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Lee B, Kharal G, Sreenan B, Lin C, Zeng R, Fox CA, Ellison P, Ryan RO, Brett PJ, AuCoin D, Zhu X. Alkaline surface treatment and time-resolved reading of mn-doped nanocrystal signal transducer for enhanced bioassay sensitivity. J Pharm Biomed Anal 2024; 238:115840. [PMID: 37956553 PMCID: PMC10841627 DOI: 10.1016/j.jpba.2023.115840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 10/26/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Recently, Mn-doped semiconductor nanocrystals (NCs) with high brightness, long lifetimes, and low-energy excitation are emerging for time-resolved luminescence biosensing/imaging. Following our previous work on Mn-doped NCs, in this work we developed poly(styrene-co-maleic anhydride) (PSMA)-encapsulated Mn-doped AgZnInS/ZnS NCs as signal transducers for immunoassay of capsular polysaccharide (CPS), a surface antigen and also a biomarker of Burkholderia pseudomallei which causes a fatal disease called melioidosis. To enhance the assay sensitivity, a surface treatment for PSMA-encapsulated NCs (NC-probes) was performed to promote the presence of carboxyl groups that help conjugate more anti-CPS antibodies to the surface of NC-probes and thus enhance bioassay signals. Meanwhile, time-resolved reading on the luminescence of NC-probes was adopted to minimize the assay background autofluorescence. Both strategies essentially enhance the assay signal-to-background ratio (or equivalently the assay sensitivity) by increasing the signal and decreasing the background, respectively. Through performing and comparing immunoassays with different NC-probes (with and without surface treatment) and different signal reading methods (time-resolved reading and non-time-resolved reading), it was proven that the immunoassay adopting surface-treated NC-probes and time-resolved reading achieved a lower limit-of-detection (LOD) than the ones adopting non-surface-treated NC-probes or non-time-resolved reading. Moreover, the achieved LOD is comparable to the LOD of immunoassay using enzyme horseradish peroxidase as a signal transducer.
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Affiliation(s)
- Bryan Lee
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA.
| | - Gita Kharal
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA
| | - Benjamin Sreenan
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA
| | - Claire Lin
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA
| | - Ruosheng Zeng
- School of Physical Science and Technology, Guangxi University, Nanning, China
| | - Colin A Fox
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Patricia Ellison
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Robert O Ryan
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, USA
| | - Paul J Brett
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, NV, USA
| | - David AuCoin
- Department of Microbiology and Immunology, University of Nevada, Reno School of Medicine, NV, USA
| | - Xiaoshan Zhu
- Department of Electrical and Biomedical Engineering, University of Nevada, Reno, NV, USA; Biomedical Engineering Program, University of Nevada, Reno, NV, USA.
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