Lymph node metastasis is a major metastatic route of cancer and significantly influences the prognosis of cancer patients. Radical lymphadenectomy is crucial for a successful surgery. However, ...iatrogenic normal organ injury during lymphadenectomy is a troublesome complication. Here, this paper reports a kind of organic nanoprobes (IDSe‐IC2F nanoparticles (NPs)) with excellent second near‐infrared (NIR‐II) fluorescence and photothermal properties. IDSe‐IC2F NPs can effectively label lymph nodes and helped achieve high‐contrast lymphatic imaging. More importantly, by jointly using IDSe‐IC2F nanoparticles and other kinds of nanoparticles with different excitation/emission properties, a multichannel NIR‐II fluorescence imaging modality and imaging‐guided lymphadenectomy is proposed. With the help of this navigation system, the iatrogenic injury can be largely avoided. In addition, NIR‐II fluorescence imaging‐guided photothermal treatment (“hot” strategy) can ablate those metastatic lymph nodes which are difficult to deal with during resection (“cold” strategy). Nanoprobes‐assisted and multichannel NIR‐II fluorescence imaging‐guided “cold” and “hot” treatment strategy provides a general new basis for the future precision surgery.
A novel kind of second near‐infrared (NIR‐II) fluorescent nanoprobe is synthesized to label and trace lymph nodes (LNs). Together with other kinds of NIR‐II fluorescent NPs with different optical features, multichannel fluorescence imaging‐guided surgeries are successfully conducted. Photothermal ablation of metastatic LNs is introduced as a good complement to surgery. This platform offers a novel perspective through which a more precise surgery can be conducted.
Huanglongbing (HLB) is one of the most destructive diseases of citrus, which has posed a serious threat to the global citrus production. This research was aimed to explore the use of chlorophyll ...fluorescence imaging combined with feature selection to characterize and detect the HLB disease. Chlorophyll fluorescence images of citrus leaf samples were measured by an in-house chlorophyll fluorescence imaging system. The commonly used chlorophyll fluorescence parameters provided the first screening of HLB disease. To further explore the photosynthetic fingerprint of HLB infected leaves, three feature selection methods combined with the supervised classifiers were employed to identify the unique fluorescence signature of HLB and perform the three-class classification (i.e., healthy, HLB infected, and nutrient deficient leaves). Unlike the commonly used fluorescence parameters, this novel data-driven approach by using the combination of the mean fluorescence parameters and image features gave the best classification performance with the accuracy of 97%, and presented a better interpretation for the spatial heterogeneity of photochemical and non-photochemical components in HLB infected citrus leaves. These results imply the potential of the proposed approach for the citrus HLB disease diagnosis, and also provide a valuable insight for the photosynthetic response to the HLB disease.
Abstract
Bright anti-Stokes fluorescence (ASF) in the first near-infrared spectral region (NIR-I, 800 nm–900 nm) under the excitation of a 915 nm continuous wave (CW) laser, is observed in ...Indocyanine Green (ICG), a dye approved by the Food and Drug Administration for clinical use. The dependence of fluorescence intensity on excitation light power and temperature, together with fluorescence lifetime measurement, establish this ASF to be originated from absorption from a thermally excited vibrational level (hot-band absorption), as shown in our experiments, which is stronger than the upconversion fluorescence from widely-used rare-earth ion doped nanoparticles. To test the utility of this ASF NIR-I probe for advanced bioimaging, we successively apply it for biothermal sensing, cerebral blood vessel tomography and blood stream velocimetry. Moreover, in combination with L1057 nanoparticles, which absorb the ASF of ICG and emit beyond 1100 nm, these two probes generate multi-mode images in two fluorescent channels under the excitation of a single 915 nm CW laser. One channel is used to monitor two overlapping organs, urinary system & blood vessel of a live mouse, while the other shows urinary system only. Using in intraoperative real-time monitoring, such multi-mode imaging method can be beneficial for visual guiding in anatomy of the urinary system to avoid any accidental injury to the surrounding blood vessels during surgery.
Lipid droplets (LDs) participate in many physiological processes, the abnormality of which will cause chronic diseases and pathologies such as diabetes and obesity. It is crucial to monitor the ...distribution of LDs at high spatial resolution and large depth. Herein, we carried three-photon imaging of LDs in fat liver. Owing to the large three-photon absorption cross-section of the luminogen named NAP-CF
3
(Formula: see textFormula: see textcm
6
s
2
), three-photon fluorescence fat liver imaging reached the largest depth of 80Formula: see textFormula: see textm. Fat liver diagnosis was successfully carried out with excellent performance, providing great potential for LDs-associated pathologies research.
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•Sucrose in HLB infected leaves accumulated more steadily than other carbohydrates, while Fe deficient leaves presented a reverse pattern.•Spectral and textural features from optimal ...spectral and PC images were well linked to the HLB disease fingerprint in different seasons.•The robustness of model was validated by a different cultivar using model transfer strategy with the overall classification accuracy of 93.5%.
Huanglongbing (HLB) is a highly destructive disease to citrus that is threatening the global citrus industry. It is a great challenge for HLB disease detection at various stages due to the long asymptomatic period and the similar symptom to nutrient deficient trees. This research was aimed to propose an effective method for HLB detection in different seasons and cultivars based on hyperspectral imaging coupled with carbohydrate metabolism analysis. It was found that sucrose accumulated more steadily than starch, glucose and fructose in infected leaves through the hot and cool seasons, but nutrient (Fe) deficient leaves presented a reverse pattern to HLB infected leaves. Spectral and textural features from optimal wavelengths and principle component images were well linked to the HLB fingerprint. The three-class classification models for healthy, HLB infected (asymptomatic and symptomatic), and nutrient deficient leaves achieved 90.2%, 96.0%, and 92.6% accuracy for the cool season, hot season, and the whole period, respectively, using least squares-support vector machine (LS-SVM) classifier. Additionally, the robustness of classification model was validated by a different citrus cultivar using model transfer strategy with the overall accuracy of 93.5%. These results demonstrated the potential of hyperspectral imaging combined with carbohydrate metabolic analysis for HLB detection in different seasons and cultivars.
Three-photon fluorescence microscopic (3PFM) bioimaging is a promising imaging technique for visualizing the brain in its native environment thanks to its advantages of high spatial resolution and ...large imaging depth. However, developing fluorophores with strong three-photon absorption (3PA) and bright emission that meets the requirements for efficient three-photon fluorescence microscopic (3PFM) bioimaging is still challenging. Herein, four bright fluorophores with aggregation-induced emission features are facilely synthesized, and their powders exhibit high quantum yields of up to 56.4%. The intramolecular engineering of luminogens endows (
)-2-(benzo
thiazol-2-yl)-3-(7-(diphenylamino)-9-ethyl-9
-carbazol-2-yl)acrylonitrile (DCBT) molecules with bright near-infrared emission and large 3PA cross sections of up to 1.57 × 10
cm
s
photon
at 1550 nm, which is boosted by 3.6-fold to 5.61 × 10
cm
s
photon
in DCBT dots benefiting from the extensive intermolecular interactions in molecular stacking. DCBT dots are successfully applied for 3PFM imaging of brain vasculature on mice with a removed or intact skull, providing images with high spatial resolution, and even small capillaries can be recognized below the skull. This study will inspire more insights for developing advanced multiphoton absorbing materials for biomedical applications.
Superb reliability and biocompatibility equip aggregation‐induced emission (AIE) dots with tremendous potential for fluorescence bioimaging. However, there is still a chronic lack of design ...instructions of excretable and bright AIE emitters. Here, a kind of PEGylated AIE (OTPA‐BBT) dots with strong absorption and extremely high second near‐infrared region (NIR‐II) PLQY of 13.6% is designed, and a long‐aliphatic‐chain design blueprint contributing to their excretion from an animal's body is proposed. Assisted by the OTPA‐BBT dots with bright fluorescence beyond 1100 nm and even 1500 nm (NIR‐IIb), large‐depth cerebral vasculature (beyond 600 µm) as well as real‐time blood flow are monitored through a thinned skull, and noninvasive NIR‐IIb imaging with rich high‐spatial‐frequency information gives a precise presentation of gastrointestinal tract in marmosets. Importantly, after intravenous or oral administration, the definite excretion of OTPA‐BBT dots from the body is demonstrated, which provides influential evidence of biosafety.
The long aliphatic chains of aggregation‐induced emission (AIE)‐gens are conducive to the excretion of AIE dots from an animal's body. The deep micro cerebrovasculature in marmosets is visualized through the thinned skull. Non‐invasive and high‐spatial‐frequency near‐infrared‐IIb imaging is utilized in non‐human primates. It is believed this work provides crucial ideas to advance the development of biosafe AIE dots and future nanomedicine.
The brightness of organic fluorescence materials determines their resolution and sensitivity in fluorescence display and detection. However, strategies to effectively enhance the brightness are still ...scarce. Conventional planar π-conjugated molecules display excellent photophysical properties as isolated species but suffer from aggregation-caused quenching effect when aggregated owing to the cofacial π-π interactions. In contrast, twisted molecules show high photoluminescence quantum yield (Φ
) in aggregate while at the cost of absorption due to the breakage in conjugation. Therefore, it is challenging to integrate the strong absorption and high solid-state Φ
, which are two main indicators of brightness, into one molecule. Herein, we propose a molecular design strategy to boost the brightness through the incorporation of planar blocks into twisted skeletons. As a proof-of-concept, twisted small-molecule TT3-
CB with larger π-conjugated dithieno3,2-
:2',3'-
thiophene unit displays superb brightness at the NIR-IIb (1500-1700 nm) than that of TT1-
CB and TT2-
CB with smaller thiophene and thienothiophene unit, respectively. Whole-body angiography using TT3-
CB nanoparticles presents an apparent vessel width of 0.29 mm. Improved NIR-IIb image resolution is achieved for femoral vessels with an apparent width of only 0.04 mm. High-magnification through-skull microscopic NIR-IIb imaging of cerebral vasculature gives an apparent width of ∼3.3 μm. Moreover, the deeply located internal organ such as bladder is identified with high clarity. The present molecular design philosophy embodies a platform for further development of
bioimaging.
Infections induced by Gram‐positive bacteria pose a great threat to public health. Antibiotic therapy, as the first chosen strategy against Gram‐positive bacteria, is inevitably associated with ...antibiotic resistance selection. Novel therapeutic strategies for the discrimination and inactivation of Gram‐positive bacteria are thus needed. Here, a specific type of aggregation‐induced emission luminogen (AIEgen) with near‐infrared fluorescence emission as a novel antibiotic‐free therapeutic strategy against Gram‐positive bacteria is proposed. With the combination of a positively charged group into a highly twisted architecture, self‐assembled AIEgens (AIE nanoparticles (NPs)) at a relatively low concentration (5 µm) exhibited specific binding and photothermal effect against living Gram‐positive bacteria both in vitro and in vivo. Moreover, toxicity assays demonstrated excellent biocompatibility of AIE NPs at this concentration. All these properties make the AIE NPs as a novel generation of theranostic platform for combating Gram‐positive bacteria and highlight their promising potential for in vivo tracing of such bacteria.
This study proposes a specific type of aggregation‐induced emission luminogen (AIEgen) with near‐infrared fluorescence emission as a novel antibiotic‐free theranostic platform for Gram‐positive bacteria. With the combination of a positively charged group into a highly twisted architecture, AIEgens, possessing excellent biocompatibility, exhibit specific binding and photothermal effect against living Gram‐positive bacteria.
Optical microscopy has enabled in vivo monitoring of brain structures and functions with high spatial resolution. However, the strong optical scattering in turbid brain tissue and skull impedes the ...observation of microvasculature and neuronal structures at a large depth. Herein, we proposed a strategy to overcome the influence induced by the high scattering effect of both skull and brain tissue via the combination of skull optical clearing (SOC) technique and three-photon fluorescence microscopy (3PM). The visible-NIR-II compatible skull optical clearing agents (VNSOCA) we applied reduced the skull scattering and water absorption in long wavelength by refractive index matching and H2O replacement to D2O respectively. 3PM with the excitation in the 1300-nm window reached 1.5 mm cerebrovascular imaging depth in cranial window assisted by a kind of bright aggregation-induced emission (AIE) nanoprobe we developed with a large three-photon absorption cross section. Combining the two advanced technologies together, we achieved so far the largest cerebrovascular imaging depth of 1.0 mm and neuronal imaging depth of> 700 µm through intact mouse skull. Dual-channel through-skull imaging of both brain vessels and neurons was also successfully realized, giving an opportunity of non-invasively monitoring the deep brain structures and functions at single-cell level simultaneously.
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•Skull optical clearing and three-photon microscopy were combined to reduce scattering interference.•Aggregation-induced emission nanoprobes with extremely large three-photon absorption section benefit deep imaging.•Through-skull three-photon mouse cerebrovascular imaging achieved the largest 1.0 mm imaging depth.
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