A novel urine analysis technique combining affinity chromatography with Au nanoparticle‐based SERS spectroscopy for potential applications in noninvasive gastric cancer and breast cancer screening. Both the gastric cancer and the breast cancer group can be discriminated from the normal group using SERS spectroscopy combined multivariate diagnostic algorithm, leading to high diagnostic accuracy. These results demonstrate that the urine analysis method has great potential for cancer detection in liquid biopsies. Further details can be found in the article by Xueliang Lin, Lingna Wang, Huijing Lin, et al. ( e201800327 ).
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 ).
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 ).
A reflection‐mode switchable subwavelength Bessel‐beam (BB) and Gaussian‐beam (GB) photoacoustic microscopy (PAM) system has been developed. For the first time, the lateral resolution and the depth‐of‐field of the BB‐ and GB‐PAM were measured. It was demonstrated that BB‐PAM is a powerful tool for a wide range of biomedical research including RBC migration in blood vessels at various depths in vivo and observation of cell migration or cell culture. Further details can be found in the article by Byullee Park, Hoyong Lee, Seungwan Jeon, et al. ( e201800215 ).
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 ).
Laser tweezers Raman spectroscopy as a label‐free and non‐invasive technology was employed to examine the colon cancer cells with single base mutation in KRAS gene segment for the first time. As a result of the comparison, a high correct classification was achieved. Our preliminary results showed that the LTRS system has a great potential for further applications in the rapid and label‐free detection of circulating tumor cells in liquid biopsy. Further details can be found in the article by Mengmeng Liu, Xiujie Liu, Zufang Huang, et al. ( e201800332 ).
Cationic gold nanorods stabilized by quaternary ammonium salts (QAS) are a promising tool for photothermal destruction of cancer cells. However, cytotoxicity of the alkanethiol‐QAS limits their medical applications. A novel design of cationic surfactant composed of the quaternary ammonium group and ethylene glycol chain significantly reduces the compound cytotoxicity in the free state while allowing the preparation of stable nanorods with high cellular uptake and lysosomal localization. Further details can be found in the article by Sarka Salajkova, Michal Sramek, David Malinak, et al. ( e201900024 ).
Monitoring the blood‐brain barrier (BBB) permeability plays a key role in assessing drug release with high resolution. In this work, with the help of optical clearing skull window, we not only realized non‐invasive BBB opening by photodynamic therapy, but also developed a method based on spectral‐imaging to in vivo dynamically monitor the changes in BBB permeability. Further details can be found in the article by Wei Feng, Chao Zhang, Tingting Yu, et al. ( e201800330 ).
Hyperspectral scanning laser optical tomography is developed to provide spectrally resolved volume data sets with high spectral resolution for large mesoscopic samples. It can be used to resolve largely overlapping fluorophores, as demonstrated by the 3D fluorescence hyperspectral reconstruction of a dual‐labelled mouse thymus gland sample and to distinguish between signals from autofluorescence of diseased and normal tissue without prior knowledge. Further details can be found in the article by Lingling Chen, Guiye Li, Li Tang, et al. ( e201800221 ).
Near infrared spectroscopy (NIRS) neuroimaging sensors use light source and detector pairs placed over scalp to measure underlying neurophysiology. Source detector separation (SDS) is a critical design parameter and should aim a balanced trade‐off for detected light intensity and sensitivity to brain tissue. In this study, we used multi‐layer digital head models to systematically evaluate the role of SDS on NIRS spatial sensitivity profiles within both healthy and clinical conditions. Further details can be found in the article by Lei Wang, Hasan Ayaz, and Meltem Izzetoglu ( e201900175 ).
An ultrafast time‐stretch imaging technique for edge detection is demonstrated. The edge detection based on the optical directional derivative is realized by using differential detection. Since the edge detection is implemented in the physical layer, the computation complexity in the back‐end digital signal processing is very low. The blood red cells and cancer cells can be easily identified by distinguishing the edges. Further details can be found in the article by Bo Dai, LuHe, Lulu Zheng, Yongfeng Fu et al. ( e201800044 ).
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 ).
A novel Widefield frequency‐domain fluorescence lifetime imaging system based on a ultrafast sCMOS sensor is reported. It can do parallel multi‐frequency FLIM up to 620MHz in one measurement with 64 phase images. With this system, measurement of FRET efficiency at multi‐frequencies is demonstrated in living cells. Meanwhile, the temperature change of living cells can be measured at each pixel based on FLIM of Rhodamine B at different frequencies. Further details can be found in the article by Hongtao Chen, Ning Ma, Keiichiro Kagawa, et al. ( e201800223 ).
Photodynamic inactivation of prions by disulfonated hydroxyaluminum phthalocyanine. Further details can be found in the article by Marie Kostelanska, Jaroslav Freisleben, Zdenka Backovska Hanusova, et al. ( e201800430 ).
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 ).
Optoacoustics (OA) is combined with near‐infrared optical tomography (NIROT) in reflection mode to quantitatively image vasculature oxygen saturation (SO2) levels in phantoms containing vessels at depths up to 25 mm. Using NIROT to estimate the light fluence, the OA signals' spectral distortion was reduced from 60–150% to 10–20%. Results suggest that SO2 levels can be determined with <10% error and that temporal changes can be monitored with even better accuracy. Further details can be found in the article by Leonie Ulrich, Linda Ahnen, Hidayet Günhan Akarçay, et al. ( e201800112 ).
Lens‐free holographic on‐chip microscopy holds tremendous potential to be used for the high‐throughput imaging of pathology slides for clinical diagnosis. However, due to the use of narrowband illumination sources, it is challenging for lens‐free microscopy to achieve a good color accuracy. As a solution to this challenge, an absorbance spectrum estimation‐based colorization (ASEC) method is presented which achieves accurate‐color imaging of pathology slides using only a few (e.g., three) wavelengths. Further details can be found in the article by Yibo Zhang, Tairan Liu, Yujia Huang, et al. ( e201800335 ).
TP‐SAX microscopy images are shown in cyan, cyan hot, red, gray, and orange hot colors; TPFM images are in green color while the LSCM image is in magenta color. Our results show a spatial resolution enhancement for TP‐SAX (cyan image) even at 2.4 mm depth of a mouse brain in comparison with TPFM (green image) where scattering seriously degrades the PSF. Further details can be found in the article by Sandeep Chakraborty, Szu‐Yu Lee, Jye‐Chang Lee, Chen‐Tung Yen, and Chi‐Kuang Sun ( e201800136 ).
A large‐depth‐of‐field full‐field optical angiography (LD‐FFOA) method is developed to expand the depth‐of‐field (DOF). The contrast pyramid fusion algorithm is used to fuse 10 FFOA images at different focus depth. Cover images of mouse ear shows LD‐FFOA image has higher contrast and more detailed features. The LD‐FFOA method solves the defocused problem caused by the limited DOF of lens, the curved surface and uneven thickness of the sample. Further details can be found in the article by Mingyi Wang, Nanshou Wu, Hongheng Huang, et al. ( e201800329 ).
A STED‐FLIM system is developed to observe the changes of fluorescence lifetime. The pictures show increased lifetime of fluorescent microspheres samples with laser illumination time in both confocal and STED imaging modes. Due to the saturation power of fluorophores is correlated with fluorescence lifetime, the lifetime increase is beneficial for the reduction of the saturation power, indicating the same imaging resolution can be achieved in a lower depletion power. Further details can be found in the article by Lu‐Wei Wang, Yue Chen, Wei Yan, et al. ( e201800315 ).
