Exploring near-infrared autofluorescence properties in parathyroid tissue: an analysis of fresh and paraffin-embedded thyroidectomy specimens.

Significance: Near-infrared autofluorescence (NIRAF) utilizes the natural autofluorescence of parathyroid glands (PGs) to improve their identification during thyroid surgeries, reducing the risk of inadvertent removal and subsequent complications such as hypoparathyroidism. This study evaluates NIRAF's effectiveness in real-world surgical settings, highlighting its potential to enhance surgical outcomes and patient safety. Aim: We evaluate the effectiveness of NIRAF in detecting PGs during thyroidectomy and central neck dissection and investigate autofluorescence characteristics in both fresh and paraffin-embedded tissues. Approach: We included 101 patients diagnosed with papillary thyroid cancer who underwent surgeries in 2022 and 2023. We assessed NIRAF's ability to locate PGs, confirmed via parathyroid hormone assays, and involved both junior and senior surgeons. We measured the accuracy, speed, and agreement levels of each method and analyzed autofluorescence persistence and variation over 10 years, alongside the expression of calcium-sensing receptor (CaSR) and vitamin D. Results: NIRAF demonstrated a sensitivity of 89.5% and a negative predictive value of 89.1%. However, its specificity and positive predictive value (PPV) were 61.2% and 62.3%, respectively, which are considered lower. The kappa statistic indicated moderate to substantial agreement (kappa = 0.478; P < 0.001 ). Senior surgeons achieved high specificity (86.2%) and PPV (85.3%), with substantial agreement (kappa = 0.847; P < 0.001 ). In contrast, junior surgeons displayed the lowest kappa statistic among the groups, indicating minimal agreement (kappa = 0.381; P < 0.001 ). Common errors in NIRAF included interference from brown fat and eschar. In addition, paraffin-embedded samples retained stable autofluorescence over 10 years, showing no significant correlation with CaSR and vitamin D levels. Conclusions: NIRAF is useful for PG identification in thyroid and neck surgeries, enhancing efficiency and reducing inadvertent PG removals. The stability of autofluorescence in paraffin samples suggests its long-term viability, with false positives providing insights for further improvements in NIRAF technology.

Impact of signal-to-noise ratio and contrast definition on the sensitivity assessment and benchmarking of fluorescence molecular imaging systems.

Significance: Standardization of fluorescence molecular imaging (FMI) is critical for ensuring quality control in guiding surgical procedures. To accurately evaluate system performance, two metrics, the signal-to-noise ratio (SNR) and contrast, are widely employed. However, there is currently no consensus on how these metrics can be computed. Aim: We aim to examine the impact of SNR and contrast definitions on the performance assessment of FMI systems. Approach: We quantified the SNR and contrast of six near-infrared FMI systems by imaging a multi-parametric phantom. Based on approaches commonly used in the literature, we quantified seven SNRs and four contrast values considering different background regions and/or formulas. Then, we calculated benchmarking (BM) scores and respective rank values for each system. Results: We show that the performance assessment of an FMI system changes depending on the background locations and the applied quantification method. For a single system, the different metrics can vary up to ∼ 35 dB (SNR), ∼ 8.65 a . u . (contrast), and ∼ 0.67 a . u . (BM score). Conclusions: The definition of precise guidelines for FMI performance assessment is imperative to ensure successful clinical translation of the technology. Such guidelines can also enable quality control for the already clinically approved indocyanine green-based fluorescence image-guided surgery.

Comparison of Tumor Non-specific and PD-L1 Specific Imaging by Near-Infrared Fluorescence/Cerenkov Luminescence Dual-Modality In-situ Imaging.

Background: Labeled antibodies are excellent imaging agents in oncology to non-invasively visualize cancer-related antigens expression levels. However, tumor tracer uptake (TTU) of specific antibodies in-vivo may be inferior to non-specific IgG in some cases. Objectives: To explore factors affecting labeled antibody visualization by PD-L1 specific and non-specific imaging of nude mouse tumors. Methods: TTU was observed in RKO model on Cerenkov luminescence (CL) and near-infrared fluorescence (NIRF) imaging of radionuclide 131I or NIRF dyes labeled Atezolizumab and IgG. A mixture of NIRF dyes labeled Atezolizumab and 131I-labeled IgG was injected, and TTU was observed in the RKO and HCT8 model by NIRF/CL dual-modality in-situ imaging. TTU were observed by 131I-labeled Atezolizumab and IgG in-vitro distribution. Results: Labeled IgG concentrated more in tumors than Atezolizumab. NIRF/CL imaging in 24 to 168 h showed that TTU gradually decreased over time, which decreased more slowly on CL imaging compared to NIRF imaging. The distribution data in-vitro showed that TTU of 131I-labeled IgG was higher than that of 131I-labeled Atezolizumab at any time point. Conclusion: Non-specific IgG may not be suitable as a control for Atezolizumab in comparing tumor PD-L1 expression in nude mice via labeled antibody optical imaging under certain circumstances.

Relationship between locomotive syndrome and advanced glycation end products measured by skin autofluorescence in community-dwelling patients: the Yakumo Study.

Advanced glycation end products (AGEs) have been reported to be associated with osteoporosis, aging, sarcopenia, and frailty. This study aimed to investigate the association AGEs with locomotive syndrome (LS). Participants were Japanese individuals aged 39 years or older who participated in the Yakumo Study (n=230). AGEs were measured by skin autofluorescence (SAF) using an AGE reader. We investigated SAF values for each locomotive stage. Multivariate logistic regression models were used to calculate the odds ratios of LS-associated factors. The relationships between SAF and physical performance and bone mineral density (BMD) were investigated. A receiver operating characteristic (ROC) curves were generated to determine the optimal cut-off value of SAF for predicting LS. SAF values tended to increase correspondingly with LS severity. SAF was an independently explanatory factor for LS (odds ratio 2.70; 95% confidence interval [CI] 1.040-6.990). SAF was positively correlated with the 10-m walking speed, The Timed Up and Go test results, and was negatively correlated with BMD. ROC curve represented by SAF for the presence or absence of LS risk had an area under the curve of 0.648 (95% CI: 0.571-0.726). High SAF values were identified as an independent risk factor for LS. AGEs could be a potential screening tool for people for LS.

Multispectral label-free in vivo cellular imaging of human retinal pigment epithelium using adaptive optics fluorescence lifetime ophthalmoscopy improves feasibility for low emission analysis and increases sensitivity for detecting changes with age and eccentricity.

Significance: Adaptive optics fluorescence lifetime ophthalmoscopy (AOFLIO) provides a label-free approach to observe functional and molecular changes at cellular scale in vivo. Adding multispectral capabilities improves interpretation of lifetime fluctuations due to individual fluorophores in the retinal pigment epithelium (RPE). Aim: To quantify the cellular-scale changes in autofluorescence with age and eccentricity due to variations in lipofuscin, melanin, and melanolipofuscin in RPE using multispectral AOFLIO. Approach: AOFLIO was performed on six subjects at seven eccentricities. Four imaging channels ( λ ex / λ em ) were used: 473/SSC, 473/LSC, 532/LSC, and 765/NIR. Cells were segmented and the timing signals of each pixel in a cell were combined into a single histogram, which were then used to compute the lifetime and phasor parameters. An ANOVA was performed to investigate eccentricity and spectral effects on each parameter. Results: A repeatability analysis revealed < 11.8 % change in lifetime parameters in repeat visits for 532/LSC. The 765/NIR and 532/LSC had eccentricity and age effects similar to previous reports. The 473/LSC had a change in eccentricity with mean lifetime and a phasor component. Both the 473/LSC and 473/SSC had changes in eccentricity in the short lifetime component and its relative contribution. The 473/SSC had no trend in eccentricity in phasor. The comparison across the four channels showed differences in lifetime and phasor parameters. Conclusions: Multispectral AOFLIO can provide a more comprehensive picture of changes with age and eccentricity. These results indicate that cell segmentation has the potential to allow investigations in low-photon scenarios such as in older or diseased subjects with the co-capture of an NIR channel (such as 765/NIR) with the desired spectral channel. This work represents the first multispectral, cellular-scale fluorescence lifetime comparison in vivo in the human RPE and may be a useful method for tracking diseases.

Polaron engineering promotes NIR-II absorption of carbon quantum dots for bioimaging and cancer therapy.

Recent years have witnessed a surge of interest in tuning the optical properties of organic semiconductors for diverse applications. However, achieving control over the optical bandgap in the second near-infrared (NIR-II) window has remained a major challenge. To address this, here we report a polaron engineering strategy that introduces diverse defects into carbon quantum dots (CQDs). These defects induce lattice distortions resulting in the formation of polarons, which can absorb the near-field scattered light. Furthermore, the formed polarons in N-related vacancies can generate thermal energy through the coupling of lattice vibrations, while the portion associated with O-related defects can return to the ground state in the form of NIR-II fluorescence. On the basis of this optical absorption model, these CQDs have been successfully applied to NIR-II fluorescence imaging and photothermal therapy. This discovery could open a promising route for the polarons of organic semiconductor materials as NIR-II absorbers in nanomedical applications.

Morphology, Fundus Autofluorescence, and Retinal Sensitivity of Photocoagulated Lesions in Proliferative Diabetic Retinopathy.

Purpose: To evaluate the relationships among morphology, fundus autofluorescence (FAF), and retinal sensitivity of photocoagulated lesions more than 1 year after panretinal photocoagulation in patients with proliferative diabetic retinopathy and good vision. Methods: This retrospective cohort study included patients with proliferative diabetic retinopathy who had undergone panretinal photocoagulation more than 1 year ago. The photocoagulated lesions were classified according to FAF levels: group A, no FAF; group B, diffuse FAF; group C, white-dotted centers with diffuse FAF; group D, white-dotted centers without FAF; and group E, controls. The main outcome measures were FAF, retinal sensitivity, and morphology of the photocoagulated lesions. Results: The median sensitivity values and number of photocoagulated lesions in groups A (n = 37), B (n = 39), C (n = 4), D (n = 15), and E (n = 39) were 0 dB, 18.0 dB, 13.9 dB, 0.3 dB, and 21.5 dB, respectively. EZ lines were absent in 93.5%, 18.1%, 50%, 93.3%, and 0% of lesions in groups A, B, C, D, and E, respectively. The inner retinal layer was damaged in 45.2%, 3.0%, 50%, 73.3%, and 0% lesions in groups A, B, C, D, and E, respectively. Statistically significant between-group differences were observed in the retinal sensitivities of the photocoagulated lesions, presence of EZ lines, and damage to the inner retinal layer (p < 0.05). Conclusions: The photoreceptors in most photocoagulated lesions with diffuse FAF retain their morphology and function. Translational Relevance: Using fundus autofluorescence, the damage to photoreceptors after panretinal photocoagulation in patients with diabetes can be estimated in a noninvasive manner. This process can help in determining the need for additional panretinal photocoagulation.

A smart hypochlorous acid fluorescent probe enabling Ibuprofen-release for osteoarthritis theranostics.

Background: Osteoarthritis (OA) standing as the most prevalent form of arthritis, closely associates with heightened levels of reactive oxygen species, particularly hypochlorous acid (HOCl). Although there are numerous probes available for detecting HOCl in the OA region, probes with dual functions of diagnostic and therapeutic capabilities are still significantly lacking. While this type of probe can reduce the time gap between diagnosis and treatment, which is clinically needed. Methods: We developed a fluorescent probe (DHU-CBA1) toward HOCl with theranostics functions through the release of methylene blue (MB) and ibuprofen (IBP) in this work. DHU-CBA1 can detect HOCl with high specificity and sensitivity, releasing MB and IBP with an impressive efficiency of ≥ 95% in vitro. Results: DHU-CBA1 exhibits good biosafety, enabling in vivo imaging of endogenous HOCl, along with reducing arthritis scores, improving synovitis and cartilage damage, and maintaining catabolic balance while alleviating senescence in cartilage. Conclusions: This study proposes a novel approach to enhance osteoarthritis therapy by releasing IBP via a smart HOCl-enabled fluorescent probe.

Role of indocyanine green-guided near-infrared fluorescence imaging in identification of the cause of neonatal cholestasis.

To evaluate the efficacy and safety of indocyanine green (ICG)-guided near-infrared fluorescence (NIRF) imaging during surgery to diagnose the cause of neonatal cholestasis (NC). Data on NC patients who underwent both NIRF with ICG and conventional laparoscopic bile duct exploration (the gold standard) at our institute from January 2022 to December 2022 were retrospectively analyzed. The patients' baseline characteristics and liver function outcomes were collected and analyzed, and the diagnostic consistency was compared between the 2 methods. In total, 16 NC patients were included in the study, comprising 8 (50%) male and 8 (50%) female patients, ranging in age from 42 to 93 days, with a median age of 54.4 ±â€…21 days. During surgery, all the patients underwent NIRF with ICG, followed by conventional laparoscopic bile duct exploration. Finally, 15 of the patients were diagnosed with biliary atresia (BA) (1 with type-I BA, and 14 with type-II BA). The other patient was diagnosed with cholestasis. The diagnostic results from fluorescence imaging with ICG were consistent with those from conventional laparoscopic bile duct exploration. ICG-guided NIRF is associated with an easy operation, less trauma, and good safety. Also, its diagnostic accuracy is similar to conventional laparoscopic bile duct exploration.

Convolutional neural network advances in demosaicing for fluorescent cancer imaging with color-near-infrared sensors.

Significance: Single-chip imaging devices featuring vertically stacked photodiodes and pixelated spectral filters are advancing multi-dye imaging methods for cancer surgeries, though this innovation comes with a compromise in spatial resolution. To mitigate this drawback, we developed a deep convolutional neural network (CNN) aimed at demosaicing the color and near-infrared (NIR) channels, with its performance validated on both pre-clinical and clinical datasets. Aim: We introduce an optimized deep CNN designed for demosaicing both color and NIR images obtained using a hexachromatic imaging sensor. Approach: A residual CNN was fine-tuned and trained on a dataset of color images and subsequently assessed on a series of dual-channel, color, and NIR images to demonstrate its enhanced performance compared with traditional bilinear interpolation. Results: Our optimized CNN for demosaicing color and NIR images achieves a reduction in the mean square error by 37% for color and 40% for NIR, respectively, and enhances the structural dissimilarity index by 37% across both imaging modalities in pre-clinical data. In clinical datasets, the network improves the mean square error by 35% in color images and 42% in NIR images while enhancing the structural dissimilarity index by 39% in both imaging modalities. Conclusions: We showcase enhancements in image resolution for both color and NIR modalities through the use of an optimized CNN tailored for a hexachromatic image sensor. With the ongoing advancements in graphics card computational power, our approach delivers significant improvements in resolution that are feasible for real-time execution in surgical environments.

Hyperspectral imaging of 4T1 mammary carcinomas grown in dorsal skinfold window chambers: spectral renormalization and fluorescence modeling.

Significance: Hyperspectral imaging (HSI) of murine tumor models grown in dorsal skinfold window chambers (DSWCs) offers invaluable insight into the tumor microenvironment. However, light loss in a glass coverslip is often overlooked, and particular tissue characteristics are improperly modeled, leading to errors in tissue properties extracted from hyperspectral images. Aim: We highlight the significance of spectral renormalization in HSI of DSWC models and demonstrate the benefit of incorporating enhanced green fluorescent protein (EGFP) excitation and emission in the skin tissue model for tumors expressing genes to produce EGFP. Approach: We employed an HSI system for intravital imaging of mice with 4T1 mammary carcinoma in a DSWC over 14 days. We performed spectral renormalization of hyperspectral images based on the measured reflectance spectra of glass coverslips and utilized an inverse adding-doubling (IAD) algorithm with a two-layer murine skin model, to extract tissue parameters, such as total hemoglobin concentration and tissue oxygenation ( StO 2 ). The model was upgraded to consider EGFP fluorescence excitation and emission. Moreover, we conducted additional experiments involving tissue phantoms, human forearm skin imaging, and numerical simulations. Results: Hyperspectral image renormalization and the addition of EGFP fluorescence in the murine skin model reduced the mean absolute percentage errors (MAPEs) of fitted and measured spectra by up to 10% in tissue phantoms, 0.55% to 1.5% in the human forearm experiment and numerical simulations, and up to 0.7% in 4T1 tumors. Similarly, the MAPEs for tissue parameters extracted by IAD were reduced by up to 3% in human forearms and numerical simulations. For some parameters, statistically significant differences ( p < 0.05 ) were observed in 4T1 tumors. Ultimately, we have shown that fluorescence emission could be helpful for 4T1 tumor segmentation. Conclusions: The results contribute to improving intravital monitoring of DWSC models using HSI and pave the way for more accurate and precise quantitative imaging.

AUNP-12 Near-Infrared Fluorescence Probes across NIR-I to NIR-II Enable In Vivo Detection of PD-1/PD-L1 Axis in the Tumor Microenvironment.

The innovative PD-1/PD-L1 pathway strategy is gaining significant traction in cancer therapeutics. However, fluctuating response rates of 20-40% to PD-1/PD-L1 inhibitors, coupled with the risk of hyperprogression after immunotherapy, underscore the need for accurate patient selection and the identification of more beneficiaries. Molecular imaging, specifically near-infrared (NIR) fluorescence imaging, is a valuable alternative for real-time, noninvasive visualization of dynamic PD-L1 expression in vivo. This research introduces AUNP-12, a novel PD-L1-targeting peptide antagonist conjugated with Cy5.5 and CH1055 for first (NIR-I) and second near-infrared (NIR-II) imaging. These probes have proven to be effective in mapping PD-L1 expression across various mouse tumor models, offering insights into tumor-immune interactions. This study highlights the potential of AUNP-12-Cy5.5 and AUNP-12-CH1055 for guiding clinical immunotherapy through precise patient stratification and dynamic monitoring, supporting the shift toward molecular imaging for personalized cancer care.

A Mitochondria-Targeting Fluorescent Probe for the Dual Sensing of Hypochlorite and Viscosity without Signal Crosstalk in Living Cells and Zebrafish.

Hypochlorite (ClO-) and viscosity both affect the physiological state of mitochondria, and their abnormal levels are closely related to many common diseases. Therefore, it is vitally important to develop mitochondria-targeting fluorescent probes for the dual sensing of ClO- and viscosity. Herein, we have explored a new fluorescent probe, XTAP-Bn, which responds sensitively to ClO- and viscosity with off-on fluorescence changes at 558 and 765 nm, respectively. Because the emission wavelength gap is more than 200 nm, XTAP-Bn can effectively eliminate the signal crosstalk during the simultaneous detection of ClO- and viscosity. In addition, XTAP-Bn has several advantages, including high selectivity, rapid response, good water solubility, low cytotoxicity, and excellent mitochondrial-targeting ability. More importantly, probe XTAP-Bn is successfully employed to monitor the dynamic change in ClO- and viscosity levels in the mitochondria of living cells and zebrafish. This study not only provides a reliable tool for identifying mitochondrial dysfunction but also offers a potential approach for the early diagnosis of mitochondrial-related diseases.

The role of ureteric indocyanine green fluorescence in colorectal surgery: a retrospective cohort study.

BACKGROUND: Ureteric injury (UI) is an infrequent but serious complication of colorectal surgery. Prophylactic ureteric stenting is employed to avoid UI, yet its efficacy remains debated. Intraoperative indocyanine green fluorescence imaging (ICG-FI) has been used to facilitate ureter detection. This study aimed to investigate the role of ICG-FI in identification of ureters during colorectal surgery and its impact on the incidence of UI. METHODS: A retrospective cohort study involving 556 consecutive patients who underwent colorectal surgery between 2018 and 2023 assessed the utility of routine prophylactic ureteric stenting with adjunctive ICG-FI. Patients with ICG-FI were compared to those without ICG-FI. Demographic data, operative details, and postoperative morbidity were analyzed. Statistical analysis included univariable regression. RESULTS: Ureteric ICG-FI was used in 312 (56.1%) patients, whereas 43.9% were controls. Both groups were comparable in terms of demographics except for a higher prevalence of prior abdominal surgeries in the ICG-FI group. Although intraoperative visualization was significantly higher in the ICG-FI group (95.3% vs 89.1%; p = 0.011), the incidence of UI was similar between groups (0.3% vs 0.8%; p = 0.585). Postoperative complications were similar between the two groups. Median stent insertion time was longer in the ICG-FI group (32 vs 25 min; p = 0.001). CONCLUSION: Ureteric ICG-FI improved intraoperative visualization of the ureters but was not associated with a reduced UI rate. Median stent insertion time increased with use of ureteric ICG-FI, but total operative time did not. Despite its limitations, this study is the largest of its kind suggesting that ureteric ICG-FI may be a valuable adjunct to facilitate  ureteric visualization during colorectal surgery.

Tri-armed Schiff base fluorescent sensor for the rapid recognition of Zn(II): application in live cell imaging, test strips and TLC.

Various metal ions exist in nature and human beings and play limitless vital roles in both the atmosphere and biology. A fundamental and useful aspect is the qualitative and quantitative assessment of Zn(II) at concentration levels as low as parts per billion (ppb). Thus, the design and development of novel fluorescent turn-on receptors have gained significant interest because of their potential for use in live cell imaging to detect biologically relevant metal ions with high selectivity and sensitivity. The present research illustrates the design and synthesis of a novel fluorescent sensor [(1,3,5-triazine-2,4,6-triyl)tris(hydrazine-2-yl-1-ylidene)tris(methaneylylidene)]tris(2,4-di-tert-butylphenol) (THDBP) for the selective and sensitive probing of Zn(II). The sensor exhibited a fluorescence turn-on mechanism upon treatment with Zn(II) ions at λemi. 503 nm in aq. acetonitrile. The formation of a 1 : 3 complex between THDBP and Zn(II) is confirmed from the Job plot and ESI-MS spectrum. The evaluated limit of detection (LOD) and association constant (Ka) of the sensor THDBP for Zn(II) were found to be 1.03 × 10-10 M and 2.33 × 108 M-1, respectively. Further research demonstrates the practical application of the sensor for the detection of Zn(II) ions in live cells. The sensing ability of the sensor THDBP was also explored through inexpensive test strips and TLC sheets.

A phenothiazine-based ratiometric fluorescence probe for the detection of hydroxylamine in real water and living cells.

In this study, a phenothiazine-based ratiometric fluorescent probe PCHO was developed for highly sensitive and specific detection of hydroxylamine (HA). In the presence of HA, the aldehyde group on the PCHO molecule underwent a specific nucleophilic addition with HA to form an oxime group, accompanied by significant changes in fluorescence from green to blue. This detection mechanism was well supported by 1H NMR titration, HRMS and DFT calculations. The probe PCHO exhibited high sensitivity for HA detection (LOD was 0.19 µM) with a rapid response time (1 min), high selectivity and strong anti-interference performance. Surprisingly, the probe PCHO could selectively distinguish HA from its similar competing agents such as hydrazine and amines. Moreover, paper strips loaded with PCHO were prepared and combined with a smartphone to achieve point-of-care and visual detection of HA. The probe PCHO was further applied for the detection of HA in real water samples, achieving a recovery rate of 98.90% to 104.86% and an RSD of 0.86% to 2.44%, confirming the accuracy and reliability of the method. Additionally, the probe PCHO was used for imaging analysis of HA in living cells, providing a powerful visualization tool for exploring the physiological functions of HA in vivo.

METAPHOR: Metabolic evaluation through phasor-based hyperspectral imaging and organelle recognition for mouse blastocysts and oocytes.

Only 30% of embryos from in vitro fertilized oocytes successfully implant and develop to term, leading to repeated transfer cycles. To reduce time-to-pregnancy and stress for patients, there is a need for a diagnostic tool to better select embryos and oocytes based on their physiology. The current standard employs brightfield imaging, which provides limited physiological information. Here, we introduce METAPHOR: Metabolic Evaluation through Phasor-based Hyperspectral Imaging and Organelle Recognition. This non-invasive, label-free imaging method combines two-photon illumination and AI to deliver the metabolic profile of embryos and oocytes based on intrinsic autofluorescence signals. We used it to classify i) mouse blastocysts cultured under standard conditions or with depletion of selected metabolites (glucose, pyruvate, lactate); and ii) oocytes from young and old mouse females, or in vitro-aged oocytes. The imaging process was safe for blastocysts and oocytes. The METAPHOR classification of control vs. metabolites-depleted embryos reached an area under the ROC curve (AUC) of 93.7%, compared to 51% achieved for human grading using brightfield imaging. The binary classification of young vs. old/in vitro-aged oocytes and their blastulation prediction using METAPHOR reached an AUC of 96.2% and 82.2%, respectively. Finally, organelle recognition and segmentation based on the flavin adenine dinucleotide signal revealed that quantification of mitochondria size and distribution can be used as a biomarker to classify oocytes and embryos. The performance and safety of the method highlight the accuracy of noninvasive metabolic imaging as a complementary approach to evaluate oocytes and embryos based on their physiology.

Fluorescence imaging of lamellipodin-mediated biomolecular condensates on solid supported lipid bilayer membranes.

Biomolecular condensates play a major role in numerous cellular processes, including several that occur on the surface of lipid bilayer membranes. There is increasing evidence that cellular membrane trafficking phenomena, including the internalization of the plasma membrane through endocytosis, are mediated by multivalent protein-protein interactions that can lead to phase separation. We have recently found that proteins involved in the clathrin-independent endocytic pathway named Fast Endophilin Mediated Endocytosis can undergo liquid-liquid phase separation (LLPS) in solution and on lipid bilayer membranes. Here, the protein solution concentrations required for phase separation to be observed are significantly smaller compared to those required for phase separation in solution. LLPS is challenging to systematically characterize in cellular systems in general, and on biological membranes in particular. Model membrane approaches are more suitable for this purpose as they allow for precise control over the nature and amount of the components present in a mixture. Here we describe a method that enables the imaging of LLPS domain formation on solid supported lipid bilayers. These allow for facile imaging, provide long-term stability, and avoid clustering of vesicles and vesicle-attached features (such as buds and tethers) in the presence of multi-valent membrane interacting proteins.

Endoplasmic reticulum-targeted fluorescent probe with aggregation-induced emission features for imaging peroxynitrite in drug-induced liver injury model.

Drug-induced liver injury (DILI) poses a severe threat to public health. Endoplasmic reticulum (ER) stress contributes significantly to DILI pathogenesis, with peroxynitrite (ONOO-) identified as a pivotal indicator. However, the temporal and spatial fluctuations of ONOO- associated with ER stress in the pathogenesis of DILI remain unclear. Herein, a novel ER-specific near-infrared (NIR) probe (QM-ONOO) with aggregation-induced emission (AIE) features for monitoring ONOO- fluctuations in DILI was elaborately constructed. QM-ONOO exhibited excellent ER-targeting specificity, a large Stoke's shift, and a low detection limit (26.9 nM) toward ONOO-. QM-ONOO performed well in imaging both exogenous and endogenous ONOO- in HepG2 cells. Furthermore, molecular docking calculations validated the ER-targeting mechanism of QM-ONOO. Most importantly, using this probe allowed us to intuitively observe the dynamic fluctuations of ONOO- during the formation and remediation processes of DILI in the acetaminophen (APAP)-induced mouse model. Consequently, this work provides a promising tool for in-depth research of ONOO- associated pathological processes in DILI.

Quantum dots in noninvasive imaging of oral squamous cell carcinomas: A scoping literature review.

ABSTRACT: The current scoping review's objective was to outline existing applications, recent breakthroughs, and quantum dots' applicability in imaging of oral squamous cell cancer. Quantum dots are nanometric semiconductor crystals with customizable optical characteristics and intense, stable fluorescence suited for bioimaging and labeling. We used the Preferred reporting items for systematic reviews and meta-analyses (PRISMA) recommendations for conducting our systematic search. An analysis of the properties and applications of quantum dots in noninvasive detection of oral squamous cell cancer is presented in this study, which comprehensively explores the available evidence. Following searches in the databases PubMed, Ovid SP, and Cochrane using the search terms quantum dots AND oral squamous cell cancer, 55 published publications were chosen for this review. The review identified a total of eight papers that met the criteria. In noninvasive detection of oral squamous cell carcinoma, quantum dots have the potential to offer an array of therapeutic and diagnostic applications. Furthermore, quantum dots emit near-infrared and visible light, which is advantageous in biological imaging since it reduces light dispersion and absorption of tissue. The future may see quantum dots become a popular noninvasive imaging technique for oral squamous cell cancer. The number of studies accessible is quite limited, and further research is required.