<p>Two thirds of patients with
diabetes avoid regularly monitoring their blood glucose levels because of the
painful and invasive nature of current blood glucose detection. As an
alternative to blood sample collection, exhaled breath condensate (EBC) has emerged
as a promising non-invasive sample from which to monitor glucose levels.
However, the inconsistency in the methods used to collect EBC significantly
impacts the reliability of reported analyte concentrations in EBC. Furthermore,
this dilute sample matrix requires a highly sensitive glucose biosensor to
enable robust and accurate glucose detection at the point-of-care. Together, a
reliable collection method and sensitive detection system can enable accurate
modeling of glucose transport from blood to breath that is reflective of airway
glucose homeostasis.</p>
<p> I address
this research gap by simultaneously designing a standardized EBC collection
method that allows for separation of dead space and alveolar air and developing
a competitive fluorescent biosensor that can resolve micromolar glucose
concentrations changes. First, I develop a low-cost, automated condenser that selectively
collects exhaled breath that has been exchanged with lung fluid based on the
detection of higher breath temperatures that are characteristic of the lower
respiratory regions. Using this device, I investigate the relationship between
blood and EBC glucose in diabetic and normoglycemic human subjects. Next, I
engineer the exquisitely sensitive <i>E.
coli</i> glucose binding protein (GBP) with a chemo-enzymatic tag to
selectively conjugate it to highly photostable quantum dots (QDs). Finally, I
take advantage of the competitive binding of glucose (K<sub>D</sub>=0.35 µM)
and galactose (K<sub>D</sub>=1.4 µM) to GBP to develop a fluorescent glucose
biosensor using the GBP-QD conjugate.</p>
| Identifer | oai:union.ndltd.org:purdue.edu/oai:figshare.com:article/12735989 |
| Date | 30 July 2020 |
| Creators | Divya Tankasala (9183446) |
| Source Sets | Purdue University |
| Detected Language | English |
| Type | Text, Thesis |
| Rights | CC BY 4.0 |
| Relation | https://figshare.com/articles/thesis/Selective_exhaled_breath_condensate_collection_and_competitive_fluorescent_biosensor_for_non-invasive_glucose_detection/12735989 |
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