Journal of Innovative Optical Health Sciences

Although the electrospinning technique has been devoted to promoting therapeutic purposes as a drug carrier, however, there are still many fundamental problems in this area. This work focuses on a comparison of various diameter polyethersulfone (PES) electrospun ultrafine fibers as antimicrobial materials. The fibrous morphology, antimicrobial agent distribution, thermally property, and biocompatibility evaluation of PES-based ultrafine fibers were systematically investigated. The results demonstrated that the PES-based ultrafine fibers were suitable as antimicrobial material. Furthermore, the drug release behavior and mechanism were studied through total immersion. The release mechanism was confirmed to Fickian diffusion. It was revealed that the drug max release amount (71.5%) and release rate (7.71) are the highest for the smallest diameter ultrafine fibers. Meanwhile, the antimicrobial activity of PES ultrafine fibers is also inversely correlated with the diameter of fiber. The electrospun PES fibers would control their release behavior through the diameter and have a potential application in the wound dressings, such as chronic osteomyelitis and exposure injury.

Functionalized black phosphorus (BP) nanosheets have been considered as promising nanoagents in cancer therapy due to their excellent photothermal conversion efficiency. However, it is still difficult to visually monitor the dynamic localization of BP nanoagents in cancer cells. In this paper, we systematically studied the second-harmonic generation (SHG) signals originating from exfoliated BP nanosheets. Interestingly, under the excitation of a high frequency pulsed laser at 950 nm, the SHG signals of BP nanosheets in vitro are almost undetectable because of their poor stability. However, the intracellular SHG signals from BP nanosheets could be measured by in vivo optical imaging due to the efficient enrichment of living HeLa cells. Moreover, the SHG signal intensity from BP nanosheets increases with the prolonged incubation time. It can be expected that the BP nanosheets could be a promising intracellular SHG nanoprobe employed for visually in vivo biomedical imaging in practical cancer photothermal therapy (PIT).

Near-infrared (NIR) light has been shown to produce a range of physiological effects in humans, however, there is still no agreement on whether and how a single parameter, like the flicker frequency of NIR light, affects the brain. An 810nm NIR LED was used as the stimulator. Fifty subjects participated in this experiment. Forty subjects were randomly divided into four groups. Each group underwent a 30-minute NIR LED radiation with four different frequencies (i.e., 0Hz, 5Hz, 10Hz and 20Hz, respectively) on the forehead. The remaining 10 subjects formed the control group, in which they underwent a 30-minute rest period without light radiation. EEG signals of all subjects during each test were recorded. Gravity frequency (GF), relative energy change, and sample entropy were analyzed. The experimental groups had larger GF values compared to the control group. Higher stimulation frequency would cause larger growth of GF ($F=14.75$, $P<0.001$). The amplitude of alpha waves relative energy increased, while theta waves decreased remarkably in the experimental groups ($p<0.02$), and the extent of increase/decrease was larger at higher stimulation frequency, compared to that of the control. Sample entropy of electrodes in the frontal areas were much larger than those in other brain areas in the experimental groups ($p<0.001$). Larger frequency of the NIR LED light would cause more distinct brain activities in the stimulated areas. It indicates that NIR LED light may have a positive effect on modulating brain activity. These results may help improve the design of photobiomodulation treatments in the future.

Fluorescence imaging is very useful for skin cancer lesions detection because of its properties of noninvasion and fast imaging. However, conventional fluorescence imaging devices’ excitation light source and camera are usually separated, which will cause problems such as complicated structure, large volume, and poor illumination homogeneity. In this paper, we introduce a miniature portable fluorescence imaging device to diagnose skin cancer. A coaxial design has been introduced to combine the exciting light source and fluorescence receiver as an integral part, which significantly reduces the size of the device and ensures illumination homogeneity. The volume of the device is less than $3.5\times 3.5\times 9.5$cm³ with weight of 150g, and the total power (including the excitation lamp) is only 1.5 W. It is used to detect the squamous cell carcinoma mice for demonstration. The results show that the location of the cancer lesions can be easily distinguished from the images captured by the device. It can be efficiently used to detect early skin tumors with noninvasion. It also has prospects to be integrated with other diagnostic methods such as ultrasound probe, for multiple diagnose of skin tumors thanks to its miniature size.

Structured illumination microscopy (SIM) is a rapidly developing super-resolution technology. It has been widely used in various application fields of biomedicine due to its excellent two- and three-dimensional imaging capabilities. Furthermore, faster three-dimensional imaging methods are required to help enable more research-oriented living cell imaging. In this paper, a fast and sensitive three-dimensional structured illumination microscopy based on asymmetric three-beam interference is proposed. An innovative time-series acquisition method is employed to halve the time required to obtain each raw image. A segmented half-wave plate as a substantial linear polarization modulation method is applied to the three-dimensional SIM system for the first time. Although it needs to acquire 21 raw images instead of 15 to reconstruct one super-resolution image, the SIM setup proposed in this paper is 30% faster than the traditional spatial light modulator-SIM (SLM-SIM) in imaging each super-resolution image. The related theoretical derivation, hardware system, and verification experiment are elaborated in this paper. The stable and fast 3D super-resolution imaging method proposed in this paper is of great significance to the research of organelle interaction, intercellular communication, and other biomedical fields.

The intra-operative real-time assessment of tissue viability can potentially improve therapy delivery and clinical outcome in cardiovascular therapies. Cardiac ablation therapy for the treatment of supraventricular or ventricular arrhythmia continues to be done without being able to assess if the intended lesion and lesion size have been achieved. Here, we report a method for continuous measurements of cardiac muscle microcirculation to provide an instrument for real-time ablation monitoring. We performed two acute open chest animal studies to assess the ability to perform real-time monitoring of creation and size of ablation lesion using a standard RF irrigated catheter. Radiofrequency ablation and laser Doppler were applied to different endocardial areas of alive open-chest pig. We performed two experiments at three different RF ablation energy setting and different ablation times. Perfusion signals before and after ablation were found extensively and distinctively different. By increasing the ablation energy and time, the perfusion signal was decreasing. In vivo assessing the local microcirculation during RF ablation by laser Doppler can potentially be useful to differentiate between viable and nonviable ablated beating heart in real time.

Image reconstruction in fluorescence molecular tomography involves seeking stable and meaningful solutions via the inversion of a highly under-determined and severely ill-posed linear mapping. An attractive scheme consists of minimizing a convex objective function that includes a quadratic error term added to a convex and nonsmooth sparsity-promoting regularizer. Choosing ${\ell }_1$-norm as a particular case of a vast class of nonsmooth convex regularizers, our paper proposes a low per-iteration complexity gradient-based first-order optimization algorithm for the ${\ell }_1$-regularized least squares inverse problem of image reconstruction. Our algorithm relies on a combination of two ideas applied to the nonsmooth convex objective function: Moreau–Yosida regularization and inertial dynamics-based acceleration. We also incorporate into our algorithm a gradient-based adaptive restart strategy to further enhance the practical performance. Extensive numerical experiments illustrate that in several representative test cases (covering different depths of small fluorescent inclusions, different noise levels and different separation distances between small fluorescent inclusions), our algorithm can significantly outperform three state-of-the-art algorithms in terms of CPU time taken by reconstruction, despite almost the same reconstructed images produced by each of the four algorithms.

Photodynamic therapy (PDT) has become an attractive tumor treatment modality because of its noninvasive feature and low side effects. However, extreme hypoxia inside solid tumors severely impedes PDT therapeutic outcome. To overcome this obstacle, various strategies have been developed recently. Among them, in situ oxygen generation, which relies on the decomposition of tumor endogenous H₂O₂, and oxygen delivery tactic using high oxygen loading capacity of hemoglobin or perfluorocarbons, have been widely studied. The in situ oxygen generation strategy has high specificity to tumors, but its oxygen-generating efficiency is limited by the intrinsically low tumor H₂O₂ level. In contrast, the oxygen delivery approach holds advantage of high oxygen loading efficiency, nevertheless lacks tumor specificity. In this work, we prepared a nanoemulsion system containing H₂O₂-responsive catalase, highly efficient oxygen carrier perfluoropolyether (PFPE), and a near-infrared (NIR) light activatable photosensitizer IR780, to combine the high tumor specificity of the in situ oxygen generation strategy and the high efficiency of the oxygen delivery strategy. This concisely prepared nanoplatform exhibited enhanced and H₂O₂-controllable production of singlet oxygen under light excitation, satisfactory cytocompatibility, and ability to kill cancer cells under NIR light excitation. This highlights the potential of this novel nanoplatform for highly efficient and selective NIR light mediated PDT against hypoxic tumors. This research provides new insight into the design of intelligent nanoplatform for relieving tumor hypoxia and enhancing the oxygen-dependent PDT effects in hypoxic tumors.

The main aim of this paper is to investigate the corneal damage effects induced by mid-infrared optical parametric oscillator (OPO) radiation. Experiments were performed to determine the corneal damage thresholds of New Zealand white rabbit at the wavelength of 3743nm for exposure durations of 0.1s, 1.0s and 10.0s. Through slit-lamp biomicroscope and histopathology, corneal injury characteristics were revealed. The damage thresholds were 3.73J/cm², 7.91J/cm² and 31.1J/cm², respectively, for exposure durations of 0.1s, 1.0s and 10.0s. The damage data was correlated by an empirical equation: Radiant exposure at the $\mathrm{\text{threshold}}=9.72\times \mathrm{\text{exposure}}$ duration,${}^{0.46}$ where the units of radiant exposure and exposure duration were J/cm² and second. At near-threshold level, corneal injuries at 1 h post-exposure mainly involved the epithelium, and the epithelium damages repaired at 24-h post-exposure. There are sufficient safety margins between the damage thresholds and the maximum permitted exposures from current international laser safety standard IEC 60825-1.

Fluorescence recovery after photobleaching (FRAP) and single particle tracking (SPT) techniques determine the diffusion coefficient from average diffusive motion of high-concentration molecules and from trajectories of low-concentration single molecules, respectively. Lateral diffusion coefficients measured by FRAP and SPT techniques for the same biomolecule on cell membrane have exhibited inconsistent values across laboratories and platforms with larger diffusion coefficient determined by FRAP, but the sources of the inconsistency have not been investigated thoroughly. Here, we designed an image-based FRAP-SPT system and made a direct comparison between FRAP and SPT for diffusion coefficient of submicron particles with known theoretical values derived from Stokes–Einstein equation in aqueous solution. The combined $i$FRAP-SPT technique allowed us to measure the diffusion coefficient of the same fluorescent particle by utilizing both techniques in a single platform and to scrutinize inherent errors and artifacts of FRAP. Our results reveal that diffusion coefficient overestimated by FRAP is caused by inaccurate estimation of the bleaching spot size and can be corrected by simple image analysis. Our $i$FRAP-SPT technique can be potentially used for not only cellular membrane dynamics but also for quantitative analysis of the spatiotemporal distribution of the solutes in small scale analytical devices.