Millimeter-Deep Detection of Single Shortwave-Infrared-Emitting Polymer Dots through Turbid Media
Abstract
Fluorescence imaging at longer wavelengths, especially in the shortwave-infrared (SWIR: 1000–1700 nm) region, leads to a substantial decrease in light attenuation, scattering, and background autofluorescence, thereby enabling enhanced penetration into biological tissues. The limited selection of fluorescent probes is a major bottleneck in SWIR fluorescence imaging. Here, we develop SWIR-emitting nanoparticles composed of donor–acceptor-type conjugated polymers. The bright SWIR fluorescence of the polymer dots (primarily attributable to their large absorption cross-section and high fluorescence saturation intensity (as high as 113 kW·cm –2 )) enables the unprecedented detection of single particles as small as 14 nm through millimeter-thick turbid media. Unlike most SWIR-emitting nanomaterials, which have an excited-state lifetime in the range of microseconds to milliseconds, our polymer dots exhibit a subnanosecond excited-state lifetime. These characteristics enable us to demonstrate new time-gated single-particle imaging with a high signal-to-background ratio. These findings expand the range of potential applications of single-particle deep-tissue imaging.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
Photophysical characterization demonstrated that Φfl was independent of the particle size, whereas the fluorescence brightness under microscopy conditions increased gradually with the size of Pdots.
“Photophysical characterization demonstrated that Φfl was independent of the particle size, whereas the fluorescence brightness under microscopy conditions increased gradually with the size of Pdots.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
Single-particle SWIR fluorescence imaging with one-photon excitation has recently been demonstrated using SWIR emitting Pdots consisting of PSN conjugated polymer.
“Single-particle SWIR fluorescence imaging with one-photon excitation has recently been demonstrated using SWIR emitting Pdots consisting of PSN CP (Figure 14).215”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
Using a sub-nanosecond time-gated imaging mode with a high repetition rate pulsed laser, a significant improvement in signal-to-background ratio (29× improvement of SBR) has been observed for PSN Pdots.
“Using this mode of time-gated imaging, a significant improvement in signal-to-background-ratio (29× improvement of SBR) has been observed for the PSN Pdots (Figure 16).215”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
The improvement of SBR was achieved without substantially affecting the detection efficiency of the emitted fluorescence photon.
“The improvement of SBR was achieved without substantially affecting the detection efficiency of the emitted fluorescence photon, which is the major disadvantage in afterglow fluorescence imaging, where the improved SBR is achieved at the expense of fluorescence brightness.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
The very bright SWIR fluorescence of the PSN Pdots enabled single-particle imaging through tissue phantoms that mimic optical properties of biological tissues.
“The very bright SWIR fluorescence of the PSN Pdots enabled single-particle imaging through tissue phantoms that mimic optical properties of biological tissues.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
The increase in fluorescence brightness with Pdot size was primarily attributed to their large absorption cross section and high fluorescence saturation intensity.
“This was primarily attributed to their large absorption cross section and high fluorescence saturation intensity.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
SWIR emitting Pdots (PSN and BBT) with short excited-state lifetimes (in the order of sub-nanosecond) showed higher saturation intensities.
“On the other hand, SWIR emitting Pdots (PSN and BBT) with short excited-state lifetimes (in the order of sub-nanosecond) showed higher saturation intensities (Figure 15).215”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
Detection of the Pdots through a millimeter-thick phantom was demonstrated using Pdots as small as 14 nm.
“A detection of the Pdots through a millimeter-thick phantom was demonstrated using Pdots as small as 14 nm.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
SWIR emitting inorganic nanoparticles (PbS QDs) exhibit relatively low saturation intensities due to the long excited-state lifetime (in the order of microseconds).
“On the one hand, SWIR emitting inorganic nanoparticles (PbS QDs) exhibit relatively low saturation intensities due to the long excited-state lifetime (in the order of microseconds).”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
PSN Pdots with diameters of 3.5, 14.3, and 31.9 nm were obtained by controlling the size of nanoparticles formulated in the nanoprecipitation process with an adjusted ratio of the organic to water phases.
“PSN Pdots with diameters of 3.5, 14.3, and 31.9 nm were obtained by this protocol.”
From The Pursuit of Shortwave Infrared-Emitting Nanoparticles with Bright Fluorescence through Molecular Design and Excited-State Engineering of Molecular Aggregates (2022) · cites this paper as [215]
Cites
Second window for in vivo imaging
Smith, A. M., Mancini, M. C., & Nie, S. (2009) · Nature Nanotechnology · doi:10.1038/nnano.2009.326 · Cited by 2,848 · see citing works
A small-molecule dye for NIR-II imaging
Antaris, A. L., Chen, H., Cheng, K., Sun, Y., Hong, G., Qu, C., Diao, S., Deng, Z., Hu, X., Zhang, B., et al. (2016) · Nature Materials · doi:10.1038/nmat4476 · Cited by 1,778 · see citing works
Size-Dependent Optical Properties of Colloidal PbS Quantum Dots
Moreels, I., Lambert, K., Smeets, D., Muynck, D. D., Nollet, T., Martins, J. C., Vanhaecke, F., Vantomme, A., Delerue, C., Allan, G., et al. (2009) · ACS Nano · doi:10.1021/nn900863a · Cited by 1,256 · see citing works
Through-skull fluorescence imaging of the brain in a new near-infrared window
Hong, G., Diao, S., Chang, J., Antaris, A. L., Chen, C., Zhang, B., Zhao, S., Atochin, D. N., Huang, P. L., Andreasson, K. I., et al. (2014) · Nature Photonics · doi:10.1038/nphoton.2014.166 · Cited by 1,052 · see citing works
Multifunctional in vivo vascular imaging using near-infrared II fluorescence
Hong, G., Lee, J. C., Robinson, J. T., Raaz, U., Xie, L., Huang, N. F., Cooke, J. P., & Dai, H. (2012) · Nature Medicine · doi:10.1038/nm.2995 · Cited by 995 · see citing works
Rare-earth-doped biological composites as in vivo shortwave infrared reporters
Naczynski, D. J., Tan, M. C., Zevon, M., Wall, B., Kohl, J., Kulesa, A. B., Chen, S., Roth, C. M., Riman, R. E., & Moghe, P. V. (2013) · Nature Communications · doi:10.1038/ncomms3199 · Cited by 757 · see citing works
Hemmer, E., Benayas, A., Légaré, F., & Vetrone, F. (2016) · Nanoscale Horizons · doi:10.1039/c5nh00073d · Cited by 732 · see citing works
The cytotoxicity of cadmium-based quantum dots
Chen, N., He, Y., Su, Y., Li, X., Huang, Q., Wang, H., Zhang, X., Tai, R., & Fan, C. (2011) · Biomaterials · doi:10.1016/j.biomaterials.2011.10.070 · Cited by 722 · see citing works
Carr, J. A., Franke, D., Caram, J. R., Perkinson, C. F., Saif, M., Askoxylakis, V., Datta, M., Fukumura, D., Jain, R. K., Bawendi, M. G., et al. (2018) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.1718917115 · Cited by 721 · see citing works
Next-generation in vivo optical imaging with short-wave infrared quantum dots
Bruns, O. T., Bischof, T. S., Harris, D. K., Franke, D., Shi, Y., Riedemann, L., Bartelt, A., Jaworski, F. B., Carr, J. A., Rowlands, C. J., et al. (2017) · Nature Biomedical Engineering · doi:10.1038/s41551-017-0056 · Cited by 686 · see citing works
Hong, G., Zou, Y., Antaris, A. L., Diao, S., Wu, D., Cheng, K., Zhang, X., Chen, C., Liu, B., He, Y., et al. (2014) · Nature Communications · doi:10.1038/ncomms5206 · Cited by 563 · see citing works
Sheng, Z., Guo, B., Hu, D., Xu, S., Wu, W., Liew, W. H., Yao, K., Jiang, J., Liu, C., Zheng, H., et al. (2018) · Advanced Materials · doi:10.1002/adma.201800766 · Cited by 445 · see citing works
Wilson, R. H., Nadeau, K. P., Jaworski, F. B., Tromberg, B. J., & Durkin, A. J. (2015) · Journal of Biomedical Optics · doi:10.1117/1.jbo.20.3.030901 · Cited by 415 · see citing works
Flavylium Polymethine Fluorophores for Near‐ and Shortwave Infrared Imaging
Cosco, E. D., Caram, J. R., Bruns, O. T., Franke, D., Day, R. A., Farr, E. P., Bawendi, M. G., & Sletten, E. M. (2017) · Angewandte Chemie International Edition · doi:10.1002/anie.201706974 · Cited by 415 · see citing works
Traumatic Brain Injury Imaging in the Second Near‐Infrared Window with a Molecular Fluorophore
Zhang, X., Wang, H., Antaris, A. L., Li, L., Diao, S., Ma, R., Nguyen, A., Hong, G., Ma, Z., Wang, J., et al. (2016) · Advanced Materials · doi:10.1002/adma.201600706 · Cited by 386 · see citing works
Design of Highly Emissive Polymer Dot Bioconjugates for In Vivo Tumor Targeting
Wu, C., Hansen, S. J., Hou, Q., Yu, J., Zeigler, M. B., Jin, Y., Burnham, D. R., McNeill, J., Olson, J. M., & Chiu, D. T. (2011) · Angewandte Chemie International Edition · doi:10.1002/anie.201007461 · Cited by 362 · see citing works
Carbon nanotubes: Evaluation of toxicity at biointerfaces
Mohanta, D., Patnaik, S., Sood, S., & Das, N. (2019) · Journal of Pharmaceutical Analysis · doi:10.1016/j.jpha.2019.04.003 · Cited by 297 · see citing works
Su, Y., Hu, M. Y., Fan, C., He, Y., Li, Q., Li, W., Wang, L., Shen, P., & Huang, Q. (2010) · Biomaterials · doi:10.1016/j.biomaterials.2010.02.074 · Cited by 277 · see citing works
Self-citationGodin, A. G., Varela, J. A., Gao, Z., Danné, N., Dupuis, J. P., Lounis, B., Groc, L., & Cognet, L. (2017) · Nature Nanotechnology · doi:10.1038/nnano.2016.248 · Cited by 253 · see citing works
High-sensitivity imaging of time-domain near-infrared light transducer
Gu, Y., Guo, Z., Yuan, W., Kong, M., Liu, Y., Liu, Y., Gao, Y., Feng, W., Wang, F., Zhou, J., et al. (2019) · Nature Photonics · doi:10.1038/s41566-019-0437-z · Cited by 249 · see citing works
Guo, B., Feng, Z., Hu, D., Xu, S., Middha, E., Pan, Y., Liu, C., Zheng, H., Qian, J., Sheng, Z., et al. (2019) · Advanced Materials · doi:10.1002/adma.201902504 · Cited by 227 · see citing works
Shortwave‐infrared (SWIR) emitters for biological imaging: a review of challenges and opportunities
Thimsen, E., Sadtler, B., & Berezin, M. Y. (2017) · Nanophotonics · doi:10.1515/nanoph-2017-0039 · Cited by 207 · see citing works
Shortwave Infrared Imaging with J-Aggregates Stabilized in Hollow Mesoporous Silica Nanoparticles
Chen, W., Cheng, C.-A., Cosco, E. D., Ramakrishnan, S., Lingg, J. G. P., Bruns, O. T., Zink, J. I., & Sletten, E. M. (2019) · Journal of the American Chemical Society · doi:10.1021/jacs.9b05195 · Cited by 202 · see citing works
Low Optical Bandgap Polythiophenes by an Alternating Donor/Acceptor Repeat Unit Strategy
Zhang, Q. T., & Tour, J. M. (1997) · Journal of the American Chemical Society · doi:10.1021/ja9640399 · Cited by 190 · see citing works
Single-molecule techniques in biophysics: a review of the progress in methods and applications
Miller, H., Zhou, Z., Shepherd, J. W., Wollman, A. J. M., & Leake, M. C. (2017) · Reports on Progress in Physics · doi:10.1088/1361-6633/aa8a02 · Cited by 184 · see citing works
Molecular Imaging in the Second Near‐Infrared Window
Wan, H., Du, H., Wang, F., & Dai, H. (2019) · Advanced Functional Materials · doi:10.1002/adfm.201900566 · Cited by 180 · see citing works
Er:Yb:NaY 2 F 5 O up-converting nanoparticles for sub-tissue fluorescence lifetime thermal sensing
Savchuk, O. A., Haro‐González, P., Carvajal, J. J., Jaque, D., Massons, J., Aguiló, M., & Dı́az, F. (2014) · Nanoscale · doi:10.1039/c4nr02305f · Cited by 158 · see citing works
Organic dyes for deep bioimaging
Schnermann, M. J. (2017) · Nature · doi:10.1038/nature24755 · Cited by 157 · see citing works
Wu, I.-C., Yu, J., Ye, F., Rong, Y., Gallina, M. E., Fujimoto, B. S., Zhang, Y., Chan, Y.-H., Sun, W., Zhou, X.-H., et al. (2015) · Journal of the American Chemical Society · doi:10.1021/ja5123045 · Cited by 148 · see citing works
Polymer Nanoparticles for Nanomedicines
Ponchel, G., & Vauthier, C. (2016) · Springer eBooks · doi:10.1007/978-3-319-41421-8 · Cited by 128 · see citing works
Size effects of single-walled carbon nanotubes onin vivoandin vitropulmonary toxicity
Fujita, K., Fukuda, M., Endoh, S., Maru, J., Kato, H., Nakamura, A., Shinohara, N., Uchino, K., & Honda, K. (2015) · Inhalation Toxicology · doi:10.3109/08958378.2015.1026620 · Cited by 95 · see citing works
Multilayer silicone phantoms for the evaluation of quantitative optical techniques in skin imaging
Saager, R. B., Kondru, C., Au, K., Sry, K., Ayers, F. R., & Durkin, A. J. (2010) · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · doi:10.1117/12.842249 · Cited by 92 · see citing works
Khalin, I., Heimburger, D., Melnychuk, N., Collot, M., Groschup, B., Hellal, F., Reisch, A., Plesnila, N., & Klymchenko, A. S. (2020) · ACS Nano · doi:10.1021/acsnano.0c01505 · Cited by 82 · see citing works
Piwoński, H., Michinobu, T., & Habuchi, S. (2017) · Nature Communications · doi:10.1038/ncomms15256 · Cited by 65 · see citing works
Self-citationGreening, G. J., Istfan, R., Higgins, L. M., Balachandran, K., Roblyer, D. M., Pierce, M. C., & Muldoon, T. J. (2014) · Journal of Biomedical Optics · doi:10.1117/1.jbo.19.11.115002 · Cited by 54 · see citing works
Wu, J., Lee, H. J., You, L., Luo, X., Hasegawa, T., Huang, K., Lin, P., Ratliff, T. L., Ashizawa, M., Mei, J., et al. (2020) · Small · doi:10.1002/smll.202001215 · Cited by 47 · see citing works
Fluorescence saturation in confocal microscopy
Visscher, K. M., Brakenhoff, G. J., & Visser, T. D. (1994) · Journal of Microscopy · doi:10.1111/j.1365-2818.1994.tb03479.x · Cited by 44 · see citing works
Toxicity and oxidative stress induced by semiconducting polymer dots in RAW264.7 mouse macrophages
Ye, F., White, C. C., Jin, Y., Hu, X., Hayden, S., Zhang, X., Gao, X., Kavanagh, T. J., & Chiu, D. T. (2015) · Nanoscale · doi:10.1039/c5nr01857a · Cited by 40 · see citing works
Piwoński, H., Li, W., Wang, Y., Michinobu, T., & Habuchi, S. (2020) · ACS Applied Polymer Materials · doi:10.1021/acsapm.9b00967 · Cited by 36 · see citing works
Self-citationByrd, B. K., Marois, M., Tichauer, K. M., Wirth, D. J., Hong, J., Leonor, J. P., Elliott, J. T., Paulsen, K. D., & Davis, S. C. (2019) · Journal of Biomedical Optics · doi:10.1117/1.jbo.24.8.080501 · Cited by 21 · see citing works
Flagged first, then by citations
Cited by
Sorted by citations
Yin, C., Tai, X., Li, X., Tan, J., Lee, C., Sun, P., Fan, Q., & Huang, W. (2021) · Chemical Engineering Journal · doi:10.1016/j.cej.2021.132098 · Cited by 82 · see citing works
Saleh, M., Gul, A., Nasır, A., Moses, T. O., Nural, Y., & Yabalak, E. (2024) · Journal of Industrial and Engineering Chemistry · doi:10.1016/j.jiec.2024.11.052 · Cited by 69 · see citing works
Highly Efficient Luminescence from Charge-Transfer Gold Nanoclusters Enabled by Lewis Acid
Huang, K., Xiu, L.-F., Fang, X., Yang, M., Noreldeen, H. A. A., Chen, W., & Deng, H. (2022) · The Journal of Physical Chemistry Letters · doi:10.1021/acs.jpclett.2c02724 · Cited by 47 · see citing works
Piwoński, H., Nozue, S., Fujita, H., Michinobu, T., & Habuchi, S. (2021) · Nano Letters · doi:10.1021/acs.nanolett.0c04928 · Cited by 45 · see citing works
Self-citationPiwoński, H., Nozue, S., & Habuchi, S. (2022) · ACS Nanoscience Au · doi:10.1021/acsnanoscienceau.1c00038 · Cited by 39 · see citing works
Self-citationHu, X., Jia, Q., Fang, Q., Song, C., Zhang, R., Liang, Y., Yang, Z., Wu, J., Li, H., Zhao, T., et al. (2024) · Advanced Functional Materials · doi:10.1002/adfm.202407100 · Cited by 38 · see citing works
Haye, L., Diriwari, P. I., Alhalabi, A., Gallavardin, T., Combes, A., Klymchenko, A. S., Hildebrandt, N., Guével, X. L., & Reisch, A. (2022) · Advanced Optical Materials · doi:10.1002/adom.202201474 · Cited by 35 · see citing works
Terayama, K., Habuchi, S., & Michinobu, T. (2023) · Journal of Polymer Science · doi:10.1002/pol.20230421 · Cited by 14 · see citing works
Self-citationJia, H., Xu, N., Nagai, Y., Doi, M., Sawada, T., Serizawa, T., Ando, S., Habuchi, S., & Michinobu, T. (2023) · Polymer Chemistry · doi:10.1039/d3py00168g · Cited by 11 · see citing works
Self-citationLu, J., Zeng, Y., Chang, X., Hong, Y., & Hu, X. (2021) · Applied Physics Express · doi:10.35848/1882-0786/abe601 · Cited by 10 · see citing works
He, W., Washino, Y., Murata, K., Nozaki, N., Matsumoto, H., & Michinobu, T. (2022) · Materials Chemistry and Physics · doi:10.1016/j.matchemphys.2022.125861 · Cited by 9 · see citing works
Self-citationBallistic imaging through an intense scattering medium using a subtractive optical Kerr gate
Zheng, Y., Zhu, C., Zhao, F., Tan, W., Chen, R., Guo, K., Zhang, J., Han, D., Ren, K., Lv, G., et al. (2021) · Infrared Physics & Technology · doi:10.1016/j.infrared.2021.103767 · Cited by 8 · see citing works
Single-Particle Optical Imaging for Ultrasensitive Bioanalysis
Liu, Y., Li, B., Liu, B., & Zhang, K. (2022) · Biosensors · doi:10.3390/bios12121105 · Cited by 7 · see citing works
Chen, Z., Wu, Z., Chen, Y., Zhang, S., Jiang, Z., Li, W., Zhao, Y. F., Wang, Y., & Liu, Y. (2023) · Materials Chemistry Frontiers · doi:10.1039/d3qm01189e · Cited by 7 · see citing works
Self-citationKüçükdeğer, E., Zhang, Y., Zhang, J., Liu, Y., Jia, X., & Johnson, B. N. (2023) · IEEE Transactions on Automation Science and Engineering · doi:10.1109/tase.2023.3279338 · Cited by 4 · see citing works
Niyom, Y., Madirov, E., Bhiri, N. M., Chauhan, A., Richards, B. S., Flood, A. E., Crespy, D., & Turshatov, A. A. (2023) · Optical Materials · doi:10.1016/j.optmat.2023.113833 · Cited by 3 · see citing works
Piwoński, H., Szczepski, K., Jaremko, M., Jaremko, Ł., & Habuchi, S. (2024) · ACS Omega · doi:10.1021/acsomega.4c00240 · Cited by 3 · see citing works
Self-citationDas, N. K., Piwoński, H., Nozue, S., Joshi, M., Terayama, K., Michinobu, T., & Habuchi, S. (2025) · ACS Applied Materials & Interfaces · doi:10.1021/acsami.5c17687
Self-citationLiu, C., Xie, L., Gu, X., Li, L., Chen, M., & Zheng, Q. (2026) · Advanced Functional Materials · doi:10.1002/adfm.78564
- Authors
- Piwoński, H., Wang, Y., Li, W., Michinobu, T., & Habuchi, S.
- Affiliations
- King Abdullah University of Science and Technology (SA)
- Tokyo Institute of Technology (JP)
- Corresponding author
- Piwoński, Hubert
- Habuchi, Satoshi
- Venue
- Nano Letters
- Publisher
- American Chemical Society (ACS)
- Published
- 2020-11-18
- Volume
- 20
- Issue
- 12
- Pages
- 8803-8810
- ISSN
- 1530-6984 (ISSN-L)
- 1530-6992
- OpenAlex
- W3102344778
- Cited by
- 19
- References
- 40
- Citations by year
- 2026: 1 · 2025: 1 · 2024: 3 · 2023: 5 · 2022: 5 · 2021: 4
- FWCI
- 1.36
- Type
- journal article
- Language
- en
- Open access
- closed
- Licence
- Locations
- Nano Letters (publishedVersion)
- PubMed (publishedVersion)
- Institutional Repositories DataBase (IRDB) (submittedVersion)
- King Abdullah University of Science and Technology Repository (King Abdullah University of Science and Technology) (submittedVersion)
- Tokyo Tech Research Repository (Tokyo Institute of Technology) (submittedVersion)
- Funders
- King Abdullah University of Science and Technology (OSR-2016-2967-CRG5)
- Topics
- Physical Sciences › Materials Science › Materials Chemistry › Luminescence and Fluorescent Materials
- Physical Sciences › Materials Science › Materials Chemistry › Quantum Dots Synthesis And Properties
- Physical Sciences › Materials Science › Materials Chemistry › Luminescence Properties of Advanced Materials
- Keywords
- polymer dots, donor-acceptor polymers, single-particle detection, turbid media, deep tissue imaging, time-gated imaging, fluorescence saturation, autofluorescence suppression, light scattering
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
