Supramolecular Polymeric Fluorescent Nanoparticles Based on Quadruple Hydrogen Bonds

A facile approach for the preparation of supramolecular polymer‐based fluorescent nanoparticles (FNPs) is reported. FNPs with homogeneous shape and size distribution are fabricated from low‐molecular‐weight molecules, and thus, different compositional constituents can be efficiently incorporated via copolymerization. The emission color of the FNPs covers a wide region from blue to near infrared and can be easily tuned using efficient excitation energy transfer. The photoswitchable fluorescent nanoparticles with high on–off fluorescence contrast are also simply prepared by copolymerization of monomers containing a fluorophore and a photochromic unit. Our FNPs are successfully applied in living cell imaging and as fluorescent inks.     

Synthesis,Characterization, and Application of Antibody Functionalized Fluorescent Silica Nanoparticles

Fluorescent silica nanoparticles (FSNs) are prepared by incorporating dye into a mesoporous silica nanoparticle (MSN) synthesis procedure. FSNs containing sulforhodamine B, hydrophobically modified sulforhodamine B, and Cascade Blue hydrazide are made. The MSN‐based FSNs do not leach dye under simulated physiological conditions and have strong, stable fluorescence. FSNs prepared with sulforhodamine B are compared to FSNs prepared with hydrophobically modified sulforhodamine B. The data indicate that FSNs prepared with sulforhodamine B are equally as stable but twice as fluorescent as particles made with hydrophobically modified sulforhodamine B. The fluorescence of a FSN prepared with sulforhodamine B is 10 times more intense than the fluorescence of a 4.5 nm core–shell CdSe/ZnS quantum dot. For diagnostic applications, a method to selectively and covalently bind antibodies to the surface of the FSNs is devised. FSNs that are functionalized with antibodies specific for Neisseria gonorrhoeae specifically bind to Neisseria gonorrhoeae in flow cytometry experiments, thus demonstrating the functionality of the attached antibodies and the potential of MSN‐based FSNs to be used in diagnostic applications.     

Generic Method of Preparing Multifunctional Fluorescent Nanoparticles Using Flash NanoPrecipitation

There is increased demand for nanoparticles with a high fluorescence yield that have the desired excitation wavelength, surface functionalization, and particle size to act as biological probes. Here, a simple, rapid, and robust method, Flash NanoPrecipitation (FNP), to produce such fluorescent nanoparticles is described. This process involves encapsulation of a hydrophobic fluorophore with an amphiphilic biocompatible diblock copolymer in a kinetically frozen state. FNP is used to produce nanoparticles ranging from 30 to 800 nm with fluorescence emission peaks ranging from, but not limited to, 370 nm to 720 nm. Such fluorescent nanoparticles remain stable in aqueous solutions, and, in contrast to soluble dyes, show no photobleaching. Fluorophores and drugs are incorporated into a single nanoparticle, allowing for simultaneous drug delivery and biological imaging. In addition, functionalization of nanoparticle surfaces with disease‐specific ligands permits precise cell targeting. These features make FNP‐produced fluorescent nanoparticles highly desirable for various biological applications.     

In Vivo Photoacoustic Imaging of Livers Using Biodegradable Hyaluronic Acid‐Conjugated Silica Nanoparticles

The diagnosis of liver diseases is generally carried out via ultrasound imaging, computed tomography, and magnetic resonance imaging. The emerging photoacoustic imaging is an attractive alternative to diagnose even early stage of liver diseases providing high‐resolution anatomical and functional information in deep tissue noninvasively. However, the liver has insufficient photoacoustic contrast due to low optical absorbance in the near‐infrared windows. Here, a new hyaluronate–silica nanoparticle (HA–SiNP) conjugate for liver‐specific delivery and imaging for the diagnosis of liver diseases is developed. The HA–SiNP conjugates show high liver‐specific targeting efficiency, strong optical absorbance near‐infrared windows, excellent biocompatibility, and biodegradability. The liver‐specific targeting efficiency is verified by in vitro cellular uptake test, and in vivo and ex vivo photoacoustic imaging. In vivo photoacoustic imaging shows that photoacoustic amplitude in the liver injected with HA–SiNP conjugates is 4.4 times higher than that of the liver injected with SiNP. The biocompatibility and biodegradability of HA–SiNP conjugates are verified by cell viability test, optical spectrum analysis of urine, and inductively coupled plasma‐mass spectroscopy (ICP‐MS) analysis. Taken together, HA–SiNP conjugates may be developed as a promising liver targeted photoacoustic imaging contrast agent and liver‐targeted drug delivery agent.     

Ultrabright Fluorescent Silica Mesoporous Silica Nanoparticles: Control of Particle Size and Dye Loading

The synthesis of ultrabright fluorescent mesoporous silica nanoparticles (UFSNPs) of various sizes loaded with different amounts of fluorescent dye (Rhodamine 6G) is reported here. The dye is physically entrapped inside the nanochannels of the silica matrix created during templated sol–gel self assembly. Due to the specific nanoenvironment, the fluorescence of the encapsulated dye molecules remains unquenched up to very high concentrations, which results in relatively high fluorescence. The particle size (ranging from 20–50 nm) and dye loading (0.8–9.3 mg dye per g particles) are controlled by the timing of the synthesis and the concentration of several organotriethoxysilanes, which are coprecursors of silica. The quantum yields of the encapsulated dye range from 0.65 to 1.0. The relative brightness of a single particle is equivalent to the fluorescence of 30–770 free nondimerized R6G dye molecules in water, or to that of 1.5–39 CdSe/ZnS quantum dots. Despite the presence of some hydrophobic groups on the particles' surfaces, colloidal suspensions of the particles are relatively stable (as monitored for 120 days).     

Fluorescent Conjugated Polyelectrolytes for Bioimaging

This Feature Article summarizes the recent advances of water‐soluble fluorescent conjugated polyelectrolytes (CPEs) in bioimaging. Apart from a brief overview of traditional linear CPEs, a special emphasis is placed on CPEs that can self‐assemble into or are born with three‐dimensional nano‐architectures, including grafted CPEs, hyperbranched CPEs, and polyhedral oligomeric silsesquioxanes(POSS)‐based CPE derivatives. These CPEs naturally form nanoparticles with sizes ranging from 3 to 100 nm in aqueous media, and possess reactive functional groups for bioconjugation or complexation with desired biorecognition elements. The tunable size, low cytotoxicity, good photostability, and ease of surface modification ultimately enable these CPEs with wide applications in in vitro intracellular protein sensing, cell detection, in vivo cell imaging and drug tracking. Moreover, traditional linear CPEs can be transformed into uniform nanoparticles by complexation with oppositely charged biomolecules to allow for cell detection and in situ drug release monitoring. The work featured herein not only reveals the important molecular design principles of CPEs for different imaging tasks, but also highlights the promising directions for the further development of CPE‐based imaging materials.     

Tetrahydro[5]helicene‐Based Nanoparticles for Structure‐Dependent Cell Fluorescent Imaging

Four new fluorescent dyes containing tetrahydro[5]helicene moiety characterized by three‐primary emission colors (blue‐green‐red) are designed and synthesized, and their structures are characterized by NMR, MS, and single crystal X‐ray crystallography. Organic nanoparticles based on the fluorescent dyes are then prepared by re‐precipitation method, and their photophysical properties are investigated. These nanoparticles retain the strong emissions of the organic dyes, and multicolor nanoparticles were also prepared by simply tuning the ratios of the three‐primary colors dyes. These organic nanoparticles exhibit low cytotoxicity, good photostability, and high quantum yields. Moreover, the nanoparticles can also be applied in the cell fluorescence imaging. Especially, it is interestingly found that the stained regions of these nanoparticles from membrane to cytoplasm for HeLa cells show obvious structure‐dependent properties. This strategy provides a new perspective to fluorescence probe by molecular design for specific location imaging of living cells.     

Formulation of Superparamagnetic Iron Oxides by Nanoparticles of Biodegradable Polymers for Magnetic Resonance Imaging

A system of poly(lactide‐co‐glycolide)‐methoxy poly(ethylene glycol) (PLGA‐mPEG) nanoparticles is developed to formulate superparamagnetic iron oxides (IOs) for magnetic resonance imaging (MRI). This system improves the imaging effects, increases the half‐life of the IOs in circulation, and reduces their side effects. The IO‐loaded PLGA‐mPEG nanoparticles were prepared by a modified water‐in‐oil‐in‐water double‐emulsion technique. Their physicochemical and superparamagnetic properties were characterized by various techniques. In vitro IO release kinetics from the nanoparticles and stability of the IO‐loaded polymeric nanoparticles were also investigated. In vitro and ex vivo MRI of the IOs formulated in the PLGA‐mPEG nanoparticles show that the saturation magnetization and the r₂, r₂* relaxivities are enhanced, and the contrast effects are improved in comparison with commercial IOs (Resovist). It is proven that the enhanced superparamagnetic properties are caused by the polymeric nanoparticle formulation but not by the polymeric material itself. Moreover, the PLGA‐mPEG nanoparticle formulation achieves 36.9 and 35.6 % less cytotoxicity in comparison with the IOs (Resovist) after 48 h incubation at the same 20 and 50 μg mL^–1 Fe concentration, respectively. This research implies that formulation of IOs by nanoparticles of PLGA‐mPEG copolymer or other biodegradable polymers could be promising for more effective and sustainable MRI with reduced side effects, which, with targeting probes conjugated to the nanoparticle surface, can be further used to promote cellular and molecular MRI.     

InGaP@ZnS‐Enriched Chitosan Nanoparticles: A Versatile Fluorescent Probe for Deep‐Tissue Imaging

InGaP QDs overcoated with several monolayers of ZnS are covalently bound to chitosan to address the challenges of developing highly biologically stable and fluorescent nanoparticle probes for deep‐tissue imaging. Transmission electron microscopy images reveal that the average diameter of these luminescent nanoparticles is approximately 29 nm, and they contain multiple InGaP@ZnS QDs that have an average diameter between 4 and 5 nm. These new InGaP@ZnS–chitosan nanoparticles emit near the near IR region at 670 nm and are able to penetrate three times deeper into tissue (e.g., even through a mouse skull) while revealing a higher uptake efficiency into PC12 cells with a robust signal. Additionally, a cell viability assay demonstrates that these new fluorescent nanoparticles have good biocompatibility and stability with PC12 cells and neural cells. As a result, these near‐IR‐emitting nanoparticles can be used for real‐time and deep‐tissue examination of diverse specimens, such as lymphatic organs, kidneys, hearts, and brains, while leaving the tissue intact.     

荧光磁粉探伤自动化检测系统

介绍了如何实现荧光磁粉探伤自动化检测系统。该系统在荧光磁粉探伤原理的基础上,以计算机作为中心控制系统,控制磁粉探伤机和步进电机,同时结合图像处理和机器视觉技术,对工件的金属壳体进行尺寸和缺陷检测。     

Designing Squaraine Dyes with Bright Deep-Red Aggregation-Induced Emission for Specific and Ratiometric Fluorescent Detection of Hypochlorite

Development of ratiometric fluorescent hypochlorite probes with strong long wavelength fluorescence in aqueous medium, high resistance to photobleaching, high sensitivity and selectivity, and low biological toxicity remains a challenge. In this work, a molecular design strategy is proposed that can transform the traditional squaraine dyes (SQs) with aggregation-caused quenching character into aggregation-induced emission (AIE)-active luminogens by functionalizing the end-groups with tetraphenylethylene units and further introducing hydrophilic sulfonate group as the side chains. The resulting TPE-SQ5 not only emits strong deep-red fluorescence with a high quantum yield of 11.0% and high photostability, but more encouragingly can serve as a ratiometric fluorescent hypochlorite probe with high selectivity and sensitivity (detection limit: 5.6 nm ), which indeed is the first report for SQs. The detailed sensing mechanism study demonstrates that the oxindole product with sulfonate substitution is responsible for the ratiometric fluorescent response. Furthermore, TPE-SQ5 nanoparticles with high biocompatibility and low cytotoxicity are successfully used for ratiometrically imaging exogenous and endogenous hypochlorite in living cells.     

荧光寿命的锁相检测技术研究

针对光纤荧光温度传感器中影响系统精用参考信号、用正弦信号来调制激励光源的锁相技术(PLD-AMSR)对荧光光纤温度传感器的荧光寿命进行检测,推导出测量荧光寿命的数学模型.该方法对激励光泄露有抑制作用,使测量精度有了显著提高.实验表明,该方法是有效的,达到了系统要求.     

Colorectal Cancer Diagnosis Using Enzyme‐Sensitive Ratiometric Fluorescence Dye and Antibody–Quantum Dot Conjugates for Multiplexed Detection

A rapid and accurate molecular fluorescence imaging technique will greatly reduce cancer mortality by overcoming the detection limit of the naked eye in colonoscopy. Two imaging probes are reported that can be co‐used for colonoscopic diagnosis: a fluorescent molecular probe, cresyl violet–glutamic acid derivative, that ratiometrically switches between two fluorescent colors in response to the enzyme activity of λ‐glutamyltranspeptidase and an antibody quantum dot probe that is a conjugate of biocompatible AgInS₂ quantum dot with matrix metalloproteinase 14 antibodies. Validity of the probes is confirmed using human colon cancer cell lines, ex vivo mouse model tissues, and patient tumor colon tissues in which the tumor lesions are well‐visualized in less than five minutes. Co‐application of the two probes onto fresh colon tissues affords accurate visualization of carcinomas and also hyperplasia and adenoma regions. Fresh human colon adenoma tissues are also valuated, where the two probes show complementary diagnoses of cancer. Two‐photon microscopy shows the time‐dependent depth profiles of the two probes. Both rapidly permeate and populate most at 10–20 µm from the surface. Extensive toxicity studies are performed for the two probes at cellular level and also at the organ level using a small animal model.     

超分辨成像中荧光分子定位算法性能比较

超分辨成像已成为活细胞结构和功能成像的关键工具,荧光分子定位是超分辨成像过程中不可缺少的步骤。从超分辨成像角度研究各种荧光分子定位算法性能具有重要的意义。选择5种典型的荧光分子定位算法:质心法、广义质心法、高斯拟合、解线性方程组和极大似然法,以定位精度和定位时间来评价所选择算法的性能。结果表明,1)高斯拟合、极大似然法和广义质心法能高精度对荧光分子定位,不受荧光分子所在子区域提取的影响;2)质心法和解线性方程组法能应用于图像在线分析,但定位精度较低,受子区域提取影响较大;3)当两个荧光分子位于一个衍射斑时,采用这5种算法的定位精度都会急剧下降。     

Thermoresponsive Semiconducting Polymer Nanoparticles for Contrast‐Enhanced Photoacoustic Imaging

Photoacoustic (PA) agents with biomarker‐activated signals are developed to enhance the signal‐to‐background ratios (SBRs) for in vivo imaging; however, their SBRs still heavily rely on the concentration difference of biomarkers between diseased and normal tissues. By contrast, external stimuli can provide a remote way to noninvasively control the signal generation from the PA agents and in turn enhance SBR, which are less exploited. This study reports the development of thermoresponsive semiconducting polymer brush with poly(N,N‐dimethylacrylamide)‐r‐(hydroxypropyl acrylate) (PDMA‐r‐HPA) grafts for contrast‐enhanced in vivo imaging. Such a polymer is amphiphilic and can self‐assemble into the nanoparticle (termed as SPNph1) in an aqueous medium, and has lower critical solution temperatures (LCSTs) at 48 °C. Thus, SPNph1 not only has higher photothermal conversion efficiency than the control polymer without PDMA‐r‐HPA grafts, but also can undergo phase separation to form large nanoparticles, leading to enhanced PA signals above LCST. The thermoresponsive PA property of SPNph1 enables in situ remote manipulation of PA signals by photoirradiation to further enhance the tumor SBR. Thus, this study introduces a new generation of organic PA agents with thermoresponsive signal for high‐contrast in vivo imaging.     

医疗内窥镜影像系统的设计与实现

设计并实现了消化内镜影像系统的常用功能,并增加了病变图像的二次采集,典型病例库的维护以及“所见即所得”的报告生成方式,提高了诊断效率。并对系统进行了全面的测试,保证了系统的稳定性和功能完备性。     

New Generation of Multifunctional Nanoparticles for Cancer Imaging and Therapy

Advances in nanotechnology have contributed to the development of novel nanoparticles that enable the tumor‐specific delivery of imaging probes and therapeutic agents in cancer imaging and therapy. Nanobiotechnology combines nanotechnology with molecular imaging, which has led to the generation of new multifunctional nanoparticles for cancer imaging and therapy. Multifunctional nanoparticles hold great promise for the future of cancer treatment because they can detect the early onset of cancer in each individual patient and deliver suitable therapeutic agents to enhance therapeutic efficacy. The combination of tumor‐targeted imaging and therapy in an all‐in‐one system provides a useful multimodal approach in the battle against cancer. Novel multifunctional nanoparticles thus offer a new avenue in the application of personalized medicine in the near future. Herein, new trends and the significance of novel multifunctional nanoparticles in cancer imaging and therapy are reviewed.

     

基于荧光光谱法的皮肤胆固醇快速无创检测技术

皮肤胆固醇含量可以作为评价动脉粥样硬化的重要指标之一,现有的皮肤胆固醇含量检测主要基于实验室活检进行,缺少快速无创的检测技术和装备。针对以皮肤胆固醇含量为评价指标的动脉粥样硬化的早期快速筛查需求,本文提出了基于荧光光谱法的皮肤胆固醇快速无创检测方法,研发了一种皮肤胆固醇无创检测系统。为了提高测量的准确性和稳定性,该系统对温度引起的检测试剂荧光效率的波动进行了修正。本文结合气相色谱法对测量结果的准确性进行了验证,并通过检测正常人群和动脉粥样硬化高风险人群的皮肤胆固醇含量,明确了该系统的临床应用价值。本文的研究结果表明,462~520 nm波段内的平均荧光强度与温度的相关系数为-0.995(p<0.0001),可据此建立温度校准曲线对由温度差异引起的荧光波动进行修正。校正后,系统测量的皮肤胆固醇含量与气相色谱测量值的相关性显著,相关系数为0.905(p<0.0001)。在动脉粥样硬化高风险人群的筛查实验中,动脉粥样硬化高风险人群和正常人群的皮肤胆固醇检测结果具有显著差异(P=0.0004)。与现有技术相比,基于荧光光谱法的皮肤胆固醇检测技术具有测量快速无创等优势,为大规模开展动脉粥样硬化的早期风险筛查提供了先进技术手段。