Effects of nanoparticle size on cellular uptake and liver MRI with polyvinylpyrrolidone-coated iron oxide nanoparticles

Inorganic Nanoparticle Functionalization Strategies in Immunotherapeutic Applications

Nanotechnology has been increasingly utilized in anticancer treatment owing to its ability of engineering functional nanocarriers that enhance therapeutic effectiveness while minimizing adverse effects. Inorganic nanoparticles (INPs) are prevalent nanocarriers to be customized for a wide range of anticancer applications, including theranostics, imaging, targeted drug delivery, and therapeutics, because they are advantageous for their superior biocompatibility, unique optical properties, and capacity of being modified via versatile surface functionalization strategies. In the past decades, the high adaptation of INPs in this emerging immunotherapeutic field makes them good carrier options for tumor immunotherapy and combination immunotherapy. Tumor immunotherapy requires targeted delivery of immunomodulating therapeutics to tumor locations or immunological organs to provoke immune cells and induce tumor-specific immune response while regulating immune homeostasis, particularly switching the tumor immunosuppressive microenvironment. This review explores various INP designs and formulations, and their employment in tumor immunotherapy and combination immunotherapy. We also introduce detailed demonstrations of utilizing surface engineering tactics to create multifunctional INPs. The generated INPs demonstrate the abilities of stimulating and enhancing the immune response, specific targeting, and regulating cancer cells, immune cells, and their resident microenvironment, sometimes along with imaging and tracking capabilities, implying their potential in multitasking immunotherapy. Furthermore, we discuss the promises of INP-based combination immunotherapy in tumor treatments.

Antitumor Activity and Mechanistic Insights of a Mitochondria-Targeting Cu(I) Complex

Using copper-ionophores to translocate extracellular copper into mitochondria is a clinically validated anticancer strategy that has been identified as a new type of regulated cell death termed "cuproptosis." This study reports a mitochondria-targeting Cu(I) complex, Cu(I)Br(PPh3)3 (CBP), consisting of a cuprous ion coordinated by three triphenylphosphine moieties and a Br atom. CBP exhibited antitumor and antimetastatic efficacy in vitro and in vivo by specifically targeting mitochondria instigating mitochondrial dysfunction. The cytotoxicity of CBP could only be reversed by a copper chelator rather than inhibitors of the known cell death, indicating copper-dependent cytotoxicity. Furthermore, CBP induced the oligomerization of lipoylated proteins and the loss of Fe-S cluster proteins, consistent with characteristic features of cuproptosis. Additionally, CBP induced remarkable intracellular generation of reactive oxygen species (ROS) through a Fenton-like reaction, indicating a complex antitumor mechanism. This is a proof-of-concept study exploiting the antitumor activity and mechanism of the Cu(I)-based mitochondria-targeting therapy.

Ultrasmall catechol-PEG-anchored ferrite nanoparticles for highly sensitive magnetic resonance angiography

Highly sensitive iron oxide nanoparticles with stable, safe and efficient surface functionalization, as potential substitutes for gadolinium-based contrast agents (GBCAs) with increasing biosafety concerns, exhibit great potential for high-performance magnetic resonance angiography (MRA). Herein, we developed ultrasmall catechol-PEG-anchored ferrite nanoparticles (PEG-UMFNPs) for highly sensitive MRA. The obtained nanoprobe has a high T1 relaxivity value (7.2 mM-1 s-1) due to its ultrasmall size and Mn doping. It has a suitable hydrodynamic size of 20 nm, which prevents rapid vascular extravasation and renal clearance and prolongs its blood circulation time. In vivo MRA at 3.0 T using the nanoprobe shows that the arteries and veins of rats, even blood vessels as small as 0.32 mm, are distinctly visible, and the contrast enhancement can last for at least 1 h. In addition, due to the outstanding contrast enhancement and long circulation time, the stenosis and recanalization process of the rat's carotid artery can be continuously monitored with a single injection of the nanoprobe. Our study indicates that PEG-UMFNPs are outstanding MR imaging nanoprobes that can be used to diagnose vascular diseases without the biosafety issues of GBCAs.

Nanomaterial-Enabled Photothermal Heating and Its Use for Cancer Therapy via Localized Hyperthermia

Photothermal therapy (PTT), which employs nanoscale transducers delivered into a tumor to locally generate heat upon irradiation with near-infrared light, shows great potential in killing cancer cells through hyperthermia. The efficacy of such a treatment is determined by a number of factors, including the amount, distribution, and dissipation of the generated heat, as well as the type of cancer cell involved. The amount of heat generated is largely controlled by the number of transducers accumulated inside the tumor, the absorption coefficient and photothermal conversion efficiency of the transducer, and the irradiance of the light. The efficacy of treatment depends on the distribution of the transducers in the tumor and the penetration depth of the light. The vascularity and tissue thermal conduction both affect the dissipation of heat and thereby the distribution of temperature. The successful implementation of PTT in the clinic setting critically depends on techniques for real-time monitoring and management of temperature.

Cancer Cell Targeting Via Selective Transferrin Receptor Labeling Using Protein-Derived Carbon Dots

Carbon dot (CD) nanoparticles offer tremendous advantages as fluorescent probes in bioimaging and biosensing; however, they lack specific affinity for biomolecules, limiting their practical applications in selective targeting. Nanoparticles with intrinsic affinity for a target have applications in imaging, cytometry, therapeutics, etc. Toward that end, we report the transferrin receptor (CD71) targeting CDs, synthesized for the first time. The formation of these particles is truly groundbreaking, as direct tuning of nanoparticle affinity was achieved by simple and careful precursor selection of a protein, which has the targeting characteristic of interest. We hypothesized that the retention of the original protein's peptides on the nanoparticle surface provides the CDs with some of the function of the precursor protein, enabling selective binding to the protein's receptor. This was confirmed with FTIR (Fourier transform infrared) data and subsequent affinity-based cell assays. These transferrin (Tf)-derived CDs have been shown to possess an affinity for CD71, a cancer biomarker that is ubiquitously expressed in nearly every cancer cell line due to its central role mediating the uptake of cellular iron. The CDs were tested using the human leukemia cell line HL60 and demonstrated the selective targeting of CD71 and specific triggering of transferrin-mediated endocytosis via clathrin-coated pits. The particle characterization results reflect a carbon-based nanoparticle with bright violet fluorescence and 7.9% quantum yield in aqueous solution. These unpresented CDs proved to retain the functional properties of the precursor protein. Indicating that this process can be repeated for other disease biomarkers for applications ranging from biosensing and diagnostic bioimaging to targeted therapeutics.

Size-Dependent In Vivo Transport of Nanoparticles: Implications for Delivery, Targeting, and Clearance

Understanding the in vivo transport of nanoparticles provides guidelines for designing nanomedicines with higher efficacy and fewer side effects. Among many factors, the size of nanoparticles plays a key role in controlling their in vivo transport behaviors due to the existence of various physiological size thresholds within the body and size-dependent nano-bio interactions. Encouraged by the evolving discoveries of nanoparticle-size-dependent biological effects, we believe that it is necessary to systematically summarize the size-scaling laws of nanoparticle transport in vivo. In this review, we summarized the size effect of nanoparticles on their in vivo transport along their journey in the body: begin with the administration of nanoparticles via different delivery routes, followed by the targeting of nanoparticles to intended tissues including tumors and other organs, and eventually clearance of nanoparticles through the liver or kidneys. We outlined the tools for investigating the in vivo transport of nanoparticles as well. Finally, we discussed how we may leverage the size-dependent transport to tackle some of the key challenges in nanomedicine translation and also raised important size-related questions that remain to be answered in the future.

Recent advancement of nanomedicine-based targeted delivery for cervical cancer treatment

Cervical cancer is a huge worldwide health burden, impacting women in impoverished nations in particular. Traditional therapeutic approaches, such as surgery, radiation therapy, and chemotherapy, frequently result in systemic toxicity and ineffectiveness. Nanomedicine has emerged as a viable strategy for targeted delivery of therapeutic drugs to cancer cells while decreasing off-target effects and increasing treatment success in recent years. Nanomedicine for cervical cancer introduces several novel aspects that distinguish it from previous treatment options such as tailored delivery system, precision targeting, combination therapies, real-time monitoring and diverse nanocarriers to overcome the limitations of one another. This abstract presents recent advances in nanomedicine-based tailored delivery systems for the treatment of cervical cancer. Liposomes, polymeric nanoparticles, dendrimers, and carbon nanotubes have all been intensively studied for their ability to transport chemotherapeutic medicines, nucleic acids, and imaging agents to cervical cancer cells. Because of the way these nanocarriers are designed, they may cross biological barriers and preferentially aggregate at the tumor site, boosting medicine concentration and lowering negative effects on healthy tissues. Surface modification of nanocarriers with targeting ligands like antibodies, peptides, or aptamers improves specificity for cancer cells by identifying overexpressed receptors or antigens on the tumor surface. Furthermore, nanomedicine-based techniques have made it possible to co-deliver numerous therapeutic drugs, allowing for synergistic effects and overcoming drug resistance. In preclinical and clinical investigations, combination treatments comprising chemotherapeutic medicines, gene therapy, immunotherapy, and photodynamic therapy have showed encouraging results, opening up new avenues for individualized and multimodal treatment regimens. Furthermore, the inclusion of contrast agents and imaging probes into nanocarrier systems has enabled real-time monitoring and imaging of treatment response. This enables the assessment of therapy efficacy, the early diagnosis of recurrence, and the optimization of treatment regimens.

Development of Multifunctional Nanoencapsulated trans-Resveratrol/Chitosan Nutraceutical Edible Coating for Strawberry Preservation

Phytochemical nanoencapsulation for nutrient delivery and edible coatings for perishable food preservation are two emerging technologies. Leveraging the strong antimicrobial function of phytochemical nutrients, we propose convergent research to integrate the two technologies by embedding phytochemical-encapsulated nanoparticles in an edible coating on fresh fruits to achieve multiple functions. In particular, we report the study of an edible coating on strawberries that is composited of trans-resveratrol (R)-encapsulated nanoparticles (RNPs) embedded in a chitosan (CS) matrix. The biodegradable and biocompatible RNPs significantly increased the aqueous solubility of R by 150-fold and bioavailability by 3.5-fold after oral administration. Our results demonstrated the abilities of the RNP-embedded CS edible coating to diminish dehydration, prevent nutrient loss, inhibit microbe growth, increase nutraceutical value, preserve strawberry quality, and extend shelf life during storage at both 22 and 4 °C. Such a phytochemical nanoencapsulation-based edible coating is promising for the dual purposes of enhancing nutrient delivery and preserving perishable foods.

Magnetic Iron Oxide Nanoparticles for Brain Imaging and Drug Delivery

Central nervous system (CNS) disorders affect as many as 1.5 billion people globally. The limited delivery of most imaging and therapeutic agents into the brain is a major challenge for treatment of CNS disorders. With the advent of nanotechnologies, controlled delivery of drugs with nanoparticles holds great promise in CNS disorders for overcoming the blood-brain barrier (BBB) and improving delivery efficacy. In recent years, magnetic iron oxide nanoparticles (MIONPs) have stood out as a promising theranostic nanoplatform for brain imaging and drug delivery as they possess unique physical properties and biodegradable characteristics. In this review, we summarize the recent advances in MIONP-based platforms as imaging and drug delivery agents for brain diseases. We firstly introduce the methods of synthesis and surface functionalization of MIONPs with emphasis on the inclusion of biocompatible polymers that allow for the addition of tailored physicochemical properties. We then discuss the recent advances in in vivo imaging and drug delivery applications using MIONPs. Finally, we present a perspective on the remaining challenges and possible future directions for MIONP-based brain delivery systems.

Modulation of macrophage polarization by iron-based nanoparticles

Macrophage polarization is an essential process involved in immune regulation. In response to different microenvironmental stimulation, macrophages polarize into cells with different phenotypes and functions, most typically M1 (pro-inflammatory) and M2 (anti-inflammatory) macrophages. Iron-based nanoparticles have been widely explored and reported to regulate macrophage polarization for various biomedical applications. However, the influence factors and modulation mechanisms behind are complicated and not clear. In this review, we systemically summarized different iron-based nanoparticles that regulate macrophage polarization and function and discussed the influence factors and mechanisms underlying the modulation process. This review aims to deepen the understanding of the modulation of macrophage polarization by iron-based nanoparticles and expects to provide evidence and guidance for subsequent design and application of iron-based nanoparticles with specific macrophage modulation functions.

Nanodrug delivery systems for metabolic chronic liver diseases: advances and perspectives

Nanomedicines are revolutionizing healthcare as recently demonstrated by the Pfizer/BioNTech and Moderna COVID-2019 vaccines, with billions of doses administered worldwide in a safe manner. Nonalcoholic fatty liver disease is the most common noncommunicable chronic liver disease, posing a major growing challenge to global public health. However, due to unmet diagnostic and therapeutic needs, there is great interest in the development of novel translational approaches. Nanoparticle-based approaches offer novel opportunities for efficient and specific drug delivery to liver cells, as a step toward precision medicines. In this review, the authors highlight recent advances in nanomedicines for the generation of novel diagnostic and therapeutic tools for nonalcoholic fatty liver disease and related liver diseases.

Design of lipid-based nanoparticles for delivery of therapeutic nucleic acids

The successful development of nonviral delivery systems for nucleic acids has been reported extensively over the past number of years. Among them, lipid-based nanoparticles (LNPs) represent the most advanced platform. This review provides an overview of the state-of-the-art in LNP technology, focusing on the delivery of a range of nucleic acids. Recent advances in the development of an efficient and safe lipid-based system are critically analyzed with a particular emphasis on the rationale behind the design of LNPs and on attempts to elucidate the resulting molecular assembly and structure, their interactions with cellular proteins and biodistribution. In addition, manufacturing methods including microfluidics and their potential to influence stability and scale-up are summarized.

Magnetically Induced Brownian Motion of Iron Oxide Nanocages in Alternating Magnetic Fields and Their Application for Efficient siRNA Delivery

Hyperthermia of superparamagnetic nanoparticles driven by Néel relaxation in an alternating magnetic field (AMF) has been studied in biomedical areas; however, Brownian motion, induced by another magnetic relaxation mechanism, has not been explored extensively despite its potential in intracellular mechanoresponsive applications. We investigated whether superparamagnetic cage-shaped iron oxide nanoparticles (IO-nanocages), previously demonstrated to carry payloads inside their cavities for drug delivery, can generate Brownian motion by tuning the nanoparticle size at 335 kHz AMF frequency. The motivation of this work is to examine the magnetically driven Brownian motion for the delivery of nanoparticles allowing escape from endosomes before digestion in lysosomes and efficient delivery of siRNA cargoes to the cytoplasm. Superconducting quantum interference device (SQUID) measurements reveal the nanocage size dependence of Brownian relaxation, and a magnetic Brownian motion of 20 nm IO-nanocages improved the efficiency of siRNA delivery while endosomal membranes were observed to be compromised to release IO-nanocages in AMFs during the delivery process.

Responsive Accumulation of Nanohybrids to Boost NIR-Phototheranostics for Specific Tumor Imaging and Glutathione Depletion-Enhanced Synergistic Therapy

Dynamic regulation of nanoparticles in a controllable manner has great potential in various areas. Compared to the individual nanoparticles, the assembled nanoparticles exhibit superior properties and functions, which can be applied to achieve desirable performances. Here, a pH-responsive i-motif DNA-mediated strategy to tailor the programmable behaviors of erbium-based rare-earth nanoparticles (ErNPs) decorated copper doped metal-organic framework (CPM) nanohybrids (ECPM) under physiological conditions is reported. Within the acidic tumor microenvironment, the i-motif DNA strands are able to form quadruplex structures, resulting in the assembly of nanohybrids and selective tumor accumulation, which further amplify the ErNPs downconversion emission (1550 nm) signal for imaging. Meanwhile, the ECPM matrix acts as a near-infrared (NIR) photon-activated reactive oxygen species (ROS) amplifier through the singlet oxygen generation of the matrix in combination with its ability of intracellular glutathione depletion upon irradiation. In short, this work displays a classical example of engineering of nanoparticles, which will manifest the importance of developing nanohybrids with structural programmability in biomedical applications.

Nanodelivery of antiretroviral drugs to nervous tissues

Despite the development of effective combined antiretroviral therapy (cART), the neurocognitive impairments associated with human immunodeficiency virus (HIV) remain challenging. The presence of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCFB) impedes the adequate penetration of certain antiretroviral drugs into the brain. In addition, reports have shown that some antiretroviral drugs cause neurotoxicity resulting from their interaction with nervous tissues due to long-term systemic exposure. Therefore, the research into the effective therapeutic modality that would cater for the HIV-associated neurocognitive disorders (HAND) and ART toxicity is now receiving broad research attention. Thus, this review explores the latest information in managing HAND using a nanoparticle drug delivery system (NDDS). We discussed the neurotoxicity profile of various approved ART. Also, we explained the applications of silver nanoparticles (AgNPs) in medicine, their different synthesis methods and their interaction with nervous tissues. Lastly, while proposing AgNPs as useful nanoparticles in properly delivering ART to enhance effectiveness and minimize neurocognitive disorders, we hypothesize that the perceived toxicity of AgNPs could be minimized by taking appropriate precautions. One such precaution is using appropriate reducing and stabilizing agents such as trisodium citrate to reduce silver ion Ag + to ground state Ag0 during the synthesis. Also, the usage of medium-sized, spherical-shaped AgNPs is encouraged in AgNPs-based drug delivery to the brain due to their ability to deliver therapeutic agents across BBB. In addition, characterization and functionalization of the synthesized AgNPs are required during the drug delivery approach. Putting all these factors in place would minimize toxicity and enhance the usage of AgNPs in delivering therapeutic agents across the BBB to the targeted brain tissue and could cater for the HIV-associated neurocognitive disorders and neurotoxic effects of antiretroviral drugs (ARDs).

Long-Circulation and Brain Targeted Isoliquiritigenin Micelle Nanoparticles: Formation, Characterization, Tissue Distribution, Pharmacokinetics and Effects for Ischemic Stroke

Purpose

We designed a novel isoliquiritigenin (ISL) loaded micelle prepared with DSPE-PEG2000 as the drug carrier modified with the brain-targeting polypeptide angiopep-2 to improve the poor water solubility and low bioavailability of ISL for the treatment of acute ischemic stroke.

Methods

Thin film evaporation was used to synthesize the ISL micelles (ISL-M) modified with angiopep-2 as the brain targeted ligands. The morphology of the micelles was observed by the TEM. The particle size and zeta potential were measured via the nanometer particle size analyzer. The drug loading, encapsulation and in vitro release rates of micelles were detected by the HPLC. The UPLC-ESI-MS/MS methods were used to measure the ISL concentrations of ISL in plasma and main tissues after intravenous administration, and compared the pharmacokinetics and tissue distributions between ISL and ISL-M. In the MCAO mice model, the protective effects of ISL and ISL-M were confirmed via the behavioral and molecular biology experiments.

Results

The results showed that the drug loading of ISL-M was 7.63 ± 2.62%, the encapsulation efficiency was 68.17 ± 6.23%, the particle size was 40.87 ± 4.82 nm, and the zeta potential was -34.23 ± 3.35 mV. The in vitro release experiments showed that ISL-M had good sustained-release effect and pH sensitivity. Compared with ISL monomers, the ISL-M could significantly prolong the in vivo circulation time of ISL and enhance the accumulation in the brain tissues. The ISL-M could ameliorate the brain injury induced by the MCAO mice via inhibition of cellular autophagy and neuronal apoptosis. There were no the cellular structural damages and other adverse effects for ISL-M on the main tissues and organs.

Conclusion

The ISL-M could serve as a promising and ideal drug candidate for the clinical application of ISL in the treatment of acute ischemic stroke.

Vascular Repair by Grafting Based on Magnetic Nanoparticles

Magnetic nanoparticles (MNPs) have attracted much attention in the past few decades because of their unique magnetic responsiveness. Especially in the diagnosis and treatment of diseases, they are mostly involved in non-invasive ways and have achieved good results. The magnetic responsiveness of MNPs is strictly controlled by the size, crystallinity, uniformity, and surface properties of the synthesized particles. In this review, we summarized the classification of MNPs and their application in vascular repair. MNPs mainly use their unique magnetic properties to participate in vascular repair, including magnetic stimulation, magnetic drive, magnetic resonance imaging, magnetic hyperthermia, magnetic assembly scaffolds, and magnetic targeted drug delivery, which can significantly affect scaffold performance, cell behavior, factor secretion, drug release, etc. Although there are still challenges in the large-scale clinical application of MNPs, its good non-invasive way to participate in vascular repair and the establishment of a continuous detection process is still the future development direction.

LAPONITE® nanodisk-"decorated" Fe3O4 nanoparticles: a biocompatible nano-hybrid with ultrafast magnetic hyperthermia and MRI contrast agent ability

Magnetic Fe₃O₄ nanoparticles "decorated" by LAPONITE® nanodisks have been materialized utilizing the Schikorr reaction following a facile approach and tested as mediators of heat for localized magnetic hyperthermia (MH) and as magnetic resonance imaging (MRI) agents. The synthetic protocol involves the interaction between two layered inorganic compounds, ferrous hydroxide, Fe(OH)₂, and the synthetic smectite LAPONITE® clay Na_0.7⁺[(Si₈Mg_5.5Li_0.3)O₂₀(OH)₄]_0.7^-, towards the formation of superparamagnetic Fe₃O₄ nanoparticles, which are well decorated by the diamagnetic clay nanodisks. The latter imparts high negative ζ-potential values (up to -34.1 mV) to the particles, which provide stability against flocculation and precipitation, resulting in stable water dispersions. The obtained LAPONITE®-"decorated" Fe₃O₄ nanohybrids were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Mössbauer spectroscopy, dynamic light scattering (DLS) and vibrating sample magnetometry (VSM) at room temperature, revealing superior magnetic hyperthermia performance with specific absorption rate (SAR) values reaching 540 W g_Fe^-1 (28 kA m^-1, 150 kHz) for the hybrid material with a magnetic loading of 50 wt% Fe₃O₄/LAPONITE®. Toxicity studies were also performed with human glioblastoma (GBM) cells and human foreskin fibroblasts (HFF), which show negligible to no toxicity. Furthermore, T₂-weighted MR imaging of rodent brain shows that the LAPONITE®-"decorated" Fe₃O₄ nanohybrids predominantly affected the transverse T₂ relaxation time of tissue water, which resulted in a signal drop on the MRI T₂-weighted imaging, allowing for imaging of the magnetic nanoparticles.

Pharmacokinetics of magnetic iron oxide nanoparticles for medical applications

Magnetic iron oxide nanoparticles (MNPs) have been under intense investigation for at least the last five decades as they show enormous potential for many biomedical applications, such as biomolecule separation, MRI imaging and hyperthermia. Moreover, a large area of research on these nanostructures is concerned with their use as carriers of drugs, nucleic acids, peptides and other biologically active compounds, often leading to the development of targeted therapies. The uniqueness of MNPs is due to their nanometric size and unique magnetic properties. In addition, iron ions, which, along with oxygen, are a part of the MNPs, belong to the trace elements in the body. Therefore, after digesting MNPs in lysosomes, iron ions are incorporated into the natural circulation of this element in the body, which reduces the risk of excessive storage of nanoparticles. Still, one of the key issues for the therapeutic applications of magnetic nanoparticles is their pharmacokinetics which is reflected in the circulation time of MNPs in the bloodstream. These characteristics depend on many factors, such as the size and charge of MNPs, the nature of the polymers and any molecules attached to their surface, and other. Since the pharmacokinetics depends on the resultant of the physicochemical properties of nanoparticles, research should be carried out individually for all the nanostructures designed. Almost every year there are new reports on the results of studies on the pharmacokinetics of specific magnetic nanoparticles, thus it is very important to follow the achievements on this matter. This paper reviews the latest findings in this field. The mechanism of action of the mononuclear phagocytic system and the half-lives of a wide range of nanostructures are presented. Moreover, factors affecting clearance such as hydrodynamic and core size, core morphology and coatings molecules, surface charge and technical aspects have been described.

Recent advances in engineering iron oxide nanoparticles for effective magnetic resonance imaging

Iron oxide nanoparticle (IONP) with unique magnetic property and high biocompatibility have been widely used as magnetic resonance imaging (MRI) contrast agent (CA) for long time. However, a review which comprehensively summarizes the recent development of IONP as traditional T₂ CA and its new application for different modality of MRI, such as T₁ imaging, simultaneous T₂/T₁ or MRI/other imaging modality, and as environment responsive CA is rare. This review starts with an investigation of direction on the development of high-performance MRI CA in both T₂ and T₁ modal based on quantum mechanical outer sphere and Solomon–Bloembergen–Morgan (SBM) theory. Recent rational attempts to increase the MRI contrast of IONP by adjusting the key parameters, including magnetization, size, effective radius, inhomogeneity of surrounding generated magnetic field, crystal phase, coordination number of water, electronic relaxation time, and surface modification are summarized. Besides the strategies to improve r₂ or r₁ values, strategies to increase the in vivo contrast efficiency of IONP have been reviewed from three different aspects, those are introducing second imaging modality to increase the imaging accuracy, endowing IONP with environment response capacity to elevate the signal difference between lesion and normal tissue, and optimizing the interface structure to improve the accumulation amount of IONP in lesion. This detailed review provides a deep understanding of recent researches on the development of high-performance IONP based MRI CAs. It is hoped to trigger deep thinking for design of next generation MRI CAs for early and accurate diagnosis.

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T₂ contrast capacity of iron oxide nanoparticles (IONPs) could be improved based on quantum mechanical outer sphere theory.

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IONPs could be expand to be used as effective T₁ CAs by improving q value, extending τ_s, and optimizing interface structure.

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Environment responsive MRI CAs have been developed to improve the diagnosis accuracy.

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Introducing other imaging contrast moiety into IONPs could increase the contrast efficiency.

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Optimizing in vivo behavior of IONPs have been proved to enlarge the signal difference between normal tissue and lesion.

Targeting vascular inflammation through emerging methods and drug carriers

Acute inflammation is a common dangerous component of pathogenesis of many prevalent conditions with high morbidity and mortality including sepsis, thrombosis, acute respiratory distress syndrome (ARDS), COVID-19, myocardial and cerebral ischemia-reperfusion, infection, and trauma. Inflammatory changes of the vasculature and blood mediate the course and outcome of the pathology in the tissue site of insult, remote organs and systemically. Endothelial cells lining the luminal surface of the vasculature play the key regulatory functions in the body, distinct under normal vs. pathological conditions. In theory, pharmacological interventions in the endothelial cells might enable therapeutic correction of the overzealous damaging pro-inflammatory and pro-thrombotic changes in the vasculature. However, current agents and drug delivery systems (DDS) have inadequate pharmacokinetics and lack the spatiotemporal precision of vascular delivery in the context of acute inflammation. To attain this level of precision, many groups design DDS targeted to specific endothelial surface determinants. These DDS are able to provide specificity for desired tissues, organs, cells, and sub-cellular compartments needed for a particular intervention. We provide a brief overview of endothelial determinants, design of DDS targeted to these molecules, their performance in experimental models with focus on animal studies and appraisal of emerging new approaches. Particular attention is paid to challenges and perspectives of targeted therapeutics and nanomedicine for advanced management of acute inflammation.

Antibody-conjugated silica-coated gold nanoparticles in targeted therapy of cervical cancer

This study aimed to synthesize silica-coated gold (Au@SiO₂) nanoparticles coupled to antibodies against the scavenger receptor class B type I (SR-BI) and investigate their potential ability of visual tracking and treatment of cervical cancer. The fluorescein isothiocyanate (FITC)-labeled Au@SiO₂-SR-BI antibody was synthesized, followed by characterization determination. The expression and location of SR-BI protein in cervical cancer cells were respectively detected by western blot and immunofluorescence assays. The effects of nanoparticles on cancer cells were determined by adsorption assay and apoptosis detection, respectively. The effects of nanoparticles on tumor formation in nude mice were determined. The particle sizes of Au@SiO₂ ranged from 2-2.5 μm, and the particle size distribution was relatively uniform. MS751 showed the highest expression of SR-BI. SR-BI was located in the cytomembrane. There were more FITC-Au@SiO₂-SR-BI nanoparticles on the surface of the cells compared to FITC-Au@SiO₂. Significant apoptosis was observed in the FITC-Au@SiO₂-SR-BI-treated group in both MS751 and H8 cells. Photothermal ablation of solid tumors was observed when FITC-Au@SiO₂-SR-BI was activated using 808 nm wave. Expressions of the apoptosis-related markers including BCL2, BCLX, and p-AKT were significantly decreased, while those of caspase 3 and caspase 8 were significantly increased. The study presented a novel antibody-conjugated Au@SiO₂ nanoparticle specifically targeting molecular receptors on cancer cell membranes. Antibody-conjugated Au@SiO₂ nanoparticles may have therapeutic potential for the treatment of cervical cancer.

Hollow carbon nanospheres embedded with stoichiometric γ-Fe2O3 and GdPO4: tuning the nanospheres for in vitro and in vivo size effect evaluation

The size modulation of hollow carbon nanospheres (HCSs) has attracted great interest in the contexts of cellular uptake, drug delivery and bioimaging. In this study, a facile fabrication method was specifically used to minimize all influencing factors except for the particle size. A series of nanoparticles of hollow carbon nanospheres embedded with magnetic resonance imaging (MRI) nanoagent γ-Fe2O3 and GdPO4 nanoparticles (Fe-Gd/HCS), were successfully prepared and applied to in vitro/vivo evaluation with well-defined sizes of ∼100 nm (Fe-Gd/HCS-S), ∼200 nm (Fe-Gd/HCS-M), and ∼300 nm (Fe-Gd/HCS-L), respectively. Then the in vitro size effect of Fe-Gd/HCS was systematically investigated by bio-TEM, CLSM, CCK-8 assay, and flow cytometry revealing that Fe-Gd/HCS could be internalized and the cellular uptake amounts increase with the decrease of size. Furthermore, the in vivo size-effect behavior of Fe-Gd/HCS (∼100 nm, ∼200 nm, ∼300 nm) was tracked by MRI technique, demonstrating that all Fe-Gd/HCS can distinguish the liver, in which Fe-Gd/HCS with the smallest particle size exhibited the best performance among these nanoparticles. By leveraging on these features, Fe-Gd/HCS-S (∼100 nm) was further chosen as a theranostic agent, preliminarily presenting its capability for multi-modal imaging and therapy.

In vitro cytotoxicity, antibacterial activity and HSA and ct-DNA interaction studies of chlorogenic acid loaded on γ-Fe2O3@SiO2 as new nanoparticles

In this study, nanoparticles with both anticancer and antibacterial features were synthesized through loading chlorogenic acid (CGA) of essential oils on magnetic nanoparticles (MNPs). Characterization of γ-Fe₂O₃@SiO₂-CGA MNPs was performed using Fourier transform infrared (FT-IR) spectroscopy and transmission electron microscopy (TEM) that show effective coating of the MNPs with SiO₂ and CGA ligand and spherical shape of the nanoparticles with a mean diameter of 16 nm, respectively. The cytotoxicity study demonstrated that γ-Fe₂O₃@SiO₂-CGA MNPs had fewer toxic effects on normal cells (Huvec) than on cancerous cells (U-87 MG, A-2780 and A-549), and could be a new potential candidate for use in biological and pharmaceutical applications. The interaction of calf thymus deoxyribonucleic acid (ct-DNA) with γ-Fe₂O₃@SiO₂-CGA MNPs indicated that the anticancer activity might be associated with the DNA binding properties of γ-Fe₂O₃@SiO₂-CGA MNPs. Moreover, the interaction of γ-Fe₂O₃@SiO₂-CGA MNPs with human serum albumin (HSA) suggests that the native conformation of HSA was preserved at the level of secondary structure, indicating that the γ-Fe₂O₃@SiO₂-CGA MNPs do not show any cytotoxicity effect when they are injected into the blood. Antibacterial tests were performed and represented γ-Fe₂O₃@SiO₂-CGA MNPs attained better antibacterial function than CGA as free.

Evaluating magnetic and thermal effects of various Polymerylated magnetic iron oxide nanoparticles for combined chemo-hyperthermia

Killing cancer cells with heat: Assessing the heat-generation from Polymerylated magnetic iron oxide nanoparticles (PMNPs) for synergistic chemo-hyperthermia therapy.

Nanoparticle conjugated with aptamer anti-MUC1/Y for inflammatory arthritis

Aptamers may form well-defined three-dimensional structures binding with high affinity and stability to a specific receptor. The aptamer anti-MUC1 isoform Y is one the most used due the affinity to MUC1, which is overexpressed in several types of cancer and inflammation process. In this study we have developed, characterized, in vitro as in vivo evaluated a nanoaptamer (anti-MUC1/Y) as a nanoagent for rheumatoid arthritis treatment. The results showed that a nanoaptamer with a size range of 241 nm was produced. The entrapment efficacy was 90% with a biodistribution showing a high hepatic uptake (>98%). The results in vivo showed a potent effect in arthritis experimental model, especially in low doses. The results corroborate the applicability of this nanosystem for RA treatment.

Engineering chitosan nano-cocktail containing iron oxide and ceria: A two-in-one approach for treatment of inflammatory diseases and tracking of material delivery

In this study, modular two-in-one nano-cocktails were synthesised to provide treatment of inflammatory diseases and also enable tracking of their delivery to the disease sites. Chitosan nano-cocktails loaded with treatment module (cerium oxide nanoparticles) and imaging module (iron oxide nanoparticles) were synthesised by electrostatic self-assembly (Chit-IOCO) and ionic gelation method (Chit-TPP-IOCO), respectively. Their MRI capability, anti-inflammatory and anti-fibrosis ability were investigated. Results demonstrated that Chit-IOCO significantly reduced the expression of TNF-α and COX-2, while Chit-TPP-IOCO reduced IL-6 in the LPS-stimulated macrophages RAW264.7. Cytotoxicity studies showed that the nano-cocktails inhibited the proliferation of macrophages. Additionally, Chit-IOCO exhibited higher in vitro MRI relaxivity than Chit-TPP-IOCO, indicating that Chit-IOCO is a better MRI contrast agent in macrophages. It was possible to track the delivery of Chit-IOCO to the inflamed livers of CCl₄-treated C57BL/6 mice, demonstrated by a shortened T₂^⁎ relaxation time of the livers after injecting Chit-IOCO into mice. In vivo anti-inflammatory and blood tests demonstrated that Chit-IOCO reduced inflammation-related proteins (TNF-a, iNOS and Cox-2) and bilirubin in CCl₄ treated C57BL/6. Histology images indicated that the nano-cocktails at the treatment doses did not affect the organs of the mice. Importantly, the nano-cocktail reduced fibrosis of CCl₄-treated mouse liver. This is the first reported data on the anti-inflammation and anti-fibrosis efficacy of Chit-IOCO in C57BL/6 mouse liver inflammation model. Overall, Chit-IOCO nanoparticles have shown great potential in MR imaging/detecting and treating/therapeutic capabilities for inflammatory diseases.

A Milestone in the Chemical Synthesis of Fe3O4 Nanoparticles: Unreported Bulklike Properties Lead to a Remarkable Magnetic Hyperthermia

Among iron oxide phases, magnetite (Fe₃O₄) is often the preferred one for nanotechnological and biomedical applications because of its high saturation magnetization and low toxicity. Although there are several synthetic routes that attempt to reach magnetite nanoparticles (NPs), they are usually referred as "IONPs" (iron oxide NPs) due to the great difficulty in obtaining the monophasic and stoichiometric Fe₃O₄ phase. Added to this problem is the common increase of size/shape polydispersity when larger NPs (D > 20 nm) are synthesized. An unequivocal correlation between a nanomaterial and its properties can only be achieved by the production of highly homogeneous systems, which, in turn, is only possible by the continuous improvement of synthesis methods. There is no doubt that solving the compositional heterogeneity of IONPs while keeping them monodisperse remains a challenge for synthetic chemistry. Herein, we present a methodical optimization of the iron oleate decomposition method to obtain Fe₃O₄ single nanocrystals without any trace of secondary phases and with no need of postsynthetic treatment. The average dimension of the NPs, ranging from 20 to 40 nm, has been tailored by adjusting the total volume and the boiling point of the reaction mixture. Mössbauer spectroscopy and DC magnetometry have revealed that the NPs present a perfectly stoichiometric Fe₃O₄ phase. The high saturation magnetization (93 (2) A·m²/kg at RT) and the extremely sharp Verwey transition (at around 120 K) shown by these NPs have no precedent. Moreover, the synthesis method has been refined to obtain NPs with octahedral morphology and suitable magnetic anisotropy, which significantly improves the magnetic hyperthemia performance. The heating power of properly PEGylated nano-octahedrons has been investigated by AC magnetometry, confirming that the NPs present negligible dipolar interactions, which leads to an outstanding magnetothermal efficiency that does not change when the NPs are dispersed in environments with high viscosity and ionic strength. Additionally, the heat production of the NPs within physiological media has been directly measured by calorimetry under clinically safe conditions, reasserting the excellent adequacy of the system for hyperthermia therapies. To the best of our knowledge, this is the first time that such bulklike magnetite NPs (with minimal size/shape polydispersity, minor agglomeration, and exceptional heating power) are chemically synthesized.

Engineered strategies to enhance tumor penetration of drug-loaded nanoparticles

Nanocarriers have been widely employed in preclinical studies and clinical trials for the delivery of anticancer drugs. The most important causes of failure in clinical translation of nanocarriers is their inefficient accumulation and penetration which arises from special characteristics of tumor microenvironment such as insufficient blood supply, dense extracellular matrix, and elevated interstitial fluid pressure. Various strategies such as engineering extracellular matrix, optimizing the physicochemical properties of nanocarriers have been proposed to increase the depth of tumor penetration; however, these strategies have not been very successful so far. Novel strategies such as transformable nanocarriers, transcellular transport of peptide-modified nanocarriers, and bio-inspired carriers have recently been emerged as an advanced generation of drug carriers. In this study, the latest developments of nanocarrier-based drug delivery to solid tumor are presented with their possible limitations. Then, the prospects of advanced drug delivery systems are discussed in detail.

EDTMP ligand-enhanced water interactions endowing iron oxide nanoparticles with dual-modal MRI contrast ability

Single-modal magnetic resonance imaging (MRI) contrast agents sometimes cause signal confusion in clinical diagnosis. Utilizing ligands to endow iron oxide nanoparticles (IO NPs) with excellent dual-modal MRI contrast efficiency might be an effective strategy to improve diagnostic accuracy. This work presents the development of a special ligand-assisted one-pot approach for the preparation of super-hydrophilic magnetic NPs with excellent water dispersion, biocompatibility and T₁-T₂ dual-modal contrast enhancement properties. In addition, the strong binding capacity between the ethylenediamine tetramethylenephosphonic acid (EDTMP) ligand and water molecules induced by the presence of abundant hydrogen bonds significantly improves spin-lattice (T₁) and spin-spin (T₂) imaging of the IO core. After being modified with the EDTMP ligand, the T₂ relaxation rate of the IO core is dramatically increased from 71.78 mM^-1 s^-1 to 452.38 mM^-1 s^-1, and a moderate T₁ relaxation rate (11.61 mM^-1 s^-1) is observed simultaneously, implying that the NPs with an average size of 9.7 nm may be potential candidates as high-efficiency T₁-T₂ MRI contrast agents. This fundamental technique of using super-hydrophilicity ligands to endow IO NPs with dual-modal contrast properties without size change and damage in the T₂ contrast effect may provide a useful strategy to facilitate the application of magnetic NPs in the field of medical diagnosis.

The influence of IONPs core size on their biocompatibility and activity in in vitro cellular models

Although the key factor affecting the biocompatibility of IONPs is the core size, there is a lack of regular investigation concerning the impact of the parameter on the toxicity of these nanomaterials. Therefore, such studies were carried out in this paper. Their purpose was to compare the influence of PEG-coated-magnetite NPs with the core of 5, 10 and 30 nm on six carefully selected cell lines. The proliferation rate, viability, metabolic activity, migration activity, ROS levels and cytoskeleton architecture of cells have been evaluated for specified incubation periods. These were 24 and 72-h long incubations with IONPs administered in two doses: 5 and 25 µg Fe/ml. A decrease in viability was observed after exposure to the tested NPs for all the analyzed cell lines. This effect was not connected with core diameter but depended on the exposure time to the nanomaterials. IONPs increased not only the proliferation rate of macrophages-being phagocytic cells-but also, under certain conditions stimulated tumor cell divisions. Most likely, the increase in proliferation rate of macrophages contributed to the changes in the architecture of their cytoskeleton. The growth in the level of ROS in cells had been induced mainly by the smallest NPs. This effect was observed for HEK293T cells and two cancerous lines: U87MG (at both doses tested) and T98G (only for the higher dose). This requires further study concerning both potential toxicity of such IONPs to the kidneys and assessing their therapeutic potential in the treatment of glioblastoma multiforme.

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.

Biological behavior of nanoparticles with Zr-89 for cancer targeting based on their distinct surface composition

Nano-sized materials with properties that enable their internalization into target cells using passive targeting systems have been utilized with radioisotopes to track their pharmacokinetics in the body. Here, we report the incorporation of novel chelator-free Zr-89 using a hierarchical iron oxide nanocomposite (⁸⁹Zr-IONC). Characterization revealed that it had a rice-shape with a mean width of 160 nm. The surface of the ⁸⁹Zr-IONCs was coated by polyethyleneimine (PEI) and polyvinylpyrrolidone (PVP) to improve the cancer target efficacy. The biological behavior of the nanoparticles coated with the polymers differed significantly by the surface composition. Positron emission tomography measurements by the labeled Zr-89 effectively confirmed the cancer target capability and the fate of distribution in the body. We found that only PVP coated ⁸⁹Zr-IONC reached the tumor region while non-coated and PEI coated ⁸⁹Zr-IONC tended to be undesirably entirely cleared in the liver and spleen. The ⁸⁹Zr-incorporated iron oxide nanocomposite is significantly stable for radiolabeling despite various surface modifications, allowing the potential carrier to specifically target cancer cells. The strategy of utilizing the biocompatible PEI and PVP surface coating system for negative charged nanoparticles such as iron oxide will afford enhanced biological application.

Assessing the Biocompatibility of Multi-Anchored Glycoconjugate Functionalized Iron Oxide Nanoparticles in a Normal Human Colon Cell Line CCD-18Co

We have previously demonstrated that iron oxide nanoparticles with dopamine-anchored heterobifunctional polyethylene oxide (PEO) polymer, namely PEO-IONPs, and bio-functionalized with sialic-acid specific glycoconjugate moiety (Neu5Ac(α2-3)Gal(β1-4)-Glcβ-sp), namely GM3-IONPs, can be effectively used as antibacterial agents against target Escherichia coli. In this study, we evaluated the biocompatibility of PEO-IONPs and GM3-IONPs in a normal human colon cell line CCD-18Co via measuring cell proliferation, membrane integrity, and intracellular adenosine triphosphate (ATP), glutathione GSH, dihydrorhodamine (DHR) 123, and caspase 3/7 levels. PEO-IONPs caused a significant decrease in cell viability at concentrations above 100 μg/mL whereas GM3-IONPs did not cause a significant decrease in cell viability even at the highest dose of 500 μg/mL. The ATP synthase activity of CCD-18Co was significantly diminished in the presence of PEO-IONPs but not GM3-IONPs. PEO-IONPs also compromised the membrane integrity of CCD-18Co. In contrast, cells exposed to GM3-IONPs showed significantly different cell morphology, but with no apparent membrane damage. The interaction of PEO-IONPs or GM3-IONPs with CCD-18Co resulted in a substantial decrease in the intracellular GSH levels in a time- and concentration-dependent manner. Conversely, levels of DHR-123 increased with IONP concentrations. Levels of caspase 3/7 proteins were found to be significantly elevated in cells exposed to PEO-IONPs. Based on the results, we assume GM3-IONPs to be biocompatible with CCD-18Co and could be further evaluated for selective killing of pathogens in vivo.

Preliminary studies on drug delivery of polymeric primaquine microparticles using the liver high uptake effect based on size of particles to improve malaria treatment

Malaria is the most common parasitic disease around the world, especially in tropical and sub-tropical regions. This parasitic disease can have a rapid and severe evolution. It is transmitted by female anopheline mosquitoes. There is no reliable vaccine or diagnostic test against malaria; instead, Artesunate is used for the treatment of severe malaria and Artemisinin is used for uncomplicated falciparum malaria. However, these treatments are not efficient against severe malaria and improvements are needed. Primaquine (PQ) is one of the most widely used antimalarial drugs. It is the only available drug to date for combating the relapsing form of malaria. Nevertheless, it has severe side effects. Particle drug-delivery systems present the ability to enhance the therapeutic properties of drugs and decrease their side effects. Here, we report the development of Polymeric Primaquine Microparticles (PPM) labeled with 99mTc for therapeutic strategy against malaria infection. The amount of primaquine encapsulated into the PPM was 79.54%. PPM presented a mean size of 929.47 ± 37.72 nm, with a PDI of 0.228 ± 0.05 showing a homogeneous size for the microparticles and a monodispersive behavior. Furthermore, the biodistribution test showed that primaquine microparticles have a high liver accumulation. In vivo experiments using mice show that the PPM treatments resulted in partial efficacy and protection against the development of the parasite compared to free Primaquine. These results suggest that microparticles drug delivery systems of primaquine could be a possible approach for malaria prevention and treatment.

Overview on magnetically recyclable ferrite nanoparticles: synthesis and their applications in coupling and multicomponent reactions

Nanocatalysis is an emerging area of research that has attracted much attention over the past few years. It provides the advantages of both homogeneous as well as heterogeneous catalysis in terms of activity, selectivity, efficiency and reusability. Magnetically recoverable nanocatalysts provide a larger surface area for the chemical transformations where the organic groups can be anchored and lead to decrease in the reaction time, increase in the reaction output and improve the atom economy of the chemical reactions. Moreover, magnetic nanocatalysts provide a greener approach towards the chemical transformations and are easily recoverable by the aid of an external magnet for their reusability. This review aims to give an insight into the important work done in the field of magnetically recoverable nanocatalysts and their applications in carbon-carbon and carbon-heteroatom bond formation.

Paramagnetic Mn8Fe4-co-Polystyrene Nanobeads as a Potential T1-T2 Multimodal Magnetic Resonance Imaging Contrast Agent with In Vivo Studies

In developing a cluster-nanocarrier design, as a magnetic resonance imaging contrast agent, we have investigated the enhanced relaxivity of a manganese and iron-oxo cluster grafted within a porous polystyrene nanobead with increased relaxivity due to a higher surface area. The synthesis of the cluster-nanocarrier for the cluster Mn8Fe4O12(O2CC6H4CH═CH2)16(H2O)4, cross-linked with polystyrene (the nanocarrier), under miniemulsion conditions is described. By including a branched hydrophobe, iso-octane, the resulting nanobeads are porous and ∼70 nm in diameter. The increased surface area of the nanobeads compared to nonporous nanobeads leads to an enhancement in relaxivity; r1 increases from 3.8 to 5.2 ± 0.1 mM-1 s-1, and r2 increases from 11.9 to 50.1 ± 4.8 mM-1 s-1, at 9.4 teslas, strengthening the potential for T1 and T2 imaging. Several metrics were used to assess stability, and the porosity produced no reduction in metal stability. Synchrotron X-ray fluorescence microscopy was used to demonstrate that the nanobeads remain intact in vivo. In depth, physicochemical characteristics were determined, including extensive pharmacokinetics, in vivo imaging, and systemic biodistribution analysis.

Magnetic Molecularly Imprinted Polymers: Synthesis and Applications in the Selective Extraction of Antibiotics

Recently, magnetic molecularly imprinted polymers (MMIPs) have integrated molecular imprinting technology (MIT) and magnetic separation technology and become a novel material with specific recognition and effective separation of target molecules. Based on their special function, they can be widely used to detect contaminants such as antibiotics. The antibiotic residues in the environment not only cause harm to the balance of the ecosystem but also induce bacterial resistance to specific antibiotics. Given the above consideration, it is especially important to develop sensitive and selective methods for measuring antibiotics in the complex matrix. The combination of MMIPs and conventional analytical methods provides a rapid approach to separate and determine antibiotics residues. This article gives a systematic overview of synthetic approaches of the novel MMIPs materials, briefly introduces their use in sample pretreatment prior to antibiotic detection, and provides a perspective for future research.

Progress and prospects of magnetic iron oxide nanoparticles in biomedical applications: A review

Nanoscience has been considered as one of the most substantial research in modern science. The utilization of nanoparticle (NP) materials provides numerous advantages in biomedical applications due to their unique properties. Among various types of nanoparticles, the magnetic nanoparticles (MNPs) of iron oxide possess intrinsic features, which have been efficiently exploited for biomedical purposes including drug delivery, magnetic resonance imaging, Magnetic-activated cell sorting, nanobiosensors, hyperthermia, and tissue engineering and regenerative medicine. The size and shape of nanostructures are the main factors affecting the physicochemical features of superparamagnetic iron oxide nanoparticles, which play an important role in the improvement of MNP properties, and can be controlled by appropriate synthesis strategies. On the other hand, the proper modification and functionalization of the surface of iron oxide nanoparticles have significant effects on the improvement of physicochemical and mechanical features, biocompatibility, stability, and surface activity of MNPs. This review focuses on popular methods of fabrication, beneficial surface coatings with regard to the main required features for their biomedical use, as well as new applications.

PVP Surface-protected silica coated iron oxide nanoparticles for MR imaging application

This paper proposed an engineered mesoporous silica-coated Fe₃O₄ nanoparticle, PVPMSFe, prepared by a sol-gel/surface-protected etching mechanism as an MRI T2 contrast agent. To this end, the structural characterization of the nanocomposite was performed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, VSM, thermogravimetric analysis (TGA), TEM, FESEM, and energy-dispersive X-ray scanning electron microscopy (EDS). The findings show that the synthesized nanocomposite has a mesoporous structure with an average particle size of 11.8 nm and excellent magnetization properties. The biocompatibility of PVPMSFe was investigated by MTT assay and hemolysis assay of red blood cells and the results indicate that PVPMSFe has favorable biocompatibility. Besides, the effect of PVPMSFe was assessed with MRI relaxivity measurement (T2 signal). Regarding the in vitro MRI relaxivity measurements outputs (r₂=144.4), PVPMSFe can attenuate the T2 signal of MRI, perfectly which makes it an efficient T2 contrast agent.

Iron Oxide Nanoparticles in Bioimaging - An Immune Perspective

Iron oxide nanoparticles (IONPs) bear big hopes in nanomedicine due to their (potential) applications in tumor therapy, drug delivery or bioimaging. However, as foreign entities, such particles may be recognized by the immune system and, thus, lead to inflammation, hypersensitivity or anaphylactic shock. In addition, an overload with iron is known to cause oxidative stress. In this short review, we summarize the biological effects of such particles with a major focus on IONP-formulations used for bioimaging purposes and their effects on the human immune system. We conclude that especially the characteristics of the particles (size, shape, surface charge, coating, etc.) as well as the presence of bystander substances, such as bacterial endotoxin are important factors determining the resulting biological and immunological effects of IONPs. Further studies are needed in order to establish clear structure-activity relationships.

Size- and Surface- Dual Engineered Small Polyplexes for Efficiently Targeting Delivery of siRNA

Though siRNA-based therapy has achieved great progress, efficient siRNA delivery remains a challenge. Here, we synthesized a copolymer PAsp(-N=C-PEG)-PCys-PAsp(DETA) consisting of a poly(aspartate) block grafted with comb-like PEG side chains via a pH-sensitive imine bond (PAsp(-N=C-PEG) block), a poly(l-cysteine) block with a thiol group (PCys block), and a cationic poly(aspartate) block grafted with diethylenetriamine (PAsp(DETA) block). The cationic polymers efficiently complexed siRNA into polyplexes, showing a sandwich-like structure with a PAsp(-N=C-PEG) out-layer, a crosslinked PCys interlayer, and a complexing core of siRNA and PAsp(DETA). Low pH-triggered breakage of pH-sensitive imine bonds caused PEG shedding. The disulfide bond-crosslinking and pH-triggered PEG shedding synergistically decreased the polyplexes' size from 75 nm to 26 nm. To neutralize excessive positive charges and introduce the targeting ligand, the polyplexes without a PEG layer were coated with an anionic copolymer modified with the targeting ligand lauric acid. The resulting polyplexes exhibited high transfection efficiency and lysosomal escape capacity. This study provides a promising strategy to engineer the size and surface of polyplexes, allowing long blood circulation and targeted delivery of siRNA.

Dual Gate-Controlled Therapeutics for Overcoming Bacterium-Induced Drug Resistance and Potentiating Cancer Immunotherapy

The presence of bacteria in the tumor can cause cancer resistance to chemotherapeutics. To fight against bacterium-induced drug resistance, herein we design self-traceable nanoreservoirs that are simultaneously loaded with gemcitabine (an anticancer drug) and ciprofloxacin (an antibiotic) and are decorated with hyaluronic acid for active tumor targeting. The nanoreservoirs have a pH-sensitive gate and an enzyme-responsive gate that can be opened in the acidic and hyaluronidase-abundant tumor microenvironment to control drug release rates. Moreover, the nanoreservoirs can specifically target the tumor regions without eliciting evident toxicity to normal tissues, kill the intratumoral bacteria, and inhibit the tumor growth even in the presence of the bacteria. Unexpectedly, the nanoreservoirs can activate T cell-mediated immune responses through promoting antigen-presenting dendritic cell maturation and depleting immunosuppressive myeloid-derived suppressor cells in bacterium-infected tumors.

Recent Advances in the Use of Iron-Gold Hybrid Nanoparticles for Biomedical Applications

Recently, there has been an increased interest in iron-gold-based hybrid nanostructures, due to their combined outstanding optical and magnetic properties resulting from the usage of two separate metals. The synthesis of these nanoparticles involves thermal decomposition and modification of their surfaces using a variety of different methods, which are discussed in this review. In addition, different forms such as core-shell, dumbbell, flower, octahedral, star, rod, and Janus-shaped hybrids are discussed, and their unique properties are highlighted. Studies on combining optical response in the near-infrared window and magnetic properties of iron-gold-based hybrid nanoparticles as multifunctional nanoprobes for drug delivery, magnetic-photothermal heating as well as contrast agents during magnetic and optical imaging and magnetically-assisted optical biosensing to detect traces of targeted analytes inside the body has been reviewed.

Advancements in folate receptor targeting for anti-cancer therapy: A small molecule-drug conjugate approach

Targeted delivery combined with controlled release of drugs has a crucial role in future of personalized medicine. The majority of cancer drugs are intended to interfere with one or more cellular events. Anticancer agents can also be toxic to healthy cells, as healthy cells may also need to proliferate and avoid apoptosis. The focus of this review covers the principles, advantages, drawbacks and summarize criteria that must be met for design of small molecule-drug conjugates (SMDCs) to achieve the desired therapeutic potency with minimal toxicity. SMDCs are composed of a targeting ligand, a releasable bridge, a spacer, and a therapeutic payload. We summarize the criteria for the effective design that influences the selection of tumor specific receptor and optimum elements in the design of SMDCs. We also discuss the criteria for selecting the optimal therapeutic drug payload, spacer and linker. The linker chemistries and cleavage strategies are also discussed. Finally, we review the folate receptor targeting SMDCs that are in preclinical development and in clinical trials.