Biophotonics discovery最新文献

Significance: Anemia remains a substantial global health challenge. Delayed detection often leads to various health complications. In school-age children, anemia can impair both cognitive and physical development. Timely detection is particularly critical for this vulnerable population as effective interventions are available even in resource-limited settings.

Aim: Most existing methods for assessing conjunctiva paleness or redness in anemia detection rely on colorimetric analyses or spectral imaging, which require sophisticated color processing methods or specialized equipment. We introduce an alternative that takes advantage of purely spatial and textural characteristics of the conjunctiva microvasculature for anemia detection.

Approach: Radiomics, an emerging machine learning approach for conventional medical imaging, is applied to conjunctiva photos to analyze morphological alterations in the microvasculature beyond direct visualization. Radiomic analyses are conducted on 12,441 palpebral and 12,375 bulbar conjunctiva photos, captured using three different smartphone models from 565 children aged 5 to 15 years.

Results: Spatial and textural features extracted from the palpebral and bulbar conjunctivae are significantly associated with anemia status in school-age children, demonstrating their potential as biomarkers of anemia.

Conclusions: Instead of relying on color-based or spectral analyses of pallor in the conjunctiva, the proposed framework lays the groundwork for simplifying the hardware and algorithmic requirements of point-of-care, noninvasive anemia screening in sub-Saharan Africa and other resource-limited settings.

Significance: Human pluripotent stem-cell-derived cardiomyocytes (hPSC-CMs) are a powerful tool for drug discovery, and metabolic changes are associated with their long-term culture and maturation. However, the lack of technologies to monitor hPSC-derived cardiomyocyte metabolism during long-term culture presents a major technical bottleneck.

Aim: Efforts to monitor in vitro metabolic maturation of hPSC-CMs are limited by traditional assessment methods, which are generally time-consuming, destructive to samples, and lack single-cell resolution. We report a rapid, noninvasive imaging-based method to monitor hPSC-CM metabolism throughout extended culture (90+ days).

Approach: Label-free optical metabolic imaging (OMI) of autofluorescent metabolic coenzymes was performed at multiple time points during the extended culture maturation process. In addition, OMI monitored hPSC-CMs grown on substrates with varying stiffness and on cardiomyocytes derived from induced pluripotent stem cells associated with cardiac arrhythmia. OMI was paired with immunofluorescence to validate structural maturation.

Results: Single-cell OMI can identify metabolic changes during cardiomyocyte maturation through extended in vitro culturing. It can also detect metabolic differences induced by substrates of varying stiffnesses, can distinguish diseased from normal cell lines, and is sensitive to patient-level metabolic heterogeneity.

Conclusions: Our results demonstrate that label-free OMI can be used to monitor metabolic changes in hPSC-CMs under varying culture conditions in a rapid, non-destructive manner with single-cell resolution, providing insight into metabolic transitions arising from time in culture, culture conditions, or disease states.

Significance: Second-harmonic generation (SHG) analysis of collagen internal structure and overall organization in the tumor microenvironment may enhance current metastasis prediction methods, which do not prognosticate with the same accuracy for patients of different races. For these optical tools to be clinically available, a multicenter trial is needed. We investigate if SHG-based prognostic signals vary with patient race, providing insight for designing such a trial.

Aim: SHG imaging was performed on colon adenocarcinoma (CRC) and invasive ductal carcinoma (IDC) patient samples to derive two prognostic indicators. We assessed the association between these indicators and patient race.

Approach: SHG images were analyzed as previously described to determine the forward- to backward-SHG scattering ratio (F/B) and fiber angle variability (FAV). Both prognostic measurements were compared between Black and White patients.

Results: In the IDC cohort, F/B from the tumor-stroma interface differed significantly between demographic groups. For the CRC cohort, a trend was observed in the tumor-stroma interface and tumor bulk. FAV did not vary by race in either cohort.

Conclusions: F/B variation with patient race suggests the relationship between F/B and metastatic outcome may vary with patient race. These findings highlight the potential need for race-specific prognostic algorithms to improve metastasis prediction for all patients.

Significance: Radioresistance remains a significant problem for head and neck squamous cell carcinoma (HNSCC) patients. To mitigate this, the cellular and molecular pathways used by radioresistant HNSCC that drive recurrence must be studied.

Aim: We aim to demonstrate optical imaging strategies to provide flow cytometry-like single-cell level analysis of hypoxia-inducible factor 1-alpha (HIF-1α)-mediated metabolic changes in the radioresistant and radiosensitive HNSCC cells but in a more efficient, cost-effective, and non-destructive manner. Through both optical imaging and flow cytometry studies, we will reveal the role of radiation-induced HIF-1α overexpression and the following metabolic changes in the radioresistance development for HNSCC.

Approach: We optimized the use of two metabolic probes: 2-[N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino]-2-deoxy-D-glucose (2-NBDG) (to report glucose uptake) and Tetramethylrhodamine ethyl ester (TMRE) (to report mitochondrial membrane potential) with both a standard fluorescence microscope and a flow cytometry device, to report the changes in metabolism between radioresistant (rSCC-61) and radiosensitive (SCC-61) HNSCC cell lines under radiation stresses with or without HIF-1α inhibition.

Results: We found that the matched HNSCC cell lines had different baseline metabolic phenotypes, and their metabolism responded differently to radiation stress along with significantly enhanced HIF-1α expressions in the rSCC-61 cells. HIF-1α inhibition during the radiation treatment modulates the metabolic changes and radio-sensitizes the rSCC-61 cells. Through these studies, we demonstrated that a standard fluorescence microscope along with proper image processing methods can provide flow cytometry-like single-cell level analysis of HIF-1α-mediated metabolic changes in the radioresistant and radiosensitive HNSCC cells.

Conclusions: Our reported optical imaging strategies may enable one to study the role of metabolism reprogramming in cancer therapeutic resistance development at the single-cell level in a more efficient, cost-effective, and non-destructive manner. Our understanding of radiation resistance mechanisms using our imaging methods will offer opportunities to design targeted radiotherapy for improved treatment outcomes for HNSCC patients.

Significance: Photoacoustic imaging has the potential to improve non-invasive breast cancer diagnosis. However, illumination through the skin introduces a skin tone bias, as greater melanin content increases optical absorption and can create acoustic clutter, reducing the visibility of various target sizes.

Aim: We investigate the impact of skin tone bias as a function of target sizes in three photoacoustic image reconstruction methods: fast Fourier transform (FFT)-based reconstruction, delay-and-sum (DAS) beamforming, and short-lag spatial coherence (SLSC) beamforming.

Methods: The three imaging methods were applied to channel data from multidomain simulations with 757, 800, and 1064 nm wavelengths, 11 target sizes (ranging 0.5 to 3 mm), 18 skin tones [ranging individual typology angles (ITAs) of -54 deg to 60 deg], and a previously validated realistic 3D breast model. The signal-to-noise ratio (SNR) and generalized contrast-to-noise ratio (gCNR) were measured to assess visibility.

Results: With 757 and 800 nm wavelengths, targets underlying dark skin tones (ITA range: -54 deg to -33 deg) with sizes ≤3 mm were poorly visible with ≤2.38 to 4.21 mean SNR and ≤0.46 to 0.74 mean gCNR, with smaller targets generally being more visible with lighter skin tones. A 1064-nm transmit wavelength improved visualization with DAS and SLSC beamforming, relative to both FFT reconstruction with a 1064 nm wavelength and DAS or SLSC beamforming with 757 and 800 nm wavelengths. When combined with SLSC beamforming, the 1064-nm wavelength offered the greatest improvements, enabling visualization of simulated target sizes ranging from 0.5 to 3 mm underlying very light (ITA = 60 deg) to dark (ITA = -54 deg) skin tones, with mean SNR ≤10.01 and mean gCNR ≤1. Visualization of simulated vessel structures derived from in vivo photoacoustic images was consistent with simulation-based target size expectations.

Conclusions: Results are promising for advancing next-generation photoacoustic imaging systems for breast cancer diagnosis across the range of skin tones represented in healthcare systems throughout the world.

Significance: Heart disease is the leading cause of death in the United States, yet research is limited by the inability to culture primary cardiac cells. Cardiomyocytes (CMs) derived from human induced pluripotent stem cells (iPSCs) are a promising solution for drug screening and disease modeling.

Aim: Induced pluripotent stem cell-derived CM (iPSC-CM) differentiation and maturation studies typically use heterogeneous substrates for growth and destructive verification methods. Reproducible, tunable substrates and touch-free monitoring are needed to identify ideal conditions to produce homogenous, functional CMs.

Approach: We generated synthetic polyethylene glycol-based hydrogels for iPSC-CM differentiation and maturation. Peptide concentrations, combinations, and gel stiffness were tuned independently. Label-free optical redox imaging (ORI) was performed on a widefield microscope in a 96-well screen of gel formulations. We performed live-cell imaging throughout differentiation and early to late maturation to identify key metabolic shifts.

Results: Label-free ORI confirmed the expected metabolic shifts toward oxidative phosphorylation throughout the differentiation and maturation processes of iPSC-CMs on synthetic hydrogels. Furthermore, ORI distinguished high and low differentiation efficiency cell batches in the cardiac progenitor stage.

Conclusions: We established a workflow for medium throughput screening of synthetic hydrogel conditions with the ability to perform repeated live-cell measurements and confirm expected metabolic shifts. These methods have implications for reproducible iPSC-CM generation in biomanufacturing.

Significance: Increased collagen linearization and deposition during tumorigenesis can impede immune cell infiltration and lead to tumor metastasis. Although melanoma is well studied in immunotherapy research, studies that quantify collagen changes during melanoma progression and treatment are lacking.

Aim: We aim to image in vivo collagen in preclinical melanoma models during immunotherapy and quantify the collagen phenotype in treated and control mice.

Approach: Second-harmonic generation imaging of collagen was performed in mouse melanoma tumors in vivo over a treatment time course. Animals were treated with a curative radiation and immunotherapy combination. Collagen morphology was quantified over time at an image and single-fiber level using CurveAlign and CT-FIRE software.

Results: In immunotherapy-treated mice, collagen was reorganized toward a healthy phenotype, including shorter, wider, curlier collagen fibers, with modestly higher collagen density. Temporally, collagen fiber straightness and length changed late in treatment (days 9 and 12), while width and density changed early (day 6) compared with control mice. Single-fiber collagen features calculated in CT-FIRE were the most sensitive to the changes among treatment groups compared with bulk collagen features.

Conclusions: Quantitative second-harmonic generation imaging can provide insight into collagen dynamics in vivo during immunotherapy, with key implications in improving immunotherapy response in melanoma and other cancers.