Development of imageable photothermal theranostics has attracted considerable attention for imaging guided photothermal therapy (PTT) with high tumor ablation accuracy. In this study, we strategically constructed a near-infrared (NIR) cyanine dye by introducing a rigid cyclohexenyl ring to the heptamethine chain to obtain a heptamethine dye CySCOOH with high fluorescence intensity and good stability. By covalent conjugation of CySCOOH onto human serum albumin (HSA), the as-prepared HSA@CySCOOH nanoplatform is highly efficient for NIR fluorescence/photoacoustic/thermal multimodality imaging and photothermal tumor ablation. The theranostic capability of HSA@CySCOOH was systematically evaluated both in vitro and in vivo. Most intriguingly, complete tumor elimination was achieved by intravenous injection of HSA@CySCOOH (CySCOOH, 1 mg/kg; 808 nm, 1.0 W/cm2 for 5 min) on 4T1 tumor-bearing mice, with no weight loss, noticeable toxicity, or tumor recurrence being observed. This as-prepared protein-based nanotheranostics exhibits high water dispersibility, no off target cytotoxicity, good biodegradability and biocompatibility, thus facilitating its clinical translation for cancer photothermal theranostics.
The imaging of sentinel lymph nodes (SLNs), the first defense against primary tumor metastasis, has been considered as an important strategy for noninvasive tracking tumor metastasis in clinics. In this study, we developed an imaging contrast system based on fluorescent dye-loaded mesoporous silica nanoparticles (MSNPs) that integrate near-infrared (NIR) fluorescent and photoacoustic (PA) imaging modalities for efficient SLN mapping. By balancing the ratio of dye and nanoparticles for simultaneous optimization of dual-modality imaging (NIR and PA), the dye encapsulated MSNP platform was set up to generate both a moderate NIR emission and PA signals simultaneously. Moreover, the underlying mechanisms of the relevance between optical and PA properties were discovered. Subsequently, dual-modality imaging was achieved to visualize tumor draining SLNs up to 2 weeks in a 4T1 tumor metastatic model. Obvious differences in uptake rate and contrast between metastatic and normal SLNs were observed both in vivo and ex vivo. Based on all these imaging data, it was demonstrated that the dye-loaded MSNPs allow detection of regional lymph nodes in vivo with time-domain NIR fluorescent and PA imaging methods efficiently.
Photoacoustic imaging (PA) has emerged as a novel and noninvasive imaging modality owing to its high spatial resolution and high soft tissue contrast. Herein, we loaded a near-infrared (NIR) fluorescence dye (CySCOOH) onto the surface of PEGylated graphene oxide (GO) via π-π stacking to increase the NIR absorbance of GO. The PA imaging proved that PEGylated GO-CysCOOH (GO-PEG-CysCOOH) significantly enhances the PA signal in the tumor site compared with free GO-PEG. We then utilized the strong optical absorbance of GO-PEG-CySCOOH in the NIR region for in vivo photothermal therapy, achieving efficient tumor ablation after intravenous injection of GO-PEG-CySCOOH and low-power laser irradiation on the tumor. Our results indicate that this graphene-based nanocomposite can be developed as a promising contrast agent for PA imaging and a thermal agent for imaging guided photothermal therapy.
A novel ratiometric and colorimetric probeH2S-CRfor the quantitative detection of H2S was designed and synthesized based on a H2S induced Michael addition–cyclization cascade reaction and the FRET modulated fluorescence off-on response.
Integrins have an important impact on the regulation of normal and tumor cell migration and survival, especially the integrin αvβ3 and its role in angiogenesis and tumor metastasis. Owing to the role of integrins, non-invasive imaging of αvβ3 expression in diseased tissue will be of great benefit in directing adjuvant therapy for cancer patients. To this end, RGD peptide based probes for optical imaging have emerged as a real-time, sensitive, and noninvasive approach for visualization, localization, and measurement of cancer in vivo. With the advantages of optical imaging such as sensitivity, cost effectiveness, and non-invasion, the past decades have witnessed the rapid development of integrin- targeted optical probes and its wide applications in cancer research. In this review, we present and introduce numerous approaches by the term "RGD motif based optical imaging probes" with respect to their probe design strategies and applications. Additionally, a variety of labels such as QDs, UCLs and near-infrared fluorochrome used in these optical imaging probes are also discussed.
In this study, agglomerated nanocrystalline ZrO2--Y2O3 powder was calcinated from 900 to 1300 °C for 2 h. The calcinated nanopowder was used as feedstock and deposited by air plasma spraying on a NiCoCr bond coat applied to a nickel substrate via low pressure plasma spraying. For comparison, conventional ZrO2-Y2O3 topcoats were also produced. Nanostructured and conventional thermal barrier coatings were calcinated from 1050 to 1250 °C for 2-20 h. Experimental results indicate that monoclinic tetragonal phases in the agglomerated nanopowder were transformed into cubic phase after calcination. The cubic phase content increased with increasing calcination temperature. High temperature calcination can make the yttria segregated at grain boundaries dissolve in zirconia. Different from the phase constituent of the as-sprayed conventional TBC, which consisted of diffusionless transformed tetragonal, the as-sprayed nanostructured TBC consisted of cubic phase containing high yttria. No phase transformations were observed in either TBC after calcination.
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