Biomedical optics express最新文献

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder that requires objective and repeatable assessment of both tissue structure and disease activity for proper management of the disease. Multimodal endoscopy combining optical coherence tomography (OCT) and fluorescence imaging offers complementary structural and functional contrast for this purpose. However, conventional double-clad fiber catheters often suffer from multipath interference artifacts that degrade structural image fidelity. Here, we present a fully integrated dual-modality endoscopic system enabling artifact-suppressed OCT alongside high-sensitivity fluorescence imaging. We utilized this system to longitudinally monitor the progression of dextran sulfate sodium (DSS)-induced colitis in mice in vivo. The imaging results revealed distinct stage-specific biomarkers, where acute inflammation was characterized by profound vascular permeability, while the chronic phase was distinguished by persistent thickening of the muscularis layer. An exploratory random forest classifier trained on these extracted features achieved a diagnostic accuracy of 96.7% in distinguishing different colitis states, with feature importance analysis confirming the synergistic value of combining both the structural and fluorescence information. This work establishes a robust multimodal endoscopic platform for non-invasive, longitudinal quantification of inflammatory burden in preclinical models, with potential applications in diagnostic imaging and treatment monitoring of gastrointestinal diseases.

Simultaneous multicolor whole-brain imaging with cytoarchitectural reference is critical for neural circuit mapping, but sequential scanning prolongs acquisition and complicates inter-channel registration. We developed a three-color high-definition fluorescent micro-optical sectioning tomography (HD-fMOST) system for three-channel high-throughput imaging of the whole mouse brain. We corrected chromatic aberration in the 405 nm illumination path and designed a precision 6-axis stage for pixel-level registration of three channels. Real-time DAPI counterstaining provides cytoarchitectural landmarks while preserving green/red fluorescence excitation. The system achieves sub-micron voxel resolution (0.32 × 0.32 × 1 μm³) and a high signal-to-background ratio. Validation on dual-color-labeled mouse brain demonstrates high-precision whole-brain imaging, accurate structural colocalization, and quantitative single-neuron morphological reconstruction.

Designing more effective myopia control optical-based therapies requires a better understanding of the longitudinal changes in retinal image quality across the central and peripheral retina of children with different refractive profiles. To this end, we computed through-focus image quality descriptors from ocular aberrations measured across an eccentricity range of 60°, with data acquired biannually over three years in 62 children with initial functional emmetropia participating in the PICNIC study. Our results reveal distinct spatiotemporal optical signatures associated with myopia development: longer peripheral depth of focus and reduced image quality at the near-temporal and central retina even after foveal correction, and placement of the sharpest images behind the temporal retina.

Continuous-wave functional near-infrared spectroscopy (CW-fNIRS) traditionally utilizes fixed-geometry optode configurations, which introduce significant anatomical bias due to inter-subject variations in skull thickness and phenotypic barriers such as dense hair. To address these limitations, we propose an Optical Adaptive Depth Steering (O-ADS) framework that mathematically synthesizes a "Virtual Optode" using a high-density multi-distance array (8-32 mm) and a linearly constrained minimum variance (LCMV) spatial beamformer. We computationally validated this framework using high-fidelity Monte Carlo simulations on layered cranial slabs and a 3D anatomical atlas (Colin27). Results demonstrate that O-ADS exhibits high computational resilience to anatomical bias, achieving up to a 39-fold improvement in relative brain sensitivity for thick-skull morphologies compared to traditional 32 mm static sensors. Furthermore, under realistic spatiotemporal noise conditions involving heterogeneous scalp hemodynamics and simulated phenotypic barriers (8 mm reference channel failure), O-ADS maintained a significantly higher mean signal recovery purity (38.3% ± 22.1%) than standard Multi-Distance Regression (MDR) (21.8% ± 15.4%). This software-defined approach provides a scalable solution for optical neuroimaging, reducing the dependence of sensor performance on individual anatomical and phenotypic variance to facilitate more inclusive cerebral monitoring under challenging physical constraints.

Adaptive optics scanning light ophthalmoscopes configured in a two-detector split-detection arrangement enable resolution of translucent retinal structures, producing phase contrast-based images of the retina's topography. Standard two-detector systems that use an edge mirror have reduced contrast for structures that lie perpendicular to the axis of the split mirror, reducing sensitivity and applicability of this technique. Here, rather than manipulating the axis of the split mirror (e.g. using a micromirror device), we rotate the light itself using a Dove prism and compare the approach to a two-detector configuration. We were able to resolve structures at multiple orientations in split-detection images using the Dove prism and combine them using a technique previously reported for four-detector devices.

This work introduces g₁-dOCT, which derives a dynamic index I_d from the first-order field autocorrelation function for long-term tissue viability assessment. The method encodes activity intensity directly as image brightness, offering intuitive interpretability without complex post-processing. Its key advantage lies in the stability of I_d across varying imaging conditions, enabling direct semi-quantitative comparison of tissue activity in longitudinal drug studies, particularly well-suited for pharmacological screening in high-throughput settings, such as multi-drug treatment of 3D tissue constructs in 48-well plates. Experimental validation on tumor slices during 46-hour chemotherapy and on dynamic hepatocyte apoptosis shows that g₁-dOCT maintains consistent performance over extended time courses, establishing it as a reliable tool for longitudinal tissue dynamics evaluation in large-scale drug screening.

Spiral optics have been proposed to extend depth of focus through controlled phase modulation. We characterized the RayOne Galaxy spiral intraocular lens using high-resolution Mach-Zehnder interferometry and a simulated pseudophakic Arizona eye model. Wavefronts were decomposed into Zernike polynomials and compared with monofocal, trifocal, and spherical-aberration-based extended-depth-of-focus (EDOF) lenses. The Galaxy exhibited a smooth EDOF profile with a moderate reduction in contrast rendering. Symmetry analysis showed that radially symmetric aberrations primarily generated the EDOF effect, while the spiral component played a secondary role.

This feature issue of Biomedical Optics Express presents 13 original research articles that highlight recent innovations and current directions in optical sensing and imaging for biomedical research and translation. The contributions span several major areas, including machine learning and image processing; microscopy; optical coherence tomography; optical diagnostics and optics in biotechnology; tissue optics and spectroscopy; and terahertz spectroscopy. Together, these studies advance optical methods for quantitative assessment of molecular, cellular, tissue, and physiological features, with applications including collagen remodeling characterization, ocular and vascular imaging, cortical functional assessment, cancer-related tissue and cell evaluation, and cartilage optical-property estimation. The collection highlights the integration of optical instrumentation, computational analysis, and clinical validation toward more quantitative and application-oriented biomedical optics.

Our study demonstrates that a compact, low-cost, phantom-calibrated diffuse reflectance spectroscopy system can provide realistic estimates of tissue optical properties, supporting its progression toward in situ cartilage diagnostics. We developed and validated a fiber-based DRS system capable of quantitative estimation of absorption coefficient (µ_a) and reduced scattering coefficient (µ_s') in cartilage using a phantom-derived calibration model at wavelengths of 660, 780, and 850 nm. Diffuse reflectance spectra were acquired using a custom-built multi-distance probe, corrected using wavelength-specific calibration coefficients derived from optical phantoms, and fitted using diffusion theory with extrapolated boundary correction to recover µ_a and µ_s'. Our system was validated using phantoms with known optical properties, calibrated to correct system response, and applied to articular cartilage. Theoretical and measured reflectance showed an excellent agreement (bias ∼0, 95% limits of agreement ±0.0114). After calibration, µ_a and µ_s' were extracted from bovine patellar cartilage at the same wavelengths. The estimated µ_a values (0.07-0.24 cm^-1) were characteristic of weakly absorbing, hydrated soft tissue, while µ_s' values (9.7-15.8 cm^-1) showed the expected consistent decrease with wavelength. We found our estimated optical properties were consistent with literature trends, especially µ_s' values, which were between the range reported for µ_s' values from integrating-sphere and Monte Carlo-based analysis for bovine cartilage. Phantom-calibrated DRS enables accurate, reproducible estimation of cartilage optical properties, providing a validated framework for future translation toward arthroscopic optical assessment of joint health.

Patient-derived tumor organoids (PDTOs) are vital for precision oncology, but standard drug screening methods, including adenosine triphosphate (ATP) assays, are destructive and prevent longitudinal monitoring. Optical coherence tomography (OCT) offers non-destructive 3D imaging, capturing morphological features and tissue attenuation characteristics via the optical attenuation coefficient (OAC). Here, we propose a non-destructive evaluation framework for tumor organoids that fuses OAC and multi-dimensional morphological features. Using intrahepatic cholangiocarcinoma (iCCA) PDTOs treated with icaritin, we found that OAC exhibited a significant dose-dependent increase (up to 32.8% at 80 μM compared to control), accompanied by a morphological transition of cystic organoids into solid phenotypes. By integrating these features via K-means++ clustering and principal component analysis, we constructed a relative growth score. This fusion score correlated strongly with the ATP gold standard (Pearson correlation coefficient r = 0.938), outperforming a morphology-only model (r = 0.906). Furthermore, independent experiments with first-line chemotherapeutics (e.g., 5-Fluorouracil, Gemcitabine) and combinatorial regimens indicated the model's potential generalizability (r = 0.887). This method overcomes the limitations of destructive, single-metric evaluations, providing a quantitative and non-destructive platform for high-throughput drug screening and personalized treatment decision-making.