Ms. Allison A. Wilhelm Profile

Allison A. Wilhelm

Graduate Assistant

SPIE Involvement:

Author

Publications (3)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 7 February 2008 Paper

Integrated capture and spectroscopic detection of viruses in an aqueous environment

Allison Wilhelm, Pierre Lucas, Kelly Reynolds, Mark Riley

Proceedings Volume 6852, 68520K (2008) https://doi.org/10.1117/12.774540

KEYWORDS: Germanium, Crystals, Proteins, Molecules, Viruses, Infrared radiation, Environmental sensing, Spectroscopy, Molecular biology, Attenuated total reflectance

Read Abstract +

A new approach to virus detection in an aqueous environment has been developed using the electrophoretic deposition of protein and viruses on a charged surface for in situ infrared characterization and identification. In this study, a potential was applied across a germanium ATR crystal, which acted as the anode, and an indium tin oxide (ITO) plate, which acted as the cathode in the electrodeposition setup. Sample aqueous solutions were placed between the germanium and the ITO with different concentrations of the protein bovine serum albumin (BSA) and the virus MS2, in tap water. The pH of the tap water was above the isoelectric point of the virus and the protein, resulting in a net negative charge for both. The negatively charged protein and virus were then driven to the surface of the positively charged germanium ATR crystal, once a potential was applied to the system. FTIR/ATR was used before and throughout electrodeposition to enable the in situ observation of the deposition with time. In this study, we evaluate the capture efficiency, compared to control experiments with no applied voltage, and the feasibility of using this approach for the collection and quantification of proteins and viruses from water samples. This technique resulted in the successful deposition of BSA, and MS2 with an applied voltage of only 1.1V. Furthermore, based on the analysis of the ATR spectra, distinct spectral features were identified for the protein and virus showing the potential for identification and characterization of biological molecules in an aqueous environment.

Proceedings Article | 15 February 2007 Paper

New tellurium based glasses for use in bio-sensing applications

Allison Wilhelm, Catherine Boussard-Pledel, Pierre Lucas, Mark Riley, Bruno Bureau, Jacques Lucas

Proceedings Volume 6433, 64330U (2007) https://doi.org/10.1117/12.724269

KEYWORDS: Glasses, Tellurium, Germanium, Iodine, Temperature metrology, Biosensing, Selenium, Silica, Chalcogenide glass, Transparency

Read Abstract +

A new family of Tellurium based glasses from the Ge-Te-I ternary system has been investigated for use in bio-sensing applications. A systematic series of compositions have been synthesized in order to explore the ternary phase diagram in an attempt to optimize the glass composition for the fiber drawing process. The characteristic temperatures Tg, the glass transition temperature, and T_x, the onset crystallization temperature, were measured in order to obtain &Dgr;T, the difference between T_g and T_x, which must be maximized for optimum fiber drawing ability. The resulting glass transition temperature range lies between 139^oC and 174^oC, with &Dgr;T values between 64^oC and 124^oC. The mechanical properties of a selected number of glass compositions were also investigated, including hardness and Young's Modulus. The Ge-Te-I glasses have an effective transmission window between 2-27 microns, encompassing the region of interest for the identification of biologically relevant species such as carbon dioxide. Furthermore, the fibering potential of the Ge-Te-I glasses makes them an interesting candidate for use in fiber evanescent wave spectroscopy (FEWS) and other bio-sensing applications.

Proceedings Article | 15 February 2006 Paper

Cell-based bio-optical sensors using chalcogenide fibers

Pierre Lucas, Allison Wilhelm, Mark Riley, Dianna DeRosa, Jayne Collier

Proceedings Volume 6083, 60830W (2006) https://doi.org/10.1117/12.654510

KEYWORDS: Optical fibers, Arsenic, Oxides, Toxicity, Glasses, Chalcogenides, Sensors, Etching, Lung, Surface roughness

Read Abstract +

An optical bio-sensor is built based on an infrared chalcogenide fiber coated with live cells. The fiber is immersed in an aqueous media appropriate for cell viability. The response of the cells to small quantities of toxicant can be monitored spectroscopically. The properties of chalcogenide fibers used for cell-based biosensors are investigated. The chemical stability of Te-As-Se fibers in aqueous media is shown to depend on the previous storage time of the fiber. Older fibers are shown to generate an oxide layer during extended exposure to air. This layer readily dissolves in aqueous solution and causes the release of As in the cell environment. The release of As during dissolution of the oxide layer is measured with ICP-MS and is shown to be complete after a couple hours. Fresh fibers do not show any detectable oxide layer and show excellent stability in aqueous solution. The surface roughness of old and fresh fibers is investigated with AFM before and after dissolution in aqueous media. Old fibers immersed in solution show sizable roughness due to the oxide surface layer dissolution. Fresh fibers do not show any detectable changes even after extended immersion in aqueous solution. The toxicity of As to various types of vertebrate cells is quantified using a colorimetric assay. Old fibers are shown to be notably toxic due to As released during dissolution. The fiber toxicity is shown to decrease when the fibers are previously washed in solution. The toxicity of the resulting wash water is then shown to increase due to the increase in As concentration.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years