Journal of biophotonics最新文献

Photobiomodulation (PBM) with red or near-infrared (NIR) light enhances mitochondrial metabolism and tissue repair, yet its safety regarding malignant cells remains under debate. This study examined wavelength- and fluence-dependent PBM effects on skeletal muscle and cancer cells. Murine myoblasts (C2C12) and human lung adenocarcinoma cells (A549) were exposed to 660 nm LED or 830 nm NIR laser light at 0-20 J/cm². Viability (CCK-8), reactive oxygen species (ROS), and ATP levels were quantified. PBM produced a biphasic response in C2C12, with maximal viability and ATP at 5 J/cm² under NIR and moderate ROS elevation. Conversely, A549 showed stable or slightly reduced viability despite increased ROS, suggesting a distinct redox sensitivity. Both wavelengths enhanced mitochondrial activity in muscle cells while avoiding overstimulation in carcinoma cells. These wavelength- and cell type-specific effects indicate the bioenergetic safety of PBM and its potential for muscle regeneration research.

Histopathology remains the gold standard for definitive tumor diagnosis after surgical resection; however, its lengthy processing time can delay critical postoperative care. Hyperspectral imaging (HSI) is emerging as a promising label-free technique for rapid biochemical tissue assessment. Here, we present HyperProbe1.1 (HP1.1), an HSI system designed for noninvasive analysis of fresh brain tumor biopsies. In this proof-of-concept study, we applied the HP1.1 system to freshly excised meningioma specimens-the most common primary intracranial tumors. The platform enabled rapid, label-free mapping of metabolic activity and vascular heterogeneity, while spectral unmixing further allowed the quantification of endogenous biomarkers such as cytochrome c oxidase (CCO), hemoglobin derivatives, and lipids, revealing molecular patterns consistent with histopathological tumor grading according to the 2021 WHO classification. These results highlight the feasibility of HSI for rapid biochemical tissue assessment and its potential integration into intraoperative decision-making.

Photobiomodulation (PBM) a promising non-invasive therapeutic technique has been proposed to have regenerative ability. There is limited understanding of PBMs effectiveness in 3D cell culture systems. To evaluate the effect of PBM at 825 nm on adipose-derived stem cells (ADSCs) cultured in 2D and 3D spheroid models. ADSCs were exposed to PBM at fluences of 5, 10, and 15 J/cm² to assess cellular responses. Cell morphology, spheroid diameter, cell concentration, viability, proliferation, and cytotoxicity were monitored 24- and 72-h post-irradiation (hpi). In 2D cell culture, PBM at 5 J/cm² showed a significant increase in cell viability and proliferation. Cellular cytotoxicity was higher in 2D. Spheroids maintained steady size, increased viability, and proliferation peaking at 24 hpi but remaining stable over time at 10 J/cm². 2D cell cultures show an over expression of PBM-induced effects, while spheroids provide a more physiological and balanced response profile particularly at 10 J/cm².

Three-dimensional (3D) cell models provide a physiologically relevant environment similar for improving drug screening. However, subcellular structure observation remains challenging due to light scattering. This study developed 3D HeLa cell spheroids in gelatin methacryloyl (GelMA) hydrogel as the in vitro 3D cell model for drug screening. A 4.6-fold expansion protocol enabled in situ high-resolution 3D mitochondrial imaging for cell spheroids cultured in GelMA. Notably, to our knowledge, this is the first instance of revealing mitochondrial morphology at the individual mitochondrial level within cell spheroids. Furthermore, quantitative analysis reveals the mitochondrial morphology change after drug treatment. This work establishes a high-content 3D cell model-based drug screening method, in which in situ subcellular structure imaging in 3D cell spheroids embedded in GelMA can be achieved with unprecedented resolution (about 90 nm) by commercial confocal microscope, facilitating a deeper understanding of drug mechanisms in cell spheroid-based drug screening.

Background: Clear cell renal cell carcinoma (ccRCC), the most common aggressive renal cancer subtype, shows marked heterogeneity that hinders recurrence prediction.

Objective: To evaluate hyperspectral pathology imaging (HSI) with deep learning for individualized recurrence risk prediction in ccRCC.

Methods: Slides from 48 patients with ccRCC were imaged using a 400-1000 nm hyperspectral microscope. Spectral data were preprocessed, and a dual-branch network (HSI-FusionNet) extracted spatial and spectral features via 2D and 1D convolution, followed by gated fusion and multiple instance learning (MIL) for patient-level prediction.

Results: HSI-FusionNet achieved strong test performance (area under the receiver operating characteristic curve [AUC] = 0.912; sensitivity = 0.881; specificity = 0.846), outperforming ResNet-50, 1D-Convolutional Neural Network (CNN), and a 1D-Transformer. Recurrence-related spectral bands (530-580 and 830-900 nm) reflected hemoglobin and lipid-collagen differences.

Conclusion: HSI with deep learning accurately identifies recurrent ccRCC and reveals molecular-metabolic signatures, supporting precision postoperative risk stratification.

Although the germicidal effects of UV radiation are well documented, its impact on the germination behavior of individual spores remains poorly understood. This study employed single-spore optical analysis to investigate how UV exposure affects Bacillus thuringiensis (Bt) and Lysinibacillus sphaericus (Ls) spores and their germination. Following 2-10 min of UV treatment, spore viability declined to 76%-16% for Bt and 74%-3.3% for Ls. Increased exposure was associated with reduced CaDPA content, decreased intensity at 1280 cm^-1, and increased band ratios (1243/1257 cm^-1 and 1662/1650 cm^-1), indicating structural alterations in amide III and I regions of proteins due to radiation. UV exposure delayed germination responses to both nutrient and non-nutrient germinants, as evidenced by prolonged lag times, extended CaDPA release, and slower cortex lysis. Furthermore, germination heterogeneity increased among individual spores. Collectively, these findings suggest UV radiation likely impairs germination-related proteins, leading to delayed and desynchronized spore germination.

Accurate intraoperative determination of bowel viability remains unresolved, as current assessments are subjective and dye-based methods cannot capture reperfusion dynamics. Laser speckle contrast imaging (LSCI) offers a dye-free, real-time, and repeatable approach for quantifying tissue perfusion. We conducted a two-phase rat study to establish a quantitative threshold and validate its predictive value for ischemic recovery. In Phase 1 (n = 6), ischemia (30-180 min) was induced, and LSCI ratios at 60 min after reperfusion were analyzed. A ratio ≥ 0.8 defined viability, whereas < 0.5 indicated irreversible damage. In Phase 2 (n = 4), this threshold was prospectively tested in a survival model. Segments subjected to ≤ 90 min ischemia recovered, the 120-min case showed delayed but complete recovery, while 150 min led to necrosis. This is the first experimental demonstration that LSCI can predict bowel recovery after reperfusion, providing a novel, objective framework for intraoperative viability assessment.

When illuminated with green light, tissue shows negligible autofluorescence in comparison to urinary stones. In automatically controlled lithotripsy, this property is utilized to prevent the laser from being triggered if the fiber is mispositioned: the fluorescence signal is compared to a set threshold before each pulse. However, previous studies have shown that tissue damage cannot be completely ruled out. We are investigating this phenomenon and its impact on fluorescence guidance. An experiment with porcine calyx (with the automatic control switched off) shows that single Ho:YAG laser pulses are sufficient to coagulate tissue, resulting in an increase in autofluorescence. During lithotripsy of fluorescent artificial stones embedded in renal cortex, thermal damage occurs despite automatic laser control. Maximum fluorescence values measured on those tissue places were above the control's set threshold for laser emission. Therefore, an increase in autofluorescence in the event of denaturation must be considered when using automatically controlled lithotripsy.

Laser treatment of natural canals is typical for phlebology, gynecology and urology. This method has several problems, including the choice of light dosimetry and instrumentation. It is important to provide a reliable and uniform energy distribution on the canal walls. Aimed at this, a sapphire tip is proposed in this work. Manufactured by the crystal growth technique, this tip has miniature dimensions and an axial cavity, which serves as a reflecting element. It can be combined with standard optical fibers providing contact coagulation. In this work, the performance of this instrument was studied numerically and experimentally, using ex vivo liver samples. The results reveal an ability of the tip to form local coagulation without a sharp increase in temperature on the instrument surface. Thus, the sapphire tip demonstrates significant prospects for interstitial laser treatment, combining simple design, high reliability, reproducibility of the light distribution, and a smoothed thermal profile.

Age-related macular degeneration is a disease that affects the middle part of the vision and involves pathological alterations in the retinal pigment epithelium. Accurate and timely evaluation of the retinal pigment epithelium is a cornerstone of effective treatment planning. In this study, we present the development of a preclinical method for early diagnostics of age-related macular degeneration using time and spectral characteristics of fluorescence of lipofuscin granules from the retinal pigment epithelium. Using the unique system based on a superconducting single-photon detector and time-correlated single-photon counting electronics integrated in the confocal laser scanning microscope we determined the parameters of fluorescence (distribution long and short fluorescence lifetime components and their contribution to the total fluorescence signal as well as fluorescence spectral shift) that have a diagnostic value for differentiation of the normal and pathological states in the degenerative diseases of the retina and retinal pigment epithelium.