Development of a fluorescence resonance energy transfer optical nanoscale biosensor based on a liquid-core waveguide platform

The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file.Title from title screen of research.pdf file (viewed on September 30, 2008)Includes bibliographical references.Thesis (M.S.) University of Missouri-Columbia 2007.Dissertations, Academic -- University of Missouri--Columbia -- Biological engineering.In order to produce a more versatile, adaptable, and effective method for detection of biological analytes, a self-contained and robust fluorescent optical biosensor architecture utilizing fluorescence resonance energy transfer (FRET) is proposed. This biosensor architecture is then applied to a highly adept liquid-core waveguide platform. FRET is a distance-dependent signal transduction method that occurs between two fluorescent molecules, termed the donor and acceptor. When the donor and acceptor are brought within close proximity, a quantifiable nonradiative energy exchange takes place. In order to launch FRET, a donor-labeled Protein A molecule is bound to an acceptor-labeled capture antibody. When exposed to antigen, the antibody-antigen binding event initiates a conformational change within the structure of the antibody, and thereby induces a measurable change in energy transfer from the donor to the acceptor by altering the distance between the FRET pair. Additionally, effects of quantum dots and gold nanoparticles utilized within the FRET system are studied. The resulting system is then optimized and tested in a liquid-core waveguide platform that is able to retrieve sensitive and accurate measurements. In the current study, the biosensor was used to detect Porcine Reproductive and Respiratory Syndrome virus and human cardiac Troponin I, showing ample sensitivity and a high degree of specificity, as well as rapid response

Molecularly imprinted polymer labeled with quantum dots for detection of nitroaromatic explosives

Title from PDF of title page (University of Missouri--Columbia, viewed on December 7, 2010).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Dissertation advisor: Dr. Sheila A. Grant and Dr. Shubhra Gangopadhyay.Vita.Ph. D. University of Missouri--Columbia 2010.A sensing device for explosive compounds is a fundamental step towards the capability to detect the presence of landmines, improvised explosive devices (IEDs), and other unexploded ordinance. To detect high explosive compounds such as 2,4,6-trinitrotoluene (TNT), an optical sensor utilizing molecularly imprinted polymer (MIP) technology was developed. This sensor consists of MIP microparticles prepared using methacrylic acid as the functional monomer in a precipitation polymerization reaction. The MIP particles are combined with fluorescent semiconductor nanocrystals, or quantum dots, via a simple crosslinking procedure. The MIP is then capable of rebinding the explosive compound, which quenches the fluorescence of the covalently linked quantum dots. After preliminary studies of the basic sensing mechanism, a precipitation polymerization reaction was used to create MIP particles with a uniform spherical shape and sub-micron size, as well as MIP particles with a porous mesh-like morphology. A comparison study of these two types of particles indicated that the MIP microspheres were more effective at binding the nitroaromatic explosive TNT and its breakdown product 2,4-dinitrotoluene (DNT). The MIP microsphere-based fluorescence sensing scheme was then entrapped into a sol-gel matrix and applied to a solid substrate sensor platform for detection of vapor-phase explosives. However, the detection method showed poor performance and was unsuitable for sensing of airborne nitroaromatic explosive compounds.Includes bibliographical reference

For plantar taping, direction of elasticity matters

Abstract Plantar taping has been used in clinical settings as a short-term conservative treatment for plantar heel pain and related pathologies. The rise of at-home taping methods may offer patients more independence, but effectiveness has not been established. The purpose of this study was to evaluate the effects of plantar taping on foot mechanics during gait. We hypothesized that material compliance would drive mechanical effectiveness, with longitudinally inelastic tape reducing medial longitudinal arch (MLA) motion and anterior/posterior (A/P) plantar tissue spreading forces, and laterally inelastic tape reducing medial/lateral (M/L) tissue spreading. We also hypothesized that these effects would be influenced by foot structure. Fifteen healthy participants were tested in a randomized cross-over study design. Barefoot (BF) plus four taping methods were evaluated, including two inelastic tapes (Low-Dye, LD, and FasciaDerm, FD) along with longitudinally elastic kinesiology tape (KT) and a novel laterally elastic kinesiology tape (FAST, FS). Participants’ arch height and flexibility were measured followed by instrumented gait analysis with a multi-segment foot model. Ankle eversion and MLA drop/rise were calculated from rearfoot and forefoot reference frames, while plantar tissue spreading was calculated from shear stresses. ANOVAs with Holm pairwise tests evaluated tape effects while correlations connected arch structure and taping effectiveness (α = 0.05). The three longitudinally inelastic tapes (LD, FD, FS) reduced MLA drop by 11–15% compared with KT and BF. In late stance, these tapes also inhibited MLA rise (LD by 29%, FD and FS by 10–15%). FS and FD reduced A/P spreading forces, while FD reduced M/L spreading forces compared with all other conditions. Arch height had a moderately strong correlation (r = -0.67) with the difference in MLA drop between BF and FS. At-home plantar taping can affect the mechanical function of the foot, but tape elasticity direction matters. Longitudinally elastic kinesiology tape has little effect on mechanics, while inelastic tapes control MLA drop but also restrict MLA rise in late stance. Lateral elasticity does not limit tissue spreading and may increase comfort without sacrificing MLA control. At-home taping has the potential to broaden conservative treatment of plantar heel pain, flat foot deformity, and related pathologies, but additional studies are needed to connect mechanics with symptom relief

High rates of recombination in otitis media isolates of non-typeable Haemophilus influenzae.

Non-typeable (NT) or capsule-deficient, Haemophilus influenzae (Hi) is a common commensal of the upper respiratory tract of humans and can be pathogenic resulting in diseases such as otitis media, sinusitis and pneumonia. The lipopolysaccharide (LPS) of NTHi is a major virulence factor that displays substantial intra-strain and inter-strain variation of its oligosaccharide structures. To investigate the genetic basis of LPS variation we sequenced internal regions of each of seven genes required for the biosynthesis of either the inner or the outer core oligosaccharide structures. These sequences were obtained from 25 representative NTHi isolates from episodes of otitis media. We found abundant evidence of recombination among LPS genes of NTHi, a finding in marked contrast to previous analyses of biosynthetic genes for capsular polysaccharide, a well-documented virulence factor of Hi. We found mosaic sequences, linkage equilibrium between loci and a lack of congruence between gene trees. These high rates were not confined to LPS genes since evidence for similar amounts of recombination was also found in eight housekeeping genes in a subset of the same 25 isolates. These findings provide a population based foundation for a better understanding of the role of NTHi LPS as a virulence factor and its potential as a candidate vaccine