DYNAFLUORS
TM
Dynamic
Fluorophores
Activatable
Optical imaging has revolutionised our understanding of how biological systems behave at a molecular level. In our group we develop Dynamic Activatable Fluorophores (DYNAFLUORS) as chemical probes to image molecular events associated to infection, inflammation and cancer. With DYNAFLUORS, we aim to interrogate fundamental biology in real time as well as provide better tools to diagnose and treat disease in the clinic.
Smart probes for optical imaging of T cells and screening of anti-cancer immunotherapies
Adapted from Chem. Soc. Rev., 2023, 52, 5352 (Royal Society of Chemistry). Illustration by Silvia Dotto
Understanding how immune cells behave within complex tissues requires chemical tools that report cellular function rather than just cell identity. Our research focuses on the design of smart probes that become activated by specific immune cell activities, enabling real-time imaging of immune responses in living systems. By integrating chemical sensing strategies with biologically relevant substrates, we develop probes that translate enzymatic activity, receptor engagement, or immune cell signalling into optical readouts.
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A central direction of our work is the development of activatable chemokine-based probes that exploit immune-cell trafficking pathways for selective targeting. Early work demonstrated a fluorescent AND-gate version of the chemokine CCL2 capable of detecting metastasis-associated macrophages in vivo (Fernandez et al., Angew. Chem. 2019). This strategy was later expanded through enzyme-activatable chemokine conjugates that selectively label tumour-associated macrophages (Barth et al., Angew. Chem. 2022). More recently, receptor-controlled chemokine ligation has enabled bioorthogonal imaging of drug-resistant leukemic B cells (Bertolini et al., JACS 2024) and enzyme-activatable CXCL13 probes have provided direct fluorescence detection of hypoxic B-cell populations (Bertolini et al., JACS 2025).
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Complementing these targeting strategies, we develop activity-based probes that report immune effector functions. Chemiluminescent probes have enabled non-invasive imaging of natural killer cell activity against tumours (Scott et al., Angew. Chem. 2021). Fluorogenic substrates for cytotoxic proteases such as granzyme B allow in-biopsy assessment of response to cancer immunotherapy (Scott et al., Nat. Commun. 2022), while complementary probes targeting granzyme A enable real-time imaging of adaptive immune cell activity (Cheng et al., Angew. Chem. 2023) and clinical assays for monitoring inflammatory bowel disease (Scott et al., Nat. Biomed. Eng. 2026).
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Our group also develops fluorogenic reporters for broader immune-related processes, including probes for drug-induced apoptosis (Barth et al., Nat. Commun. 2020) and near-infrared dyes for functional imaging of ocular inflammation (Thomas et al., Biosens. Bioelectron. 2022). Together, these studies establish a chemical toolkit for visualising immune cell function across cancer, inflammation, and immunotherapy, bridging molecular probe design with translational imaging.
ACTIVATABLE FLUOROPHORES FOR ADVANCED THERAPEUTICS
Miniaturized Chemical Tags for Optical Imaging
Adapted from Angew. Chem. Int. Ed. 2022, 61, e202204788 (Wiley VCH).
The development of modern therapeutics increasingly requires molecular tools that can report drug activity, delivery, and biological response in real time. Our research focuses on the design of activatable fluorophores and fluorogenic labels that remain optically silent until they interact with their biological target or undergo a specific chemical transformation. These systems provide powerful strategies to monitor therapeutic mechanisms, visualise drug–target engagement, and guide the development of next-generation precision medicines.
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One key direction of our work is the creation of fluorogenic probes that report therapeutic efficacy in living systems. Early examples include a bivalent activatable probe for screening and intravital imaging of chemotherapy-induced cancer cell death (Barth et al., Angew. Chem. 2022). Building on this concept, we developed fluorogenic platforms capable of tracking subcellular payload release from antibody–drug conjugates, enabling real-time imaging of intracellular drug activation (Nadal-Bufi et al., JACS 2025).
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A complementary strategy involves minimal and nonperturbative fluorogenic labeling of therapeutic proteins and drug targets. The insertion of OFF-to-ON BODIPY tags into cytokines has enabled the creation of a fluorogenic interleukin-33 that allows real-time imaging of immune cell signalling (Reese et al., ACS Cent. Sci. 2024). Similarly, nonperturbative fluorogenic labeling of immunophilins permits wash-free detection of immunosuppressant binding and drug–target interactions in living cells (Bertolini et al., ACS Cent. Sci. 2024). Related minimal labeling strategies enable late-stage modification of peptides and proteins for real-time imaging of cellular trafficking without altering their biological activity (Nadal-Bufi et al., ACS Cent. Sci. 2025).
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Beyond therapeutic proteins, our work also develops fluorogenic reporters for drug discovery and pharmacology. Drug-derived fluorescent probes have been designed for highly selective visualization of the cannabinoid receptors while chemical engineering approaches have enabled the discovery of cell-permeable modulators of transcription factors (Harel et al., JACS 2025). In parallel, platforms incorporating fluorogenic amino acids facilitate the rapid evolution of nanosensors for biological detection (Kuru et al., Nat. Commun. 2024).
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Finally, we are expanding the optical capabilities of activatable probes through new photophysical concepts, including biocompatible TADF fluorophores for multiplexed fluorescence lifetime imaging (Suárez de Cepeda et al., Angew. Chem. 2026). Together, these studies establish activatable fluorophores as versatile tools to visualise therapeutic mechanisms, quantify drug action, and accelerate translational drug development.
TRANSLATION, TRANSLATION, TRANSLATION
One of our main objectives (and motivations!) is to deliver high-impact translational research by working with clinicians to bring new imaging probes to clinical trials and with industry to commercialise new technologies.