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Development of Aptamer-Actuated Two-Dimensional Photonic Crystal Hydrogel Sensors

Westbay, James (2023) Development of Aptamer-Actuated Two-Dimensional Photonic Crystal Hydrogel Sensors. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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We developed a novel DNA-functionalized 2D photonic crystal hydrogel sensing motif utilizing aptamer molecular recognition groups. Photonic crystal hydrogels consist of a photonic crystal array embedded in a stimuli-responsive hydrogel. Stimuli-responsive hydrogels undergo chemoselective volume changes. In our DNA-functionalized hydrogels, hybridized DNA forms reversible hydrogel crosslinks. One of the DNA strands contains an aptamer sequence. Aptamers are short oligonucleotides that are selected to sensitively and specifically bind a chemical target. On addition of the aptamer’s binding target, competitive aptamer-target binding breaks hydrogel crosslinks, causing the hydrogel to swell. This, in turn, increases the particle spacing of the embedded photonic crystal array, shifting photonic crystal diffraction. Thus, the concentration of the chemical target can be monitored through shifts in photonic crystal diffraction.
In this work, we utilized this novel sensing motif to fabricate a sensor that detects a small molecule, adenosine. Our sensor detects adenosine in buffer and serum solutions with < 30 μM limits of detection in under 30 min. We demonstrated the generalizability of this sensing motif by fabricating another sensor that detects a protein, human thrombin. Our thrombin sensor detects thrombin in buffer and serum solutions with < 500 nM limits of detection in under 2 h. We further examined the tunability of our DNA-functionalized photonic crystal hydrogels, and optimized steps in their fabrication and operation for sensing applications.
The novel sensors reported here are robust, require minimal training to operate, and have readouts that are easy to interpret, ideally positioning them for use in resource-limited settings. The tunable properties of our photonic crystal hydrogels enable their use beyond sensing applications, for example, as drug delivery vesicles. Importantly, we have demonstrated the generalizability of this sensing platform, suggesting that sensors for other chemical targets can be readily fabricated using the described procedures.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Westbay, Jamesjhw38@pitt.edujhw380000-0003-2023-8721
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairAsher,
Committee MemberLaaser,
Committee MemberMillstone,
Committee MemberVelankar,
Date: 6 September 2023
Date Type: Publication
Defense Date: 27 April 2023
Approval Date: 6 September 2023
Submission Date: 10 May 2023
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 176
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Sensors, Hydrogels, Photonic Crystals, Aptamers
Date Deposited: 07 Sep 2023 01:31
Last Modified: 07 Sep 2023 01:31


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