T1-T2 molecular magnetic resonance imaging of renal carcinoma cells based on nano-contrast agents

Aptamer-functionalized nanomaterials (AFNs) for therapeutic management of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) represents one of the deadliest cancers globally, making the search for more effective diagnostic and therapeutic approaches particularly crucial. Aptamer-functionalized nanomaterials (AFNs), an innovative nanotechnology, have paved new pathways for the targeted diagnosis and treatment of HCC. Initially, we outline the epidemiological background of HCC and the current therapeutic challenges. Subsequently, we explore in detail how AFNs enhance diagnostic and therapeutic efficiency and reduce side effects through the specific targeting of HCC cells and the optimization of drug delivery. Furthermore, we address the challenges faced by AFNs in clinical applications and future research directions, with a particular focus on enhancing their biocompatibility and assessing long-term effects. In summary, AFNs represent an avant-garde therapeutic approach, opening new avenues and possibilities for the diagnosis and treatment of HCC.

Multi-modal brain tumor segmentation via conditional synthesis with Fourier domain adaptation

Accurate brain tumor segmentation is critical for diagnosis and treatment planning, whereby multi-modal magnetic resonance imaging (MRI) is typically used for analysis. However, obtaining all required sequences and expertly labeled data for training is challenging and can result in decreased quality of segmentation models developed through automated algorithms. In this work, we examine the possibility of employing a conditional generative adversarial network (GAN) approach for synthesizing multi-modal images to train deep learning-based neural networks aimed at high-grade glioma (HGG) segmentation. The proposed GAN is conditioned on auxiliary brain tissue and tumor segmentation masks, allowing us to attain better accuracy and control of tissue appearance during synthesis. To reduce the domain shift between synthetic and real MR images, we additionally adapt the low-frequency Fourier space components of synthetic data, reflecting the style of the image, to those of real data. We demonstrate the impact of Fourier domain adaptation (FDA) on the training of 3D segmentation networks and attain significant improvements in both the segmentation performance and prediction confidence. Similar outcomes are seen when such data is used as a training augmentation alongside the available real images. In fact, experiments on the BraTS2020 dataset reveal that models trained solely with synthetic data exhibit an improvement of up to 4% in Dice score when using FDA, while training with both real and FDA-processed synthetic data through augmentation results in an improvement of up to 5% in Dice compared to using real data alone. This study highlights the importance of considering image frequency in generative approaches for medical image synthesis and offers a promising approach to address data scarcity in medical imaging segmentation.

Study of paraCEST response on six-coordinated Co(II) and Ni(II) complexes of a pyridine-tetraamide-based ligand

This study highlights the successful synthesis of a potential ligand, 2,2',2'',2'''-((pyridine-2,6-diylbis(methylene))bis(azanetriyl))tetraacetamide (PATA), along with its corresponding Co(II) and Ni(II) complexes for paraCEST-based agents. X-ray diffraction data confirmed that both the complexes are six coordinated with distorted octahedral geometries, but only the [Co(PATA)]2+ complex has a good structural feature to show paraCEST activity. After a thorough characterization of the ligand and both of its complexes, various studies, including solution-state magnetic properties, redox properties, temperature, and pH variation studies, were carried out. [Co(PATA)]2+ remained inert in the presence of competing ions, under acidic conditions, at high temperatures, and in the physiological pH range. The paraCEST response of [Co(PATA)]2+ has been measured in the presence of HEPES buffer medium, and a high paraCEST feature was discovered at both 37 and 25 °C. The pH variation paraCEST studies were carried out and the exchange rate constant of the probe at 37 and 25 °C was also determined. However, due to the fast exchange of water protons, the [Ni(PATA)(OH2)]2+ complex remained inactive in the CEST process.

Theranostic Lipid Nanoparticles for Renal Cell Carcinoma

Renal cell carcinoma (RCC) is a common urological malignancy and represents a leading threat to healthcare. Recent years have seen a series of progresses in the early diagnosis and management of RCC. Theranostic lipid nanoparticles (LNPs) are increasingly becoming one of the focuses in this field, because of their suitability for tumor targeting and multimodal therapy. LNPs can be precisely fabricated with desirable chemical compositions and biomedical properties, which closely match the physiological characteristics and clinical needs of RCC. Herein, a comprehensive review of theranostic LNPs is presented, emphasizing the generic tool nature of LNPs in developing advanced micro-nano biomaterials. It begins with a brief overview of the compositions and formation mechanism of LNPs, followed with an introduction to kidney-targeting approaches, such as passive, active, and stimulus responsive targeting. With examples provided, a series of modification strategies for enhancing the tumor targeting and functionality of LNPs are discussed. Thereafter, research advances on applications of these LNPs for RCC including bioimaging, liquid biopsy, drug delivery, physical therapy, and gene therapy are summarized and discussed from an interdisciplinary perspective. The final part highlights the milestone achievements of translation medicine, current challenges as well as future development directions of LNPs for the diagnosis and treatment of RCC.

cRGD-Conjugated GdIO Nanoclusters for the Theranostics of Pancreatic Cancer through the Combination of T1-T2 Dual-Modal MRI and DTX Delivery

Clinically, magnetic resonance imaging (MRI) often uses contrast agents (CAs) to improve image contrast, but single-signal MRI CAs are often susceptible to calcification, hemorrhage, and magnetic sensitivity. Herein, iron acetylacetone and gadolinium acetylacetone were used as raw materials to synthesize a T1-T2 dual-mode imaging gadolinium-doped iron oxide (GdIO) nanocluster. Moreover, to endow the nanoclusters with targeting properties and achieve antitumor effects, the cyclic Arg-Gly-Asp (cRGD) peptide and docetaxel (DTX) were attached to the nanocluster surface, and the efficacy of the decorated nanoclusters against pancreatic cancer was evaluated. The final synthesized material cRGD-GdIO-DTX actively targeted αvβ3 on the surface of Panc-1 pancreatic cancer cells. Compared with conventional passive targeting, the enrichment of cRGD-GdIO-DTX in tumor tissues improved, and the diagnostic accuracy was significantly enhanced. Moreover, the acidic tumor microenvironment triggered the release of DTX from cRGD-GdIO-DTX, thus achieving tumor treatment. The inhibition of the proliferation of SW1990 and Panc-1 pancreatic cancer cells by cRGD-GdIO-DTX was much stronger than that by the untargeted GdIO-DTX and free DTX in vitro. In addition, in a human pancreatic cancer xenograft model, cRGD-GdIO-DTX considerably slowed tumor development and demonstrated excellent magnetic resonance enhancement. Our results suggest that cRGD-GdIO-DTX has potential applications for the precise diagnosis and efficient treatment of pancreatic cancer.

Shape programmable T1-T2 dual-mode MRI nanoprobes for cancer theranostics

The shape effect is an important parameter in the design of novel nanomaterials. Engineering the shape of nanomaterials is an effective strategy for optimizing their bioactive performance. Nanomaterials with a unique shape are beneficial to blood circulation, tumor targeting, cell uptake, and even improved magnetism properties. Therefore, magnetic resonance imaging (MRI) nanoprobes with different shapes have been extensively focused on in recent years. Different from other multimodal imaging techniques, dual-mode MRI can provide imaging simultaneously by a single instrument, which can avoid differences in penetration depth, and the spatial and temporal resolution of multiple imaging devices, and ensure the accurate matching of spatial and temporal imaging parameters for the precise diagnosis of early tumors. This review summarizes the latest developments of nanomaterials with various shapes for T₁-T₂ dual-mode MRI, and highlights the mechanism of how shape intelligently affects nanomaterials' longitudinal or transverse relaxation, namely sphere, hollow, core-shell, cube, cluster, flower, dumbbell, rod, sheet, and bipyramid shapes. In addition, the combination of T₁-T₂ dual-mode MRI nanoprobes and advanced therapeutic strategies, as well as possible challenges from basic research to clinical transformation, are also systematically discussed. Therefore, this review will help others quickly understand the basic information on dual-mode MRI nanoprobes and gather thought-provoking ideas to advance the subfield of cancer nanomedicine.

Nanomedicine for renal cell carcinoma: imaging, treatment and beyond

The kidney is a vital organ responsible for maintaining homeostasis in the human body. However, renal cell carcinoma (RCC) is a common malignancy of the urinary system and represents a serious threat to human health. Although the overall survival of RCC has improved substantially with the development of cancer diagnosis and management, there are various reasons for treatment failure. Firstly, without any readily available biomarkers, timely diagnosis has been greatly hampered. Secondly, the imaging appearance also varies greatly, and its early detection often remains difficult. Thirdly, chemotherapy has been validated as unavailable for treating renal cancer in the clinic due to its intrinsic drug resistance. Concomitant with the progress of nanotechnological methods in pharmaceuticals, the management of kidney cancer has undergone a transformation in the recent decade. Nanotechnology has shown many advantages over widely used traditional methods, leading to broad biomedical applications ranging from drug delivery, prevention, diagnosis to treatment. This review focuses on nanotechnologies in RCC management and further discusses their biomedical translation with the aim of identifying the most promising nanomedicines for clinical needs. As our understanding of nanotechnologies continues to grow, more opportunities to improve the management of renal cancer are expected to emerge.

Gd2O3-mesoporous silica/gold nanoshells: A potential dual T1/T2 contrast agent for MRI-guided localized near-IR photothermal therapy

A promising clinical trial utilizing gold-silica core-shell nanostructures coated with polyethylene glycol (PEG) has been reported for near-infrared (NIR) photothermal therapy (PTT) of prostate cancer. The next critical step for PTT is the visualization of therapeutically relevant nanoshell (NS) concentrations at the tumor site. Here we report the synthesis of PEGylated Gd₂O₃-mesoporous silica/gold core/shell NSs (Gd₂O₃-MS NSs) with NIR photothermal properties that also supply sufficient MRI contrast to be visualized at therapeutic doses (≥10⁸ NSs per milliliter). The nanoparticles have r₁ relaxivities more than three times larger than those of conventional T₁ contrast agents, requiring less concentration of Gd³⁺ to observe an equivalent signal enhancement in T₁-weighted MR images. Furthermore, Gd₂O₃-MS NS nanoparticles have r₂ relaxivities comparable to those of existing T₂ contrast agents, observed in agarose phantoms. This highly unusual combination of simultaneous T₁ and T₂ contrast allows for MRI enhancement through different approaches. As a rudimentary example, we demonstrate T₁/T₂ ratio MR images with sixfold contrast signal enhancement relative to its T₁ MRI and induced temperature increases of 20 to 55 °C under clinical illumination conditions. These nanoparticles facilitate MRI-guided PTT while providing real-time temperature feedback through thermal MRI mapping.

Applications and Biocompatibility of Mesoporous Silica Nanocarriers in the Field of Medicine

Mesoporous silica nanocarrier (MSN) preparations have a wide range of medical applications. Studying the biocompatibility of MSN is an important part of clinical transformation. Scientists have developed different types of mesoporous silica nanocarriers (MSNs) for different applications to realize the great potential of MSNs in the field of biomedicine, especially in tumor treatment. MSNs have achieved good results in diagnostic bioimaging, tissue engineering, cancer treatment, vaccine development, biomaterial application and diagnostics. MSNs can improve the therapeutic efficiency of drugs, introduce new drug delivery strategies, and provide advantages that traditional drugs lack. It is necessary not only to innovate MSNs but also to comprehensively understand their biological distribution. In this review, we summarize the various medical uses of MSN preparations and explore the factors that affect their distribution and biocompatibility in the body based on metabolism. Designing more reasonable therapeutic nanomedicine is an important task for the further development of the potential clinical applications of MSNs.

Aspects of high-performance and bio-acceptable magnetic nanoparticles for biomedical application

This review covers extensively the synthesis & surface modification, characterization, and application of magnetic nanoparticles. For biomedical applications, consideration should be given to factors such as design strategies, the synthesis process, coating, and surface passivation. The synthesis method regulates post-synthetic change and specific applications in vitro and in vivo imaging/diagnosis and pharmacotherapy/administration. Special insights have been provided on biodistribution, pharmacokinetics, and toxicity in a living system, which is imperative for their wider application in biology. These nanoparticles can be decorated with multiple contrast agents and thus can also be used as a probe for multi-mode imaging or double/triple imaging, for example, MRI-CT, MRI-PET. Similarly loading with different drug molecules/dye/fluorescent molecules and integration with other carriers have found application not only in locating these particles in vivo but simultaneously target drug delivery/hyperthermia inside the body. Studies are underway to collect the potential of these magnetically driven nanoparticles in various scientific fields such as particle interaction, heat conduction, imaging, and magnetism. Surely, this comprehensive data will help in the further development of advanced techniques for theranostics based on high-performance magnetic nanoparticles and will lead this research area in a new sustainable direction.

Gold nanoparticles meet medical radionuclides

Thanks to their unique optical and physicochemical properties, gold nanoparticles have gained increased interest as radiosensitizing, photothermal therapy and optical imaging agents to enhance the effectiveness of cancer detection and therapy. Furthermore, their ability to carry multiple medically relevant radionuclides broadens their use to nuclear medicine SPECT and PET imaging as well as targeted radionuclide therapy. In this review, we discuss the radiolabeling process of gold nanoparticles and their use in (multimodal) nuclear medicine imaging to better understand their specific distribution, uptake and retention in different in vivo cancer models. In addition, radiolabeled gold nanoparticles enable image-guided therapy is reviewed as well as the enhancement of targeted radionuclide therapy and nanobrachytherapy through an increased dose deposition and radiosensitization, as demonstrated by multiple Monte Carlo studies and experimental in vitro and in vivo studies.

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.

Tumor-targeted Gd-doped mesoporous Fe3O4 nanoparticles for T1/T2 MR imaging guided synergistic cancer therapy

In this study, a novel intelligent nanoplatform to integrate multiple imaging and therapeutic functions for targeted cancer theranostics. The nanoplatform, DOX@Gd-MFe₃O₄ NPs, was constructed Gd-doped mesoporous Fe₃O₄ nanoparticles following with the doxorubicin (DOX) loading in the mesopores of the NPs. The DOX@Gd-MFe₃O₄ NPs exhibited good properties in colloidal dispersity, photothermal conversion, NIR triggered drug release, and high T₁/T₂ relaxicity rate (r₁=9.64 mM⁻¹s⁻¹, r₂= 177.71 mM⁻¹s⁻¹). Benefiting from the high MR contrast, DOX@Gd-MFe₃O₄ NPs enabled simultaneous T₁/T₂ dual-modal MR imagining on 4T1 bearing mice in vivo and the MR contrast effect was further strengthened by external magnetic field. In addition, the DOX@Gd-MFe₃O₄ NPs revealed the strongest inhibition to the growth of 4T1 in vitro and in vivo under NIR irradiation and guidance of external magnetic field. Moreover, biosafety was also validated by in vitro and in vivo tests. Thus, the prepared DOX@Gd-MFe₃O₄ NPs would provide a promising intelligent nanoplatform for dual-modal MR imagining guided synergistic therapy in cancer theranostics.

Aptamer-Driven Toxin Gene Delivery in U87 Model Glioblastoma Cells

A novel suicide gene therapy approach was tested in U87 MG glioblastoma multiforme cells. A 26nt G-rich double-stranded DNA aptamer (AS1411) was integrated into a vector at the 5' of a mammalian codon-optimized saporin gene, under CMV promoter. With this plasmid termed "APTSAP", the gene encoding ribosome-inactivating protein saporin is driven intracellularly by the glioma-specific aptamer that binds to cell surface-exposed nucleolin and efficiently kills target cells, more effectively as a polyethyleneimine (PEI)-polyplex. Cells that do not expose nucleolin at the cell surface such as 3T3 cells, used as a control, remain unaffected. Suicide gene-induced cell killing was not observed when the inactive saporin mutant SAPKQ DNA was used in the (PEI)-polyplex, indicating that saporin catalytic activity mediates the cytotoxic effect. Rather than apoptosis, cell death has features resembling autophagic or methuosis-like mechanisms. These main findings support the proof-of-concept of using PEI-polyplexed APTSAP for local delivery in rat glioblastoma models.

A novel sodium-fluorescent crystal

In this work, a novel sodium-fluorescent crystal (Na-FS) was synthesized from 4-dimethylaminobenzoic acid and sodium hydroxide by one-pot hydrothermal method. The structure and conformation of Na-FS were confirmed by single-crystal X-ray diffraction and scanning electron microscope, and the optical properties were studied by fluorescence spectrometer. The results showed that: Na-FS was a triclinic crystal, space group was P-1, cell parameters a, b and c were 10.5113(3), 15.9198(5) and 15.9560(5) Å, respectively, and the number of independent atoms Z in a structure cell was two. Additionally, Na-FS has a blue fluorescence emission (around 360 nm under excited at the range of 230-300 nm) with great photostability and photobleaching resistance, and the quantum yield of Na-FS is 30.58%.

Cyclic RGD functionalized liposomes targeted to activated platelets for thrombosis dual-mode magnetic resonance imaging

Thrombotic disease is a serious threat to human health. The rapid and accurate detection of thrombosis is still a clinical challenge. To achieve the accurate diagnosis of thrombosis with magnetic resonance imaging (MRI), nanomaterials-based contrast agents have been developed in recent years. In this study, cyclic RGD functionalized liposomes targeted to the activated platelets are developed for thrombosis dual-mode MRI. The cyclic RGD functionalized liposomes (cRGD@MLP-Gd) encapsulated with gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA) and superparamagnetic iron oxide (SPIO) are prepared, and their thrombus-targeted T1 and T2 MRI potential is evaluated in vitro and in vivo. Results show that cRGD@MLP-Gd could actively bind to the activated platelets and gradually accumulate at the thrombus site with a T1 - T2 contrast enhancement imaging effect in vitro. In in vivo MRI experiments, cRGD@MLP-Gd exhibits a T2 contrast enhancement at 1 h after intravenous administration, followed by a visibly larger T1 contrast enhancement at the thrombus site. This dynamic property showed that cRGD@MLP-Gd could actively bind to thrombus and possessed an enhanced T1 and T2 dual-mode MRI effect in vivo. Our results establish the characterization, feasibility and superiority of cRGD@MLP-Gd for the rapid identification of thrombosis, showing great potential to improve diagnostic accuracy and sensitivity to thrombosis of the MRI technique.

Targeting Strategies for Renal Cancer Stem Cell Therapy

Renal cell carcinoma (RCC) is an intractable genitourinary malignancy that accounts for approximately 4% of adult malignancies. Currently, there is no approved targeted therapy for RCC that has yielded durable remissions, and they remain palliative in intent. Emerging evidence has indicated that renal tumorigenesis and RCC treatment-resistance may originate from renal cancer stem cells (CSCs) with tumor-initiating capacity (CSC hypothesis). A better understanding of the mechanism underlying renal CSCs will help to dissect RCC heterogeneity and drug treatment efficiency, to promote more personalized and targeted therapies. In this review, we summarized the stem cell characteristics of renal CSCs. We outlined the targeting strategies and challenges associated with developing therapies that target renal CSCs angiogenesis, immunosuppression, signaling pathways, surface biomarkers, microRNAs and nanomedicine. In conclusion, CSCs are an important role in renal carcinogenesis and represent a valid target for treatment of RCC patients.

Spontaneous reduction of KMnO4 with MoS2 quantum dots for glutathione sensing in tumors

Transition-metal dichalcogenides (TMDCs) have attracted a lot of attention due to their electronic, optical, mechanical, and catalytic properties. In addition, TMDCs possess rich redox chemistry that enables the decoration of metal nanoparticles directly on their surfaces. In this paper, MnO2/MoS2 nanocomplexes were obtained by the spontaneous reduction of KMnO4 with MoS2 QDs as the reductive agent. The formed MnO2/MoS2 nanocomplexes exhibited activated fluorescence and MR imaging signal in the presence of glutathione (GSH). After conjugation with an AS1411 aptamer, specific in vivo MR imaging and fluorescence labeling of the 786-O tumor cells were realized, showing their promising potential for biomedical applications.

Cancer treatment in the lymphatic system: A prospective targeting employing nanostructured systems

Cancer related to lymphangiogenesis has gained a great deal of attention in recent decades ever since specific markers of this intriguing system were discovered. Unlike the blood system, the lymphatic system has unique features that can advance cancer in future metastasis, or, conversely, can provide an opportunity to prevent or treat this disease that affects people worldwide. The aim of this review is to show the recent research of cancer treatment associated with the lymphatic system, considered one of the main gateways for disseminating metastatic cells to distant organs. Nanostructured systems based on theranostics and immunotherapies can offer several options for this complex disease. Precision targeting and accumulation of nanomaterials into the tumor sites and their elimination, or targeting the specific immune defense cells to promote optimal regression of cancer cells are highlighted in this paper. Moreover, therapies based on nanostructured systems through lymphatic systems may reduce the side effects and toxicity, avoid first pass hepatic metabolism, and improve patient recovery. We emphasize the general understanding of the association between the immune and lymphatic systems, their interaction with tumor cells, the mechanisms involved and the recent developments in several nanotechnology treatments related to this disease.

Water-Nanomaterial Interaction to Escalate Twin-Mode Magnetic Resonance Imaging

Molecular imaging has gained utmost importance in the recent past in early diagnosis of diseases. In comparison to other imaging modalities, magnetic resonance imaging (MRI) has proven to extend its abilities not only for its usage of non-ionizing radiation but also for the high spatial resolution in soft tissues. A major limitation faced by MRI is the sensitivity in detecting diseased conditions until a certain stage. At present, this limitation is overcome with the use of contrast agents that show potential in altering the T1 and T2 relaxation times of the hydrogen protons. This modulation to the relaxation times leads to better contrast differences based on the type of contrast agent and the pulse sequence being engaged for acquiring images. Water molecules, as the major contributor of hydrogen protons, are proven to interact with such contrast agents. Major drawbacks noted with the marketed MRI contrast agents are their toxicity and renal clearance. To conquer these issues, magnetic nanomaterials are being researched for their abilities to match the contrast enhancement offered by traditional agents reducing their drawbacks. Furthermore, comparative diagnosis with both T1 and T2 contrast at the same time has also interested investigators. To achieve this, twin mode T1 and T2 weighted contrast agents are developed utilizing the remarkable properties extended by magnetic nanoplatforms. As a step forward, multimodal imaging agents are also being engineered based on these magnetic nanoplatforms that will generate cross-verified diagnoses using multiple imaging modalities with a unique imaging agent. This review starts by introducing the basics of MRI with major focus on the typical interactions of water molecules with a variety of magnetic nanomaterials. The review also concentrates on the clinical needs and nanomaterials available for twin T1 and T2 contrast with a minor introduction to multimodal imaging agents. In conclusion, the advent of MRI with the advantages offered by magnetic nanomaterials is summarized, leading to insights for future developments.

Aptamers in Diagnostic and Molecular Imaging Applications

The origin of the term diagnostic comes from the Greek word gnosis, meaning "to know." In medicine, a diagnostic can predict the pathology risk, disease status, treatment, and prognosis, even following therapy. An early and correct diagnosis is necessary for an efficient treatment. Moreover, it is possible to predict if and why a therapy will be successful or fail, enabling the timely application of alternative therapeutic strategies. Available diagnostics are due to the advances in biotechnology; however, more sensitive, low-cost, and noninvasive methodologies are still a challenge. Knowledge about molecular characteristics provide personalized information, which is the goal of future medicine. Today, multiple diagnostic techniques have emerged, with which it is possible to distinguish molecular patterns.In this way, aptamers are the perfect tools to recognize molecular targets and can be easily modified to confer additional functions. Their versatile characteristics and low cost make aptamers ideal for diagnostic applications.This chapter is a review of aptamer-based diagnostics in biomedicine, with a special focus on probe design and molecular imaging. Graphical Abstract.

GOLPH3 Regulates Exosome miRNA Secretion in Glioma Cells

We aimed to examine whether golgi protein GOLPH3 could affect the secretion of glioma cell-derived exosomes. The exosomes were extracted by ultra-centrifugation from the supernatant of U251 and U87 cell cultures and identified by transmission electron microscopy (TEM), Malvern analyzer, and western blot. The quantity of exosomes was examined by measuring the total protein levels and the number of multiple vesicle bodies (MVBs), the source of exosomes. The exosome miRNAs were analyzed by high-throughput sequencing followed by GO and KEGG analysis, and validated by qRT-PCR. GOLPH3 could not affect the total protein levels of exosomes and the number of MVBs. However, we found 149 differentially expressed miRNAs in exosomes between vector and GOLPH3 over-expression group, and 14 miRNAs were only examined in GOLPH3 over-expression cells. The predicted target genes of these miRNAs had functions in binding and catalytic activity, which were enriched in the pathways of endocytosis, RNA transportation, thyroid hormone signaling and miRNAs in cancer. GOLPH3 could not affect the quantity of exosomes, but rather contribute to miRNA expression in exosomes, which may play some functions in the promotion effect of GOLPH3 on glioma development.

Photo-Functionalized Magnetic Nanoparticles as a Nanocarrier of Photodynamic Anticancer Agent for Biomedical Theragnostics

Various theragnostic agents have been devised and developed as cancer treatments; however, existing agents are often limited by their specific functions and complexities. Here, we report multifunctional magnetite (Fe₃O₄) nanoparticles functionalized with chlorin e6 (Ce6) and folic acid (FA) using a simple fabrication process to be used as theragnostic agents in photodynamic therapy (PDT). The effectiveness of cellular uptake of Fe3O4-Ce6-FA nanoparticles (FCF NPs) and its visualization as well as the photodynamic anticancer activities were evaluated. The mechanism of cancer cell death by the FCF NPs was also verified with qualitative and quantitative methods. Results indicate that FCF NPs have good penetration efficacy, resulting in excellent in vitro fluorescence and magnetic resonance imaging in cancer cells. FCF NPs exhibited promising anticancer activity in an irradiation time- and FCF NPs-dose-dependent manner in various cancer cell lines, leading to apoptotic cell death via morphological changes in cell membrane, nuclear, and DNA damage, and via overexpression of apoptosis-related genes, such as ZFP36L1, CYR61, GADD45G, caspases-2, -3, -9, 10, and -14. This study suggests that FCF NPs may be safely used in cancer therapy via PDT and could be a versatile therapeutic tool and biocompatible theragnostic agent, which may be used in diagnostic imaging.

Multifunctional MIL-Cur@FC as a theranostic agent for magnetic resonance imaging and targeting drug delivery: in vitro and in vivo study

Owing to the importance of multifunctional theranostics as promising systems to overcome key problems of conventional cancer therapy, in this study a multifunctional metal-organic framework-based (MOF) theranostic system was prepared and applied as intelligent theranostic systems in cancer. Iron-based MOF, MIL-88B, in a multi-faceted shape was initially prepared. Curcumin (Cur) was then loaded into the pores of MIL and folic acid-chitosan conjugate (FC) was finally coated on the surface of the carrier to accomplish cancer-specific targeting properties. MTT assay revealed perfect cytocompatibility of the system and selective toxicity against cancerous cells. In vivo MRI images showed high tumour uptake for MIL-Cur@FC and high T₁-T₂ contrast effect. The growth inhibiting efficiencies of MIL-Cur@FC on M109 tumour bearing Balb/C mice without reducing their body weight showed maximum tumour eradication with no significant toxicities. Due to the outstanding features of the system achieved from in vitro and in vivo studies, we believe that this study will provide a novel approach for developing targeted theranostic agents in cancer diagnosis and treatment.

AS1411 aptamer modified carbon dots via polyethylenimine-assisted strategy for efficient targeted cancer cell imaging

OBJECTIVES

Carbon dots (CDs), as a fascinating class of fluorescent carbon nanomaterials, have been proven to be powerful tools in the field of bioimaging and biosensing due to their small size, suitable photostability and favourable biocompatibility. However, the cellular uptake of free CDs lacks selectivity and the same negative charges as cell membranes may cause inefficient cell internalization. In this study, an efficient detecting and targeting nanosystem was developed based on the DNA aptamer AS1411 modified CDs with polyethyleneimine (PEI) as connecting bridge.

MATERIALS AND METHODS

Hydrothermally prepared CDs were assembled with positive-charged PEI, followed by conjugation with AS1411 through electrostatic interaction to form CDs-PEI-AS1411 nanocomplexes. The CDs, CDs-PEI and CDs-PEI-AS1411 were characterized by transmission electron microscopy (TEM), fourier transform infrared (FTIR) spectra, UV-vis spectra, zeta potential measurements and capillary electrophoresis characterizations. The cytotoxicity investigation of the CDs-PEI-AS1411 and CDs-PEI in both MCF-7 and L929 cells was carried out by the CCK-8 assay. The cellular uptake of the CDs-PEI-AS1411 was studied with confocal microscopy and flow cytometry.

RESULTS

The as-prepared nanosystem possessed good photostability and no obvious cytotoxicity. On the basis of the confocal laser scanning microscope observation and the flow cytometry studies, the cellular uptake of CDs-PEI-AS1411 nanosystem in MCF-7 cells was significantly higher than that of L929 cells, which revealed the highly selective detection ability of nucleolin-positive cells.

CONCLUSIONS

The results of this study indicated that the CDs-PEI-AS1411 nanosystem had a potential value in cancer cell targeted imaging.

Synthesis Of PEG-Coated, Ultrasmall, Manganese-Doped Iron Oxide Nanoparticles With High Relaxivity For T1/T2 Dual-Contrast Magnetic Resonance Imaging

BACKGROUND

Beyond magnetic resonance imaging (MRI), which has been widely used clinically, molecular MRI (mMRI) can further provide qualitative and quantitative information at the cellular and molecular levels. However, the diagnostic accuracy may not be satisfactory via single-contrast mMRI due to some interferences in vivo. T1/T2 dual-contrast MRI using the same contrast agent (CA) could significantly improve the detection accuracy. Therefore, in this study, we fabricated poly(ethylene glycol) (PEG)-coated, manganese-doped iron oxide nanocomposites (Mn-IONPs@PEG) as T1/T2 dual-contrast CA, and evaluated its feasibility of T1/T2 dual-contrast MRI in vitro and in vivo.

METHODS

Mn-IONPs were prepared by the thermal decomposition of iron-eruciate and manganese-oleate complexes and were coated with 1,2-Distearoyl-sn-glycero-3-phosphoethanolamine-N-(methoxy[polyethylene glycol]-2000) (DSPE-PEG 2000). The physicochemical properties and cytotoxicity of the Mn-IONPs were fully characterized, followed by MRI in vitro and in vivo.

RESULTS

Ultrasmall 3 nm-sized nanoparticles were successfully prepared and were identified using transmission electron microscopy (TEM), high-resolution TEM, and X-ray diffraction. After coating with DSPE-PEG, the Mn-IONPs@PEG displayed excellent hydrophilicity and good biocompatibility. Due to the manganese-doping and PEG coating, the Mn-IONPs@PEG showed good relaxivity in vitro. Especially, the Mn-IONPs@PEG coated with DSPE-PEG following a mass ratio to Mn-IONPs of 1:20 showed harmonious longitudinal relaxivity (r 1 = 7.1 mM-1s-1) and transversal relaxivity (r 2 = 120.9 mM-1s-1), making it a better candidate for T1/T2 dual-contrast mMRI. After administrated via a caudal vein, the Mn-IONPs@PEG can induce significant enhancement in both T1-weighted and T2-weighted MR images and the time at 10 mins after injection was regarded as a suitable time for imaging because both the T1 and T2 enhancement were optimum at that time.

CONCLUSION

The obtained Mn-IONPs@PEG exhibited good r 1 and r 2 and was a reasonable candidate for T1/T2 dual-contrast mMRI.

Multi-contrast imaging information of coronary artery wall based on magnetic resonance angiography

In order to explore the most suitable image acquisition method for coronary artery wall, the display ability and image quality of segmentation breath-holding target volume acquisition method (the breath-holding method) and real-time navigation whole-hearted acquisition method (the navigation method) of coronary artery magnetic resonance angiography (CMRA) were compared. 26 healthy volunteers were selected to accept the CMRA in 1.5 tunnels magneto-resistance (TMR) equipment by the 2 acquisition methods respectively. The arteries were divided into 9 segments according to the standards of the American Heart Association (AHA). The images were evaluated by 2 magnetic resonance physicians. Satisfaction rate and success rate of each segment of the coronary artery were counted. The results showed that the signal to noise ratio (SNR) and the carrier to noise ratio (CNR) of the images obtained by the breath-holding method were higher than those obtained by the navigation method (P<0.05). Therefore, the segmentation breath-holding target volume acquisition method is proved to have a higher image quality and the simpler and more convenient operations, which is more suitable for the acquisition of positioning images of CMRA.

Contrast Agents Delivery: An Up-to-Date Review of Nanodiagnostics in Neuroimaging

Neuroimaging is a highly important field of neuroscience, with direct implications for the early diagnosis and progression monitoring of brain-associated diseases. Neuroimaging techniques are categorized into structural, functional and molecular neuroimaging, each possessing advantages and disadvantages in terms of resolution, invasiveness, toxicity of contrast agents and costs. Nanotechnology-based approaches for neuroimaging mostly involve the development of nanocarriers for incorporating contrast agents or the use of nanomaterials as imaging agents. Inorganic and organic nanoparticles, liposomes, micelles, nanobodies and quantum dots are some of the most studied candidates for the delivery of contrast agents for neuroimaging. This paper focuses on describing the conventional modalities used for imaging and the applications of nanotechnology for developing novel strategies for neuroimaging. The aim is to highlight the roles of nanocarriers for enhancing and/or overcome the limitations associated with the most commonly utilized neuroimaging modalities. For future directions, several techniques that could benefit from the increased contrast induced by using imaging probes are presented.