We experimentally demonstrate an ultra‐sensitive immunoassay biosensor using diatom biosilica with self‐assembled plasmonic nanoparticles. As the nature‐created photonic crystal structures, diatoms have been adopted to enhance surface plasmon resonances of metal nanoparticles on the surfaces of diatom frustules and to increase the sensitivity of surface‐enhanced Raman scattering (SERS). In this study, a sandwich SERS immunoassay is developed based on the hybrid plasmonic‐biosilica nanostructured materials that are functionalized with goat anti‐mouse IgG. Our experimental results show that diatom frustules improve the detection limit of mouse IgG to 10 pg/mL, which is ?100× better than conventional colloidal SERS sensors on flat glass.
Ultra‐sensitive immunoassay biosensor using diatom biosilica with self‐assembled plasmonic nanoparticles. 相似文献
CdTe quantum dots (QDs) are widely used in bio‐applications due to their size and highly efficient optical properties. However internalization mechanisms thereof for the variety of freshly extracted, not cultivated human cells and their specific molecular interactions remains an open topic for discussion. In this study, we assess the internalization mechanism of CdTe quantum dots (3.3 nm) capped with thioglycolic acid using non cultivated oral epithelial cells obtained from healthy donors. Naked gold nanoparticles (40 nm) were successfully used as nanosensors for surface‐enhanced Raman spectroscopy to efficiently identify characteristic Raman peaks, providing new evidence indicating that the first interactions of these QDs with epithelial cells occurred preferentially with aromatic rings and amine groups of amino acid residues and glycans from trans‐membrane proteins and cytoskeleton. Using an integrative combination of advanced imaging techniques, including ultra‐high resolution SEM, high resolution STEM coupled with EDX spectroscopy together with the results obtained by Raman spectroscopy, it was determined that thioglycolic acid capped CdTe QDs are efficiently internalized into freshly extracted oral epithelial cells only by facilitated diffusion, distributed into cytoplasm and even within the cell nucleus in three minutes.
A label‐free interferometric transducer showing a theoretical detection limit for homogeneous sensing of 5 × 10–8 RIU, being equivalent to a protein mass coverage resolution of 2.8 fg mm–2, is used to develop a high sensitive biosensor for protein detection. The extreme sensitivity of this transducer combined with a selective bioreceptor layer enables the direct evaluation of the human growth hormone (hGH) in undiluted urine matrix in the 10 pg mL–1 range.
We report the development of a depth‐sensitive Raman spectroscopy system using the configuration of cone–shell excitation and cone detection. The system uses a 785 nm diode laser and three identical axicons for Raman excitation of the target sample in the form of a hollow conic section. The Raman scattered light from the sample, passed through the same (but solid) conic section, is collected for detection. Apart from its ability of probing larger depths (? few mm), an important attraction of the system is that the probing depths can be varied by simply varying the separation between axicons in the excitation arm. Furthermore, no adjustment is required in the sample arm, which is a significant advantage for noncontact, depth‐sensitive measurement. Evaluation of the performance of the developed setup on nonbiological phantom and biological tissue sample demonstrated its ability to recover Raman spectra of layers located at depths of ?2–3 mm beneath the surface.
Infrared attenuated total reflection spectroscopy is an emerging label‐free method for analyzing the degree of damage in cartilage samples. In the present study, sheep menisci have been characterized after meniscectomy via the variances of relevant biomolecules at the incision surface. Further details can be found in the article by Angela I. López‐Lorente et al. ( e201800429 ).
A catheter‐based OCT system is used in intubated mechanically‐ventilated critical care patients for the in vivo detection of endotracheal tube biofilm formation, which has been linked to ventilator‐associated pneumonia and death. The combination of attenuation coefficient and structural imaging enables longitudinal monitoring of biofilm growth and differentiation from mucus. In contrast to conventional diagnostic procedures, this approach provides effective real‐time bed‐side detection of biofilms. Further details can be found in the article by Roshan Dsouza, Darold R. Spillman Jr., Ronit Barkalifa, et al. ( e201800307 ).
Over the past years it had been demonstrated that multimodal imaging combining the nonlinear modalities coherent anti‐Stokes Raman scattering (CARS), two‐photon excited auto‐fluorescence (TPEF) and second harmonic generation (SHG) show a great potential for tissue diagnosis and tumor identification. To extend the applicability of this multimodal imaging approach for in‐vivo tissue screening of difficult to access body regions the development of suitable fiber optic probes is required. Here we report about a novel CARS imaging fiber probe consisting of 10,000 coherent light guiding elements preserving the spatial relationship between the entrance and the output of the fiber. Therefore the scanning procedure can be shifted from the distal to the proximal end of the fiber probe and no moving parts or driving current are required to realize in‐vivo CARS endoscopy.
Back scattered CARS image of rabbit aorta with plaques (white) using a laser scanning microscope and an imaging fiber. 相似文献
The nuclei of epithelial cells in stratified squamous epithelia have been reported to be either low scattering or high scattering. Using micro‐optical coherence tomography, we demonstrate that the nuclei are ‘low scattering’ in the core; those previously reported ‘high‐scattering’ signals are likely from the nucleocytoplasmic boundary. Further details can be found in the article by Si Chen, Xinyu Liu, Nanshuo Wang, et al. ( e201900073 ).
This schematic depicts the classification of multiphoton images with different degrees of HCC differentiation using the VGG‐16 neural network. The convolution layer is further trained based on the original weights. The weights of the fully connected layers are initialized as a random number and the training is restarted to improve its classification accuracy. Further details can be found in the article by Hongxin Lin, Chao Wei, Guangxing Wang, et al. ( e201800435 ).
The forward elastic‐light‐scattering pattern of a bacterial colony reflects its morphological characteristics. Three bacteria genera whose colonies having convex, crateriform, or irregular elevation were investigated to study the correlation between the morphology and the scattering pattern of the colony. The difference in the colony elevation produced distinct shapes of light diffraction in the scattering pattern, resulting circular diffraction rings or scattered light. Further details can be found in the article by Iyll‐Joon Doh, Jennifer Sturgis, Diana V. Sarria Zuniga, et al. ( e201900149 ).
Endovenous laser ablation (EVLA) has frequently been used to treat varicose veins for 20 years. In spite of 90?95% occlusion rates, clinical complications such as burn and ecchymosis still occur due to excessive thermal injury to perivenous tissue. In the current study, a glass‐capped diffusing applicator is designed to validate the feasibility of EVLA as an effective therapeutic device by applying circumferential light distribution. The proposed device is evaluated with a flat fiber as a reference in terms of temperature elevation, fiber degradation, and degree of coagulative necrosis after 532 nm‐assisted EVLA at 100 J/cm. The diffusing fiber generates a 40% lower maximum temperature with a 90% lower transient temperature change in blood, compared to the flat fiber. Due to low irradiance (13.5 kW/cm2) and wide light distribution, the diffuser tip experiences no significant thermal degradation while severe carbonization occurs at the flat fiber tip. Ex vivo tissue tests verify that the diffusing fiber induces circumferential and consistent tissue denaturation to the vein wall (107.8 ± 7.8 µm) along with 19% vessel shrinkage. The proposed glass‐capped diffusing applicator can be a feasible therapeutic device for EVLA with minimal complications by entailing low maximum temperatures and uniform tissue denaturation in the venous tissue.
Thrombosis monitoring in vivo in small animals is of great value in basic research. The aim of this study is to utilize OCT to monitor thrombosis progression in femoral vein of mice from various measurement criteria, and to validate its use in evaluation the efficacy of the antithrombotic drug. The proved capability of obtaining thrombodynamics information in mice model provide valuable use in preclinical studies for anti‐thrombotic drugs development research. Further details can be found in the article by Yao Yu, Menghan Yu, Jian Liu, et al. ( e201900105 ).
A wearable device based on fiber optic biosensor for high‐precision radial pulse wave monitoring and diagnosis is proposed and demonstrated in this article. Owing to the high sensitivity of the tiny fiber tip with aluminum diaphragm assembled in the sportswristband, weak acoustic signal induced by arterial pulse can be high‐fidelity recovered and then quantitatively analyzed for clinical diagnosis, which is promising in early cardiovascular diseases indicating. Further details can be found in the article by Jingyi Wang, Kewei Liu, Qizhen Sun, et al. ( e201900084 ).
Optical tissue clearing is a method allowing post‐mortem deep imaging of organs in three dimensions. By optimizing the CUBIC clearing protocol, the authors provide rapid and simple approach to clear the entire adult rat organism within as little as four days, which is accompanied by the variety of its staining and imaging techniques. The image was captured with polarizers and demonstrates transparent rodent heart with thread‐like crystals of clearing reagent. Further details can be found in the article by Pawe? Matryba et al. ( e201700248 ).
Dysfunctions in tissue metabolism can be detected at early stages by oxygen partial pressure (pO2) measurement. The measurement of emission lifetimes offers very promising and non‐invasive approach to estimate pO2in vivo. This study compares two extensively used oxygen sensors and assesses their in vivo oxygen sensitivity and phototoxic effect. Luminescence lifetime of Ru‐polypyridyl complex and of Pd‐porphyrin is measured in the Chick's Chorioallantoic Membrane (CAM) model with a dedicated optical fiber‐based, time‐resolved spectrometer. The Pd‐porphyrin luminescence lifetimes measured in the CAM model exposed to different pO2 levels are longer and have a broader dynamic range (10–100 μs) than those of Ru‐polypyridyl complex (0.6–1 μs). The combined statistical analysis based on an estimate of the kurtosis and skewness, bootstrapping method and routine normality tests is performed. The indicators of the averages and signal to noise ratio stability are also calculated. The combination of several data processing allows selection of the better sensor for a given application. In particular, it is found that the advantage of Ru‐polypyridyl complex over Pd‐porphyrin is two‐fold: i) Ru‐polypyridyl complex datasets have consistently better statistical characteristics, ii) Ru‐polypyridyl exhibits lower cytotoxicity.
The speed and efficiency of quantum cascade laser‐based mid‐infrared microspectroscopy are demonstrated using two different model organisms as examples. For the slowly moving Amoeba proteus, a quantum cascade laser is tuned over the wavelength range of 7.6 µm to 8.6 µm (wavenumbers 1320 cm–1 and 1160 cm–1, respectively). The recording of a hyperspectral image takes 11.3 s whereby an average signal‐to‐noise ratio of 29 is achieved. The limits of time resolution are tested by imaging the fast moving Caenorhabditis elegans at a discrete wavenumber of 1265 cm–1. Mid‐infrared imaging is performed with the 640 × 480 pixel video graphics array (VGA) standard and at a full‐frame time resolution of 0.02 s (i.e. well above the most common frame rate standards). An average signal‐to‐noise ratio of 16 is obtained. To the best of our knowledge, these findings constitute the first mid‐infrared imaging of living organisms at VGA standard and video frame rate.
There is a clinical need in the treatment of atrial fibrillation by radiofrequency ablation to provide lesion set validation. The integration of optical fibers into radiofrequency ablation catheters can address this issue. Thermally‐induced, dynamic changes in tissue diffuse reflectance are measured through transcatheter near‐infrared spectroscopy. A regression model based on spectral features is proposed and utilized to validate the presence of thermal injury, measure lesion depth, and assess gaps. Further details can be found in the article by Rajinder P. Singh‐Moon, Xinwen Yao, Vivek Iyer, et al. ( e201800144 ).
This review is aimed at interpreting development and advantages of intravital imaging as an emerging invaluable methodology and summarizing related representative discoveries in bone physiologies and pathologies. It also indicates current limitations, further refinement, and extended application of intravital imaging in bone research. Further details can be found in the article by Yuhao Liu, Quan Yuan, and Shiwen Zhanget ( e201960075 ).
Label‐free optical projection tomography technique makes it possible for quantitative whole mouse embryo imaging without any exogenous contrast agent. Further details can be found in the article by Sungbea Ban, Nam Hyun Cho, Eunjung Min, et al. ( e201800481 ).
Nuclear pore complex imaged at three different resolutions by confocal, expansion, and Ex‐STED microscopy, respectively. NUP become a ruler to measure the expansion process. Further details can be found in the article by Luca Pesce, Marco Cozzolino, Luca Lanzanò, Alberto Diaspro, and Paolo Bianchini ( e201900018 ).
下载免费PDF全文