Biophotonics discovery最新文献

{"title":"Use of imaging technologies to support complex generic drug development.","authors":"Priyanka Ghosh, Elizabeth Bielski, Andre O'Reilly Beringhs, Bin Qin, Markham C Luke, Sam G Raney","doi":"10.1117/1.BIOS.3.4.043106","DOIUrl":"10.1117/1.BIOS.3.4.043106","url":null,"abstract":"<p><strong>Significance: </strong>Complex drug products remain costly and inaccessible to many patients. The use of modern imaging technologies offers transformative tools to address generic drug research challenges, allowing for improved patient access to safe and effective generic medicines.</p><p><strong>Aim: </strong>This review summarizes imaging research related to a wide range of complex drug products across five coordinated initiatives: high-order characterization of the arrangement of matter in complex products; elucidation of the relationship between the structural features and the functional performance of these dosage forms; establishment of noninvasive approaches to characterize and compare the rate and extent of drug bioavailability from these dosage forms; development of reliable artificial intelligence and machine learning approaches to analyze imaging data; and provision of mechanistic insights to inform the construction of computational models.</p><p><strong>Results and conclusions: </strong>The technologies summarized in this work enabled non-destructive structural characterization of complex drug products, establishment of structure-performance relationships, and direct measurement of drug availability at local sites of action. Furthermore, currently available technologies used for imaging complex drug products continue to support the establishment of scientifically rigorous, efficient bioequivalence pathways for complex generic products, reducing reliance on costly comparative clinical endpoint studies.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 4","pages":"043106"},"PeriodicalIF":0.0,"publicationDate":"2026-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13669564/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149217721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Commercialization report: SpectraWAVE Inc.","authors":"Eman Namati","doi":"10.1117/1.BIOS.3.3.030501","DOIUrl":"https://doi.org/10.1117/1.BIOS.3.3.030501","url":null,"abstract":"<p><p>This community report discusses the experience of navigating the complex path of commercializing biomedical technologies, offering lessons for the scientific community and industry stakeholders alike.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"030501"},"PeriodicalIF":0.0,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13625631/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149122538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Label-free 4D holotomography with depth-adaptive segmentation for quantitative analysis of lipid droplet dynamics in hepatic organoids.","authors":"Jimin Cho, Hoyeon Lee, ChulMin Oh, Juyeon Park, Sujin Park, Bon-Kyoung Koo, YongKeun Park","doi":"10.1117/1.BIOS.3.3.035005","DOIUrl":"https://doi.org/10.1117/1.BIOS.3.3.035005","url":null,"abstract":"<p><strong>Significance: </strong>Quantifying lipid droplet (LD) remodeling in 3D hepatic organoids is often limited to endpoint staining or phototoxic live fluorescence imaging, thereby obscuring droplet-level kinetics.</p><p><strong>Aim: </strong>We aimed to develop a label-free method to track LD dynamics in living hepatic organoids under different fatty-acid loads.</p><p><strong>Approach: </strong>Time-lapse 3D refractive-index tomograms were acquired using holotomography and analyzed with a depth-adaptive, multithreshold segmentation pipeline to quantify LD number, volume, sphericity, and refractive-index-derived concentration and dry mass at single-droplet resolution.</p><p><strong>Results: </strong>Oleic acid and linoleic acid induced LD accumulation while preserving organoid integrity, whereas palmitic acid triggered rapid structural collapse. Despite increases in total LD burden under both oleic acid and linoleic acid, droplet-level dynamics diverged: oleic acid produced volume-dominated accumulation via enlargement of fewer LDs and increased size heterogeneity, whereas linoleic acid produced number-dominated accumulation via sustained increases in LD number, yielding a more uniform population of small droplets.</p><p><strong>Conclusions: </strong>Label-free holotomography with depth-adaptive analysis enables noninvasive, longitudinal, and multiscale quantification of LD dynamics in intact organoids and reveals fatty-acid-dependent temporal modes of lipid storage.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"035005"},"PeriodicalIF":0.0,"publicationDate":"2026-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13624778/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149122522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Feasibility of label-free multiphoton luminescence imaging to track the fate of inhaled gold nanoparticles in <i>ex vivo</i> lung tissue.","authors":"Sean Burkitt, Olga Eremina, Alexander Czaja, Boyi Wang, William Wallace, Cristina Zavaleta","doi":"10.1117/1.BIOS.3.4.043105","DOIUrl":"10.1117/1.BIOS.3.4.043105","url":null,"abstract":"<p><strong>Significance: </strong>Understanding the biological journey of inhaled gold nanomaterials is critical for nanotoxicology and therapeutic delivery. Conventional tracking methods often require fluorescent labeling, which can alter nanoparticle (NP) surface chemistry and lead to \"false-positive\" signals if the label dissociates.</p><p><strong>Aim: </strong>In this feasibility study, we utilize multiphoton luminescence (MPL) imaging to track the long-term biodistribution of 50 nm AuNPs following inhalation exposure at 1 week and 1 month.</p><p><strong>Approach: </strong>Mice were administered AuNPs via intranasal inhalation in four experimental groups: low (0.1 nM), medium (1 nM), high (10 nM) doses for 1 week, and a medium dose (1 nM) for 1 month. Organs were harvested and analyzed using ICP-MS for total gold content and MPL imaging for label-free visualization of AuNP deposition.</p><p><strong>Results: </strong>AuNPs remained localized within the lungs with no evidence of systemic translocation to the liver, spleen, brain, or kidneys at either time point. MPL imaging revealed that lung concentration followed a linear scaling model at one week. MPL imaging also revealed the long-term identification and localization of AuNPs within the lung at 1 month postinhalation.</p><p><strong>Conclusions: </strong>MPL imaging is superior to brightfield microscopy for NP detection, enabling the visualization of dose-dependent aggregation and deep-tissue mapping. These findings demonstrate the feasibility of MPL imaging as a label-free complementary imaging approach for pulmonary nanoparticle biodistribution studies.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 4","pages":"043105"},"PeriodicalIF":0.0,"publicationDate":"2026-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13622989/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149083345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning approach for enumeration of circulating cells with diffuse <i>in vivo</i> flow cytometry.","authors":"Mehrnoosh Emamifar, Jane Lee, Malcolm Shumel, Joshua Pace, Chiara Bellini, Mark Niedre","doi":"10.1117/1.BIOS.3.3.032903","DOIUrl":"10.1117/1.BIOS.3.3.032903","url":null,"abstract":"<p><strong>Significance: </strong>Diffuse <i>in vivo</i> flow cytometry (DiFC) is an emerging technique for enumerating rare, fluorescently labeled circulating tumor cells (CTCs) in small animals without drawing blood samples. DiFC uses detection of transient fluorescent peaks in time-series data. Previously, we used a simple amplitude threshold-based method for identifying peak candidates, but this ignored potentially useful information in peak shape that could reduce false-positive detections and increase detection efficiency of lower-amplitude peaks.</p><p><strong>Aim: </strong>Our aim is to develop a machine learning (ML)-integrated signal processing approach for DiFC that improves CTC enumeration by better discriminating CTC peaks from artifacts.</p><p><strong>Approach: </strong>We developed an ML-integrated approach that incorporates a convolutional neural network (CNN) classifier. The CNN was trained to distinguish CTC peaks from artifacts by analyzing peak amplitude and temporal shape characteristics. Performance was evaluated on <i>in silico</i>, control, and CTC-bearing mouse datasets.</p><p><strong>Results: </strong>The CNN classifier achieved accuracy, precision, sensitivity, and specificity exceeding 94% on test data. Compared with our previously published threshold-based approach, the ML-integrated method increased the number of correctly identified CTCs and their flow direction while reducing false detections across evaluation datasets.</p><p><strong>Conclusions: </strong>The ML-integrated approach substantially improves DiFC CTC enumeration, enabling robustness against artifacts in noisy conditions.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"032903"},"PeriodicalIF":0.0,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557453/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Autofluorescence lifetime imaging resolves cell heterogeneity within peripheral blood mononuclear cells.","authors":"Jeremiah M Riendeau, Lucia Hockerman, Elizabeth Maly, Kayvan Samimi, Melissa C Skala","doi":"10.1117/1.BIOS.3.3.035003","DOIUrl":"10.1117/1.BIOS.3.3.035003","url":null,"abstract":"<p><strong>Significance: </strong>Standard methods to characterize peripheral blood mononuclear cells (PBMCs) are often destructive, lack metabolic information, or do not provide single-cell resolution. Label-free tools that nondestructively measure single-cell metabolism within PBMCs can provide new layers of information to characterize disease state and cell therapy potential.</p><p><strong>Aim: </strong>We aim to determine whether nondestructive fluorescence lifetime imaging microscopy (FLIM) of the endogenous metabolic cofactors nicotinamide adenine dinucleotide (phosphate) (reduced form) and flavin adenine dinucleotide (oxidized form), or optical metabolic imaging (OMI), can identify immune cell subsets and activation state within heterogeneous PBMC cultures.</p><p><strong>Approach: </strong>OMI measured single-cell metabolism of PBMCs from three different human donors in the quiescent or activated (phorbol 12-myristate 13-acetate and ionomycin) state. Fluorescent antibodies were used as ground truth labels for single-cell classifiers of immune cell subtypes.</p><p><strong>Results: </strong>OMI identified quiescent versus activated PBMCs with 94% accuracy at only 2 h post-stimulation, identified monocytes within quiescent and activated PBMCs with 96% and 88% recall, respectively, and identified NK cells within quiescent and activated PBMCs with 74% recall.</p><p><strong>Conclusion: </strong>OMI identifies activation state and immune cell subpopulations within PBMCs, enabling single-cell and label-free measurements of metabolic heterogeneity within complex PBMC samples. Therefore, OMI could enhance PBMC immunophenotyping for diagnostic and therapeutic applications.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"035003"},"PeriodicalIF":0.0,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557457/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Single-fiber co-registered Raman-OCT technique with deep learning enhances <i>in vivo</i> oral tissue assessment.","authors":"Chang Liu, Bin He, Kan Lin, Chi Shu, Wei Zheng, Zhiwei Huang","doi":"10.1117/1.BIOS.3.3.035004","DOIUrl":"10.1117/1.BIOS.3.3.035004","url":null,"abstract":"<p><p>Conventional oral cancer diagnosis relies on white light imaging and tissue biopsy that fail to capture critical microstructural and biomolecular information, thereby limiting early detection of precancerous and malignant lesions. To address these challenges, we present a unique coaxial and co-registered morpho-chemical imaging platform that integrates Raman spectroscopy (RS) and optical coherence tomography (OCT) within a compact, single-fiber probe. This integration uniquely enables video-rate OCT imaging together with sub-second Raman acquisition, providing spatially aligned microstructural and biochemical tissue information <i>in vivo</i>. Specifically, the single-fiber RS-OCT probe is constructed using a double-clad fiber (DCF) and gradient index (GRIN) lens architecture. The DCF's single-mode core delivers and collects OCT light for high-resolution structural imaging, whereas its high-numerical-aperture multimode inner cladding coupled to the GRIN fiber lens facilitates efficient Raman excitation and collection along an identical optical axis, ensuring truly coaxial and co-registered tissue measurements. A free-space coupling scheme incorporating spatial filtering effectively suppresses both fiber-originated Raman background and DCF-induced OCT multipath artifacts, achieving artifact-free biochemical-microstructural integration within a compact intraoral probe. The resulting system achieves <math><mrow><mo>∼</mo> <mn>100</mn> <mtext>  </mtext> <mi>dB</mi></mrow> </math> OCT imaging sensitivity and acquires both fingerprint (880 to <math><mrow><mn>1800</mn> <mtext>  </mtext> <msup><mi>cm</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> </math> ) and high-wavenumber (2800 to <math><mrow><mn>3600</mn> <mtext>  </mtext> <msup><mi>cm</mi> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> </math> ) tissue Raman spectra within sub-seconds. We validated the hybrid RS-OCT system through <i>in vivo</i> oral measurements across nine anatomically distinct intraoral sites in healthy volunteers, including challenging posterior tongue regions. To synergistically fuse the co-registered morpho-chemical datasets, we implemented a cross-modality deep learning framework. This model, integrating OCT patch-voting with a dual-region Raman branch (fingerprint and high wavenumber), achieved a superior overall classification accuracy of 92.38% across all nine sites. This represents a significant diagnostic improvement of 16.55% and 21.19% over Raman-only (75.83%) and OCT-only (71.19%) modalities, respectively. Notably, the RS-OCT cross-modality deep learning model attained 93.4% accuracy within high-risk tongue sub-regions. This work establishes the single-fiber-enabled hybrid RS-OCT technique as a promising tool for enhanced <i>in vivo</i> oral tissue diagnosis with strong potential for broader clinical translations.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"035004"},"PeriodicalIF":0.0,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557451/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Raman spectroscopy for nondestructive detection of vaginal tissue alterations in the fibulin-5 murine model of pelvic organ prolapse.","authors":"Triniti N Vanoven, Fatemeh Vahidi Zaman, Evelyn T Pan, Jessica K Baas, Maria E Florian-Rodriguez, Kristin S Miller, Isaac J Pence","doi":"10.1117/1.BIOS.3.3.032106","DOIUrl":"10.1117/1.BIOS.3.3.032106","url":null,"abstract":"<p><strong>Significance: </strong>Pelvic organ prolapse (POP) is a gynecologic condition where one or more pelvic organs herniate into the vaginal canal that is characterized by suboptimal treatment options, a poorly understood pathophysiology, and a 50% lifetime risk of symptomatic manifestation. The main modality to assess severity is the pelvic organ prolapse quantification (POP-Q) system; however, the POP-Q system, in addition to clinical imaging methods such as MRI and ultrasound, is blind to extracellular matrix (ECM) changes that may relate to loss of tissue compliance.</p><p><strong>Aim: </strong>We aimed to establish a nondestructive approach to measure optical biomarkers of POP using Raman spectroscopy as well as complementary assays for tissue compliance and remodeling.</p><p><strong>Approach: </strong>Twenty-four nulliparous fibulin-5 sufficient (wildtype) and deficient (knockout) mice were sacrificed at estrus (20 to 26 weeks old; <math><mrow><mi>n</mi> <mo>=</mo> <mn>12</mn> <mo>/</mo> <mtext>genotype</mtext></mrow> </math> ) and full thickness vaginal samples ( <math><mrow><mn>5</mn> <mo>×</mo> <mn>5</mn> <mtext>  </mtext> <mi>mm</mi></mrow> </math> ) from the ventral wall were collected. Raman spectra were acquired and averaged from the vaginal epithelium for compositional analysis. Samples were then speckle-coated and tested using planar biaxial protocols to elucidate biomechanical properties. Finally, samples were subjected to histological sectioning and staining for validation. Spectral modeling and statistical analyses were performed, investigating associations between optical and histological composition with biomechanical measures of tissue compliance.</p><p><strong>Results: </strong>Optical biomarkers of mature, functional elastic fibers significantly decreased in the knockout mice when compared with their wildtype littermates and correlated to histological quantification. In addition, the knockout vagina had direction-dependent alterations in tissue biomechanical response. Nondestructive imaging further identified dysregulated metabolism wherein optical and histological glycogen content significantly decreased when compared with the wildtype controls.</p><p><strong>Conclusions: </strong>Herein, we have established and verified a workflow for non-destructive compositional analysis with future implications in noninvasive clinical POP evaluation and treatment monitoring. Further, we have established potential optical biomarkers related to dysregulated elastogenesis with POP, such as the <math> <mrow><msub><mi>I</mi> <mn>1101</mn></msub> <mo>/</mo> <msub><mi>I</mi> <mn>1654</mn></msub> </mrow> </math> mature, functional elastic fiber to ECM protein ratio.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"032106"},"PeriodicalIF":0.0,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557458/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extracorporeal near-infrared-activated antimicrobial photodynamic therapy for pneumonia using an ICG-polymer formulation.","authors":"Lorraine Gabriele Fiuza, Isabelle Almeida de Lima, Fernanda Alves, Michelle Barreto Requena, Vadila Giovana Guerra, Layla Pires, Cristina Kurachi, Natalia Mayumi Inada, Vanderlei Salvador Bagnato","doi":"10.1117/1.BIOS.3.3.035002","DOIUrl":"10.1117/1.BIOS.3.3.035002","url":null,"abstract":"<p><strong>Significance: </strong>Pneumonia remains a global health challenge, exacerbated by antimicrobial resistance, which limits the effectiveness of conventional treatments. Antimicrobial photodynamic therapy (aPDT) has emerged as a promising alternative for lower respiratory infections; however, its <i>in vivo</i> performance is hindered by lung surfactant, which traps photosensitizers and reduces their ability to reach bacterial targets.</p><p><strong>Aim: </strong>To address this limitation, recent studies demonstrated that combining indocyanine green (ICG) with the polymer Gantrez AN-139 enhances photodynamic activity even in the presence of lung surfactants.</p><p><strong>Approach: </strong>We assessed the therapeutic potential of this formulation in a murine pneumonia model using pulmonary delivery followed by 808 nm infrared irradiation.</p><p><strong>Results: </strong>Nebulization of <math><mrow><mn>200</mn> <mtext>  </mtext> <mi>μ</mi> <mi>M</mi></mrow> </math> ICG with 4% Gantrez AN-139 and irradiation at <math><mrow><mn>120</mn> <mtext>  </mtext> <mi>J</mi> <mo>/</mo> <msup><mi>cm</mi> <mn>2</mn></msup> </mrow> </math> yielded the best results, reducing bacterial load by up to <math><mrow><mn>3</mn> <mtext> </mtext> <msub><mrow><mi>log</mi></mrow> <mrow><mn>10</mn></mrow> </msub> </mrow> </math> and improving survival to 80%, compared with 40% in controls.</p><p><strong>Conclusion: </strong>These findings validate the formulation and the procedure for further animal studies.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"035002"},"PeriodicalIF":0.0,"publicationDate":"2026-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557454/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transient infrared laser exposure modulates calcium activity in cortical dendritic spines.","authors":"Jacob Hardenburger, George Grow, Pratheepa Rasiah, Mona Gerges, Joel Bixler, Chad Oian, Bryan Millis, Christopher Valdez, E Duco Jansen, Anita Mahadevan-Jansen","doi":"10.1117/1.BIOS.3.3.035001","DOIUrl":"10.1117/1.BIOS.3.3.035001","url":null,"abstract":"<p><strong>Significance: </strong>Infrared neural stimulation (INS) is an optical neuromodulation technique that elicits neural activity through photothermal temperature gradients. Photothermal gradients have been shown to alter neuronal excitability, but the effects on the dendritic spine (DS) structure and function have not been characterized.</p><p><strong>Aim: </strong>We aim to determine whether INS induces calcium signaling in DS and whether this signaling alters filamentous actin (F-actin).</p><p><strong>Approach: </strong>We used confocal imaging of cortical neurons expressing a genetically encoded calcium indicator (GCaMP)8f-Syn1 and mCardinal-LifeAct during laser exposure. Fluorescence signals were measured within regions of interest covering the DS. The resulting fluorescence measurements were baseline-normalized, and transient spiking activity in DS was quantified.</p><p><strong>Results: </strong>Transient thermal gradients induce persistent calcium activity in a fraction of DS, independent of pulse duration but dependent on the absolute temperature and number of laser exposures. There is no relationship between the calcium activity and F-actin. Calcium signaling in DS was not mediated by ionotropic glutamate receptors but depended on extracellular entry.</p><p><strong>Conclusions: </strong>These results indicate that transient thermal gradients elicit calcium activity in DS, but the induced activity does not alter F-actin, suggesting that transient thermal gradients may be a useful tool for studying calcium dynamics in DS without triggering traditional structural plasticity pathways.</p>","PeriodicalId":519981,"journal":{"name":"Biophotonics discovery","volume":"3 3","pages":"035001"},"PeriodicalIF":0.0,"publicationDate":"2026-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13557455/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}