Synergistically integrated nanoparticles as multimodal probes for nanobiotechnology

Gram-Scale Synthesis of Renal-Clearable Tantalum Nanodots with High Water Solubility for Computed Tomography Imaging In Vivo

Tantalum (Ta) emerges as a promising element for advanced computed tomography (CT) imaging probes owing to its high X-ray attenuation coefficient and excellent biocompatibility. Nevertheless, the synthesis of renally clear Ta-based imaging probes through simple methods remains a significant challenge. Herein, we introduce a simple and gram-scale approach for the synthesis of renal-clearable Ta nanodots with high water solubility for CT imaging in vivo. The Ta nanodots, coordination polymers, are fabricated via coordination reactions involving Ta(OH)5, citric acid (CA), and hydrogen peroxide. The Ta nanodots exhibit an ultrasmall hydrodynamic diameter (2.8 nm), high water solubility (1.88 g/mL, 688 mg Ta/mL), superior X-ray absorption capacity, gram-scale production capability (>10 g in lab synthesis), renal-clearable ability, and good biocompatibility. The Ta nanodots possess superior CT imaging efficacy across diverse tube voltages, enabling highly sensitive gastrointestinal CT imaging, renal CT imaging, and CT angiography (CTA). Moreover, Ta nanodots maintain robust CT imaging capabilities even at high X-ray energies, and Ta nanodots-based spectral CT achieves metallic artifacts-minimized CTA. The proposed Ta nanodots present substantial potential as a potent CT imaging probe for diagnosing various diseases.

Iodinated gadolinium-gold nanomaterial as a multimodal contrast agent for cartilage tissue imaging

Cartilage damage, a common cause of osteoarthritis, requires medical imaging for accurate diagnosis of pathological changes. However, current instruments can acquire limited imaging information due to sensitivity and resolution issues. Therefore, multimodal imaging is considered an alternative strategy to provide valuable images and analyzes from different perspectives. Among all biomaterials, gold nanomaterials not only exhibit outstanding benefits as drug carriers, in vitro diagnostics, and radiosensitizers, but are also widely used as contrast agents, particularly for tumors. However, their potential for imaging cartilage damage is rarely discussed. In this study, we developed a versatile iodinated gadolinium-gold nanomaterial, AuNC@BSA-Gd-I, and its radiolabeled derivative, AuNC@BSA-Gd-131I, for cartilage detection. With its small size, negative charge, and multimodal capacities, the probe can penetrate damaged cartilage and be detected or visualized by computed tomography, MRI, IVIS, and gamma counter. Additionally, the multimodal imaging potential of AuNC@BSA-Gd-I was compared to current multifunctional gold nanomaterials containing similar components, including anionic AuNC@BSA, AuNC@BSA-I, and AuNC@BSA-Gd as well as cationic AuNC@CBSA. Due to their high atomic numbers and fluorescent emission, AuNC@BSA nanomaterials could provide fundamental multifunctionality for imaging. By further modifying AuNC@BSA with additional imaging materials, their application could be extended to various types of medical imaging instruments. Nonetheless, our findings showed that each of the current nanomaterials exhibited excellent abilities for imaging cartilage with their predominant imaging modalities, but their versatility was not comparable to that of AuNC@BSA-Gd-I. Thus, AuNC@BSA-Gd-I could be served as a valuable tool in multimodal imaging strategies for cartilage assessment.

Current Challenges in Monitoring Low Contaminant Levels of Per- and Polyfluoroalkyl Substances in Water Matrices in the Field

The Environmental Protection Agency (EPA) of the United States recently released the first-ever federal regulation on per- and polyfluoroalkyl substances (PFASs) for drinking water. While this represents an important landmark, it also brings about compliance challenges to the stakeholders in the drinking water industry as well as concerns to the general public. In this work, we address some of the most important challenges associated with measuring low concentrations of PFASs in drinking water in the field in real drinking water matrices. First, we review the "continuous monitoring for compliance" process laid out by the EPA and some of the associated hurdles. The process requires measuring, with some frequency, low concentrations (e.g., below 2 ppt or 2 ng/L) of targeted PFASs, in the presence of many other co-contaminants and in various conditions. Currently, this task can only (and it is expected to) be accomplished using specific protocols that rely on expensive, specialized, and laboratory-scale instrumentation, which adds time and increases cost. To potentially reduce the burden, portable, high-fidelity, low-cost, real-time PFAS sensors are desirable; however, the path to commercialization of some of the most promising technologies is confronted with many challenges, as well, and they are still at infant stages. Here, we provide insights related to those challenges based on results from ab initio and machine learning studies. These challenges are mainly due to the large amount and diversity of PFAS molecules and their multifunctional behaviors that depend strongly on the conditions of the media. The impetus of this work is to present relevant and timely insights to researchers and developers to accelerate the development of suitable PFAS monitoring systems. In addition, this work attempts to provide water system stakeholders, technicians, and even regulators guidelines to improve their strategies, which could ultimately translate in better services to the public.

Near-infrared-II fluorescence/magnetic resonance double modal imaging of transplanted stem cells using lanthanide co-doped gadolinium oxide nanoparticles

To ensure maximum therapeutic safety and efficacy of stem cell transplantation, it is essential to observe the kinetics of behavior, accumulation, and engraftment of transplanted stem cells in vivo. However, it is difficult to detect transplanted stem cells with high sensitivity by conventional in vivo imaging technologies. To diagnose the kinetics of transplanted stem cells, we prepared multifunctional nanoparticles, Gd2O3 co-doped with Er3+ and Yb3+ (Gd2O3: Er, Yb-NPs), and developed an in vivo double modal imaging technique with near-infrared-II (NIR-II) fluorescence imaging and magnetic resonance imaging (MRI) of stem cells using Gd2O3: Er, Yb-NPs. Gd2O3: Er, Yb-NPs were transduced into adipose tissue-derived stem cells (ASCs) through a simple incubation process without cytotoxicity under certain concentrations of Gd2O3: Er, Yb-NPs and were found not to affect the morphology of ASCs. ASCs labeled with Gd2O3: Er, Yb-NPs were transplanted subcutaneously onto the backs of mice, and successfully imaged with good contrast using an in vivo NIR-II fluorescence imaging and MRI system. These data suggest that Gd2O3: Er, Yb-NPs may be useful for in vivo double modal imaging with NIR-II fluorescence imaging and MRI of transplanted stem cells.

Hybridized quantum dot, silica, and gold nanoparticles for targeted chemo-radiotherapy in colorectal cancer theranostics

Multimodal nanoparticles, utilizing quantum dots (QDs), mesoporous silica nanoparticles (MSNs), and gold nanoparticles (Au NPs), offer substantial potential as a smart and targeted drug delivery system for simultaneous cancer therapy and imaging. This method entails coating magnetic GZCIS/ZnS QDs with mesoporous silica, loading epirubicin into the pores, capping with Au NPs, PEGylation, and conjugating with epithelial cell adhesion molecule (EpCAM) aptamers to actively target colorectal cancer (CRC) cells. This study showcases the hybrid QD@MSN-EPI-Au-PEG-Apt nanocarriers (size ~65 nm) with comprehensive characterizations post-synthesis. In vitro studies demonstrate the selective cytotoxicity of these targeted nanocarriers towards HT-29 cells compared to CHO cells, leading to a significant reduction in HT-29 cell survival when combined with irradiation. Targeted delivery of nanocarriers in vivo is validated by enhanced anti-tumor effects with reduced side effects following chemo-radiotherapy, along with imaging in a CRC mouse model. This approach holds promise for improved CRC theranostics.

NSF evaluation of gadolinium biodistribution in renally impaired rats: Using novel metabolic Gd2O3 nanoparticles coated with β-cyclodextrin (Gd2O3@PCD) in MR molecular imaging

The use of conventional gadolinium(Gd)-based contrast agents in magnetic resonance imaging (MRI) poses a significant risk of Nephrogenic Systemic Fibrosis (NSF) syndrome in patients with impaired renal function (grades 4 and 5). To address this issue, a new study has introduced a novel metabolic Gadolinium oxide nanoparticle (Gd2O3 NPs) coated with β-cyclodextrin (βCD). The study aims to investigate NSF syndrome by quantifying tissue Gd deposition biodistribution in renal impairment rats using MR molecular imaging. This is the first study of its kind to use this approach. A group of 20 rats were divided into four groups, each containing five rats that underwent 5/6 nephrectomy. The rats received 12 intravenous injections of a novel homemade synthesized gadolinium oxide polycyclodextrin (Gd2O3@PCD) at a dose of 0.1 mmol/kg, conventional contrast agents (CAs) drugs of Omniscan (Gd-DTPA-BMA) and Dotarem (Gd-DOTA), at a dose of 2.5 mmol/kg, and 250 μl saline for two injections per week during six weeks. T1-weighted MR imaging was performed before the injections and once a week for six weeks to quantify Gd deposition in four different organs (skin, liver, heart, and lung) in rats using inductively coupled plasma mass spectrometry (ICP-MS). The relationship between Signal-to-Noise Ratio (SNR) and biodistribution of Gd deposition due to NSF-induced syndrome was also calculated. The results of the study showed that the Gd concentrations in tissues were significantly higher in the Gd2O3@PCD group compared to the other groups, without any significant histopathological changes (P < 0.05). In the Gd2O3@PCD group, Gd was mainly deposited in the skin, followed by the liver, lung, and heart, without any symptoms of thickening or hardening of the skin. The Gd concentrations in the skin, liver, lung, and heart were significantly lower in the Dotarem group than in the Omniscan group (P < 0.05). In the histopathological examinations, the Omniscan group showed increased cellularity in the dermis. A significant hyperintensity was observed in the Gd2O3@PCD-treated rats compared to the Dotarem and Omniscan groups in the liver, heart, and lung. Compared to conventional Gd-based CAs, the novel metabolically Gd2O3@PCD with increased SNR, biosafety, and a considerably lower probability of developing NSF, has potential applicability for diagnosing patients with renal diseases in clinical MR Molecular Imaging (MRMI).

Exploring the current landscape of chitosan-based hybrid nanoplatforms as cancer theragnostic

In the last decade, investigators have put significant efforts to develop several diagnostic and therapeutic strategies against cancer. Many novel nanoplatforms, including lipidic, metallic, and inorganic nanocarriers, have shown massive potential at preclinical and clinical stages for cancer diagnosis and treatment. Each of these nano-systems is distinct with its own benefits and limitations. The need to overcome the limitations of single-component nano-systems, improve their morphological and biological features, and achieve multiple functionalities has resulted in the emergence of hybrid nanoparticles (HNPs). These HNPs integrate multicomponent nano-systems with diagnostic and therapeutic functions into a single nano-system serving as promising nanotools for cancer theragnostic applications. Chitosan (CS) being a mucoadhesive, biodegradable, and biocompatible biopolymer, has emerged as an essential element for the development of HNPs offering several advantages over conventional nanoparticles including pH-dependent drug delivery, sustained drug release, and enhanced nanoparticle stability. In addition, the free protonable amino groups in the CS backbone offer flexibility to its structure, making it easy for the modification and functionalization of CS, resulting in better drug targetability and cell uptake. This review discusses in detail the existing different oncology-directed CS-based HNPs including their morphological characteristics, in-vitro/in-vivo outcomes, toxicity concerns, hurdles in clinical translation, and future prospects.

Advanced strategies for CRISPR/Cas9 delivery and applications in gene editing, therapy, and cancer detection using nanoparticles and nanocarriers

Cancer remains one of the deadliest diseases, and is characterised by the uncontrolled growth of modified human cells. Unlike infectious diseases, cancer does not originate from foreign agents. Though a variety of diagnostic procedures are available; their cost-effectiveness and accessibility create significant hurdles. Non-specific cancer symptoms further complicate early detection, leading to belated recognition of certain cancer. The lack of reliable biomarkers hampers effective treatment, as chemotherapy, radiation therapy, and surgery often result in poor outcomes and high recurrence rates. Genetic and epigenetic mutations play a crucial role in cancer pathogenesis, necessitating the development of alternate treatment methods. The advent of CRISPR/Cas9 technology has transformed molecular biology and exhibits potential for gene modification and therapy in various cancer types. Nonetheless, obstacles such as safe transport, off-target consequences, and potency must be overcome before widespread clinical use. Notably, this review delves into the multifaceted landscape of cancer research, highlighting the pivotal role of nanoparticles in advancing CRISPR/Cas9-based cancer interventions. By addressing the challenges associated with cancer diagnosis and treatment, this integrated approach paves the way for innovative solutions and improved patient outcomes.

Nanocrystals for Deep-Tissue In Vivo Luminescence Imaging in the Near-Infrared Region

In vivo imaging technologies have emerged as a powerful tool for both fundamental research and clinical practice. In particular, luminescence imaging in the tissue-transparent near-infrared (NIR, 700-1700 nm) region offers tremendous potential for visualizing biological architectures and pathophysiological events in living subjects with deep tissue penetration and high imaging contrast owing to the reduced light-tissue interactions of absorption, scattering, and autofluorescence. The distinctive quantum effects of nanocrystals have been harnessed to achieve exceptional photophysical properties, establishing them as a promising category of luminescent probes. In this comprehensive review, the interactions between light and biological tissues, as well as the advantages of NIR light for in vivo luminescence imaging, are initially elaborated. Subsequently, we focus on achieving deep tissue penetration and improved imaging contrast by optimizing the performance of nanocrystal fluorophores. The ingenious design strategies of NIR nanocrystal probes are discussed, along with their respective biomedical applications in versatile in vivo luminescence imaging modalities. Finally, thought-provoking reflections on the challenges and prospects for future clinical translation of nanocrystal-based in vivo luminescence imaging in the NIR region are wisely provided.

Redox-Activatable Magnetic Nanoarchitectonics for Self-Enhanced Tumor Imaging and Synergistic Photothermal-Chemodynamic Therapy

Oral squamous cell carcinoma (OSCC) is a prevalent malignancy of the head and neck region associated with high recurrence rates and poor prognosis under current diagnostic and treatment methods. The development of nanomaterials that can improve diagnostic accuracy and therapeutic efficacy is of great importance for OSCC. In this study, a redox-activatable nanoarchitectonics is designed via the construction of dual-valence cobalt oxide (DV-CO) nanospheres, which can serve as a contrast agent for magnetic resonance (MR) imaging, and exhibit enhanced transverse and longitudinal relaxivities through the release and redox of Co3+ /Co2+ in an acidic condition with glutathione (GSH), resulting in self-enhanced T1 /T2 -weighted MR contrast. Moreover, DV-CO demonstrates properties of intracellular GSH-depletion and hydroxyl radicals (•OH) generation through a Fenton-like reaction, enabling strengthened chemodynamic (CD) effect. Additionally, DV-CO displays efficient near-infrared laser-induced photothermal (PT) effect, thereby exhibiting synergistic PT-CD therapy for suppressing OSCC tumor cells. It further investigates the tumor-specific self-enhanced MR imaging of DV-CO both in subcutaneous and orthotopic OSCC mouse models, and demonstrate the therapeutic effects of DV-CO in orthotopic OSCC mouse models. Overall, the in vitro and in vivo findings highlight the excellent theranositc potentials of DV-CO for OSCC and offer new prospects for future advancement of nanomaterials.

Molecular imaging of tumour-associated pathological biomarkers with smart nanoprobe: From "Seeing" to "Measuring"

Although the extraordinary progress has been made in molecular biology, the prevention of cancer remains arduous. Most solid tumours exhibit both spatial and temporal heterogeneity, which is difficult to be mimicked in vitro. Additionally, the complex biochemical and immune features of tumour microenvironment significantly affect the tumour development. Molecular imaging aims at the exploitation of tumour-associated molecules as specific targets of customized molecular probe, thereby generating image contrast of tumour markers, and offering opportunities to non-invasively evaluate the pathological characteristics of tumours in vivo. Particularly, there are no "standard markers" as control in clinical imaging diagnosis of individuals, so the tumour pathological characteristics-responsive nanoprobe-based quantitative molecular imaging, which is able to visualize and determine the accurate content values of heterogeneous distribution of pathological molecules in solid tumours, can provide criteria for cancer diagnosis. In this context, a variety of "smart" quantitative molecular imaging nanoprobes have been designed, in order to provide feasible approaches to quantitatively visualize the tumour-associated pathological molecules in vivo. This review summarizes the recent achievements in the designs of these nanoprobes, and highlights the state-of-the-art technologies in quantitative imaging of tumour-associated pathological molecules.

Iron Nanoparticles Open Up New Directions for Promoting Healing in Chronic Wounds in the Context of Bacterial Infection

Metal nanoparticles play an outstanding role in the field of wound healing due to their excellent properties, and the significance of iron, one of the most widely used metals globally, cannot be overlooked. The purpose of this review is to determine the importance of iron nanoparticles in wound-healing dressings. Prolonged, poorly healing wounds may induce infections; wound infections are a major cause of chronic wound formation. The primary components of iron nanoparticles are iron oxide nanoparticles, which promote wound healing by being antibacterial, releasing metal ions, and overcoming bacterial resistance. The diameter of iron oxide nanoparticles typically ranges between 1 and 100 nm. Magnetic nanoparticles with a diameter of less than 30 nm are superparamagnetic and are referred to as superparamagnetic iron oxide nanoparticles. This subset of iron oxide nanoparticles can use an external magnetic field for novel functions such as magnetization and functionalization. Iron nanoparticles can serve clinical purposes not only to enhance wound healing through the aforementioned means but also to ameliorate anemia and glucose irregularities, capitalizing on iron's properties. Iron nanoparticles positively impact the healing process of chronic wounds, potentially extending beyond wound management.

Colorimetric and Label-Free Optical Detection of Pb2+ Ions via Colloidal Gold Nanoparticles

The detection of the lead heavy metal (Pb) in water is crucial in many chemical processes, as it is associated with serious health hazards. Here, we report the selective and precise colorimetric detection of Pb2+ ions in water, exploiting the aggregation and self-assembly mechanisms of glutathione (GSH)-functionalized gold nanoparticles (GNPs). The carboxyl functional groups are able to create coordination complexes with Pb2+, inducing aggregation amongst the GSH-GNPs in the presence of Pb2+ due to the chelation of the GSH ligands. The resulting aggregation amongst the GSH-GNPs in the presence of Pb2+ increases the aggregate size depending on the available Pb2+ ions, affecting the plasmonic coupling. This causes a substantial shift in the plasmon wavelength to a longer wavelength side with increasing Pb2+ concentration, resulting in a red-to-blue colorimetric or visual change, enabling the instant determination of lead content in water.

The Influence of Catechols on the Magnetization of Iron Oxide Nanoparticles

In this study, MNPs were functionalized with pyrocatechol (CAT), pyrogallol (GAL), caffeic acid (CAF), and nitrodopamine (NDA) at pH 8 and pH 11. The functionalization of the MNPs was successful, except in the case of NDA at pH 11. The thermogravimetric analyses indicated that the surface concentration of the catechols was between 1.5 and 3.6 molecules/nm². The saturation magnetizations (M_s) of the functionalized MNPs were higher than the starting material. XPS analyses showed only the presence of Fe(III) ions on the surface, thus refuting the idea of the Fe being reduced and magnetite being formed on the surfaces of the MNPs. Density functional theory (DFT) calculations were performed for two modes of adsorption of CAT onto two model surfaces: plain and adsorption via condensation. The total magnetization of both adsorption modes remained the same, indicating that the adsorption of the catechols does not affect the M_s. The analyses of the size and the size distribution showed an increase in the average size of the MNPs during the functionalization process. This increase in the average size of the MNPs and the reduction in the fraction of the smallest (i.e., <10 nm) MNPs explained the increase in the M_s values.

CD40-targeting magnetic nanoparticles for MRI/optical dual-modality molecular imaging of vulnerable atherosclerotic plaques

BACKGROUND AND AIMS

Acute coronary syndrome caused by vulnerable plaque rupture or erosion is a leading cause of death worldwide. CD40 has been reported to be highly expressed in atherosclerotic plaques and closely related to plaque stability. Therefore, CD40 is expected to be a potential target for the molecular imaging of vulnerable plaques in atherosclerosis. We aimed to design a CD40-targeted magnetic resonance imaging (MRI)/optical multimodal molecular imaging probe and explore its ability to detect and target vulnerable atherosclerotic plaques.

METHODS

CD40-Cy5.5 superparamagnetic iron oxide nanoparticles (CD40-Cy5.5-SPIONs), which comprise a CD40-targeting multimodal imaging contrast agent, were constructed by conjugating CD40 antibody and Cy5.5-N-hydroxysuccinimide ester with SPIONs. During this in vitro study, we observed the binding ability of CD40-Cy5.5-SPIONs with RAW 264.7 cells and mouse aortic vascular smooth muscle cells (MOVAS) after different treatments, using confocal fluorescence microscopy and Prussian blue staining. An in vivo study involving ApoE^-/- mice fed a high-fat diet for 24-28 weeks was performed. 24 h after intravenous injection of CD40-Cy5.5-SPIONs, fluorescence imaging and MRI were performed.

RESULTS

CD40-Cy5.5-SPIONs bind specifically to tumor necrosis factor (TNF)-α-treated macrophages and smooth muscle cells. Fluorescence imaging results showed that, compared with the control group and the atherosclerosis group injected with non-specific bovine serum albumin (BSA)-Cy5.5-SPIONs, the atherosclerotic group injected with CD40-Cy5.5-SPIONs had a stronger fluorescence signal. T2-weighted images showed that the carotid arteries of atherosclerotic mice injected with CD40-Cy5.5-SPIONs had a significant substantial T2 contrast enhancement effect.

CONCLUSIONS

CD40-Cy5.5-SPIONs could potentially serve as an effective MRI/optical probe for vulnerable atherosclerotic plaques during non-invasive detection.

Current advances in the application of nanomedicine in bladder cancer

Bladder cancer is the most common malignant tumor of the urinary system, however there are several shortcomings in current diagnostic and therapeutic measures. In terms of diagnosis, the diagnostic tools currently available are not sufficiently sensitive and specific, and imaging is poor, leading to misdiagnosis and missed diagnoses, which can delay treatment. In terms of treatment, current treatment options include surgery, chemotherapy, immunotherapy, gene therapy, and other emerging treatments, as well as combination therapies. However, the main reasons for poor efficacy and side effects during treatment are the lack of specificity and targeting, improper dose control of drugs and photosensitizers, damage to normal cells while attacking cancer cells, and difficulty in delivering siRNA to cancer cells. Nanomedicine is an emerging approach. Among the many nanotechnologies applied in the medical field, nanocarrier-assisted drug delivery systems have attracted extensive research interest due to their great translational value. Well-designed nanoparticles can deliver agents or drugs to specific cell types within target organs through active targeting or passive targeting (enhanced permeability and retention), which allows for imaging, diagnosis, as well as treatment of cancer. This paper reviews advances in the application of various nanocarriers and their advantages and drawbacks, with a focus on their use in the diagnosis and treatment of bladder cancer.

Medical Imaging Technology and Imaging Agents

Medical imaging is a technology that studies the interaction between human body and irradiations of X-ray, ultrasound, magnetic field, etc. and represents anatomical structures of human organs/tissues with the implication of irradiation attenuation in the form of grayscales. With these medical images, detailed information on health status and disease diagnosis may be judged by clinical physicians to determine an appropriate therapy approach. This chapter will give a systematic introduction on the modalities, classifications, basic principles, and biomedical applications of traditional medical imaging along with the types, construction, and major features of the corresponding contrast agents or imaging probes.

Emerging Biomaterials Imaging Antitumor Immune Response

Immunotherapy is one of the most promising clinical modalities for the treatment of malignant tumors and has shown excellent therapeutic outcomes in clinical settings. However, it continues to face several challenges, including long treatment cycles, high costs, immune-related adverse events, and low response rates. Thus, it is critical to predict the response rate to immunotherapy by using imaging technology in the preoperative and intraoperative. Here, the latest advances in nanosystem-based biomaterials used for predicting responses to immunotherapy via the imaging of immune cells and signaling molecules in the immune microenvironment are comprehensively summarized. Several imaging methods, such as fluorescence imaging, magnetic resonance imaging, positron emission tomography imaging, ultrasound imaging, and photoacoustic imaging, used in immune predictive imaging, are discussed to show the potential of nanosystems for distinguishing immunotherapy responders from nonresponders. Nanosystem-based biomaterials aided by various imaging technologies are expected to enable the effective prediction and diagnosis in cases of tumors, inflammation, and other public diseases.

Amalgamation of Nanoparticles within Drug Carriers: A Synergistic Approach or a Futile Attempt?

In recent years, nanotechnology has gained much attention from scientists and significant advances in therapeutic potential. Nano-delivery systems have emerged as an effective way in order to improve the therapeutic properties of drugs including solubility, stability, prolongation of half-life as well as promoting the accumulation of drug at the target site. The nanoparticles have also been incorporated into various conventional drug delivery systems. This review study aims to introduce the amalgamation of nanoparticles into drug carriers. To overcome the limitations of single nanoparticles such as toxicity, high instability, rapid drug release as well as limited drug loading capacity, a multi-component system is developed. Liposomes, microparticles, nanofibers, dendrimers etc., are promising drug carriers, having some limitations that can be minimized, and the compilation of nanoparticles synergizes the properties. The amalgamated nanocarriers are used for the diagnostic purpose as well as treatment of various chronic diseases. It also increases the solubility of hydrophobic drugs. However, each system has its advantages and disadvantages based on its physicochemical properties, efficacy, and other parameters. This review details the past and present state of development for the fusion of nanoparticles within drug carriers and from which we identify future research works needed for the same.

Industrialization’s eye view on theranostic nanomedicine

The emergence of nanomedicines (NMs) in the healthcare industry will bring about groundbreaking improvements to the current therapeutic and diagnostic scenario. However, only a few NMs have been developed into clinical applications due to a lack of regulatory experience with them. In this article, we introduce the types of NM that have the potential for clinical translation, including theranostics, multistep NMs, multitherapy NMs, and nanoclusters. We then present the clinical translational challenges associated with NM from the pharmaceutical industry’s perspective, such as NMs’ intrinsic physiochemical properties, safety, scale-up, lack of regulatory experience and standard characterization methods, and cost-effectiveness compared with their traditional counterparts. Overall, NMs face a difficult task to overcome these challenges for their transition from bench to clinical use.

Nanoarchitectonics horizons: materials for life sciences

Nanoarchitectonics relies on the fabrication of materials at the atomic/molecular level to achieve the desired shape and function. Significant advances have been made in understanding the characteristics and spatial assemblies that contribute to material performance. Biomaterials undergo several changes when presented with various environmental cues. The ability to overcome such challenges, maintaining the integrity and effective functioning of native properties, can be regarded as a characteristic of a successful biomaterial. Control over the shape and efficacy of target materials can be tailored via various processes, like self-assembly, supramolecular chemistry, atomic/molecular manipulation, etc. Interplay between the physicochemical properties of materials and biomolecule recognition sites defines the structural rigidity in hierarchical structures. Materials including polymers, metal nanoparticles, nucleic acid systems, metal-organic frameworks, and carbon-based nanostructures can be viewed as promising prospects for developing biocompatible systems. This review discusses recent advances relating to such biomaterials for life science applications, where nanoarchitectonics plays a decisive role either directly or indirectly.

In Vivo Multimodal Imaging of Stem Cells Using Nanohybrid Particles Incorporating Quantum Dots and Magnetic Nanoparticles

The diagnosis of the dynamics, accumulation, and engraftment of transplanted stem cells in vivo is essential for ensuring the safety and the maximum therapeutic effect of regenerative medicine. However, in vivo imaging technologies for detecting transplanted stem cells are not sufficient at present. We developed nanohybrid particles composed of dendron-baring lipids having two unsaturated bonds (DLU2) molecules, quantum dots (QDs), and magnetic nanoparticles in order to diagnose the dynamics, accumulation, and engraftment of transplanted stem cells, and then addressed the labeling and in vivo fluorescence and magnetic resonance (MR) imaging of stem cells using the nanohybrid particles (DLU2-NPs). Five kinds of DLU2-NPs (DLU2-NPs-1-5) composed of different concentrations of DLU2 molecules, QDs525, QDs605, QDs705, and ATDM were prepared. Adipose tissue-derived stem cells (ASCs) were labeled with DLU2-NPs for 4 h incubation, no cytotoxicity or marked effect on the proliferation ability was observed in ASCs labeled with DLU2-NPs (640- or 320-fold diluted). ASCs labeled with DLU2-NPs (640-fold diluted) were transplanted subcutaneously onto the backs of mice, and the labeled ASCs could be imaged with good contrast using in vivo fluorescence and an MR imaging system. DLU2-NPs may be useful for in vivo multimodal imaging of transplanted stem cells.

Solid-State Reaction Synthesis of Nanoscale Materials: Strategies and Applications

Nanomaterials (NMs) with unique structures and compositions can give rise to exotic physicochemical properties and applications. Despite the advancement in solution-based methods, scalable access to a wide range of crystal phases and intricate compositions is still challenging. Solid-state reaction (SSR) syntheses have high potential owing to their flexibility toward multielemental phases under feasibly high temperatures and solvent-free conditions as well as their scalability and simplicity. Controlling the nanoscale features through SSRs demands a strategic nanospace-confinement approach due to the risk of heat-induced reshaping and sintering. Here, we describe advanced SSR strategies for NM synthesis, focusing on mechanistic insights, novel nanoscale phenomena, and underlying principles using a series of examples under different categories. After introducing the history of classical SSRs, key theories, and definitions central to the topic, we categorize various modern SSR strategies based on the surrounding solid-state media used for nanostructure growth, conversion, and migration under nanospace or dimensional confinement. This comprehensive review will advance the quest for new materials design, synthesis, and applications.

Harmful Microalgae Detection: Biosensors versus Some Conventional Methods

In the last decade, there has been a steady stream of information on the methods and techniques available for detecting harmful algae species. The conventional approaches to identify harmful algal bloom (HAB), such as microscopy and molecular biological methods are mainly laboratory-based and require long assay times, skilled manpower, and pre-enrichment of samples involving various pre-experimental preparations. As an alternative, biosensors with a simple and rapid detection strategy could be an improvement over conventional methods for the detection of toxic algae species. Moreover, recent biosensors that involve the use of nanomaterials to detect HAB are showing further enhanced detection limits with a broader linear range. The improvement is attributed to nanomaterials' high surface area to volume ratio, excellent biological compatibility with biomolecules, and being capable of amplifying the electrochemical signal. Hence, this review presents the potential usage of biosensors over conventional methods to detect HABs. The methods reported for the detection of harmful algae species, ranging from conventional detection methods to current biosensor approaches will be discussed, along with their respective advantages and drawbacks to indicate the future prospects of biosensor technology for HAB event management.

Dual-Labelling Strategies for Nuclear and Fluorescence Molecular Imaging: Current Status and Future Perspectives

Molecular imaging offers the possibility to investigate biological and biochemical processes non-invasively and to obtain information on both anatomy and dysfunctions. Based on the data obtained, a fundamental understanding of various disease processes can be derived and treatment strategies can be planned. In this context, methods that combine several modalities in one probe are increasingly being used. Due to the comparably high sensitivity and provided complementary information, the combination of nuclear and optical probes has taken on a special significance. In this review article, dual-labelled systems for bimodal nuclear and optical imaging based on both modular ligands and nanomaterials are discussed. Particular attention is paid to radiometal-labelled molecules for single-photon emission computed tomography (SPECT) and positron emission tomography (PET) and metal complexes combined with fluorescent dyes for optical imaging. The clinical potential of such probes, especially for fluorescence-guided surgery, is assessed.

Engineered lanthanide-doped upconversion nanoparticles for biosensing and bioimaging application

Various fluctuations of intracellular ions, biomolecules, and other conditions in the physiological environment play crucial roles in fundamental biological processes. These factors are of great importance for analysis in biomedical detection. Nevertheless, developments of the simple, rapid, and accurate proof for specific detection still encounter major challenges. Upconversion nanoparticles (UCNPs), which could absorb multiple low-energy near-infrared light (NIR) photon excitation and emits high-energy photons caused by anti-Stokes shift, show unique upconversion luminescence (UCL) properties, for example, sharp emission band, high physicochemical stability like near-zero photobleaching, photo blinking in biological tissues, and long luminescence lifetime. Furthermore, the NIR used for the light source to excite UCNPs enable lower photo-damage effect and deeper penetration of tissue, and in the meantime, it can avoid the auto-fluorescence and light scattering from biological tissue interference. Thus, the lanthanide-doped UCNP-based functional platform with controlled structure, crystalline phase, size, and multicolor emission has become an appropriate nanomaterial for bioapplications such as biosensing, bioimaging, drug release, and therapies. In this review, the recent progress about synthesis and biomedical applications of UCNPs related to sensing and bioimaging is summarized. Firstly, the different luminescence mechanisms of the upconversion process are presented. Secondly, four of the most common methods for synthesizing UCNPs are compared as well as the advantages and disadvantages of these synthetic routes. Meanwhile, the surface modification of lanthanide-doped UCNPs was introduced to pave the way for their biochemistry applications. Next, this review detailed the biological applications of lanthanide-doped UCNPs, particularly in bioimaging, including UCL and multi-modal imaging and biosensing (monitoring intracellular ions and biomolecules). Finally, the challenges and future perspectives in materials science and biomedical fields of UCNPs are concluded: the low quantum yield of the upconversion process should be considered when they are executed as imaging contrast agents. And the biosafety of lanthanide-doped UCNPs needs to be evaluated.

ES-MION-Based Dual-Modality PET/MRI Probes for Acidic Tumor Microenvironment Imaging

Among all characteristics of the tumor microenvironment (TME), which are caused by abnormal proliferation of solid tumors, extracellular acidity is an important indicator for malignancy grading. pH-low insertion peptides (pHLIPs) are adopted to discern the acidic TME. To date, different imaging agents including fluorescent, positron emission tomography (PET), single photon emission computed tomography (SPECT), and magnetic resonance (MR) contrast agents with pHLIPs to target the acidic TME have been used to image various tumor models successfully. In this article, a PET/MRI dual-modality probe, based on extremely small magnetic iron oxide nanoparticles (ES-MIONs) with pHLIPs as a targeting unit, was proposed for the first time. In the phantom study, the probe showed relatively high r 1 relaxivity (r 1 = 1.03 mM-1 s-1), indicating that it could be used as a T1-weighted MR contrast agent. The 68Ga-radiolabeled probe was further studied in vitro and in vivo to evaluate pHLIP targeting efficacy and feasibility for PET/MRI. PET with intratumoral injection and T1-weighted MRI with intravenous injection both showed pHLIP-specific delivery of the probe. Therefore, we successfully designed and developed a radiolabeled ES-MION-based dual-modality PET/MRI agent to target the acidic tumor microenvironment. Although the accumulation of the probe in tumors with intravenous injection was not high enough to exhibit signals in the PET imaging study, our study still provides further insights into the ES-MION-based PET/MRI strategy.

Sentinel lymph node detection by combining nonradioactive techniques with contrast agents: State of the art and prospects

The status of sentinel lymph nodes (SLNs) has a substantial prognostic value because these nodes are the first place where cancer cells accumulate along their spreading route. Routine SLN biopsy ("gold standard") involves peritumoral injections of radiopharmaceuticals, such as technetium-99m, which has obvious disadvantages. This review examines the methods used as "gold standard" analogs to diagnose SLNs. Nonradioactive preoperative and intraoperative methods of SLN detection are analyzed. Promising photonic tools for SLNs detection are reviewed, including NIR-I/NIR-II fluorescence imaging, photoswitching dyes for SLN detection, in vivo photoacoustic detection, imaging and biopsy of SLNs. Also are discussed methods of SLN detection by magnetic resonance imaging, ultrasonic imaging systems including as combined with photoacoustic imaging, and methods based on the magnetometer-aided detection of superparamagnetic nanoparticles. The advantages and disadvantages of nonradioactive SLN-detection methods are shown. The review concludes with prospects for the use of conservative diagnostic methods in combination with photonic tools.

Recent Advances in the Development and Applications of Conjugated Polymer dots

Conjugated polymer dots or semiconducting polymer nanoparticles (Pdots) are nanoparticles prepared based on organic polymers. Pdots have the advantages of lower cost, simple preparation process, good biocompatibility, excellent stability, easy...

Radionanomedicine: Advanced Strategy for Precision Theranostics of Breast Cancer

Breast carcinoma remains one of the most common and fatal cancers, and even though a series of general therapeutic approaches have been used to treat breast cancer, their outcomes are significantly affected by a variety of side effects. However, nanomedicine could offer novel strategies for dealing with breast carcinoma. In fact, an increasing number of radionanomedicine approaches have recently been used in both diagnostics and therapy. To highlight this trend, the aim of the current review is to systemically summarize the latest advances in radionanomedicine, including single-modular imaging, multiple-modular imaging, and nanomedicine-based theranostics. Barriers to clinical application, the development of next-generation radionanomedicine, and challenges associated with future design are also discussed.

Magnetic Nanoparticles: Synthesis, Anisotropy, and Applications

Anisotropy is an important and widely present characteristic of materials that provides desired direction-dependent properties. In particular, the introduction of anisotropy into magnetic nanoparticles (MNPs) has become an effective method to obtain new characteristics and functions that are critical for many applications. In this review, we first discuss anisotropy-dependent ferromagnetic properties, ranging from intrinsic magnetocrystalline anisotropy to extrinsic shape and surface anisotropy, and their effects on the magnetic properties. We further summarize the syntheses of monodisperse MNPs with the desired control over the NP dimensions, shapes, compositions, and structures. These controlled syntheses of MNPs allow their magnetism to be finely tuned for many applications. We discuss the potential applications of these MNPs in biomedicine, magnetic recording, magnetotransport, permanent magnets, and catalysis.

Polymers for Improved Delivery of Iodinated Contrast Agents

X-ray computed tomography (CT), as one of the most widely used noninvasive imaging modalities, can provide three-dimensional anatomic details with high resolution, which plays a key role in disease diagnosis and treatment assessment. However, although they are the most prevalent and FDA-approved contrast agents, iodinated water-soluble molecules still face some challenges in clinical applications, such as fast clearance, serious adverse effects, nonspecific distribution, and low sensitivity. Because of their high biocompatibility, tunable designability, controllable biodegradation, facile synthesis, and modification capability, the polymers have demonstrated great potential for efficient delivery of iodinated contrast agents (ICAs). Herein, we comprehensively summarized the applications of multifunctional polymeric materials for ICA delivery in terms of increasing circulation time, decreasing nephrotoxicity, and improving the specificity and sensitivity of ICAs for CT imaging. We mainly focused on various iodinated polymers from the aspects of preparation, functionalization, and application in medical diagnosis. Future perspectives for achieving better imaging and clinical translation are also discussed to motivate new technologies and solutions.

Imaging Strategy that Achieves Ultrahigh Contrast by Utilizing Differential Esterase Activity in Organs: Application in Early Detection of Pancreatic Cancer

Most nanoparticles show much higher uptake in mononuclear phagocyte system (MPS) organs than in tumors, which has been a long-lasting dilemma in nanomedicine. Here, we report an imaging strategy that selectively decreases MPS organ uptakes by utilizing the differential esterase activity in tumors and other organs. When an esterase-labile radiotracer loaded liposome was injected into the body, radioactivity was rapidly excreted from the liver and spleen after breakage of the ester bond by esterase. However, the lipophilic radiotracer delivered to the tumor remained in the tumor with minimal bond cleavage. The underlying mechanism was fully characterized in vitro and in vivo in colon tumor models. As a proof of concept, the liposomal radiotracer was further optimized for the early detection of pancreatic cancer. The folate-coated liposomal radiotracer showed highly selective tumor uptake. At 4 h postinjection, a pancreatic tumor a few millimeters in size was unambiguously visualized in orthotopic tumor models by PET imaging. At 24 h, an exceptionally high tumor-to-background ratio was achieved, enabling the visualization of tumors alone with minimal background noise. More than 9% of the total radioactivity was found in the tumor. Utilizing our imaging strategy, various tumor imaging agents can be developed for sensitive detection with ultrahigh contrast.

19 F MRI Probes for Multimodal Imaging*

Magnetic resonance imaging (MRI) is one of the most powerful imaging tools today, capable of displaying superior soft-tissue contrast. This review discusses developments in the field of ¹⁹ F MRI multimodal probes in combination with optical fluorescence imaging (OFI), ¹ H MRI, chemical exchange saturation transfer (CEST) MRI, ultrasonography (USG), X-ray computed tomography (CT), single photon emission tomography (SPECT), positron emission tomography (PET), and photoacoustic imaging (PAI). In each case, multimodal ¹⁹ F MRI probes compensate for the deficiency of individual techniques and offer improved sensitivity or accuracy of detection over unimodal counterparts. Strategies for designing ¹⁹ F MRI multimodal probes are described with respect to their structure, physicochemical properties, biocompatibility, and the quality of images.

Luminescent copper indium sulfide (CIS) quantum dots for bioimaging applications

Copper indium sulfide (CIS) quantum dots are ideal for bioimaging applications, by being characterized by high molar absorption coefficients throughout the entire visible spectrum, high photoluminescence quantum yield, high tolerance to the presence of lattice defects, emission tunability from the red to the near-infrared spectral region by changing their dimensions and composition, and long lifetimes (hundreds of nanoseconds) enabling time-gated detection to increase signal-to-noise ratio. The present review collects: (i) the most common procedures used to synthesize stable CIS QDs and the possible strategies to enhance their colloidal stability in aqueous environment, a property needed for bioimaging applications; (ii) their photophysical properties and parameters that affect the energy and brightness of their photoluminescence; (iii) toxicity and bioimaging applications of CIS QDs, including tumor targeting, time-gated detection and multimodal imaging, as well as theranostics. Future perspectives are analyzed in view of advantages and potential limitations of CIS QDs compared to most traditional QDs.

Comparative Toxicity, Biodistribution and Excretion of Ultra-Small Gold Nanoclusters with Different Emission Wavelengths

The exponentially increased use of gold nanoclusters in diagnosis and treatment has raised serious concern about their potential threat to living organisms. However, the mechanisms of toxicity of gold nanoclusters in vitro and in vivo remain poorly understood. In this work, comparative toxicity studies, including biodistribution and excretion, were carried out with mildly and chemically synthesized ultra-small L-histidine-protected and bovine serum albumin (BSA)-protected gold nanoclusters in an all-aqueous process. These nanoclusters did not induce a remarkable impact on cell viability, even at relatively high concentrations (100 μg/mL). The haemolytic assay demonstrated that the gold nanoclusters could not destroy blood cell at 600 μg/mL. After intravenous injection with mice, the biocompatibility, biodistribution, and excretion were determined. Quantitative analysis results showed that accumulation varied in the liver, spleen, kidney, and lung, though primarily in the liver and spleen. They were excreted in urine and faeces, but mainly excreted through urine. In our study, no obvious abnormalities were found in body weight, behavioral changes, blood and serum biochemical indicators, and histopathology. These findings suggested that both gold nanoclusters showed similar effects in vivo and were safe and biocompatible, laying the foundation for safe biomedical application in the future.

Biocompatible dextran-coated gadolinium-doped cerium oxide nanoparticles as MRI contrast agents with high T1 relaxivity and selective cytotoxicity to cancer cells

Gd-based complexes are widely used as magnetic resonance imaging (MRI) contrast agents. The safety of previously approved contrast agents is questionable and is being re-assessed. The main causes of concern are possible gadolinium deposition in the brain and the development of systemic nephrogenic fibrosis after repeated use of MRI contrasts. Thus, there is an urgent need to develop a new generation of MRI contrasts that are safe and that have high selectivity in tissue accumulation with improved local contrast. Here, we report on a new type of theranostic MRI contrast, namely dextran stabilised, gadolinium doped cerium dioxide nanoparticles. These ultra-small (4-6 nm) Ce_0.9Gd_0.1O_1.95 nanoparticles have been shown to possess excellent colloidal stability and high r₁-relaxivity (3.6 mM^-1 s^-1). They are effectively internalised by human normal and cancer cells and demonstrate dose-dependent selective cytotoxicity to cancer cells.

Synthesis of Magnetic Ions-Doped QDs Synthesized Via a Facial Aqueous Solution Method for Optical/MR Dual-Modality Imaging Applications

This research reports the preparation and examination of Cadmium Telluride (CdTe) Quantum Dots and doping CdTe QDs with Europium (Eu), Gadolinium (Gd), and Manganese (Mn) prepared in aqueous solution using TGA as a capping agent. Magnetic QDs (MQDs) are important agents for fluorescence (FL) /magnetic resonance (MR) dual-modal imaging due to their excellent optical and magnetic properties. Herein, the chemical bonds, structural, fluorescence, and magnetized properties of CdTe QDs and effect of Mn, Eu, and Gd ions doping on their properties were examined by X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTM), Energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared spectroscopy (FTIR), photoluminescence spectroscopy (PL), Ultraviolet-visible spectroscopy (UV-Vis), and vibrating sample magnetometer measurements (VSM). Almost similar X-Ray patterns with the absence/presence of ions for all samples with cubic crystal structures were obtained which indicated that the introduction of ions into CdTe QDs could not alter the cubic primary structure of CdTe. Monodisperse size distributed with seemingly-spherical shapes, and also, the estimated mean diameters about 3 and less than 3 nm of QDs were obtained. The effect of X ions injection on the fluorescence and UV-Vis properties of the QDs were also investigated. Optical studies showed the decreases in bandgap as the heating time increases during synthesis while undergoing red-shift. The CdTe nanocrystals with high PL quantum yields were achieved in more than 6 h of heating. Also, investigations have shown the quenching of fluorescence by the existence of ions in the CdTe QDs. Then, all the ions doped QDs exhibited ferromagnetic behavior at room temperature by a vibrating sample magnetometer which confirmed the success of the presentation of ions into CdTe cubic crystal structure. They can have been employed as a suitable contrast agent successfully for biological applications such as FL/MR dual-modal imaging.

Manipulation of Interfacial Diffusion for Controlling Nanoscale Transformation

The unprecedented development of inorganic nanostructure synthesis has paved the way toward their broad applications in areas such as food science, agroforestry, energy conversion, and biomedicine. The precise manipulation of the nucleation and subsequent growth has been recognized as the central guiding principle for controlling the size and morphology of the nanostructures. However, conventional colloid syntheses based on direct precipitation reactions still have limitations in their versatility and extendibility. The crystal structure of a material determines the limited number of possible morphologies that its nanostructures can adopt. Further, as nucleation and growth kinetics are sensitive to not only the nature of the precipitation reactions but also ligands and ripening effect, rigorous control of reaction conditions must be established for every specific synthesis. In addition, multiple experimental parameters are entangled with each other, thereby requiring rigorous control of all reaction conditions. As a result, it is usually challenging to extend a synthetic recipe from one material to another. As an alternative method, the direct transformation of existing nanostructures into target ones has become an effective and robust approach capable of creating various complex nanostructures that are otherwise challenging to obtain using conventional methods. To this end, an in-depth understanding of nanoscale transformation toward the synthesis of inorganic nanostructures with diverse properties and applications is highly desirable.In this Account, we aim to reveal the critical effect of the interfacial diffusion on controlled nanoscale transformation. We first discuss how the interdiffusion rates determine the morphology and properties of bimetallic nanostructures. While equal interdiffusion rates lead to perfect mixing and generate fully alloyed nanostructures, interdiffusion at unequal rates creates vacancies in the fast diffusion side, which may cause dramatic morphological transformation to the nanostructures. Then, we introduce interfacial reactions, including the Kirkendall cavitation process, elimination reaction, and solid-state reaction, to promote the unbalanced interdiffusion and generalize nanoscale transformations in materials of various compositions, morphologies, and crystal structures. Finally, we discuss the use of capping ligands to inhibit the diffusion of atoms on one side of the interface in order to enable selective etching or transformation of the nanostructures. By modifying the nanostructured surface with specific capping ligands, the diffusion of surface atoms is restricted. When nanoparticles undergo chemical reactions (such as etching or heating), the outward diffusion of substances dominates, thereby successfully achieving chemical and morphological transformations. We believe that controlled interfacial diffusion can effectively manipulate nanoscale transformations, thus providing new strategies for the custom synthesis of multifunctional nanomaterials for various specific applications.

Metal-Free Organo-Theranostic Nanosystem with High Nitroxide Stability and Loading for Image-Guided Targeted Tumor Therapy

The desire for all-organic-composed nanoparticles (NPs) of considerable biocompatibility to simultaneously diagnose and treat cancer is undeniably interminable. Heretofore, metal-based agents dominate the landscape of available magnetic resonance imaging (MRI) contrast agents and photothermal therapeutic agents, but with associated metal-specific downsides. Here, an all-organic metal-free nanoprobe, whose appreciable biocompatibility is synergistically contributed by its tetra-organo-components, is developed as a viable alternative to metal-based probes for MRI-guided tumor-targeted photothermal therapy (PTT). This rationally entails a glycol chitosan (GC)-linked polypyrrole (PP) nanoscaffold that provides abundant primary and secondary amino groups for amidation with the carboxyl groups in a nitroxide radical (TEMPO) and folic acid (FA), to obtain GC-PP@TEMPO-FA NPs. Advantageously, the appreciably benign GC-PP@TEMPO-FA features high nitroxide loading (r₁ = 1.58 mM^-1 s^-1) and in vivo nitroxide-reduction resistance, prolonged nitroxide-systemic circulation times, appreciable water dispersibility, potential photodynamic therapeutic and electron paramagnetic resonance imaging capabilities, considerable biocompatibility, and ultimately achieves a 17 h commensurate MRI contrast enhancement. Moreover, its GC component conveys a plethora of PP to tumor sites, where FA-mediated tumor targeting enables substantial NP accumulation with consequential near-complete tumor regression within 16 days in an MRI-guided PTT. The present work therefore promotes the engineering of organic-based metal-free biocompatible NPs in synergism, in furtherance of tumor-targeted image-guided therapy.

Harnessing Endogenous Stimuli for Responsive Materials in Theranostics

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.

Design and Synthesis of Luminescent Lanthanide-Based Bimodal Nanoprobes for Dual Magnetic Resonance (MR) and Optical Imaging

Current biomedical imaging techniques are crucial for the diagnosis of various diseases. Each imaging technique uses specific probes that, although each one has its own merits, do not encompass all the functionalities required for comprehensive imaging (sensitivity, non-invasiveness, etc.). Bimodal imaging methods are therefore rapidly becoming an important topic in advanced healthcare. This bimodality can be achieved by successive image acquisitions involving different and independent probes, one for each mode, with the risk of artifacts. It can be also achieved simultaneously by using a single probe combining a complete set of physical and chemical characteristics, in order to record complementary views of the same biological object at the same time. In this scenario, and focusing on bimodal magnetic resonance imaging (MRI) and optical imaging (OI), probes can be engineered by the attachment, more or less covalently, of a contrast agent (CA) to an organic or inorganic dye, or by designing single objects containing both the optical emitter and MRI-active dipole. If in the first type of system, there is frequent concern that at some point the dye may dissociate from the magnetic dipole, it may not in the second type. This review aims to present a summary of current activity relating to this kind of dual probes, with a special emphasis on lanthanide-based luminescent nano-objects.

Apoferritin Amyloid-Fibril Directed the In Situ Assembly and/or Synthesis of Optical and Magnetic Nanoparticles

The coupling of proteins that can assemble, recognise or mineralise specific inorganic species is a promising strategy for the synthesis of nanoscale materials with a controllable morphology and functionality. Herein, we report that apoferritin protein amyloid fibrils (APO) have the ability to assemble and/or synthesise various metal and metal compound nanoparticles (NPs). As such, we prepared metal NP-protein hybrid bioconjugates with improved optical and magnetic properties by coupling diverse gold (AuNPs) and magnetic iron oxide nanoparticles (MNPs) to apoferritin amyloid fibrils and compared them to the well-known β-lactoglobulin (BLG) protein. In a second approach, we used of solvent-exposed metal-binding residues in APO amyloid fibrils as nanoreactors for the in situ synthesis of gold, silver (AgNPs) and palladium nanoparticles (PdNPs). Our results demonstrate, the versatile nature of the APO biotemplate and its high potential for preparing functional hybrid bionanomaterials. Specifically, the use of apoferritin fibrils as vectors to integrate magnetic MNPs or AuNPs is a promising synthetic strategy for the preparation of specific contrast agents for early in vivo detection using various bioimaging techniques.

Functional Hybrid Molecules for the Visualization of Cancer: PESIN-Homodimers Combined with Multimodal Molecular Imaging Probes for Positron Emission Tomography and Optical Imaging: Suited for Tracking of GRPR-Positive Malignant Tissue*

We describe multimodal imaging probes for gastrin-releasing peptide receptor (GRPR)-specific targeting suited for positron emission tomography and optical imaging (PET/OI), consisting of PESIN (PEG3 -BBN7-14 ) dimers connected to multimodal imaging subunits. These multimodal agents comprise a fluorescent dye for OI and the chelator ((1,4,7-triazacyclononane-4,7-diyl)diacetic acid-1-glutaric acid) (NODA-GA) for PET radiometal isotope labelling. Special focus was put on the influence of the used dyes on the properties of the whole bioconjugates. For this, several compounds with different fluorescent dyes and non-dye carrying subunits were synthesized and investigated. As fluorescent dyes, dansyl, NBD, derivatives of fluorescein, coumarin and rhodamine as well as three pyrilium-based dyes were employed. Considerable influence of the charge of the colored unit on hydrophilicity as well as in vitro target receptor binding was observed and classified. High radiochemical yields and purities were found during radiolabeling of the multimodal imaging subunits as well as their GRPR-specific bioconjugates with 68 Ga. Examinations of the photophysical properties of both molecule species displayed no loss or alteration of fluorescence characteristics.