Rational Design of an Activatable Near-Infrared Fluorogenic Platform for In Vivo Orthotopic Tumor Imaging and Resection.

Rational and effective design of a universal near-infrared (NIR) light-absorbed platform employed to prepare diverse activatable NIR fluorogenic probes for in vivo imaging and the imaging-guided tumor resection remains less exploited but highly meaningful. Herein, mandelic acid with a core structure of 4-hydroxylbenzyl alcohol to link recognition unit, a fluorophore and a quencher was employed to prepare activatable probes. We exemplified ester as carboxylesterase (CE)-recognized unit, ferrocene as quencher and phenothiazinium as NIR fluorophore to afford fluorogenic probes termed NBS-Fe-CE and NBS-C-Fe-CE. These probes enabled the conversion toward CE with significant fluorescence increases and successfully discriminate CE activity in cells. NIR light enhances the tumor penetration and enable imaging-guided orthotopic tumor resection. This specific case demonstrated that this platform can be effectively used to construct diverse NIR probes for imaging analytes in biological systems.

Progression in Near-Infrared Fluorescence Imaging Technology for Lung Cancer Management.

Lung cancer is a major threat to human health and a leading cause of death. Accurate localization of tumors in vivo is crucial for subsequent treatment. In recent years, fluorescent imaging technology has become a focal point in tumor diagnosis and treatment due to its high sensitivity, strong selectivity, non-invasiveness, and multifunctionality. Molecular probes-based fluorescent imaging not only enables real-time in vivo imaging through fluorescence signals but also integrates therapeutic functions, drug screening, and efficacy monitoring to facilitate comprehensive diagnosis and treatment. Among them, near-infrared (NIR) fluorescence imaging is particularly prominent due to its improved in vivo imaging effect. This trend toward multifunctionality is a significant aspect of the future advancement of fluorescent imaging technology. In the past years, great progress has been made in the field of NIR fluorescence imaging for lung cancer management, as well as the emergence of new problems and challenges. This paper generally summarizes the application of NIR fluorescence imaging technology in these areas in the past five years, including the design, detection principles, and clinical applications, with the aim of advancing more efficient NIR fluorescence imaging technologies to enhance the accuracy of tumor diagnosis and treatment.

Making the effect visible - OX40 targeting nanobodies for in vivo imaging of activated T cells.

Purpose: Human OX40 (hOX40/CD134), a member of the TNF receptor superfamily, is mainly expressed on activated T lymphocytes. Triggered by its ligand OX40L (CD252), it provides costimulatory signals that support the differentiation, proliferation and long-term survival of T cells. Besides being a relevant therapeutic target, hOX40 is also an important biomarker for monitoring the presence or infiltration of activated T cells within the tumor microenvironment (TME), the inflammatory microenvironment (IME) in immune-mediated diseases (IMIDs) and the lymphatic organs. Here, we developed novel single domain antibodies (nanobodies, Nbs) targeting hOX40 to monitor the activation status of T cells by in vivo molecular imaging. Methods: Nbs against hOX40 (hOX40-Nbs) were selected from an immunized Nb-library by phage display. The identified hOX40-Nbs were characterized in vitro, including determination of their specificity, affinity, stability, epitope recognition and their impact on OX40 signaling and T cell function. A lead candidate was site-specifically conjugated with a fluorophore via sortagging and applied for noninvasive in vivo optical imaging (OI) of hOX40-expressing cells in a xenograft mouse model. Results: Our selection campaign revealed four unique Nbs that exhibit strong binding affinities and high stabilities under physiological conditions. Epitope binning and domain mapping indicated the targeting of at least two different epitopes on hOX40. When analyzing their impact on OX40 signaling, an agonistic effect was excluded for all validated Nbs. Incubation of activated T cells with hOX40-Nbs did not affect cell viability or proliferation patterns, whereas differences in cytokine release were observed. In vivo OI with a fluorophore-conjugated lead candidate in experimental mice with hOX40-expressing xenografts demonstrated its specificity and functionality as an imaging probe. Conclusion: Considering the need for advanced probes for noninvasive in vivo monitoring of T cell activation dynamics, we propose, that our hOX40-Nbs have a great potential as imaging probes for noninvasive and longitudinal in vivo diagnostics. Quantification of OX40+ T cells in TME or IME will provide crucial insights into the activation state of infiltrating T cells, offering a valuable biomarker for assessing immune responses, predicting treatment efficacy, and guiding personalized immunotherapy strategies in patients with cancer or IMIDs.

High-sensitivity and spatial resolution benchtop cone beam XFCT imaging system with pixelated photon counting detectors using enhanced multipixel events correction method.

Objective.High atomic number element nanoparticles have shown potential in tumor diagnosis and therapy. X-ray fluorescence computed tomography (XFCT) technology enables quantitative imaging of high atomic number elements by specifically detecting characteristic x-ray signals. The potential for further biomedical applications of XFCT depends on balancing sensitivity, spatial resolution, and imaging speed in existing XFCT imaging systems.Approach.In this study, we utilized a high-energy resolution pixelated photon-counting detector for XFCT imaging. We tackled degradation caused by multi-pixel events in the photon-counting detector through energy and interaction position corrections. Sensitivity and spatial resolution imaging experiments were conducted using PMMA phantoms to validate the effectiveness of the multi-pixel events correction algorithm.Main results.After correction, the system's sensitivity and spatial resolution have both improved. Furthermore, XFCT/CBCT dual-modality imaging of gadolinium nanoparticles within mice subcutaneous tumor was successfully achieved.Significance.These results demonstrate the preclinical research application potential of the XFCT/CBCT dual-modality imaging system in high atomic number nanoparticle-based tumor diagnosis and therapy.

In Vivo Imaging Techniques for the Human Scalp: A Systematic Review of the Literature.

OBJECTIVE: Scalp inflammation and alopecia are distressing conditions for which patients regularly present to dermatology. Although some diagnoses can be made clinically, others require biopsy, which carries the risk of pain, infection, bleeding, and scarring. This review examines the existing literature regarding noninvasive in vivo imaging techniques and their evidence and utility in evaluating scalp pathology, with a focus on the diagnostics of hair conditions. METHODS: A systematic literature search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines without timeframe restrictions. The PubMed and Clarivate (Web of Science) databases were searched using the terms ("imaging" OR "in-vivo imaging" OR "non-invasive imaging" OR "non-invasive in vivo imaging" "imaging," "in-vivo imaging) AND ("human scalp disorders" OR "scalp" OR "hair loss" OR "alopecia"). Peer-reviewed randomized control trials (RCTs), prospective studies, retrospective studies, and case series or reports discussing in vivo imaging of the scalp published before 2022 were selected. RESULTS: Forty-two studies were included and discussed; modalities included laser devices (n = 27), ultrasound (US) (n = 13), infrared thermography (n = 1), skin capacitance imaging (SCI), and ultraviolet light-enhanced visualization (ULEV) (n = 1). The most common laser devices used were reflectance confocal microscopy (RCM), multiphoton microscopy (MPM), and optical coherence tomography (OCT). US techniques included high-frequency US (HFUS) and US biomicroscopy (UBM). CONCLUSION: Quality imaging of the scalp in the setting of alopecic, neoplastic, and inflammatory diseases is highly sought after. Many of these noninvasive imaging techniques show promise, each with individual advantages and disadvantages in imaging-specific conditions. Ultimately, noninvasive imaging techniques may be used to optimize patient management and minimize morbidity associated with scalp biopsies.

A portable photoacoustic microscopy and ultrasound system for rectal cancer imaging.

Photoacoustic microscopy offers functional information regarding tissue vasculature while ultrasound characterizes tissue structure. Combining these two modalities provides novel clinical applications including response assessment among rectal cancer patients undergoing therapy. We have previously demonstrated the capabilities of a co-registered photoacoustic and ultrasound device in vivo, but multiple challenges limited broad adoption. In this paper, we report significant improvements in an acoustic resolution photoacoustic microscopy and ultrasound (ARPAM/US) system characterized by simulation and phantom study, focusing on resolution, optical coupling, and signal characteristics. In turn, higher in-probe optical coupling efficiency, higher signal-to-noise ratio, higher data throughput, and better stability with minimal maintenance requirements were all accomplished. We applied the system to 19 ex vivo resected colorectal cancer samples and found significantly different signals between normal, cancer, and post-treatment tumor tissues. Finally, we report initial results of the first in vivo imaging study.

Transplanted Murine Tumours SPECT Imaging with 99mTc Delivered with an Artificial Recombinant Protein.

99mTc is a well-known radionuclide that is widely used and readily available for SPECT/CT (Single-Photon Emission Computed Tomography) diagnosis. However, commercial isotope carriers are not specific enough to tumours, rapidly clear from the bloodstream, and are not safe. To overcome these limitations, we suggest immunologically compatible recombinant proteins containing a combination of metal binding sites as 99mTc chelators and several different tumour-specific ligands for early detection of tumours. E1b protein containing metal-binding centres and tumour-specific ligands targeting integrin αvß3 and nucleolin, as well as a short Cys-rich sequence, was artificially constructed. It was produced in E. coli, purified by metal-chelate chromatography, and used to obtain a complex with 99mTc. This was administered intravenously to healthy Balb/C mice at an activity dose of about 80 MBq per mouse, and the biodistribution was studied by SPECT/CT for 24 h. Free sodium 99mTc-pertechnetate at the same dose was used as a reference. The selectivity of 99mTc-E1b and the kinetics of isotope retention in tumours were then investigated in experiments in C57Bl/6 and Balb/C mice with subcutaneously transplanted lung carcinoma (LLC) or mammary adenocarcinoma (Ca755, EMT6, or 4T1). The radionuclide distribution ratio in tumour and adjacent normal tissue (T/N) steadily increased over 24 h, reaching 15.7 ± 4.2 for EMT6, 16.5 ± 3.8 for Ca755, 6.7 ± 4.2 for LLC, and 7.5 ± 3.1 for 4T1.

Establishment of a visualized mouse orthotopic xenograft model of nasopharyngeal carcinoma.

Mouse orthotopic xenograft tumor models are commonly employed in studies investigating the mechanisms underlying the development and progression of tumors and their preclinical treatment. However, the unavailability of mature and visualized orthotopic xenograft models of nasopharyngeal carcinoma limits the development of treatment strategies for this cancer. The aim of this study was to provide a simple and reliable method for building an orthotopic xenograft model of nasopharyngeal carcinoma. Human nasopharyngeal carcinoma (C666-1-luc) cells, stably expressing the firefly luciferase gene, were injected subcutaneously into the right axilla of BALB/C nude mice. Four weeks later, the resulting subcutaneous tumors were cut into small blocks and grafted into the nasopharynx of immunodeficient BALB/C nude mice to induce tumor formation. Tumor growth was monitored by bioluminescence imaging and small animal magnetic resonance imaging (MRI). The expression of histological and immunological antigens associated with orthotopic xenograft nasopharyngeal carcinoma was analyzed by tissue section analysis and immunohistochemistry (IHC). A visualized orthotopic xenograft nasopharyngeal carcinoma model was successfully developed in this study. Luminescence signal detection, micro-MRI, and hematoxylin and eosin staining revealed the successful growth of tumors in the nasopharynx of the nude mice. Moreover, IHC analysis detected cytokeratin (CK), CK5/6, P40, and P63 expression in the orthotopic tumors, consistent with the reported expression of these antigens in human nasopharyngeal tumors. This study established a reproducible, visual, and less lethal orthotopic xenograft model of nasopharyngeal carcinoma, providing a platform for preclinical research.

Real-time in vivo confocal laser endomicroscopic imaging of equine endometrium: Preliminary observations and feasibility study.

Endometrial health is vital for the reproductive efficiency of broodmares and accurate diagnostic testing is crucial for directing the best treatment options and outcomes. Confocal laser endomicroscopy (CLE) is an endoscopic technique for obtaining in-vivo, real-time microscopic imaging of tissues using a fiber optic probe. CLE relies on induced tissue fluorescence and fluorescein sodium, given intravenously, is the contrast agent most used in human medicine. This study aimed to determine the feasibility of CLE for imaging equine endometrium and determine a standard dose of fluorescein sodium to achieve optimal cellular imaging. In-vivo CLE was performed on 44 mares, and the images were compared with routine histopathological analysis of endometrial biopsies. No adverse reactions occurred after IV fluorescein sodium administration and a dose of 4 mg/kg was established (0.04 mL/kg of 10 % fluorescein sodium solution) to achieve optimal image contrast. CLE enabled multiple regions of the endometrium to be assessed quickly. Distinct tissue architecture patterns could be appreciated using CLE, and the luminal epithelium could be assessed for integrity (ulceration) and exocytosed inflammatory cells. Endometrial gland distribution, density, shape, and epithelial height were evaluated. Blood vessels were clearly outlined, and inflammatory cells and fibrosis were discernable within the interstitium. Image quality varied between mares, and the stage of oestrous cycle may have been a factor of influence. This novel imaging modality enables collection of "virtual" biopsies and facilitates critical assessment of multiple regions of the uterus compared with the standard histopathologic assessment of a single random tissue biopsy.

Tetrandrine activates STING/TBK1/IRF3 pathway to potentiate anti-PD-1 immunotherapy efficacy in non-small cell lung cancer.

The efficacy of PD-1 therapy in non-small cell lung cancer (NSCLC) patients remains unsatisfactory. Activating the STING pathway is a promising strategy to improve PD-1 inhibitor efficacy. Here, we found tetrandrine (TET), an anti-tumor compound extracted from a medicinal plant commonly used in traditional Chinese medicine, has the ability to inhibit NSCLC tumor growth. Mechanistically, TET induces nuclear DNA damage and increases cytosolic dsDNA, thereby activating the STING/TBK1/IRF3 pathway, which in turn promotes the tumor infiltration of dendritic cells (DCs), macrophages, as well as CD8+ T cells in mice. In vivo imaging dynamically monitored the increased activity of the STING pathway after TET treatment and predicted the activation of the tumor immune microenvironment. We further revealed that the combination of TET with αPD-1 monoclonal antibody (αPD-1 mAb) yields significant anti-cancer effects by promoting CD8+ T cell infiltration and enhancing its cell-killing effect, which in turn reduced the growth of tumors and prolonged survival of NSCLC mice. Therefore, TET effectively eliminates NSCLC cells and enhances immunotherapy efficacy through the activation of the STING pathway, and combining TET with anti-PD-1 immunotherapy deserves further exploration for applications.

Inflammatory response toward a Mg-based metallic biomaterial implanted in a rat femur fracture model.

The immune system plays an important role in fracture healing, by modulating the pro-inflammatory and anti-inflammatory responses occurring instantly upon injury. An imbalance in these responses can lead to adverse outcomes, such as non-union of fractures. Implants are used to support and stabilize complex fractures. Biodegradable metallic implants offer the potential to avoid a second surgery for implant removal, unlike non-degradable implants. However, considering our dynamic immune system it is important to conduct in-depth studies on the immune response to these implants in living systems. In this study, we investigated the immune response to Mg and Mg-10Gd in vivo in a rat femur fracture model with external fixation. In vivo imaging using liposomal formulations was used to monitor the fluorescence-related inflammation over time. We combine ex vivo methods with our in vivo study to evaluate and understand the systemic and local effects of the implants on the immune response. We observed no significant local or systemic effects in the Mg-10Gd implanted group compared to the SHAM and Mg implanted groups over time. Our findings suggest that Mg-10Gd is a more compatible implant material than Mg, with no adverse effects observed in the early phase of fracture healing during our 4-week study. STATEMENT OF SIGNIFICANCE: Degradable metallic implants in form of Mg and Mg-10Gd intramedullary pins were assessed in a rat femur fracture model, alongside a non-implanted SHAM group with special respect to the potential to induce an inflammatory response. This pre-clinical study combines innovative non-invasive in vivo imaging techniques associated with multimodal, ex vivo cellular and molecular analytics. The study contributes to the development and evaluation of degradable biometals and their clinical application potential. The study results indicate that Mg-10Gd did not exhibit any significant harmful effects compared to the SHAM and Mg groups.

Half-Curcumin-Based Chemiluminescence Probes and Their Applications in Detecting Quasi-Stable Oxidized Proteins.

Numerous methods have been reported for detecting ROS/RNS in vitro and in vivo; however, detecting methods for the secondary products of the reactive oxygen species (ROS)/reactive nitrogen species (RNS) reactions, particularly quasi-stable oxidized products, have been much less explored. In this report, we observed that half-curcumins could generate chemiluminescence (CL). In contrast to other chemiluminescence scaffolds, the distinguishing feature of a half-curcumin is the formation of a carbanion intermediate of its acetylacetone moiety, opening unique avenues for applications. In this study, we designed a series of half-curcumins CRANAD-Xs and found that CRANAD-164 could be used to detect quasi-stable oxidized proteins (QSOP) in vivo and in patient serum samples. We illustrated that CRANAD-164 could be used to monitor the responses of taurine, an amino acid with newly reported anti-aging capacity, in an inflammatory mouse model. Remarkably, we further demonstrated that the QSOP levels were much higher in the disease serum samples, including Alzheimer's disease (AD), compared to the samples from healthy controls. Moreover, our results revealed that the sera chemiluminescence intensities were higher in aged healthy controls compared to young healthy subjects, suggesting that CRANAD-164 can be used to monitor the increase of QSOP during aging.

Hard X-ray imaging and tomography at the Biomedical Imaging and Therapy beamlines of Canadian Light Source.

The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X-ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high-resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X-ray imaging techniques available to users.

[In vivo tumor imaging and therapy based on near-infrared cadmium-free quantum dots].

Near-infrared fluorescence imaging technology, which possesses superior advantages including real-time and fast imaging, high spatial and temporal resolution, and deep tissue penetration, shows great potential for tumor imaging in vivo and therapy. Ⅰ-Ⅲ-Ⅵ quantum dots exhibit high brightness, broad excitation, easily tunable emission wavelength and superior stability, and do not contain highly toxic heavy metal elements such as cadmium or lead. These advantages make Ⅰ-Ⅲ-Ⅵ quantum dots attract widespread attention in biomedical field. This review summarizes the recent advances in the controlled synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots and their applications in tumor imaging in vivo and therapy. Firstly, the organic-phase and aqueous-phase synthesis of Ⅰ-Ⅲ-Ⅵ quantum dots as well as the strategies for regulating the near-infrared photoluminescence are briefly introduced; secondly, representative biomedical applications of near-infrared-emitting cadmium-free quantum dots including early diagnosis of tumor, lymphatic imaging, drug delivery, photothermal and photodynamic therapy are emphatically discussed; lastly, perspectives on the future directions of developing quantum dots for biomedical application and the faced challenges are discussed. This paper may provide guidance and reference for further research and clinical translation of cadmium-free quantum dots in tumor diagnosis and treatment.

The influence of various polymer coatings on the in vitro and in vivo properties of PLGA nanoparticles: Comprehensive study.

Nanoparticles based on poly(lactic-co-glycolic acid) (PLGA) with various surface chemistry are widely used in biomedicine for theranostic applications. The nature of the external coating of nanoparticles has a significant influence on their efficiency as drug carriers or visualization agents. However, information about the mechanisms of nanoparticle accumulation in tumors and the influence of their surface properties on biodistribution is scarce due to the lack of systematic evaluation. Here we investigate the effect of different polymer coatings of the surface on in vitro and in vivo properties of PLGA nanoparticles. Namely, cell binding efficiency, cytotoxicity, efficiency of fluorescent bioimaging, and tumor accumulation were tested. The highest binding efficiency in vitro and cytotoxicity were observed for positively charged polymers. Interestingly, in vivo fluorescent visualization of tumor-bearing mice and quantitative measurements of biodistribution of magnetite-loaded nanoparticles indicated different dependences of accumulation in tumors on the coating of PLGA nanoparticles. This means that nanoparticle surface properties can simultaneously enhance imaging efficiency and decrease quantitative accumulation in tumors. The obtained data demonstrate the complexity of the dependence of nanoparticles' effectiveness for theranostic applications on surface features. We believe that this study will contribute to the rational design of nanoparticles for effective cancer diagnostics and therapy.

Assessment of tissue response in vivo: PET-CT imaging of titanium and biodegradable magnesium implants.

To study in vivo the bioactivity of biodegradable magnesium implants and other possible biomaterials, we are proposing a previously unexplored application of PET-CT imaging, using available tracers to follow soft tissue and bone remodelling and immune response in the presence of orthopaedic implants. Female Wistar rats received either implants (Ti6Al7Nb titanium or WE43 magnesium) or corresponding transcortical sham defects into the diaphyseal area of the femurs. Inflammatory response was followed with [18F]FDG and osteogenesis with [18F]NaF, over the period of 1.5 months after surgery. An additional pilot study with [68Ga]NODAGA-RGD tracer specific to αvß3 integrin expression was performed to follow the angiogenesis for one month. [18F]FDG tracer uptake peaked on day 3 before declining in all groups, with Mg and Ti groups exhibiting overall higher uptake compared to sham. This suggests increased cellular activity and tissue response in the presence of Mg during the initial weeks, with Ti showing a subsequent increase in tracer uptake on day 45, indicating a foreign body reaction. [18F]NaF uptake demonstrated the superior osteogenic potential of Mg compared to Ti, with peak uptake on day 7 for all groups. [68Ga]NODAGA-RGD pilot study revealed differences in tracer uptake trends between groups, particularly the prolonged expression of αvß3 integrin in the presence of implants. Based on the observed differences in the uptake trends of radiotracers depending on implant material, we suggest that PET-CT is a suitable modality for long-term in vivo assessment of orthopaedic biomaterial biocompatibility and underlying tissue reactions. STATEMENT OF SIGNIFICANCE: The study explores the novel use of positron emission tomography for the assessment of the influence that biomaterials have on the surrounding tissues. Previous related studies have mostly focused on material-related effects such as implant-associated infections or to follow the osseointegration in prosthetics, but the use of PET to evaluate the materials has not been reported before. The approach tests the feasibility of using repeated PET-CT imaging to follow the tissue response over time, potentially improving the methodology for adopting new biomaterials for clinical use.

Glyoxal-methyl-ethylene sulfonic acid fixative enhances the fixation of cytoskeletal structures for Förster resonance energy transfer measurements.

Förster resonance energy transfer (FRET) serves as a tool for measuring protein-protein interactions using various sensor molecules. The tension sensor module relies on FRET technology. In our study, this module was inserted within the actinin molecule to measure the surface tension of the cells. Given that the decay curve of FRET efficiency correlates with surface tension increase, precise and accurate efficiency measurement becomes crucial. Among the methods of FRET measurements, FRET efficiency remains the most accurate if sample fixation is successful. However, when cells were fixed with 4% paraformaldehyde (PFA), the actinin-FRET sensor diffused across the cytoplasm; this prompted us to explore fixation method enhancements. Glyoxal fixative has been reported to improve cytoskeletal morphologies compared to PFA. However, it was not known whether glyoxal fits FRET measurements. Glyoxal necessitates an acetic acid solution for fixation; however, acidic conditions could compromise fluorescence stability. We observed that the pH working range of glyoxal fixative aligns closely with MES (methyl-ethylene sulfonic acid) Good's buffer. Initially, we switched the acidic solution for MES buffer and optimized the fixation procedure for in vitro and in vivo FRET imaging. By comparing FRET measurements on hydrogels with known stiffness to tumor nodules in mouse lung, we estimated in vivo stiffness. The estimated stiffness of cancerous tissue was harder than the reported stiffness of smooth muscle. This discovery shed lights on how cancer cells perceive environmental stiffness during metastasis.

A transformable and self-oxygenated smart probe for enhanced tumor sonodynamic therapy.

Sonodynamic therapy (SDT) is emerging as a promising modality for cancer treatment. However, improving the tumor bioavailability and anti-hypoxia capability of sonosensitizers faces a big challenge. In this work, we present a tumor microenvironment (TME)-mediated nanomorphology transformation and oxygen (O2) self-production strategy to enhance the sonodynamic therapeutic efficacy of tumors. A smart probe Ce6-Leu@Mn2+ that consists of a glutathione (GSH) and leucine amino peptidase (LAP) dual-responsive unit, a 2-cyanobenzothiazole (CBT) group, and a Mn2+-chelated Ce6 as sonosensitizer for tumor SDT was synthesized, and its SDT potential for liver tumor HepG2 in living mice was systematically studied. It was found that the probes could self-assemble into large nanoparticles in physiological condition and spontaneously transformed into small particles under the dual stimulation of GSH and LAP in TME resulting in enhanced tumor accumulation and deep penetration. More notably, Ce6-Leu@Mn2+ could convert endogenous hydrogen peroxide to O2, thereby alleviating the hypoxia and achieving effective SDT against hypoxic tumors under the excitation of ultrasound. We thus believe this smart TME-responsive probe may provide a noninvasive and efficient means for malignant tumor treatment. STATEMENT OF SIGNIFICANCE: Sonodynamic therapy (SDT) is emerging as a promising therapeutic modality for cancer treatment. However, how to improve the tumor bioavailability and anti-hypoxia capability of sonosensitizers remains a huge challenge. Herein, we rationally developed a theranostic probe Ce6-Leu@Mn2+ that can transform into small-size nanoparticles from initial large particles under the dual stimulation of LAP and GSH in tumor microenvironment (TME) resulting in enhanced tumor accumulation, deep tissue penetration as well as remarkable O2 self-production for enhanced sonodynamic therapy of human liver HepG2 tumor in living mice. This smart TME-responsive probe may provide a noninvasive and efficient means for hypoxic tumor treatment.

Microscope-integrated optical coherence tomography for in vivo human brain tumor detection with artificial intelligence.

OBJECTIVE: It has been shown that optical coherence tomography (OCT) can identify brain tumor tissue and potentially be used for intraoperative margin diagnostics. However, there is limited evidence on its use in human in vivo settings, particularly in terms of its applicability and accuracy of residual brain tumor detection (RTD). For this reason, a microscope-integrated OCT system was examined to determine in vivo feasibility of RTD after resection with automated scan analysis. METHODS: Healthy and diseased brain was 3D scanned at the resection edge in 18 brain tumor patients and investigated for its informative value in regard to intraoperative tissue classification. Biopsies were taken at these locations and labeled by a neuropathologist for further analysis as ground truth. Optical OCT properties were obtained, compared, and used for separation with machine learning. In addition, two artificial intelligence-assisted methods were utilized for scan classification, and all approaches were examined for RTD accuracy and compared to standard techniques. RESULTS: In vivo OCT tissue scanning was feasible and easily integrable into the surgical workflow. Measured backscattered light signal intensity, signal attenuation, and signal homogeneity were significantly distinctive in the comparison of scanned white matter to increasing levels of scanned tumor infiltration (p < 0.001) and achieved high values of accuracy (85%) for the detection of diseased brain in the tumor margin with support vector machine separation. A neuronal network approach achieved 82% accuracy and an autoencoder approach 85% accuracy in the detection of diseased brain in the tumor margin. Differentiating cortical gray matter from tumor tissue was not technically feasible in vivo. CONCLUSIONS: In vivo OCT scanning of the human brain has been shown to contain significant value for intraoperative RTD, supporting what has previously been discussed for ex vivo OCT brain tumor scanning, with the perspective of complementing current intraoperative methods for this purpose, especially when deciding to withdraw from further resection toward the end of the surgery.

A Comprehensive Exploration of Caspase Detection Methods: From Classical Approaches to Cutting-Edge Innovations.

The activation of caspases is a crucial event and an indicator of programmed cell death, also known as apoptosis. These enzymes play a central role in cancer biology and are considered one promising target for current and future advancements in therapeutic interventions. Traditional methods of measuring caspase activity such as antibody-based methods provide fundamental insights into their biological functions, and are considered essential tools in the fields of cell and cancer biology, pharmacology and toxicology, and drug discovery. However, traditional methods, though extensively used, are now recognized as having various shortcomings. In addition, these methods fall short of providing solutions to and matching the needs of the rapid and expansive progress achieved in studying caspases. For these reasons, there has been a continuous improvement in detection methods for caspases and the network of pathways involved in their activation and downstream signaling. Over the past decade, newer methods based on cutting-edge state-of-the-art technologies have been introduced to the biomedical community. These methods enable both the temporal and spatial monitoring of the activity of caspases and their downstream substrates, and with enhanced accuracy and precision. These include fluorescent-labeled inhibitors (FLIs) for live imaging, single-cell live imaging, fluorescence resonance energy transfer (FRET) sensors, and activatable multifunctional probes for in vivo imaging. Recently, the recruitment of mass spectrometry (MS) techniques in the investigation of these enzymes expanded the repertoire of tools available for the identification and quantification of caspase substrates, cleavage products, and post-translational modifications in addition to unveiling the complex regulatory networks implicated. Collectively, these methods are enabling researchers to unravel much of the complex cellular processes involved in apoptosis, and are helping generate a clearer and comprehensive understanding of caspase-mediated proteolysis during apoptosis. Herein, we provide a comprehensive review of various assays and detection methods as they have evolved over the years, so to encourage further exploration of these enzymes, which should have direct implications for the advancement of therapeutics for cancer and other diseases.