A Renal‐Clearable Macromolecular Reporter for Near‐Infrared Fluorescence Imaging of Bladder Cancer

Bladder cancer (BC) is a prevalent disease with high morbidity and mortality; however, in vivo optical imaging of BC remains challenging because of the lack of cancer‐specific optical agents with high renal clearance. Herein, a macromolecular reporter (CyP1) was synthesized for real‐time near‐infrared fluorescence (NIRF) imaging and urinalysis of BC in living mice. Because of the high renal clearance (ca. 94 % of the injection dosage at 24 h post‐injection) and its cancer biomarker (APN=aminopeptidase N) specificity, CyP1 can be efficiently transported to the bladder and specially turn on its NIRF signal to report the detection of BC in living mice. Moreover, CyP1 can be used for optical urinalysis, permitting the ex vivo tracking of tumor progression for therapeutic evaluation and easy translation of CyP2 as an in vitro diagnostic assay. This study not only provides new opportunities for non‐invasive diagnosis of BC, but also reveals useful guidelines for the development of molecular reporters for the detection of bladder diseases.     

A Renal‐Clearable Duplex Optical Reporter for Real‐Time Imaging of Contrast‐Induced Acute Kidney Injury

Despite its high morbidity and mortality, contrast‐induced acute kidney injury (CIAKI) remains a diagnostic dilemma because it relies on in vitro detection of insensitive late‐stage blood and urinary biomarkers. We report the synthesis of an activatable duplex reporter (ADR) for real‐time in vivo imaging of CIAKI. ADR is equipped with chemiluminescence and near‐infrared fluorescence (NIRF) signaling channels that can be activated by oxidative stress (superoxide anion, O₂^.?) and lysosomal damage (N‐acetyl‐β‐d ‐glucosaminidase, NAG), respectively. By virtue of its high renal clearance efficiency (80 % injected doses after 24 h injection), ADR detects sequential upregulation of O₂^.? and NAG in the kidneys of living mice prior to a significant decrease in glomerular filtration rate (GFR) and tissue damage in the course of CIAKI. ADR outperforms the typical clinical assays and detects CIAKI at least 8 h (NIRF) and up to 16 h (chemiluminescence) earlier.     

Renal‐clearable Molecular Semiconductor for Second Near‐Infrared Fluorescence Imaging of Kidney Dysfunction

Real‐time imaging of kidney function is important to assess the nephrotoxicity of drugs and monitor the progression of renal diseases; however, it remains challenging because of the lack of optical agents with high renal clearance and high signal‐to‐background ratio (SBR). Herein, a second near‐infrared (NIR‐II) fluorescent molecular semiconductor (CDIR2) is synthesized for real‐time imaging of kidney dysfunction in living mice. CDIR2 not only has a high renal clearance efficiency (≈90 % injection dosage at 24 h post‐injection), but also solely undergoes glomerular filtration into urine without being reabsorbed and secreted in renal tubules. Such a unidirectional renal clearance pathway of CDIR2 permits real‐time monitoring of kidney dysfunction in living mice upon nephrotoxic exposure. Thus, this study not only introduces a molecular renal probe but also provides useful molecular guidelines to increase the renal clearance efficiency of NIR‐II fluorescent agents.     

Tailored Zwitterionic Hemicyanine Reporters for Early Diagnosis and Prognostic Assessment of Acute Renal Failure

Drug-induced renal failure (DIRF) poses a serious medical complication with high mortality risk. However, early diagnosis or prognosis of DIRF remain challenging, as current methods rely on detecting late-stage biomarkers. Herein we present a library of zwitterionic unimolecular hemicyanines (ZCs) available for constructing activatable reporters to detect DIRF since its initial stage. Zwitterionic properties of these probes are achieved through interspersedly integrating alkyl sulfonates and quaternary ammonium cations onto hemicyanine skeleton, which result in record low plasma protein binding (<5 %) and remarkable renal clearance efficiencies (≈96 %). An activatable reporter ZCRR is further developed by masking the optimal candidate ZC6 with a tetrapeptide specifically cleavable by caspase-8, an initiating indicator of apoptosis. In living mice with cisplatin-induced DIRF, systematically administered ZCRR efficiently accumulates in kidneys and responds to elevated caspase-8 for near-infrared fluorescence signals ‘turn-on’, enabling sensitive detection of intrarenal apoptosis 60 h earlier than clinical methods, and precise evaluation of apoptosis remediation effects by different medications on DIRF mice. As it's urinary excretable, ZCRR also allows for remote detection of DIRF and predicting renoprotective efficacy through in vitro optical urinalysis. This study thus presents unimolecular renal clearable scaffolds that are applicable to developing versatile activatable reporters for renal diseases management.     

Protease sensors for bioimaging

Optical imaging of specific molecular targets and pathways in vivo has recently become possible through continued developments in imaging equipment, reconstruction algorithms, and more importantly the availability of imaging reporter molecules. These reporter molecules encompass photoproteins expressed in vivo and exogenously administered probes detectable by fluorescence and/or bioluminescence imaging. One particularly enticing aspect of optical imaging is the ability to design activatible probes with inherent amplification. This review summarizes our experience in developing novel near-infrared fluorescent (NIRF) imaging agents that report on protease activities. These agents are designed to be biocompatible, highly activatible, and able to produce bright NIRF following protease cleavage.     

Macrotheranostic Probe with Disease‐Activated Near‐Infrared Fluorescence,Photoacoustic, and Photothermal Signals for Imaging‐Guided Therapy

Theranostics provides opportunities for precision cancer therapy. However, theranostic probes that simultaneously turn on their diagnostic signal and pharmacological action only in respond to a targeted biomarker have been less exploited. We herein report the synthesis of a macrotheranostic probe that specifically activates its near‐infrared fluorescence (NIRF), photoacoustic (PA), and photothermal signals in the presence of a cancer‐overexpressed enzyme for imaging‐guided cancer therapy. Superior to the small‐molecule counterpart probe, the macrotheranostic probe has ideal biodistribution and renal clearance, permitting passive targeting of tumors, in situ activation of multimodal signals, and effective photothermal ablation. Our study thus provides a macromolecular approach towards activatable multimodal phototheranostics.     

Macrotheranostic Probe with Disease‐Activated Near‐Infrared Fluorescence,Photoacoustic, and Photothermal Signals for Imaging‐Guided Therapy

Theranostics provides opportunities for precision cancer therapy. However, theranostic probes that simultaneously turn on their diagnostic signal and pharmacological action only in respond to a targeted biomarker have been less exploited. We herein report the synthesis of a macrotheranostic probe that specifically activates its near‐infrared fluorescence (NIRF), photoacoustic (PA), and photothermal signals in the presence of a cancer‐overexpressed enzyme for imaging‐guided cancer therapy. Superior to the small‐molecule counterpart probe, the macrotheranostic probe has ideal biodistribution and renal clearance, permitting passive targeting of tumors, in situ activation of multimodal signals, and effective photothermal ablation. Our study thus provides a macromolecular approach towards activatable multimodal phototheranostics.     

Folate-targeted co-delivery polymersomes for efficient photo-chemo-antiangiogenic therapy against breast cancer and in vivo evaluation via OCTA/NIRF dual-modal imaging

Intelligent nanoplatform that combines multimodal imaging and therapeutic effects holds great promise for precise and efficient cancer therapy. Herein, folate-targeted polymersomes with stimuli-responsiveness were fabricated and evaluated by near-infrared fluorescence (NIRF) and optical coherence tomography angiography (OCTA) dual-imaging for photo-chemo-antiangiogenic therapy against cancer. The folate-targeted polymersomes (FA-MIT-SIPS) not only integrated ammonium bicarbonate (ABC) and mitoxantrone (MIT) into their hydrophilic cavity but also encapsulated indocyanine green (ICG) and sorafenib (SOR) within their hydrophobic layer. NIRF imaging demonstrated that FA-MIT-SIPS effectively accumulated and retained in the tumors. Upon 808 nm laser irradiation, the ICG produced hyperthermia and reactive oxygen species (ROS) for efficient photothermal and photodynamic therapy. In addition, the decomposition of ABC in responsive to acidic tumor environment and ICG-induced hyperthermia accelerated drug release. The released MIT accumulated in nucleus to inhibit DNA synthesis, while the released SOR destructed tumor vascularization. Notably, OCTA imaging was applied to observe the tumor blood flow upon the combination therapy, demonstrating that FA-MIT-SIPS obviously decreased the vessels area density. Moreover, the synergistic photo-chemo-antiangiogenic therapy of FA-MIT-SIPS achieved excellent antitumor effect with 40% of the 4T1 tumor-bearing mice being completely cured without recurrence. The multifunctional polymersomes provide a promising dual-modal imaging-evaluated synergistic strategy for tumor therapy.     

Size-Transformable Superoxide-Triggered Nanoreporters for Crosstalk-Free Dual Fluorescence/Chemiluminescence Imaging and Urinalysis in Living Mice

Chemiluminescence imaging has been recognized as a valuable tool for ultrasensitive detection of physio-pathological events through elimination of background autofluorescence. However, most chemiluminescent nanoprobes suffer from shallow imaging depths and slow clearance from living bodies, which impede their use in clinical settings. We herein report size-transformable nanoreporters (ADN1 and ADN2) that could be activated at disease site by superoxide anion (O₂⋅⁻) to trigger nanostructure disassembly into renal excretable fluorescent fragments as well as chemiluminescence turn-on for crosstalk-free duplex chemo-fluorescence imaging and in vitro urinalysis. In peritonitis mouse model, we demonstrate that the representative nanoreporter ADN1 spontaneously accumulates at the disrupted peritoneum and is cleaved by upregulated O₂⋅⁻ to initiate depolymerization and result in red chemiluminescence at 620 nm, enabling sensitive detection of peritonitis at least 19 h earlier than gold standard histological assays. Additionally, the incorporation of a near-infrared (NIR) dye into ADN1 results in ADN2 exhibiting intense and red-shifted chemiluminescence at ≈800 nm, which permits early detection of deeply seated diseases such as drug-induced hepatotoxicity. This study thus showcases a modular design strategy that is not only applicable to developing versatile chemiluminescent nanoprobes with switchable pharmacokinetics for early disease diagnosis, but also promising for future clinical translations.     

A Tandem-Locked Fluorescent NETosis Reporter for the Prognosis Assessment of Cancer Immunotherapy

NETosis, the peculiar type of neutrophil death, plays important roles in pro-tumorigenic functions and inhibits cancer immunotherapy. Non-invasive real-time imaging is thus imperative for prognosis of cancer immunotherapy yet remains challenging. Herein, we report a T andem-locked N ETosis R eporter 1 (TNR₁) that activates fluorescence signals only in the presence of both neutrophil elastase (NE) and cathepsin G (CTSG) for the specific imaging of NETosis. In the aspect of molecular design, the sequence of biomarker-specific tandem peptide blocks can largely affect the detection specificity towards NETosis. In live cell imaging, the tandem-locked design allows TNR₁ to differentiate NETosis from neutrophil activation, while single-locked reporters fail to do so. The near-infrared signals from activated TNR₁ in tumor from living mice were consistent with the intratumoral NETosis levels from histological results. Moreover, the near-infrared signals from activated TNR₁ negatively correlated with tumor inhibition effect after immunotherapy, thereby providing prognosis for cancer immunotherapy. Thus, our study not only demonstrates the first sensitive optical reporter for noninvasive monitoring of NETosis levels and evaluation of cancer immunotherapeutic efficacy in tumor-bearing living mice, but also proposes a generic approach for tandem-locked probe design.     

In vivo magnetic resonance detection of cancer by using multifunctional magnetic nanocrystals

The unique properties of magnetic nanocrystals provide them with high potential as key probes and vectors in the next generation of biomedical applications. Although superparamagnetic iron oxide nanocrystals have been extensively studied as excellent magnetic resonance imaging (MRI) probes for various cell trafficking, gene expression, and cancer diagnosis, further development of in vivo MRI applications has been very limited. Here, we describe in vivo diagnosis of cancer, utilizing a well-defined magnetic nanocrystal probe system with multiple capabilities, such as small size, strong magnetism, high biocompatibility, and the possession of active functionality for desired receptors. Our magnetic nanocrystals are conjugated to a cancer-targeting antibody, Herceptin, and subsequent utilization of these conjugates as MRI probes has been successfully demonstrated for the monitoring of in vivo selective targeting events of human cancer cells implanted in live mice. Further conjugation of these nanocrystal probes with fluorescent dye-labeled antibodies enables both in vitro and ex vivo optical detection of cancer as well as in vivo MRI, which are potentially applicable for an advanced multimodal detection system. Our study finds that high performance in vivo MR diagnosis of cancer is achievable by utilizing improved and multifunctional material properties of iron oxide nanocrystal probes.     

Synthesis of NAC capped near infrared-emitting CdTeS alloyed quantum dots and application for in vivo early tumor imaging

The synthesis of water-soluble near-infrared (NIR)-emitting quantum dots (QDs) has recently received extensive attention for non-invasive detection of biological information in living subjects. Highly fluorescent CdTeS alloyed QDs for biological application are introduced in this paper. QDs were synthesized by a hydrothermal method and coated with N-acetyl-l-cysteine (NAC) as both bioactive ligand and sulfur source for biocompatibility and biological stability. The optical properties, morphology and structure of CdTeS alloyed QDs were characterized. The in vitro and in vivo toxicity was intensively investigated. Furthermore, the dynamics and bio-distribution of CdTeS alloyed QDs on living mice were studied. To explore biomedical application, folate-polyethylene glycol (FA-PEG) was used to decorate the CdTeS alloyed QDs (FP-CdTeS QDs) for targeted imaging of tumors over-expressing the folate receptor (FR). The tumor targeting capability of FP-CdTeS QDs on tumor bearing nude mice was demonstrated. The results showed that the prepared CdTeS QDs have excellent optical properties and low toxicity, which makes them an ideal inorganic material for biomedical imaging. In addition, the folate-PEG conjugated NIR-QDs displayed good biocompatibility as well as excellent sensitivity and specificity for optical imaging of tumors which can extend the application of CdTeS QDs.     

Near-infrared fluorescence probes for surgical navigation

Optical imaging is a promising tool for visualizing fundamental biological processes including disease progression, detection of tumors, and therapeutic monitoring non-invasively. Unlike visible light, near-infrared fluorescence (NIRF) imaging (beyond 700–1,700 nm) offers a competitive advantage to yield high-resolution images within a certain penetration depth (few millimeters to centimeters depending on NIR window). The last few years have witnessed rapid development of new NIRF probes within the span of whole NIR window, including small-molecule dyes, inorganic nanoparticles, and organic macromolecules. Benefitted by this, we observe a continual surge in the number of preclinical and clinical studies of NIRF imaging in surgery and related applications. At present, NIRF-guided imaging has emerged as a quintessential procedure to assist surgeons for intraoperative delineation and resection of tumors. Moreover, NIRF imaging is also used to improve the intraoperative staging, identify the hidden lesion in diseased organs, map lymph node metastases, detect tumor margins, and highlight vital organs intraoperatively. Considering rapid advancement of this field, we review recent progress in the development of NIRF probes, cancer-targeting strategies and their application for surgical navigation, particularly for the sentinel lymph node mapping, detection of tumors, and angiography. Moreover, we spotlight surgical navigation instrumentation that is currently used for intraoperative tumor detection.     

Strained Cyclooctyne as a Molecular Platform for Construction of Multimodal Imaging Probes

Small‐molecule‐based multimodal and multifunctional imaging probes play prominent roles in biomedical research and have high clinical translation ability. A novel multimodal imaging platform using base‐catalyzed double addition of thiols to a strained internal alkyne such as bicyclo[6.1.0]nonyne has been established in this study, thus allowing highly selective assembly of various functional units in a protecting‐group‐free manner. Using this molecular platform, novel dual‐modality (PET and NIRF) uPAR‐targeted imaging probe: ⁶⁴Cu‐CHS1 was prepared and evaluated in U87MG cells and tumor‐bearing mice models. The excellent PET/NIRF imaging characteristics such as good tumor uptake (3.69 %ID/g at 2 h post‐injection), high tumor contrast, and specificity were achieved in the small‐animal models. These attractive imaging properties make ⁶⁴Cu‐CHS1 a promising probe for clinical use.     

Controlling electron trap depth to enhance optical properties of persistent luminescence nanoparticles for in vivo imaging

Focusing on the use of nanophosphors for in vivo imaging and diagnosis applications, we used thermally stimulated luminescence (TSL) measurements to study the influence of trivalent lanthanide Ln(3+) (Ln = Dy, Pr, Ce, Nd) electron traps on the optical properties of Mn(2+)-doped diopside-based persistent luminescence nanoparticles. This work reveals that Pr(3+) is the most suitable Ln(3+) electron trap in the diopside lattice, providing optimal trap depth for room temperature afterglow and resulting in the most intense luminescence decay curve after X-ray irradiation. This luminescence dependency toward the electron trap is maintained through additional doping with Eu(2+), allowing UV-light excitation, critical for bioimaging applications in living animals. We finally identify a novel composition (CaMgSi(2)O(6):Eu(2+),Mn(2+),Pr(3+)) for in vivo imaging, displaying a strong near-infrared afterglow centered on 685 nm, and present evidence that intravenous injection of such persistent luminescence nanoparticles in mice allows not only improved but highly sensitive detection through living tissues.     

Dose Dependencies and Biocompatibility of Renal Clearable Gold Nanoparticles: From Mice to Non‐human Primates

While dose dependencies in pharmacokinetics and clearance are often observed in clinically used small molecules, very few studies have been dedicated to the understandings of potential dose‐dependent in vivo transport of nanomedicines. Here we report that the pharmacokinetics and clearance of renal clearable gold nanoparticles (GS‐AuNPs) are strongly dose‐dependent once injection doses are above 15 mg kg^?1: high dose expedited the renal excretion and shortened the blood retention. As a result, the no‐observed‐adverse‐effect‐level (NOAEL) of GS‐AuNPs was >1000 mg kg^?1 in CD‐1 mice. The efficient renal clearance and high compatibility can be translated to the non‐human primates: no adverse effects were observed within 90 days after intravenous injection of 250 mg kg^?1 GS‐AuNPs. These fundamental understandings of dose effect on the in vivo transport of ultrasmall AuNPs open up a pathway to maximize their biomedical potentials and minimize their toxicity in the future clinical translation.     

Thermally cross-linked superparamagnetic iron oxide nanoparticles: synthesis and application as a dual imaging probe for cancer in vivo

We report the fabrication and characterization of thermally cross-linked superparamagnetic iron oxide nanoparticles (TCL-SPION) and their application to the dual imaging of cancer in vivo. Unlike dextran-coated cross-linked iron oxide nanoparticles, which are prepared by a chemical cross-linking method, TCL-SPION are prepared by a simple, thermal cross-linking method using a Si-OH-containing copolymer. The copolymer, poly(3-(trimethoxysilyl)propyl methacrylate-r-PEG methyl ether methacrylate-r-N-acryloxysuccinimide), was synthesized by radical polymerization and used as a coating material for as-synthesized magnetite (Fe3O4) SPION. The polymer-coated SPION was further heated at 80 degrees C to induce cross-linking between the -Si(OH)3 groups in the polymer chains, which finally generated TCL-SPION bearing a carboxyl group as a surface functional group. The particle size, surface charge, presence of polymer-coating layers, and the extent of thermal cross-linking were characterized and confirmed by various measurements, including dynamic light scattering, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The carboxyl TCL-SPION was converted to amine-modified TCL-SPION and then finally to Cy5.5 dye-conjugated TCL-SPION for use in dual (magnetic resonance/optical) in vivo cancer imaging. When the Cy5.5 TCL-SPION was administered to Lewis lung carcinoma tumor allograft mice by intravenous injection, the tumor was unambiguously detected in T2-weighted magnetic resonance images as a 68% signal drop as well as in optical fluorescence images within 4 h, indicating a high level of accumulation of the nanomagnets within the tumor site. In addition, ex vivo fluorescence images of the harvested tumor and other major organs further confirmed the highest accumulation of the Cy5.5 TCL-SPION within the tumor. It is noteworthy that, despite the fact that TCL-SPION does not bear any targeting ligands on its surface, it was highly effective for tumor detection in vivo by dual imaging.     

Metabolic Evaluation of Urine from Patients Diagnosed with High Grade (HG) Bladder Cancer by SPME-LC-MS Method

Bladder cancer (BC) is a common malignancy of the urinary system and a leading cause of death worldwide. In this work, untargeted metabolomic profiling of biological fluids is presented as a non-invasive tool for bladder cancer biomarker discovery as a first step towards developing superior methods for detection, treatment, and prevention well as to further our current understanding of this disease. In this study, urine samples from 24 healthy volunteers and 24 BC patients were subjected to metabolomic profiling using high throughput solid-phase microextraction (SPME) in thin-film format and reversed-phase high-performance liquid chromatography coupled with a Q Exactive Focus Orbitrap mass spectrometer. The chemometric analysis enabled the selection of metabolites contributing to the observed separation of BC patients from the control group. Relevant differences were demonstrated for phenylalanine metabolism compounds, i.e., benzoic acid, hippuric acid, and 4-hydroxycinnamic acid. Furthermore, compounds involved in the metabolism of histidine, beta-alanine, and glycerophospholipids were also identified. Thin-film SPME can be efficiently used as an alternative approach to other traditional urine sample preparation methods, demonstrating the SPME technique as a simple and efficient tool for urinary metabolomics research. Moreover, this study’s results may support a better understanding of bladder cancer development and progression mechanisms.     

Strategies for in vivo imaging of enzyme activity: an overview and recent advances

Imaging of enzyme activity in living subjects promises many applications in both basic and translational researches from helping elucidate the enzyme function and mechanism in biology to better disease detection and monitoring, but the complexity and dynamics of enzymatic reactions in living systems present unique challenges for probe design. This critical review examines the approaches in recent literature to in vivo imaging of the activity of a variety of enzyme targets with an emphasis on the chemical perspective of probe design, structure and function. Strategies for designing enzyme-activated probes based on a variety of molecular scaffolds including small molecules, organic and inorganic nanoparticles, and genetically encoded proteins for commonly used molecular imaging modalities--whole body optical (fluorescence, bioluminescence) imaging, magnetic resonance imaging, and radionuclide-based tomographic imaging, are critically evaluated. Recent advances in combining multiple modalities to imaging enzyme activity in living subjects are also highlighted (255 references).     

亲水作用色谱/质谱联用方法用于膀胱癌患者血清代谢组学研究

膀胱癌是泌尿系统最常见的恶性肿瘤之一,具有高发病率、高复发率和高进展率的特点.本研究应用69个极性代谢物标样选择合适的分离系统,建立了两性离子亲水作用色谱/质谱联用的代谢组学分析方法.本方法线性范围较宽,检出限低于ng/mL数量级.将本方法用于血清代谢组学分析,85%以上代谢物峰面积的RSD<30%.对64例膀胱癌患者和32例正常人的血清进行代谢组学研究,发现溶血磷脂酰胆碱、游离脂肪酸、氨基酸、胆汁酸、有机酸、核苷等在患病组和正常组中存在显著差异.经筛选和验证,甘磷酸胆碱、胱氨酸、十二碳烯酸、二十碳烯酸和鹅去氧胆酸5种代谢物可以作为区分膀胱癌和正常人的潜在标志物.本研究结果表明,基于亲水作用色谱/质谱联用的代谢组学方法是发现癌症诊断潜在生物标志物的有效手段.