Macromolecular assembly of bioluminescent protein nanoparticles for enhanced imaging

Enya Li; Caroline K. Brennan; Aaron Ramirez; Jo A. Tucker; Nina Butkovich; Vijaykumar S. Meli; Anastasia A. Ionkina; Edward L. Nelson; Jennifer A. Prescher; Szu-Wen Wang

Materials Today Bio (Dec 2022)

Macromolecular assembly of bioluminescent protein nanoparticles for enhanced imaging

Enya Li,
Caroline K. Brennan,
Aaron Ramirez,
Jo A. Tucker,
Nina Butkovich,
Vijaykumar S. Meli,
Anastasia A. Ionkina,
Edward L. Nelson,
Jennifer A. Prescher,
Szu-Wen Wang

Affiliations

Enya Li: Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA
Caroline K. Brennan: Department of Chemistry, University of California, Irvine, CA, 92697, USA
Aaron Ramirez: Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA
Jo A. Tucker: Department of Medicine, University of California, Irvine, CA, 92697, USA
Nina Butkovich: Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA
Vijaykumar S. Meli: Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA; Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA
Anastasia A. Ionkina: Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697, USA
Edward L. Nelson: Department of Medicine, University of California, Irvine, CA, 92697, USA; Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697, USA; Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA
Jennifer A. Prescher: Department of Chemistry, University of California, Irvine, CA, 92697, USA; Department of Molecular Biology & Biochemistry, University of California, Irvine, CA, 92697, USA; Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA; Department of Pharmaceutical Sciences, University of California, Irvine, CA, 92697, USA
Szu-Wen Wang: Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA; Department of Biomedical Engineering, University of California, Irvine, CA, 92697, USA; Chao Family Comprehensive Cancer Center, University of California, Irvine, CA, 92697, USA; Corresponding author. Department of Chemical & Biomolecular Engineering, University of California, Irvine, CA, 92697, USA.

Journal volume & issue: Vol. 17
p. 100455

Abstract

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Bioluminescence imaging has advantages over fluorescence imaging, such as minimal photobleaching and autofluorescence, and greater signal-to-noise ratios in many complex environments. Although significant achievements have been made in luciferase engineering for generating bright and stable reporters, the full capability of luciferases for nanoparticle tracking has not been comprehensively examined. In biocatalysis, enhanced enzyme performance after immobilization on nanoparticles has been reported. Thus, we hypothesized that by assembling luciferases onto a nanoparticle, the resulting complex could lead to substantially improved imaging properties. Using a modular bioconjugation strategy, we attached NanoLuc (NLuc) or Akaluc bioluminescent proteins to a protein nanoparticle platform (E2), yielding nanoparticles NLuc-E2 and Akaluc-E2, both with diameters of ∼45 nm. Although no significant differences were observed between different conditions involving Akaluc and Akaluc-E2, free NLuc at pH 5.0 showed significantly lower emission values than free NLuc at pH 7.4. Interestingly, NLuc immobilization on E2 nanoparticles (NLuc-E2) emitted increased luminescence at pH 7.4, and at pH 5.0 showed over two orders of magnitude (>200-fold) higher luminescence (than free NLuc), expanding the potential for imaging detection using the nanoparticle even upon endocytic uptake. After uptake by macrophages, the resulting luminescence with NLuc-E2 nanoparticles was up to 7-fold higher than with free NLuc at 48 h. Cells incubated with NLuc-E2 could also be imaged using live bioluminescence microscopy. Finally, biodistribution of nanoparticles into lymph nodes was detected through imaging using NLuc-E2, but not with conventionally-labeled fluorescent E2. Our data demonstrate that NLuc-bound nanoparticles have advantageous properties that can be utilized in applications ranging from single-cell imaging to in vivo biodistribution.

Published in Materials Today Bio

ISSN: 2590-0064 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Medicine: Medicine (General); Science: Biology (General)
Website: https://www.journals.elsevier.com/materials-today-bio

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