Prof. Vasilis Ntziachristos, Msc PhD
Director, Institute for Biological and Medical Imaging and Director, Bioengineering DepartmentOur research at Helmholtz Munich is driven by our interest to provide solutions that address critical unmet medical need and positively impact healthcare and the well-being of society.
Our research at Helmholtz Munich is driven by our interest to provide solutions that address critical unmet medical need and positively impact healthcare and the well-being of society.
Academic Career and Research Areas
Vasilis Ntziachristos’ research focuses on the development of new methods for advancing well-being and accelerating discovery. His focus is the development of novel methods for prevention and early detection of disease, also serving as the means of administering more efficient treatment. His expertise span the fields of imaging, sensing and computation and his activities cover the entire spectrum from theoretical and methodological developments and basic discovery to clinical translation and entrepreneurship. Examples of his work involve the development of Fluorescent Molecular Imaging as means to improve guidance in surgery and the performance of diagnostic endoscopy as well as the development of Optoacoustic Imaging and Microscopy methods for advancing discovery and impacting healthcare. He is the founder of several companies including SurgVision BV which commercializes fluorescence imaging solutions for surgery, now under Bracco SpA, and iThera Medical GmbH, a company that commercializes optoacoustic technology.
Professor Vasilis Ntziachristos studied electrical engineering at Aristotle University in Thessaloniki. Following his M.Sc. and Ph.D. in the Department of Bioengineering at the University of Pennsylvania, he was then appointed Assistant Professor and Director of the Laboratory for Bio-Optics and Molecular Imaging at Harvard University and Massachusetts General Hospital. Since 2007, he has served as Professor of Medicine and Electrical Engineering and the Chair of Biological Imaging at the Technical University of Munich and Director of the Institute of Biological and Medical Imaging at Helmholtz Munich. Prof. Ntziachristos is also currently Director of Bioengineering at the Helmholtz Pioneer Campus and the Head of the Bioengineering Department at Helmholtz Munich.
Fields of Work and Expertise
Biomedical Engineering PhotonicsImagingMicroscopyOptoacousticsClinical Translation Computational Methods Machine Learning
Data Analytics Biological Engineering
Professional Background
Instructor, Harvard University and Massachusetts General Hospital
Assistant Professor and Director of the Laboratory of Bio-optics and Molecular Imaging, Harvard University and Massachusetts General Hospital
Full Professor C4/W3 of Medicine and Electrical Engineering, Chair of Biological Imaging at the Technical University of Munich Director, Institute for Biological and Medical Imaging
Publications
Read more2025 Scientific Article in Acta Biomaterialia
Photoswitching protein-XTEN fusions as injectable optoacoustic probes.
Optoacoustic imaging (OAI) is a unique in vivo imaging technique combining deep tissue penetration with high resolution and molecular sensitivity. OAI relying on strong intrinsic contrast, such as blood hemoglobin, already shows its value in medical diagnostics. However, OAI sensitivity to current extrinsic contrast agents is insufficient and limits its role in detecting disease-related biomarkers. The recently introduced concept of photoswitching and temporal unmixing techniques for OAI allows detecting extrinsic contrast with high sensitivity, allowing the visualization of small populations of cells labeled with photoswitching proteins deep within the tissue. However, transgene modification might not be permitted in some cases, such as for diagnostic use. Therefore, it is desirable to leverage the concept of photoswitching OAI towards injectable formulations. Since photoswitchable synthetic dyes are mainly excited by blue wavelengths unsuited for imaging in tissue, we propose exploiting the addition of XTENs to photoswitching proteins towards yielding injectable agents. The addition of XTEN to a protein enhances its plasma half-life and bioavailability, thus allowing its use, for example, in targeted labeling approaches. In this pilot study, we show that intravenously injected near-infrared absorbing photoswitchable proteins, ReBphP-PCM, coupled to XTEN, allow highly sensitive optoacoustic visualization of a tumor xenograft in vivo. The sensitivity to XTENs-ReBphP-PCM determined by ex vivo analysis of labeled cells is one to two orders of magnitude beyond conventional synthetic dyes used currently in OAI. The enhanced sensitivity afforded by photoswitching OAI, in combination with the increased bioavailability and biocompatibility of XTENs-ReBphP-PCM, makes this fusion protein a promising tool for facilitating sensitive detection of biomarkers in OAI with a potential for future use in diagnostics. STATEMENT OF SIGNIFICANCE: Optoacoustic imaging (OAI) is a unique in vivo imaging technique that combines deep tissue penetration with high resolution. OAI, which relies on intrinsic contrast, such as blood hemoglobin, could already be valuable in medical diagnostics. However, the use of extrinsic contrast agents to augment disease-related biomarkers in research and diagnostics suffers from very limited sensitivity of the generated contrast agent. We present an intravenously injected photoswitchable protein, ReBphP-PCM, coupled to XTEN, allowing highly sensitive OAI. The sensitivity is one to two orders of magnitude greater than that of conventional synthetic dyes used currently in OA imaging. The high sensitivity afforded by photoswitching together with the enhanced bioavailability and biocompatibility of the XTENs-ReBphP-PCM make this a standard agent for high-quality detection of OAI with potential for clinical use.
A primer on current status and future opportunities of clinical optoacoustic imaging.
Despite its introduction in the 1970’s, it is only recent technology advances that have propelled growth in clinical optoacoustic (photoacoustic) imaging over the past decade. We analytically present the broad landscape of clinical optoacoustic applications in the context of these key technology advances, the unique contrast achieved, and the tissue biomarkers resolved. We then discuss current challenges and future opportunities to address the unmet clinical needs.
2025 Scientific Article in Redox Biology
Radiosensitizing capacity of fenofibrate in glioblastoma cells depends on lipid metabolism.
Despite advances in multimodal therapy approaches such as resection, chemotherapy and radiotherapy, the overall survival of patients with grade 4 glioblastoma (GBM) remains extremely poor (average survival time <2 years). Altered lipid metabolism, which increases fatty acid synthesis and thereby contributes to radioresistance in GBM, is a hallmark of cancer. Therefore, we explored the radiosensitizing effect of the clinically approved, lipid-lowering drug fenofibrate (FF) in different GBM cell lines (U87, LN18). Interestingly, FF (50 μM) significantly radiosensitizes U87 cells by inducing DNA double-strand breaks through oxidative stress and impairing mitochondrial membrane integrity, but radioprotects LN18 cells by reducing the production of reactive oxygen species (ROS) and stabilizing the mitochondrial membrane potential. A comparative protein and lipid analysis revealed striking differences in the two GBM cell lines: LN18 cells exhibited a significantly higher membrane expression density of the fatty acid (FA) cluster protein transporter CD36 than U87 cells, a higher expression of glycerol-3-phosphate acyltransferase 4 (GPAT4) which supports the production of large lipid droplets (LDs), and a lower expression of diacylglycerol O-acyltransferase 1 (DGAT1) which regulates the formation of small LDs. Consequently, large LDs are predominantly found in LN18 cells, whereas small LDs are found in U87 cells. After a combined treatment of FF and irradiation, the number of large LDs significantly increased in radioresistant LN18 cells, whereas the number of small LDs decreased in radiosensitive U87 cells. The radioprotective effect of FF in LN18 cells could be associated with the presence of large LDs, which act as a sink for the lipophilic drug FF. To prevent uptake of FF by large LDs and to ameliorate its function as a radiosensitizer, FF was encapsulated in biomimetic cell membrane extracellular lipid vesicles (CmEVs) which alter the intracellular trafficking of the drug. In contrast to the free drug, CmEV-encapsulated FF was predominantly enriched in the lysosomal compartment, causing necrosis by impairing lysosomal membrane integrity. Since the stability of plasma and lysosomal membranes is maintained by the presence of the stress-inducible heat shock protein 70 (Hsp70) which has a strong affinity to tumor-specific glycosphingolipids, necrosis occurs predominantly in LN18 cells having a lower membrane Hsp70 expression density than U87 cells. In summary, our findings indicate that the lipid metabolism of tumor cells can affect the radiosensitizing capacity of FF when encountered either as a free drug or as a drug loaded in biomimetic lipid vesicles.
2025 Scientific Article in Journal of Biomedical Optics
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.
2024 Editorial in Nature Reviews Bioengineering
Addressing unmet clinical need with optoacoustic imaging.
Optoacoustic (photoacoustic) imaging has seen considerable growth in technological advances and clinical application over the past decade. This piece critically discusses whether optoacoustic imaging can become a mainstream clinical modality.
2024 Scientific Article in Photoacoustics
Multiscale optoacoustic assessment of skin microvascular reactivity in carotid artery disease.
Microvascular endothelial dysfunction may provide insights into systemic diseases, such as carotid artery disease. Raster-scan optoacoustic mesoscopy (RSOM) can produce images of skin microvasculature during endothelial dysfunction challenges via numerous microvascular features. Herein, RSOM was employed to image the microvasculature of 26 subjects (13 patients with single carotid artery disease, 13 healthy participants) to assess the dynamics of 18 microvascular features at three scales of detail, i.e., the micro- (<100 μm), meso- (≈100–1000 μm) and macroscale (<1000 μm), during post-occlusive reactive hyperemia challenges. The proposed analysis identified a subgroup of 9 features as the most relevant to carotid artery disease because they achieved the most efficient classification (AUC of 0.93) between the two groups in the first minute of hyperemia (sensitivity/specificity: 0.92/0.85). This approach provides a non-invasive solution to microvasculature quantification in carotid artery disease, a main form of cardiovascular disease, and further highlights the possible link between systemic disease and microvascular dysfunction.
2024 Scientific Article in Journal of Biophotonics
Hybrid Raman and partial wave spectroscopy microscope for the characterization of molecular and structural alterations in tissue.
We present a hybrid Raman spectroscopy (RS) and partial wave spectroscopy (PWS) microscope for the characterization of molecular and structural tissue alterations. The PWS performance was assessed with surface roughness standards, while the Raman performance with a silicon crystal standard. We also validated the system on stomach and intestinal mouse tissues, two closely-related tissue types, and demonstrate that the addition of PWS information improves RS data classification for these tissue types from R2 = 0.892 to R2 = 0.964 (norm of residuals 0.863 and 0.497, respectively). Then, in a proof-of-concept experiment, we show that the hybrid system can detect changes in intestinal tissues harvested from a tumorigenic Villin-Cre, Apcfl/wt mouse. We discuss how the hybrid modality offers new abilities to identify the relative roles of PWS morphological features and Raman molecular fingerprints, possibly allowing for their combination to enhance the study of carcinogenesis and early cancer diagnostics in the future.
2024 Review in Molecular Imaging and Biology
Neurotoxin-derived optical probes for elucidating molecular and developmental biology of neurons and synaptic connections : Toxin-derived optical probes for neuroimaging.
Botulinum neurotoxins (BoNTs) and tetanus toxin (TeTX) are the deadliest biological substances that cause botulism and tetanus, respectively. Their astonishing potency and capacity to enter neurons and interfere with neurotransmitter release at presynaptic terminals have attracted much interest in experimental neurobiology and clinical research. Fused with reporter proteins or labelled with fluorophores, BoNTs and TeTX and their non-toxic fragments also offer remarkable opportunities to visualize cellular processes and functions in neurons and synaptic connections. This study presents the state-of-the-art optical probes derived from BoNTs and TeTX and discusses their applications in molecular and synaptic biology and neurodevelopmental research. It reviews the principles of the design and production of probes, revisits their applications with advantages and limitations and considers prospects for future improvements. The versatile characteristics of discussed probes and reporters make them an integral part of the expanding toolkit for molecular neuroimaging, promoting the discovery process in neurobiology and translational neurosciences.
2024 Scientific Article in NPJ Cardiovascular Health
Intravascular ICG-enhanced NIRF-IVUS imaging to assess progressive atherosclerotic lesions in excised human coronary arteries.
Indocyanine green (ICG)-enhanced intravascular near-infrared fluorescence (NIRF) imaging enhances the information obtained with intravascular ultrasound (IVUS) by visualizing pathobiological characteristics of atherosclerotic plaques. To advance our understanding of this hybrid method, we aimed to assess the potential of NIRF-IVUS to identify different stages of atheroma progression by characterizing ICG uptake in human pathological specimens. After excision, 15 human coronary specimens from 13 adult patients were ICG-perfused and imaged with NIRF-IVUS. All specimens were then histopathologically and immunohistochemically assessed. NIRF-IVUS imaging revealed colocalization of ICG-deposition to plaque areas of lipid accumulation, endothelial disruption, neovascularization and inflammation. Moreover, ICG concentrations were significantly higher in advanced coronary artery disease stages (p < 0.05) and correlated significantly to plaque macrophage burden (r = 0.67). Current intravascular methods fail to detect plaque biology. Thus, we demonstrate how human coronary atheroma stage can be assessed based on pathobiological characteristics uniquely captured by ICG-enhanced intravascular NIRF.
Controlling the sound of light: photoswitching optoacoustic imaging.
Optoacoustic (photoacoustic) imaging advances allow high-resolution optical imaging much deeper than optical microscopy. However, while label-free optoacoustics have already entered clinical application, biological imaging is in need of ubiquitous optoacoustic labels for use in ways that are similar to how fluorescent proteins propelled optical microscopy. We review photoswitching advances that shine a new light or, in analogy, 'bring a new sound' to biological optoacoustic imaging. Based on engineered labels and novel devices, switching uses light or other energy forms and enables signal modulation and synchronous detection for maximizing contrast and detection sensitivity over other optoacoustic labels. Herein, we explain contrast enhancement in the spectral versus temporal domains and review labels and key concepts of switching and their properties to modulate optoacoustic signals. We further outline systems and applications and discuss how switching can enable optoacoustic imaging of cellular or molecular contrast at depths and resolutions beyond those of other optical methods.
2024 Scientific Article in Nature Communications
Bragg grating etalon-based optical fiber for ultrasound and optoacoustic detection.
Fiber-based interferometers receive significant interest as they lead to miniaturization of optoacoustic and ultrasound detectors without the quadratic loss of sensitivity common to piezoelectric elements. Nevertheless, in contrast to piezoelectric crystals, current fiber-based ultrasound detectors operate with narrow ultrasound bandwidth which limits the application range and spatial resolution achieved in imaging implementations. We port the concept of silicon waveguide etalon detection to optical fibers using a sub-acoustic reflection terminator to a Bragg grating embedded etalon resonator (EER), uniquely implementing direct and forward-looking access to incoming ultrasound waves. Precise fabrication of the terminator is achieved by continuously recording the EER spectrum during polishing and fitting the spectra to a theoretically calculated spectrum for the selected thickness. Characterization of the EER inventive design reveals a small aperture (10.1 µm) and an ultra-wide bandwidth (160 MHz) that outperforms other fiber resonators and enables an active detection area and overall form factor that is smaller by more than an order of magnitude over designs based on piezoelectric transducers. We discuss how the EER paves the way for the most adept fiber-based miniaturized sound detection today, circumventing the limitations of currently available designs.
2024 Scientific Article in Photoacoustics
Non-invasive optoacoustic imaging of dermal microcirculatory revascularization in diet-induced obese mice undergoing exercise intervention.
Microcirculatory dysfunction has been observed in the dermal white adipose tissue (dWAT) and subcutaneous white adipose tissue (scWAT) of obese humans and has been proposed as an early prediction marker for cardio-metabolic disease progression. In-vivo visualization and longitudinal monitoring of microvascular remodeling in these tissues remains challenging. We compare the performance of two optoacoustic imaging methods, i.e. multi-spectral optoacoustic tomography (MSOT) and raster-scanning optoacoustic mesoscopy (RSOM) in visualizing lipid and hemoglobin contrast in scWAT and dWAT in a mouse model of diet-induced obesity (DIO) undergoing voluntary wheel running intervention for 32 weeks. MSOT visualized lipid and hemoglobin contrast in murine fat depots in a quantitative manner even at early stages of DIO. We show for the first time to our knowledge that RSOM allows precise visualization of the dWAT microvasculature and provides quantitative readouts of skin layer thickness and vascular density in dWAT and dermis. Combination of MSOT and RSOM resolved exercise-induced morphological changes in microvasculature density, tissue oxygen saturation, lipid and blood volume content in dWAT and scWAT. The combination of MSOT and RSOM may allow precise monitoring of microcirculatory dysfunction and intervention response in dWAT and scWAT in a mouse model for DIO. Our findings have laid out the foundation for future clinical studies using optoacoustic-derived vascular readouts from adipose tissues as a biomarker for monitoring microcirculatory function in metabolic disease.
2024 Scientific Article in Journal of Controlled Release
Tuning the photophysical properties of cyanine by barbiturate functionalization and nanoformulation for efficient optoacoustics- guided phototherapy.
Cyanine derivatives are organic dyes widely used for optical imaging. However, their potential in longitudinal optoacoustic imaging and photothermal therapy remains limited due to challenges such as poor chemical stability, poor photostability, and low photothermal conversion. In this study, we present a new structural modification for cyanine dyes by introducing a strongly electron-withdrawing group (barbiturate), resulting in a new series of barbiturate-cyanine dyes (BC810, BC885, and BC1010) with suppressed fluorescence and enhanced stability. Furthermore, the introduction of BC1010 into block copolymers (PEG114-b-PCL60) induces aggregation-caused quenching, further boosting the photothermal performance. The photophysical properties of nanoparticles (BC1010-NPs) include their remarkably broad absorption range from 900 to 1200 nm for optoacoustic imaging, allowing imaging applications in NIR-I and NIR-II windows. The combined effect of these strategies, including improved photostability, enhanced nonradiative relaxation, and aggregation-caused quenching, enables the detection of optoacoustic signals with high sensitivity and effective photothermal treatment of in vivo tumor models when BC1010-NPs are administered before irradiation with a 1064 nm laser. This research introduces a barbiturate-functionalized cyanine derivative with optimal properties for efficient optoacoustics-guided theranostic applications. This new compound holds significant potential for biomedical use, facilitating advancements in optoacoustic-guided diagnostic and therapeutic approaches.
2024 Scientific Article in Angewandte Chemie - Internationale Edition
Merged molecular switches excel as optoacoustic dyes: Azobenzene-cyanines are loud and photostable NIR imaging agents.
Optoacoustic (or photoacoustic) imaging promises micron-resolution noninvasive bioimaging with much deeper penetration (>cm) than fluorescence. However, optoacoustic imaging of enzyme activity would require loud, photostable, NIR-absorbing molecular contrast agents: which remain unknown. Most organic molecular contrast agents are repurposed fluorophores, with severe shortcomings of photoinstability or phototoxicity under optoacoustic imaging, as consequences of their slow S1→S0 electronic relaxation. We now report that known fluorophores can be rationally modified to reach ultrafast S1→S0 rates, without much extra molecular complexity, simply by merging them with molecular switches. Here, we merge azobenzene switches to cyanine dyes to give ultrafast relaxation (<10 ps, >100-fold faster). Without even adapting instrument settings, these azohemicyanines display outstanding improvements in signal longevity (>1000-fold increase of photostability) and signal loudness (here: >3-fold even at time zero). We show why this simple but unexplored design strategy can still offer stronger performance in the future, and can also increase the spatial resolution and the quantitative linearity of photoacoustic response over extended longitudinal imaging. By bringing the world of molecular switches and rotors to bear on problems facing optoacoustic agents, this practical strategy will help to unleash the full potential of optoacoustic imaging in fundamental studies and translational uses.
Deep model-based optoacoustic image reconstruction (DeepMB).
Multispectral optoacoustic tomography requires real-time image feedback during clinical use. Herein, we present DeepMB, a deep learning framework to express the model-based reconstruction operator with a deep neural network and reconstruct high-quality optoacoustic images from arbitrary experimental input data at speeds that enable live imaging (31ms per image).
Multispectral optoacoustic imaging of peripheral nerve vascularization and morphology.
Imaging peripheral nerve morphology, function, and vascular supply is important in clinical medicine and research. In this work, we evaluate the imaging capabilities of multispectral optoacoustic tomography (MSOT) for peripheral nerves. We demonstrate how recent advances in MSOT data processing combined with data-driven unmixing overcome adverse effects of measurement noise and light fluence attenuation and provide detailed insights into the vasa nervorum and the internal structure of peripheral nerves.
2024 Scientific Article in IEEE Transactions on Medical Imaging
Performance assessment and quality control of fluorescence molecular endoscopy with a multi-parametric rigid standard.
Fluorescence molecular endoscopy (FME) is emerging as a “red-flag” technique with potential to deliver earlier, faster, and more personalized detection of disease in the gastrointestinal tract, including cancer, and to gain insights into novel drug distribution, dose finding, and response prediction. However, to date, the performance of FME systems is assessed mainly by endoscopists during a procedure, leading to arbitrary, potentially biased, and heavily subjective assessment. This approach significantly affects the repeatability of the procedures and the interpretation or comparison of the acquired data, representing a major bottleneck towards the clinical translation of the technology. Herein, we propose a robust methodology for FME performance assessment and quality control that is based on a novel multi-parametric rigid standard. This standard enables the characterization of an FME system’s sensitivity through a single acquisition, performance comparison of multiple systems, and, for the first time, quality control of a system as a function of time and number of usages. We show the photostability of the standard experimentally and demonstrate how it can be used to characterize the performance of an FME system. Moreover, we showcase how the standard can be employed for quality control of a system. In this study, we find that the use of composite fluorescence standards before endoscopic procedures can ensure that an FME system meets the performance criteria and that components prone to performance degradation are replaced in time, avoiding disruption of clinical endoscopy logistics. This will help overcome a major barrier for the translation of FME into the clinics.
2024 Scientific Article in Nature metabolism
Non-invasive measurements of blood glucose levels by time-gating mid-infrared optoacoustic signals.
Non-invasive glucose monitoring (NIGM) represents an attractive alternative to finger pricking for blood glucose assessment and management of diabetes. Nevertheless, current NIGM techniques do not measure glucose concentrations in blood but rely on indirect bulk measurement of glucose in interstitial fluid, where glucose is diluted and glucose dynamics are different from those in the blood, which impairs NIGM accuracy. Here we introduce a new biosensor, termed depth-gated mid-infrared optoacoustic sensor (DIROS), which allows, for the first time, non-invasive glucose detection in blood-rich volumes in the skin. DIROS minimizes interference caused by the stratum corneum and other superficial skin layers by time-gating mid-infrared optoacoustic signals to enable depth-selective localization of glucose readings in skin. In measurements on the ears of (female) mice, DIROS displays improved accuracy over bulk-tissue glucose measurements. Our work demonstrates how signal localization can improve NIGM accuracy and positions DIROS as a holistic approach, with high translational potential, that addresses a key limitation of current NIGM methods.
2024 Scientific Article in Journal of Experimental and Clinical Cancer Research
PARP1-targeted fluorescence molecular endoscopy as novel tool for early detection of esophageal dysplasia and adenocarcinoma.
BACKGROUND: Esophageal cancer is one of the 10 most common cancers worldwide and its incidence is dramatically increasing. Despite some improvements, the current surveillance protocol with white light endoscopy and random untargeted biopsies collection (Seattle protocol) fails to diagnose dysplastic and cancerous lesions in up to 50% of patients. Therefore, new endoscopic imaging technologies in combination with tumor-specific molecular probes are needed to improve early detection. Herein, we investigated the use of the fluorescent Poly (ADP-ribose) Polymerase 1 (PARP1)-inhibitor PARPi-FL for early detection of dysplastic lesions in patient-derived organoids and transgenic mouse models, which closely mimic the transformation from non-malignant Barrett's Esophagus (BE) to invasive esophageal adenocarcinoma (EAC). METHODS: We determined PARP1 expression via immunohistochemistry (IHC) in human biospecimens and mouse tissues. We also assessed PARPi-FL uptake in patient- and mouse-derived organoids. Following intravenous injection of 75 nmol PARPi-FL/mouse in L2-IL1B (n = 4) and L2-IL1B/IL8Tg mice (n = 12), we conducted fluorescence molecular endoscopy (FME) and/or imaged whole excised stomachs to assess PARPi-FL accumulation in dysplastic lesions. L2-IL1B/IL8Tg mice (n = 3) and wild-type (WT) mice (n = 2) without PARPi-FL injection served as controls. The imaging results were validated by confocal microscopy and IHC of excised tissues. RESULTS: IHC on patient and murine tissue revealed similar patterns of increasing PARP1 expression in presence of dysplasia and cancer. In human and murine organoids, PARPi-FL localized to PARP1-expressing epithelial cell nuclei after 10 min of incubation. Injection of PARPi-FL in transgenic mouse models of BE resulted in the successful detection of lesions via FME, with a mean target-to-background ratio > 2 independently from the disease stage. The localization of PARPi-FL in the lesions was confirmed by imaging of the excised stomachs and confocal microscopy. Without PARPi-FL injection, identification of lesions via FME in transgenic mice was not possible. CONCLUSION: PARPi-FL imaging is a promising approach for clinically needed improved detection of dysplastic and malignant EAC lesions in patients with BE. Since PARPi-FL is currently evaluated in a phase 2 clinical trial for oral cancer detection after topical application, clinical translation for early detection of dysplasia and EAC in BE patients via FME screening appears feasible.
2024 Scientific Article in Science Advances
Phase-shifting optothermal microscopy enables live-cell mid-infrared hyperspectral imaging of large cell populations at high confluency.
Rapid live-cell hyperspectral imaging at large fields of view (FOVs) and high cell confluency remains challenging for conventional vibrational spectroscopy-based microscopy technologies. At the same time, imaging at high cell confluency and large FOVs is important for proper cell function and statistical significance of measurements, respectively. Here, we introduce phase-shifting mid-infrared optothermal microscopy (PSOM), which interprets molecular-vibrational information as the optical path difference induced by mid-infrared absorption and can take snapshot vibrational images over broad excitation areas at high live-cell confluency. By means of phase-shifting, PSOM suppresses noise to a quarter of current optothermal microscopy modalities to allow capturing live-cell vibrational images at FOVs up to 50 times larger than state of the art. PSOM also reduces illumination power flux density (PFD) down to four orders of magnitude lower than other conventional vibrational microscopy methods, such as coherent anti-Stokes Raman scattering (CARS), thus considerably decreasing the risk of cell photodamage.
