A"donor–acceptor"structured semiconductor polymer for near infrared fluorescence imaging guided photodynamic therapy

Near infrared(NIR)fluorescence imaging guided photodynamic therapy(PDT)is a technique which has been developed in many clinical trials due to its advantage of real-time optical monitoring,specific spatiotemporal selectivity,and minimal invasiveness.For this,photosensitizers with NIR fluorescence emission and high^(1)O_(2)generation quantum yield are highly desirable.Herein,we designed and synthesized a"donor-acceptor"(D-A)structured semiconductor polymer(SP),which was then wrapped with an amphiphilic compound(Pluronic■F127)to prepare water-soluble nanoparticles(F-SP NPs).The obtained F-SP NPs exhibit good water solubility,excellent particle size stability,strong absorbance at deep red region,and strong NIR fluorescent emission characteristics.The maximal mass extinction coe±cient and fluorescence quantum yield of these F-SPs were calculated to be 21.7 L/(g·cm)and 6.5%,respectively.Moreover,the^(1)O_(2)quantum yield of 89%for F-SP NPs has been achieved under 635 nm laser irradiation,which is higher than Methylene Blue,Ce6,and PpIX.The outstanding properties of these F-SP NPs originate from their unique D-A molecular characteristic.This work should help guide the design of novel semiconductor polymer for NIR fluorescent imaging guided PDT applications.

Single ultrasmall Mn2＋-doped NaNdF4 nanocrystals as multimodal nanoprobes for magnetic resonance and second near-infrared fluorescence imaging

Multimodal imaging probes have attracted wide attention and have potential to diagnose diseases accurately because of the complementary advantages of multiple imaging modalities. However, intractable issues remain with regard to their complicated multi-step fabrication for hybrid nanostructure and interference of different modal imaging. In the present stud we present, for the first time, T1 and T2-weighted magnetic resonance imaging （MRI） of ultrasmaU Mn2＋-doped NaNdF4 nanocrystals （NCs）, which can also be used simultaneously for second near infrared （NIR-U） fluorescence and computed tomography （CT） imaging, thus enabling high-performance multimodal MRI/NIR-II/CT imaging of single NaNdF4：Mn NCs. The NaNdF4：Mn was demonstrated as a nanoprobe for in vitro and in vivo multimodal MRI and NIR-II fluorescence imaging of human mesenchymal stem cells. The results provide a new strategy to simplify the nanostructure and preparation of probes, based on the features of NaNdF4：Mn NCs, which offer highly efficient multimodal MRI/NIR-II/CT imaging.

Rationally designed meso-benzimidazole-pyronin with emission wavelength beyond 700 nm enabling in vivo visualization of acute-liver-injury-induced peroxynitrite

Fluorescent dyes with fluorescence emission above 700 nm are favorable for bio-imaging due to the higher tissue transparency and lower background fluorescence. In this study, we present a mesobenzimidazole-pyronin platform(Si BMs) with fluorescence emission maxima above 700 nm, which possess good cell permeability, photostability, and lysosomal localization. The great photophysical properties of the Si BMs encouraged us to further exploit their application toward bio-imaging. We synthesized the reduced ‘dihydro’ derivative HSi BM3 for sensing ONOO^(-), with high selectivity and sensitivity and a fast fluorescence “off-on” response(within 2 s). Then, we confirmed the potential of HSi BM3 for visualizing exogenous and endogenous ONOO-in cells and mice. More importantly, HSi BM3 was successfully employed for visualizing acute-liver-injury-induced peroxynitrite.

Folate-targeted co-delivery polymersomes for efficient photo-chemo-antiangiogenic therapy against breast cancer and in vivo evaluation via OCTA/NIRF dual-modal imaging

Intelligent nanoplatform that combines multimodal imaging and therapeutic effects holds great promise for precise and efficient cancer therapy.Herein,folate-targeted polymersomes with stimuli-responsiveness were fabricated and evaluated by near-infrared fluorescence(NIRF)and optical coherence tomography angiography(OCTA)dual-imaging for photo-chemo-antiangiogenic therapy against cancer.The folate-targeted polymersomes(FA-MIT-SIPS)not only integrated ammonium bicarbonate(ABC)and mitoxantrone(MIT)into their hydrophilic cavity but also encapsulated indocyanine green(ICG)and sorafenib(SOR)within their hydrophobic layer.NIRF imaging demonstrated that FA-MIT-SIPS effectively accumulated and retained in the tumors.Upon 808 nm laser irradiation,the ICG produced hyperthermia and reactive oxygen species(ROS)for efficient photothermal and photodynamic therapy.In addition,the decomposition of ABC in responsive to acidic tumor environment and ICG-induced hyperthermia accelerated drug release.The released MIT accumulated in nucleus to inhibit DNA synthesis,while the released SOR destructed tumor vascularization.Notably,OCTA imaging was applied to observe the tumor blood flow upon the combination therapy,demonstrating that FA-MIT-SIPS obviously decreased the vessels area density.Moreover,the synergistic photo-chemo-antiangiogenic therapy of FA-MIT-SIPS achieved excellent antitumor effect with 40%of the 4T1 tumor-bearing mice being completely cured without recurrence.The multifunctional polymersomes provide a promising dual-modal imaging-evaluated synergistic strategy for tumor therapy.

Effect of yttrium oxide addition on absorption and emission properties of bismuth-doped silicate glasses

Y/Bi co-doped silicate glasses were prepared,and the effects of Y 2 O 3 on the absorption and emission properties were investigated by spectrum measurement.It was found that the absorption intensity in visible region decreases with increase of Y 3＋ concentration in（70-x）SiO 2 xY 2 O 3-30CaO-1.5Bi 2 O 3（x=0 mol.%,1 mol.%,3 mol.%,5 mol.%,7 mol.%） glasses.The emissions centered at 410,630,1200 and 1290 nm were observed under 280,470,514 and 808 nm excitation,respectively.The emission intensity had the similar change tendency in the visible and near infrared region.We also discussed the actual role of Y 3＋ ions playing in the visible and near infrared emissions of the silicate glasses.