. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/29228.
Council of Science Editors:
Cordovez B. Electrokinetically Active Nanowells. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/29228
Cornell University
10.
Nitkowski, Arthur.
Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices.
Degree: PhD, Applied Physics, 2011, Cornell University
URL: http://hdl.handle.net/1813/29213
► The devices fabricated and explored in this thesis belong to an emergent research field referred to as optofluidics. Research innovations in the areas of integrated…
(more)
▼ The devices fabricated and explored in this thesis belong to an emergent research field referred to as optofluidics. Research innovations in the areas of integrated optics and microfluidics have brought forth this new and exciting area of study which combines photonics with fluid handling on the microscale. By taking advantage of tools designed for the microelectronics industry, optofluidics promises new innovations which may revolutionize the areas of diagnostic medicine, drug discovery, and environmental monitoring. In this thesis, I have explored how one of the main building blocks of photonics-the optical cavity- can be combined with microfluidic handling capabilities to perform spectroscopic measurements for life science applications. This dissertation is divided into seven chapters with the following organization. In Chapter 1, I introduce the research field of optofluidics and its application in lab-on-a-chip technologies. Chapter 2 includes a motivation for the use of optical microcavities in biomedical sensing applications. I discuss the relevant parameters which describe the behavior of microring resonators and derive the equations governing their operation. Chapter 3 describes an experiment where polystyrene microspheres were optically trapped by the evanescent field from high index contrast silicon nitride waveguides. The use of a high-power broadband light source enables the simultaneous trapping, transport, and characterization of these microspheres by using their resonant properties. Chapter 4 discusses the use of optical microcavities to perform integrated laser absorption spectroscopy on nanoliter volumes of fluid. Relying on the cavity enhancement of light by silicon microrings, I demonstrate a sensitive and compact device which measures optical absorption in the near infrared regime. In Chapter 5 I demonstrate spectrophotometry measurements at visible wavelengths using microring resonators. Absorption products catalyzed by enzymes commonly used in bioassays are measured with microring resonator sensitive to the activity of individual enzymes. Chapter 6 builds on the work of the previous chapters to demonstrate microring measurements of optical absorption generated by bacteria growth. Results show the platform can be useful for fundamental studies on single bacteria. The final chapter includes a summary of the work and an outlook on the future of lab-on-a-chip devices.
Advisors/Committee Members: Lipson, Michal (chair), Baeumner, Antje J (committee member), Pollack, Lois (committee member).
Subjects/Keywords: nanophotonics; microfluidics; microcavity; integrated optics; absorption spectroscopy; lab-on-a-chip
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APA ·
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APA (6th Edition):
Nitkowski, A. (2011). Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/29213
Chicago Manual of Style (16th Edition):
Nitkowski, Arthur. “Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices.” 2011. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/29213.
MLA Handbook (7th Edition):
Nitkowski, Arthur. “Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices.” 2011. Web. 13 Apr 2021.
Vancouver:
Nitkowski A. Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices. [Internet] [Doctoral dissertation]. Cornell University; 2011. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/29213.
Council of Science Editors:
Nitkowski A. Cavity-Enhanced Nanophotonic Spectroscopy In Optofluidic Devices. [Doctoral Dissertation]. Cornell University; 2011. Available from: http://hdl.handle.net/1813/29213
Cornell University
11.
Jung, Eunjung.
Optofluidic Approches In Reconfigurable Photonics And Renewable Energy.
Degree: PhD, Mechanical Engineering, 2013, Cornell University
URL: http://hdl.handle.net/1813/34235
► The theme of my Ph.D. research is to apply optofluidics to solve problems in interdisciplinary areas, specifically reconfigurable photonics and photobioreactors for microalgae based biofuel…
(more)
▼ The theme of my Ph.D. research is to apply optofluidics to solve problems in interdisciplinary areas, specifically reconfigurable photonics and photobioreactors for microalgae based biofuel production. In the first part of the dissertation, I have developed a hybrid reconfigurable photonic system that combines liquid and solid state optical waveguides on a chip. The hybrid system was numerically and experimentally investigated. The apparatus allowed us to take advantages of liquidstate optical elements, such as chemical adaptability, thermal stabilization, and physical tunability, without sacrificing the performance offered by solid-state optical devices. This novel approach represents a potentially transformative advancement for reconfigurable photonic systems. In the second part of the dissertation, I have developed optofluidic photobioreactors that incorporate photonic elements to solve problems in current photobioreactors for algae biofuel production. I first demonstrated and characterized photosynthetic growth in the evanescent field of a slab waveguide. The bacterial growth has been further demonstrated in a 10 stack waveguide photobioreactor. This novel optofluidic photobioreactor increases the culture density that can result in cost-effective bioreactors with lower operational costs and reduced water and energy consumption.
Advisors/Committee Members: Erickson, David (chair), Baeumner, Antje J (committee member), Pollock, Clifford Raymond (committee member).
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APA (6th Edition):
Jung, E. (2013). Optofluidic Approches In Reconfigurable Photonics And Renewable Energy. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/34235
Chicago Manual of Style (16th Edition):
Jung, Eunjung. “Optofluidic Approches In Reconfigurable Photonics And Renewable Energy.” 2013. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/34235.
MLA Handbook (7th Edition):
Jung, Eunjung. “Optofluidic Approches In Reconfigurable Photonics And Renewable Energy.” 2013. Web. 13 Apr 2021.
Vancouver:
Jung E. Optofluidic Approches In Reconfigurable Photonics And Renewable Energy. [Internet] [Doctoral dissertation]. Cornell University; 2013. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/34235.
Council of Science Editors:
Jung E. Optofluidic Approches In Reconfigurable Photonics And Renewable Energy. [Doctoral Dissertation]. Cornell University; 2013. Available from: http://hdl.handle.net/1813/34235
Cornell University
12.
Gumus, Abdurrahman.
Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics.
Degree: PhD, Electrical Engineering, 2015, Cornell University
URL: http://hdl.handle.net/1813/39295
► The field of bioelectronics started about 18th century with the frog experiments of Luigi Galvani by moving the detached leg of frog with the application…
(more)
▼ The field of bioelectronics started about 18th century with the frog experiments of Luigi Galvani by moving the detached leg of frog with the application of a small voltage. Today there are variety of bioelectronic devices available in many different areas such as pacemakers, continuous glucose sensors, implantable brain tissue interfaces, that show how far we have gone since the Galvani experiments. This dissertation introduces bioelectronic systems for different research areas such as tissue engineering, biophysical monitoring of birds and point-of-care diagnostics. First, we have introduced a device depends on organic bioelectronics, a growing research field that integrates organic electronic materials with biological systems, and used it for tissue engineering purposes. We have developed a planar device that contains a conducting polymer stripe and achieves a continuum of microenvironments for cell growth under the influence of an applied bias. Marked differences are observed in the migration behaviors of bovine aortic endothelial cells (EC) as a function of location along the polymer stripe, and 3-fold variation is achieved in EC migration speed and directional persistence time. A gradient in adsorbed fibronectin indicates that a spatial variation in cell adhesion is at play. We have used our device to modulate the cell adhesion and changed cell density gradients of normal and cancerous cell lines by inducing electrically which can be used as a tool for the study of cell-cell interactions. Next, we have developed a real-time in vivo uric acid biosensor system, Labon-a-Bird, for biophysical monitoring of birds. The metabolism of birds is finely tuned to their activities and environments, and thus research on avian systems can play an important role in understanding organismal responses to environmental changes and ecological investigations. After characterization of the sensor system, we demonstrated the autonomous operation of the system by collecting in vivo extracellular uric acid measurements on a domestic chicken. We then show how the device can be used to monitor, in real time, the effects of short-term flight and rest cycles on the uric acid levels of pigeons. In addition, we demonstrate that our device has the ability to measure uric acid level increase in homing pigeons while they fly freely to back home. Successful application of the sensor in migratory birds could open up a new way of studying birds in flight which would lead to a better understanding of the ecology and biology of avian movements. Finally, we have presented a Cholera-Detect system for point-of-care detection of Vibrio Cholerae which is a comma-shaped, gram negative bacterium and the cause of an acute diarrhoeal disease in humans called "Cholera". Even though up to 80% of the cases can be successfully treated with oral rehydration salts, around 100,000 - 120,000 of the cases come to an end as deaths. This indicates that early and rapid detection of the cholera is necessary to prevent spread of disease, increase the efficiency of…
Advisors/Committee Members: Erickson, David (chair), Manohar, Rajit (committee member), Winkler, David Ward (committee member), Baeumner, Antje J (committee member).
Subjects/Keywords: Bioelectronics; Biophysical monitoring; Point-of-care diagnostics
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APA ·
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Export
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APA (6th Edition):
Gumus, A. (2015). Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/39295
Chicago Manual of Style (16th Edition):
Gumus, Abdurrahman. “Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics.” 2015. Doctoral Dissertation, Cornell University. Accessed April 13, 2021.
http://hdl.handle.net/1813/39295.
MLA Handbook (7th Edition):
Gumus, Abdurrahman. “Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics.” 2015. Web. 13 Apr 2021.
Vancouver:
Gumus A. Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics. [Internet] [Doctoral dissertation]. Cornell University; 2015. [cited 2021 Apr 13].
Available from: http://hdl.handle.net/1813/39295.
Council of Science Editors:
Gumus A. Bioelectronic Systems In Studying Tissue Engineering, Real-Time Biophysical Monitoring Of Birds And Point-Of-Care Diagnostics. [Doctoral Dissertation]. Cornell University; 2015. Available from: http://hdl.handle.net/1813/39295
. 
Open Access Theses and Dissertations