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Darwish GH, Massey M, Daudet G, Alde LG, Algar WR. Tetrameric Antibody Complexes and Affinity Tag Peptides for the Selective Immobilization and Imaging of Single Quantum Dots. Bioconjug Chem 2023. [PMID: 37243625 DOI: 10.1021/acs.bioconjchem.3c00142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Colloidal semiconductor quantum dots (QDs) are of widespread interest as fluorescent labels for bioanalysis and imaging applications. Single-particle measurements have proven to be a very powerful tool for better understanding the fundamental properties and behaviors of QDs and their bioconjugates; however, a recurring challenge is the immobilization of QDs in a solution-like environment that minimizes interactions with a bulk surface. Immobilization strategies for QD-peptide conjugates are particularly underdeveloped within this context. Here, we present a novel strategy for the selective immobilization of single QD-peptide conjugates using a combination of tetrameric antibody complexes (TACs) and affinity tag peptides. A glass substrate is modified with an adsorbed layer of concanavalin A (ConA) that binds a subsequent layer of dextran that minimizes nonspecific binding. A TAC with anti-dextran and anti-affinity tag antibodies binds to the dextran-coated glass surface and to the affinity tag sequence of QD-peptide conjugates. The result is spontaneous and sequence-selective immobilization of single QDs without any chemical activation or cross-linking. Controlled immobilization of multiple colors of QDs is possible using multiple affinity tag sequences. Experiments confirmed that this approach positions the QD away from the bulk surface. The method supports real-time imaging of binding and dissociation, measurements of Förster resonance energy transfer (FRET), tracking of dye photobleaching, and detection of proteolytic activity. We anticipate that this immobilization strategy will be useful for studies of QD-associated photophysics, biomolecular interactions and processes, and digital assays.
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Affiliation(s)
- Ghinwa H Darwish
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Melissa Massey
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Gabrielle Daudet
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - Luis G Alde
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
| | - W Russ Algar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada V6T 1Z1
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Cameron TC, Randhawa A, Grist SM, Bennet T, Hua J, Alde LG, Caffrey TM, Wellington CL, Cheung KC. PDMS Organ-On-Chip Design and Fabrication: Strategies for Improving Fluidic Integration and Chip Robustness of Rapidly Prototyped Microfluidic In Vitro Models. Micromachines (Basel) 2022; 13:mi13101573. [PMID: 36295926 PMCID: PMC9609846 DOI: 10.3390/mi13101573] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 09/07/2022] [Accepted: 09/15/2022] [Indexed: 05/31/2023]
Abstract
The PDMS-based microfluidic organ-on-chip platform represents an exciting paradigm that has enjoyed a rapid rise in popularity and adoption. A particularly promising element of this platform is its amenability to rapid manufacturing strategies, which can enable quick adaptations through iterative prototyping. These strategies, however, come with challenges; fluid flow, for example, a core principle of organs-on-chip and the physiology they aim to model, necessitates robust, leak-free channels for potentially long (multi-week) culture durations. In this report, we describe microfluidic chip fabrication methods and strategies that are aimed at overcoming these difficulties; we employ a subset of these strategies to a blood-brain-barrier-on-chip, with others applied to a small-airway-on-chip. Design approaches are detailed with considerations presented for readers. Results pertaining to fabrication parameters we aimed to improve (e.g., the thickness uniformity of molded PDMS), as well as illustrative results pertaining to the establishment of cell cultures using these methods will also be presented.
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Affiliation(s)
- Tiffany C. Cameron
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Avineet Randhawa
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Samantha M. Grist
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Dream Photonics Inc., Vancouver, BC V6T 0A7, Canada
| | - Tanya Bennet
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Jessica Hua
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Luis G. Alde
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Chemistry, University of British Columbia, Vancouver, BC V6T 1Z1, Canada
| | - Tara M. Caffrey
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Cheryl L. Wellington
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 2B5, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Karen C. Cheung
- School of Biomedical Engineering, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
- Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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