Near-infrared Fluorescence Signal Research Articles

Design of a New Hydrazine Moiety-Based Near-Infrared Fluorescence Probe for Detection and Imaging of Endogenous Formaldehyde In Vivo.

Formaldehyde (FA), the smallest molecular aldehyde with strong reducing properties, could regulate body homeostasis endogenously during physiological and pathological processes. The effective near-infrared (NIR) fluorescent probe is needed as a visualizer of FA in biologic organisms. In this work, a novel NIR fluorescent Probe-NHNH2 was designed on the basis of Probe-NH2 via introducing a strong nucleophilic hydrazine group, which can be used as a quenching and recognizing moiety for the detection of FA. With the treatment of FA, the hydrazine group of Probe-NHNH2 undergoes condensation and achieves a turn-on NIR fluorescence signal at a wavelength of 706 nm. The spectroscopic performance of Probe-NHNH2 for FA was evaluated, and it exhibited high sensitivity and selectivity for the detection of FA in solution. Moreover, compared to the amine moiety-based Probe-NH2, which our group reported, we found that hydrazine moiety-based Probe-NHNH2, exhibited a better reaction time of within 10 min and a lower detection limit of 0.68 μM, reflecting that the reaction of FA with hydrazine moiety is faster and more sensitive than that of FA with the amino group. More importantly, Probe-NHNH2 was successfully applied to real-time imaging of endogenous FA by reacting with effective stimulant tetrahydrofolate and scavenger sodium bisulfite in zebrafish and mice. It is expected that we can provide a new rapid, sensitive NIR fluorescence theoretical basis for FA detection and in vivo imaging applications.

Construction of mitochondria targeted and FRET based ratiometric sensing nanoplatform for sulfur dioxide accurate detection in vitro and in vivo

Sulfur dioxide (SO2) is a key molecule in organisms that is involved in the regulation of different physiological procedures. Aberrant SO2 causes a variety of diseases, such as cancer and neurodegeneration. Thus, sensitive and selective detection of SO2 is of great importance. Based on the Förster resonance energy transfer (FRET) between green fluorescence carbon dots (GCDs) donor and amide-linked near-infrared fluorescence emissive organic small molecular dye (CDDBT) acceptor, one ratiometric fluorescent nano platform, Mito-GCDs-CDDBT for mitochondria SO2 sensing was constructed. In this FRET sensing system, CDDBT served as the receptor for SO2, and the presence of SO2 enhanced GCDs green fluorescence signal and quenched CDDBT near-infrared fluorescence signal due to the disruption of FRET. Mito-GCDs-CDDBT could sensitively detect SO2 with a detection limit of as low as 0.701 μM. Meanwhile, Mito-GCDs-CDDBT achieved fluorescence imaging to measure the response of cellular exogenous and endogenous SO2 with remarkable mitochondrial targeting. Moreover, Mito-GCDs-CDDBT also realized SO2 sensing in vivo including zebrafish and mice. The as-prepared versatile nanoplatform displayed several advantages, such as mitochondria targeting, FRET-based sensitive detection, and sensing capabilities in biological milieu. Potentially, it could be applied in the diagnostics of SO2 involved diseases.

Preclinical evaluation of a novel cathepsin-activated fluorescent probe VGT-309 for identification of ovarian cancer in a mouse model (248)

<b>Objectives:</b> Cathepsin activity is upregulated in many solid cancers. VGT-309 is a novel near-infrared cathepsin-activated fluorescent probe that covalently binds to cysteine cathepsins, localizing the fluorescent signal to sites of high cathepsin activity. The goal was to determine the utility of VGT-309 in a mouse model of ovarian cancer. <b>Methods:</b> NCG mice with luciferase-labeled ovarian cancer cell lines (OVCAR3-ffLuc, OVCAR8-ffLuc), implanted subcutaneously (SQ) (<i>n</i>=6) or intraperitoneally (IP) (<i>n</i>=6), were injected with intravenous VGT-309 (2 mg/kg) and sacrificed after 24 hours for fluorescence imaging and anatomical dissection. Near-infrared (NIR) and luciferase imaging were performed on tumors and internal organs with the Pearl Imaging system. Image Studio Lite was used to quantitate fluorescence signals. Background muscle signal was compared with specimen signal from various sized tumors and organs to establish signal-to-background ratio (SBR) and an average was taken. <b>Results:</b> Twenty-four hours after mice were injected with VGT-309, we were able to visualize NIR fluorescence signal in SQ mouse models for OVCAR3 and OVCAR8 <i>in situ</i>. After dissecting tumors and organs, we compared NIR fluorescence activity with luciferase activity. The fluorescence signal from VGT-309 overlapped with the luciferase signal, indicating that VGT-309 was able to specifically image cancerous tissue in both SQ and IP models. There was high SBR noted for the tumors from the SQ tumor models (SBR 14 for OVCAR8 and 14.3 for OVCAR3), as compared to the peritoneum (SBR 0.7 for OVCAR8 and 0.6 for OVCAR3). Similar findings were also noted for the IP tumors (SBR 10.1 for OVCAR8 and 12.6 for OVCAR3) as compared to the peritoneum (SBR 1.4 for OVCAR8 and 0.6 for OVCAR3). <b>Conclusions:</b> VGT-309 is a cathepsin-based activatable fluorescence probe that can visualize ovarian cancer cells in an animal model with a high signal-to-background ratio as compared to the peritoneum. VGT-309 is currently in early phase clinical trials for lung cancer. These data would encourage clinical testing of VGT-309 as a tool for the intraoperative identification of ovarian cancers.

Hypoxia-responsive near infrared thioxanthene-hemicyanine nanoparticle for multimodal imaging-guided photothermal/photodynamic therapy

Multimodal imaging-guided phototherapy is an emerging treatment for tumor elimination that can provide more physiological and pathological information for precise theranostics with minimal side effects. Herein, we proposed a novel hypoxia-activated near infrared (NIR) probe (AzoCyS-N) based on a thioxanthene-hemicyanine scaffold for tumor multimodal imaging and photothermal/photodynamic therapy. The thioxanthene-hemicyanine fluorophore (CyS-NH2) could be released from AzoCyS-N via reductive cleavage of the azo group under hypoxia, resulting in a dramatically enhanced NIR fluorescence signal at 760 nm and redshifted absorption at 730 nm. AzoCyS-N was further encapsulated into a folic acid modified amphiphilic polymer to form AzoCyS-N NPs to further improve the tumor selectivity. In addition, the released Cys-NH2 could generate singlet oxygen and exhibited decent photothermal effects under 690 nm light irradiation. The in vivo studies confirmed that the NIR fluorescence and PA signals in the tumor region were selectively lightened after intravenous injection of AzoCyS-N NPs. Finally, solid tumor growth was significantly suppressed by the synergistic effect of PDT and PTT. This work provides a powerful multimode imaging-guided synergistic phototherapeutic system for precise tumor theranostics.

Near-infrared probe for early diagnosis of diabetic complications-nephropathy and in vivo visualization fluorescence imaging research

Diabetic nephropathy is one of the common complications of diabetes, which has high risk of renal function. Dipeptidyl peptidase 4 (DPP4) is considered to be one of the good dynamic monitoring indicators for early diabetic nephropathy. Therefore, real-time monitoring of changes in the activity of DPP4 in organisms is helpful to the diagnosis and treatment of diabetes and its complications-diabetic nephropathy. A near-infrared fluorescent probe GP-DCMNH2 is designed to detect the activity of DPP4. GP-DCMNH2 is catalyzed and hydrolyzed by DPP4 into the near-infrared fluorescent dye DCMNH2, to achieve the purpose of detecting DPP4 in organisms. Based on the excellent near-infrared spectroscopy characteristics displayed by the probe GP-DCMNH2 in vitro, in living cells and diabetic mouse models, GP-DCMNH2 has been further applied in the visual fluorescence imaging of diabetic complications-diabetic nephropathy. Compared with the control group and the treatment group, GP-DCMNH2 showed a stronger near-infrared fluorescence signal in the kidney tissue and blood of diabetic nephropathy mice. Because GP-DCMNH2 shows high sensitivity in real-time dynamic monitoring of changes in the activity of DPP4 in organisms, and shows strong practicability in the spectral test of mouse models of diabetes and diabetic nephropathy. In clinical medicine, GP-DCMNH2 is expected to be used in the early diagnosis, prevention and treatment of diabetes and diabetic nephropathy.

Optimization of Multimodal Nanoparticles Internalization Process in Mesenchymal Stem Cells for Cell Therapy Studies.

Considering there are several difficulties and limitations in labeling stem cells using multifunctional nanoparticles (MFNP), the purpose of this study was to determine the optimal conditions for labeling human bone marrow mesenchymal stem cells (hBM-MSC), aiming to monitor these cells in vivo. Thus, this study provides information on hBM-MSC direct labeling using multimodal nanoparticles in terms of concentration, magnetic field, and period of incubation while maintaining these cells’ viability and the homing ability for in vivo experiments. The cell labeling process was assessed using 10, 30, and 50 µg Fe/mL of MFNP, with periods of incubation ranging from 4 to 24 h, with or without a magnetic field, using optical microscopy, near-infrared fluorescence (NIRF), and inductively coupled plasma mass spectrometry (ICP-MS). After the determination of optimal labeling conditions, these cells were applied in vivo 24 h after stroke induction, intending to evaluate cell homing and improve NIRF signal detection. In the presence of a magnetic field and utilizing the maximal concentration of MFNP during cell labeling, the iron load assessed by NIRF and ICP-MS was four times higher than what was achieved before. In addition, considering cell viability higher than 98%, the recommended incubation time was 9 h, which corresponded to a 25.4 pg Fe/cell iron load (86% of the iron load internalized in 24 h). The optimization of cellular labeling for application in the in vivo study promoted an increase in the NIRF signal by 215% at 1 h and 201% at 7 h due to the use of a magnetized field during the cellular labeling process. In the case of BLI, the signal does not depend on cell labeling showing no significant differences between unlabeled or labeled cells (with or without a magnetic field). Therefore, the in vitro cellular optimized labeling process using magnetic fields resulted in a shorter period of incubation with efficient iron load internalization using higher MFNP concentration (50 μgFe/mL), leading to significant improvement in cell detection by NIRF technique without compromising cellular viability in the stroke model.

Activatable Fluorescent-Photoacoustic Integrated Probes with Deep Tissue Penetration for Pathological Diagnosis and Therapeutic Evaluation of Acute Inflammation in Mice.

Inflammation is associated with many diseases, so the development of an excellent near infrared fluorescent (NIRF) and photoacoustic (PA) dual-modality probe is crucial for the accurate diagnosis and efficacy evaluation of inflammation. However, most of the current NIRF/PA scaffolds are based on repurposing existing fluorescent dye platforms that exhibit non-optimal properties for both NIRF and PA signal outputs. Herein, we developed a novel dye scaffold QL-OH by optimizing the NIRF and PA signal of classical hemicyanine dyes. Based on this optimized dye, we developed the first NIRF/PA dual-mode carbon monoxide (CO) probe QL-CO for noninvasive and sensitive visualization of CO levels in deep inflammatory lesions in vivo. The novel probe QL-CO exhibited rapid and sensitive NIRF775/PA730 dual activation responses toward CO. In addition, the CO-activated probe QL-CO was successfully used for the diagnosis of inflammation and evaluation of anti-inflammation drug efficacy in living mice though the NIRF/PA dual-mode imaging technology for the first time. More importantly, the probe QL-CO could accurately locate the deep inflammatory lesion tissues (≈1 cm) in mice and obtain 3D PA diagnostic images with deep penetration depth and spatial resolution. Therefore, the new NIRF/PA dual-mode probe QL-CO has high potential for deep-tissue diagnosis imaging of CO in vivo. These findings may provide a new tool and approach for future research and diagnosis of CO-associated diseases.

Vehicle-Free Nanotheranostic Self-Assembled from Clinically Approved Dyes for Cancer Fluorescence Imaging and Photothermal/Photodynamic Combinational Therapy.

Phototherapy, including photothermal therapy (PTT) and photodynamic therapy (PDT) has attracted growing attention as a noninvasive option for cancer treatment. At present, researchers have developed various “all-in-one” nanoplatforms for cancer imaging and PTT/PDT combinational therapy. However, the complex structure, tedious preparation procedures, overuse of extra carriers and severe side effects hinder their biomedical applications. In this work, we reported a nanoplatform (designated as ICG-MB) self-assembly from two different FDA-approved dyes of indocyanine green (ICG) and methylene blue (MB) without any additional excipients for cancer fluorescence imaging and combinational PTT/PDT. ICG-MB was found to exhibit good dispersion in the aqueous phase and improve the photostability and cellular uptake of free ICG and MB, thus exhibiting enhanced photothermal conversion and singlet oxygen (1O2) generation abilities to robustly ablate cancer cells under 808 nm and 670 nm laser irradiation. After intravenous injection, ICG-MB effectively accumulated at tumor sites with a near-infrared (NIR) fluorescence signal, which helped to delineate the targeted area for NIR laser-triggered phototoxicity. As a consequence, ICG-MB displayed a combinational PTT/PDT effect to potently inhibit tumor growth without causing any system toxicities in vivo. In conclusion, this minimalist, effective and biocompatible nanotheranostic would provide a promising candidate for cancer phototherapy based on current available dyes in clinic.

An Activatable Polymeric Nanoprobe for Fluorescence and Photoacoustic Imaging of Tumor-Associated Neutrophils in Cancer Immunotherapy.

Imaging to evaluate tumor-associated neutrophils (TANs) is imperative for cancer immunotherapy but remains challenging. We herein report an activatable semiconducting polymer nanoprobe (SPCy) for near-infrared fluorescence (NIRF) and photoacoustic (PA) imaging of neutrophil elastase (NE), a biomarker of TANs. SPCy comprises a semiconducting polymer conjugated with a hemicyanine (hemi-Cy) dye caged by a NE-cleavable peptide as the side chain. After systemic administration, SPCy passively targets the tumor and reacts with NE to "uncage" the hemi-Cy, leading to enhanced NIRF and PA signals of the hemi-Cy but unchanged signals of the SP. Such NE-activated ratiometric NIRF and enhanced PA signals of SPCy correlate with the intratumoral population of TANs. Thus, this study not only presents the first TAN-specific PA probe, but also provides a general molecular design strategy for PA imaging of other immune-related biomarkers to facilitate screening of cancer immunotherapeutics.

An Activatable Polymeric Nanoprobe for Fluorescence and Photoacoustic Imaging of Tumor‐Associated Neutrophils in Cancer Immunotherapy

AbstractImaging to evaluate tumor‐associated neutrophils (TANs) is imperative for cancer immunotherapy but remains challenging. We herein report an activatable semiconducting polymer nanoprobe (SPCy) for near‐infrared fluorescence (NIRF) and photoacoustic (PA) imaging of neutrophil elastase (NE), a biomarker of TANs. SPCy comprises a semiconducting polymer conjugated with a hemicyanine (hemi‐Cy) dye caged by a NE‐cleavable peptide as the side chain. After systemic administration, SPCy passively targets the tumor and reacts with NE to “uncage” the hemi‐Cy, leading to enhanced NIRF and PA signals of the hemi‐Cy but unchanged signals of the SP. Such NE‐activated ratiometric NIRF and enhanced PA signals of SPCy correlate with the intratumoral population of TANs. Thus, this study not only presents the first TAN‐specific PA probe, but also provides a general molecular design strategy for PA imaging of other immune‐related biomarkers to facilitate screening of cancer immunotherapeutics.

PD53-10 IDENTIFYING BLADDER UROTHELIAL CARCINOMAS USING FLUORESCENT SIGNAL INTENSITY OF PH LOW INSERTING PEPTIDES

You have accessJournal of UrologyCME1 May 2022PD53-10 IDENTIFYING BLADDER UROTHELIAL CARCINOMAS USING FLUORESCENT SIGNAL INTENSITY OF PH LOW INSERTING PEPTIDES Borivoj Golijanin, Michael DuPont, Ali Amin, Anna Moshnikova, Ohad Kott, Yana Reshetnyak, Oleg Andreev, and Dragan Golijanin Borivoj GolijaninBorivoj Golijanin More articles by this author , Michael DuPontMichael DuPont More articles by this author , Ali AminAli Amin More articles by this author , Anna MoshnikovaAnna Moshnikova More articles by this author , Ohad KottOhad Kott More articles by this author , Yana ReshetnyakYana Reshetnyak More articles by this author , Oleg AndreevOleg Andreev More articles by this author , and Dragan GolijaninDragan Golijanin More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002630.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Urothelial carcinomas (UC) are heterogenous malignancy with an acidic microenvironment. pH low insertion peptides (pHLIPs) are a class of pH specific transmembrane peptides that target the acidic microenvironment of cancer cells. pHLIP variant-3 (Var3-pHLIP) was conjugated to a near infrared fluorescent (NIRF) dye to evaluate the specificity and sensitivity as a UC targeting molecular probe. METHODS: After incubation for 15 minutes with Var3-pHLIP conjugated to indocyaninie green (ICG) or IRDye® 800CW, 38 ex-vivo bladder specimens from patients undergoing robotic assisted laparoscopic radical cystectomy for bladder cancer were placed under NIRF capable laser to excite the fluorophore. Peak signal intensity and the corrected mean intensity of malignant and nonmalignant cases were analyzed. The number of lesions visible under NIRF was compared with the number identified under white light. Paired-samples t-test was used to analyzed these data. Expression of NIRF signal and identification of lesions under white light by urologic oncology pathologist were compared to histopathology for specificity and sensitivity calculations. RESULTS: Of 58 lesions processed for histopathology, 47 (81%) were seen under white light and 57 (98.3%) were seen with Var3-pHLIP, representing an improved diagnosis by 17.3% (p=0.003). In NIRF, Var3-pHLIP demonstrated an average peak signal intensity of 116.4 relative fluorescent units (RFU) in malignant cases, and nonmalignant cases demonstrated an average of 44.3 RFU (p <0.001). Corrected average signal intensity of malignant cases demonstrated an average of 52.9 RFU/μm2 and nonmalignant cases demonstrated an average of 25 RFU/μm2 (p <0.001). Var3-pHLIP demonstrated 98% sensitivity and 100% specificity in identification of UC. CONCLUSIONS: NIRF of Var3-pHLIP enhanced visualization and improved diagnosis of UC. Categorizing into the borader categories of malignant and nonmalignant, the unique Var3-pHLIP NIRF signal can be used to differentiate the two groups on both peak signal intensity and mean intensity per unit area of lesion. NIRF of Var3-pHLIP identified UC irrespective of subtype, previous treatment, and stage. All CIS cases missed by white light cystoscopy were diagnosed using Var3-pHLIP NIRF imaging. Additional work into digital, automated analysis of Var3-pHLIP NIRF signal and development of a fluorescent signal analysis capable cystoscope can lead to diagnosis of bladder cancer at the time of cystoscopy. Source of Funding: This study was funded by internal departmental funds allocated to DG, OA, and YK © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e913 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Borivoj Golijanin More articles by this author Michael DuPont More articles by this author Ali Amin More articles by this author Anna Moshnikova More articles by this author Ohad Kott More articles by this author Yana Reshetnyak More articles by this author Oleg Andreev More articles by this author Dragan Golijanin More articles by this author Expand All Advertisement PDF DownloadLoading ...

A Dual-Locked Activatable Phototheranostic Probe for Biomarker-Regulated Photodynamic and Photothermal Cancer Therapy.

Activatable phototheranostics holds promise for precision cancer treatment owing to the "turn-on" signals and therapeutic effects. However, most activatable phototheranostic probes only possess photodynamic therapy (PDT) or photothermal therapy (PTT), which suffer from poor therapeutic efficacy due to deficient cellular oxygen and complex tumor microenvironment. We herein report a dual-locked activatable phototheranostic probe that activates near-infrared fluorescence (NIRF) signals in tumor, triggers PDT in response to a tumor-periphery biomarker, and switches from PDT to PTT upon detecting a tumor-core-hypoxia biomarker. This PDT-PTT auto-regulated probe exhibits complete tumor ablation under the photoirradiation of a single laser source by producing cytotoxic singlet oxygen at the tumor periphery and generating hyperthermia at tumor-core where is too hypoxic for PDT. This dual-locked probe represents a promising molecular design approach toward precise cancer phototheranostics.

Noncovalent Dual-Locked Near-Infrared Fluorescent Probe for Precise Imaging of Tumor via Hypoxia/Glutathione Activation.

Stimulus-responsive fluorescent probes have broad applications in the early detection and treatment of tumors and thus promote the personalized treatment of tumors and improve patient survival. Among the repertoires of probes, dual-locked near-infrared (NIR) fluorescent probes are of great significance due to their improved specificity and multiplex detection in tumor imaging but remain to be explored. In this work, a facile noncovalent strategy for constructing dual-locked probes was proposed. A glutathione (GSH)-activatable single-locked probe CySS (first lock) was preloaded into a hypoxia-responsive molecular container CF3C4A (second lock) through a host-guest interaction to form the dual-locked probe CF3C4A-CySS. Under physiological conditions, CF3C4A-CySS binds strongly to avoid undesired leakage in normal tissues. We have proven that CF3C4A-CySS can be activated and "turn on" its NIR fluorescent signal under the dual key stimulation of hypoxia and GSH in the tumor microenvironment, which enables precise tumor imaging with enhanced accuracy and specificity. Both in vitro and in vivo results indicated the superiority of CF3C4A-CySS in tumor imaging. This work not only provides an effective tool for tumor imaging but also proposes a promising strategy for dual-locked imaging agent construction.

Quantification of near-infrared fluorescence imaging with indocyanine green in free flap breast reconstruction

One of the complications of free flap breast reconstruction is the occurrence of skin and fat necrosis. Intra-operative use of near-infrared (NIR) fluorescence imaging with Indocyanine Green (ICG) has the potential to predict these complications. In this study, the quantification of the fluorescence intensity measured in free flap breast reconstruction was performed to gain insight into the perfusion patterns observed with ICG NIR fluorescence imaging. ICG NIR fluorescence imaging was performed in patients undergoing free flap breast reconstruction following mastectomy. After completion of the arterial and venous anastomosis, 7.5mg ICG was administered intravenously. The fluorescence intensity over time was recorded using the Quest Spectrum Platform®. Four regions of interest (ROI) were selected based on location and interpretation of the NIR fluorescence signal: (1) The perforator, (2) normal perfusion, (3) questionable perfusion, and (4) low perfusion. Time-intensity curves were analyzed, and two parameters were extracted: Tmax and Tmax slopes. Successful ICG NIR fluorescence imaging was performed in 13 patients undergoing 17 free flap procedures. Region selection included 16 perforators, 17 normal perfusions, 8 questionable perfusions, and 5 low perfusion ROIs. Time-intensity curves of the perforator ROIs were comparable to the ROIs of normal perfusion and demonstrated a fast inflow. No outflow was observed for the ROIs with questionable and low perfusion. This study provides insight into the perfusion patterns observed with ICG NIR fluorescence imaging in free flap breast reconstruction. Future studies should correlate quantitative parameters with clinical perfusion assessment and outcome.

Tumor microenvironment pH-responsive pentagonal gold prism-based nanoplatform for multimodal imaging and combined therapy of castration-resistant prostate cancer

Given that there is lack of effective therapies for castration-resistant prostate cancer (CRPC), the combination of photothermal (PTT), photodynamic (PDT), and chemical therapy (CT) has emerged as a prominent strategy. Tumor-targeted delivery and controlled release of antitumor drug are key-elements of any combined therapy. Considering these important elements, we designed and constructed tumor microenvironment (TME)-activated nanoprobes (PGP/CaCO3@IR820/DTX-HA). The CaCO3 shell could efficiently entrap the photosensitizer IR820 and the chemotherapeutic docetaxel (DTX) on the surface of pentagonal gold prisms (PGPs) to prevent elimination from the circulation, and it could act as a TME-trigger to achieve TME-responsive drug release. After modification with hyaluronic acid, PGP/CaCO3@IR820/DTX-HA was capable of synergistic TME-triggered PTT/PDT/CT and tumor-targeted delivery. Our in vitro and in vivo studies demonstrate that PGP/CaCO3@IR820/DTX-HA could achieve synergistic antitumor effects following near-infrared (NIR)-light irradiation. In addition, using the NIR fluorescence signal from IR820 and the photoacoustic (PA) signal from PGPs, i.e., through multimodal fluorescence/photoacoustic imaging, we could monitor the in vivo distribution and excretion of PGP/CaCO3@IR820/DTX-HA. Therefore, it can be concluded that PGP/CaCO3@IR820/DTX-HA shows promising clinical translational potential as a treatment for CRPC. Statement of significanceUtilizing pentagonal gold prisms (PGPs), we constructed a multifunctional nanoplatform (PGP/CaCO3@IR820/DTX-HA) for effectively delivering agents into the tumor microenvironment (TME) for the diagnosis and therapy of castration-resistant prostate cancer (CRPC). The synthetic nanoplatform can satisfy TME-activated synergistic photothermal therapy (PTT)/photodynamic therapy (PDT)/chemical therapy (CT) and NIR fluorescence imaging/photoacoustic (PA) imaging. Hyaluronic acid (HA) on the surface of nanoplatform allowed the specific tumor-targeting capacity and biocompatibility. In conclusion, PGP/CaCO3@IR820/DTX-HA could be a promising integrated nanoplatform for CRPC diagnosis and treatment.

Near-Infrared Mitochondria-Targetable Single-Molecule probe for Dual-Response of viscosity and sulfur dioxide in vivo

Studies have demonstrated that the viscosity and SO2 in mitochondria are involved in various physiological processes, which are both important for maintaining the normal function of mitochondria. In this research, we rationally designed and synthesized a novel mitochondria-targetable fluorescent probe Mito-MG with near-infrared absorption and emission for dual-response of viscosity and SO2. Based on the TICT mechanism and Michael addition reaction, the probe Mito-MG responds to viscosity and SO2 with different near-infrared fluorescence signals. Importantly, Mito-MG presented outstanding mitochondrial targeting ability (Pearson’s colocalization coefficient is 0.8602) and has been successfully applied to imaging of the cells, zebrafish and mice. We believe that Mito-MG could be applied as a powerful tool for a deep understanding of the connection of viscosity and SO2 in biological systems.

Abstract 12629: Intravascular Dual Targeted NIRF Molecular Imaging Integrated With OCT for Calcifying Inflammatory Activity in the Plaque

Background/Objectives: Spotty calcification linked with macrophage activity is a major target for high-risk plaque but the biological interconncetion remains questionable. To address this issue, we newly developed intravascular multimodal imaging strategy by fully integration of OCT with dual-targeted near-infrared fluorescence (NIRF) molecular imaging using customized osteogenic activity and macrophage targetable probes. Methods/Results: We newly integrated intravascular OCT structural imaging with dual-targeted NIRF imaging. Scale-up novel NIRF emitting probe targeting osteogenic activity was fabricated by chemically coupling alendronate ligand and Cy5.5 to the ends of azide-PEG-NHS ester (Al-Cy5.5). Based on biodistribution, OCT/dual-NIRF in vivo imaging of rabbit aortoiliac atheroma was acquired 72 hrs after intravenous injection of Al-Cy5.5 (5.0 mg/kg) and macrophage mannose receptor targeted Cy7-emitting probe (7.5 mg/kg). NIRF signals of Cy5.5 and Cy7 were highly enhanced in spotty calcification and inflammatory sites of the plaque, respectively (Figure) (p&lt;0.01). Fluorescence microscopy and immunostainings from the corresponding sections well corroborated the in vivo findings. Intriguingly, an interconnection of osteogenic activity (TRAP stain) with macrophages was more prominent in superficial spotty calcification rather than outer dense calcification (Figure) (p&lt;0.01). Conclusions: Our intravascular OCT/dual-NIRF imaging was feasible to simultaneously image osteogenic activity and macrophages in the coronary-sized atheroma. This novel imaging strategy is expected to expand the understanding for the biological behavior of calcifying inflamed activity in the high-risk plaques existing on cap microcalcification.

Renal-Clearable Molecular Probe for Near-Infrared Fluorescence Imaging and Urinalysis of SARS-CoV-2.

Despite the importance of rapid and accurate detection of SARS-CoV-2 in controlling the COVID-19 pandemic, current diagnostic methods are static and unable to distinguish between viable/nonviable virus or directly reflect viral replication activity. Real-time imaging of protease activity specific to SARS-CoV-2 can overcome these issues but remains lacking. Herein, we report a near-infrared fluorescence (NIRF) activatable molecular probe (SARS-CyCD) for detection of SARS-CoV-2 protease in living mice. The probe comprises a hemicyanine fluorophore caged with a protease peptide substrate and a cyclodextrin unit, which function as an NIRF signaling moiety and a renal-clearable enabler, respectively. The peptide substrate of SARS-CyCD can be specifically cleaved by SARS-CoV-2 main protease (Mpro), resulting in NIRF signal activation and liberation of the renal-clearable fluorescent fragment (CyCD). Such a design not only allows sensitive detection of Mpro in the lungs of living mice after intratracheal administration but also permits optical urinalysis of SARS-CoV-2 infection. Thus, this study presents an in vivo sensor that holds potential in preclinical high-throughput drug screening and clinical diagnostics for respiratory viral infections.

Er3+-Ions-Doped Multiscale Nanoprobes for Fluorescence Imaging in Cellular and Living Mice.

With the development of biotechnology, luminescent nanoprobes for biological disease detection are widely used. However, the further application in clinic is limited by the reduced penetration depth in the tissues and light scattering. In this work, we have synthesized NaYF4:Yb,Er,Ce@SiO2-OAlg nanomaterials, which have both upconversion and near-infrared (NIR) luminescence. The optimized probes were determined to achieve cell imaging by its upconversion (UCL) luminescence and in vivo imaging through collection of NIR fluorescence signals simultaneously. The research is conducive to developing accurate diagnostic techniques based on UCL and NIR fluorescence imaging by a single nanoparticle.

Sensing and imaging of exosomal CD26 secreted from cancer cells and 3D colorectal tumor model using a novel near-infrared fluorogenic probe

Cancer-derived exosomes or their specific components hold great promise for early diagnosis and precise staging of cancers. This work aimed to construct a novel enzyme-activatable fluorescent substrate for real-time detection and in situ imaging of a key exosomal surface protein CD26 in various biological systems, as well as to reveal the relevance of exosomal CD26 to the tumorigenesis. For these purposes, a group of Gly-Pro amides deriving from several near-infrared fluorophores were designed on the basis of the unique prolyl-cleaving dipeptidease activity of CD26, while molecular docking simulations were applied to assess the possibility of the designed amides as CD26 specific substrates. Following virtual screening and experimental validation, it was observed that GP-ACM displayed the best combination of high sensitivity and excellent specificity to CD26. The sensing and imaging ability of GP-ACM towards CD26 were examined in a range of biological systems, such as living cells, in situ tissues, and the exosomes secreted from cancer cells. Under physiological conditions, GP-ACM can be readily hydrolyzed by CD26 to release the fluorescent product ACM. The fluorescent product emits strong near-infrared fluorescence signals around 660 nm, which can be easily captured by the devices equipped with a fluorescence detector. GP-ACM prolyl-cleaving reaction shows excellent specificity and rapid response towards CD26, while its fluorescent product ACM displays good chemical stability and outstanding photostability. With the help of GP-ACM, CD26 in living cells, tissues and the tumor-secreted exosomes can be real-time monitored and in-situ imaged, while further investigations reveal that the exosomal CD26 activities are abnormally elevated with the progression of colon tumor. Collectively, the present study offers a practical optical assay for real-time monitoring CD26 activities in multiple complex biological systems including the exosomes secreted by tumor cells. The simplicity and effectiveness of this assay hold great potential for facilitating fundamental researches and clinical diagnosis of exosomal CD26 associated diseases.