Increasing the Efficacy of Stem Cell Therapy via Triple-Function Inorganic Nanoparticles

In situ modified mesoporous silica nanoparticles: synthesis, properties and theranostic applications

Over the last 20 years, mesoporous silica nanoparticles (MSNs) have drawn considerable attention in the biomedical field due to their large surface area, porous network, biocompatibility, and abundant modification possibilities. In situ MSN modification refers to the incorporation of materials such as alkoxysilanes, ions and nanoparticles (NPs) in the silica matrix during synthesis. Matrix modification is a popular approach for endowing MSNs with additional functionalities such as imaging properties, bioactivity, and degradability, while leaving the mesopores free for drug loading. As such, in situ modified MSNs are considered promising theranostic agents. This review provides an extensive overview of different materials and modification strategies that have been used and their effect on MSN properties. We also highlight how in situ modified MSNs have been applied in theranostic applications, oncology and regenerative medicine. We conclude with perspectives on the future outlooks and current challenges for the widespread clinical use of in situ modified MSNs.

Physicochemical and biological properties of dental materials and formulations with silica nanoparticles: A narrative review

OBJECTIVE

Silica nanoparticles (SNPs) have been extensively studied and used in different dental applications to promote improved physicochemical properties, high substance loading efficiency, in addition to sustained delivery of substances for therapeutic or preventive purposes. Therefore, this study aimed to review the SNPs applications in nanomaterials and nanoformulations in dentistry, discussing their effect on physicochemical properties, biocompatibility and ability to nanocarry bioactive substances.

DATA RESOURCES

Literature searches were conducted on PubMed, Web of Science, and Scopus databases to identify studies examining the physicochemical and biological properties of dental materials and formulations containing SNPs. Data extraction was performed by one reviewer and verified by another STUDY SELECTION: A total of 50 were reviewed. In vitro studies reveal that SNPs improved the general properties of dental materials and formulations, such as microhardness, fracture toughness, flexural strength, elastic modulus and surface roughness, in addition to acting as efficient nanocarriers of substances, such as antimicrobial, osteogenic and remineralizing substances, and showed biocompatibility CONCLUSIONS: SNPs are biocompatible, improve properties of dental materials and serve as effective carriers for bioactive substances CLINICAL SIGNIFICANCE: Overall, SNPs are a promising drug delivery system that can improve dental materials biological and physicochemical and aesthetic properties, increasing their longevity and clinical performance. However, more studies are needed to elucidate SNPs short- and long-term effects in the oral cavity, mainly on in vivo and clinical studies, to prove their effectiveness and safety.

Advances in Nanoparticles in the Prevention and Treatment of Myocardial Infarction

Myocardial infarction (MI) is one of the most prevalent types of cardiovascular disease. During MI, myocardial cells become ischemic and necrotic due to inadequate blood perfusion, leading to irreversible damage to the heart. Despite the development of therapeutic strategies for the prevention and treatment of MI, their effects are still unsatisfactory. Nanoparticles represent a new strategy for the pre-treatment and treatment of MI, and novel multifunctional nanoparticles with preventive and therapeutic capabilities hold promise for the prevention and treatment of this disease. This review summarizes the common types and properties of nanoparticles, and focuses on the research progress of nanoparticles for the prevention and treatment of MI.

Biocompatibility Analysis of Bio-Based and Synthetic Silica Nanoparticles during Early Zebrafish Development

During the twenty-first century, engineered nanomaterials (ENMs) have attracted rising interest, globally revolutionizing all industrial sectors. The expanding world population and the implementation of new global policies are increasingly pushing society toward a bioeconomy, focused on fostering the adoption of bio-based nanomaterials that are functional, cost-effective, and potentially secure to be implied in different areas, the medical field included. This research was focused on silica nanoparticles (SiO2-NPs) of bio-based and synthetic origin. SiO2-NPs are composed of silicon dioxide, the most abundant compound on Earth. Due to their characteristics and biocompatibility, they are widely used in many applications, including the food industry, synthetic processes, medical diagnosis, and drug delivery. Using zebrafish embryos as in vivo models, we evaluated the effects of amorphous silica bio-based NPs from rice husk (SiO2-RHSK NPs) compared to commercial hydrophilic fumed silica NPs (SiO2-Aerosil200). We evaluated the outcomes of embryo exposure to both nanoparticles (NPs) at the histochemical and molecular levels to assess their safety profile, including developmental toxicity, neurotoxicity, and pro-inflammatory potential. The results showed differences between the two silica NPs, highlighting that bio-based SiO2-RHSK NPs do not significantly affect neutrophils, macrophages, or other innate immune system cells.

Assessment of laser-synthesized Si nanoparticle effects on myoblast motility, proliferation and differentiation: towards potential tissue engineering applications

Due to their biocompatibility and biodegradability and their unique structural and physicochemical properties, laser-synthesized silicon nanoparticles (Si-NPs) are one of the nanomaterials which have been most studied as potential theragnostic tools for non-invasive therapeutic modalities. However, their ability to modulate cell behavior and to promote proliferation and differentiation is still very little investigated or unknown. In this work, ultrapure ligand free Si-NPs of 50 ± 11.5 nm were prepared by femtosecond (fs) laser ablation in liquid. After showing the ability of Si-NPs to be internalized by murine C2C12 myoblasts, the cytotoxicity of the Si-NPs on these cells was evaluated at concentrations ranging from 14 to 224 μg mL-1. Based on these findings, three concentrations of 14, 28 and 56 μg mL-1 were thus considered to study the effect on myoblast differentiation, proliferation and motility at the molecular and phenotypical levels. It was demonstrated that up to 28 μg mL-1, the Si-NPs are able to promote the proliferation of myoblasts and their subsequent differentiation. Scratch tests were also performed revealing the positive Si-NP effect on cellular motility at 14 and 28 μg mL-1. Finally, gene expression analysis confirmed the ability of Si-NPs to promote proliferation, differentiation and motility of myoblasts even at very low concentration. This work opens up novel exciting prospects for Si-NPs made by the laser process as innovative tools for skeletal muscle tissue engineering in view of developing novel therapeutic protocols for regenerative medicine.

3D stem cell spheroids with urchin-like hydroxyapatite microparticles enhance osteogenesis of stem cells

Cell therapy (also known as cell transplantation) has been considered promising as a next-generation living-cell therapy strategy to surpass the effects of traditional drugs. However, their practical clinical uses and product conversion are hampered by the unsatisfied viability and efficacy of the transplanted cells. Herein, we propose a synergistic enhancement strategy to address these issues by constructing 3D stem cell spheroids integrated with urchin-like hydroxyapatite microparticles (uHA). Specifically, cell-sized uHA microparticles were synthesized via a simple hydrothermal method using glutamic acid (Glu, E) as the co-template with good biocompatibility and structural antimicrobial performance (denoted as E-uHA). Combining with a hanging drop method, stem cell spheroids integrated with E-uHA were successfully obtained by culturing bone marrow mesenchymal stem cells (BMSCs) with a low concentration of the E-uHA suspensions (10 μg mL-1). The resulting composite spheroids of BMSCs/E-uHA deliver a high cellular viability, migration activity, and a superior osteogenic property compared to the 2D cultured counterpart or other BMSC spheroids. This work provides an effective strategy for integrating a secondary bio-functional component into stem cell spheroids for designing more cell therapy options with boosted cellular viability and therapeutic effect.

Cascade In Situ Self-Assembly and Bioorthogonal Reaction Enable the Enrichment of Photosensitizers and Carbonic Anhydrase Inhibitors for Pretargeted Cancer Theranostics

We report here a tumor-pretargted theranostic approach for multimodality imaging-guided synergistic cancer PDT by cascade alkaline phosphatase (ALP)-mediated in situ self-assembly and bioorthogonal inverse electron demand Diels-Alder (IEDDA) reaction. Using the enzymatic catalysis of ALP that continuously catalyses the dephosphorylation and self-assembly of trans-cyclooctene (TCO)-bearing P-FFGd-TCO, a high density of fluorescent and magnetic TCO-containing nanoparticles (FMNPs-TCO) can be synthesized and retained on the membrane of tumor cells. They can act as 'artificial antigens' amenable to concurrently capture lately administrated tetrazine (Tz)-decorated PS (775NP-Tz) and carbonic anhydrase (CA) inhibitor (SA-Tz) via the fast IEDDA reaction. This two-step pretargeting process can further induce FMNPs-TCO regrowth into microparticles (FMNPs-775/SA) directly on tumor cell membranes, which is analyzed by bio-SEM and fluorescence imaging. Thus, efficient enrichment of both SA-Tz and 775NP-Tz in tumors can be achieved, allowing to alleviate hypoxia by continuously inhibiting CA activity and improving PDT of tumors. Findings show that subcutaneous HeLa tumors could be completely eradicated and no tumor recurred after irradiation with an 808 nm laser (0.33 W cm-2 , 10 min). This pretargeted approach may be applied to enrich other therapeutic agents in tumors to improve targeted therapy.

Single Doping for Triple Functions: Integrated Theranostic Nanoplatforms for Multimodal Image-Guided Tumor Therapy

Accurate location and efficient treatment of diseases by multifunctional nanoplatforms are appealing but face great challenges. Theranostic agents through the physical combination of different functional nanoparticles are demonstrated to be effective. Yet, the complicated biological environment often leads to ambiguous fates of each agent, which fails to keep the behaviors of imaging and therapeutic components in a simultaneous manner. Herein, "integrated" theranostic NPs, Gd-doped CuWO4 (CWG) with strong near-infrared (808 nm) absorption, the longest absorption peak of reported CuWO4 , located in the biological transparent window, are constructed. The single doping of trace amount of Gd not only endows them with a distinguished magnetic resonance imaging capability (r1 = 12.01 mM-1 s-1 ), but also concurrently imposes great effect on the valence states of matrix ion (Cu), as evidenced by theoretical calculation results. The charge distribution shift of Cu would facilitate ·OH generation, beneficial for chemodynamic therapy (CDT). Moreover, CWG NPs display remarkable photoacoustic (PA) and computed tomography (CT) imaging capabilities (S = 10.33 HU mM-1 ). Such integrated theranostics afford a paradigm for multimodal imaging-guided synergistic therapy with all-in-one single nanoparticle.

Cargo-loaded lipid-shielded breakable organosilica nanocages for enhanced drug delivery

The recent nanomedicine advancements have introduced a variety of smart nanoparticles in cancer treatment and diagnostics. However, their application to the clinic is still hindered by several challenges related to their biocompatibility, elimination and biodistribution. Here we propose breakable organosilica mesoporous nanoparticles, i.e. nanocages, able to efficiently incorporate cargo molecules and be coated, with different lipid compositions, to enhance their biomimetic behaviour. We exploit the electrostatic interactions between the organosilica surface and the opposite charge of the lipid mixtures in order to obtain an efficient organosilica coverage. The lipid-coated nanocages are proved to have an incredibly high hemocompatibility, significantly increased with respect to pristine nanocages, and excellent colloidal stability and biocompatibility. The cargo-loaded and lipid-coated nanocages are tested and compared in vitro on two different cancer cell lines, demonstrating the key role played by the lipid coating in mediating the internalization of the nanocages, evaluated by the enhanced and rapid cellular uptake. The efficient intracellular delivery of the therapeutic agents is then assured by the destruction of the organosilica, due to the disulfide bridges, introduced into the silica framework, that in reducing media, like the intracellular one, are reduced to thiols causing the breaking of the nanoparticles. The possibility to image and effectively kill cancer cells demonstrates the potentiality of the lipid-coated nanocages as a powerful tool in anticancer research and as a promising smart theranostic platform.

Inorganic nanoparticle-integrated mesenchymal stem cells: A potential biological agent for multifaceted applications

Mesenchymal stem cell (MSC)-based therapies are flourishing. MSCs could be used as potential therapeutic agents for regenerative medicine due to their own repair function. Meanwhile, the natural predisposition toward inflammation or injury sites makes them promising carriers for targeted drug delivery. Inorganic nanoparticles (INPs) are greatly favored for their unique properties and potential applications in biomedical fields. Current research has integrated INPs with MSCs to enhance their regenerative or antitumor functions. This model also allows the in vivo fate tracking of MSCs in multiple imaging modalities, as many INPs are also excellent contrast agents. Thus, INP-integrated MSCs would be a multifunctional biologic agent with great potential. In this review, the current roles performed by the integration of INPs with MSCs, including (i) enhancing their repair and regeneration capacity via the improvement of migration, survival, paracrine, or differentiation properties, (ii) empowering tumor-killing ability through agent loaded or hyperthermia, and (iii) conferring traceability are summarized. An introduction of INP-integrated MSCs for simultaneous treatment and tracking is also included. The promising applications of INP-integrated MSCs in future treatments are emphasized and the challenges to their clinical translation are discussed.

Synergistic Effect of Magneto-Mechanical Bioengineered Stem Cells and Magnetic Field to Alleviate Osteoporosis

Therapeutic bioengineering based on stem cell therapy holds great promise in biomedical applications. However, the application of this treatment is limited in orthopedics because of their poor survival, weak localization, and low cell retention. In this work, magneto-mechanical bioengineered cells consisting of magnetic silica nanoparticles (MSNPs) and mesenchymal stem cells (MSCs) are prepared to alleviate osteoporosis. The magneto-mechanical bioengineered MSCs with spatial localization, cell retention, and directional tracking capabilities could be mediated by a guided magnetic field (MF) in vitro and in vivo. Furthermore, high uptake rates of the MSNPs ensure the efficient construction of magnetically controlled MSCs within 2 h. In conjunction with external MF, the magneto-mechanical bioengineered MSCs have the potential for the activation of the YAP/β-catenin signaling pathway, which could further promote osteogenesis, mineralization, and angiogenesis. The synergistic effects of MSNPs and guided MF could also decline bone resorption to rebalance bone metabolism in bone loss diseases. In vivo experiments confirm that the functional MSCs and guided MF could effectively alleviate postmenopausal osteoporosis, and the bone mass of the treated osteoporotic bones by using the bioengineered cells for 6 weeks is nearly identical to that of the healthy ones. Our results provide a new avenue for osteoporosis management and treatment, which contribute to the future advancement of magneto-mechanical bioengineering and treatment.

Silica-Based Advanced Nanoparticles For Treating Ischemic Disease

Recently, various attempts have been made to apply diverse types of nanoparticles in biotechnology. Silica nanoparticles (SNPs) have been highlighted and studied for their selective accumulation in diseased parts, strong physical and chemical stability, and low cytotoxicity. SNPs, in particular, are very suitable for use in drug delivery and bioimaging, and have been sought as a treatment for ischemic diseases. In addition, mesoporous silica nanoparticles have been confirmed to efficiently deliver various types of drugs owing to their porous structure. Moreover, there have been innovative attempts to treat ischemic diseases using SNPs, which utilize the effects of Si ions on cells to improve cell viability, migration enhancement, and phenotype modulation. Recently, external stimulus-responsive treatments that control the movement of magnetic SNPs using external magnetic fields have been studied. This review addresses several original attempts to treat ischemic diseases using SNPs, including particle synthesis methods, and presents perspectives on future research directions.

Cobalt protoporphyrin-induced nano-self-assembly for CT imaging, magnetic-guidance, and antioxidative protection of stem cells in pulmonary fibrosis treatment

Mesenchymal stem cells (MSCs) transplantation is a promising approach for pulmonary fibrosis (PF), however it is impeded by several persistent challenges, including the lack of long-term tracking, low retention, and poor survival of MSCs, as well as the low labeling efficiency of nanoprobes. Herein, a cobalt protoporphyrin IX (CoPP) aggregation-induced strategy is applied to develop a multifunctional nano-self-assembly (ASCP) by combining gold nanoparticle (AuNPs), superparamagnetic iron oxide nanoparticles (SPIONs), and CoPP through a facile solvent evaporation-driven approach. Since no additional carrier materials are employed during the synthesis, high loading efficiency of active ingredients and excellent biocompatibility are achieved. Additionally, facile modification of the ASCPs with bicyclo[6.1.0]nonyne (BCN) groups (named as ASCP-BCN) enables them to effectively label MSCs through bioorthogonal chemistry. The obtained ASCP-BCN could not only help to track MSCs with AuNP-based computed tomography (CT) imaging, but also achieve an SPIONs-assisted magnetic field based improvement in the MSCs retention in lungs as well as promoted the survival of MSCs via the sustained release of CoPP. The in vivo results demonstrated that the labeled MSCs improved the lung functions and alleviated the fibrosis symptoms in a bleomycin–induced PF mouse model. Collectively, a novel ASCP-BCN multifunctional nanoagent was developed to bioorthogonally-label MSCs with a high efficiency, presenting a promising potential in the high-efficient MSC therapy for PF.

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Cobalt protoporphyrin IX induces the formation of multifunctional nanoagent by self-assembly without additional carriers.

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Bioorthogonal reaction increases the stem cell labeling efficiency of nanoagents.

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Gold nanoparticles-based CT imaging enables stem cell tracking in vivo.

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Magnetic guidance and cytoprotection functions improve the therapeutic effect of stem cell therapy for pulmonary fibrosis.

Nanoparticle and Stem Cell Combination Therapy for the Management of Stroke

Stroke is currently one of the primary causes of morbidity and mortality worldwide. Unfortunately, the available treatments for stroke are still extremely limited. Indeed, stem cell (SC) therapy is a new option for the treatment of stroke that could significantly expand the therapeutic time window of stroke. Some proposed mechanisms for stroke-based SC therapy are the incorporation of SCs into the host brain to replace dead or damaged cells/tissues. Moreover, acute cell delivery can inhibit apoptosis and decrease lesion size, providing immunomudolatory and neuroprotection effects. However, several major SC problems related to SCs such as homing, viability, uncontrolled differentiation, and possible immune response, have limited SC therapy. A combination of SC therapy with nanoparticles (NPs) can be a solution to address these challenges. NPs have received considerable attention in regulating and controlling the behavior of SCs because of their unique physicochemical properties. By reviewing the pathophysiology of stroke and the therapeutic benefits of SCs and NPs, we hypothesize that combined therapy will offer a promising future in the field of stroke management. In this work, we discuss recent literature in SC research combined with NP-based strategies that may have a synergistic outcome after stroke incidence.

Biomaterials-Based Cell Therapy for Myocardial Tissue Regeneration

Cardiovascular diseases (CVDs) have been the leading cause of death worldwide during the past several decades. Cell loss is the main problem that results in cardiac dysfunction and further mortality. Cell therapy aiming to replenish the lost cells is proposed to treat CVDs especially ischemic heart diseases which lead to a big portion of cell loss. Due to the direct injection's low cell retention and survival ratio, cell therapy using biomaterials as cell carriers has attracted more and more attention because of their promotion of cell delivery and maintenance at the aiming sites. In this review, the three main factors involved in cell therapy for myocardial tissue regeneration: cell sources (somatic cells, stem cells, and engineered cells), chemical components of cell carriers (natural materials, synthetic materials, and electroactive materials), and categories of cell delivery materials (patches, microspheres, injectable hydrogels, nanofiber and microneedles, etc.) are systematically summarized. An introduction of the methods including magnetic resonance/radionuclide/photoacoustic and fluorescence imaging for tracking the behavior of transplanted cells in vivo is also included. Current challenges of biomaterials-based cell therapy and their future directions are provided to give both beginners and professionals a clear view of the development and future trends in this area.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Nanoparticles Targeting the Molecular Pathways of Heart Remodeling and Regeneration

Cardiovascular diseases are the main cause of death worldwide, a trend that will continue to grow over the next decade. The heart consists of a complex cellular network based mainly on cardiomyocytes, but also on endothelial cells, smooth muscle cells, fibroblasts, and pericytes, which closely communicate through paracrine factors and direct contact. These interactions serve as valuable targets in understanding the phenomenon of heart remodeling and regeneration. The advances in nanomedicine in the controlled delivery of active pharmacological agents are remarkable and may provide substantial contribution to the treatment of heart diseases. This review aims to summarize the main mechanisms involved in cardiac remodeling and regeneration and how they have been applied in nanomedicine.

Nanomaterials as Ultrasound Theragnostic Tools for Heart Disease Treatment/Diagnosis

A variety of different nanomaterials (NMs) such as microbubbles (MBs), nanobubbles (NBs), nanodroplets (NDs), and silica hollow meso-structures have been tested as ultrasound contrast agents for the detection of heart diseases. The inner part of these NMs is made gaseous to yield an ultrasound contrast, which arises from the difference in acoustic impedance between the interior and exterior of such a structure. Furthermore, to specifically achieve a contrast in the diseased heart region (DHR), NMs can be designed to target this region in essentially three different ways (i.e., passively when NMs are small enough to diffuse through the holes of the vessels supplying the DHR, actively by being associated with a ligand that recognizes a receptor of the DHR, or magnetically by applying a magnetic field orientated in the direction of the DHR on a NM responding to such stimulus). The localization and resolution of ultrasound imaging can be further improved by applying ultrasounds in the DHR, by increasing the ultrasound frequency, or by using harmonic, sub-harmonic, or super-resolution imaging. Local imaging can be achieved with other non-gaseous NMs of metallic composition (i.e., essentially made of Au) by using photoacoustic imaging, thus widening the range of NMs usable for cardiac applications. These contrast agents may also have a therapeutic efficacy by carrying/activating/releasing a heart disease drug, by triggering ultrasound targeted microbubble destruction or enhanced cavitation in the DHR, for example, resulting in thrombolysis or helping to prevent heart transplant rejection.

Ischemic Microenvironment-Responsive Therapeutics for Cardiovascular Diseases

Cardiovascular diseases caused by ischemia are attracting considerable attention owing to its high morbidity and mortality worldwide. Although numerous agents with cardioprotective benefits have been identified, their clinical outcomes are hampered by their low bioavailability, poor drug solubility, and systemic adverse effects. Advances in nanoscience and nanotechnology provide a new opportunity to effectively deliver drugs for treating ischemia-related diseases. In particular, cardiac ischemia leads to a characteristic pathological environment called an ischemic microenvironment (IME), significantly different from typical cardiac regions. These remarkable differences between ischemic sites and normal tissues have inspired the development of stimuli-responsive systems for the targeted delivery of therapeutic drugs to damaged cardiomyocytes. Recently, many biomaterials with intelligent properties have been developed to enhance the therapeutic benefits of drugs for the treatment of myocardial ischemia. Strategies for stimuli-responsive drug delivery and release based on IME include reactive oxygen species, pH-, hypoxia-, matrix metalloproteinase-, and platelet-inspired targeting strategies. In this review, state-of-the-art IME-responsive biomaterials for the treatment of myocardial ischemia are summarized. Perspectives, limitations, and challenges are also discussed for the further development of innovative and effective approaches to treat ischemic diseases with high effectiveness and biocompatibility.

Nanotechnology in cardiac stem cell therapy: cell modulation, imaging and gene delivery

The wide arena of applications opened by nanotechnology is multidimensional. It is already been proven that its prominence can continuously influence human life. The role of stem cells in curing degenerative diseases is another major area of research. Cardiovascular diseases are one of the major causes of death globally. Nanotechnology-assisted stem cell therapy could be used to tackle the challenges faced in the management of cardiovascular diseases. In spite of the positive indications and proven potential of stem cells to differentiate into cardiomyocytes for cardiac repair and regeneration during myocardial infarction, this therapeutic approach still remains in its infancy due to several factors such as non-specificity of injected cells, insignificant survival rate, and low cell retention. Attempts to improve stem cell therapy using nanoparticles have shown some interest among researchers. This review focuses on the major hurdles associated with cardiac stem cell therapy and the role of nanoparticles to overcome the major challenges in this field, including cell modulation, imaging, tracking and gene delivery.

This review summarizes the potential challenges present in cardiac stem cell therapy and the major role of nanotechnology to overcome these challenges including cell modulation, tracking and imaging of stem cells.

Nanoparticles: Promising Tools for the Treatment and Prevention of Myocardial Infarction

Despite several recent advances, current therapy and prevention strategies for myocardial infarction are far from satisfactory, owing to limitations in their applicability and treatment effects. Nanoparticles (NPs) enable the targeted and stable delivery of therapeutic compounds, enhance tissue engineering processes, and regulate the behaviour of transplants such as stem cells. Thus, NPs may be more effective than other mechanisms, and may minimize potential adverse effects. This review provides evidence for the view that function-oriented systems are more practical than traditional material-based systems; it also summarizes the latest advances in NP-based strategies for the treatment and prevention of myocardial infarction.

De novo Drug Delivery Modalities for Treating Damaged Hearts: Current Challenges and Emerging Solutions

Cardiovascular disease (CVD) is the leading cause of mortality, resulting in approximately one-third of deaths worldwide. Among CVD, acute myocardial infarctions (MI) is the leading cause of death. Current treatment modalities for treating CVD have improved over the years, but the demand for new and innovative therapies has been on the rise. The field of nanomedicine and nanotechnology has opened a new paradigm for treating damaged hearts by providing improved drug delivery methods, specifically targeting injured areas of the myocardium. With the advent of innovative biomaterials, newer therapeutics such as growth factors, stem cells, and exosomes have been successfully delivered to the injured myocardial tissue, promoting improvement in cardiac function. This review focuses on three major drug delivery modalities: nanoparticles, microspheres, and hydrogels, and their potential for treating damaged hearts following an MI.

Advances in Nanomaterials for Injured Heart Repair

Atherosclerotic cardiovascular disease (ASCVD) is one of the leading causes of mortality worldwide. Because of the limited regenerative capacity of adult myocardium to compensate for the loss of heart tissue after ischemic infarction, scientists have been exploring the possible mechanisms involved in the pathological process of ASCVD and searching for alternative means to regenerate infarcted cardiac tissue. Although numerous studies have pursued innovative solutions for reversing the pathological process of ASCVD and improving the effectiveness of delivering therapeutics, the translation of those advances into downstream clinical applications remains unsatisfactory because of poor safety and low efficacy. Recently, nanomaterials (NMs) have emerged as a promising new strategy to strengthen both the efficacy and safety of ASCVD therapy. Thus, a comprehensive review of NMs used in ASCVD treatment will be useful. This paper presents an overview of the pathophysiological mechanisms of ASCVD and the multifunctional mechanisms of NM-based therapy, including antioxidative, anti-inflammation and antiapoptosis mechanisms. The technological improvements of NM delivery are summarized and the clinical transformations concerning the use of NMs to treat ASCVD are examined. Finally, this paper discusses the challenges and future perspectives of NMs in cardiac regeneration to provide insightful information for health professionals on the latest advancements in nanotechnologies for ASCVD treatment.

Iron Oxide Nanoparticles in Regenerative Medicine and Tissue Engineering

In recent years, many promising nanotechnological approaches to biomedical research have been developed in order to increase implementation of regenerative medicine and tissue engineering in clinical practice. In the meantime, the use of nanomaterials for the regeneration of diseased or injured tissues is considered advantageous in most areas of medicine. In particular, for the treatment of cardiovascular, osteochondral and neurological defects, but also for the recovery of functions of other organs such as kidney, liver, pancreas, bladder, urethra and for wound healing, nanomaterials are increasingly being developed that serve as scaffolds, mimic the extracellular matrix and promote adhesion or differentiation of cells. This review focuses on the latest developments in regenerative medicine, in which iron oxide nanoparticles (IONPs) play a crucial role for tissue engineering and cell therapy. IONPs are not only enabling the use of non-invasive observation methods to monitor the therapy, but can also accelerate and enhance regeneration, either thanks to their inherent magnetic properties or by functionalization with bioactive or therapeutic compounds, such as drugs, enzymes and growth factors. In addition, the presence of magnetic fields can direct IONP-labeled cells specifically to the site of action or induce cell differentiation into a specific cell type through mechanotransduction.

Environmental Aspects of Oxide Nanoparticles: Probing Oxide Nanoparticle Surface Processes Under Different Environmental Conditions

Surface chemistry affects the physiochemical properties of nanoparticles in a variety of ways. Therefore, there is great interest in understanding how nanoparticle surfaces evolve under different environmental conditions of pH and temperature. Here, we discuss the use of vibrational spectroscopy as a tool that allows for in situ observations of oxide nanoparticle surfaces and their evolution due to different surface processes. We highlight oxide nanoparticle surface chemistry, either engineered anthropogenic or naturally occurring geochemical nanoparticles, in complex media, with a focus on the impact of (a) pH on adsorption, intermolecular interactions, and conformational changes; (b) surface coatings and coadsorbates on protein adsorption kinetics and protein conformation; (c) surface adsorption on the temperature dependence of protein structure phase changes; and (d) the use of two-dimensional correlation spectroscopy to analyze spectroscopic results for complex systems. An outlook of the field and remaining challenges is also presented.

Mononuclear phagocyte system blockade using extracellular vesicles modified with CD47 on membrane surface for myocardial infarction reperfusion injury treatment

Mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) with anti-apoptotic and anti-inflammatory properties have been intensively studied. However, rapid clearance by the mononuclear phagocyte system remains a huge barrier for the delivery of extracellular vesicle contents into target organs and restricts its wider application, particularly in the heart. CD47 is a transmembrane protein that enables cancer cells to evade clearance by macrophages through CD47^- signal regulatory proteinα binding, which initiates a "don't eat me" signal. This study aimed to explore the biodistribution and delivery efficiency of EVs carrying the membrane protein CD47 and specific anti-apoptotic miRNAs. EVs were isolated from MSCs overexpressing CD47 (CD47-EVs) and identified. Fluorescence-labeled EVs were injected through the tail vein and tracked using fluorescence imaging. In silico analysis was performed to determine miRNA profiles in MSCs and in a heart-derived H9c2 cardiomyoblast cell line under hypoxia vs. normoxia conditions. Electro CD47-EV was constructed by encapsulating purified CD47-EV with miR-21a via electroporation. The effect of miR21-EVs on the pro-apoptotic gene encoding phosphatase and tensin homolog (PTEN) was evaluated by dual-luciferase assay, qPCR, and western blotting. Exogenous miR21 distribution, PTEN protein level, blood vessel density, anti-apoptotic effect by TdT-mediated dUTP nick-end labeling staining, and macrophage and leukocyte infiltration in the myocardium were assessed by immunofluorescence staining. Cardiac functional recovery during the early stage and recovery period was evaluated using echocardiography. The results showed that CD47-EVs were still detectable in the plasma 120 min after the tail vein injection, compared to the detection time of less than 30 min observed with the unmodified EVs. More strikingly, CD47-EVs preferentially accumulated in the heart in the ischemia-reperfusion (I/R) + CD47-EV group [heart total fluorescence radiance ( × 10⁵ Photons/sec/cm²/sr) 51.62 ± 11.30 v.s. 10.08 ± 3.15 in the I/R + unmodified EVs group] 8 h post-injection. Exogenous miR-21 is efficiently internalized into cardiomyocytes, inhibits apoptosis, alleviates inflammation, and improves cardiac function. In conclusion, electro CD47-EVs efficiently improve biodistribution in the heart, shedding new light on the application of a two-step EV delivery method (CD47 genetic modification followed by therapeutic content electrotransfection) as a potential therapeutic tool for myocardial I/R injury that may benefit patients in the future.

Gold Nanorod-Melanin Hybrids for Enhanced and Prolonged Photoacoustic Imaging in the Near-Infrared-II Window

Photoacoustic (PA) imaging holds great promise as a noninvasive imaging modality. Gold nanorods (GNRs) with absorption in the second near-infrared (NIR-II) window have emerged as excellent PA probes because of their tunable optical absorption, surface modifiability, and low toxicity. However, pristine GNRs often undergo shape transition upon laser illumination due to thermodynamic instability, leading to a reduced PA signal after a few seconds of imaging. Here, we report monodisperse GNR-melanin nanohybrids where a tunable polydopamine (PDA) coating was conformally coated on GNRs. GNR@PDAs showed a threefold higher PA signal than pristine GNRs due to the increased optical absorption, cross-sectional area, and thermal confinement. More importantly, the PA signal of GNR@PDAs only decreased by 29% during the 5 min of laser illumination in the NIR-II window, while significant attenuation (77%) was observed for GNRs. The GNR@PDAs maintained 87% of its original PA signal in vivo even after 10 min of laser illumination. This PDA-enabled strategy affords a rational design for robust PA imaging probes and provides more opportunities for other types of photomediated biomedicines, such as photothermal and photodynamic regimens.

Application of low-intensity pulsed therapeutic ultrasound on mesenchymal precursors does not affect their cell properties

Ultrasound is considered a safe and non-invasive tool in regenerative medicine and has been used in the clinic for more than twenty years for applications in bone healing after the approval of the Exogen device, also known as low-intensity pulsed ultrasound (LIPUS). Beyond its effects on bone health, LIPUS has also been investigated for wound healing of soft tissues, with positive results for various cell processes including cell proliferation, migration and angiogenesis. As LIPUS has the potential to treat chronic skin wounds, we sought to evaluate the effects produced by a conventional therapeutic ultrasound device at low intensities (also considered LIPUS) on the migration capacity of mouse and human skin mesenchymal precursors (s-MPs). Cells were stimulated for 3 days (20 minutes per day) using a traditional ultrasound device with the following parameters: 100 mW/cm2 with 20% duty cycle and frequency of 3 MHz. At the parameters used, ultrasound failed to affect s-MP proliferation, with no evident changes in morphology or cell groupings, and no changes at the cytoskeletal level. Further, the migration and invasion ability of s-MPs were unaffected by the ultrasound protocol, and no major changes were detected in the gene/protein expression of ROCK1, integrin β1, laminin β1, type I collagen and transforming growth factor β1. Finally, RNA-seq analysis revealed that only 10 genes were differentially expressed after ultrasound stimulation. Among them, 5 encode for small nuclear RNAs and 2 encode for proteins belonging to the nuclear pore complex. Considering the results overall, while the viability of s-MPs was not affected by ultrasound stimulation and no changes were detected in proliferation/migration, RNA-seq analysis would suggest that s-MPs do respond to ultrasound. The use of 100 mW/cm2 intensity or conventional therapeutic ultrasound devices might not be optimal for the stimulation the properties of cell populations. Future studies should investigate the potential application of ultrasound using variations of the tested parameters.

Effect of Quercetin-Loaded Mesoporous Silica Nanoparticles on Myocardial Ischemia-Reperfusion Injury in Rats and Its Mechanism

BACKGROUND

Quercetin has potential value in treating cardiovascular diseases, but it is not suitable for clinical application due to its own water solubility. The limitation of quercetin can be distinctly ameliorated by delivering it with nanocarriers.

OBJECTIVE

To determine the effect of quercetin-loaded mesoporous silica nanoparticles (Q-MSNs) on myocardial ischemia-reperfusion injury in rats and its mechanism.

METHODS

Q-MSNs were synthesized, and the morphology of Q-MSNs and MSNs was characterized by transmission electron microscopy and dynamic light scattering technique, respectively. Healthy rats were enrolled and randomly divided into a sham operation control group, an ischemia-reperfusion (IR) group, an IR+Q group, an IR+Q-MSNs group, and an MSNs group (each n = 10). Rats in the sham operation group were not treated with ischemia reperfusion, but given normal perfusion meantime. Rats in the sham operation control group, IR group, and MSNs group were given normal saline for 10 days before ischemia reperfusion, and rats in the IR+Q group and IR+Q-MSNs group were given drugs by gavage for 10 days before ischemia reperfusion. Primary myocardial cells were sampled from SD neonatal rats to construct hypoxia/reoxygenation myocardial cell models. The myocardial cells were assigned to a control group, IR group, quercetin (Q) group, Q-MSNs group, and MSNs group. Except for the control group, all the other groups were treated with hypoxia/reoxygenation. Cells in the Q group were treated with quercetin (10 μM, 20 μM, 40 μM) for 24 h in advance and then treated with measures to cause hypoxia-reoxygenation injury. Cells in the Q-MSNs group were treated with the same concentration of loaded quercetin and the same method used for the Q group. The myocardial apoptosis, myocardial infarction, ventricular remodeling, hemodynamic indexes, physiological and biochemical indexes, and JAK2/STAT3 pathway expression of each group were detected, and the apoptosis, viability, oxidative stress, and JAK2/STAT3 pathway expression of primary myocardial cells in each group were also detected.

RESULTS

Quercetin significantly activated the JAK2/STAT3 pathway in vivo and in vitro, and MSNs intensified the activation. Compared with quercetin, Q-MSNs were more effective in inhibiting cell apoptosis and oxidative stress, reducing myocardial infarction size, improving ventricular remodeling and cardiac function-related biochemical indexes, and promoting the recovery of cardiac blood flow.

CONCLUSION

Q-MSNs can significantly enhance the activation effect of quercetin on JAK2/STAT3 pathway, thus enhancing its protection on the heart of MIRI rats.

Gold nanoparticles to enhance ophthalmic imaging

The use of gold nanoparticles as diagnostic tools is burgeoning, especially in the cancer community with a focus on theranostic applications to both cancer diagnosis and treatment. Gold nanoparticles have also demonstrated great potential for use in diagnostic and therapeutic approaches in ophthalmology. Although many ophthalmic imaging modalities are available, there is still a considerable unmet need, in particular for ophthalmic molecular imaging for the early detection of eye disease before morphological changes are more grossly visible. An understanding of how gold nanoparticles are leveraged in other fields could inform new ways they could be utilized in ophthalmology. In this paper, we review current ophthalmic imaging techniques and then identify optical coherence tomography (OCT) and photoacoustic imaging (PAI) as the most promising technologies amenable to the use of gold nanoparticles for molecular imaging. Within this context, the development of gold nanoparticles as OCT and PAI contrast agents are reviewed, with the most recent developments described in detail.

Engineered Fe3O4-based nanomaterials for diagnosis and therapy of cancer

Recent developments of Fe₃O₄ NP-based theranostic nanoplatforms and their applications in tumor-targeted imaging and therapy.

Fusogenic liposome-enhanced cytosolic delivery of magnetic nanoparticles

Fusogenic liposomes facilitate MNPs passage into the cytosol and enable direct contact between MNPs and organelles other than endosomes.

Gas-Stabilizing Sub-100 nm Mesoporous Silica Nanoparticles for Ultrasound Theranostics

Recent studies have demonstrated that gas-stabilizing particles can generate cavitating micron-sized bubbles when exposed to ultrasound, offering excellent application potential, including ultrasound imaging, drug delivery, and tumor ablation. However, the majority of the reported gas-stabilizing particles are relatively large (>200 nm), and smaller particles require high acoustic pressures to promote cavitation. Here, this paper reports the preparation of sub-100 nm gas-stabilizing nanoparticles (GSNs) that can initiate cavitation at low acoustic intensities, which can be delivered using a conventional medical ultrasound imaging system. The highly echogenic GSNs (F127-hMSN) were prepared by carefully engineering the surfaces of ∼50 nm mesoporous silica nanoparticles. It was demonstrated that the F127-hMSNs could be continuously imaged with ultrasound in buffer or biological solutions or agarose phantoms for up to 20 min. Also, the F127-hMSN can be stored in phosphate-buffered saline for at least a month with no loss in ultrasound responsiveness. The particles significantly degraded when diluted in simulated body fluids, indicating possible biodegradation of the F127-hMSNs in vivo. Furthermore, at ultrasound imaging conditions, F127-hMSNs did not cause detectable cell death, supporting the potential safety of these particles. Finally, strong cavitation activity generation by the F127-hMSNs under high-intensity focused ultrasound insonation was demonstrated and applied to effectively ablate cancer cells.

Engineering Plasmonic Nanoparticles for Enhanced Photoacoustic Imaging

Photoacoustic (PA) imaging is an emerging imaging modality whereby pulsed laser illumination generates pressure transients that are detectable using conventional ultrasound. Plasmonic nanoparticles such as gold nanorods and nanostars are often used as PA contrast agents. The thermoelastic expansion model best describes the PA response from plasmonic nanoparticles: Light absorption causes a small increase in temperature leading to thermoelastic expansion. The conversion of optical energy into pressure waves (po) is dependent on several features: (i) the absorption coefficient (μa), (ii) the thermal expansion coefficient (β), (iii) specific heat capacity (Cp) of the absorbing material, (iv) speed of sound in the medium (c), and (v) the illumination fluence (F). Controlling the geometry, composition, coatings, and solvents around plasmonic nanostructures can help tune these variables to generate the optimum PA signal. The thermoelastic expansion model is not limited to plasmonic structures and holds true for all absorbing molecules. Here, we focus on ways to engineer these variables to enhance the PA response from plasmonic nanoparticles.

Simultaneous Intravital Optical and Acoustic Monitoring of Ultrasound-Triggered Nanobubble Generation and Extravasation

Ultrasound-activated nanobubbles are being widely investigated as contrast agents and therapeutic vehicles. Nanobubbles hold potential for accessing the tumor extravascular compartment, though this relies on clinically debated passive accumulation for which evidence to date is indirect. We recently reported ultrasound-triggered conversion of high payload porphyrin-encapsulated microbubbles to nanobubbles, with actively enhanced permeability for local delivery. This platform holds implications for optical/ultrasound-based imaging and therapeutics. While promising, it remains to be established how nanobubbles are generated and whether they extravasate intact. Here, insights into the conversion process are reported, complemented by novel simultaneous intravital and acoustic monitoring in tumor-affected functional circulation. The first direct acoustic evidence of extravascular intact nanobubbles are presented. These insights collectively advance this delivery platform and multimodal micro- and nanobubbles, extending their utility for imaging and therapeutics within and beyond the vasculature.

Fluorescent conjugated polymer nanovector for in vivo tracking and regulating the fate of stem cells for restoring infarcted myocardium

Stem cell therapy holds great promise for cardiac regeneration. However, the lack of ability to control stem cell fate after in vivo transplantation greatly restricts its therapeutic outcomes. MicroRNA delivery has emerged as a powerful tool to control stem cell fate for enhanced cardiac regeneration. However, the clinical translation of therapy based on gene-transfected stem cells remains challenging, due to the unknown in vivo behaviors of stem cells. Here, we developed a nano-platform (i.e., PFBT@miR-1-Tat NPs) that can achieve triggered release of microRNA-1 to promote cardiac differentiation of mesenchymal stem cells (MSCs), and long-term tracking of transplanted MSCs through bright and ultra-stable fluorescence of conjugated polymer poly(9,9-dioctylfluorene-alt-benzothiadiazole) (PFBT). We found that PFBT@miR-1-Tat NP-treated MSCs significantly restored the infarcted myocardium by promoting stem cell cardiac differentiation and integration with the in situ cardiac tissues. Meanwhile, MSCs without gene delivery improved the infarcted heart functions mainly through a paracrine effect and blood vessel formation. The developed conjugated polymer nanovector should be a powerful tool for manipulating as well as revealing the fate of therapeutic cells in vivo, which is critical for optimizing the therapeutic route of gene and cell combined therapy and therefore for accelerating clinical translation. STATEMENT OF SIGNIFICANCE: The lack of controllability in stem cell fate and the unclear in vivo cellular behaviors restrict the therapeutic outcomes of stem cell therapy. Herein, we engineered fluorescent conjugated polymer nanoparticles as gene delivery nanovectors with controlled release and high intracellular delivery capability to harness the fate of mesenchymal stem cells (MSCs) in vivo, meanwhile to reveal the cellular mechanism of gene-treated stem cell therapy. As compared with only MSC treatment that improves infarcted myocardium functions through paracrine effect, treatment with conjugated polymer nanovector-treated MSCs significantly restored infarcted myocardium through enhancing MSC cardiac differentiation and integration with the in-situ cardiac tissues. These findings demonstrate that the conjugated polymer nanovector would be a powerful tool in optimizing gene and cell combined therapy.

Recent progress in drug delivery

Drug delivery systems (DDS) are defined as methods by which drugs are delivered to desired tissues, organs, cells and subcellular organs for drug release and absorption through a variety of drug carriers. Its usual purpose to improve the pharmacological activities of therapeutic drugs and to overcome problems such as limited solubility, drug aggregation, low bioavailability, poor biodistribution, lack of selectivity, or to reduce the side effects of therapeutic drugs. During 2015-2018, significant progress in the research on drug delivery systems has been achieved along with advances in related fields, such as pharmaceutical sciences, material sciences and biomedical sciences. This review provides a concise overview of current progress in this research area through its focus on the delivery strategies, construction techniques and specific examples. It is a valuable reference for pharmaceutical scientists who want to learn more about the design of drug delivery systems.

pH-Responsive polyelectrolyte coated gadolinium oxide-doped mesoporous silica nanoparticles (Gd2O3@MSNs) for synergistic drug delivery and magnetic resonance imaging enhancement

Theranostic platforms that combine therapeutic and imaging modalities have received increasing interest.