{
  "abstract": "Fluorescent dye-loaded nanoparticles (NPs) offer powerful platforms for bioimaging, biosensing, and flow cytometry, but their performance is often compromised by aggregation-caused quenching and exciton trapping. Although molecular isolation can suppress aggregation, controlling exciton transport within fluorescent NPs remains challenging. Here, we demonstrate that the capping agent provides a powerful means to regulate exciton dynamics in small-molecule ionic isolation lattice (SMILES) NPs. Replacing the conventional phospholipid capping agent DSPE-PEG with poly(styrene-co-maleic anhydride) (PSMA) increases the fluorescence quantum yield more than threefold, reaching 61%. Polarization-resolved femtosecond transient absorption spectroscopy reveals markedly slower exciton depolarization with PSMA, with the anisotropy remaining at ~0.1 at long delay times, indicating restricted exciton migration and reduced trapping at nonradiative defects. This exciton confinement enhances fluorescence efficiency and substantially increases NP brightness. The capping-agent-dependent regulation of exciton transport is applicable to structurally diverse fluorophores, enabling SMILES NPs with distinct emission colors spanning the visible to near-infrared spectral range. Following antibody functionalization, these ultrabright NPs produce fluorescence signals up to 17-fold higher than commercial phycoerythrin-conjugated antibodies in flow cytometry of human peripheral blood. These findings establish capping-agent regulation of exciton transport as a general approach to enhancing the brightness and analytical performance of fluorescent nanoprobes.",
  "abstract_shown": true,
  "affiliations": [
    "Nano-Science Center and Department of Chemistry",
    "University of Copenhagen",
    "Extreme Light Infrastructure ERIC, ELI Beamlines Facility, Dolní Břežany 252 41, Czech Republic",
    "Department of Chemistry",
    "Indiana University",
    "Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, Copenhagen, Denmark, DK-2100"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Fuxue Zhang"
    },
    {
      "affs": [
        2
      ],
      "name": "Jakub Dostá"
    },
    {
      "affs": [
        2
      ],
      "name": "Andrej Hovan"
    },
    {
      "affs": [
        2
      ],
      "name": "Miroslav Kloz"
    },
    {
      "affs": [
        3,
        4
      ],
      "name": "Amar H. Flood"
    },
    {
      "affs": [
        5
      ],
      "name": "Elisabeth Rexen Ulven"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Bo W. Laursen"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Junsheng Chen",
      "orcid": "0000-0002-2934-8030"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/d7k4ywcamm41h.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15008155/v1",
  "fulltext_url": null,
  "id": "d7k4ywcamm41h",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008155/v1",
  "language": null,
  "licence": "CC-BY-NC-ND",
  "licence_label": "CC BY-NC-ND",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2505|Luminescence and Fluorescent Materials"
    ]
  ],
  "openalex": "W7204861283",
  "pdf_url": "https://chemrxiv.org/doi/pdf/10.26434/chemrxiv.15008155/v1",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/d7k4ywcamm41h.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:17Z",
      "native_id": "10.26434/chemrxiv.15008155",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008155/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2505|Luminescence and Fluorescent Materials",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Capping-Agent Regulation of Exciton Transport in Organic Nanoparticles Enables Ultrabright Flow Cytometry Probes",
  "title_text": "Capping-Agent Regulation of Exciton Transport in Organic Nanoparticles Enables Ultrabright Flow Cytometry Probes",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:17Z",
  "url": "https://research.draconitic.com/paper/d7k4ywcamm41h",
  "venue": "ChemRxiv",
  "versions": []
}