R-3 Repository :: Browsing by Author "Christodoulides, Nicolaos"

Browsing by Author "Christodoulides, Nicolaos"

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Application of programmable bio-nano-chip system for the quantitative detection of drugs of abuse in oral fluids
(Elsevier, 2015) Christodoulides, Nicolaos; De La Garza, Richard II; Simmons, Glennon W.; McRae, Michael P.; Wong, Jorge; Newton, Thomas F.; Smith, Regina; Mahoney, James J. III; Hohenstein, Justin; Gomez, Sobeyda; Floriano, Pierre N.; Talavera, Humberto; Sloan, Daniel J.; Moody, David E.; Andrenyak, David M.; Kosten, Thomas R.; Haque, Ahmed; McDevitt, John T.
Objective: There is currently a gap in on-site drug of abuse monitoring. Current detection methods involve invasive sampling of blood and urine specimens, or collection of oral fluid, followed by qualitative screening tests using immunochromatographic cartridges. While remote laboratories then may provide confirmation and quantitative assessment of a presumptive positive, this instrumentation is expensive and decoupled from the initial sampling making the current drug-screening program inefficient and costly. The authors applied a noninvasive oral fluid sampling approach integrated with the in-development chip-based Programmable bio-nano-chip (p-BNC) platform for the detection of drugs of abuse. Method: The p-BNC assay methodology was applied for the detection of tetrahydrocannabinol, morphine, amphetamine, methamphetamine, cocaine, methadone and benzodiazepines, initially using spiked buffered samples and, ultimately, using oral fluid specimen collected from consented volunteers. Results: Rapid (∼10 min), sensitive detection (∼ng/mL) and quantitation of 12 drugs of abuse was demonstrated on the p-BNC platform. Furthermore, the system provided visibility to time-course of select drug and metabolite profiles in oral fluids; for the drug cocaine, three regions of slope were observed that, when combined with concentration measurements from this and prior impairment studies, information about cocaine-induced impairment may be revealed. Conclusions: This chip-based p-BNC detection modality has significant potential to be used in the future by law enforcement officers for roadside drug testing and to serve a variety of other settings, including outpatient and inpatient drug rehabilitation centers, emergency rooms, prisons, schools, and in the workplace.
Bio-nano-chips for on-site drug screening
(2017-07-18) McDevitt, John T.; Christodoulides, Nicolaos; Floriano, Pierre N.; Simmons, Glennon; Rice University; United States Patent and Trademark Office
A bio-nano-chip (BNC) technology that works in connection with non-invasive samples, such as saliva, cheek swab or urine samples that can be easily performed by non-specialists, such as security personnel and police officers is disclosed. The microfluidic system for drug testing includes an analyzer or reader having a housing containing a slot for receiving a cartridge, a drug testing cartridge, a processor having a user interface, an optical or energy sensing means, and a means for moving fluid.
Enhancement of performance in porous bead-based microchip sensors: effects of chip geometry on bio-agent capture
(Royal Society of Chemistry, 2015) Kulla, Eliona; Chou, Jie; Simmons, Glennon; Wong, Jorge; McRae, Michael P.; Patel, Rushi; Floriano, Pierre N.; Christodoulides, Nicolaos; Leach, Robin J.; Thompson, Ian M.; McDevitt, John T.
Measuring low concentrations of clinically-important biomarkers using porous bead-based lab-on-a-chip (LOC) platforms is critical for the successful implementation of point-of-care (POC) devices. One way to meet this objective is to optimize the geometry of the bead holder, referred to here as a micro-container. In this work, two geometric micro-containers were explored, the inverted pyramid frustum (PF) and the inverted clipped pyramid frustum (CPF). Finite element models of this bead array assay system were developed to optimize the micro-container and bead geometries for increased pressure, to increase analyte capture in porous bead-based fluorescence immunoassays. Custom micro-milled micro-container structures containing an inverted CPF geometry resulted in a 28% reduction in flow-through regions from traditional anisotropically-etched pyramidal geometry derived from Si-111 termination layers. This novel "reduced flow-through" design resulted in a 33% increase in analyte penetration into the bead and twofold increase in fluorescence signal intensity as demonstrated with C-Reactive Protein (CRP) antigen, an important biomarker of inflammation. A consequent twofold decrease in the limit of detection (LOD) and the limit of quantification (LOQ) of a proof-of-concept assay for the free isoform of Prostate-Specific Antigen (free PSA), an important biomarker for prostate cancer detection, is also presented. Furthermore, a 53% decrease in the bead diameter is shown to result in a 160% increase in pressure and 2.5-fold increase in signal, as estimated by COMSOL models and confirmed experimentally by epi-fluorescence microscopy. Such optimizations of the bead micro-container and bead geometries have the potential to significantly reduce the LODs and reagent costs for spatially programmed bead-based assay systems of this type.
Hot embossed polyethylene through-hole chips for bead-based microfluidicdevices
(Elsevier, 2013) Chou, Jie; Du, Nan; Ou, Tina; Floriano, Pierre N.; Christodoulides, Nicolaos; McDevitt, John T.; Rice Quantum Institute
Over the past decade, there has been a growth of interest in the translation of microfluidic systems into real-world clinical practice, especially for use in point-of-care or near patient settings. While initial fabrication advances in microfluidics involved mainly the etching of silicon and glass, the economics of scaling of these materials is not amendable for point-of-care usage where single-test applications forces cost considerations to be kept low and throughput high. As such, a materials base more consistent with point-of-care needs is required. In this manuscript, the fabrication of a hot embossed, through-hole low-density polyethylene ensembles derived from an anisotropically etched silicon wafer is discussed. This semi-opaque polymer that can be easily sterilized and recycled provides low background noise for fluorescence measurements and yields more affordable cost than other thermoplastics commonly used for microfluidic applications such as cyclic olefin copolymer (COC). To fabrication through-hole microchips from this alternative material for microfluidics, a fabrication technique that uses a high-temperature, high-pressure resistant mold is described. This aluminum-based epoxy mold, serving as the positive master mold for embossing, is casted over etched arrays of pyramidal pits in a silicon wafer. Methods of surface treatment of the wafer prior to casting and PDMS casting of the epoxy are discussed to preserve the silicon wafer for future use. Changes in the thickness of polyethylene are observed for varying embossing temperatures. The methodology described herein can quickly fabricate 20 disposable, single use chips in less than 30 minutes with the ability to scale up 4x by using multiple molds simultaneously. When coupled as a platform supporting porous bead sensors, as in the recently developed Programmable Bio-Nano-Chip, this bead chip system can achieve limits of detection, for the cardiac biomarker C-reactive protein, of 0.3 ng/mL, thereby demonstrating the approach is compatible with high performance, real-world clinical measurements in the context of point-of-care testing.
Multisample bionanochip platform
(2016-02-02) McDevitt, John; Christodoulides, Nicolaos; Floriano, Pierre N.; Abram, Tim; Rice University; United States Patent and Trademark Office
A bionanochip cartridge for analysis of multiple samples or analytes is provided herein, and the cartridge is dimensioned to take advantage of existing robotic microtiter plate handling equipment. Fluidics are specially designed to provide a small footprint and to prevent cross contamination.
Oral cancer point of care diagnostics
(2017-01-03) McDevitt, John T.; Christodoulides, Nicolaos; Floriano, Pierre N.; Thornhill, Martin; Redding, Spencer; Vigneswaran, Nadarajah; Murdoch, Craig; Speight, Paul; Rice University; United States Patent and Trademark Office
A point of care diagnostic test, device and disposables for determining a patient risk for oral cancer in the same visit that a sample is collected.
Porous Bead-Based Diagnostic Platforms: Bridging the Gaps in Healthcare
(MPDI, 2012) Chou, Jie; Wong, Jorge; Christodoulides, Nicolaos; Floriano, Pierre N.; Sanchez, Ximena; McDevitt, John
Advances in lab-on-a-chip systems have strong potential for multiplexed detection of a wide range of analytes with reduced sample and reagent volume; lower costs and shorter analysis times. The completion of high-fidelity multiplexed and multiclass assays remains a challenge for the medical microdevice field; as it struggles to achieve and expand upon at the point-of-care the quality of results that are achieved now routinely in remote laboratory settings. This review article serves to explore for the first time the key intersection of multiplexed bead-based detection systems with integrated microfluidic structures alongside porous capture elements together with biomarker validation studies. These strategically important elements are evaluated here in the context of platform generation as suitable for near-patient testing. Essential issues related to the scalability of these modular sensor ensembles are explored as are attempts to move such multiplexed and multiclass platforms into large-scale clinical trials. Recent efforts in these bead sensors have shown advantages over planar microarrays in terms of their capacity to generate multiplexed test results with shorter analysis times. Through high surface-to-volume ratios and encoding capabilities; porous bead-based ensembles; when combined with microfluidic elements; allow for high-throughput testing for enzymatic assays; general chemistries; protein; antibody and oligonucleotide applications.
Programmable bio-nano-chip system: a flexible point-of-care platform for bioscience and clinical measurements
(Royal Society of Chemistry, 2015) McRae, Michael P.; Simmons, Glennon W.; Wong, Jorge; Shadfan, Basil; Gopalkrishnan, Sanjiv; Christodoulides, Nicolaos; McDevitt, John T.
The development of integrated instrumentation for universal bioassay systems serves as a key goal for the lab-on-a-chip community. The programmable bio-nano-chip (p-BNC) system is a versatile multiplexed and multiclass chemical- and bio-sensing system for bioscience and clinical measurements. The system is comprised of two main components, a disposable cartridge and a portable analyzer. The customizable single-use plastic cartridges, which now can be manufactured in high volumes using injection molding, are designed for analytical performance, ease of use, reproducibility, and low cost. These labcard devices implement high surface area nano-structured biomarker capture elements that enable high performance signaling and are index-matched to real-world biological specimens. This detection modality, along with the convenience of on-chip fluid storage in blisters and self-contained waste, represents a standard process to digitize biological signatures at the point-of-care. A companion portable analyzer prototype has been developed to integrate fluid motivation, optical detection, and automated data analysis, and it serves as the human interface for complete assay automation. In this report, we provide a systems-level perspective of the p-BNC universal biosensing platform with an emphasis on flow control, device integration, and automation. To demonstrate the flexibility of the p-BNC, we distinguish diseased and non-case patients across three significant disease applications: prostate cancer, ovarian cancer, and acute myocardial infarction. Progress towards developing a rapid 7 minute myoglobin assay is presented using the fully automated p-BNC system.
Prostate cancer point of care diagnostics
(2017-06-06) McDevitt, John T.; Christodoulides, Nicolaos; Floriano, Pierre N.; Thompson, Ian; Rice University; United States Patent and Trademark Office
The invention relates to point of care diagnostic disposables, devices, methods, and systems for diagnosing or predicting prostate cancer. The present invention employs biomarker specific reagents in disposable cassettes or lab cards for use as analyzers, as well as software to evaluate and report test results. The system promises to improve point of care in vitro diagnostics.

Browsing by Author "Christodoulides, Nicolaos"

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