Hongjie Dai, Postdoctoral Faculty Sponsor
In vivo non-invasive confocal fluorescence imaging beyond 1,700 nm using superconducting nanowire single-photon detectors.
Light scattering by biological tissues sets a limit to the penetration depth of high-resolution optical microscopy imaging of live mammals in vivo. An effective approach to reduce light scattering and increase imaging depth is to extend the excitation and emission wavelengths to the second near-infrared window (NIR-II) at >1,000 nm, also called the short-wavelength infrared window. Here we show biocompatible core-shell lead sulfide/cadmium sulfide quantum dots emitting at ~1,880 nm and superconducting nanowire single-photon detectors for single-photon detection up to 2,000 nm, enabling a one-photon excitation fluorescence imaging window in the 1,700-2,000 nm (NIR-IIc) range with 1,650 nm excitation-the longest one-photon excitation and emission for in vivo mouse imaging so far. Confocal fluorescence imaging in NIR-IIc reached an imaging depth of ~1,100 μm through an intact mouse head, and enabled non-invasive cellular-resolution imaging in the inguinal lymph nodes of mice without any surgery. We achieve in vivo molecular imaging of high endothelial venules with diameters as small as ~6.6 μm, as well as CD169 + macrophages and CD3 + T cells in the lymph nodes, opening the possibility of non-invasive intravital imaging of immune trafficking in lymph nodes at the single-cell/vessel-level longitudinally.
View details for DOI 10.1038/s41565-022-01130-3
View details for PubMedID 35606441
Phosphorylcholine-conjugated gold-molecular clusters improve signal for Lymph Node NIR-II fluorescence imaging in preclinical cancer models.
2022; 13 (1): 5613
Sentinel lymph node imaging and biopsy is important to clinical assessment of cancer metastasis, and novel non-radioactive lymphographic tracers have been actively pursued over the years. Here, we develop gold molecular clusters (Au25) functionalized by phosphorylcholine (PC) ligands for NIR-II (1000-3000nm) fluorescence imaging of draining lymph nodes in 4T1 murine breast cancer and CT26 colon cancer tumor mouse models. The Au-phosphorylcholine (Au-PC) probes exhibit 'super-stealth' behavior with little interactions with serum proteins, cells and tissues in vivo, which differs from the indocyanine green (ICG) dye. Subcutaneous injection of Au-PC allows lymph node mapping by NIR-II fluorescence imaging at an optimal time of ~ 0.5 - 1hour postinjection followed by rapid renal clearance. Preclinical NIR-II fluorescence LN imaging with Au-PC affords high signal to background ratios and high safety and biocompatibility, promising for future clinical translation.
View details for DOI 10.1038/s41467-022-33341-6
View details for PubMedID 36153336
High-precision tumor resection down to few-cell level guided by NIR-IIb molecular fluorescence imaging.
Proceedings of the National Academy of Sciences of the United States of America
2022; 119 (15): e2123111119
SignificanceSurgical removal of tumors has been performed to combat cancer for over a century by surgeons relying on visual inspection and experience to identify margins between malignant and healthy tissues. Herein, we present a rare-earth down-conversion nanoparticle-anti-CD105 conjugate for cancer targeting and a handheld imager capable of concurrent photographic imaging and fluorescence/luminescence imaging. An unprecedented tumor-to-muscle ratio was achieved by near-infrared-IIb (NIR-IIb, 1,500 to 1,700 nm) imaging during surgery, 100 times higher than previous organic dyes for unambiguous determination of tumor margin. The sensitivity/biocompatibility/safety of the probes and instrumentation developed here open a paradigm of imaging-guided surgery at the single-cell level, meeting all major requirements for clinical translation to combat cancer and save human lives.
View details for DOI 10.1073/pnas.2123111119
View details for PubMedID 35380898
In vivo NIR-II structured-illumination light-sheet microscopy.
Proceedings of the National Academy of Sciences of the United States of America
2021; 118 (6)
Noninvasive optical imaging with deep tissue penetration depth and high spatiotemporal resolution is important to longitudinally studying the biology at the single-cell level in live mammals, but has been challenging due to light scattering. Here, we developed near-infrared II (NIR-II) (1,000 to 1,700 nm) structured-illumination light-sheet microscopy (NIR-II SIM) with ultralong excitation and emission wavelengths up to 1,540 and 1,700 nm, respectively, suppressing light scattering to afford large volumetric three-dimensional (3D) imaging of tissues with deep-axial penetration depths. Integrating structured illumination into NIR-II light-sheet microscopy further diminished background and improved spatial resolution by approximately twofold. In vivo oblique NIR-II SIM was performed noninvasively for 3D volumetric multiplexed molecular imaging of the CT26 tumor microenvironment in mice, longitudinally mapping out CD4, CD8, and OX40 at the single-cell level in response to immunotherapy by cytosine-phosphate-guanine (CpG), a Toll-like receptor 9 (TLR-9) agonist combined with OX40 antibody treatment. NIR-II SIM affords an additional tool for noninvasive volumetric molecular imaging of immune cells in live mammals.
View details for DOI 10.1073/pnas.2023888118
View details for PubMedID 33526701
Cross-Link-Functionalized Nanoparticles for Rapid Excretion in Nanotheranostic Applications.
Angewandte Chemie (Weinheim an der Bergstrasse, Germany)
2020; 132 (46): 20733-20741
Most NIR-IIb fluorophores are nanoparticle-based probes with long retention ( 1 month or longer) in the body. Here, we applied a novel cross-linked coating to functionalize core/shell lead sulfide/cadmium sulfide quantum dots (PbS/CdS QDs) emitting at 1600 nm. The coating was comprised of an amphiphilic polymer followed by three crosslinked amphiphilic polymeric layers (P3 coating), imparting high biocompatibility and > 90% excretion of QDs within 2 weeks of intravenous administration. The P3-QDs were conjugated to an engineered anti-CD8 diabody (Cys-diabody) for in vivo molecular imaging of CD8 + cytotoxic T lymphocytes (CTLs) in response to anti-PD-L1 therapy. Two-plex molecular imaging in combination with down-conversion Er nanoparticles (ErNPs) was performed for real-time in vivo monitoring of PD-L1 positive tumor cells and CTLs with cellular resolution by non-invasive NIR-IIb light sheet microscopy. Imaging of angiogenesis in the tumor microenvironment and of lymph nodes deep in the body with a signal-to-background ratio of up to 170 was also achieved using P3-QDs.
View details for DOI 10.1002/ange.202008083
View details for PubMedID 34334834
Advancing nanomedicine with cross-link functionalized nanoparticles for rapid excretion.
Angewandte Chemie (International ed. in English)
Nanoparticles have been widely investigated for preclinical animal models as imaging, therapeutic or theranostic agent. However, a very limited number of nanoscale materials are approved for human use due to retention and toxicity concerns. Recent years have seen in vivo fluorescence imaging in the long end of the second near infrared window (NIR-IIb, 1,500-1,700 nm), affording deeper tissue penetration and higher imaging clarity owing to reduced light scattering and near-zero autofluorescence. Most NIR-IIb fluorophores are nanoparticle based probes with long retentionin the body. Here, we applied a novel cross-linked coating to functionalize core/shell lead sulfide/cadmium sulfide quantum dots (PbS/CdS QDs) emitting at ~1,600 nm. The coating was comprised of an amphiphilic polymer followed by three crosslinked amphiphilic polymeric layers (branched PEG-linear PAA-branched PEG, P 3 coating), imparting high biocompatibility and > 90% excretion of QDs within 2 weeks of intravenous administration. The P 3 -QDs were utilized for conjugation to an engineered anti-CD8 diabody to afford in vivo molecular imaging of CD8+ cytotoxic T lymphocytes (CTLs) in response to anti-PD-L1 therapy. Two-plex molecular imaging in combination with down-conversion Er nanoparticles was performed for real-time in vivo monitoring of PD-L1+tumor cells and CD8+CTLswith cellular resolution by non-invasive NIR-IIb light sheet microscopy (LSM). In another application, angiogenesis in the tumor microenvironment was imaged with P 3 -QDs conjugated to TRC105, a chimeric monoclonal antibody against CD105. Further, P 3 -QDs afforded imaging of lymph nodes deep in the body with a signal-to-background ratio of up to ~170. Lastly, we show that the P 3 coating on magnetic nanoparticles also afforded rapid excretion in < 2 weeks, establishing generality of the approach. The ability of eliminating various nanoparticles from a body opens up many possibilities of nanomedicine for human use.
View details for DOI 10.1002/anie.202008083
View details for PubMedID 32681553