Journal of Biomedical Optics最新文献

{"title":"3D-motion mapping of the malleus-incus complex using a robot-mounted optical coherence tomography vibrometry system.","authors":"Nathan Goedseels, Pieter Livens, Yang Li, Guy Fierens, Nicolas Verhaert, Tristan Putzeys","doi":"10.1117/1.JBO.31.12.123303","DOIUrl":"10.1117/1.JBO.31.12.123303","url":null,"abstract":"<p><strong>Significance: </strong>Optical coherence tomography vibrometry (OCTv) allows measuring the surface and subsurface nanometer vibrations of the mammalian ossicular chain. However, existing multidimensional OCTv setups remain expensive, complex, or limited in accuracy.</p><p><strong>Aim: </strong>We developed a 3D OCTv setup with a rotational component and provided a theoretical framework that clarifies the main determinants of measurement accuracy in 3D vibrometry.</p><p><strong>Approach: </strong>A commercially available OCTv system is mounted on a robotic arm to allow multidimensional measurements. The relative positions of measured structures and the optical axes orientation are defined with a custom volume registration algorithm.</p><p><strong>Results: </strong>We present a mathematical framework for decomposing the measured motion components into a Cartesian space and identify key factors that influence the decomposition accuracy. The angular accuracy of optical axis estimation was 0.4 deg. Experimental validation was performed on an oscillating phantom and on the malleus-incus complex (MIC) of a fresh human temporal bone specimen, replicating previous evidence on the MIC's frequency-dependent vibratory behavior.</p><p><strong>Conclusions: </strong>The robot-mounted 3D OCTv setup provides a cost-effective, robust, and integral solution for mapping middle ear 3D vibrations, accurately orienting optical axes across measurements. Future work should integrally map the ossicular chain to test the commonly assumed rigid-body behavior of ossicular motion.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 12","pages":"123303"},"PeriodicalIF":2.9,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12935278/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147306155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Robot-assisted minimally invasive photoacoustic imaging for monitoring liver ablation using diffusing fiber illumination.","authors":"Shang Gao, Xihan Ma, Yanbo Hua, Sharath Bhagavatula, Guigen Liu, Oliver Jonas, Haichong K Zhang","doi":"10.1117/1.JBO.31.12.123302","DOIUrl":"https://doi.org/10.1117/1.JBO.31.12.123302","url":null,"abstract":"<p><strong>Significance: </strong>Accurate intraoperative assessment of ablation completeness in liver radiofrequency ablation (RFA) remains a clinical challenge, as conventional imaging lacks real-time capability to delineate necrotic boundaries. Incomplete ablation increases recurrence risk, underscoring the need for real-time, high-resolution imaging with functional tissue differentiation.</p><p><strong>Aim: </strong>We propose a robot-assisted photoacoustic (PA) imaging system employing a customized diffusing optical fiber to improve intraoperative monitoring of liver RFA.</p><p><strong>Approach: </strong>The system integrates circumferential wide-field illumination for enhanced tissue coverage with robotic automated 3D scanning and co-registered ultrasound. Spectroscopic PA imaging differentiates necrotic from viable tissue based on optical absorption, whereas a standard Hough transform algorithm suppresses fiber-induced artifacts. Validation was performed using <i>ex vivo</i> and cadaveric swine liver studies.</p><p><strong>Results: </strong>In cadaveric studies, 3D lesion mapping showed necrotic zones of <math><mrow><mn>7.55</mn> <mo>×</mo> <mn>5.37</mn> <mo>×</mo> <mn>7.42</mn> <mtext>  </mtext> <mi>mm</mi></mrow> </math> , closely matching gross pathology measurements (7.93 mm average diameter), confirming system accuracy.</p><p><strong>Conclusions: </strong>The proposed system enables accurate, real-time visualization of ablation lesions <i>in situ</i>, offering a clinically viable approach to improve treatment precision and reduce recurrence in liver RFA procedures.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 12","pages":"123302"},"PeriodicalIF":2.9,"publicationDate":"2026-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12921445/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147270943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of solid-state fluorescence lifetime standards for clinical applications using dyed epoxy resins.","authors":"Dario Angelone, Keela Hughes, Hasti Yavari, Sara Eugenia Garduño Gómez, Brian C Wilson, Stefan Andersson-Engels, Katarzyna Komolibus, Sanathana Konugolu Venkata Sekar","doi":"10.1117/1.JBO.31.11.113503","DOIUrl":"10.1117/1.JBO.31.11.113503","url":null,"abstract":"<p><strong>Significance: </strong>Fluorescence lifetime imaging (FLIm) offers label-free contrast based on intrinsic tissue properties, making it a promising tool for clinical diagnostics and intraoperative guidance. However, the lack of robust, reproducible standards for system validation limits cross-platform comparability, impedes quality assurance, and hinders clinical translation.</p><p><strong>Aim: </strong>We aim to develop and characterize a set of stable solid-state fluorescence lifetime (FLT) standards using dyed epoxy resins, with the goal of enabling reliable calibration, benchmarking, and validation of FLIm systems in both research and clinical environments.</p><p><strong>Approach: </strong>A series of solid standards incorporating different dyes were fabricated to span a range of lifetimes from sub-nanosecond to over 3.5 ns. These materials were evaluated for FLT, emission intensity, photostability under UV exposure, and fabrication repeatability. The influence of dye concentration and microstructural uniformity was assessed using a confocal microscope. The standards were also applied to validate a chip-on-tip FLIm micro-camera designed for endoscopic imaging.</p><p><strong>Results: </strong>The dyed epoxy standards demonstrated consistent and reproducible lifetimes, good photostability, and scalable fabrication. Confocal imaging revealed some microstructural heterogeneity, whereas bulk measurements remained robust. The standards enabled effective validation of the FLIm micro-camera, including spatial and temporal resolution assessment, and highlighted platform-dependent biases in lifetime estimation.</p><p><strong>Conclusions: </strong>Dyed epoxy materials show strong potential as practical, scalable tools for FLIm system calibration and quality assurance. These standards may support cross-platform validation and benchmarking of emerging FLIm technologies and could contribute to the development of future regulatory frameworks for clinical adoption.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 11","pages":"113503"},"PeriodicalIF":2.9,"publicationDate":"2026-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13012335/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147512328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superconducting nanowire single-photon detectors for enhanced biomedical imaging.","authors":"Emi Cora Valmai Hughes, Avinash Upadhya, Kishan Dholakia","doi":"10.1117/1.JBO.31.11.113502","DOIUrl":"10.1117/1.JBO.31.11.113502","url":null,"abstract":"<p><strong>Significance: </strong>Superconducting nanowire single-photon detectors (SNSPDs; also known as SSPDs) show enormous promise for low-light biomedical imaging by offering exceptional sensitivity, picosecond timing resolution, and broad spectral coverage.</p><p><strong>Aim: </strong>This perspective evaluates the role of SNSPDs by comparing their performance with other photon-counting detectors for emerging biomedical imaging applications.</p><p><strong>Approach: </strong>We describe the need for ultrasensitive detectors for biophotonics, summarize SNSPD operating principles, and compare their performance with established photon-counting devices. We highlight applications where SNSPDs make previously unattainable imaging capabilities possible and discuss system-level challenges and technological developments that are critical to future applications, including clinical translation.</p><p><strong>Results: </strong>SNSPDs offer advantages in signal-to-noise ratio, temporal precision, and detection bandwidth, enabling deep tissue imaging, high-precision fluorescence lifetime measurements, and quantum-enhanced imaging modalities. Advances in scalable arrays, cryogenic miniaturization, and improved signal collection are reducing barriers to widespread adoption.</p><p><strong>Conclusions: </strong>SNSPDs are poised to transform photon-limited biomedical imaging. As device performance and system integration continue to advance, their adoption in imaging platforms is expected to accelerate. Combining SNSPDs with advancements in the excitation pathway, such as structured-light excitation with Bessel beams, aberration correction, and wavefront shaping, shows promise for delivering unprecedented imaging capabilities and broadening both the preclinical and clinical utility of these detectors.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 11","pages":"113502"},"PeriodicalIF":2.9,"publicationDate":"2026-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13012184/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147512268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Roadmap for light interaction with biophotonic surfaces and their diverse applications.","authors":"Adam Władziński, Igor Meglinski, Alexander Bykov, Maria Gritsevich, Mikhail Kryuchkov, Vladimir L Katanaev, Brindusa Dragoi, Nicolina Pop, Junyoung Kwon, Susete N Fernandes, Maria Helena Godinho, Savvas G Chalkidis, Georgios C Vougioukalakis, Atle M Bones, Maciej S Wróbel, Katarzyna Karpienko, Marta Władzińska, Patryk Sokołowski, Tatiana Novikova, Jessica C Ramella-Roman, Jošt Stergar, Urban Simončič, Matija Milanič, Nikola Vuković, Jelena Radovanović, Aleksandar Demić, Dragan Inđjin, Marcin Gnyba, Małgorzata Szczerska","doi":"10.1117/1.JBO.31.6.064302","DOIUrl":"https://doi.org/10.1117/1.JBO.31.6.064302","url":null,"abstract":"<p><strong>Significance: </strong>Biophotonics has advanced through many discoveries, yet challenges remain, including label-free biomolecular specificity, quantitative imaging, and single-molecule detection. Progress is further constrained by the need for cheaper, lighter, miniaturized materials that still meet strict optical, electrical, and mechanical specifications. This limitation can be overcome if bioinspired structures are developed. One of the developed areas in which solutions in nature are used is micro and nanostructures including nanosurfaces. It offers a way to increase biomolecular specificity and develop lightweight, low-cost devices for biomedicine. However, it requires measuring phenomena in materials and testing these materials in applications, e.g., sensing systems.</p><p><strong>Aim: </strong>We offer a concise, authoritative overview of biophotonics-from nanoscale light-biomolecule interactions to bioinspired materials, phantoms, test methods, and sensor development.</p><p><strong>Approach: </strong>A coherent and comprehensive analysis of the crucial problems related to the development of bioinspired materials and devices was carried out. Recent advances in light scattering by biological surfaces enable structure characterization, disease diagnosis, red-blood-cell analysis, drug discovery, and optical imaging and sensing. Structural and genetic bases of biological photonic surfaces were examined, alongside key performance factors in bio-inspired materials-biocompatibility, biodegradability, structure-optics coupling (e.g., dynamic color change), and scalability limits. We survey chiral nanomaterials, silica frustules, and artificial surfaces that emulate peacock feathers, butterfly wings, iridescent fruits, plant petals, and beetle cuticles, highlighting complementary diagnostics-omics, hyperspectral, and terahertz imaging-for structural analysis and material innovation. We examine bio-inspired phantoms for medical calibration, recent advances in Monte Carlo tissue light-transport modeling, and the resulting applications of these materials and diagnostic tools.</p><p><strong>Results: </strong>Results confirm a broad set of tunable bio-inspired materials: key optical phenomena were mapped, structures fabricated and modeled, phantoms validated, and strong sensor potential demonstrated.</p><p><strong>Conclusions: </strong>We survey emerging biophotonics, review material and system requirements, and emphasize simplifying and miniaturizing sensors for biomedical use.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"064302"},"PeriodicalIF":2.9,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12911917/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146219793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polarizer-assisted pupillometry through closed eyelids, overcoming pupil position dependence.","authors":"Michal Tepper, Omer Ben Barak-Dror, David Haggiag, Israel Gannot, Yuval Nir","doi":"10.1117/1.JBO.31.6.064303","DOIUrl":"10.1117/1.JBO.31.6.064303","url":null,"abstract":"<p><strong>Significance: </strong>Accurate monitoring of pupil size and gaze direction is critical in clinical and research contexts; however, current pupillometry methods require open eyes, limiting their use in patients under anesthesia, sedation, or sleep. Short-wave infrared (SWIR) imaging enables noninvasive closed-eye pupillometry, but challenges remain due to eyelid glare, gaze variability, and low signal-to-noise ratio (SNR).</p><p><strong>Aim: </strong>We aimed to enhance closed-eye pupillometry by integrating polarization filters into the SWIR imaging system and developing improved algorithms for pupil localization and gaze direction estimation under natural closed-eye conditions.</p><p><strong>Approach: </strong>Experiments were conducted on healthy volunteers using SWIR imaging with different polarizer configurations (parallel, partially crossed, crossed, and no polarizers). Pupillary light reflexes (PLR) were recorded under open- and closed-eye conditions with both forward fixation and varying gaze directions. Image analysis incorporated brightness difference imaging and statistical modeling to evaluate maximal brightness change and SNR.</p><p><strong>Results: </strong>In open-eye settings, parallel polarizers produced the strongest PLR signal, but in closed-eye conditions, crossed polarizers significantly improved image quality by suppressing eyelid glare. The crossed configuration yielded the highest PLR brightness change and SNR compared with parallel or no polarizers, enabling reliable pupil localization across multiple gaze directions. Improved algorithms allowed robust PLR detection even under natural eyelid closure and variable gaze positions.</p><p><strong>Conclusions: </strong>Integrating crossed polarizers into SWIR-based pupillometry substantially enhances signal fidelity and pupil localization through closed eyelids. This approach overcomes major limitations of previous methods and enables accurate, touchless pupillometry in clinically relevant conditions. These advances pave the way for applications in anesthesiology, sleep medicine, and neurocritical care.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"064303"},"PeriodicalIF":2.9,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12900575/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146201864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Endoscopic iso-pathlength self-calibration for direction-resolved retrieval of tissue optical properties.","authors":"Natanel Ovadia, Hamootal Duadi, Dror Fixler","doi":"10.1117/1.JBO.31.6.064305","DOIUrl":"https://doi.org/10.1117/1.JBO.31.6.064305","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Significance: &lt;/strong&gt;Medical examination of human tissue is preferably performed by imaging the tissue surface. Optical imaging techniques are limited by low penetration depth due to high tissue scattering, whereas sensing techniques can detect changes deeper inside the tissue. Near-infrared sensing methods such as oximetry and fNIRS are already used clinically but have not yet been applied in endoscopy.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim: &lt;/strong&gt;We investigate the existence of iso-pathlength (IPL) points in endoscopic geometry, with the goal of extending the concept of IPL points from cylindrical and half-infinite geometries into hollow cylindrical tissue relevant to endoscopy. In addition, we demonstrate the ability to extract the absorption properties of a tissue at this structure by the IPL and demonstrate it by &lt;i&gt;ex vivo&lt;/i&gt; experiment.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach: &lt;/strong&gt;The IPL point is a unique position in the full scattering profile, independent of tissue scattering and dependent only on the tissue absorption and geometry. We studied two directions in cylindrical endoscopic geometry: azimuthal and longitudinal. First, diffusion theory with extrapolated zero-boundary conditions was applied to predict IPL positions. These predictions were then tested using Monte Carlo simulations of photon distribution and validated experimentally using phantoms with cylindrical air holes measured by endoscopy. Finally, using the experimentally identified IPL point and applying the same procedure to a standard phantom, a hemoglobin-agar phantom, and chicken breast tissue, we were able to estimate the absorption coefficient of the chicken tissue.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Both azimuthal and longitudinal IPL points were identified. The experimental azimuthal IPL point was found at an angle of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;144&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;deg&lt;/mi&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;3&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;deg&lt;/mi&gt;&lt;/mrow&gt; &lt;/math&gt; , whereas the longitudinal IPL point appeared at a distance of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0.33&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;0.05&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;/math&gt; from the laser spot center. These findings confirm the theoretical and simulation predictions. Moreover, from the &lt;i&gt;ex vivo&lt;/i&gt; experiment of a chicken breast, the IPL point enables us to calculate the absorption coefficient and get &lt;math&gt; &lt;mrow&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mtext&gt;a&lt;/mtext&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;mo&gt;=&lt;/mo&gt; &lt;mn&gt;0.94&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; , within the range of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;0.2&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;mo&gt;≤&lt;/mo&gt; &lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mtext&gt;a&lt;/mtext&gt;&lt;/mrow&gt; &lt;/msub&gt; &lt;mo&gt;≤&lt;/mo&gt; &lt;mn&gt;2&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;cm&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mo&gt;-&lt;/mo&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; .&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;The demonstration of IPL points in endoscopic geometry provides a ne","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"064305"},"PeriodicalIF":2.9,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13005598/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147498756","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"DNA-hybridization on gold nanospheres: a dual-fluorescence investigation of surface loading and strand length effects.","authors":"Daria Stoia, Ana-Maria Craciun, Gabriela Chereches, Olga Soritau, Dana Maniu, Simion Astilean, Marc Lamy de la Chapelle, Monica Focsan","doi":"10.1117/1.JBO.31.6.064304","DOIUrl":"10.1117/1.JBO.31.6.064304","url":null,"abstract":"<p><strong>Significance: </strong>Gold nanospheres (AuNSs) functionalized with DNA are powerful tools for studying nanoscale biomolecular interactions through fluorescence modulation. Understanding how DNA conformation influences fluorescence is essential for advancing biosensor design.</p><p><strong>Aim: </strong>We examine how DNA strand length and surface loading govern the fluorescence behavior of Cy5-labeled single-stranded DNA (polyA-Cy5) bound to AuNSs and how these properties change upon hybridization with complementary polyT strands.</p><p><strong>Approach: </strong>PolyA-Cy5 strands of different bases were conjugated to AuNSs and analyzed using steady-state and time-resolved fluorescence spectroscopy before and after polyT hybridization.</p><p><strong>Results: </strong>Surface attachment induced strong fluorescence quenching, with intensity varying with strand length due to differences in DNA conformation. Short strands remained rigid and upright, whereas longer strands adopted more flexible geometries. Upon hybridization, longer duplexes exhibited fluorescence enhancement attributed to increased fluorophore-metal spacing as dsDNA becomes more upright. Lifetime measurements supported these conformational changes and suggest a Förster resonance energy transfer (FRET)-based quenching mechanism. Experiments in fetal bovine serum (FBS) confirmed that hybridization-induced enhancement persists in biologically relevant media.</p><p><strong>Conclusions: </strong>The results reveal strand-length and density-dependent conformational dynamics of DNA on AuNSs and establish a robust fluorescence-based method for probing nanoscale assembly. The nanosystem can also be tracked intracellularly, as demonstrated by its detectable signal in fluorescence imaging.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"064304"},"PeriodicalIF":2.9,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12949946/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147344241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing small-animal molecular imaging through multifaceted innovation.","authors":"Guosong Hong, Chongzhao Ran, Scott C Davis, Kenneth M Tichauer","doi":"10.1117/1.JBO.31.5.054701","DOIUrl":"10.1117/1.JBO.31.5.054701","url":null,"abstract":"<p><p>The editorial highlights articles in a JBO special section, as well as emerging trends in small-animal molecular imaging.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 5","pages":"054701"},"PeriodicalIF":2.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13133712/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147814842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corneal dose response from exposure to a <i>Q</i>-switched laser at a central wavelength of 1645 nm using a rabbit model.","authors":"Joseph J Chue-Sang, Xomalin G Peralta, Joseph E Clary, Andrea Smith, Amanda Peterson, Matthew E Macasadia, Amanda J Tijerina, Gary D Noojin, Maximillian V Hart, Charles F Schwarten, Wesley T Kinerk, Lyndsey M Ferris, Emily N Boice","doi":"10.1117/1.JBO.31.5.054703","DOIUrl":"10.1117/1.JBO.31.5.054703","url":null,"abstract":"<p><strong>Significance: </strong>Laser safety studies of the eye are well documented for visible wavelength and continuous wave lasers. There are fewer experimental results for infrared wavelengths and pulsed lasers.</p><p><strong>Aim: </strong>We aim to fill the gap at 1645 nm for single nanosecond pulse duration exposures of rabbit cornea and determine the threshold radiant exposure to generate lesions 50% of the time (estimated dose <math> <mrow><msub><mi>ED</mi> <mn>50</mn></msub> </mrow> </math> ).</p><p><strong>Approach: </strong>Images of the cornea during exposures were acquired using slit lamp microscopy and optical coherence tomography. A histological analysis helped provide dosimetry relationships with morphology and mechanisms of the damage.</p><p><strong>Results: </strong>We measured the energy <math> <mrow><msub><mi>ED</mi> <mn>50</mn></msub> </mrow> </math> value at <math><mrow><mn>3.86</mn> <mo>±</mo> <mn>0.085</mn> <mtext>  </mtext> <mi>mJ</mi></mrow> </math> utilizing the slit lamp biomicroscopy. Incorporating the experimental spot size diameter, this corresponds to a peak radiant exposure of <math><mrow><mn>102</mn> <mtext>  </mtext> <mi>J</mi> <mo>/</mo> <msup><mrow><mi>cm</mi></mrow> <mrow><mn>2</mn></mrow> </msup> </mrow> </math> . By contrast, the average radiant exposure <math> <mrow><msub><mi>ED</mi> <mn>50</mn></msub> </mrow> </math> over a 1-mm diameter limiting aperture as per the ANSI Z.136 convention was <math><mrow><mn>0.49</mn> <mtext>  </mtext> <mi>J</mi> <mo>/</mo> <msup><mrow><mi>cm</mi></mrow> <mrow><mn>2</mn></mrow> </msup> </mrow> </math> . Additional analysis via optical coherence tomography (OCT) and histology examined the severity and degree of damage.</p><p><strong>Conclusion: </strong>This experimental approach performed well to characterize damage and identify damage thresholds to inform the laser safety standard community of the accuracy of current exposure limits.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 5","pages":"054703"},"PeriodicalIF":2.9,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12893126/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146179678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}