Intraoperative Identification of Liver Cancer Microfoci Using a Targeted Near-Infrared Fluorescent Probe for Imaging-Guided Surgery

Repurposing indocyanine green: exploring the potential of an old drug in modern medicine

The repurposing of existing drugs, referred to as theranostics, has made profound impacts on precision medicine. Indocyanine green (ICG), a well-established and clinical dye, has continued to be a star agent, described as a multifunctional molecule with concurrent photo- or sono-sensitiveness capabilities and co-delivery accessibility, showing remarkable potential in the area of unimodal or multimodal imaging-guided therapy of various diseases, leading to the extensive consideration of immediate clinical translations. In this review, we strive to bring the understanding of repurposing performance assessment for ICG into practice by clarifying the relationships between its features and applicability. Specifically, we address the obstacles encountered in the process of developing an ICG repurposing strategy, as well as the noteworthy advancements made in the field of ICG repurposing. We also go into detail about the structure-function correlations of drugs containing ICG and how different structural groups significantly affect the physicochemical properties.

Intraoperative Imaging in Hepatopancreatobiliary Surgery

Hepatopancreatobiliary surgery belongs to one of the most complex fields of general surgery. An intricate and vital anatomy is accompanied by difficult distinctions of tumors from fibrosis and inflammation; the identification of precise tumor margins; or small, even disappearing, lesions on currently available imaging. The routine implementation of ultrasound use shifted the possibilities in the operating room, yet more precision is necessary to achieve negative resection margins. Modalities utilizing fluorescent-compatible dyes have proven their role in hepatopancreatobiliary surgery, although this is not yet a routine practice, as there are many limitations. Modalities, such as photoacoustic imaging or 3D holograms, are emerging but are mostly limited to preclinical settings. There is a need to identify and develop an ideal contrast agent capable of differentiating between malignant and benign tissue and to report on the prognostic benefits of implemented intraoperative imaging in order to navigate clinical translation. This review focuses on existing and developing imaging modalities for intraoperative use, tailored to the needs of hepatopancreatobiliary cancers. We will also cover the application of these imaging techniques to theranostics to achieve combined diagnostic and therapeutic potential.

Proteinoid Polymers and Nanocapsules for Cancer Diagnostics, Therapy and Theranostics: In Vitro and In Vivo Studies

Proteinoids-simple polymers composed of amino acids-were suggested decades ago by Fox and coworkers to form spontaneously by heat. These special polymers may self-assemble in micrometer structures called proteinoid microspheres, presented as the protocells of life on earth. Interest in proteinoids increased in recent years, in particular for nano-biomedicine. They were produced by stepwise polymerization of 3-4 amino acids. Proteinoids based on the RGD motif were prepared for targeting tumors. Nanocapsules form by heating proteinoids in an aqueous solution and slowly cooling to room temperature. Proteinoid polymers and nanocapsules suit many biomedical applications owing to their non-toxicity, biocompatibility and immune safety. Drugs and/or imaging reagents for cancer diagnostic, therapeutic and theranostic applications were encapsulated by dissolving them in aqueous proteinoid solutions. Here, recent in vitro and in vivo studies are reviewed.

Near-infrared fluorescence imaging of hepatocellular carcinoma cells regulated by β-catenin signaling pathway

Background

Near-infrared fluorescence (NIRF) imaging has recently emerged as a promising tool for noninvasive cancer imaging. However, lack of tumor sensitivity and specificity restricts the application of NIRF dyes in surgical navigation.

Methods

Herein, we investigated the imaging features of NIRF dye MHI-148 and indocyanine green (ICG) in live cell imaging and xenograft nude mice models. TCGA dataset analysis and immunohistochemistry were conducted to investigate the expression of OATPs or ABCGs in hepatocellular carcinoma (HCC) tissues. OATPs or ABCGs were knocked down and overexpressed in HCC cells using transient transfection by siRNA and plasmids or stable transfection by lentivirus. Further, qRT-PCR ,Western blotting and the use of agonists or inhibitors targeting β-catenin signaling pathway were applied to explore its important role in regulation of OATP2B1 and ABCG2 expression.

Results

Here we demonstrated that NIRF dye MHI-148 was biocompatible as indocyanine green (ICG) but with higher imaging intensity and preferential uptake and retention in hepatocellular carcinoma (HCC) cells and tissues. Moreover, our data indicated that membrane transporters OATP2B1 and ABCG2, which regulated by β-catenin signaling pathway, mediated tumor-specific accumulation and retention of MHI-148 in HCC cells. In addition, the treatment with β-catenin inhibitor significantly enhanced the accumulation of MHI-148 in HCC tissues and improved the efficacy of tumor imaging with MHI-148 in vivo.

Conclusions

Our study uncovers a mechanism that links the distribution and expression of the membrane transporters OATP2B1 and ABCG2 to the tumor-specific accumulation of MHI-148, and provides evidence supporting a regulating role of the β-catenin signaling pathway in OATP2B1 and ABCG2- induced retention of MHI-148 inHCC tissues, and strategy targeting key components of MHI-148 transport machinery may be a potential approach to improve HCC imaging.

Optical imaging technology realizes early tumor diagnosis by detecting angiogenesis

The occurrence and development of blood vessels play a key role in different stages of tumor growth, while current imaging techniques are difficult to detect early tumor angiogenesis because of their low sensitivity. Therefore, this article introduces high-sensitivity optical imaging technology to achieve early tumor diagnosis by detecting tumor angiogenesis. Liver and pancreatic tumor models in nude mice were respectively established to represent tumors with a rich or poor blood supply. The two optical imaging methods, in vivo confocal fluorescence imaging and photoacoustic imaging, were used to detect tumor angiogenesis at different stages. Finally, the changes in blood vessels were verified by immunostaining. Both autoluminescence imaging and pathological staining confirmed that these two tumor models were successfully established. In vivo confocal fluorescence imaging found that the early tumor blood vessel structure had obvious characteristics: disorder, tortuous deformation, thin diameter, which were significantly different from the normal tissues. Photoacoustic imaging could effectively identify blood vessels inside early tumors, which were small and disordered and might be used as one of the predictors of early tumor development. CD31 immunostaining was used to evaluate the vascular status of tumors at different stages and under different blood supply conditions. The vascular structures observed under the microscope in the two tumor models were consistent with the results observed by optical imaging methods. The optical imaging methods could monitor the characteristics of angiogenesis in the rich or poor blood supply tumors, especially the early diagnosis of tumors.

Tumor-Targeting NIRF/MR Dual-Modal Molecular Imaging Probe for Surgery Navigation

Multimodality imaging recognized as a promising monitoring strategy can serve the needs of accurate diagnosis and treatment of cancer by providing molecular and anatomic information about tumor sites. However, the probes based on multiple imaging modalities for surgery navigation remain limited due to poor biocompatibility and tumor targeting specificity. Herein, we present a small-molecule near-infrared fluorescence/magnetic resonance (NIRF/MR) imaging probe, Gd-NMC-3, covalently coupled with DCDSTCY and Gd-DOTA via butane diamine, for precise detection and intraoperative visualization. The in vitro and in vivo studies demonstrated that Gd-NMC-3 could be effectively accumulated in tumor sites as a bimodal imaging molecule exhibiting significant fluorescence accumulation and reasonable relaxation property in tumors with low cytotoxicity and good biocompatibility. Furthermore, Gd-NMC-3 was successfully applied to provide real-time visual navigation in LM3 orthotopic and subcutaneous tumor models to guide the resection of tumors. Importantly, no more fluorescence was observed in mice after operation, implying the total removal of tumor tissues. In conclusion, Gd-NMC-3 has great potential to be applied in the clinic based on its high resolution and sensitivity in tumor imaging.

Multiplexed imaging in oncology

In oncology, technologies for clinical molecular imaging are used to diagnose patients, establish the efficacy of treatments and monitor the recurrence of disease. Multiplexed methods increase the number of disease-specific biomarkers that can be detected simultaneously, such as the overexpression of oncogenic proteins, aberrant metabolite uptake and anomalous blood perfusion. The quantitative localization of each biomarker could considerably increase the specificity and the accuracy of technologies for clinical molecular imaging to facilitate granular diagnoses, patient stratification and earlier assessments of the responses to administered therapeutics. In this Review, we discuss established techniques for multiplexed imaging and the most promising emerging multiplexing technologies applied to the imaging of isolated tissues and cells and to non-invasive whole-body imaging. We also highlight advances in radiology that have been made possible by multiplexed imaging.

The influence of Gd-DOTA ratios conjugating PLGA-PEG micelles encapsulated IR-1061 in bimodal over–1000 nm near–infrared fluorescence and magnetic resonance imaging

Multimodal imaging can provide multidimensional information for understanding concealed microstructures or bioprocesses in biological objects. The combination of over–1000 nm near–infrared (OTN–NIR) fluorescence imaging and magnetic resonance (MR) imaging is...

Near-infrared aggregation-induced emission nanodots for early diagnosis of tongue squamous cell carcinoma and sentinel lymph nodes mapping

Fluorescence imaging has been widely used in the biomedical field owing to its merits of high sensitivity, superb accuracy, high biosafety, etc. However, despite the well performance of fluorescent materials...

Mesoporous Silica Nanoparticle-Based Imaging Agents for Hepatocellular Carcinoma Detection

Hepatocellular carcinoma (HCC) is characterized by poor prognosis and high mortality. The treatment of HCC is closely related to the stage, and the early-stage of HCC patients usually accompanies a more long-term survival rate after clinical treatment. Hence, there are critical needs to develop effective imaging agents with superior diagnostic precision for HCC detection at an early stage. Recently, mesoporous silica nanoparticles (MSNs) based imaging agents have gained extensive attentions in HCC detection, which can serve as a multifunctional nanoplatform with controllable size and facile surface functionalization. This perspective summarizes recent advances in MSNs based imaging agents for HCC detection by the incorporation of several clinical imaging modalities. Multi-modal imaging system has been developed for higher spatial resolution and sensitivity. Even though some limitations and challenges need to be overcome, we envision the development of novel MSNs based imaging agents will offer great potential applications in clinical HCC detection.

Fluorescence imaging in the surgical management of liver cancers: Current status and future perspectives

Over the last decades, imaging technologies have got significant developments and become indispensable in the surgical management of liver cancers. Real-time navigation afforded by intraoperative images has a significant impact on the success of liver surgeries. Fluorescence imaging in the near-infrared spectrum has shown potential for tumor detection and image-guided surgery in clinics. While predominantly focused on indocyanine green (ICG) imaging, there is also accelerated development of more specific molecular tracers. Compared to passive targeting contrast agents ICG, active targeting and activatable probes both shed new light for intraoperative navigation owing to the higher degree of specificity for the tumor target. A variety of fluorescence imaging probes have been developed to target biomarkers unique to cancer cells or tumor microenvironment and demonstrated promising results. In this review, we provide a comprehensive update on preclinical development and clinical applications of fluorescence imaging in the surgical management of liver cancers. By highlighting the current status, we aim to offer insight into the challenges and opportunities for further investigation.

Emerging indocyanine green-integrated nanocarriers for multimodal cancer therapy: a review

Nanotechnology is a branch of science dealing with the development of new types of nanomaterials by several methods. In the biomedical field, nanotechnology is widely used in the form of nanotherapeutics. Therefore, the current biomedical research pays much attention to nanotechnology for the development of efficient cancer treatment. Indocyanine green (ICG) is a near-infrared tricarbocyanine dye approved by the Food and Drug Administration (FDA) for human clinical use. ICG is a biologically safe photosensitizer and it can kill tumor cells by producing singlet oxygen species and photothermal heat upon NIR irradiation. ICG has some limitations such as easy aggregation, rapid aqueous degradation, and a short half-life. To address these limitations, ICG is further formulated with nanoparticles. Therefore, ICG is integrated with organic nanomaterials (polymers, micelles, liposomes, dendrimers and protein), inorganic nanomaterials (magnetic, gold, mesoporous, calcium, and LDH based), and hybrid nanomaterials. The combination of ICG with nanomaterials provides highly efficient therapeutic effects. Nowadays, ICG is used for various biomedical applications, especially in cancer therapeutics. In this review, we mainly focus on ICG-based combined cancer nanotherapeutics for advanced cancer treatment.

Recent Progress of Near-Infrared Fluorescence in vivo Bioimaging in the Second and Third Biological Window

Near-infrared (NIR) fluorescence bioimaging using above to 1000 nm wavelength region is a promising analytical method on visualizing deep tissues. As compared to the short-wavelength ultraviolet (UV: < 400 nm) or visible (VIS: 400 - 700 nm) region, which results in an extremely low absorption or scattering of biomolecules and water in the body, NIR light passes through the tissues. Various fluorescent probes that emit NIR emission in the second (1100 - 1400 nm) or third (1550 - 1800 nm) biological windows have been developed and used for NIR in vivo imaging. Single-walled carbon nanotubes (SWCNTs), quantum dots (QDs), rare-earth doped ceramic nanoparticles (RED-CNPs), and organic dye-based probes have been proposed by many researchers, and are used to successfully visualize the bloodstream, organs, and disease-affected regions, such as cancer. NIR imaging in the second and third biological windows is an effective analytical method on visualizing deep tissues.

A path toward the clinical translation of nano-based imaging contrast agents

Recently, nanoparticles have evolved ubiquitously in therapeutic applications to treat a range of diseases. Despite their regular use as therapeutic agents in the clinic, we have yet to see much progress in their clinical translation as diagnostic imaging agents. Several clinical and preclinical studies support their use as imaging contrast agents, but their use in the clinical setting has been limited to off-label imaging procedures (i.e., Feraheme). Since diagnostic imaging has been historically used as an exploratory tool to rule out disease or to screen patients for various cancers, nanoparticle toxicity remains a concern, especially when introducing exogenous contrast agents into a potentially healthy patient population, perhaps rationalizing why several nano-based therapeutic agents have been clinically translated before nano-based imaging agents. Another potential hindrance toward their clinical translation could be their market potential, as most therapeutic drugs have higher earning potential than small-molecule imaging contrast agents. With these considerations in mind, perhaps a clinical path forward for nano-based imaging contrast agents is to help guide/manage therapy. Several studies have demonstrated the ability of nanoparticles to produce more accurate imaging preoperatively, intraoperatively, and postoperatively. These applications illustrate a more reliable method of cancer detection and treatment that can prevent incomplete tumor resection and incorrect assessment of tumor progression following treatment. The aim of this review is to highlight the research that supports the use of nanoparticles in biomedical imaging applications and offer a new perspective to illustrate how nano-based imaging agents have the potential to better inform therapeutic decisions. This article is categorized under: Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

A two-in-one Janus NIR-II AIEgen with balanced absorption and emission for image-guided precision surgery

Fluorescence imaging in the near-infrared II (NIR-II, 1000-1700 nm) region opens up new avenues for biological systems due to suppressed scattering and low autofluorescence at longer-wavelength photons. Nonetheless, the development of organic NIR-II fluorophores is still limited mainly due to the shortage of efficient molecular design strategy. Herein, we propose an approach of designing Janus NIR-II fluorophores by introducing electronic donors with distinct properties into one molecule. As a proof-of-concept, fluorescent dye 2 TT-m, oC6B with both twisted and planar electronic donors displayed balanced absorption and emission which were absent in its parent compound. The key design strategy for Janus molecule is that it combines the merits of intense absorption from planar architecture and high fluorescence quantum yield from twisted motif. The resulting 2 TT-m, oC6B nanoparticles exhibit a high molar absorptivity of 1.12 ⨯104 M-1 cm-1 at 808 nm and a NIR-II quantum yield of 3.7%, displaying a typical aggregation-induced emission (AIE) attribute. The highly bright and stable 2 TT-m, oC6B nanoparticles assured NIR-II image-guided cancer surgery to resect submillimeter tumor nodules. The present study may inspire further development of molecular design philosophy for highly bright NIR-II fluorophores for biomedical applications.

Application of Near-Infrared Fluorescence Imaging Technology in Liver Cancer Surgery

Background. Hepatocellular carcinoma, among the most common malignant digestive system tumorsworldwide, is most effectively treated with precise surgical resection. Near-infrared fluorescence imaging technology is being increasingly used clinically and has achieved great initial results in the navigation of liver cancer surgery. Methods. This review describes the application of indocyanine green fluorescence (ICG) imaging technology with near-infrared window I in the navigation of liver cancer surgery, explores novel fluorescent probes and near-infrared window II fluorescence imaging technology, and discusses the development status of the 2 emerging tools. Results. ICG fluorescence imaging technology can precisely localize the tumor, reveal the boundary of liver cancer or liver segment, and identify the bile leakage. The novel fluorescent probe is more targeted than ICG, which makes the detection of cancer more accurate. Near-infrared window II fluorescence imaging technology can lead to outstanding gains in deeper detection, higher resolution, and fidelity. But, due to the shortcomings of machine and probe, it is not widely used in clinical. Conclusion. Near-infrared fluorescence imaging has great development potential. With the advent of precision medicine and the progress of various biotechnology studies, fluorescence imaging technology will be better developed and applied in the diagnosis, surgical navigation, and treatment of liver cancer.

Synthesis of fluorescent nanoprobe with simultaneous response to intracellular pH and Zn2+ for tumor cell distinguishment

A novel dual-functional nanoprobe was designed and synthesized by facile assembly of quinoline derivative (PEIQ) and meso-tetra (4-carboxyphenyl) porphine (TCPP) via electrostatic interaction for simultaneous sensing of fluorescence of Zn²⁺ and pH. Under the single-wavelength excitation at 400 nm, this nanoprobe not only exhibits "OFF-ON" green fluorescence at 512 nm by specific PEIQ-Zn²⁺ chelation, but also presents red fluorescence enhancement at 654 nm by H⁺-triggered TCPP release. The nanoprobe demonstrated excellent sensing performance with a good linear range (Zn²⁺, 1-40 μM; pH, 5.0-8.0), low detection limit (Zn²⁺, 0.88 μM), and simultaneous response towards Zn²⁺ and pH in pure aqueous solution within 2 min. More importantly, this dual-functional nanoprobe demonstrates the capability of discerning cancerous cells from normal cells, as evidenced by the fact that cancerous HepG2 cells in tumor microenvironment exhibit substantially higher red fluorescence and significantly lower green fluorescence than normal HL-7702 cells. The simultaneous, real-time fluorescence imaging of multiple analytes in a living system could be significant for cell analysis and tracking, cancer diagnosis, and even fluorescence-guided surgery of tumors.

A narrative review of near-infrared fluorescence imaging in hepatectomy for hepatocellular carcinoma

Hepatectomy is a main therapeutic strategy for hepatocellular carcinoma (HCC), which requires removal of primary and disseminated tumors and maximum preservation of normal liver tissue. However, in a clinical operation, it is difficult to recognize the tumor tissue and its boundary with the naked eye and palpation, which often leads to insufficient or excessive resection. Near-infrared fluorescence (NIRF) imaging, a non-invasive, real-time, low-cost, and highly sensitive imaging technique has been extensively studied in surgical navigation. With the development of fluorescence imaging system and fluorescent probe, intraoperative tumor detection and margin definition can be achieved, making the operation more accurate. Advances in fluorescence imaging of HCC in the NIR region have focused on the traditional first NIR window (NIR-I, 700–900 nm), and have recently been extended to the second NIR window (NIR-II, 1,000–1,700 nm). Compared with NIR-I imaging, fluorescence imaging in the NIR-II exhibits great advantages, including higher spatial resolution, deeper penetration depth, and lower optical absorption and scattering from biological substrates with minimal tissue autofluorescence. There is no doubt that developing novel NIRF probes for in vivo imaging of HCC has high significance and direct impact on the field of liver surgery. In this article, the development of various NIRF probes for fluorescence image guided HCC hepatectomy is reviewed, and current challenges and potential opportunities of these imaging probes are discussed.

Surface modified NIR magnetic nanoprobes for theranostic applications

Objectives: Near-Infrared based imaging modalities integrated with thermotherapy can facilitate detection of cancer at early stages and mediate high-resolution image-guided hyperthermia. In this work, fluorescent iron oxide nanoparticles (FIO) have been developed possessing deep tissue penetrable NIR imaging and site-specific magnetic hyperthermia characteristics for the elimination of cancer cells.Methods: One-pot synthesis of amine-functionalized superparamagnetic iron oxide nanoparticles (HIO) were achieved using ethylenediamine (EDA) facilitated conjugation of indocyanine green (ICG) mediated by electrostatic interactions.Results: EDA acts as a capping and reducing agent to direct the structural growth of hydrophilic Fe₃O₄ nanocrystals with high saturation magnetization, specific absorption rate, and T₂ value of 118 emu/g, 329.8 ± 5.96 W/g, and 40.17 mM^-1s^-1, respectively. Here, Fe²⁺/Fe³⁺ of two was maintained to achieve magnetite nanocrystals contradictory to the gold standard ratio of 0.5 without additives for nucleation and growth. Developed FIO showed excellent cytocompatibility even at higher concentrations and on subjecting to magnetic hyperthermia reduced its survival percentage. FIO biodistribution in mice showed enhanced half-life than free ICG with preferential localization in the brain and liver.Conclusion: Developed FIO using a facile technique is a potential clinical alternative for cellular tracking, imaging, and hyperthermia.

Conjugated Photosensitizers for Imaging and PDT in Cancer Research

Early cancer detection and perfect understanding of the disease are imperative toward efficient treatments. It is straightforward that, for choosing a specific cancer treatment methodology, diagnostic agents undertake a critical role. Imaging is an extremely intriguing tool since it assumes a follow up to treatments to survey the accomplishment of the treatment and to recognize any conceivable repeating injuries. It also permits analysis of the disease, as well as to pursue treatment and monitor the possible changes that happen on the tumor. Likewise, it allows screening the adequacy of treatment and visualizing the state of the tumor. Additionally, when the treatment is finished, observing the patient is imperative to evaluate the treatment methodology and adjust the treatment if necessary. The goal of this review is to present an overview of conjugated photosensitizers for imaging and therapy.

Synthesis and Characterization of Poly(RGD) Proteinoid Polymers and NIR Fluorescent Nanoparticles of Optimal d,l-Configuration for Drug-Delivery Applications-In Vitro Study

RGD sequence is a tripeptide composed of three amino acids: arginine (R), glycine (G), and aspartic acid (D). The RGD peptide has a high affinity to the integrin alpha v beta 3, which is overexpressed on the membrane of many cancer cells and is attracted to areas of angiogenesis. Proteinoids are biodegradable polymers based on amino acids which are formed by bulk thermal step-growth polymerization mechanism. Hollow proteinoid nanoparticles (NPs) may be formed via self-assembly process of the proteinoid polymers. We propose using novel RGD-based proteinoid polymers to manufacture NPs in which the RGD motif is self-incorporated in the proteinoid backbone. Such P(RGD) NPs can act both as a drug carrier (by encapsulation of a desired drug) and as a targeting delivery system. This article presents the synthesis of four RGD proteinoids with different RGD optical configurations, (d) or (l) arginine, glycine, and (d) or (l) aspartic acid, in order to determine which configuration is optimal as a drug-targeting carrier. These new RGD proteinoid polymers possess high molecular weights and molecular weight monodispersity. Homonuclear nuclear magnetic resonance methods were employed to predict the expected concentration of RGD tripeptide sequence in the polymer. Near infrared fluorescent NPs have been prepared by the encapsulation of indocyanine green (ICG) dye within the different P(RGD) NPs. The dry diameters of the hollow P(R^dGD^d), P(R^dGD), P(RGD), and P(RGD^d) NPs are 55 ± 13, 48 ± 9, 45 ± 11, and 42 ± 9 nm, respectively, whereas those of the ICG-encapsulated NPs were significantly higher, 141 ± 24, 95 ± 13, 86 ± 11, and 87 ± 12 nm, respectively. The ICG-encapsulated P(R^dGD) NPs exhibited higher selectivity toward epithelial injury, as demonstrated using an in vitro scratch assay, because the P(R^dGD) NPs accumulated in the injured area at higher concentrations when compared to other P(RGD) NPs with different chiralities. Therefore, the P(R^dGD) polymer configuration is the polymer of choice for use as a targeted drug carrier to areas of angiogenesis, such as in tumors, wounds, or cuts.

Evaluation of electrical properties of ex vivo human hepatic tissue with metastatic colorectal cancer

OBJECTIVE

To probe the distribution of electrical properties in tumor-bearing human hepatic tissues with metastatic colorectal cancer.

APPROACH

Electrochemical impedance spectroscopy (EIS) and a non-contact electromagnetic probe were used for distinguishing spatial heterogeneities in fresh, unfixed human hepatic tissues ex vivo from patients with metastatic colorectal cancer (CRC).

MAIN RESULTS

Point-wise EIS measurements reported over a frequency range of 100 Hz-1 MHz showed that the interface tissue between visible tumor and normal tissue exhibits an electrically different domain (p < 0.05) from both normal tissue (over 100 Hz-100 kHz) and tumor tissue (over 100 Hz-1 MHz). Observations of the microstructure on tumor-bearing hepatic tissue from hematoxylin and eosin stained images and the equivalent circuit modelling were used to validate the impedance measurements and characterize previously unidentified interfacial domain between normal and tumor tissue. Lastly, in a proof of concept study, a new in-house designed non-contact electromagnetic probe, as opposed to the invasive EIS measurements, was demonstrated for distinguishing tumor tissue from the normal tissue in a hepatic tissue specimen from a patient with metastatic CRC.

SIGNIFICANCE

EIS measurements, correlated with histological observations, show potential for mapping electrical properties in tumor-bearing human hepatic tissue.

Update on the development of molecular imaging and nanomedicine in China: Optical imaging

Molecular imaging has received increased attention worldwide, including in China, because it offers noninvasive characterization of widely diverse clinically significant pathologies. To achieve these goals, nanomedicine has evolved into a broad interdisciplinary field with flexible designs to accommodate and concentrate imaging and therapeutic payloads into pathological cells through selective binding to disease specific cell membrane biomarkers. This concept of personalized medicine reflects the vision of "magic bullets" proposed by German biochemist Paul Ehrlich over 100 years ago. As happening worldwide, Chinese scientists are contributing to this tsunami of science and technologies through impactful national programs and international research collaborations. This review provides a comprehensive update of Chinese innovations to address intractable unmet medical need in China and worldwide in the optical sciences. This article is categorized under: Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Image-guided tumor surgery: The emerging role of nanotechnology

Surgical resection is a mainstay treatment for solid tumors. Yet, methods to distinguish malignant from healthy tissue are primarily limited to tactile and visual cues as well as the surgeon's experience. As a result, there is a possibility that a positive surgical margin (PSM) or the presence of residual tumor left behind after resection may occur. It is well-documented that PSMs can negatively impact treatment outcomes and survival, as well as pose an economic burden. Therefore, surgical tumor imaging techniques have emerged as a promising method to decrease PSM rates. Nanoparticles (NPs) have unique characteristics to serve as optical contrast agents during image-guided surgery (IGS). Recently, there has been tremendous growth in the volume and types of NPs used for IGS, including clinical trials. Herein, we describe the most recent contributions of nanotechnology for surgical tumor identification. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Implantable Materials and Surgical Technologies > Nanoscale Tools and Techniques in Surgery Diagnostic Tools > in vivo Nanodiagnostics and Imaging.

Emerging and Innovative Theranostic Approaches for Mesoporous Silica Nanoparticles in Hepatocellular Carcinoma: Current Status and Advances

Hepatocellular carcinoma (HCC) is one of the most prevalent and lethal solid cancers globally. To improve diagnosis sensitivities and treatment efficacies, the development of new theranostic nanoplatforms for efficient HCC management is urgently needed. In the past decade, mesoporous silica nanoparticles (MSNs) with tailored structure, large surface area, high agents loading volume, abundant chemistry functionality, acceptable biocompatibility have received more and more attention in HCC theranostic. This review outlines the recent advances in MSNs-based systems for HCC therapy and diagnosis. The multifunctional hybrid nanostructures that have both of therapy and diagnosis abilities are highlighted. And the precision delivery strategies of MSNs in HCC are also discussed. Final, we conclude with our personal perspectives on the future development and challenges of MSNs.

Recent progress in biomedical applications of RGD-based ligand: From precise cancer theranostics to biomaterial engineering: A systematic review

Arginine-glycine-aspartic acid (RGD) peptide family is known as the most prominent ligand for extracellular domain of integrin receptors. Specific expression of these receptors in various tissue of human body and tight association of their expression profile with various pathophysiological conditions made these receptors a suitable targeting candidate for several disease diagnosis and treatment as well as regeneration of various organs. For these reasons, various forms of RGD-based integrins ligands have been greatly used in biomedical studies. Here, we summarized the last decade application progress of RGD for cancer theranostics, control of inflammation, thrombosis inhibition and critically discussed the effect of RGD peptides structure and sequence on the efficacy of gene/drug delivery systems in preclinical studies. Furthermore, we will show recent advances in application of RGD functionalized biomaterials for various tissue regenerations including cornea repair, artificial neovascularization and bone tissue regeneration. Finally, we analyzed clinically translatability of RGD peptides, considering examples of integrin ligands in clinical trials. In conclusion, prospects on using RGD peptide for precise drug delivery and biomaterial engineering are well discussed.

Theragnostic potentials of core/shell mesoporous silica nanostructures

Theragnostics is considered as an emerging treatment strategy that integrates therapeutics and diagnostics thus allowing delivery of therapeutics and simultaneous monitoring of the progression of treatment. Among the different types of inorganic nanomaterials that are being used for nanomedicine, core shell mesoporous silica nanoparticles have emerged as promising multifunctional nanoplatform for theragnostic application. Research in the design of core/shell mesoporous silica nanoparticles is steadily diversifying owing to the various interesting properties of these nanomaterials that are advantageous for advanced biomedical applications. Core/shell mesoporous silica nanoparticles, have garnered substantial attention in recent years because of their exceptional properties including large surface area, low density, ease of functionalization, high loading capacity of drugs, control of the morphology, particle size, tunable hollow interior space and mesoporous shell and possibility of incorporating multifunctional interior core material. In the past decade researcher's demonstrated tremendous development in design of functionalized core/shell mesoporous silica nanoparticles with different inorganic functional nanomaterial incorporated into mesoporous nanosystem for simultaneous therapeutic and diagnostic (theragnostic) applications in cancer. In this review, we recapitulate the progress in commonly used synthetic strategies and theragnostic applications of core/shell mesoporous silica nanoparticles with special emphasis on therapeutic and diagnostic modalities. Finally, we discuss the challenges and some perspectives on the future research and development of theragnostic core/shell mesoporous silica nanoparticles.

Innovative treatment for hepatocellular carcinoma (HCC)

Indocyanine green (ICG) is not new in the field of liver surgery. Early studies performed in the 1980s and 1990s revealed the value of the ICG clearance test in predicting post-hepatectomy morbidity and mortality. ICG clearance and retention tests are crucial for determining precise liver function before liver surgery and offer several benefits for safe surgery. Whereas ICG is well-known and has long history in medicine, recent progress in infrared light technology over the last decade has highlighted another feature of ICG. For example, ICG fluorescence-guided surgery may change the next generation of liver surgery. In the near future, ICG with near-infrared (NIR) light photodynamic therapy (PDT) is expected to become a new treatment method for hepatocellular carcinoma (HCC). Furthermore, several aspects of the mechanisms of ICG accumulation in HCC cells have been revealed by important basic research studies. New imaging technologies and mechanistic findings keep ICG in the spotlight. In this article, we review three recently described topics of ICG which may contribute to the development of innovative and new treatments method for HCC, fluorescence-guided surgery, mechanism of ICG accumulation in HCC cells, PDT for HCC.

NIR-II nanoprobes in-vivo assembly to improve image-guided surgery for metastatic ovarian cancer

Local recurrence is a common cause of treatment failure for patients with solid tumors. Tumor-specific intraoperative fluorescence imaging may improve staging and debulking efforts in cytoreductive surgery and, thereby improve prognosis. Here, we report in vivo assembly of the second near-infrared window (NIR-II) emitting downconversion nanoparticles (DCNPs) modified with DNA and targeting peptides to improve the image-guided surgery for metastatic ovarian cancer. The NIR-II imaging quality with DCNPs is superior to that of clinically approved ICG with good photostability and deep tissue penetration (8 mm). Stable tumor retention period experienced 6 h by in vivo assembly of nanoprobes can be used for precise tumor resection. Superior tumor-to-normal tissue ratio is successfully achieved to facilitate the abdominal ovarian metastases surgical delineation. Metastases with ≤1 mm can be completely excised under NIR-II bioimaging guidance. This novel technology provides a general new basis for the future design of nanomaterials for medical applications.

Corannulene-Incorporated AIE Nanodots with Highly Suppressed Nonradiative Decay for Boosted Cancer Phototheranostics In Vivo

Fluorescent nanoparticles (NPs) based on luminogens with aggregation-induced emission characteristic (AIEgens), namely AIE dots, have received wide attention because of their antiquenching attitude in emission and reactive oxygen species (ROS) generation when aggregated. However, few reports are available on how to control and optimize their fluorescence and ROS generation ability. Herein, it is reported that enhancing the intraparticle confined microenvironment is an effective approach to advanced AIE dots, permitting boosted cancer phototheranostics in vivo. Formulation of a "rotor-rich" and inherently charged near-infrared (NIR) AIEgen with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene glycol)-2000] and corannulene-decorated PEG affords DSPE-AIE dots and Cor-AIE dots, respectively. Compared to DSPE-AIE dots, Cor-AIE dots show 4.0-fold amplified fluorescence quantum yield and 5.4-fold enhanced ROS production, because corannulene provides intraparticle rigidity and strong interactions with the AIEgen to restrict the intramolecular rotation of AIEgen to strongly suppress the nonradiative decay and significantly facilitate the fluorescence pathway and intersystem crossing. Thus, it tremendously promotes phototheranostic efficacies in terms of NIR image-guided cancer surgery and photodynamic therapy using a peritoneal carcinomatosis-bearing mouse model. Collectively, it not only provides a novel strategy to advanced AIE dots for cancer phototheranostics, but also brings new insights into the design of superior fluorescent NPs for biomedical applications.

Differentiation-inducing therapeutic effect of Notch inhibition in reversing malignant transformation of liver normal stem cells via MET

BACKGROUND

Liver cancer stem cells (LCSCs) are the key factors for cancer metastasis, recurrent, and drug resistance. LCSCs are originated from either hepatocytes dedifferentiation or differentiation arresting of liver normal stem cells (LNSCs). Differentiation-inducing therapy is a novel strategy in solid tumors. Furthermore, Notch signaling pathway has been proved to play important role in the process of hepatocytes differentiation. In previous study, a malignant transformation cellular model of LNSCs has been built up, and in this study we are trying to illustrate whether inhibition of Notch can reverse this malignant tendency and drive these malignant cells back to differentiate into mature hepatocytes.

RESULTS

Inhibition of Notch signaling pathway can down-regulate the stemness-related cancer markers, lower the proliferative status, alleviate the invasive characteristic, or attenuate the metastasis tendency. What is more, it can help the malignantly transformed cells to regain the mature hepatic function of glucagon synthesis, urea metabolism, albumin production, and indocyanine-green (ICG) clearance.

MATERIALS AND METHODS

HOX transcript antisense RNA (HOTAIR) expression was enhanced in LNSCs via lentivirus transduction to set up the malignant transformation cellular model. Then, a Notch inhibitor was applied to induce malignantly transformed cells differentiate into mature hepatocytes, and malignant abilities of proliferation, invasiveness, tumorigenesis as well as mature hepatocyte function were observed and compared.

CONCLUSIONS

The data demonstrate that the anti-tumor effects of Notch inhibition may lie not only on killing the cancer cells or LCSCs directly, it can also induce the LCSCs differentiation into mature hepatocytes via mesenchymal-epithelial transition (MET) progress or downgrade the malignancy.

Recent advances in near-infrared light-responsive nanocarriers for cancer therapy

In recent years, research has focused on the development of smart nanocarriers that can respond to specific stimuli. Among the various stimuli-responsive platforms for cancer therapy, near-infrared (NIR) light (700-1000nm)-responsive nanocarriers have gained considerable interest because of their deeper tissue penetration capacity, precisely controlled drug release, and minimal damage towards normal tissues. In this review, we outline various therapeutic applications of NIR-responsive nanocarriers in drug delivery, photothermal therapy (PTT), photodynamic therapy (PDT), and bioimaging. We also highlight recent trends towards NIR-responsive combinatorial therapy and multistimuli-responsive nanocarriers for improving therapeutic outcomes.

Near infrared-emitting persistent luminescent nanoparticles for Hepatocellular Carcinoma imaging and luminescence-guided surgery

Hepatocellular carcinoma (HCC), the fifth most common cancer worldwide, is increasing nowadays and poses a serious threat to human health. However, if treated effectively and timely, it is clinically manageable or curable. Therefore, accurate detection and complete surgical resection remain priorities for HCC with a high potential of improving both survival and quality of life. Lacking of real-time guide technology, traditional surgery are usually relied on the subjective experience of surgeon, which have the limitation of high sensitivity detection tumor. Here, we developed a contrast agent, ZnGa₂O₄Cr_0.004 (ZGC), used for guided surgery during operation to accurate delineation of HCC. ZGC showed excellent long-lasting afterglow properties that lasted for hours, which can aid in real-time guided surgery. Meanwhile, ZGC display high spatial resolution and deep penetration during pre-operation for diagnostic computed tomography (CT). Interestingly, we observed reverse imaging in the tumor region, known as a "dark hole", which further improves the contrast for surgery. This new multi-modality nanoparticle has great potential for accurate liver cancer imaging and resection guidance.

Indocyanine green-incorporating nanoparticles for cancer theranostics

Indocyanine green (ICG) is a near-infrared dye that has been used in the clinic for retinal angiography, and defining cardiovascular and liver function for over 50 years. Recently, there has been an increasing interest in the incorporation of ICG into nanoparticles (NPs) for cancer theranostic applications. Various types of ICG-incorporated NPs have been developed and strategically functionalised to embrace multiple imaging and therapeutic techniques for cancer diagnosis and treatment. This review systematically summaries the biodistribution of various types of ICG-incorporated NPs for the first time, and discusses the principles, opportunities, limitations, and application of ICG-incorporated NPs for cancer theranostics. We believe that ICG-incorporated NPs would be a promising multifunctional theranostic platform in oncology and facilitate significant advancements in this research-active area.

New horizons in multimodality molecular imaging and novel radiotracers

Positron emission tomography (PET)/computerised tomography is now established in clinical practice for oncologic and non-oncological applications. Improvement and development of scanner hardware has allowed faster acquisitions and wider application. PET/magnetic resonance imaging offers potential improvements in diagnostic accuracy and patient acceptability but clinical applications are still being developed. A range of new radiotracers and non-radioactive contrast agents is likely to lead to a growth in hybrid molecular imaging applications that will allow better characterisation of disease processes.

Modulating angiogenesis with integrin-targeted nanomedicines

Targeting angiogenesis-related pathologies, which include tumorigenesis and metastatic processes, has become an attractive strategy for the development of efficient guided nanomedicines. In this respect, integrins are cell-adhesion molecules involved in angiogenesis signaling pathways and are overexpressed in many angiogenic processes. Therefore, they represent specific biomarkers not only to monitor disease progression but also to rationally design targeted nanomedicines. Arginine-glycine-aspartic (RGD) containing peptides that bind to specific integrins have been widely utilized to provide ligand-mediated targeting capabilities to small molecules, peptides, proteins, and antibodies, as well as to drug/imaging agent-containing nanomedicines, with the final aim of maximizing their therapeutic index. Within this review, we aim to cover recent and relevant examples of different integrin-assisted nanosystems including polymeric nanoconstructs, liposomes, and inorganic nanoparticles applied in drug/gene therapy as well as imaging and theranostics. We will also critically address the overall benefits of integrin-targeting.

Long wavelength excitable near-infrared fluorescent nanoparticles with aggregation-induced emission characteristics for image-guided tumor resection

Near infrared (NIR) fluorescence imaging (700-900 nm) is a promising technology in preclinical and clinical tumor diagnosis and therapy. The availability of excellent NIR fluorescent contrast agents is still the main barrier to implementing this technology. Herein, we report the design and synthesis of two series of NIR fluorescent molecules with long wavelength excitation and aggregation-induced emission (AIE) characteristics by fine-tuning their molecular structures and substituents. Further self-assembly between an amphiphilic block co-polymer and the obtained AIE molecules leads to AIE nanoparticles (AIE NPs), which have absorption maxima at 635 nm and emission maxima between 800 and 815 nm with quantum yields of up to 4.8% in aggregated states. In vitro and in vivo toxicity results demonstrate that the synthesized AIE NPs are biocompatible. Finally, the synthesized AIE NPs have been successfully used for image-guided tumor resection with a high tumor-to-normal tissue signal ratio of 7.2.

Highly Specific and Sensitive Fluorescent Nanoprobes for Image-Guided Resection of Sub-Millimeter Peritoneal Tumors

A current challenge in the treatment of peritoneal carcinomatosis is the inability to detect, visualize, and resect small or microscopic tumors of pancreatic, ovarian, or mesothelial origin. In these diseases, the completeness of primary tumor resection is directly correlated with patient survival, and hence, identifying small sub-millimeter tumors (i.e., disseminated disease) is critical. Thus, new imaging techniques and probes are needed to improve cytoreductive surgery and patient outcomes. Highly fluorescent rhodamine-labeled expansile nanoparticles (HFR-eNPs) are described for use as a visual aid during cytoreductive surgery of pancreatic carcinomatosis. The covalent incorporation of rhodamine into ∼30 nm eNPs increases the fluorescent signal compared to free rhodamine, thereby affording a brighter and more effective probe than would be achieved by a single rhodamine molecule. Using the intraperitoneal route of administration, HFR-eNPs localize to regions of large (∼1 cm), sub-centimeter, and sub-millimeter intraperitoneal tumor in three different animal models, including pancreatic, mesothelioma, and ovarian carcinoma. Tumoral localization of the HFR-eNPs depends on both the material property (i.e., eNP polymer) as well as the surface chemistry (anionic surfactant vs PEGylated noncharged surfactant). In a rat model of pancreatic carcinomatosis, HFR-eNP identification of tumor is validated against gold-standard histopathological analysis to reveal that HFR-eNPs possess high specificity (99%) and sensitivity (92%) for tumors, in particular, sub-centimeter and microscopic sub-millimeter tumors, with an overall accuracy of 95%. Finally, as a proof-of-concept, HFR-eNPs are used to guide the resection of pancreatic tumors in a rat model of peritoneal carcinomatosis.

Combination of Fluorescence-Guided Surgery With Photodynamic Therapy for the Treatment of Cancer

Specific visualization of body parts is needed during surgery. Fluorescence-guided surgery (FGS) uses a fluorescence contrast agent for in vivo tumor imaging to detect and identify both malignant and normal tissues. There are several advantages and clinical benefits of FGS over other conventional medical imaging modalities, such as its safety, effectiveness, and suitability for real-time imaging in the operating room. Recent advancements in contrast agents and intraoperative fluorescence imaging devices have led to a greater potential for intraoperative fluorescence imaging in clinical applications. Photodynamic therapy (PDT) is an alternative modality to treat tumors, which uses a light-sensitive drug (photosensitizers) and special light to destroy the targeted tissues. In this review, we discuss the fluorescent contrast agents, some newly developed imaging devices, and the successful clinical application of FGS. Additionally, we present the combined strategy of FGS with PDT to further improve the therapeutic effect for patients with cancer. Taken together, this review provides a unique perspective and summarization of FGS.

Cancer Diagnosis and Imaging-Guided Photothermal Therapy Using a Dual-Modality Nanoparticle

To improve patient outcome and decrease overall health-care costs, highly sensitive and precise detection of a tumor is required for its accurate diagnosis and efficient therapy; however, this remains a challenge when using conventional single mode imaging. Here, we successfully designed a near-infrared (NIR)-response photothermal therapy (PTT) platform (Au@MSNs-ICG) for the location, diagnosis, and NIR/computer tomography (CT) bimodal imaging-guided PTT of tumor tissues, using gold (Au) nanospheres coated with indocyanine green (ICG)-loaded mesoporous silica nanoparticles (MSNs), which would have high sensitivity and precision. The nanoparticles (NPs) exhibited good monodispersity, fluorescence stability, biocompatibility, and NIR/CT signaling and had a preferable temperature response under NIR laser irradiation in vitro or in vivo. Using a combination of NIR/CT imaging and PTT treatment, the tumor could be accurately positioned and thoroughly eradicated in vivo by Au@MSNs-ICG injection. Hence, the multifunctional NPs could play an important role in facilitating the accurate treatment of tumors in future clinical applications.