Journal of Innovative Optical Health Sciences

The fluorescence-based in vivo flow cytometry (IVFC) is an emerging tool to monitor circulating cells in vivo. As a noninvasive and real-time diagnostic technology, the fluorescence-based IVFC allows long-term monitoring of circulating cells without changing their native biological environment. It has been applied for various biological applications (e.g., monitoring circulating tumor cells). In this work, we will review our recent works on fluorescence-based IVFC. The operation principle and typical biological applications will be introduced. In addition, the recent advances in IVFC flow cytometry based on photoacoustic effects and other label-free detection methods such as imaging-based methods, diffuse-light methods, hybrid multimodality methods and multispectral methods are also summarized.

Learning-based methods have been proved to perform well in a variety of areas in the biomedical field, such as biomedical image segmentation, and histopathological image analysis. Deep learning, as the most recently presented approach of learning-based methods, has attracted more and more attention. For instance, massive researches of deep learning methods for image reconstructions of computed tomography (CT) and magnetic resonance imaging (MRI) have been reported, indicating the great potential of deep learning for inverse problems. Optical technology-related medical imaging modalities including diffuse optical tomography (DOT), fluorescence molecular tomography (FMT), bioluminescence tomography (BLT), and photoacoustic tomography (PAT) are also dramatically innovated by introducing learning-based methods, in particular deep learning methods, to obtain better reconstruction results. This review depicts the latest researches on learning-based optical tomography of DOT, FMT, BLT, and PAT. According to the most recent studies, learning-based methods applied in the field of optical tomography are categorized as kernel-based methods and deep learning methods. In this review, the former are regarded as a sort of conventional learning-based methods and the latter are subdivided into model-based methods, post-processing methods, and end-to-end methods. Algorithm as well as data acquisition strategy are discussed in this review. The evaluations of these methods are summarized to illustrate the performance of deep learning-based reconstruction.

Functional near-infrared spectroscopy (fNIRS), a growing neuroimaging modality, has been utilized over the past few decades to understand the neuronal behavior in the brain. The technique has been used to assess the brain hemodynamics of impaired cohorts as well as able-bodied. Neuroimaging is a critical technique for patients with impaired cognitive or motor behaviors. The portable nature of the fNIRS system is suitable for frequent monitoring of the patients who exhibit impaired brain activity. This study comprehensively reviews brain-impaired patients: The studies involving patient populations and the diseases discussed in more than 10 works are included. Eleven diseases examined in this paper include autism spectrum disorder, attention-deficit hyperactivity disorder, epilepsy, depressive disorders, anxiety and panic disorder, schizophrenia, mild cognitive impairment, Alzheimer’s disease, Parkinson’s disease, stroke, and traumatic brain injury. For each disease, the tasks used for examination, fNIRS variables, and significant findings on the impairment are discussed. The channel configurations and the regions of interest are also outlined. Detecting the occurrence of symptoms at an earlier stage is vital for better rehabilitation and faster recovery. This paper illustrates the usability of fNIRS for early detection of impairment and the usefulness in monitoring the rehabilitation process. Finally, the limitations of the current fNIRS systems (i.e., nonexistence of a standard method and the lack of well-established features for classification) and future research directions are discussed. The authors hope that the findings in this paper would lead to advanced breakthrough discoveries in the fNIRS field in the future.

Objective: We study the biomedical optical properties of the color light and near-infrared fluorescence separated-merged imager.

Materials and Methods: The color light and near-infrared fluorescence separated-merged imager can illuminate the visible light and the near-infrared light of $760\pm 10$nm, receiving the reflected light and $835\pm 10$nm near-infrared fluorescence, and display the color, fluorescence and merge image. ICG solution of different concentration, including standing time, was allocated to study the best imaging condition in vitro, and the depth of fluorescence penetration was studied with 5% agarose gel; the imaging characteristics of the imager was studied using SD rat; and then the SLNs tracing in 4 cases of penile carcinoma was performed.

Results: When the concentration of ICG is 13.11$\mu$mol/L, the fluorescence intensity and the merge image are the best. The maximum depth of fluorescence imaging is 9mm in 5% agarose gel, while the bone has the greatest influence on it. The SLNs tracing shows that the imager can locate the SLNs in vitro, to achieve perioperative navigation during biopsy.

Conclusion: There are many factors that affect the imaging effect, but the imaging effect of the imager meets the requirement of vision in a wide range, and can effectively trace the SLNs in perioperative period.

Rodents are popular biological models for physiological and behavioral research in neuroscience and rats are better models than mice due to their higher genome similarity to human and more accessible surgical procedures. However, rat brain is larger than mice brain and it needs powerful imaging tools to implement better penetration against the scattering of the thicker brain tissue. Three-photon fluorescence microscopy (3PFM) combined with near-infrared (NIR) excitation has great potentials for brain circuits imaging because of its abilities of anti-scattering, deep-tissue imaging, and high signal-to-noise ratio (SNR). In this work, a type of AIE luminogen with red fluorescence was synthesized and encapsulated with Pluronic F-127 to make up form nanoparticles (NPs). Bright DCDPP-2TPA NPs were employed for in vivo three-photon fluorescent laser scanning microscopy of blood vessels in rats brain under 1550nm femtosecond laser excitation. A fine three-dimensional (3D) reconstruction up to the deepness of 600$\mu$m was achieved and the blood flow velocity of a selected vessel was measured in vivo as well. Our 3PFM deep brain imaging method simultaneously recorded the morphology and function of the brain blood vessels in vivo in the rat model. Using this angiography combined with the arsenal of rodent’s brain disease, models can accelerate the neuroscience research and clinical diagnosis of brain disease in the future.

In this paper, in vivo spectra from 23 patients’ blood samples with various Creatinine (Cr) concentration levels ranging from 0.96 to 12.5 mg/dL were measured using Fourier transform near-infrared spectrometer (FT-NIRS) and spectrum quantitative analysis method. Since Cr undergoes passive filtration, it serves as a key biomarker of kidneys function via the estimation of glomerular filtration rate. Thus, increased blood Cr concentration reflects impaired renal function. After spectra pre-processing and outlier exclusion, a spectral model was developed based on partial least squares regression (PLSR) method, wherein Cr concentrations correlated with filtered NIR spectra across several peaks, where Cr is known to absorb NIR light. Several statistical metrics were applied to estimate the model efficiency during data analysis. Comparison of spectra-derived concentrations to reference Cr measurements by the current gold-standard Jaffe’s method held in hospital lab revealed a Cr prediction accuracy of 1.64mg/dL with good correlation of $R=0.9$. Bland-Altman plots were used to compare between our calculations and reference lab values and reveal minimal bias between the two. The finding presented the potential of FT-NIRS coupled with PLSR technique for Cr determination.

In this work, a solely gravity and capillary force-driven flow chemiluminescence (GCF-CL) paper-based microfluidic device has been proved for the first time as a new platform for inexpensive, usable, minimally-instrumented dynamic chemiluminescence (CL) detection of chromium (III) [Cr(III)], where an appropriate angle of inclination between the loading and detection zones on the paper produces a rapid flow of CL prompt solution through the paper channel. For this study, we use a cost-effective paper device that is manufactured by a simple wax screen-printing method, while the signal generated from the Cr(III)-catalyzed oxidation of luminol by H₂O₂ is recorded by a low-cost and luggable CCD camera. A series of GCF-CL affecting factors have been evaluated carefully. At optimal conditions, two linear relationships between GCF-CL intensities and the logarithms of Cr(III) concentrations are obtained in the concentration ranges of 0.025–35mg/L and 50–500mg/L separately, with the detection limit of 0.0245mg/L for a less than 30s assay, and relative standard deviations (RSDs) of 3.8%, 4.5% and 2.3% for 0.75, 5 and 50mg/L of Cr(III) ($n=8$). The above results indicate that the GCF-CL paper-based microfluidic device possesses a receivable sensitivity, dynamic range, storage stability and reproducibility. Finally, the developed GCF-CL is utilized for Cr(III) detection in real water samples.

Algorithms for reconstruction of linear and circular birefringence-dichroism of optically thin anisotropic biological layers are presented. The technique of Jones-matrix tomography of polycrystalline films of biological fluids of various human organs has been developed and experimentally tested. The coordinate distributions of phase and amplitude anisotropy of bile films and synovial fluid taken from the knee joint are determined and statistically analyzed. Criteria (statistical moments of 3rd and 4th orders) of differential diagnostics of early stages of cholelithiasis and septic arthritis of the knee joint with excellent balanced accuracy were determined. Data on the diagnostic efficiency of the Jones-matrix tomography method for polycrystalline plasma (liver disease), urine (albuminuria) and cytological smears (cervical cancer) are presented.

We applied near-infrared (NIR) spectroscopy with chemometrics for the rapid and reagent-free analysis of serum urea nitrogen (SUN). The modeling is based on the average effect of multiple sample partitions to achieve parameter selection with stability. A multiparameter optimization platform with Norris derivative filter–partial least squares (Norris-PLS) was developed to select the most suitable mode $(d=2$, $s=33$, $g=15)$. Using equidistant combination PLS (EC-PLS) with four parameters (initial wavelength $I$, number of wavelengths $N$, number of wavelength gaps $G$ and latent variables LV), we performed wavelength screening after eliminating high-absorption wavebands. The optimal EC-PLS parameters were $I=1228$nm, $N=26$, $G=16$ and $\mathrm{\text{LV}}=12$. The root-mean-square error (SEP), correlation coefficient $(R_P)$ for prediction and ratio of performance-to-deviation (RPD) for validation were 1.03mmolL${}^{-1}$, 0.992 and 7.6, respectively. We proposed the wavelength step-by-step phase-out PLS (WSP-PLS) to remove redundant wavelengths in the top 100 EC-PLS models with improved prediction performance. The combination of 19 wavelengths was identified as the optimal model for SUN. The SEP, $R_P$ and RPD in validation were 1.01mmolL${}^{-1}$, 0.992 and 7.7, respectively. The prediction effect and wavelength complexity were better than those of EC-PLS. Our results showed that NIR spectroscopy combined with the EC-PLS and WSP-PLS methods enabled the high-precision analysis of SUN. WSP-PLS is a secondary optimization method that can further optimize any wavelength model obtained through other continuous or discrete strategies to establish a simple and better model.

Latent membrane protein 1 (LMP1) is known as an oncoprotein in nasopharyngeal carcinoma (NPC) cells, which is considered to have a strong association with growth, invasion and metastasis of NPC cells through lipid rafts. Methyl-$\beta$-cyclodextrin (M$\beta$CD) can disrupt lipid rafts through cholesterol depletion. In this study, we revealed that M$\beta$CD induced apoptosis in two kinds of NPC cells including CNE1 cells, a LMP1-negative nasopharyngeal squamous carcinoma cell line, and CNE1-LMP1 cells, a LMP1-positive nasopharyngeal squamous carcinoma cell line. Furthermore, the impact of M$\beta$CD on LMP1 was investigated by fluorescence resonance energy transfer (FRET) method in NPC cells. Synchronized tempo-spatial and spectral detection of LMP1/LMP1 interaction were performed using fluorescence microscope and spectrograph. FRET efficiency indicated that LMP1/LMP1 interaction gradually enhanced after M$\beta$CD treatment. MTT assays showed that M$\beta$CD caused strong cytotoxicity in CNE1 cells, but caused relatively weaker cytotoxicity in CNE1-LMP1 cells, which indicated that LMP1 may regulate sensitivity of NPC cells to M$\beta$CD. Then, detection of cleaved caspase-3 in two kinds of NPC cells indicated that LMP1 may inhibit activation of caspase-3. These results strongly suggested that M$\beta$CD can induce apoptosis of NPC cells, but enhancing of LMP1/LMP1 interaction may likely resist apoptosis through inhibiting cleavage of caspase-3.

To investigate the effect of Myocardin-related transcription factor A (MRTF-A) on apoptosis induced by ischemic/reperfusion (I/R), middle cerebral artery occlusion/reperfusion (MCAO/R) in rats were applied to mimic I/R. The neurological deficit score, cerebral infarct size, cortical neuron apoptosis and cleaved caspase 3 level were evaluated to determine the effect and the level of apoptosis by TTC straining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) straining, Western blot and immunofluorescence staining. The myeloid cell leukemia-1 (Mcl-1) expression, release of cytochrome C (Cyt C) and its colocalization with apoptotic protease activating factor-1 (Apaf-1) were analyzed by quantitative real-time PCR (qRT-PCR), Western blot, and immunofluorescence staining. The results showed that MRTF-A overexpression could decrease the neurological deficit score and reduce cerebral infarct size ($P<0.01$ versus Sham). In the MRTF-A-I/R group, TUNEL-positive cells and apoptosis ratio (%) ($51.61\pm 6.17$%) were significantly decreased compared to the Neg-I/R group ($76.45\pm 8.77$%) at 24h reperfusion. Meanwhile, the cleaved caspase 3 expression revealed a similar trend while the expression of Mcl-1 was the opposite. Moreover, MRTF-A overexpression significantly enhanced Mcl-1 fluorescence intensity, which up-regulated the mRNA and protein level ($P<0.05$ or $P<0.01$ versus Neg-I/R). Furthermore, MRTF-A overexpression markedly inhibited the release of Cyt C, and decreased the colocalization with Apaf-1 in the cytoplasm ($P<0.05$ or $P<0.01$ versus Neg-I/R). All the data indicated that MRTF-A overexpression could improve the neurological function against cerebral I/R-induced apoptosis since underlying mechanism might be involved in the Mcl-1/Cyt C/cleaved caspase 3 signaling pathway.

Image scanning microscopy based on pixel reassignment can improve the confocal resolution limit without losing the image signal-to-noise ratio (SNR) greatly [C. J. R. Sheppard, “Super-resolution in confocal imaging,” Optik 80(2) 53–54 (1988). C. B. Müller, E. Jörg, “Image scanning microscopy, “Phys. Rev. Lett. 104(19) 198101 (2010). C. J. R. Sheppard, S. B. Mehta, R. Heintzmann, “Superresolution by image scanning microscopy using pixel reassignment,” Opt. Lett. 38(15) 2889–2892 (2013)]. Here, we use a tailor-made optical fiber and 19 avalanche photodiodes (APDs) as parallel detectors to upgrade our existing confocal microscopy, termed as parallel-detection super-resolution (PDSR) microscopy. In order to obtain the correct shift value, we use the normalized 2D cross correlation to calculate the shifting value of each image. We characterized our system performance by imaging fluorescence beads and applied this system to observing the 3D structure of biological specimen.