All Publications

  • In vivo non-invasive confocal fluorescence imaging beyond 1,700 nm using superconducting nanowire single-photon detectors. Nature nanotechnology Wang, F., Ren, F., Ma, Z., Qu, L., Gourgues, R., Xu, C., Baghdasaryan, A., Li, J., Zadeh, I. E., Los, J. W., Fognini, A., Qin-Dregely, J., Dai, H. 2022


    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

  • Probing dissolved CO2(aq) in aqueous solutions for CO2 electroreduction and storage. Science advances Li, J., Guo, J., Dai, H. 2022; 8 (19): eabo0399


    CO2 dissolved in aqueous solutions CO2(aq) is important to CO2 capture, storage, photo-/electroreduction in the fight against global warming and to CO2 analysis in drinks. Here, we developed microscale infrared (IR) spectroscopy for in situ dynamic quantitating CO2(aq). The quantized CO2(g) rotational state transitions were observed to quench for CO2(aq), accompanied by increased H2O IR absorption. An accurate CO2 molar extinction coefficient ε was derived for in situ CO2(aq) quantification up to 58 atm. We directly measured CO2(aq) concentrations in electrolytes under CO2(g) bubbling and high-pressure conditions with high spectral and time resolutions. In KHCO3 electrolytes with CO2(aq) > ~1 M, CO2 electroreduction (CO2RR) to formate reached >98% Faradaic efficiencies on copper (Cu2O/Cu)-based electrocatalyst. Furthermore, CO2 dissolution/desolvation kinetics showed large hysteresis and ultraslow reversal of CO2(aq) supersaturation in aqueous systems, with implications to CO2 capture, storage, and supersaturation phenomena in natural water bodies.

    View details for DOI 10.1126/sciadv.abo0399

    View details for PubMedID 35559679

  • 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 Wang, F., Qu, L., Ren, F., Baghdasaryan, A., Jiang, Y., Hsu, R., Liang, P., Li, J., Zhu, G., Ma, Z., Dai, H. 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

  • Rechargeable Na/Cl2 and Li/Cl2 batteries. Nature Zhu, G., Tian, X., Tai, H., Li, Y., Li, J., Sun, H., Liang, P., Angell, M., Huang, C., Ku, C., Hung, W., Jiang, S., Meng, Y., Chen, H., Lin, M., Hwang, B., Dai, H. 2021; 596 (7873): 525-530


    Lithium-ion batteries (LIBs) are widely used in applications ranging from electric vehicles to wearable devices. Before the invention of secondary LIBs, the primary lithium-thionyl chloride (Li-SOCl2) battery was developed in the 1970s using SOCl2 as the catholyte, lithium metal as the anode and amorphous carbon as the cathode1-7. This battery discharges by lithium oxidation and catholyte reduction to sulfur, sulfur dioxide and lithium chloride, is well known for its high energy density and is widely used in real-world applications; however, it has not been made rechargeable since its invention8-13. Here we show that with a highly microporous carbon positive electrode, a starting electrolyte composed of aluminium chloride in SOCl2 with fluoride-based additives, and either sodium or lithium as the negative electrode, we can produce a rechargeable Na/Cl2 or Li/Cl2 battery operating via redox between mainly Cl2/Cl- in the micropores of carbon and Na/Na+ or Li/Li+ redox on the sodium or lithium metal. The reversible Cl2/NaCl or Cl2/LiCl redox in the microporous carbon affords rechargeability at the positive electrodeside and the thin alkali-fluoride-doped alkali-chloride solid electrolyte interfacestabilizesthe negative electrode, both are critical to secondary alkali-metal/Cl2 batteries.

    View details for DOI 10.1038/s41586-021-03757-z

    View details for PubMedID 34433941

  • Selective and High Current CO2 Electro-Reduction to Multicarbon Products in Near-Neutral KCl Electrolytes. Journal of the American Chemical Society Zhang, X., Li, J., Li, Y., Jung, Y., Kuang, Y., Zhu, G., Liang, Y., Dai, H. 2021


    Reducing CO2 to value-added multicarbon (C2+) fuels and chemicals using renewable energy is a viable way to circumvent CO2 buildup in the atmosphere and facilitate closing the carbon cycle. To date it remains a challenge to achieve high product selectivity and long-term stability of electrocatalytic carbon dioxide reduction reaction (CO2RR) especially at practically relevant high current levels >100 mA cm-2. Here, we report a simple electrodeposited Cu electrocatalyst on a hydrophobic porous gas-diffusion layer (GDL) electrode affording stable and selective CO2RR to C2+ products in near-neutral KCl electrolytes. By directing the CO2 stream to fully submerged hydrophobic GDLs in a H-cell, high C2+ partial current densities near 100 mA cm-2 were achieved. In a flow-cell setup, the Cu/GDL cathode in 2 M KCl afforded stable CO2RR superior to that in widely used KOH electrolytes. We found that Cu etching/corrosion associated with trace oxygen played a role in the catalyst instability in alkaline media under cathodic CO2RR conditions, a problem largely suppressed in near-neutral electrolyte. A two-electrode CO2 electrolyzer was constructed with a Cu/GDL cathode in KCl catholyte and an anode comprised of nickel-iron hydroxide on nickel foam (NiFe/NF) in a KOH anolyte separated by Nafion membrane. By periodically adding HCl to the KCl catholyte to compensate the increasing pH and remove accumulated (bi)carbonates, we observed little decay over 30 h in flow-cell CO2RR activity and selectivity at 150 mA cm-2 with a high Faradaic efficiency (FE) of 75% and energy efficiency of 40% for C2+ products.

    View details for DOI 10.1021/jacs.0c13427

    View details for PubMedID 33617245

  • Cross-Link-Functionalized Nanoparticles for Rapid Excretion in Nanotheranostic Applications. Angewandte Chemie (Weinheim an der Bergstrasse, Germany) Ma, Z., Wang, F., Zhong, Y., Salazar, F., Li, J., Zhang, M., Ren, F., Wu, A. M., Dai, H. 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

  • A high-performance potassium metal battery using safe ionic liquid electrolyte. Proceedings of the National Academy of Sciences of the United States of America Sun, H., Liang, P., Zhu, G., Hung, W. H., Li, Y., Tai, H., Huang, C., Li, J., Meng, Y., Angell, M., Wang, C., Dai, H. 2020


    Potassium secondary batteries are contenders of next-generation energy storage devices owing to the much higher abundance of potassium than lithium. However, safety issues and poor cycle life of K metal battery have been key bottlenecks. Here we report an ionic liquid electrolyte comprising 1-ethyl-3-methylimidazolium chloride/AlCl3/KCl/potassium bis(fluorosulfonyl) imide for safe and high-performance batteries. The electrolyte is nonflammable and exhibits a high ionic conductivity of 13.1 mS cm-1 at room temperature. A 3.6-V battery with K anode and Prussian blue/reduced graphene oxide cathode delivers a high energy and power density of 381 and 1,350 W kg-1, respectively. The battery shows an excellent cycling stability over 820 cycles, retaining 89% of the original capacity with high Coulombic efficiencies of 99.9%. High cyclability is also achieved at elevated temperatures up to 60 °C. Uniquely, robust K, Al, F, and Cl-containing passivating interphases are afforded with this electrolyte, which is key to superior battery cycling performances.

    View details for DOI 10.1073/pnas.2012716117

    View details for PubMedID 33106405

  • Electroreduction of CO2 to Formate on a Copper-Based Electrocatalyst at High Pressures with High Energy Conversion Efficiency. Journal of the American Chemical Society Li, J. n., Kuang, Y. n., Meng, Y. n., Tian, X. n., Hung, W. H., Zhang, X. n., Li, A. n., Xu, M. n., Zhou, W. n., Ku, C. S., Chiang, C. Y., Zhu, G. n., Guo, J. n., Sun, X. n., Dai, H. n. 2020


    Electrocatalytic CO2 reduction (CO2RR) to valuable fuels is a promising approach to mitigate energy and environmental problems, but controlling the reaction pathways and products remains challenging. Here a novel Cu2O nanoparticle film was synthesized by square-wave (SW) electrochemical redox cycling of high-purity Cu foils. The cathode afforded up to 98% Faradaic efficiency for electroreduction of CO2 to nearly pure formate under ≥45 atm CO2 in bicarbonate catholytes. When this cathode was paired with a newly developed NiFe hydroxide carbonate anode in KOH/borate anolyte, the resulting two-electrode high-pressure electrolysis cell achieved high energy conversion efficiencies of up to 55.8% stably for long-term formate production. While the high-pressure conditions drastically increased the solubility of CO2 to enhance CO2 reduction and suppress hydrogen evolution, the (111)-oriented Cu2O film was found to be important to afford nearly 100% CO2 reduction to formate. The results have implications for CO2 reduction to a single liquid product with high energy conversion efficiency.

    View details for DOI 10.1021/jacs.0c00122

    View details for PubMedID 32250611

  • In vivo molecular imaging for immunotherapy using ultra-bright near-infrared-IIb rare-earth nanoparticles. Nature biotechnology Zhong, Y., Ma, Z., Wang, F., Wang, X., Yang, Y., Liu, Y., Zhao, X., Li, J., Du, H., Zhang, M., Cui, Q., Zhu, S., Sun, Q., Wan, H., Tian, Y., Liu, Q., Wang, W., Garcia, K. C., Dai, H. 2019


    The near-infrared-IIb (NIR-IIb) (1,500-1,700nm) window is ideal for deep-tissue optical imaging in mammals, but lacks bright and biocompatible probes. Here, we developed biocompatible cubic-phase (alpha-phase) erbium-based rare-earth nanoparticles (ErNPs) exhibiting bright downconversion luminescence at ~1,600nm for dynamic imaging of cancer immunotherapy in mice. We used ErNPs functionalized with cross-linked hydrophilic polymer layers attached to anti-PD-L1 (programmed cell death-1 ligand-1) antibody for molecular imaging of PD-L1 in a mouse model of colon cancer and achieved tumor-to-normal tissue signal ratios of ~40. The long luminescence lifetime of ErNPs (~4.6ms) enabled simultaneous imaging of ErNPs and lead sulfide quantum dots emitting in the same ~1,600nm window. In vivo NIR-IIb molecular imaging of PD-L1 and CD8 revealed cytotoxic T lymphocytes in the tumor microenvironment in response to immunotherapy, and altered CD8 signals in tumor and spleen due to immune activation. The cross-linked functionalization layer facilitated 90% ErNP excretion within 2weeks without detectable toxicity in mice.

    View details for DOI 10.1038/s41587-019-0262-4

    View details for PubMedID 31570897

  • A safe and non-flammable sodium metal battery based on an ionic liquid electrolyte. Nature communications Sun, H., Zhu, G., Xu, X., Liao, M., Li, Y., Angell, M., Gu, M., Zhu, Y., Hung, W. H., Li, J., Kuang, Y., Meng, Y., Lin, M., Peng, H., Dai, H. 2019; 10 (1): 3302


    Rechargeable sodium metal batteries with high energy density could be important to a wide range of energy applications in modern society. The pursuit of higher energy density should ideally come with high safety, a goal difficult for electrolytes based on organic solvents. Here we report a chloroaluminate ionic liquid electrolyte comprised of aluminium chloride/1-methyl-3-ethylimidazolium chloride/sodium chloride ionic liquid spiked with two important additives, ethylaluminum dichloride and 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide. This leads to the first chloroaluminate based ionic liquid electrolyte for rechargeable sodium metal battery. The obtained batteries reached voltages up to ~4V, high Coulombic efficiency up to 99.9%, and high energy and power density of ~420Whkg-1 and ~1766 W kg-1, respectively. The batteries retained over 90% of the original capacity after 700 cycles, suggesting an effective approach to sodium metal batteries with high energy/high power density, long cycle life and high safety.

    View details for DOI 10.1038/s41467-019-11102-2

    View details for PubMedID 31341162

  • Sono-optogenetics facilitated by a circulation-delivered rechargeable light source for minimally invasive optogenetics. Proceedings of the National Academy of Sciences of the United States of America Wu, X. n., Zhu, X. n., Chong, P. n., Liu, J. n., Andre, L. N., Ong, K. S., Brinson, K. n., Mahdi, A. I., Li, J. n., Fenno, L. E., Wang, H. n., Hong, G. n. 2019


    Optogenetics, which uses visible light to control the cells genetically modified with light-gated ion channels, is a powerful tool for precise deconstruction of neural circuitry with neuron-subtype specificity. However, due to limited tissue penetration of visible light, invasive craniotomy and intracranial implantation of tethered optical fibers are usually required for in vivo optogenetic modulation. Here we report mechanoluminescent nanoparticles that can act as local light sources in the brain when triggered by brain-penetrant focused ultrasound (FUS) through intact scalp and skull. Mechanoluminescent nanoparticles can be delivered into the blood circulation via i.v. injection, recharged by 400-nm photoexcitation light in superficial blood vessels during circulation, and turned on by FUS to emit 470-nm light repetitively in the intact brain for optogenetic stimulation. Unlike the conventional "outside-in" approaches of optogenetics with fiber implantation, our method provides an "inside-out" approach to deliver nanoscopic light emitters via the intrinsic circulatory system and switch them on and off at any time and location of interest in the brain without extravasation through a minimally invasive ultrasound interface.

    View details for DOI 10.1073/pnas.1914387116

    View details for PubMedID 31811026

  • Monolithic Neat Graphene Oxide Aerogel for Efficient Catalysis of S -> O Acetyl Migration ACS CATALYSIS Peng, L., Zheng, Y., Li, J., Jin, Y., Gao, C. 2015; 5 (6): 3387–92
  • Discovery of neat silica gel as a catalyst: an example of S -> O acetyl migration reaction CHEMICAL COMMUNICATIONS Jin, Y., Li, J., Peng, L., Gao, C. 2015; 51 (84): 15390–93


    Silica gel, widely used in chromatography separation and as a catalyst carrier, was employed here for the first time as a fixed-bed catalyst for the S → O acetyl migration to synthesize thiol compounds under mild conditions, showing the merits of high efficiency, high selectivity, long-life recyclability, low cost and scalable availability.

    View details for DOI 10.1039/c5cc05396j

    View details for Web of Science ID 000363167600009

    View details for PubMedID 26344918