Near-infrared fluorescence imaging in immunotherapy

Infrared radiation for cancer hyperthermia: the light to brighten up oncology

INTRODUCTION

Cancer constitutes the greatest public health threat to humans, as its incidence and mortality rates continue to increase worldwide. With the development of medical physics, more practitioners focus on the direct and indirect anti-tumor effects of physical factors. Infrared radiation (INR) is currently the most rapidly developing physical therapy method for tumors and has become a favored target for many oncologists and researchers owing to its advantages of high efficiency, low toxicity, and strong feasibility.

AREAS COVERED

This work provides a comprehensive collection of the latest information on INR anti-tumor research, drawing from public medical databases (PubMed, Web of Science, Embase, and Clinical Trials) from the last 10 years (2014 to 2024), and encompassing both basic and clinical research in oncology and physics. This article reviews the application of INR in tumor hyperthermia, summarizes and analyzes the practical value of INR for tumor treatment, and discusses future development trends to provide valuable assistance for the subsequent development of oncology.

EXPERT OPINION

Currently, INR has continuously accumulated excellent data in the field of tumor hyperthermia, bringing practical survival benefits to patients with cancer, and playing an important role in basic and clinical cancer research.

Bifunctional mesoporous HMUiO-66-NH2 nanoparticles for bone remodeling and ROS scavenging in periodontitis therapy

Periodontal bone defects represent an irreversible consequence of periodontitis associated with reactive oxygen species (ROS). However, indiscriminate removal of ROS proves to be counterproductive for tissue repair and insufficient for addressing existing bone defects. In the treatment of periodontitis, it is crucial to rationally alleviate local ROS while simultaneously promoting bone regeneration. In this study, Zr-based large-pore hierarchical mesoporous metal-organic framework (MOF) nanoparticles (NPs) HMUiO-66-NH2 were successfully proposed as bifunctional nanomaterials for bone regeneration and ROS scavenging in periodontitis therapy. HMUiO-66-NH2 NPs demonstrated outstanding biocompatibility both in vitro and in vivo. Significantly, these NPs enhanced the osteogenic differentiation of bone mesenchymal stem cells (BMSCs) under normal and high ROS conditions, upregulating osteogenic gene expression and mitigating oxidative stress. Furthermore, in vivo imaging revealed a gradual degradation of HMUiO-66-NH2 NPs in periodontal tissues. Local injection of HMUiO-66-NH2 effectively reduced bone defects and ROS levels in periodontitis-induced C57BL/6 mice. RNA sequencing highlighted that differentially expressed genes (DEGs) are predominantly involved in bone tissue development, with notable upregulation in Wnt and TGF-β signaling pathways. In conclusion, HMUiO-66-NH2 exhibits dual functionality in alleviating oxidative stress and promoting bone repair, positioning it as an effective strategy against bone resorption in oxidative stress-related periodontitis.

Visualization of Diabetes Progression by an Activatable NIR-IIb Luminescent Probe

Developing NIR-IIb luminescence probes with rapid visualization and a high penetration depth is essential for diabetes research. Combining a sensitizing switch with lanthanide-doped nanoparticles (LnNPs) has been employed to fabricate the NIR-IIb probes. However, these probes mainly adopt heptamethine cyanine dye as the antenna, and the NIR-IIb signal is activated by inhibiting the photoinduced electron transfer (PET) of the dye. Due to limited recognition units, this strategy makes many biomolecules undetectable, such as cysteine (Cys), which is closely related to diabetes. Herein, in this article, hemicyanine dye, NFL-OH, was verified as a new antenna to sensitize NIR-IIb emission from LnNPs. Unlike traditional cyanine dyes, hemicyanine's fluorescence intensity can also be modulated by intramolecular charge transfer (ICT), thereby expanding the range of detectable targets for NIR-IIb probes based on sensitization mechanism. Through switching the hemicyanine-sensitized NIR-IIb emission, we successfully fabricated an NFL-Cys-LnNPs' nanoprobe, which can effectively monitor Cys concentration in the liver of diabetic mice during diabetes progression and evaluate the efficacy of diabetic drugs. Our work not only presents an excellent tool for Cys imaging but also introduces new concepts for designing NIR-IIb probes.

The Current Status and Future Directions on Nanoparticles for Tumor Molecular Imaging

Molecular imaging is an advanced technology that utilizes specific probes or markers in conjunction with cutting-edge imaging techniques to observe and analyze the localization, distribution, activity, and interactions of biomolecules within living organisms. Tumor molecular imaging, by enabling the visualization and quantification of molecular characteristics of tumor cells, facilitates a deeper and more comprehensive understanding of tumors, providing valuable insights for early diagnosis, treatment monitoring, and cancer biology research. However, the image quality of molecular imaging still requires improvement, and nanotechnology has significantly propelled the advancement of molecular imaging. Currently, nanoparticle-based tumor molecular imaging technologies encompass radionuclide imaging, fluorescence imaging, magnetic resonance imaging, ultrasound imaging, photoacoustic imaging, and multimodal imaging, among others. As our understanding of the tumor microenvironment deepens, the design of nanoparticle probes for tumor molecular imaging has also evolved, offering new perspectives and expanding the applications of tumor molecular imaging. Beyond diagnostics, there is a marked trend towards integrated diagnosis and therapy, with image-guided treatment playing a pivotal role. This includes image-guided surgery, photodynamic therapy, and chemodynamic therapy. Despite continuous advancements and innovative developments in molecular imaging, many of these remain in the experimental stage and require breakthroughs before they can be fully integrated into clinical practice.

Nanotechnology-assisted combination drug delivery: a progressive approach for the treatment of acute myeloid leukemia

Acute myeloid leukemia (AML), a heterogeneous hematopoietic cancer prevalent in adults, has been a leading cause of leukemia-associated deaths for decades. Despite advancements in understanding its pathology and pharmacological targets, therapeutic strategies have seen minimal change. The standard treatment, combining cytarabine and anthracycline, has persisted, accompanied by challenges such as pharmacokinetic issues and non-specific drug delivery, leading to severe side effects. Nanotechnology offers a promising solution through combination drug delivery. FDA-approved CPX351 (VYXEOS™) a liposomal formulation delivering doxorubicin and cytarabine, exemplifies enhanced therapeutic efficacy. Ongoing research explores various nanocarriers for delivering multiple bioactives, addressing drug targeting, pharmacokinetics and chemoresistance. This review highlights nanotechnology-based combination therapies for the effective management of AML, presenting a potential breakthrough in leukemia.

Remote Control of Energy Transformation-Based Cancer Imaging and Therapy

Cancer treatment requires precise tumor-specific targeting at specific sites that allows for high-resolution diagnostic imaging and long-term patient-tailorable cancer therapy; while, minimizing side effects largely arising from non-targetability. This can be realized by harnessing exogenous remote stimuli, such as tissue-penetrative ultrasound, magnetic field, light, and radiation, that enable local activation for cancer imaging and therapy in deep tumors. A myriad of nanomedicines can be efficiently activated when the energy of such remote stimuli can be transformed into another type of energy. This review discusses the remote control of energy transformation for targetable, efficient, and long-term cancer imaging and therapy. Such ultrasonic, magnetic, photonic, radiative, and radioactive energy can be transformed into mechanical, thermal, chemical, and radiative energy to enable a variety of cancer imaging and treatment modalities. The current review article describes multimodal energy transformation where a serial cascade or multiple types of energy transformation occur. This review includes not only mechanical, chemical, hyperthermia, and radiation therapy but also emerging thermoelectric, pyroelectric, and piezoelectric therapies for cancer treatment. It also illustrates ultrasound, magnetic resonance, fluorescence, computed tomography, photoluminescence, and photoacoustic imaging-guided cancer therapies. It highlights afterglow imaging that can eliminate autofluorescence for sustained signal emission after the excitation.

A Wireless, Multicolor Fluorescence Image Sensor Implant for Real-Time Monitoring in Cancer Therapy

Real-time monitoring of dynamic biological processes in the body is critical to understanding disease progression and treatment response. This data, for instance, can help address the lower than 50% response rates to cancer immunotherapy. However, current clinical imaging modalities lack the molecular contrast, resolution, and chronic usability for rapid and accurate response assessments. Here, we present a fully wireless image sensor featuring a 2.5×5 mm2 CMOS integrated circuit for multicolor fluorescence imaging deep in tissue. The sensor operates wirelessly via ultrasound (US) at 5 cm depth in oil, harvesting energy with 221 mW/cm2 incident US power density (31% of FDA limits) and backscattering data at 13 kbps with a bit error rate <10-6. In-situ fluorescence excitation is provided by micro-laser diodes controlled with a programmable on-chip driver. An optical frontend combining a multi-bandpass interference filter and a fiber optic plate provides >6 OD excitation blocking and enables three-color imaging for detecting multiple cell types. A 36×40-pixel array captures images with <125 μm resolution. We demonstrate wireless, dual-color fluorescence imaging of both effector and suppressor immune cells in ex vivo mouse tumor samples with and without immunotherapy. These results show promise for providing rapid insight into therapeutic response and resistance, guiding personalized medicine.

NIR-II light in clinical oncology: opportunities and challenges

Novel strategies utilizing light in the second near-infrared region (NIR-II; 900-1,880 nm wavelengths) offer the potential to visualize and treat solid tumours with enhanced precision. Over the past few decades, numerous techniques leveraging NIR-II light have been developed with the aim of precisely eliminating tumours while maximally preserving organ function. During cancer surgery, NIR-II optical imaging enables the visualization of clinically occult lesions and surrounding vital structures with increased sensitivity and resolution, thereby enhancing surgical quality and improving patient prognosis. Furthermore, the use of NIR-II light promises to improve cancer phototherapy by enabling the selective delivery of increased therapeutic energy to tissues at greater depths. Initial clinical studies of NIR-II-based imaging and phototherapy have indicated impressive potential to decrease cancer recurrence, reduce complications and prolong survival. Despite the encouraging results achieved, clinical translation of innovative NIR-II techniques remains challenging and inefficient; multidisciplinary cooperation is necessary to bridge the gap between preclinical research and clinical practice, and thus accelerate the translation of technical advances into clinical benefits. In this Review, we summarize the available clinical data on NIR-II-based imaging and phototherapy, demonstrating the feasibility and utility of integrating these technologies into the treatment of cancer. We also introduce emerging NIR-II-based approaches with substantial potential to further enhance patient outcomes, while also highlighting the challenges associated with imminent clinical studies of these modalities.

Seizing the fate of lymph nodes in immunotherapy: To preserve or not?

Lymph node dissection has been a long-standing diagnostic and therapeutic strategy for metastatic cancers. However, questions over myriad related complications and survival outcomes are continuously debated. Immunotherapy, particularly neoadjuvant immunotherapy, has revolutionized the conventional paradigm of cancer treatment, yet has benefited only a fraction of patients. Emerging evidence has unveiled the role of lymph nodes as pivotal responders to immunotherapy, whose absence may contribute to drastic impairment in treatment efficacy, again posing challenges over excessive lymph node dissection. Hence, centering around this theme, we concentrate on the mechanisms of immune activation in lymph nodes and provide an overview of minimally invasive lymph node metastasis diagnosis, current best practices for activating lymph nodes, and the prognostic outcomes of omitting lymph node dissection. In particular, we discuss the potential for future comprehensive cancer treatment with effective activation of immunotherapy driven by lymph node preservation and highlight the challenges ahead to achieve this goal.

Single Side-Chain-Modulatory of Hemicyanine for Optimized Fluorescence and Photoacoustic Dual-Modality Imaging of H2S In Vivo

Near-infrared fluorescence (NIRF)/photoacoustic (PA) dual-modality imaging integrated high-sensitivity fluorescence imaging with deep-penetration PA imaging has been recognized as a reliable tool for disease detection and diagnosis. However, it remains an immense challenge for a molecule probe to achieve the optimal NIRF and PA imaging by adjusting the energy allocation between radiative transition and nonradiative transition. Herein, a simple but effective strategy is reported to engineer a NIRF/PA dual-modality probe (Cl-HDN3) based on the near-infrared hemicyanine scaffold to optimize the energy allocation between radiative and nonradiative transition. Upon activation by H2S, the Cl-HDN3 shows a 3.6-fold enhancement in the PA signal and a 4.3-fold enhancement in the fluorescence signal. To achieve the sensitive and selective detection of H2S in vivo, the Cl-HDN3 is encapsulated within an amphiphilic lipid (DSPE-PEG2000) to form the Cl-HDN3-LP, which can successfully map the changes of H2S in a tumor-bearing mouse model with the NIRF/PA dual-modality imaging. This work presents a promising strategy for optimizing fluorescence and PA effects in a molecule probe, which may be extended to the NIRF/PA dual-modality imaging of other disease-relevant biomarkers.

Indocyanine Green-Labeled Platelets for Survival and Recovery Studies

Introduction

Before being implemented in daily clinical routine, new production strategies for platelet concentrates (PCs) must be validated for their efficacy. Besides in vitro testing, the establishment of new methods requires the labeling of platelets for in vivo studies of platelets' survival and recovery. Indocyanine green (ICG) is a Food and Drug Administration-approved near-infrared (NIR) fluorescent dye for diagnostic use in vivo, suitable for non-radioactive direct cell labeling of platelets.

Methods

Platelets from PCs in storage solutions with different plasma concentrations were labeled with ICG up to concentrations of 200 μm. Whole blood (WB) was used as an ex vivo matrix to monitor the labeling stability of ICG-labeled platelets. The impact of labeling processes was assessed by the quantification of CD62P expression and PAC-1 binding as platelet function markers. Platelet aggregation was analyzed by light transmission aggregometry. ICG-labeling efficiency and stability of platelets were determined by flow cytometry.

Results

Platelets from PCs could be successfully labeled with 10 μm ICG after 1 and 4 days of storage. The best labeling efficiency of 99.8% ± 0.1% (immediately after labeling) and 81% ± 6.2% (after 24 h incubation with WB) was achieved by plasma replacement by 100% platelet additive solution for the labeling process. Since the washing process slightly impaired platelet function, ICG labeling itself did not affect platelets. Immediately after the ICG-labeling process, plasma was re-added, resulting in a recovered platelet function.

Conclusion

We developed a Good Manufacturing Practice compatible protocol for ICG fluorescent platelet labeling suitable for survival and recovery studies in vivo as a non-radioactive labeling alternative.

From structural design to delivery: mRNA therapeutics for cancer immunotherapy

mRNA therapeutics have emerged as powerful tools for cancer immunotherapy in accordance with their superiority in expressing all sequence-known proteins in vivo. In particular, with a small dosage of delivered mRNA, antigen-presenting cells (APCs) can synthesize mutant neo-antigens and multi-antigens and present epitopes to T lymphocytes to elicit antitumor effects. In addition, expressing receptors like chimeric antigen receptor (CAR), T-cell receptor (TCR), CD134, and immune-modulating factors including cytokines, interferons, and antibodies in specific cells can enhance immunological response against tumors. With the maturation of in vitro transcription (IVT) technology, large-scale and pure mRNA encoding specific proteins can be synthesized quickly. However, the clinical translation of mRNA-based anticancer strategies is restricted by delivering mRNA into target organs or cells and the inadequate endosomal escape efficiency of mRNA. Recently, there have been some advances in mRNA-based cancer immunotherapy, which can be roughly classified as modifications of the mRNA structure and the development of delivery systems, especially the lipid nanoparticle platforms. In this review, the latest strategies for overcoming the limitations of mRNA-based cancer immunotherapies and the recent advances in delivering mRNA into specific organs and cells are summarized. Challenges and opportunities for clinical applications of mRNA-based cancer immunotherapy are also discussed.

Advances in Injectable Hydrogels Based on Diverse Gelation Methods for Biomedical Imaging

The injectable hydrogels can deliver the loads directly to the predetermined sites and form reservoirs to increase the enrichment and retention of the loads in the target areas. The preparation and injection of injectable hydrogels involve the sol-gel transformation of hydrogels, which is affected by factors such as temperature, ions, enzymes, light, mechanics (self-healing property), and pH. However, tracing the injection, degradation, and drug release from hydrogels based on different ways of gelation is a major concern. To solve this problem, contrast agents are introduced into injectable hydrogels, enabling the hydrogels to be imaged under techniques such as fluorescence imaging, photoacoustic imaging, magnetic resonance imaging, and radionuclide imaging. This review details methods for causing the gelation of imageable hydrogels; discusses the application of injectable hydrogels containing contrast agents in various imaging techniques, and finally explores the potential and challenges of imageable hydrogels based on different modes of gelation.

Recent Advances in Fluorescent Probes for Cancer Biomarker Detection

Many important biological species have been identified as cancer biomarkers and are gradually becoming reliable targets for early diagnosis and late therapeutic evaluation of cancer. However, accurate quantitative detection of cancer biomarkers remains challenging due to the complexity of biological systems and the diversity of cancer development. Fluorescent probes have been extensively utilized for identifying biological substances due to their notable benefits of being non-invasive, quickly responsive, highly sensitive and selective, allowing real-time visualization, and easily modifiable. This review critiques fluorescent probes used for detecting and imaging cancer biomarkers over the last five years. Focuses are made on the design strategies of small-molecule and nano-sized fluorescent probes, the construction methods of fluorescence sensing and imaging platforms, and their further applications in detection of multiple biomarkers, including enzymes, reactive oxygen species, reactive sulfur species, and microenvironments. This review aims to guide the design and development of excellent cancer diagnostic fluorescent probes, and promote the broad application of fluorescence analysis in early cancer diagnosis.

Prognostic significance of RKIP, TGM2, and CMTM4 expression in oral squamous cell carcinoma

BACKGROUND

The expression of RKIP, TGM2, and CMTM4 in oral squamous cell carcinoma (OSCC) and normal oral tissues was detected and their correlations were analyzed. The relationships between RKIP, TGM2, and CMTM4 and the clinicopathological parameters and prognosis of patients were analyzed.

METHODS

Seventy cancerous and adjacent normal tissue samples were selected, recorded in the pathology department, and embedded in paraffin. Protein expression was detected by immunohistochemistry. Statistical software (SPSS 25.0, IBM Corporation) was used for the statistical analysis. The chi-squared (χ2) test was used to analyze the expression of RKIP, TGM2, and CMTM4 proteins and their clinicopathological features. Differences in RKIP, TGM2, and CMTM4 protein levels between OSCC and normal tissues were compared using a χ2 test. Survival analysis was performed using the Kaplan-Meier method, and differences between survival curves were determined using the log-rank test. The effects of RKIP, TGM2, and CMTM4 expression on patient prognosis were analyzed using a multivariate Cox proportional hazards regression model. P < .05 was considered statistically significant.

RESULTS

The expression level of RKIP correlated with age and clinical stage (P < .05). TGM2 was associated with clinical stage and lymph node metastasis (P < .05). The expression of CMTM4 increased with a decrease in cancer differentiation. Kaplan-Meier survival analysis suggested that the positive expression of TGM2 and CMTM4 may predict poor prognosis in patients with OSCC. The multivariate Cox proportional hazards regression model suggested that TGM2 could be an independent prognostic factor for patients with OSCC.

CONCLUSION

Combined expression of TGM2 and CMTM4 can be used as an indicator to evaluate the risk of metastasis and prognosis of OSCC.

Articular cartilage repair biomaterials: strategies and applications

Articular cartilage injury is a frequent worldwide disease, while effective treatment is urgently needed. Due to lack of blood vessels and nerves, the ability of cartilage to self-repair is limited. Despite the availability of various clinical treatments, unfavorable prognoses and complications remain prevalent. However, the advent of tissue engineering and regenerative medicine has generated considerable interests in using biomaterials for articular cartilage repair. Nevertheless, there remains a notable scarcity of comprehensive reviews that provide an in-depth exploration of the various strategies and applications. Herein, we present an overview of the primary biomaterials and bioactive substances from the tissue engineering perspective to repair articular cartilage. The strategies include regeneration, substitution, and immunization. We comprehensively delineate the influence of mechanically supportive scaffolds on cellular behavior, shedding light on emerging scaffold technologies, including stimuli-responsive smart scaffolds, 3D-printed scaffolds, and cartilage bionic scaffolds. Biologically active substances, including bioactive factors, stem cells, extracellular vesicles (EVs), and cartilage organoids, are elucidated for their roles in regulating the activity of chondrocytes. Furthermore, the composite bioactive scaffolds produced industrially to put into clinical use, are also explicitly presented. This review offers innovative solutions for treating articular cartilage ailments and emphasizes the potential of biomaterials for articular cartilage repair in clinical translation.

Light-Responsive and Dual-Targeting Liposomes: From Mechanisms to Targeting Strategies

In recent years, nanocarriers have played an ever-increasing role in clinical and biomedical applications owing to their unique physicochemical properties and surface functionalities. Lately, much effort has been directed towards the development of smart, stimuli-responsive nanocarriers that are capable of releasing their cargos in response to specific stimuli. These intelligent-responsive nanocarriers can be further surface-functionalized so as to achieve active tumor targeting in a sequential manner, which can be simply modulated by the stimuli. By applying this methodological approach, these intelligent-responsive nanocarriers can be directed to different target-specific organs, tissues, or cells and exhibit on-demand controlled drug release that may enhance therapeutic effectiveness and reduce systemic toxicity. Light, an external stimulus, is one of the most promising triggers for use in nanomedicine to stimulate on-demand drug release from nanocarriers. Light-triggered drug release can be achieved through light irradiation at different wavelengths, either in the UV, visible, or even NIR region, depending on the photophysical properties of the photo-responsive molecule embedded in the nanocarrier system, the structural characteristics, and the material composition of the nanocarrier system. In this review, we highlighted the emerging functional role of light in nanocarriers, with an emphasis on light-responsive liposomes and dual-targeted stimuli-responsive liposomes. Moreover, we provided the most up-to-date photo-triggered targeting strategies and mechanisms of light-triggered drug release from liposomes and NIR-responsive nanocarriers. Lastly, we addressed the current challenges, advances, and future perspectives for the deployment of light-responsive liposomes in targeted drug delivery and therapy.

Photophysical Characterization and Biointeractions of NIR Squaraine Dyes for in Vitro and in Vivo Bioimaging

The increasing demand for reliable near-infrared (NIR) probes exhibiting enduring fluorescence in living systems and facile compatibility with biomolecules such as peptides, antibodies or proteins is driven by the increasing use of NIR imaging in clinical diagnostics. To address this demand, a series of carboxy-functionalized unsymmetrical squaraine dyes (SQ-27, SQ-212, and SQ-215) along with non-carboxy-functionalized SQ-218 absorbing and emitting in the NIR wavelength range were designed and synthesized followed by photophysical characterization. This study focused on the impact of structural variations in the alkyl chain length, carboxy functionality positioning, and spacer chain length on dye aggregation and interaction with bovine serum albumin (BSA) as a model protein. In phosphate buffer (PB), the absorption intensity of the dyes markedly decreased accompanied by pronounced shoulders indicative of dye aggregation, and complete fluorescence quenching was seen in contrast to organic solvents. However, in the presence of BSA in PB, there was a enhancement in absorption intensity while regaining the fluorescence coupled with a remarkable increase in the intensity with increasing BSA concentrations, signifying the impact of dye-BSA interactions on preventing aggregation. Further analysis of Job's plot unveiled a 2:1 interaction ratio between BSA and all dyes, while the binding studies revealed a robust binding affinity (Ka) in the order of 107/mol. SQ-212 and SQ-215 were further tested for their in vitro and in vivo imaging capabilities. Notably, SQ-212 demonstrated nonpermeability to cells, while SQ-215 exhibited easy penetration and prominent cytoplasmic localization in in vitro studies. Injection of the dyes into laboratory mice showcased their efficacy in visualization, displaying stable and intense fluorescence in tissues without toxicity, organ damage, or behavioral changes. Thus, SQ-212 and SQ-215 are promising candidates for imaging applications, holding potential for noninvasive cellular and diagnostic imaging as well as biomarker detection when coupled with specific vectors in living systems.

ImmunoPET provides a novel way to visualize the CD103+ tissue-resident memory T cell to predict the response of immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) have made significant progress in oncotherapy improving survival of patients. However, the benefits are limited to only a small subgroup of patients who could achieve durable responses. Early prediction of response may enable treatment optimization and patient stratification. Therefore, developing appropriate biomarkers is critical to monitoring efficacy and assessing patient response to ICIs.

MAIN BODY

Herein, we first introduce a new potential biomarker, CD103, expressed on tissue-resident memory T cells, and discuss the potential application of CD103 PET imaging in predicting immune checkpoint inhibitor treatment. In addition, we describe the current targets of ImmunoPET and compare these targets with CD103. To assess the benefit of PET imaging, a comparative analysis between ImmunoPET and other imaging techniques commonly employed for tumor diagnosis was performed. Additionally, we compare ImmunoPET and immunohistochemistry (IHC), a widely utilized clinical method for biomarker identification with respect to visualizing the immune targets.

CONCLUSION

CD103 ImmunoPET is a promising method for determining tumor-infiltrating lymphocytes (TILs) load and response to ICIs, thereby addressing the lack of reliable biomarkers in cancer immunotherapy. Compared to general T cell markers, CD103 is a specific marker for tissue-resident memory T cells, which number increases during successful ICI therapy. ImmunoPET offers noninvasive, dynamic imaging of specific markers, complemented by detailed molecular information from immunohistochemistry (IHC). Radiomics can extract quantitative features from traditional imaging methods, while near-infrared fluorescence (NIRF) imaging aids tumor detection during surgery. In the era of precision medicine, combining such methods will offer a more comprehensive approach to cancer diagnosis and treatment.

A near-infrared fluorescent probe for viscosity: Differentiating cancer cells from normal cells and dual-modal imaging in tumor mice

As a basic parameter of the intracellular microenvironment, viscosity is closely related to the development of cancer. Thus, it is necessary to utilize a sensitive tool to visualize the viscosity in tumor cells and mice, which is helpful for the diagnosis of cancer. Herein, a novel dual-modal probe (IX-V) that has a near-infrared fluorescence (NIRF) and photoacoustic (PA) response to viscosity is synthesized. In low viscosity media, the probe has no fluorescence. With the increase of viscosity, the fluorescence is produced in the near-infrared region due to the inhibition of the TICT process. At the same time, the probe shows different photoacoustic (PA) signals in different viscosity media. Most notably, the viscosity in tumor cells has been imaged successfully by the application of IX-V, and the probe can effectively distinguish cancer cells from normal cells co-cultured in one dish by the difference of fluorescence intensity. In addition, the probe has been used for dual-modal imaging (NIRF and PA) of viscosity in tumor mice, which provides a tool for exploring the relationship between viscosity and diseases. That is to say, IX-V can achieve complementary imaging effects and has great application prospects in the tumor diagnosis.

J-Aggregation Strategy toward Potentiated NIR-II Fluorescence Bioimaging of Molecular Fluorophores

Molecular fluorophores emitting in the second near-infrared (NIR-II, 1000-1700 nm) window with strong optical harvesting and high quantum yields hold great potential for in vivo deep-tissue bioimaging and high-resolution biosensing. Recently, J-aggregates are harnessed to engineer long-wavelength NIR-II emitters and show unique superiority in tumor detection, vessel mapping, surgical navigation, and phototheranostics due to their bathochromic-shifted optical bands in the required slip-stacked arrangement aggregation state. However, despite the preliminary progress of NIR-II J-aggregates and theoretical study of structure-property relationships, further paradigms of NIR-II J-aggregates remain scarce due to the lack of study on aggregated fluorophores with slip-stacked fashion. In this effort, how to utilize the specific molecular structure to form slip-stacked packing motifs with J-type aggregated exciton coupling is emphatically elucidated. First, several molecular regulating strategies to achieve NIR-II J-aggregates containing intermolecular interactions and external conditions are positively summarized and deeply analyzed. Then, the recent reports on J-aggregates for NIR-II bioimaging and theranostics are systematically summarized to provide a clear reference and direction for promoting the development of NIR-II organic fluorophores. Eventually, the prospective efforts on ameliorating and promoting NIR-II J-aggregates to further clinical practices are outlined.

Near-Infrared Fluorescence Imaging of miRNA Using a Transmembrane Polypeptide-Based Genetic Reporter

MicroRNAs (miRNAs) are small noncoding RNAs that play important regulatory roles in multiple biological processes. Many miRNAs exhibit unique expression patterns and are considered as theranostic biomarkers in a variety of human diseases. A reporter system that is capable of imaging miRNA in vivo is crucial for investigating miRNA biology. In the present study, an organic anion-transporting polypeptide 1B3 (OATP1B3)-based genetic switch system is designed and optimized to achieve near-infrared fluorescent imaging of miRNA by the uptake of indocyanine green (ICG) dye. The reporter system, named miR-ON-OB3, is shown to be efficient to regulate the expression of OATP1B3 in mammalian cells. Notably, the results indicate that the system is of high sensitivity for near-infrared fluorescence imaging of both exogenous and endogenous miRNA in mammalian cells. Moreover, the system is proved to be functional for real-time near-infrared fluorescence imaging of miRNA in living mice. This study establishes a novel genetic encoded reporter for near-infrared fluorescence imaging of miRNA, which may provide a potential tool for in vivo imaging of miRNA in clinical applications due to the clinical availability of ICG.

Bioorthogonal Guided Activation of cGAS-STING by AIE Photosensitizer Nanoparticles for Targeted Tumor Therapy and Imaging

Photodynamic therapy (PDT) and photothermal therapy (PTT) leverage reactive oxygen species (ROS) and control local hyperthermia by photosensitizer to perturb intracellular redox equilibrium, inducing DNA damage in both mitochondria and nucleus, activating the cGAS-STING pathway, ultimately eliciting antitumor immune responses. However, current photosensitizers are encumbered by limitations such as suboptimal tumor targeting, aggregation-caused quenching (ACQ), and restricted excitation and emission wavelengths. Here, this work designs novel nanoparticles based on aggregation-induced emission (AIE) photosensitizer (BODTPE) for targeted tumor therapy and near-infrared II fluorescence imaging (NIR-II FLI) with enhanced PDT/PTT effects. BODTPE is employed as a monomer, dibenzocyclooctyne (DBCO)-PEG2k -amine serving as an end-capping polymer, to synthesize a BODTPE-containing polymer (DBD). Further, through self-assembly, DBD and mPEG-DSPE2k combined to form nanoparticles (NP-DBD). Notably, the DBCO on the surface of NP-DBD can react with azide groups on cancer cells pretreated with Ac4 ManNAz through a copper-free click reaction. This innovative formulation led to targeted accumulation of NP-DBD within tumor sites, a phenomenon convincingly demonstrated in murine tumor models subjected to N-azidoacetylmannosamine-tetraacylated (Ac4 ManNAz) pretreatment. Significantly, NP-DBD exhibits a multifaceted effect encompassing PDT/PTT/NIR-II FLI upon 808 nm laser irradiation, thereby better activating the cGAS-STING pathway, culminating in a compelling tumor inhibition effect augmented by robust immune modulation.

Colon targeted releases and uptakes of paclitaxel loaded in modified porous starch

Hyaluronic acid can modify porous starch through cross-linking and hydrogen bonding, effectively achieving a paclitaxel entrapment efficiency of ∼92 % and drug loading of ∼23 %. In this study, the pores and intergranular gaps of porous starch were filled with paclitaxel under solvent volatilization, and the enrichment process and its characteristics were recorded using a microscope. The paclitaxel-loaded particles were coated with chitosan-phytic acid to target the colon. In vivo imaging in mice showed that the capsule released paclitaxel in the colon rather than in the upper digestive tract, and the paclitaxel distribution in the main organs at 24 h was significantly lower than that of raw paclitaxel. Hyaluronic acid-modified porous starch can target cancer cells. Cell internalization of paclitaxel mediated by hyaluronic acid was approximately 1.97 times that of raw paclitaxel, higher than that of receptor-shielded cells and cells incubated with unmodified carriers, as evidenced by the accumulation of fluorescent paclitaxel in the nucleus and marked cell apoptosis. The hyaluronic acid-modified porous starch system is an effective method for the high-load and targeted release of hydrophobic anticancer drugs.

Near-infrared photodynamic and photothermal co-therapy based on organic small molecular dyes

Near-infrared (NIR) organic small molecule dyes (OSMDs) are effective photothermal agents for photothermal therapy (PTT) due to their advantages of low cost and toxicity, good biodegradation, and strong NIR absorption over a wide wavelength range. Nevertheless, OSMDs have limited applicability in PTT due to their low photothermal conversion efficiency and inadequate destruction of tumor regions that are nonirradiated by NIR light. However, they can also act as photosensitizers (PSs) to produce reactive oxygen species (ROS), which can be further eradicated by using ROS-related therapies to address the above limitations of PTT. In this review, the synergistic mechanism, composition, and properties of photodynamic therapy (PDT)-PTT nanoplatforms were comprehensively discussed. In addition, some specific strategies for further improving the combined PTT and PDT based on OSMDs for cancer to completely eradicate cancer cells were outlined. These strategies include performing image-guided co-therapy, enhancing tumor infiltration, increasing H2O2 or O2 in the tumor microenvironment, and loading anticancer drugs onto nanoplatforms to enable combined therapy with phototherapy and chemotherapy. Meanwhile, the intriguing prospects and challenges of this treatment modality were also summarized with a focus on the future trends of its clinical application.

Diagnosing Orthotopic Lung Tumor Using a NTR-Activatable Near-Infrared Fluorescent Probe by Tracheal Inhalation

Nitroreductase (NTR) is an enzyme that is upregulated under tumor-depleted oxygen conditions. The majority of studies have been conducted on NTR, but many existing fluorescent imaging tools for monitoring NTR inevitably suffer from weak targeting, low sensitivity, and simple tumor models. Research on diagnosing lung tumors has been very popular in recent years, but targeting assays in orthotopic lung tumors is still of great research value, as such models better mimic the reality of cancer in the organism. Here, we developed a novel near-infrared (NIR) fluorescent probe IR-ABS that jointly targets NTR and carbonic anhydrase IX (CAIX). IR-ABS has excellent sensitivity and selectivity and shows exceptional NTR response in spectroscopic tests. The measurements ensured that this probe has good biosafety in both cells and mice. A better NTR response was found in hypoxic tumor cells at the cellular level, distinguishing tumor cells from normal cells. In vivo experiments demonstrated that IR-ABS achieves a hypoxic response at the zebrafish level and enables rapid and accurate tumor margin distinguishment in different mouse tumor models. More importantly, we successfully applied IR-ABS for NTR detection in orthotopic lung tumor models, further combined with tracheal inhalation drug delivery to improve targeting. To the best of our knowledge, we present for the first time a near-infrared imaging method for targeting lung cancerous tumor in situ via tracheal inhalation drug delivery, in contrast to the reported literature. This NIR fluorescence diagnostic strategy for targeting orthotopic lung cancer holds exciting potential for clinical aid in cancer diagnosis.

Selective Accumulation of Near Infrared-Labeled Multivalent Quinidine Copolymers in Tumors Overexpressing P-Glycoprotein: Potential for Noninvasive Diagnostic Imaging

P-glycoprotein (P-gp) is a promiscuous small molecule transporter whose overexpression in cancer is associated with multidrug resistance (MDR). In these instances, anticancer drugs can select for P-gp-overexpressing cells, leading to cancer recurrence with an MDR phenotype. To avoid selection for MDR cancers and inform individual patient treatment plans, it is critical to noninvasively identify P-gp-overexpressing tumors prior to administration of chemotherapy. We report the facile free radical copolymerization of quinidine, a competitive inhibitor of P-gp, and acrylic acid to generate multiplexed polymeric P-gp-targeted imaging agents with tunable quinidine content. Copolymer targeting was demonstrated in a nude mouse xenograft model. In xenografts overexpressing P-gp, copolymer distribution was enhanced over two-fold compared to the negative control of poly(acrylic acid) regardless of quinidine content. In contrast, accumulation of the copolymers in xenografts lacking P-gp was equivalent to poly(acrylic acid). This work forms the foundation for a unique approach toward the phenotype-specific noninvasive imaging of MDR tumors and is the first in vivo demonstration of copolymer accumulation through the active targeting of P-gp.

Theranostic chimeric antigen receptor (CAR)-T cells: Insight into recent trends and challenges in solid tumors

Cell therapy has reached significant milestones in various life-threatening diseases, including cancer. Cell therapy using fluorescent and radiolabeled chimeric antigen receptor (CAR)-T cell is a successful strategy for diagnosing or treating malignancies. Since cell therapy approaches have different results in cancers, the success of hematological cancers has yet to transfer to solid tumor therapy, leading to more casualties. Therefore, there are many areas for improvement in the cell therapy platform. Understanding the therapeutic barriers associated with solid cancers through cell tracking and molecular imaging may provide a platform for effectively delivering CAR-T cells into solid tumors. This review describes CAR-T cells' role in treating solid and non-solid tumors and recent advances. Furthermore, we discuss the main obstacles, mechanism of action, novel strategies and solutions to overcome the challenges from molecular imaging and cell tracking perspectives.

A Highly Selective Mn(II)-Specific DNAzyme and Its Application in Intracellular Sensing

Manganese is an essential trace element in the human body that acts as a cofactor in many enzymes and metabolisms. It is important to develop methods to detect Mn²⁺ in living cells. While fluorescent sensors have been very effective in detecting other metal ions, Mn²⁺-specific fluorescent sensors are rarely reported due to nonspecific fluorescence quenching by the paramagnetism of Mn²⁺ and poor selectivity against other metal ions such as Ca²⁺ and Mg²⁺. To address these issues, we herein report in vitro selection of an RNA-cleaving DNAzyme with exceptionally high selectivity for Mn²⁺. Through converting it into a fluorescent sensor using a catalytic beacon approach, Mn²⁺ sensing in immune cells and tumor cells has been achieved. The sensor is also used to monitor degradation of manganese-based nanomaterials such as MnOx in tumor cells. Therefore, this work provides an excellent tool to detect Mn²⁺ in biological systems and monitor the Mn²⁺-involved immune response and antitumor therapy.

Molecular Imaging of Innate Immunity and Immunotherapy

The innate immune system plays a key role as the first line of defense in various human diseases including cancer, cardiovascular and inflammatory diseases. In contrast to tissue biopsies and blood biopsies, in vivo imaging of the innate immune system can provide whole body measurements of immune cell location and function and changes in response to disease progression and therapy. Rationally developed molecular imaging strategies can be used in evaluating the status and spatio-temporal distributions of the innate immune cells in near real-time, mapping the biodistribution of novel innate immunotherapies, monitoring their efficacy and potential toxicities, and eventually for stratifying patients that are likely to benefit from these immunotherapies. In this review, we will highlight the current state-of-the-art in noninvasive imaging techniques for preclinical imaging of the innate immune system particularly focusing on cell trafficking, biodistribution, as well as pharmacokinetics and dynamics of promising immunotherapies in cancer and other diseases; discuss the unmet needs and current challenges in integrating imaging modalities and immunology and suggest potential solutions to overcome these barriers.

NIR-II Imaging and Sandwiched Plasmonic Biosensor for Ultrasensitive Intraoperative Definition of Tumor-Invaded Lymph Nodes

Radical lymphadenectomy remains the cornerstone of preventing tumor metastasis through the lymphatic system. Current surgical resection of lymph nodes (LNs) based on fluorescence-guided surgery (FGS) suffers from low sensitivity/selectivity with only qualitative information, hampering accurate intraoperative decision-making. Herein, we develop a modularized theranostic system including NIR-II FGS and a sandwiched plasmonic chip (SPC). Intraoperative NIR-II FGS and detection of tumor-positive lymph nodes were performed on the gastric tumor to determine the feasibility of the modularized theranostic system in defining LN metastasis. Under the NIR-II imaging window, the orthotopic tumor and sentinel lymph nodes (SLNs) were successfully excised without ambient light interference in the operating room. Importantly, the SPC biosensor achieved 100% sensitivity and 100% specificity for tumor markers and realized rapid and high-throughput intraoperative SLN detection. We propose the synergetic design of combining the NIR-II FGS and suitable biosensor will substantially improve the efficiency of cancer diagnosis and therapy follow-up.

In Vivo Fate of CXCR2-Overexpressing Mesenchymal Stromal/Stem Cells in Pulmonary Diseases Monitored by Near-Infrared Region 2 Imaging

Lung-associated diseases pose a huge threat to human society. Mesenchymal stromal/stem cells (MSCs) hold great promise in the treatment of pulmonary diseases through cell transdifferentiation, paracrine factors, immune regulation, EV secretion, and drug loading. However, intravenous injection of MSCs often resulted in limited lesion tropism and apparent off-target accumulation. The IL-8-CXCR1/2 chemokine axis has been shown to be involved in progression of diseases including lung cancer and acute lung injury (ALI). Herein, we took advantage of this chemokine axis to enhance the homing of MSCs to cancerous and inflammation lesions. The in vivo distribution of MSCs was further monitored real-time by near-infrared region 2 (NIR-II) imaging owing to its outstanding performance in deep tissue imaging. Specifically, a new high-brightness D-A-D NIR-II dye, LJ-858, was synthesized and coprecipitated with a poly(d,l-lactic acid) polymer to form LJ-858 nanoparticles (NPs) with a relative quantum yield of 14.978%. LJ-858 NPs can efficiently label MSCs, and the NIR-II signal can be stable for 14 days without compromising the cell viability. Subcutaneous tracking of labeled MSCs showed no significant decline of NIR-II intensity within 24 h. The enhanced tropism of CXCR2-overexpressing MSCs to A549 tumor cells and the inflamed lung tissue was demonstrated through transwell models. The in vivo and ex vivo NIR-II imaging results further validated the significantly enhanced lesion retention of MSC^CXCR2 in the lung cancer and ALI models. Taken together, this work reported a robust strategy to enhance the pulmonary disease tropism by the IL-8-CXCR1/2 chemokine axis. In addition, in vivo distribution of MSCs was successfully visualized by NIR-II imaging, which provides more insights into optimizing protocols for MSC-based therapies in the future.

Molecularly Stimuli-Responsive Self-Assembled Peptide Nanoparticles for Targeted Imaging and Therapy

Self-assembly has emerged as an extensively used method for constructing biomaterials with sizes ranging from nanometers to micrometers. Peptides have been extensively investigated for self-assembly. They are widely applied owing to their desirable biocompatibility, biodegradability, and tunable architecture. The development of peptide-based nanoparticles often requires complex synthetic processes involving chemical modification and supramolecular self-assembly. Stimuli-responsive peptide nanoparticles, also termed "smart" nanoparticles, capable of conformational and chemical changes in response to stimuli, have emerged as a class of promising materials. These smart nanoparticles find a diverse range of biomedical applications, including drug delivery, diagnostics, and biosensors. Stimuli-responsive systems include external stimuli (such as light, temperature, ultrasound, and magnetic fields) and internal stimuli (such as pH, redox environment, salt concentration, and biomarkers), facilitating the generation of a library of self-assembled biomaterials for biomedical imaging and therapy. Thus, in this review, we mainly focus on peptide-based nanoparticles built by self-assembly strategy and systematically discuss their mechanisms in response to various stimuli. Furthermore, we summarize the diverse range of biomedical applications of peptide-based nanomaterials, including diagnosis and therapy, to demonstrate their potential for medical translation.

Low-Dose NIR-II Preclinical Bioimaging Using Liposome-Encapsulated Cyanine Dyes

Fluorescence imaging in the second near-infrared window (NIR-II, 1000-1700 nm) provides a powerful tool for in vivo structural and functional imaging in deep tissue. However, the lack of biocompatible contrast agents with bright NIR-II emission has hindered its application in fundamental research and clinical trials. Herein, a liposome encapsulation strategy for generating ultrabright liposome-cyanine dyes by restricting dyes in the hydrophobic pockets of lipids and inhibiting the aggregation, as corroborated by computational modeling, is reported. Compared with free indocyanine green (ICG, an US Food and Drug Administration-approved cyanine dye), liposome-encapsulated ICG (S-Lipo-ICG) shows a 38.7-fold increase in NIR-II brightness and enables cerebrovascular imaging at only one-tenth dose over a long period (30 min). By adjusting the excitation wavelength, two liposome-encapsulated cyanine dyes (S-Lipo-ICG and S-Lipo-FD1080) enable NIR-II dual-color imaging. Moreover, small tumor nodules (2-5 mm) can be successfully distinguished and removed with S-Lipo-ICG image-guided tumor surgery in rabbit models. This liposome encapsulation maintains the metabolic pathway of ICG, promising for clinical implementation.

N-methyl-d-aspartate receptors induce M1 polarization of macrophages: Feasibility of targeted imaging in inflammatory response in vivo

Background

N-methyl-d-aspartate receptors (NMDARs) are considered to be involved in several physiological and pathophysiological processes in addition to the progression of neurological disorders. However, how NMDARs are involved in the glycolytic phenotype of M1 macrophage polarization and the possibility of using them as a bio-imaging probe for macrophage-mediated inflammation remain unclear.

Methods

We analyzed cellular responses to NMDAR antagonism and small interfering RNAs using mouse bone marrow-derived macrophages (BMDMs) treated with lipopolysaccharide (LPS). An NMDAR targeting imaging probe, N-TIP, was produced via the introduction of NMDAR antibody and the infrared fluorescent dye FSD Fluor™ 647. N-TIP binding efficiency was tested in intact and LPS-stimulated BMDMs. N-TIP was intravenously administered to mice with carrageenan (CG)- and LPS-induced paw edema, and in vivo fluorescence imaging was conducted. The anti-inflammatory effects of dexamethasone were evaluated using the N-TIP-mediated macrophage imaging technique.

Results

NMDARs were overexpressed in LPS-treated macrophages, subsequently inducing M1 macrophage polarization. Mechanistically, NMDAR-mediated Ca2+ accumulation resulted in LPS-stimulated glycolysis via upregulation of PI3K/AKT/mTORC1 signaling. In vivo fluorescence imaging with N-TIP showed LPS- and CG-induced inflamed lesions at 5 h post-inflammation, and the inflamed lesions could be detected until 24 h. Furthermore, our N-TIP-mediated macrophage imaging technique helped successfully visualize the anti-inflammatory effects of dexamethasone in mice with inflammation.

Conclusion

This study demonstrates that NMDAR-mediated glycolysis plays a critical role in M1 macrophage-related inflammation. Moreover, our results suggest that NMDAR targeting imaging probe may be useful in research on inflammatory response in vivo.

Recent Development of Rhenium-Based Materials in the Application of Diagnosis and Tumor Therapy

Rhenium (Re) is widely used in the diagnosis and treatment of cancer due to its unique physical and chemical properties. Re has more valence electrons in its outer shell, allowing it to exist in a variety of oxidation states and to form different geometric configurations with many different ligands. The luminescence properties, lipophilicity, and cytotoxicity of complexes can be adjusted by changing the ligand of Re. This article mainly reviews the development of radionuclide 188Re in radiotherapy and some innovative applications of Re as well as the different therapeutic approaches and imaging techniques used in cancer therapy. In addition, the current application and future challenges and opportunities of Re are also discussed.

Dual-modal molecular imaging and therapeutic evaluation of coronary microvascular dysfunction using indocyanine green-doped targeted microbubbles

Coronary microvascular dysfunction (CMD), which causes a series of cardiovascular diseases, seriously endangers human health. However, precision diagnosis of CMD is still challenging due to the lack of sensitive probes and complementary imaging technologies. Herein, we demonstrate indocyanine green-doped targeted microbubbles (named T-MBs-ICG) as dual-modal probes for highly sensitive near-infrared (NIR) fluorescence imaging and high-resolution ultrasound imaging of CMD in mouse models. In vitro results show that T-MBs-ICG can specifically target fibrin, a specific CMD biomarker, via the cysteine-arginine-glutamate-lysine-alanine (CREKA) peptide modified on the surface of microbubbles. We further employ T-MBs-ICG to achieve NIR fluorescence imaging of injured myocardial tissue in a CMD mouse model, leading to a signal-to-background ratio (SBR) of up to 50, which is 20 fold higher than that of the non-targeted group. Furthermore, ultrasound molecular imaging of T-MBs-ICG is obtained within 60 s after intravenous injection, providing molecular information on ventricular and myocardial structures and fibrin with a resolution of 1.033 mm × 0.466 mm. More importantly, we utilize comprehensive dual-modal imaging of T-MBs-ICG to evaluate the therapeutic efficacy of rosuvastatin, a cardiovascular drug for the clinical treatment of CMD. Overall, the developed T-MBs-ICG probes with good biocompatibility exhibit great potential in the clinical diagnosis of CMD.

Dynamic interaction of injected liquid jet with skin layer interfaces revealed by microsecond imaging of optically cleared ex vivo skin tissue model

BACKGROUND

Needle-free jet injection (NFJI) systems enable a controlled and targeted delivery of drugs into skin tissue. However, a scarce understanding of their underlying mechanisms has been a major deterrent to the development of an efficient system. Primarily, the lack of a suitable visualization technique that could capture the dynamics of the injected fluid-tissue interaction with a microsecond range temporal resolution has emerged as a main limitation. A conventional needle-free injection system may inject the fluids within a few milliseconds and may need a temporal resolution in the microsecond range for obtaining the required images. However, the presently available imaging techniques for skin tissue visualization fail to achieve these required spatial and temporal resolutions. Previous studies on injected fluid-tissue interaction dynamics were conducted using in vitro media with a stiffness similar to that of skin tissue. However, these media are poor substitutes for real skin tissue, and the need for an imaging technique having ex vivo or in vivo imaging capability has been echoed in the previous reports.

METHODS

A near-infrared imaging technique that utilizes the optical absorption and fluorescence emission of indocyanine green dye, coupled with a tissue clearing technique, was developed for visualizing a NFJI in an ex vivo porcine skin tissue.

RESULTS

The optimal imaging conditions obtained by considering the optical properties of the developed system and mechanical properties of the cleared ex vivo samples are presented. Crucial information on the dynamic interaction of the injected liquid jet with the ex vivo skin tissue layers and their interfaces could be obtained.

CONCLUSIONS

The reported technique can be instrumental for understanding the injection mechanism and for the development of an efficient transdermal NFJI system as well.

A near-infrared fluorescent probe for monitoring abnormal mitochondrial viscosity in cancer and fatty-liver mice model

Viscosity is an important component of cell microenvironment, and abnormal mitochondrial viscosity is associated with many diseases such as tumor and fatty liver. Herein, a near-infrared fluorescence probe (QX-V) based on quinoline-xanthene dye for detecting viscosity is constructed. In high viscosity medium, the free rotation of single bond is inhibited and the fluorescence is released. The probe shows high sensitivity together with good selectivity. Notably, QX-V has a long excitation wavelength (710 nm) and emission wavelength (786 nm). At the same time, the probe is a positively charged molecule that can target mitochondria. QX-V can not only distinguish cancer cells from normal cells, but also make a distinction between normal cells and fatty hepatocytes. In addition, QX-V is used to image viscosity abnormality in tumor-bearing mice. The probe also has a good ability to image viscosity abnormality caused by liver injury in fatty-liver mice.

Low-density lipoprotein: a versatile nanoscale platform for targeted delivery

Low-density lipoprotein (LDL) is a small lipoprotein that plays a vital role in controlling lipid metabolism. LDL has a delicate nanostructure with unique physicochemical properties: superior payload capacity, long residence time in circulation, excellent biocompatibility, smaller size, and natural targeting. In recent decades, the superiority and feasibility of LDL particles as targeted delivery carriers have attracted much attention. In this review, we introduce the structure, composition, advantages, defects, and reconstruction of LDL delivery systems, summarize their research status and progress in targeted diagnosis and therapy, and finally look forward to the clinical application of LDL as an effective delivery vehicle.

Organosilicon Fluorescent Materials

In the past few decades, organosilicon fluorescent materials have attracted great attention in the field of fluorescent materials not only due to their abundant and flexible structures, but also because of their intriguing fluorescence properties, distinct from silicon-free fluorescent materials. Considering their unique properties, they have found broad application prospects in the fields of chemosensor, bioimaging, light-emitting diodes, etc. However, a comprehensive review focusing on this field, from the perspective of their catalogs and applications, is still absent. In this review, organosilicon fluorescent materials are classified into two main types, organosilicon small molecules and polymers. The former includes fluorescent aryl silanes and siloxanes, and the latter are mainly fluorescent polysiloxanes. Their synthesis and applications are summarized. In particular, the function of silicon atoms in fluorescent materials is introduced. Finally, the development trend of organosilicon fluorescent materials is prospected.

Skin Cancer Pathobiology at a Glance: A Focus on Imaging Techniques and Their Potential for Improved Diagnosis and Surveillance in Clinical Cohorts

Early diagnosis is essential for completely eradicating skin cancer and maximizing patients' clinical benefits. Emerging optical imaging modalities such as reflectance confocal microscopy (RCM), optical coherence tomography (OCT), magnetic resonance imaging (MRI), near-infrared (NIR) bioimaging, positron emission tomography (PET), and their combinations provide non-invasive imaging data that may help in the early detection of cutaneous tumors and surgical planning. Hence, they seem appropriate for observing dynamic processes such as blood flow, immune cell activation, and tumor energy metabolism, which may be relevant for disease evolution. This review discusses the latest technological and methodological advances in imaging techniques that may be applied for skin cancer detection and monitoring. In the first instance, we will describe the principle and prospective clinical applications of the most commonly used imaging techniques, highlighting the challenges and opportunities of their implementation in the clinical setting. We will also highlight how imaging techniques may complement the molecular and histological approaches in sharpening the non-invasive skin characterization, laying the ground for more personalized approaches in skin cancer patients.

Imaging drug delivery to the lungs: Methods and applications in oncology

Direct delivery to the lung via inhalation is arguably one of the most logical approaches to treat lung cancer using drugs. However, despite significant efforts and investment in this area, this strategy has not progressed in clinical trials. Imaging drug delivery is a powerful tool to understand and develop novel drug delivery strategies. In this review we focus on imaging studies of drug delivery by the inhalation route, to provide a broad overview of the field to date and attempt to better understand the complexities of this route of administration and the significant barriers that it faces, as well as its advantages. We start with a discussion of the specific challenges for drug delivery to the lung via inhalation. We focus on the barriers that have prevented progress of this approach in oncology, as well as the most recent developments in this area. This is followed by a comprehensive overview of the different imaging modalities that are relevant to lung drug delivery, including nuclear imaging, X-ray imaging, magnetic resonance imaging, optical imaging and mass spectrometry imaging. For each of these modalities, examples from the literature where these techniques have been explored are provided. Finally the different applications of these technologies in oncology are discussed, focusing separately on small molecules and nanomedicines. We hope that this comprehensive review will be informative to the field and will guide the future preclinical and clinical development of this promising drug delivery strategy to maximise its therapeutic potential.

Effective design of organic luminogens for near-infrared-II fluorescence imaging and photo-mediated therapy

Due to their electron coupling capability, organic luminescent materials exhibit powerful optoelectronic features that are responsible for their light-harvesting and light-amplification properties. The extensive modification of conjugated systems has shown significant improvement in their photonic properties thus broadening their applicability in photo-mediated imaging and photo-based treatment. Organic luminogens with emission in the near-infrared second region are found attractive not only for their deeper penetrating power but also for accurate visual imaging superiority with higher temporal resolution and spatial resolution suitable for tumor precision treatment. In this review, we underscore the latest development in organic luminogens (conjugated polymers and small molecules), focusing on chemical design, molecular engineering, and their applications in the scope of bioimaging followed by photo-assisted treatment, including photodynamic therapy (PDT), photothermal therapy (PTT), and immunotherapy ablation. Organic luminogens integrated with an aggregation-induced emission feature significantly optimize their physicochemical properties to act as quintessential nanoplatforms for controllable image-guided therapy. In conclusion, we clarify the limitations and challenges and provide insights into how to design organic dyes with improved safety for potential clinical applications.

Pathological complete remission of relapsed tumor by photo-activating antibody-mimetic drug conjugate treatment

Antibody-mimetic drug conjugate is a novel noncovalent conjugate consisting of an antibody-mimetic recognizing a target molecule on the cancer cell surface and low-molecular-weight payloads that kill the cancer cells. In this study, the efficacy of a photo-activating antibody-mimetic drug conjugate targeting HER2-expressing tumors was evaluated in mice, by using the affibody that recognize HER2 (Z_HER2:342 ) as a target molecule and an axially substituted silicon phthalocyanine (a novel potent photo-activating compound) as a payload. The first treatment with the photo-activating antibody-mimetic drug conjugates reduced the size of all HER2-expressing KPL-4 xenograft tumors macroscopically. However, during the observation period, relapsed tumors gradually appeared in approximately 50% of the animals. To evaluate the efficacy of repeated antibody-mimetic drug conjugate treatment, animals with relapsed tumors were treated again with the same regimen. After the second observation period, the mouse tissues were examined histopathologically. Unexpectedly, all relapsed tumors were eradicated, and all animals were diagnosed with pathological complete remission. After the second treatment, skin wounds healed rapidly, and no significant side effects were observed in other organs, except for occasional microscopic granulomatous tissues beneath the serosa of the liver in a few mice. Repeated treatments seemed to be well tolerated. These results indicate the promising efficacy of the repeated photo-activating antibody-mimetic drug conjugate treatment against HER2-expressing tumors.

New insight into the application of fluorescence platforms in tumor diagnosis: From chemical basis to clinical application

Early and rapid diagnosis of tumors is essential for clinical treatment or management. In contrast to conventional means, bioimaging has the potential to accurately locate and diagnose tumors at an early stage. Fluorescent probe has been developed as an ideal tool to visualize tumor sites and to detect biological molecules which provides a requirement for noninvasive, real-time, precise, and specific visualization of structures and complex biochemical processes in vivo. Rencently, the development of synthetic organic chemistry and new materials have facilitated the development of near-infrared small molecular sensing platforms and nanoimaging platforms. This provides a competitive tool for various fields of bioimaging such as biological structure and function imaging, disease diagnosis, in situ at the in vivo level, and real-time dynamic imaging. This review systematically focused on the recent progress of small molecular near-infrared fluorescent probes and nano-fluorescent probes as new biomedical imaging tools in the past 3-5 years, and it covers the application of tumor biomarker sensing, tumor microenvironment imaging, and tumor vascular imaging, intraoperative guidance and as an integrated platform for diagnosis, aiming to provide guidance for researchers to design and develop future biomedical diagnostic tools.

A hemicyanine-based fluorescent probe for simultaneous imaging of Carboxylesterases and Histone deacetylases in hepatocellular carcinoma

Carboxylesterases (CESs) and Histone deacetylases (HDACs) are regarded as important signaling enzymes highly associated with the development and progression of multiple cancers, including hepatocellular carcinoma (HCC). In this work, a near-infrared (NIR) fluorescent probe named Lys-HXPI was designed and synthesized, which linked a hemicyanine dye and 6-acetamidohexanoic acid via an ester bond. Lys-HXPI displayed a remarkable increase with a NIR emission at 720 nm, a low detection limit (<10 nM) for HDAC1, HDAC 6, CES1 and CES2, as well as a high selectivity for the target enzymes over other relevant analytes. Furthermore, Lys-HXPI was used to image endogenous target enzymes in living cells, tumor-bearing nude mice and tissue slices. The ability of Lys-HXPI to simultaneous image CESs and HDACs was demonstrated with RT-qPCR and the confocal imaging in Hep G2 and MDA-MB-231. Taking advantage of NIR emission, the probe was also successfully applied to imaging Hep G2 tumor mice and tissue slices. Lys-HXPI is expected to be useful for the effective detecting of CESs and HDACs in complex biosystems.

Research progress on tumor hypoxia-associative nanomedicine

Hypoxia at the solid tumor site is generally related to the unrestricted proliferation and metabolism of cancerous cells, which can cause tumor metastasis and aggravate tumor progression. Besides, hypoxia plays a substantial role in tumor treatment, and it is one of the main reasons that malignant tumors are difficult to cure and have a poor prognosis. On account of the tumor specific hypoxic environment, many hypoxia-associative nanomedicine have been proposed for tumor treatment. Considering the enhanced targeting effect, designing hypoxia-associative nanomedicine can not only minimize the adverse effects of drugs on normal tissues, but also achieve targeted therapy at the lesion site. Mostly, there can be three strategies for the treatment of hypoxic tumor, including improvement of hypoxic environment, hypoxia responsive drug release and hypoxia activated prodrug. The review describes the design principle and applications of tumor hypoxia-associative nanomedicine in recent years, and also explores its development trends in solid tumor treatment. Moreover, this review presents the current limitations of tumor hypoxia-associative nanomedicine in chemotherapy, radiotherapy, photodynamic therapy, sonodynamic therapy and immunotherapy, which may provide a reference for clinic translation of tumor hypoxia-associative nanomedicine.