Journal of Biomedical Optics最新文献

{"title":"Segmentation-guided photon pooling enables robust single-cell analysis and fast fluorescence lifetime imaging microscopy.","authors":"Kayvan Samimi, Danielle E Desa, Xiaotian Zhang, Dan L Pham, Rupsa Datta, Melissa C Skala","doi":"10.1117/1.JBO.31.7.076501","DOIUrl":"10.1117/1.JBO.31.7.076501","url":null,"abstract":"<p><strong>Significance: </strong>Fluorescence lifetime imaging microscopy (FLIM) can probe the metabolic environment of living cells in a label-free and noninvasive manner. However, endogenous fluorophores have low absorption and quantum yields, requiring long integration times to acquire the high photon counts needed for accurate pixel-wise multi-exponential decay fitting.</p><p><strong>Aim: </strong>A computationally light \"region-of-interest\" photon pooling technique was used to expedite label-free, single-cell FLIM acquisition and analysis, and its accuracy was compared with standard fitting techniques.</p><p><strong>Approach: </strong>We first characterized the accuracy and precision of \"region-of-interest\" photon pooling using known fluorescence standards and tested its ability to recover fluorescence lifetimes of single cells and large regions of interest with low photon budgets.</p><p><strong>Results: </strong>Single-cell metabolic information was accurately extracted from scanning periods as low as 1 s, and large FLIM mosaics were acquired 15 times faster than was possible with conventional pixel-level analysis. Lifetimes extracted using photon pooling were comparable to standard measurements requiring much longer integration times. The technique was also applied to measure fluorescence lifetimes in highly dynamic live samples.</p><p><strong>Conclusions: </strong>\"Region-of-interest\" (ROI) photon pooling extracts fluorescence lifetimes from live, dynamic samples with low photon budgets, expediting image acquisition while preserving cell-level or ROI-level lifetime information while sacrificing intra-ROI spatial resolution. The technique is computationally light, does not require machine learning algorithms, and can be integrated with commonly used analysis software and file types.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076501"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13325633/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148375842","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":"Multimodal imaging platform for rapid non-destructive evaluation of pancreatic puncture specimens.","authors":"Jianan Zhang, Qing Zhang, Jiansheng Wang, Chunhua Zhou, Lili Gao, Zhen Sun, Yan Wang, Duowu Zou, Qingli Li","doi":"10.1117/1.JBO.31.7.076502","DOIUrl":"10.1117/1.JBO.31.7.076502","url":null,"abstract":"<p><strong>Significance: </strong>Destructive staining and slow subjective visual inspection remain major limitations in rapid evaluation of biopsy specimens during endoscopic ultrasound-guided fine needle biopsy. Therefore, there is a strong need for a label-free optical imaging approach that enables quantitative specimen assessment while preserving specimen integrity.</p><p><strong>Aim: </strong>A multimodal imaging system integrating hyperspectral and color imaging was developed to acquire images of biopsy specimens without staining or sample preparation.</p><p><strong>Approach: </strong>A hyperspectral on-site evaluation workflow was proposed, integrating hyperspectral imaging and color imaging within a modular platform. Hyperspectral data were analyzed using a support-vector-machine-based segmentation framework for specimen assessment with color images providing reference annotations. No washing or staining is required.</p><p><strong>Results: </strong>Validation on 220 pancreatic biopsy specimens demonstrates accurate non-destructive macroscopic visible core evaluation, achieving an <math><mrow><mi>F</mi> <mn>1</mn></mrow> </math> -score of 94.7%. The proposed workflow improves analysis efficiency by 93% compared with conventional rapid on-site evaluation.</p><p><strong>Conclusions: </strong>We demonstrate that integrating hyperspectral imaging with computational analysis enables rapid, quantitative, and label-free specimen evaluation, highlighting the potential of biomedical optical systems for intra-procedural specimen assessment.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"076502"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13336349/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148436595","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":"Indocyanine green excitation-emission matrix characterization: excitation-dependent emission shifts and application-specific spectra.","authors":"Alberto J Ruiz, Sophie A Lyon, Ethan P M LaRochelle, Kimberley S Samkoe","doi":"10.1117/1.JBO.31.7.077003","DOIUrl":"10.1117/1.JBO.31.7.077003","url":null,"abstract":"<p><strong>Significance: </strong>Indocyanine green (ICG) is the most widely used fluorophore in fluorescence-guided surgery (FGS), and its microenvironment-dependent spectral response is relevant for system design, intersystem comparisons, and phantom development.</p><p><strong>Aim: </strong>To characterize ICG with excitation-emission matrices (EEMs) in the microenvironments of dimethyl sulfoxide (DMSO), bovine serum albumin (BSA) solutions, and 3D-printed (3DP) resin and assess excitation-dependent emission, including red-edge excitation shifts (REES) and departures from Kasha's rule of excitation-independent emission.</p><p><strong>Approach: </strong>EEMs and absorbance spectra were acquired with extracted excitation spectra, emission spectra, emission peaks, centroids, and integrated emission areas under the curves (AUCs). Concentration-dependent behavior was examined in DMSO, and albumin concentration dependence was assessed from 5 to <math><mrow><mn>100</mn> <mtext>  </mtext> <mi>mg</mi> <mo>/</mo> <mi>mL</mi></mrow> </math> . Data processing employed robust local regression to mitigate excitation scattering artifacts.</p><p><strong>Results: </strong>ICG in DMSO exhibited excitation-independent emission consistent with Kasha-Vavilov behavior. By contrast, ICG in BSA solution and 3DP resin displayed excitation-dependent emission with pronounced REES and additional nonlinear departures from Kasha's rule. To our knowledge, this represents the first documentation of REES and broader anti-Kasha effects for ICG or any FGS fluorophore. Within the excitation range most relevant to ICG-FGS ( <math><mrow><mo>∼</mo> <mn>760</mn></mrow> </math> to 805 nm), emission spectra of the BSA solution and 3DP resin overlapped closely, with similar AUC-based comparisons, suggesting that ICG in 3DP resin can serve as a suitable surrogate reference for albumin-bound ICG.</p><p><strong>Conclusions: </strong>The EEM characterization shows that excitation-dependent behavior is a defining feature of ICG in biologically relevant environments, demonstrating that emission cannot be assumed to follow classical Kasha-Vavilov behavior. Reliable comparisons and imaging system design therefore require spectra acquired at defined excitation wavelengths with AUC integration within the emission detection band. Excitation-specific spectra from EEMs establish a consistent framework for intersystem comparisons and phantom standards, whereas the resulting datasets provide a practical spectroscopic reference for addressing excitation-dependent behavior in ICG sensing applications.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"077003"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13416159/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148620226","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":"Sensor-integrated dual-clad fiber probe for OCT-guided retinal endolaser photocoagulation.","authors":"Dongyue Wu, Florian Lux, Max Mai Tobon, Holger Muenz, Soeren Schmidt, Eleonora Tagliabue, Philipp Matten, Çağlar Ataman","doi":"10.1117/1.JBO.31.7.077001","DOIUrl":"10.1117/1.JBO.31.7.077001","url":null,"abstract":"<p><strong>Significance: </strong>Retinal endolaser photocoagulation is a widely performed vitreoretinal procedure but currently lacks real-time intraoperative feedback on treatment outcomes. Integrating optical coherence tomography (OCT) directly into the endolaser probe enables co-localized, intraoperative sensing of tissue response during laser delivery, offering the potential to significantly enhance surgical safety and efficacy.</p><p><strong>Aim: </strong>The aim of the study is to design, fabricate, and demonstrate a fiber-optic smart instrument with a 3D nano-printed microlens and instrument-integrated OCT sensing that enables co-localized, concurrent surgical laser delivery and tomographic sensing of tissue alterations during REPC.</p><p><strong>Approach: </strong>A dual-clad fiber was used to co-axially deliver surgical and OCT beams through the outer multi-mode and inner single-mode cores. A 3D nano-printed aspherical microlens ( <math><mrow><mn>300</mn> <mtext>  </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> diameter) at the fiber tip optimized beam shaping for both lasers in the intravitreal cavity. The optical performance of the 23G instrument-integrated OCT (iiOCT) probe was characterized, and <i>ex vivo</i> validation experiments were conducted on porcine eyes.</p><p><strong>Results: </strong>Optical performance assessments demonstrated close alignment between measured and simulated beam profiles, with an OCT spot size of <math><mrow><mn>37.9</mn> <mtext>  </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> at best focus and a surgical laser beam divergence half-angle of 6.0 deg. The probe demonstrated stable power transmission with a mean deviation of 0.35% across repeated pulses. <i>Ex vivo</i> experiments confirmed co-localized, concurrent surgical laser delivery and OCT sensing of retinal tissue alterations.</p><p><strong>Conclusions: </strong>The miniaturized iiOCT endolaser probe combines surgical laser delivery with OCT sensing, achieving adequate performance for the targeted clinical application. This sensor-integrated instrument has the potential to enable intraocular, intraoperative, and quantitative assessment of treatment outcomes. It could support feedback-driven, robotic endolaser photocoagulation, enhancing the safety and efficacy of retinal endolaser surgery.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"077001"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13371110/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148455963","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":"Enhancing skin tone representation in optical vascular phantoms.","authors":"Anni Ranta-Lassila, Lauri Rannaste, Jarno Petäjä, Marko Korkalainen, Markku Alamäki, Alexey Popov","doi":"10.1117/1.JBO.31.7.075001","DOIUrl":"10.1117/1.JBO.31.7.075001","url":null,"abstract":"<p><strong>Significance: </strong>Racial disparities and bias in the performance of optical medical devices, particularly in individuals with darker skin tones, have raised concerns about diagnostic accuracy and healthcare equity. To address the issue of misdiagnosis in people of color, there is a critical need for more representative tools in device testing and development. Skin-mimicking optical phantoms spanning a broad range of skin tones provide a practical solution, enabling more equitable and accurate evaluation of optical technologies.</p><p><strong>Aim: </strong>We aimed to develop optical skin-mimicking phantoms representing a range of skin tones for use in the development and evaluation of optical medical and consumer wearable devices.</p><p><strong>Approach: </strong>Multi-layered water-free silicone-based optical phantoms were designed and fabricated to replicate the optical and mechanical properties of the skin. A vascular structure was integrated into the phantoms, around which a micropump system was developed to simulate blood flow. The phantoms were evaluated using spectroscopy and hyperspectral imaging.</p><p><strong>Results: </strong>The phantoms of varying skin tones with corresponding individual typology angle values spanning from 51.4 to <math><mrow><mo>-</mo> <mn>7.5</mn> <mtext>  </mtext> <mi>deg</mi></mrow> </math> exhibited optical and mechanical properties comparable to real skin reflectance spectra across different pigmentation levels. Closer spectral agreement with skin was achieved using coffee compared with commercial pigment mixtures. The spectral signature of the blood-mimicking liquid was effectively masked by the darker superficial phantom layer mimicking heavily pigmented epidermis.</p><p><strong>Conclusions: </strong>Optical skin-mimicking phantoms containing vascular structures with various skin tones were demonstrated, showcasing their potential as valuable and durable tools for improving the development of optical medical devices and consumer wearables for diverse populations.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"075001"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13389507/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148562217","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":"Combining label-free Raman spectroscopy with machine learning to monitor COVID-19 disease from acute infection to recovery.","authors":"Maryam Heidarifard, Frédéric Leblond, Frédérick Dallaire, Elsa Brunet-Ratnasingham, Nassim Ksantini, Myriam Mahfoud, Guillaume Sheehy, Hugo Soudeyns, Philippe Jouvet, Sze Man Tse, Caroline Quach, Daniel E Kaufmann, Katherine Ember, Mathieu Dehaes","doi":"10.1117/1.JBO.31.7.077002","DOIUrl":"10.1117/1.JBO.31.7.077002","url":null,"abstract":"<p><strong>Significance: </strong>Monitoring COVID-19 disease from acute infection to recovery is critical to understand biochemical dysregulation and COVID-19 heterogeneity over time.</p><p><strong>Aim: </strong>Our aim is to develop an approach combining label-free Raman spectroscopy and machine learning modeling to enable sensitive biomolecular detection of COVID-19 over time.</p><p><strong>Approach: </strong>Hospitalized patients infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were recruited and stratified based on respiratory support (critical and non-critical). Controls had a negative SARS-CoV-2 test. Blood was collected in the acute and recovery phases and was analyzed with Raman spectroscopy. Four machine learning models based on Raman spectra were developed to differentiate critical and non-critical patients in the acute and recovery phases from controls. For each group of patients, two additional models also classified the patient status (acute versus recovery) using cross-sectional and longitudinal analyses.</p><p><strong>Results: </strong>Raman peaks assigned to proteins, glucose, fatty acids, lactic acid, vitamin A, and lipids were identified in models. Overall, area under the receiver operating characteristic curve values were between 0.83 and 1.00 with sensitivities, specificities, and accuracies between 73% and 100%, 77% and 100%, and 78% and 100%, respectively.</p><p><strong>Conclusions: </strong>These results highlight the capability of combined Raman spectroscopy and machine learning modeling to stratify patients at admission, monitor recovery after discharge, and support strategies to potentially reduce the risk of long-COVID.</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 7","pages":"077002"},"PeriodicalIF":3.3,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13384748/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148603462","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":"Erratum: Color-filter-array-based multispectral photoplethysmography optical sensor and its motion artifact correction algorithm (Erratum).","authors":"Yunfen Wei, Shu Cong, Runchao Yan, Zekai He, Hong Li, Gongming Yu, Mei Zou","doi":"10.1117/1.JBO.31.6.069801","DOIUrl":"10.1117/1.JBO.31.6.069801","url":null,"abstract":"<p><p>[This corrects the article DOI: 10.1117/1.JBO.31.3.037001.].</p>","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"069801"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13255969/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148251639","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":"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":3.3,"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":3.3,"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":"Macrophage volume analysis and real-time monitoring by digital holography.","authors":"Baodan Bai, Yanwei Lu, Geng Zhu, Feiyu Liu, Yubo Liu, Wen Wu, Dezhi Lu, Xiupin Wu","doi":"10.1117/1.JBO.31.6.066002","DOIUrl":"10.1117/1.JBO.31.6.066002","url":null,"abstract":"&lt;p&gt;&lt;strong&gt;Significance: &lt;/strong&gt;Cell volume serves as a macroscopic indicator of cellular metabolism, growth, and signal transduction. Understanding how cell volume varies across macrophage phenotypes is essential for interpreting their functional states and activation processes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Aim: &lt;/strong&gt;We present a label-free, noninvasive method for 3D morphological characterization and volume quantification of macrophages and apply it to monitor volume variations during their biological behaviors.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Approach: &lt;/strong&gt;We employed a home-made off-axis digital holographic microscopy (DHM) system based on a Mach-Zehnder interferometric configuration to reconstruct the 3D morphology of cells. Using the mathematical relationship between the phase map and the cell thickness, we further calculated their cellular volume.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results: &lt;/strong&gt;Our measurements show that M0 macrophages have a nearly spherical morphology with a volume of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;970.54&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;153.15&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mrow&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt; &lt;mrow&gt;&lt;mn&gt;3&lt;/mn&gt;&lt;/mrow&gt; &lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; . &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; macrophages exhibit a flattened, pancake-like morphology with pseudopodia, with a significantly larger volume of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;3822.00&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;437.45&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mi&gt;m&lt;/mi&gt; &lt;mn&gt;3&lt;/mn&gt;&lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; . &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; macrophages present a morphology resembling that of &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; cells but with a volume of &lt;math&gt;&lt;mrow&gt;&lt;mn&gt;2743.10&lt;/mn&gt; &lt;mo&gt;±&lt;/mo&gt; &lt;mn&gt;254.67&lt;/mn&gt; &lt;mtext&gt;  &lt;/mtext&gt; &lt;mi&gt;μ&lt;/mi&gt; &lt;msup&gt;&lt;mi&gt;m&lt;/mi&gt; &lt;mn&gt;3&lt;/mn&gt;&lt;/msup&gt; &lt;/mrow&gt; &lt;/math&gt; . It indicates that the cell volume might be a potential parameter to distinguish different polarized macrophages. In addition, we successfully monitored the volume changes of macrophages during cell death, cell division, and the polarization process from &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; to &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; . The cell-death process behaved as expected, with the cell volume continuously decreasing and eventually reaching a plateau. The division event we observed occurred together with cell death; during division, the total volume of the cell cluster increased sharply and then gradually decreased as cell death progressed. During the 8-h &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; -to- &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;1&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; polarization process, two phases of gradual volume increase and two phases of rapid volume increase were observed. In the early stage (0 to 2 h), &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt; &lt;/math&gt; macrophages were likely not fully activated, showing only mild volume changes but still exhibiting an increasing trend. At 6 to 8 h, the cells undergo a sharp increase in volume, reflecting their full activation and transition toward the &lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt; &lt;m","PeriodicalId":15264,"journal":{"name":"Journal of Biomedical Optics","volume":"31 6","pages":"066002"},"PeriodicalIF":3.3,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13233025/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148163323","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}