Journal of biophotonics最新文献

In this study, we aim to validate the analytical Cramer-Rao lower bound (CRLB) equation for determining attenuation coefficients using a 1310 nm Optical Coherence Tomography (OCT) system. Our experimental results successfully confirm the validity of the equation, achieving unprecedented precision with a standard deviation below 0.01 mm^-1 for intralipid samples. Furthermore, we introduce a systematic framework for attaining high precision in OCT attenuation measurements.

Zerumbone is a sesquiterpene phytochemical with cytotoxic activity against cancer. This study aimed to evaluate the effect of zerumbone on cell viability by WST-1 test, apoptosis by TUNEL, lipid peroxidation markers (malondialdehyde, MDA, and 4-hydroxynonenal, HNE) by using assay kits, and biomolecular changes by ATR-FTIR spectroscopy in A549 cells. After zerumbone (0-100 μM) incubation for 24, 48, and 72 h, the number of TUNEL-positive cells was found to be higher in zerumbone-treated cells than in controls, in consistent with cell morphology results. MDA levels increased significantly, although HNE levels increased non-significantly in zerumbone-treated cells. Spectral analyses revealed that the zerumbone-treated groups had higher levels of total saturated and unsaturated lipids as well as comparatively shorter-chain lipids. On the contrary, reduced RNA/DNA ratio, total nucleic acid, and protein content were found in zerumbone-treated groups. Consequently, zerumbone-induced apoptosis was accompanied by increased aldehyde products during lipid peroxidation as well as biomolecular alterations.

This study examines the effects of pulsed wave photobiomodulation (pwPBM) on the osteogenic differentiation of stem cells from the apical papilla (SCAP). Using 810 nm near-infrared (NIR) light with 300 Hz pulses and a 30% duty cycle, pwPBM was applied at a total energy density of 750 mJ/cm². Osteogenesis was evaluated through both in vitro and in vivo analyses. In vitro experiments demonstrated significant enhancement of alkaline phosphatase (ALP) activity, along with upregulation of key osteogenesis-related genes and proteins, as confirmed by real-time polymerase chain reaction (PCR) and Western blot analyses. In vivo, histological assessments following SCAP transplantation revealed increased bone tissue formation, further corroborated by osteocalcin staining. These findings underscore the potential of pwPBM as an innovative and effective tool for dental tissue regeneration and engineering.

The use of photoacoustic brain imaging for hemorrhage detection holds significant clinical importance. This study focuses on the performance of sensitivity and detection capabilities of a single-element scanning system, considering the remarkable signal-to-noise ratio of photoacoustic signals generated by a single-element transducer. By employing blood vessel-like phantoms and ex vivo brain phantoms, we demonstrated the superior efficacy of the single-element scanning method over the transducer array system in the context of brain hemorrhage detection. This research highlights the potential for enhancing hemorrhage detection sensitivity through careful design and optimization of the proposed method, thereby increasing its viability for clinical application.

A challenge in neuroimaging is acquiring frame sequences at high temporal resolution from the largest possible number of pixels. Measuring 1%-10% fluorescence changes normally requires 12-bit or higher bit depth, constraining the frame size allowing imaging in the kHz range. We resolved Ca²⁺ or membrane potential signals from cell populations or single neurons in brain slices by acquiring fluorescence at 8-bit depth and by binning pixels offline, achieving unprecedented frame sizes at kHz rates. In hippocampal slices stained with the Ca²⁺ indicator Fluo-4 AM, we resolved transients at 2 kHz from large frames. Along the apical dendrite of a layer-5 pyramidal neuron, we measured Ca²⁺ signals associated with a back-propagating action potential at 10 kHz. Finally, in the axon initial segment of the same cell type, we recorded an action potential at 40 kHz by voltage-sensitive dye imaging. This approach unlocks the potential for a range of imaging measurements.

Genetic information sensors play a pivotal role in the biomedical field. The detection of deoxyribonucleic acid (DNA) is achieved experimentally using an optical microfiber interferometric sensor, which operates based on an ion-regulation sensitivity enhancement mechanism. The optical microfiber is fabricated by drawing optical fiber into a diameter of less than 10 μm via the melting and tapering technique. Leveraging the characteristics of monovalent cations can effectively promote the folding of G-rich single-stranded DNA (ssDNA) into stable G-quadruplex structures, enabling the detection of specific sequences of ssDNA at low concentrations. The results show an improvement of the linear detection range by 3 orders of magnitude, and with the introduction of the ion-regulation sensitivity enhancement mechanism, the limit of detection (LOD) value is 1.07 × 10^-15 M. This optical microfiber interferometric sensing architecture is characterized by its simplicity and high sensitivity, positioning it as a formidable tool for diverse biosensing and analytical applications.

The article describes a technique for digital holographic reconstruction of complex amplitude fields in diffuse blood facies using laser polarization-interference phase scanning to isolate a single scattered component of the object field. This method serves as the basis for developing algorithms for Mueller-matrix reconstruction of linear and circular birefringence parameters in the polycrystalline architectonics of blood facies. Statistical (central moments of the 1st-4th orders) and multifractal analyses (fractal dimension spectra) are applied to study the optical anisotropy maps of polycrystalline networks during blood dehydration. The study explores a practical application in the differential diagnosis of blood loss volume, identifying higher-order central moments (skewness, kurtosis) as sensitive markers. The method achieved a maximum accuracy of 92.9% in differentiating blood loss volume.

The primary ocular effect of diabetes is diabetic retinopathy (DR), which is associated with diabetic microangiopathy. Diabetic macular edema (DME) can cause vision loss for people with DR. For this reason, deciding on the appropriate treatment and follow-up has a critical role in terms of curing the disease. Current artificial intelligence (AI) approaches focus on OCT images and may ignore clinical, laboratory, and demographic information obtained by the specialist. This study presents a novel deep learning (DL) framework for evaluating the visual outcome of the TREX anti-VEGF intravitreal injection regimen. DL models are trained to extract deep features from OCT and ILM topographic images and the obtained deep features are combined with patients' demographic, clinical, and laboratory findings to predict the direction of the treatment process. When the ResNet-18 network is used, the proposed DL framework is able to predict the prognosis status of patients with the highest accuracy.

Local therapeutic action and targeted drug release are promising approaches compared to traditional systemic drug administration. This is especially relevant for nitric oxide (NO), as its effects change dramatically depending on concentration and cellular context. Materials capable of releasing NO in deep tissues in a controlled manner might open new therapeutic opportunities. Light-sensitive NO donors represent a fascinating class of compounds with significant potential for precise and controlled NO release. However, most of them are sensitive to visible light, with only a few examples absorbing in a near-infrared therapeutic window. Here, we present the proof-of-concept of soft implants consisting of the photon upconverting core and the outer shell loaded with visible-light triggered NO donor. The separation into two compartments results in efficient energy harvesting by the dye and effective NO release under 980 nm infrared irradiation. Such implants could be used in smart therapies implying well-controlled and localized NO release.

We report on the development of a multimodal spectroscopy system, combining diffuse reflectance spectroscopy (DRS) and spatially offset Raman spectroscopy (SORS). A fiber optic probe was designed with spatially offset source-detector fibers to collect subsurface measurements for each modality, as well as ball lens-coupled fibers for superficial measurements. The system acquires DRS, zero-offset Raman spectroscopy (RS) and SORS with good signal-to-noise ratio. Measurements on chicken breast tissue demonstrate that both DRS and RS can acquire spectra from similar depths within tissue. Measurements acquired from the skin of a human volunteer demonstrate distinct Raman peaks at 937 and 1755 cm^-1 that were unique to the zero-offset ball lens configuration and 718 and 1089 cm^-1 for the spatially offset setting. We also identified Raman peaks corresponding to melanin that were prominent in the superficial measurements obtained with the ball lens-coupled fibers but not in the spatially offset fibers.