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Darwish GH, Baker DV, Algar WR. Supra-Quantum Dot Assemblies to Maximize Color-Based Multiplexed Fluorescence Detection with a Smartphone Camera. ACS Sens 2023; 8:4686-4695. [PMID: 37983019 DOI: 10.1021/acssensors.3c01741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
Photoluminescence (PL) imaging and bioanalysis with smartphone-based devices are of growing interest for point-of-care/point-of-need diagnostics. Strategies for maximizing sensitivity have been explored in this context, but color multiplexing has been very limited, with its maximum level unexplored. Here, we evaluated color multiplexing with smartphone-based PL imaging by using supra-nanoparticle assemblies of quantum dots (supra-QDs). These materials were prepared as composite colors that were tailored to the red-green-blue (RGB) color space of smartphone cameras by coassembling different ratios of R-, G-, and B-emitting QDs on a silica nanoparticle scaffold. The supra-QDs were characterized and used to label cell-sized objects that were measured under flow with a smartphone-based device. Each color followed an approximately linear trajectory in the RGB space, and training of support vector machine models enabled color classification with overall accuracies ≥87% for 10-color multiplexing and better accuracies for fewer colors. Most misclassification occurred at low signal levels, such that establishing a nonclassifiable zone near the origin of RGB color space improved the overall 10-color classification accuracy to ≥94%. Similar improvements in accuracy with greater retention of data were possible with a probabilistic rather than a radial threshold. Simulations that were parameterized by experimental data suggested that ≥14-color multiplexing with accuracies ≥90% should be possible with an optimized supra-QD color set. This study is an important foundation for advancing RGB color-based multiplexing for imaging and analyses with smartphone cameras and related charge-coupled device and CMOS color image sensor technologies.
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Affiliation(s)
- Ghinwa H Darwish
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, British Columbia, Canada
| | - Daina V Baker
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, British Columbia, Canada
| | - W Russ Algar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver V6T 1Z1, British Columbia, Canada
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Kanani SS, Tsai HY, Algar WR. Quantitative and Multiplexed Chopper-Based Time-Gated Imaging for Bioanalysis on a Smartphone. Anal Chem 2023; 95:13258-13265. [PMID: 37611229 DOI: 10.1021/acs.analchem.3c02397] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
Smartphones are emerging platforms for point-of-care diagnostics (POCDs), where the on-board camera is, for example, used to image fluorescence. Many laboratory instruments are capable of time-gated (TG) photoluminescence (PL) measurements─an analytical method leveraged by multiple commercial assay kits. When paired with long-lived PL emitters such as luminescent lanthanide complexes (LLCs), time-gating eliminates background from sample autofluorescence and many other sources. This capability is amenable to minimally processed samples and would thus be useful for POCDs on a smartphone-based platform. Here, we report a double-chopper design for TG PL imaging using a portable, 3D-printed, smartphone-based device. The rotation speed, dimensions, and overlap of the chopper blades and gaps set the timing parameters, with delay times on the order of hundreds of microseconds to milliseconds. The device was capable of quantitative TG imaging of PL from terbium(III) and europium(III) LLCs, including rejection of short-lived PL background from serum and tissue phantoms, spectral and temporal multiplexing, a model time-gated Förster resonance energy transfer (TG-FRET) assay, and imaging of cells. As the first smartphone-based demonstrations of these important analytical capabilities, this work is an important foundation for developing POCD methods based on TG PL imaging.
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Affiliation(s)
- Sahil S Kanani
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Hsin-Yun Tsai
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - W Russ Algar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
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Marcos-Fernández R, Sánchez B, Ruiz L, Margolles A. Convergence of flow cytometry and bacteriology. Current and future applications: a focus on food and clinical microbiology. Crit Rev Microbiol 2023; 49:556-577. [PMID: 35749433 DOI: 10.1080/1040841x.2022.2086035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 05/12/2022] [Accepted: 05/31/2022] [Indexed: 11/03/2022]
Abstract
Since its development in the 1960s, flow cytometry (FCM) was quickly revealed a powerful tool to analyse cell populations in medical studies, yet, for many years, was almost exclusively used to analyse eukaryotic cells. Instrument and methodological limitations to distinguish genuine bacterial signals from the background, among other limitations, have hampered FCM applications in bacteriology. In recent years, thanks to the continuous development of FCM instruments and methods with a higher discriminatory capacity to detect low-size particles, FCM has emerged as an appealing technique to advance the study of microbes, with important applications in research, clinical and industrial settings. The capacity to rapidly enumerate and classify individual bacterial cells based on viability facilitates the monitoring of bacterial presence in foodstuffs or clinical samples, reducing the time needed to detect contamination or infectious processes. Besides, FCM has stood out as a valuable tool to advance the study of complex microbial communities, or microbiomes, that are very relevant in the context of human health, as well as to understand the interaction of bacterial and host cells. This review highlights current developments in, and future applications of, FCM in bacteriology, with a focus on those related to food and clinical microbiology.
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Affiliation(s)
- Raquel Marcos-Fernández
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Borja Sánchez
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Lorena Ruiz
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
| | - Abelardo Margolles
- Department of Microbiology and Biochemistry of Dairy Products, Dairy Research Institute of Asturias, Spanish National Research Council (IPLA-CSIC), Asturias, Spain
- Functionality and Ecology of Beneficial Microbes (MicroHealth) Group, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Asturias, Spain
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Nath P, Mahtaba KR, Ray A. Fluorescence-Based Portable Assays for Detection of Biological and Chemical Analytes. SENSORS (BASEL, SWITZERLAND) 2023; 23:s23115053. [PMID: 37299780 DOI: 10.3390/s23115053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/16/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023]
Abstract
Fluorescence-based detection techniques are part of an ever-expanding field and are widely used in biomedical and environmental research as a biosensing tool. These techniques have high sensitivity, selectivity, and a short response time, making them a valuable tool for developing bio-chemical assays. The endpoint of these assays is defined by changes in fluorescence signal, in terms of its intensity, lifetime, and/or shift in spectrum, which is monitored using readout devices such as microscopes, fluorometers, and cytometers. However, these devices are often bulky, expensive, and require supervision to operate, which makes them inaccessible in resource-limited settings. To address these issues, significant effort has been directed towards integrating fluorescence-based assays into miniature platforms based on papers, hydrogels, and microfluidic devices, and to couple these assays with portable readout devices like smartphones and wearable optical sensors, thereby enabling point-of-care detection of bio-chemical analytes. This review highlights some of the recently developed portable fluorescence-based assays by discussing the design of fluorescent sensor molecules, their sensing strategy, and the fabrication of point-of-care devices.
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Affiliation(s)
- Peuli Nath
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
| | - Kazi Ridita Mahtaba
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
| | - Aniruddha Ray
- Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606, USA
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Rees K, Darwish GH, Algar WR. Dextran-Functionalized Super-nanoparticle Assemblies of Quantum Dots for Enhanced Cellular Immunolabeling and Imaging. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18672-18684. [PMID: 37018127 DOI: 10.1021/acsami.3c00861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Colloidal semiconductor quantum dots (QDs) are a popular material for applications in bioanalysis and imaging. Although individual QDs are bright, some applications benefit from the use of even brighter materials. One approach to achieve higher brightness is to form super-nanoparticle (super-NP) assemblies of many QDs. Here, we present the preparation, characterization, and utility of dextran-functionalized super-NP assemblies of QDs. Amphiphilic dextran was synthesized and used to encapsulate many hydrophobic QDs via a simple emulsion-based method. The resulting super-NP assemblies or "super-QDs" had hydrodynamic diameters of ca. 90-160 nm, were characterized at the ensemble and single-particle levels, had orders-of-magnitude superior brightness compared to individual QDs, and were non-blinking. Additionally, binary mixtures of red, green, and blue (RGB) colors of QDs were used to prepare super-QDs, including colors difficult to obtain from individual QDs (e.g., magenta). Tetrameric antibody complexes (TACs) enabled simple antibody conjugation for selective cellular immunolabeling and imaging with both an epifluorescence microscope and a smartphone-based platform. The technical limitations of the latter platform were overcome by the increased per-particle brightness of the super-QDs, and the super-QDs outperformed individual QDs in both cases. Overall, the super-QDs are a very promising material for bioanalysis and imaging applications where brightness is paramount.
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Affiliation(s)
- Kelly Rees
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - Ghinwa H Darwish
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
| | - W Russ Algar
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC, V6T 1Z1, Canada
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Mayder DM, Christopherson CJ, Primrose WL, Lin ASM, Hudson ZM. Polymer dots and glassy organic dots using dibenzodipyridophenazine dyes as water-dispersible TADF probes for cellular imaging. J Mater Chem B 2022; 10:6496-6506. [PMID: 35979840 DOI: 10.1039/d2tb01252a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Fluorescence imaging of living cells is key to better understanding cellular morphology and biological processes. Water-dispersible nanoparticles exhibiting thermally activated delayed fluorescence (TADF) have recently emerged as useful probes for time-resolved fluorescence imaging (TRFI), circumventing interference from biological autofluorescence. Many existing approaches, however, require TADF dyes with specific structural features, precluding many high-performance TADF materials from being used in this application. Here, we describe the synthesis of two TADF emitters based on the rigid and strongly electron-withdrawing dibenzo[a,c]dipyrido[3,2-h:2'-3'-j]phenazine-12-yl (BPPZ) motif, and demonstrate two parallel approaches for the encapsulation of these fluorophores to yield water-dispersible nanoparticles suitable for TRFI. First, fluorescent polymer dots (Pdots) were formed by dye encapsulation within cell-penetrating amphiphilic copolymers. Glassy organic nanoparticles (g-Odots) were also prepared, giving nanoparticles with higher photoluminescence quantum yields and improved colour purity. Both approaches yielded nanoparticles suitable for imaging, with reasonable uptake and cytotoxicity on the timescale of standard imaging experiments using human cervical (HeLa) and liver (HepG2) cancer cell lines. This work demonstrates two flexible strategies for preparing water-dispersible TADF nanoparticles for TRFI, both of which should be readily adaptable to nearly any existing hydrophobic TADF dye.
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Affiliation(s)
- Don M Mayder
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
| | - Cheyenne J Christopherson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
| | - William L Primrose
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
| | - Angela S-M Lin
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
| | - Zachary M Hudson
- Department of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, V6T 1Z1, Canada.
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