In situ orderly self-assembly strategy affording NIR-II-J-aggregates for in vivo imaging and surgical navigation.

J-aggregation, an effective strategy to extend wavelength, has been considered as a promising method for constructing NIR-II fluorophores. However, due to weak intermolecular interactions, conventional J-aggregates are easily decomposed into monomers in the biological environment. Although adding external carriers could help conventional J-aggregates stabilize, such methods still suffer from high-concentration dependence and are unsuitable for activatable probes design. Besides, these carriers-assisted nanoparticles are risky of disassembly in lipophilic environment. Herein, by fusing the precipitated dye (HPQ) which has orderly self-assembly structure, onto simple hemi-cyanine conjugated system, we construct a series of activatable, high-stability NIR-II-J-aggregates which overcome conventional J-aggregates carrier's dependence and could in situ self-assembly in vivo. Further, we employ the NIR-II-J-aggregates probe HPQ-Zzh-B to achieve the long-term in situ imaging of tumor and precise tumor resection by NIR-II imaging navigation for reducing lung metastasis. We believe this strategy will advance the development of controllable NIR-II-J-aggregates and precise bioimaging in vivo.

Tuning the Cellular Uptake and Retention of Rhodamine Dyes by Molecular Engineering for High-Contrast Imaging of Cancer Cells.

Probes allowing high-contrast discrimination of cancer cells and effective retention are powerful tools for the early diagnosis and treatment of cancer. However, conventional small-molecule probes often show limited performance in both aspects. Herein, we report an ingenious molecular engineering strategy for tuning the cellular uptake and retention of rhodamine dyes. Introduction of polar aminoethyl leads to the increased brightness and reduced cellular uptake of dyes, and this change can be reversed by amino acetylation. Moreover, these modifications allow cancer cells to take up more dyes than normal cells (16-fold) through active transport. Specifically, we further improve the signal contrast (56-fold) between cancer and normal cells by constructing activatable probes and confirm that the released fluorophore can remain in cancer cells with extended time, enabling long-term and specific tumor imaging.

"Four-In-One" Design of a Hemicyanine-Based Modular Scaffold for High-Contrast Activatable Molecular Afterglow Imaging.

Afterglow luminescence (long persistent luminescence) holds great potential for nonbackground molecular imaging. However, current afterglow probes are mainly nanoparticles, and afterglow imaging systems based on organic small molecules are still lacking and have rarely been reported. Moreover, the lack of reactive sites and a universal molecular scaffold makes it difficult to design activatable afterglow probes. To address these issues, this study reports a novel kind of hemicyanine-based molecule scaffolds with stimuli-responsive afterglow luminescence, which is dependent on an intramolecular cascade photoreaction between 1O2 and the afterglow molecule to store the photoenergy for delayed luminescence after light cessation. As a proof of concept, three modular activatable molecular afterglow probes (MAPs) with a "four-in-one" molecular design by integrating a stimuli-responsive unit, 1O2-generating unit, 1O2-capturing unit, and luminescent unit into one probe are customized for quantification and imaging of targets including pH, superoxide anions, and aminopeptidase. Notably, MAPs show higher sensitivity in afterglow imaging than in fluorescence imaging because the responsive unit simultaneously controls the initiation of fluorescence (S1 to S0) and 1O2 generation (S1 to T1). Finally, MAPs are applied for high-contrast afterglow imaging of drug-induced hepatotoxicity, which is poorly evaluated in clinics and drug discovery. By reporting the sequential occurrence of oxidative stress and upregulation of aminopeptidase, such activatable afterglow probes allow noninvasive imaging of hepatotoxicity earlier than the serological and histology manifestation, indicating their promise for early diagnosis of hepatotoxicity.

Engineering of a novel D-A type fluorophore with hydrogen bond-induced enhanced emission property for sensitively detecting endogenous HOCl in living cells and tissues.

Fluorescence imaging has been widely employed for biomedical research and clinical diagnostics. With ease of synthesis and excellent photophysical properties, D-A type fluorophores are widely designed for fluorescence imaging. However, traditional D-A type fluorophores are solvatochromic which reduces the fluorescence brightness in the biological system. To solve this problem and build on our previous work, we devised a novel HIEE fluorophore MTC with typical anti-solvatochromic fluorescence. Furthermore, the activated fluorescent probe designed based on MTC showed excellent imaging performance. We believe that the strategy based on the fluorophores with typical anti-solvatohromic fluorescence can be a useful platform for designing fluorescent probes for high-brightness imaging in the biological system.

High-fidelity imaging of lysosomal enzyme through in situ ordered assembly of small molecular fluorescent probes.

As an organelle in cells, lysosomes play an important role in the degradation of biological macromolecules and pathogens. To elucidate the function of lysosomes in normal or disease states, recently, various fluorescent probes have been reported for imaging lysosomal analytes. However, because of the particularity of the lysosomal environment, most of the reported lysosomal fluorescent probes suffered from a series of practical issues such as easy diffusion, low detection signal-to-background ratio and false signal. To address these issues, based on an optimized in situ ordered assembly solid-state fluorophore HDPQ, we herein put forward a new strategy for the design of lysosomal enzymes probes. As a proof concept, we synthesized a fluorescent probe HDPQ-GLU for lysosomal enzyme ß-glucuronidase (GLU). Experiment results displayed that compared with general lysosomal probe, the novel lysosomal probe not only exhibited excellent anti-pH interference ability and high signal-to-noise ratio in aqueous solution, but also has excellent long-term in situ imaging ability in the living system. Using this probe, we have realized high-fidelity and long-term in situ tracking GLU in lysosomes of living cells and evaluated the dynamic changes of GLU during the growth period of zebrafish. We anticipate that the new strategy based on the novel in situ ordered assembly solid-state fluorophore HDPQ may be a potential platform for developing fluorescent probes for high-fidelity imaging of lysosomal enzymes.

Imaging of peroxynitrite in drug-induced acute kidney injury with a near-infrared fluorescence and photoacoustic dual-modal molecular probe.

A FRET-based probe for mapping the fluctuation of ONOO- in cisplatin-induced acute kidney injury was constructed. It exhibits ratiometric near infrared fluorescence and a dramatic decrease of its peak absorbance at 719 nm upon addition of ONOO- that is converted into remarkable signal changes in fluorescence and photoacoustic images respectively.

pH stimulus-disaggregated BODIPY: an activated photodynamic/photothermal sensitizer applicable to tumor ablation.

Herein, we report a pH stimulus-disaggregated BODIPY sensitizer (PTS) with low background-toxicity for achieving activated photodynamic/photothermal tumor therapy. Both the photodynamic and photothermal properties of PTS can be activated under acidic conditions, and PTS exhibits excellent antitumor properties, which is revealed by both in vitro and in vivo tests.

90-gene signature assay for tissue origin diagnosis of brain metastases.

BACKGROUND: Brain metastases (BM) are the most common intracranial tumors. 2-14% of BM patients present with unknown primary site despite intensive evaluations. This study aims to evaluate the performance of a 90-gene expression signature in determining the primary sites for BM samples. METHODS: The sequence-based gene expression profiles of 708 primary brain tumors (PBT) collected from The Cancer Genome Atlas (TCGA) database were analyzed by the 90-gene expression signature, with a similarity score for each of 21 common tumor types. We then used Optimal Binning algorithm to generate a threshold for separating PBT from BM. Eighteen PBT samples were analyzed to substantiate the reliability of the threshold. In addition, the performance of the 90-gene expression signature for molecular classification of metastatic brain tumors was validated in a cohort of 48 BM samples with the known origin. For each BM sample, the tumor type with the highest similarity score was considered tissue of origin. When a sample was diagnosed as PBT, but the similarity score below the threshold, the second prediction was considered as the primary site. RESULTS: A threshold of the similarity score, 70, was identified to discriminate PBT from BM (PBT: > 70, BM: ≤ 70) with an accuracy of 99% (703/708, 95% CI 98-100%). The 90-gene expression signature was further validated with 18 PBT and 44 BM samples. The results of 18 PBT samples matched reference diagnosis with a concordance rate of 100%, and all similarity scores were above the threshold. Of 44 BM samples, the 90-gene expression signature accurately predicted primary sites in 89% (39/44, 95% CI 75-96%) of the cases. CONCLUSIONS: Our findings demonstrated the potential that the 90-gene expression signature could serve as a powerful tool for accurately identifying the primary sites of metastatic brain tumors.

Gestational age-specific reference intervals for blood copper, zinc, calcium, magnesium, iron, lead, and cadmium during normal pregnancy.

OBJECTIVES: The aim of this study was to investigate the blood copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), iron (Fe), lead (Pb), and cadmium (Cd) concentrations in women of ≤12 (group I), 13-20 (group II), 21-27 (group III), 28-35 (group IV), and 36-42 (group V) weeks of gestation and compare them with those in nonpregnant women. DESIGN AND METHODS: The cross-sectional study was performed in 2380 pregnant women [group I (n = 550); group II (n = 552); group III (n = 600); group IV (n = 553); and group V (n = 125)] and 552 nonpregnant women as controls. Blood seven element concentrations, including Cu, Zn, Ca, Mg, Fe, Pd, and Cd, were determined by atomic absorption spectrometry (AAS). RESULTS: Compared with the nonpregnant women group, the concentrations of Cu, Zn, Ca, Mg, Fe, Pb, and Cd at ≤12, 13-20, 21-27, 28-35, and 36-42 weeks of gestation, on the whole, were significantly different. Blood Cu, Mg, Ca, Fe, Pb, and Cd concentrations were correlated with weeks of gestation (P<0.05). The gestational age-specific reference intervals were established for Cu, Zn, Ca, Mg, Fe, Pd, and Cd. CONCLUSIONS: The established reference intervals for Cu, Zn, Ca, Mg, and Fe can provide important guidance for the reasonable supplementation of essential elements in pregnancy. And the reference intervals for Pd and Cd can play an important part in the surveillance and diagnosis of environmental overexposure.