Journal of Biophotonics最新文献

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.

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.

Breast augmentations, commonly performed for aesthetic or medical reasons, often use silicone (polydimethylsiloxane [PDMS]) implants. Some patients develop complications like capsular contracture, where scar tissue forms around the implant. Previously, we used stimulated Raman scattering (SRS) microscopy to detect and quantify silicone in stained capsule tissue, finding a correlation between silicone amount and contracture severity. However, we suspected silicone loss during histological preparation, which includes multiple steps like formalin fixation and paraffin embedding. In this study, we assessed silicone loss by comparing adjacent tissue samples from the same capsule: one prepared conventionally and the other snap-frozen. SRS microscopy revealed that snap-frozen samples had roughly five times more silicone, indicating significant silicone loss during conventional preparation. Thus, measuring silicone in histologically prepared samples likely underestimates PDMS content.

We report here on the development of tailored plasmonic AgNPs/C:H:N:O plasma polymer nanocomposites for the detection of the pathogenic bacterium Borrelia afzelii , with high selectivity and sensitivity. Silver (Ag) nanoparticles, generated by a gas aggregation source, are incorporated onto a C:H:N:O plasma polymer matrix, which is deposited by magnetron sputtering of a nylon 6.6. These anchored Ag nanoparticles propagate localized surface plasmon resonance (LSPR), optically responding to changes caused by immobilized pathogens near the nanoparticles. The tailored functionalization of AgNPs/C:H:N:O nanocomposite surface allows both high selectivity for the pathogen and high sensitivity with an LSPR red-shift Δλ > (4.20 ± 0.71) nm for 50 Borrelia per area 0.785 cm². The results confirmed the ability of LSPR modulation for the rapid and early detection of (not only) tested pathogens.

Fluorescence-guided surgeries, including tumor resection and tissue soldering, are advancing the frontiers of surgical precision by offering enhanced control that minimizes tissue damage, improving recovery and outcomes. However, integrating fluorescence visualization with real-time temperature monitoring remains a challenge, limiting broader clinical use. We address this issue with an augmented reality (AR) visor that combines nanomaterial excitation, fluorescence detection, and temperature monitoring. Using advanced fluorescent nanoparticles like indocyanine green-doped particles and carbon nanotubes, the visor provides a comprehensive view of both the surgical field and sub-surface conditions invisible to the naked eye. This integration improves the safety and efficacy of fluorescence-guided surgeries, including laser tissue soldering, by ensuring optimal temperatures and laser guidance in real time. The presented technology enhances existing surgical techniques and supports the development of new strategies and sensing technologies in areas where traditional methods fall short, marking significant progress in precision surgery and potentially improving patient care.