Folic acid-functionalized gadolinium-loaded phase transition nanodroplets for dual-modal ultrasound/magnetic resonance imaging of hepatocellular carcinoma

Application of rare earth elements in dual-modality molecular probes

The unique 4f subshell electronic structure of rare earth elements endows them with exceptional properties in electrical, magnetic, and optical domains. These properties include prolonged fluorescence lifetimes, large Stokes shifts, distinctive spectral bands, and strong resistance to photobleaching, making them ideal for the synthesis of molecular probes. Each imaging technique possesses unique advantages and specific applicabilities but also inherent limitations due to its operational principles. Dual-modality molecular probes effectively address these limitations, particularly in applications involving high-resolution Magnetic Resonance Imaging (MRI) such as MRI/OI, MRI/PET, MRI/CT, and MRI/US. This review summarizes the applications, advantages, challenges, and current research status of rare earth elements in these four dual imaging modalities, providing a theoretical basis for the future development and application of rare earth elements in the field of dual-modality molecular probes.

Heteroatom-doped magneto-fluorescent carbon dots, a potent agent for multimodal imaging

A simple, one-pot and green method is reported for hydrothermal synthesis of highly fluorescent and magnetic carbon dots (CDs) by using D-glucose, as the carbon source. CDs were fully characterized by the UV-Vis and fluorescence spectroscopy, DLS, FTIR, TEM, EDS, XRD, and VSM. The nitrogen doping of different diamines significantly improved the fluorescence quantum yield (QY) of CDs with the maximum effect obtained by using m-phenylenediamine (mPDA). Temperature and reaction time also affected the QY of CDs with the best results obtained at 150 °C for 3 h. The heteroatom doping by innovative use of different metal sulfates including FeSO4, MnSO4, CuSO4, MgSO4, and ZnSO4, further improved the optical properties of CDs. Interestingly, the magnetic and multicolor CDs with high colloidal stability and QYs of 17.7, 16.5, and 53.9% at 460, 490, and 515 nm, respectively, were synthesized by using 0.1 M of glucose, mPDA and MnSO4. The resulted Mn-, S-, N-doped CDs represented rapid uptake and high-quality fluorescence imaging of the human fibroblast and umbilical vein endothelial cells in vitro, without significant toxicity. The CDs also displayed high r1 relaxivity of 32.3 mM- 1 s- 1 and were used for high-contrast MR and fluorescence imaging of mouse tumor models, in vivo.

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.

Charged Gold Nanoparticles for Target Identification-Alignment and Automatic Segmentation of CT Image-Guided Adaptive Radiotherapy in Small Hepatocellular Carcinoma

Because of the challenges posed by anatomical uncertainties and the low resolution of plain computed tomography (CT) scans, implementing adaptive radiotherapy (ART) for small hepatocellular carcinoma (sHCC) using artificial intelligence (AI) faces obstacles in tumor identification-alignment and automatic segmentation. The current study aims to improve sHCC imaging for ART using a gold nanoparticle (Au NP)-based CT contrast agent to enhance AI-driven automated image processing. The synthesized charged Au NPs demonstrated notable in vitro aggregation, low cytotoxicity, and minimal organ toxicity. Over time, an in situ sHCC mouse model was established for in vivo CT imaging at multiple time points. The enhanced CT images processed using 3D U-Net and 3D Trans U-Net AI models demonstrated high geometric and dosimetric accuracy. Therefore, charged Au NPs enable accurate and automatic sHCC segmentation in CT images using classical AI models, potentially addressing the technical challenges related to tumor identification, alignment, and automatic segmentation in CT-guided online ART.

Application and prospects of AI-based radiomics in ultrasound diagnosis

Artificial intelligence (AI)-based radiomics has attracted considerable research attention in the field of medical imaging, including ultrasound diagnosis. Ultrasound imaging has unique advantages such as high temporal resolution, low cost, and no radiation exposure. This renders it a preferred imaging modality for several clinical scenarios. This review includes a detailed introduction to imaging modalities, including Brightness-mode ultrasound, color Doppler flow imaging, ultrasound elastography, contrast-enhanced ultrasound, and multi-modal fusion analysis. It provides an overview of the current status and prospects of AI-based radiomics in ultrasound diagnosis, highlighting the application of AI-based radiomics to static ultrasound images, dynamic ultrasound videos, and multi-modal ultrasound fusion analysis.

Application of Nanoparticles in the Diagnosis of Gastrointestinal Diseases: A Complete Future Perspective

The diagnosis of gastrointestinal (GI) diseases currently relies primarily on invasive procedures like digestive endoscopy. However, these procedures can cause discomfort, respiratory issues, and bacterial infections in patients, both during and after the examination. In recent years, nanomedicine has emerged as a promising field, providing significant advancements in diagnostic techniques. Nanoprobes, in particular, offer distinct advantages, such as high specificity and sensitivity in detecting GI diseases. Integration of nanoprobes with advanced imaging techniques, such as nuclear magnetic resonance, optical fluorescence imaging, tomography, and optical correlation tomography, has significantly enhanced the detection capabilities for GI tumors and inflammatory bowel disease (IBD). This synergy enables early diagnosis and precise staging of GI disorders. Among the nanoparticles investigated for clinical applications, superparamagnetic iron oxide, quantum dots, single carbon nanotubes, and nanocages have emerged as extensively studied and utilized agents. This review aimed to provide insights into the potential applications of nanoparticles in modern imaging techniques, with a specific focus on their role in facilitating early and specific diagnosis of a range of GI disorders, including IBD and colorectal cancer (CRC). Additionally, we discussed the challenges associated with the implementation of nanotechnology-based GI diagnostics and explored future prospects for translation in this promising field.

Delivery of melarsoprol using folate-targeted PEGylated cyclodextrin-based nanoparticles for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer, and has become one of the most lethal malignancies in the world. Although chemotherapy remains a cornerstone of cancer therapy, the number of chemotherapeutic drugs approved for HCC is low, and emerging therapeutics are needed. Melarsoprol (MEL) is an arsenic-containing drug, and has been applied in the treatment of human African trypanosomiasis at the late stage. In this study, the potential of MEL for HCC therapy was investigated for the first time using in vitro and in vivo experimental approaches. A folate-targeted polyethylene glycol-modified amphiphilic cyclodextrin nanoparticle was developed for safe, efficient and specific delivery of MEL. Consequently, the targeted nanoformulation achieved cell-specific uptake, cytotoxicity, apoptosis and migration inhibition in HCC cells. Furthermore, the targeted nanoformulation significantly prolonged the survival of mice with orthotopic tumor, without causing toxic signs. This study indicates the potential of the targeted nanoformulation as an emerging chemotherapy option for treating HCC.

Ultrasound-guided chemoradiotherapy of breast cancer using smart methotrexate-loaded perfluorohexane nanodroplets

Chemoradiotherapy with controlled-release nanocarriers such as sono-sensitive nanodroplets (NDs) can enhance the anticancer activity of chemotherapy medicines and reduces normal tissue side effects. In this study, folic acid-functionalized methotrexate-loaded perfluorohexane NDs with alginate shell (FA-MTX/PFH@alginate NDs) were synthesized, characterized, and their potential for ultrasound-guided chemoradiotherapy of breast cancer was investigated in vitro and in vivo. The cancer cell (4T1) viabilities and surviving fractions after NDs and ultrasound treatments were significantly decreased. However, this reduction was much more significant for ultrasound in combination with X-ray irradiation. The in vitro and in vivo results confirmed that MTX-loaded NDs are highly biocompatible and they have no significant hemolytic activity and organ toxicity. Furthermore, the in vivo results indicated that the FA-MTX/PFH@alginate NDs were accumulated selectively in the tumor region. In conclusion, FA-functionalized MTX/PFH@alginate NDs have a great theranostic performance for ultrasound-controlled drug delivery in combination with radiotherapy of breast cancer.

Carbon dot incorporated mesoporous silica nanoparticles for targeted cancer therapy and fluorescence imaging†

A new and efficient theranostic nanoplatform was developed via a green approach for targeted cancer therapy and fluorescence imaging, without the use of any anticancer chemotherapeutic drugs. Toward this aim, monodisperse and spherical mesoporous silica nanoparticles (MSNs) of approximately 50 nm diameter were first synthesized using the sol–gel method and loaded with hydrothermally synthesized anticancer carbon dots (CDs). The resulting MSNs-CDs were then functionalized with chitosan and targeted by an anti-MUC1 aptamer, using the glutaraldehyde cross-linker, and fully characterized by TEM, FE-SEM, EDS, FTIR, TGA, XRD, and BET analysis. Potent and selective anticancer activity was obtained against MCF-7 and MDA-MB-231 cancer cells with the maximum cell mortalities of 66.2 ± 1.97 and 71.8 ± 3%, respectively, after 48 h exposure with 100 μg mL⁻¹ of the functionalized MSNs-CDs. The maximum mortality of 40.66 ± 1.3% of normal HUVEC cells was obtained under the same conditions. Based on the results of flowcytometry analysis, the apoptotic mediated cell death was recognized as the main anticancer mechanism of the MSNs-CDs. The fluorescence imaging of MCF-7 cancer cells was also studied after exposure with MSNs-CDs. The overall results indicated the high potential of the developed nanoplatform for targeted cancer theranostics.

Efficient cancer therapy and fluorescence imaging was obtained by aptamer targeted mesoporous silica nanoparticles incorporating carbon dots.

Nanotechnology strategies for hepatocellular carcinoma diagnosis and treatment

Hepatocellular carcinoma (HCC) is a common malignancy threatening human health, and existing diagnostic and therapeutic techniques are facing great challenges. In the last decade or so, nanotechnology has been developed and improved for tumor diagnosis and treatment. For example, nano-intravenous injections have been approved for malignant perivascular epithelioid cell tumors. This article provides a comprehensive review of the applications of nanotechnology in HCC in recent years: (I) in radiological imaging, magnetic resonance imaging (MRI), fluorescence imaging (FMI) and multimodality imaging. (II) For diagnostic applications in HCC serum markers. (III) As embolic agents in transarterial chemoembolization (TACE) or directly as therapeutic drugs. (IV) For application in photothermal therapy and photodynamic therapy. (V) As carriers of chemotherapeutic drugs, targeted drugs, and natural plant drugs. (VI) For application in gene and immunotherapy. Compared with the traditional methods for diagnosis and treatment of HCC, nanoparticles have high sensitivity, reduce drug toxicity and have a long duration of action, and can also be combined with photothermal and photodynamic multimodal combination therapy. These summaries provide insights for the further development of nanotechnology applications in HCC.

Nanoparticle-Based Therapeutics to Overcome Obstacles in the Tumor Microenvironment of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is still a main health concern around the world, with a rising incidence and high mortality rate. The tumor-promoting components of the tumor microenvironment (TME) play a vital role in the development and metastasis of HCC. TME-targeted therapies have recently drawn increasing interest in the treatment of HCC. However, the short medication retention time in TME limits the efficiency of TME modulating strategies. The nanoparticles can be elaborately designed as needed to specifically target the tumor-promoting components in TME. In this regard, the use of nanomedicine to modulate TME components by delivering drugs with protection and prolonged circulation time in a spatiotemporal manner has shown promising potential. In this review, we briefly introduce the obstacles of TME and highlight the updated information on nanoparticles that modulate these obstacles. Furthermore, the present challenges and future prospects of TME modulating nanomedicines will be briefly discussed.

Targeted Molecular Imaging Probes Based on Magnetic Resonance Imaging for Hepatocellular Carcinoma Diagnosis and Treatment

Hepatocellular carcinoma (HCC) is the sixth most commonly malignant tumor and the third leading cause of cancer-related death in the world, and the early diagnosis and treatment of patients with HCC is core in improving its prognosis. The early diagnosis of HCC depends largely on magnetic resonance imaging (MRI). MRI has good soft-tissue resolution, which is the international standard method for the diagnosis of HCC. However, MRI is still insufficient in the diagnosis of some early small HCCs and malignant nodules, resulting in false negative results. With the deepening of research on HCC, researchers have found many specific molecular biomarkers on the surface of HCC cells, which may assist in diagnosis and treatment. On the other hand, molecular imaging has progressed rapidly in recent years, especially in the field of cancer theranostics. Hence, the preparation of molecular imaging probes that can specifically target the biomarkers of HCC, combined with MRI testing in vivo, may achieve the theranostic purpose of HCC in the early stage. Therefore, in this review, taking MR imaging as the basic point, we summarized the recent progress regarding the molecular imaging targeting various types of biomarkers on the surface of HCC cells to improve the theranostic rate of HCC. Lastly, we discussed the existing obstacles and future prospects of developing molecular imaging probes as HCC theranostic nanoplatforms.

Phase-shift nanodroplets as an emerging sonoresponsive nanomaterial for imaging and drug delivery applications

Nanodroplets - emerging phase-changing sonoresponsive materials - have attracted substantial attention in biomedical applications for both tumour imaging and therapeutic purposes due to their unique response to ultrasound. As ultrasound is applied at different frequencies and powers, nanodroplets have been shown to cavitate by the process of acoustic droplet vapourisation (ADV), causing the development of mechanical forces which promote sonoporation through cellular membranes. This allows drugs to be delivered efficiently into deeper tissues where tumours are located. Recent reviews on nanodroplets are mostly focused on the mechanism of cavitation and their applications in biomedical fields. However, the chemistry of the nanodroplet components has not been discussed or reviewed yet. In this review, the commonly used materials and preparation methods of nanodroplets are summarised. More importantly, this review provides examples of variable chemistry components in nanodroplets which link them to their efficiency as ultrasound-multimodal imaging agents to image and monitor drug delivery. Finally, the drawbacks of current research, future development, and future direction of nanodroplets are discussed.