LED Excitation and Photomultiplier Tube Biasing and Gating Circuitry for Fluorescence Instrumentation

Persistent Link:
http://hdl.handle.net/10150/556849
Title:
LED Excitation and Photomultiplier Tube Biasing and Gating Circuitry for Fluorescence Instrumentation
Author:
Fairbanks, Jerrie Vincent
Issue Date:
2015
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Embargo:
Release after 1-Nov-2015
Abstract:
Fluorescence technologies have only begun exploiting the transient recording of lifetime-based signals and images for low nanosecond lifetimes, but the method has tremendous potential for scientific and medical applications. Low nanosecond lifetime recording in real-time can enable the tracking of metabolite concentrations in cells and tissues (e.g. cancerous tissues) without introducing foreign substances. It will also enable the tracking of reactive species (e.g. ozone) and intermediate/short-lived states in chemical reactions in the atmosphere. Current techniques all employ laser excitation, but LEDs can also be used which cause considerably less damage to live tissue. We have developed a high speed fluorescence prototype using high intensity LED pulses and novel PMT gating technology. Precision timing circuitry generates tunable width pulse signals which are driven through the LED using a comparator-based push-pull architecture. The timing circuitry also generates PMT gating pulses which are applied to the dynode chain via high voltage operational amplifiers. LED pulses with fall times (99%) as short as 2ns and PMT gating times (10% to 90%) of 3.6ns have been achieved. The prototype has been used to successfully measure the fluorescent lifetimes of Alexa Fluor 610X dye (1.7ns and 4.7ns) and riboflavin (4.5ns). Lifetimes of acridine orange were measured as follows: alone (2ns), in solution with ssDNA (3.7ns), in solution with dsDNA (5.8ns), and in solution with dsRNA (5.9ns). Finally, dsRNA was heated and allowed to cool revealing lifetimes that started at 3.7ns when hot and increased to nearly 5ns when cool.
Type:
text; Electronic Dissertation
Keywords:
Instrumentation; LED; Photomultiplier; Spectroscopy; Time-resolved; Electrical & Computer Engineering; Fluorescence
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Electrical & Computer Engineering
Degree Grantor:
University of Arizona
Advisor:
Powers, Linda S.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen
dc.titleLED Excitation and Photomultiplier Tube Biasing and Gating Circuitry for Fluorescence Instrumentationen_US
dc.creatorFairbanks, Jerrie Vincenten
dc.contributor.authorFairbanks, Jerrie Vincenten
dc.date.issued2015en
dc.publisherThe University of Arizona.en
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en
dc.description.releaseRelease after 1-Nov-2015en
dc.description.abstractFluorescence technologies have only begun exploiting the transient recording of lifetime-based signals and images for low nanosecond lifetimes, but the method has tremendous potential for scientific and medical applications. Low nanosecond lifetime recording in real-time can enable the tracking of metabolite concentrations in cells and tissues (e.g. cancerous tissues) without introducing foreign substances. It will also enable the tracking of reactive species (e.g. ozone) and intermediate/short-lived states in chemical reactions in the atmosphere. Current techniques all employ laser excitation, but LEDs can also be used which cause considerably less damage to live tissue. We have developed a high speed fluorescence prototype using high intensity LED pulses and novel PMT gating technology. Precision timing circuitry generates tunable width pulse signals which are driven through the LED using a comparator-based push-pull architecture. The timing circuitry also generates PMT gating pulses which are applied to the dynode chain via high voltage operational amplifiers. LED pulses with fall times (99%) as short as 2ns and PMT gating times (10% to 90%) of 3.6ns have been achieved. The prototype has been used to successfully measure the fluorescent lifetimes of Alexa Fluor 610X dye (1.7ns and 4.7ns) and riboflavin (4.5ns). Lifetimes of acridine orange were measured as follows: alone (2ns), in solution with ssDNA (3.7ns), in solution with dsDNA (5.8ns), and in solution with dsRNA (5.9ns). Finally, dsRNA was heated and allowed to cool revealing lifetimes that started at 3.7ns when hot and increased to nearly 5ns when cool.en
dc.typetexten
dc.typeElectronic Dissertationen
dc.subjectInstrumentationen
dc.subjectLEDen
dc.subjectPhotomultiplieren
dc.subjectSpectroscopyen
dc.subjectTime-resolveden
dc.subjectElectrical & Computer Engineeringen
dc.subjectFluorescenceen
thesis.degree.namePh.D.en
thesis.degree.leveldoctoralen
thesis.degree.disciplineGraduate Collegeen
thesis.degree.disciplineElectrical & Computer Engineeringen
thesis.degree.grantorUniversity of Arizonaen
dc.contributor.advisorPowers, Linda S.en
dc.contributor.committeememberTharp, Hal S.en
dc.contributor.committeememberWang, Janeten
dc.contributor.committeememberPowers, Linda S.en
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