Craig A Aspinwall
Professor, BIO5 Institute
Professor, Biomedical Engineering
Professor, Chemistry and Biochemistry-Sci
Primary Department
(520) 621-6338
Research Interest
Craig A. Aspinwall, PhD, is an Associate Professor of Chemistry and Biochemistry at the University of Arizona. Dr. Aspinwall’s research is focused on the development of novel technology that facilitates the investigation of the molecular underpinnings of disease states. His work encompasses a broad range of scientific disciplines and allows complex biochemical problems to be studied with an increasing level of molecular detail. Dr. Aspinwall has published over 40 original research papers and maintains active collaborations with several international investigators. His research has been funded by the National Institutes of Health, the National Science Foundation, the Arizona Biomedical Research Corporation, and other organizations. He is actively involved in mentoring and education of students and young scientists.

Publications

Braun, K. L., Hapuarachchi, S., Fernandez, F. M., & Aspinwall, C. A. (2006). Fast Hadamard transform capillary electrophoresis for on-line, time-resolved chemical monitoring. Analytical Chemistry, 78(5), 1628-1635.

PMID: 16503616;Abstract:

We report a new approach for collecting and deconvoluting the data in Hadamard transform capillary electrophoresis, referred to as fast Hadamard transform capillary electrophoresis (fHTCE). Using fHTCE, total analysis times can be reduced by up to 48% per multiplexed separation compared to conventional Hadamard transform capillary electrophoresis (cHTCE) while providing comparable signal-to-noise ratio enhancements. In fHT-CE, the sample is injected following a pseudorandom pulsing sequence derived from the first row of a simplex matrix (S-matrix) in contrast to cHTCE, which utilizes a sequence of twice the length. In addition to the temporal savings provided by fHTCE, a 50% reduction in sample consumption is also realized due to the decreased number of sample injections. We have applied fHTCE to the analysis of mixtures of neurotransmitters and related compounds to yield improved signal-to-noise ratios with a total analysis time under 10 s. In addition, we demonstrate the capability of fHTCE to perform time-resolved monitoring of changes in the concentration of model neurochemical compounds. © 2006 American Chemical Society.

Berggren, P., Yang, S., Murakami, M., Efanov, A. M., Uhles, S., Köhler, M., Moede, T., Fernström, A., Appelskog, I. B., Aspinwall, C. A., Zaitsev, S. V., Larsson, O., Moitoso, L., Fecher-Trost, C., Weißgerber, P., Ludwig, A., Leibiger, B., Juntti-Berggren, L., Barker, C. J., , Gromada, J., et al. (2004). Removal of Ca2+ channel β3 subunit enhances Ca2+ oscillation frequency and insulin exocytosis. Cell, 119(2), 273-284.

PMID: 15479643;Abstract:

An oscillatory increase in pancreatic β cell cytoplasmic free Ca 2+ concentration, [Ca2+]i, is a key feature in glucose-induced insulin release. The role of the voltage-gated Ca2+ channel β3 subunit in the molecular regulation of these [Ca 2+]i oscillations has now been clarified by using β3 subunit-deficient β cells. β3 knockout mice showed a more efficient glucose homeostasis compared to wild-type mice due to increased glucose-stimulated insulin secretion. This resulted from an increased glucose-induced [Ca2+]i oscillation frequency in β cells lacking the β3 subunit, an effect accounted for by enhanced formation of inositol 1,4,5-trisphosphate (InsP3) and increased Ca2+ mobilization from intracellular stores. Hence, the β3 subunit negatively modulated InsP3-induced Ca 2+ release, which is not paralleled by any effect on the voltage-gated L type Ca2+ channel. Since the increase in insulin release was manifested only at high glucose concentrations, blocking the β3 subunit in the β cell may constitute the basis for a novel diabetes therapy.

Aspinwall, C., Mansfield, E., Ross, E. E., D'Ambruoso, G. D., Keogh, J. P., Huang, Y., & Aspinwall, C. A. (2007). Fabrication and characterization of spatially defined, multiple component, chemically functionalized domains in enclosed silica channels using cross-linked phospholipid membranes. Langmuir : the ACS journal of surfaces and colloids, 23(22).

The utilization of photopolymerized phospholipids for the preparation of spatially defined, chemically functionalized, micron-sized domains within enclosed fluidic channels was recently reported (Ross, E. E.; et al. J. Am. Chem. Soc. 2005, 127, 16756-7). Fabrication of the phospholipid patterns is achieved via self-assembly of photoreactive phospholipid membranes that are subsequently cross-linked via UV-irradiation through a photomask. In this work, we have characterized the chemical and physical stability of the self-assembled, chemically functionalized, cross-linked phospholipid patterns and extended this approach to the preparation of cross-linked phospholipid patterns with multiple chemical functionalities. Poly(bis-SorbPC) patterns were found to withstand a number of chemical and physical challenges, including drying/rehydration, solvent or surfactant rinse, and extended storage without compromising the size or morphology of the cross-linked phospholipid patterns. Nonspecific adsorption of proteins was found to be markedly reduced in the presence of UV-photopolymerized poly(bis-SorbPC) compared to bare silica capillaries. The resulting barcode-like patterns were used to prepare protein-functionalized domains via covalent attachment of fluorescent proteins and active enzymes to chemically functionalized lipid headgroups. We also demonstrate multiple component polymer lipid patterns with adjacent chemically functionalized polymer lipid regions. The unique combination of stability, biocompatibility, reduced nonspecific protein adsorption, and the availability of numerous chemically functionalized lipid headgroups suggests the utility of this approach for preparing a widely applicable platform for multicomponent, high-throughput chemical sensing and screening applications.

Qian, W., Aspinwall, C. A., Battiste, M. A., & Kennedy, R. T. (2000). Detection of secretion from single pancreatic β-cells using extracellular fluorogenic reactions and confocal fluorescence microscopy. Analytical Chemistry, 72(4), 711-717.

PMID: 10701254;Abstract:

Confocal microscopy with Zinquin, a fluorogenic Zn2+-specific indicator, was used for spatially and temporally resolved measurement of Zn2+ efflux from single pancreatic β-cells. When cells were incubated in buffer containing Zinquin, application of insulin secretagogues evoked an increase in fluorescence around the surface of the cell, indicative of detection of Zn2+ efflux from the cell. The fluorescence increases corresponded spatially and temporally with measurements of exocytosis obtained simultaneously by amperometry. When images were taken at 266-ms intervals, the detection limit for Zn2+ was ~0.5 μM. With this image frequency, it was possible to observe bursts of fluorescence which were interpreted as fluctuations of Zn2+ level due to exocytosis. The average intensity of these fluorescence bursts corresponded to a Zn2+ concentration of ~7 μM. Since insulin is co-stored with Zn2+ in secretory vesicles, it was concluded that the Zn2+ efflux corresponded to exocytosis of insulin/Zn2+-containing granules from the β-cell. Exocytosis sites identified by this technique were frequently localized to one portion of the cell, indicative of active areas of release.

Ross, E. E., Mansfield, E., Huang, Y., & Aspinwall, C. A. (2005). In situ fabrication of three-dimensional chemical patterns in fused silica separation capillaries with polymerized phospholipids. Journal of the American Chemical Society, 127(48), 16756-16757.

PMID: 16316200;Abstract:

We report a new molecular approach for in situ generation of micron scale, chemically and biochemically functionalized patterns inside three-dimensional, completely enclosed fluidic channels. The formation of chemical patterns is based upon a combination of lipid bilayer self-assembly and UV photopolymerization of photoreactive, cross-linkable phospholipids. Using this approach, we have functionalized capillaries of varying inner diameters with a range of chemistries useful for protein and peptide immobilization. Here, we demonstrate the ability to produce small molecule and protein-based chemical patterns. Copyright © 2005 American Chemical Society.