Synergism of Nanomaterials with Physical Stimuli for Biology and Medicine

Engineering magnetic nanosystem for TRPV1 and TRPV4 channel activation

Recently, physical tools for remotely stimulating mechanical force-sensitive and temperature-sensitive proteins to regulate intracellular pathways have opened up novel and exciting avenues for basic research and clinical applications. Among the numerous modes of physical stimulation, magnetic stimulation is significantly attractive for biological applications due to the advantages of depth penetration and spatial-temporally controlled transduction. Herein, the physicochemical parameters (e.g., shape, size, composition) that influence the magnetic properties of magnetic nanosystems as well as the characteristics of transient receptor potential vanilloid-1 (TRPV1) and transient receptor potential vanilloid-4 (TRPV4) channels are systematically summarized, which offer opportunities for magnetic manipulation of cell fate in a precise and effective manner. In addition, representative regulatory applications involving magnetic nanosystem-based TRPV1 and TRPV4 channel activation are highlighted, both at the cellular level and in animal models. Furthermore, perspectives on the further development of this magnetic stimulation mode are commented on, with emphasis on scientific limitations and possible directions for exploitation. This article is categorized under: Diagnostic Tools > Biosensing Diagnostic Tools > In Vivo Nanodiagnostics and Imaging.

Biological Preparation of Chitosan-Loaded Silver Nanoparticles: Study of Methylene Blue Adsorption as Well as Antibacterial Properties under Light

Human beings have made significant progress in the medical field since antibiotics were widely used. However, the consequences caused by antibiotics abuse have gradually shown their negative effects. Antibacterial photodynamic therapy (aPDT) has the ability to resist drug-resistant bacteria without antibiotics, and as it is increasingly recognized that nanoparticles can effectively solve the deficiency problem of singlet oxygen produced by photosensitizers, the application performance and scope of aPDT are gradually being expanded. In this study, we used a biological template method to reduce Ag⁺ to silver atoms in situ with bovine serum albumin (BSA) rich in various functional groups in a 50 °C water bath. The aggregation of nanomaterials was inhibited by the protein's multistage structure so that the formed nanomaterials have good dispersion and stability. It is unexpected that we used chitosan microspheres (CMs) loaded with silver nanoparticles (AgNPs) to adsorb methylene blue (MB), which is both a pollutant and photosensitive substance. The Langmuir adsorption isothermal curve was used to fit the adsorption capacity. The exceptional multi-bond angle chelating forceps of chitosan make it have a powerful physical adsorption capacity, and dehydrogenated functional groups of proteins with negative charge can also bond to positively charged MB to form a certain amount of ionic bonds. Compared with single bacteriostatic materials, the bacteriostatic capacity of the composite materials adsorbing MB under light was significantly improved. This composite material not only has a strong inhibitory effect on Gram-negative bacteria but also has a good inhibitory effect on the growth of Gram-positive bacteria poorly affected by conventional bacteriostatic agents. In conclusion, the CMs loaded with MB and AgNPs have some possible applications in the purification or treatment of wastewater in the future.

Applications of synthetic biology in medical and pharmaceutical fields

Synthetic biology aims to design or assemble existing bioparts or bio-components for useful bioproperties. During the past decades, progresses have been made to build delicate biocircuits, standardized biological building blocks and to develop various genomic/metabolic engineering tools and approaches. Medical and pharmaceutical demands have also pushed the development of synthetic biology, including integration of heterologous pathways into designer cells to efficiently produce medical agents, enhanced yields of natural products in cell growth media to equal or higher than that of the extracts from plants or fungi, constructions of novel genetic circuits for tumor targeting, controllable releases of therapeutic agents in response to specific biomarkers to fight diseases such as diabetes and cancers. Besides, new strategies are developed to treat complex immune diseases, infectious diseases and metabolic disorders that are hard to cure via traditional approaches. In general, synthetic biology brings new capabilities to medical and pharmaceutical researches. This review summarizes the timeline of synthetic biology developments, the past and present of synthetic biology for microbial productions of pharmaceutics, engineered cells equipped with synthetic DNA circuits for diagnosis and therapies, live and auto-assemblied biomaterials for medical treatments, cell-free synthetic biology in medical and pharmaceutical fields, and DNA engineering approaches with potentials for biomedical applications.

Antimicrobial Properties of Silver-Modified Denture Base Resins

The surface quality of denture base resins allows for easy colonization by microorganisms including Candida albicans and Staphylococcus aureus, which cause major diseases of the oral cavity such as denture stomatitis. The widespread use of silver nanoparticles (AgNPs) in various fields of medicine has led to research of their possible application in dentistry, mostly in the prevention of bacterial adhesion, proliferation, and biofilm formation. The aim of the study was to synthesize cold and heat-curing denture base resins modified with AgNPs and AgCl, and evaluate the potential of the modified resins to reduce the growth of C. albicans and S.aureus. The produced material was characterized by Fourier transform infrared spectroscopy (FTIR). The antimicrobial potential of the modified material was demonstrated by the disc-diffusion method, microdilution method, and a modified microdilution method (i.e., disk-diffusion method in broth with viable counting). Spectroscopy confirmed the incorporation of biocidal materials into the structure of the denture base resins. The AgCl and AgNPs modified resins showed an antimicrobial effect. The significance of the study is in the potential therapeutic effects of the modified materials for prevention and threating staphylococci and candida in elderly patients, who are in most cases denture wearers and have a greater susceptibility to develop opportunistic infections. Modified denture base resins can significantly reduce the presence of infection at the point of contact between the denture and the mucous membrane of the prosthetic restoration. Biological tests of modified denture base resins will follow.

Biological interactions of ferromagnetic iron oxide-carbon nanohybrids with alveolar epithelial cells

Iron oxide nanoparticles (IONPs) have been largely investigated in a plethora of biological fields for their interesting physical-chemical properties, which make them suitable for application in cancer therapy, neuroscience, and imaging. Several encouraging results have been reported in these contexts. However, the possible toxic effects of some IONP formulations can limit their applicability. In this work, IONPs were synthesized with a carbon shell (IONP@C), providing enhanced stability both as colloidal dispersion and in the biological environment. We conducted a careful multiparametric evaluation of IONP@C biological interactions in vitro, providing them with an in vivo-like biological identity. Our hybrid nanoformulation showed no cytotoxic effects on a widely employed model of alveolar epithelial cells for a variety of concentrations and exposure times. The IONP@C were efficiently internalized and TEM analysis allowed the protective role of the carbon shell against intracellular degradation to be assessed. Intracellular redistribution of the IONP@C from the lysosomes to the lamellar bodies was also observed after 72 hours.

Origin of Metal Cluster Tuning Enzyme Activity at the Bio-Nano Interface

Detailed understanding of how the bio-nano interface orchestrates the function of both biological components and nanomaterials remains ambiguous. Here, through a combination of experiments and molecular dynamics simulations, we investigated how the interface between Candida Antarctic lipase B and palladium (Pd) nanoparticles (NPs) tunes the structure, dynamics, and catalysis of the enzyme. Our simulations show that the metal binding to protein is a shape matching behavior and there is a transition from saturated binding to unsaturated binding along with the increase in the size of metal NPs. When we engineered the interface with the polymer, not only did the critical size of saturated binding of metal NPs become larger, but also the disturbance of the metal NPs to the enzyme function was reduced. In addition, we found that an enzyme-metal interface engineered with the polymer can boost bio-metal cascade reactions via substrate channeling. Understanding and control of the bio-nano interface at the molecular level enable us to rationally design bio-nanocomposites with prospective properties.

Magnetogenetics: remote activation of cellular functions triggered by magnetic switches

During the last decade, the possibility to remotely control intracellular pathways using physical tools has opened the way to novel and exciting applications, both in basic research and clinical applications. Indeed, the use of physical and non-invasive stimuli such as light, electricity or magnetic fields offers the possibility of manipulating biological processes with spatial and temporal resolution in a remote fashion. The use of magnetic fields is especially appealing for in vivo applications because they can penetrate deep into tissues, as opposed to light. In combination with magnetic actuators they are emerging as a new instrument to precisely manipulate biological functions. This approach, coined as magnetogenetics, provides an exclusive tool to study how cells transform mechanical stimuli into biochemical signalling and offers the possibility of activating intracellular pathways connected to temperature-sensitive proteins. In this review we provide a critical overview of the recent developments in the field of magnetogenetics. We discuss general topics regarding the three main components for magnetic field-based actuation: the magnetic fields, the magnetic actuators and the cellular targets. We first introduce the main approaches in which the magnetic field can be used to manipulate the magnetic actuators, together with the most commonly used magnetic field configurations and the physicochemical parameters that can critically influence the magnetic properties of the actuators. Thereafter, we discuss relevant examples of magneto-mechanical and magneto-thermal stimulation, used to control stem cell fate, to activate neuronal functions, or to stimulate apoptotic pathways, among others. Finally, although magnetogenetics has raised high expectations from the research community, to date there are still many obstacles to be overcome in order for it to become a real alternative to optogenetics for instance. We discuss some controversial aspects related to the insufficient elucidation of the mechanisms of action of some magnetogenetics constructs and approaches, providing our opinion on important challenges in the field and possible directions for the upcoming years.

Biophysical Approaches for Applying and Measuring Biological Forces

Over the past decades, increasing evidence has indicated that mechanical loads can regulate the morphogenesis, proliferation, migration, and apoptosis of living cells. Investigations of how cells sense mechanical stimuli or the mechanotransduction mechanism is an active field of biomaterials and biophysics. Gaining a further understanding of mechanical regulation and depicting the mechanotransduction network inside cells require advanced experimental techniques and new theories. In this review, the fundamental principles of various experimental approaches that have been developed to characterize various types and magnitudes of forces experienced at the cellular and subcellular levels are summarized. The broad applications of these techniques are introduced with an emphasis on the difficulties in implementing these techniques in special biological systems. The advantages and disadvantages of each technique are discussed, which can guide readers to choose the most suitable technique for their questions. A perspective on future directions in this field is also provided. It is anticipated that technical advancement can be a driving force for the development of mechanobiology.

Biomimetic Hydroxyapatite Nanorods Promote Bone Regeneration via Accelerating Osteogenesis of BMSCs through T Cell-Derived IL-22

Manipulations of morphological properties of nanobiomaterials have been demonstrated to modulate the outcome of osteoimmunomodulation and eventually osteogenesis through innate immune response. However, the functions and mechanisms of adaptive immune cells in the process of nanobiomaterials-mediated bone regeneration have remained unknown. Herein, we developed bone-mimicking hydroxyapatite (HAp) nanorods with different aspect ratios as model materials to investigate the impacts of the nanoshape features on osteogenesis and to explore the underlying mechanisms focusing on the functions of T cells and T cell-derived cytokines. HAp nanorods with different aspect ratios (HAp-0, HAp-30, and HAp-100) were implanted into mouse mandibular defect models. Micro-CT and hematoxylin and eosin staining demonstrated that HAp-100 had the best osteogenic effects. Flow cytometry analysis revealed that HAp-100 increased the percentage of T cells in injured mandibles. The osteogenic effects of HAp-100 were significantly blunted in injured mandibles of TCRβ-/- mice. The Luminex xMAP assay and ELISA showed that HAp-100 induced a marked increase of interleukin (IL)-22 in injured mandibles. In cultured T cells, HAp-100 manifested the best capacity to induce the production of IL-22. Conditioned media from HAp-100-primed T cells promoted osteogenesis and JAK1/STAT3 activation in bone marrow stromal cells, all of which were abolished by neutralizing antibodies against IL-22. In summary, bone-mimicking HAp nanorods with different aspect ratios could regulate osteogenesis through modulation of T cells and IL-22 in the bone regeneration process. These findings provided insights for mediation of the immune response of T cells by nanomaterials on osteogenesis and strategies for designing biomaterials with osteoimmunomodulative functions.

Review of Noninvasive or Minimally Invasive Deep Brain Stimulation

Brain stimulation is a critical technique in neuroscience research and clinical application. Traditional transcranial brain stimulation techniques, such as transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS), and deep brain stimulation (DBS) have been widely investigated in neuroscience for decades. However, TMS and tDCS have poor spatial resolution and penetration depth, and DBS requires electrode implantation in deep brain structures. These disadvantages have limited the clinical applications of these techniques. Owing to developments in science and technology, substantial advances in noninvasive and precise deep stimulation have been achieved by neuromodulation studies. Second-generation brain stimulation techniques that mainly rely on acoustic, electronic, optical, and magnetic signals, such as focused ultrasound, temporal interference, near-infrared optogenetic, and nanomaterial-enabled magnetic stimulation, offer great prospects for neuromodulation. This review summarized the mechanisms, development, applications, and strengths of these techniques and the prospects and challenges in their development. We believe that these second-generation brain stimulation techniques pave the way for brain disorder therapy.

Magneto mitochondrial dysfunction mediated cancer cell death using intracellular magnetic nano-transducers

Mitochondria are crucial regulators of the intrinsic pathway of cancer cell death. The high sensitivity of cancer cells to mitochondrial dysfunction offers opportunities for emerging targets in cancer therapy. Herein, magnetic nano-transducers, which convert external magnetic fields into physical stress, are designed to induce mitochondrial dysfunction to remotely kill cancer cells. Spindle-shaped iron oxide nanoparticles were synthesized to maximize cellular internalization and magnetic transduction. The magneto-mechanical transduction of nano-transducers in mitochondria enhances cancer cell apoptosis by promoting a mitochondrial quality control mechanism, referred to as mitophagy. In the liver cancer animal model, nano-transducers are infused into the local liver tumor via the hepatic artery. After treatment with a magnetic field, in vivo mitophagy-mediated cancer cell death was also confirmed by mitophagy markers, mitochondrial DNA damage assay, and TUNEL staining of tissues. This study is expected to contribute to the development of nanoparticle-mediated mitochondria-targeting cancer therapy and biological tools, such as magneto-genetics.

Biomaterials-based approaches to model embryogenesis

Understanding, reproducing, and regulating the cellular and molecular processes underlying human embryogenesis is critical to improve our ability to recapitulate tissues with proper architecture and function, and to address the dysregulation of embryonic programs that underlies birth defects and cancer. The rapid emergence of stem cell technologies is enabling enormous progress in understanding embryogenesis using simple, powerful, and accessible in vitro models. Biomaterials are playing a central role in providing the spatiotemporal organisation of biophysical and biochemical signalling necessary to mimic, regulate and dissect the evolving embryonic niche in vitro. This contribution is rapidly improving our understanding of the mechanisms underlying embryonic patterning, in turn enabling the development of more effective clinical interventions for regenerative medicine and oncology. Here we highlight how key biomaterial approaches contribute to organise signalling in human embryogenesis models, and we summarise the biological insights gained from these contributions. Importantly, we highlight how nanotechnology approaches have remained largely untapped in this space, and we identify their key potential contributions.

Nanoparticle Delivery Systems with Cell-Specific Targeting for Pulmonary Diseases

Respiratory disorders are among the most important medical problems threatening human life. The conventional therapeutics for respiratory disorders are hindered by insufficient drug concentrations at pathological lesions, lack of cell-specific targeting, and various biobarriers in the conducting airways and alveoli. To address these critical issues, various nanoparticle delivery systems have been developed to serve as carriers of specific drugs, DNA expression vectors, and RNAs. The unique properties of nanoparticles, including controlled size and distribution, surface functional groups, high payload capacity, and drug release triggering capabilities, are tailored to specific requirements in drug/gene delivery to overcome major delivery barriers in pulmonary diseases. To avoid off-target effects and improve therapeutic efficacy, nanoparticles with high cell-targeting specificity are essential for successful nanoparticle therapies. Furthermore, low toxicity and high degradability of the nanoparticles are among the most important requirements in the nanoparticle designs. In this review, we provide the most up-to-date research and clinical outcomes in nanoparticle therapies for pulmonary diseases. We also address the current critical issues in key areas of pulmonary cell targeting, biosafety and compatibility, and molecular mechanisms for selective cellular uptake.

Current Limitations and Recent Progress in Nanomedicine for Clinically Available Photodynamic Therapy

Photodynamic therapy (PDT) using oxygen, light, and photosensitizers has been receiving great attention, because it has potential for making up for the weakness of the existing therapies such as surgery, radiation therapy, and chemotherapy. It has been mainly used to treat cancer, and clinical tests for second-generation photosensitizers with improved physicochemical properties, pharmacokinetic profiles, or singlet oxygen quantum yield have been conducted. Progress is also being made in cancer theranostics by using fluorescent signals generated by photosensitizers. In order to obtain the effective cytotoxic effects on the target cells and prevent off-target side effects, photosensitizers need to be localized to the target tissue. The use of nanocarriers combined with photosensitizers can enhance accumulation of photosensitizers in the tumor site, owing to preferential extravasation of nanoparticles into the tumor vasculature by the enhanced permeability and retention effect. Self-assembly of amphiphilic polymers provide good loading efficiency and sustained release of hydrophobic photosensitizers. In addition, prodrug nanomedicines for PDT can be activated by stimuli in the tumor site. In this review, we introduce current limitations and recent progress in nanomedicine for PDT and discuss the expected future direction of research.

Stimulus-responsive nanocarriers for targeted drug delivery

Cancer is a multifactorial disease that involves unique tumor microenvironment (TEM) and abnormal organs with complex structures.

Remote neurostimulation with physical fields at cellular level enabled by nanomaterials: Toward medical applications

Most neurological diseases have no cure today; innovations in neurotechnology are in urgent need. Nanomaterial-based remote neurostimulation with physical fields (NNSPs) is an emerging class of neurotechnologies that has generated tremendous interest in recent years. This perspective focuses on the clinical translation of this new class of neurotechnologies, an issue that so far has not received enough attention. We outline the major barriers in their clinical translation. We highlight our recent efforts to tackle these translational barriers, with a focus on the biological delivery problem. In particular, for the first time, we have shown that it is feasible to use noninvasive brain delivery to generate significant physiological responses in living animals by NNSP. However, much more work is needed to overcome the translational barriers.

Carbon Nanospheres Exert Antitumor Effects Associated with Downregulation of 4E-BP1 Expression on Prostate Cancer

Introduction

Although carbon nanospheres (CNPs) are promising nanomaterials in cancer treatment, how they affect prostate cancer (PCa) remains unclear.

Methods

In this study, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy were used to confirm the successful synthesis of CNPs. CCK-8, flow cytometry, Transwell, wound healing, Western blot and immunohistochemistry (IHC) assays were performed to evaluate the antitumor effect of CNPs toward the two kinds of prostate cancer cell lines PC3 and DU145.

Results

Our results showed that CNPs inhibited cell growth, invasion, and migration and induced apoptosis and autophagy in PCa cells. Multifactor detection of a single Akt phosphorylation pathway and Western blot results suggested the suppression of 4E-BP1 in PCa cells after incubation with CNPs. The results from animal experiments also suggested the antitumor effect of CNPs and reduced 4E-BP1 expression in PCa tissue samples from BALB/c nude mice administered a local subcutaneous injection of CNPs.

Engineering the Bio-Nano Interface Using a Multifunctional Coordinating Polymer Coating

In the past three decades, interest in using nanoparticles as diagnostic tools to interrogate various biosystems has witnessed remarkable growth. For instance, it has been shown that nanoparticle probes enable the study of cellular processes at the single molecule level. These advances provide new opportunities for understanding fundamental problems in biology, innovation in medicine, and the treatment of diseases. A multitude of nanoparticles have been designed to facilitate in vitro or in vivo sensing, imaging, and diagnostics. Some of those nanoparticle platforms are currently in clinical trials or have been approved by the U.S. Food and Drug Administration. Nonetheless, using nanoparticles in biology is still facing several obstacles, such as poor colloidal stability under physiological conditions, nonspecific interactions with serum proteins, and low targeting efficiency in biological fluids, in addition to issues of uncontrolled biodistribution and cytotoxicity. All these problems are primarily controlled by the surface stabilizing coating used.In this Account, we summarize recent progress made in our laboratory focused on the development of multifunctional polymers as coordinating ligands, to tailor the surface properties of nanoparticles and facilitate their application in biology. We first detail the advantageous features of the coating strategy, followed by a discussion of the key parameters in the ligand design. We then describe the synthesis and use of a series of multicoordinating polymers as ligands optimized for coating quantum dots (QDs), gold nanoparticles (AuNPs), and magnetic nanoparticles (MNPs), with a focus on (i) how to improve the colloidal stability and antifouling performance of materials in biological conditions; (ii) how to design highly compact coating, without compromising colloidal stability; and (iii) how to tailor the surface functionalities to achieve conjugation to target biomolecules. We also highlight the ability of a phase transfer strategy, mediated by UV irradiation, to promote rapid ligand exchange while preserving the integrity of key functional groups. We then summarize the bioconjugation approaches applied to polymer-coated nanoparticles, with emphasis on the ability of metal-histidine self-assembly and click chemistry, to control the final nanoparticle bioconjugates. Finally, we demonstrate the use of polymer-coated nanoparticles for sensor design based on redox-active interactions and peptide-mediated intracellular delivery. We anticipate that the coating design presented in this Account would advance the integration of nanoparticles into biology and medicine.

Programmable ROS-Mediated Cancer Therapy via Magneto-Inductions

Reactive oxygen species (ROS), a group of oxygen derived radicals and derivatives, can induce cancer cell death via elevated oxidative stress. A spatiotemporal approach with safe and deep-tissue penetration capabilities to elevate the intracellular ROS level is highly desirable for precise cancer treatment. Here, a mechanical-thermal induction therapy (MTIT) strategy is developed for a programmable increase of ROS levels in cancer cells via assembly of magnetic nanocubes integrated with alternating magnetic fields. The magneto-based mechanical and thermal stimuli can disrupt the lysosomes, which sequentially induce the dysfunction of mitochondria. Importantly, intracellular ROS concentrations are responsive to the magneto-triggers and play a key role for synergistic cancer treatment. In vivo experiments reveal the effectiveness of MTIT for efficient eradication of glioma and breast cancer. By remote control of the force and heat using magnetic nanocubes, MTIT is a promising physical approach to trigger the biochemical responses for precise cancer treatment.

Engineered iron oxide nanoparticles to improve regenerative effects of mesenchymal stem cells

Abstract

Mesenchymal stem cells (MSCs) based therapies are a major field of regenerative medicine. However, the success of MSC therapy relies on the efficiency of its delivery and retention, differentiation, and secreting paracrine factors at the target sites. Recent studies show that superparamagnetic iron oxide nanoparticles (SPIONs) modulate the regenerative effects of MSCs. After interacting with the cell membrane of MSCs, SPIONs can enter the cells via the endocytic pathway. The physicochemical properties of nanoparticles, including size, surface charge (zeta-potential), and surface ligand, influence their interactions with MSC, such as cellular uptake, cytotoxicity, homing factors, and regenerative related factors (VEGF, TGF-β1). Therefore, in-depth knowledge of the physicochemical properties of SPIONs might be a promising lead in regenerative and anti-inflammation research using SPIONs mediated MSCs. In this review, recent research on SPIONs with MSCs and the various designs of SPIONs are examined and summarized.

Graphic abstract

A graphical abstract describes important parameters in the design of superparamagnetic iron oxide nanoparticles, affecting mesenchymal stem cells. These physicochemical properties are closely related to the mesenchymal stem cells to achieve improved cellular responses such as homing factors and cell uptake.

"Off/on" fluorescence imaging-guided cancer diagnosis and multi-modal therapy

An efficient theranostic nanoplatform responding to tumour microenvironments with characters of simple and flexible combinations owns great potential in cancer diagnosis and therapy. Herein, a series of triblock copolymers, mPEG-b-PDPA-b-P(nBMA-r-cystamine) (EPB), were synthesized and among them, the structure of EPB-3 was optimized for both fluorescence imaging-guided cancer diagnosis and multi-modal therapy with good biocompatibility. (1) The self-assembled nanoparticles of EPB-3-ICG₁ obtained by conjugating one ICG on EPB-3 via S-S bonds effectively performed reduction-sensitive OFF/ON fluorescence signal transition, thus inducing tumour cell-specific amplified fluorescence imaging in vitro and in vivo. (2) By entrapping Au nanorods into the co-assembled NPs of EPB-3 and EPB-3-ICG₁, EPB-3-ICG₁@Au NPs could synchronously induce strong tumour fluorescence imaging and high local photothermal effect, indicating the potential of imagine-guided photothermal therapy. (3) EPB-3 NPs could efficiently co-load paclitaxel (PTX) and ICG to form stable EPB-3@PTX@ICG NPs, which provided long periods of intracellular pH-sensitive sustainable drug release and highly enhanced apoptosis of 4T1 cells in vitro by the chemo-photothermal effect. Excitingly, a single intravenous injection of EPB-3@PTX@ICG NPs followed by a one-time local near-infrared light (NIR, 808 nm) irradiation treatment for 10 min could lead to significant inhibition of tumour growth, avoiding tumor metastasis and extending the survival of mice. All the above-mentioned results suggest that EPB-3 provides a nanoplatform with the characters of simple structure, convenience of use and flexible combination, holding potential for multi-modal diagnosis and therapy.

New Immunosensing-Fluorescence Detection of Tumor Marker Cytokeratin-19 Fragment (CYFRA 21-1) Via Carbon Quantum Dots/Zinc Oxide Nanocomposite

The rapid detection of lung cancer in early stages using the antigen cytokeratin-19 fragment (CYFRA 21-1) as a tumor marker in human serum plays an important role in the survival of patients and taking a fast surgical reaction. This study aimed to employ the green synthesized carbon quantum dots conjugated zinc oxide nanocomposite as a highly sensitive fluorescence immunosensing solution for fast determination of CYFRA 21-1 antigen in human serum. The suggested method was conducted by applying a hydrothermal method to prepare carbon quantum dots using Citrus lemon pericarp. The formed carbon quantum dots were used in the reduction and stabilization of zinc acetate to synthesize carbon quantum dots-zinc oxide nanocomposite. To form a sandwich capping antibody-antigen-antibody immunosensing system, a CYFRA 21-1 antigen was trapped by immobilizing a non-conjugated monoclonal antibody BM 19.21 on the surface of carbon quantum dots-zinc oxide nanocomposite and another monoclonal antibody KS 19.1, which was coated on the microtiter well surface. This system has a tunable fluorescence feature recorded at excitation and emission of λex = 470 and λem = 520 nm, respectively. The suggested nanocomposite fluorescence immunosensing system displayed a linear relationship of 0.01-100 ng mL-1 with a limit of detection of 0.008 ng mL-1. The suggested immunosensing system based on carbon quantum dots-zinc oxide nanocomposite provides a promising approach for rapid diagnoses of lung cancer by detecting CYFRA 21-1 in human serum.

Remote Control of Mechanical Forces via Mitochondrial-Targeted Magnetic Nanospinners for Efficient Cancer Treatment

In cells, mechanical forces play a key role in impacting cell behaviors, including adhesion, differentiation, migration, and death. Herein, a 20 nm mitochondria-targeted zinc-doped iron oxide nanocube is designed as a nanospinner to exert mechanical forces under a rotating magnetic field (RMF) at 15 Hz and 40 mT to fight against cancer. The nanospinners can efficiently target the mitochondria of cancer cells. By means of the RMF, the nanocubes assemble in alignment with the external field and produce a localized mechanical force to impair the cancer cells. Both in vitro and in vivo studies show that the nanospinners can damage the cancer cells and reduce the brain tumor growth rate after the application of the RMF. This nanoplatform provides an effective magnetomechanical approach to treat deep-seated tumors in a spatiotemporal fashion.

Tumor-triggered personalized microRNA cocktail therapy for hepatocellular carcinoma

miRNA cocktail therapy based on pH-responsive nanoparticles featuring PEG detachment and size transformation is a potential strategy for HCC treatment.

Enhancing the effects of transcranial magnetic stimulation with intravenously injected magnetic nanoparticles

Transcranial magnetic stimulation (TMS) is a non-invasive and clinically approved method for treating neurological disorders. However, the relatively weak intracranial electric current induced by TMS is an obvious inferiority which can only produce limited treatment effects in clinical application. The present study aimed to investigate the possibility of enhancing the effects of TMS with intravenously administrated magnetic nanoparticles. To facilitate crossing of the blood-brain barrier (BBB), the superparamagnetic iron oxide nanoparticles (SPIONs) were coated with carboxylated chitosan and poly(ethylene glycol). To aid the nanoparticles in crossing the BBB and targeting the predesigned brain regions, an external permanent magnet was attached to the foreheads of the rats before the intravenous administration of SPIONs. The electrophysiological tests showed that the maximum MEP amplitude recorded in an individual rat was significantly higher in the SPIONs + magnet group than in the saline group (5.78 ± 2.54 vs. 1.80 ± 1.55 mV, P = 0.015). In the M1 region, biochemical tests detected that the number density of c-fos positive cells in the SPIONs + magnet group was 3.44 fold that of the saline group. These results suggest that intravenously injected SPIONs can enhance the effects of TMS in treating neurological disorders.

Magnetic Control of Axon Navigation in Reprogrammed Neurons

While neural cell transplantation represents a promising therapy for neurodegenerative diseases, the formation of functional networks of transplanted cells with host neurons constitutes one of the challenging steps. Here, we introduce a magnetic guidance methodology that controls neurite growth signaling via magnetic nanoparticles (MNPs) conjugated with antibodies targeting the deleted in colorectal cancer (DCC) receptor (DCC-MNPs). Activation of the DCC receptors by clusterization and subsequent axonal growth of the induced neuronal (iN) cells was performed in a spatially controlled manner. In addition to the directionality of the magnetically controlled axon projection, axonal growth of the iN cells assisted the formation of functional connections with pre-existing primary neurons. Our results suggest magnetic guidance as a strategy for improving neuronal connectivity by spatially guiding the axonal projections of transplanted neural cells for synaptic interactions with the host tissue.

Antimicrobial Gold Nanoclusters: Recent Developments and Future Perspectives

Bacterial infections have caused serious threats to public health due to the antimicrobial resistance in bacteria. Recently, gold nanoclusters (AuNCs) have been extensively investigated for biomedical applications because of their superior structural and optical properties. Great efforts have demonstrated that AuNCs conjugated with various surface ligands are promising antimicrobial agents owing to their high biocompatibility, polyvalent effect, easy modification and photothermal stability. In this review, we have highlighted the recent achievements for the utilizations of AuNCs as the antimicrobial agents. We have classified the antimicrobial AuNCs by their surface ligands including small molecules (< 900 Daltons) and macromolecules (> 900 Daltons). Moreover, the antimicrobial activities and mechanisms of AuNCs have been introduced into two main categories of small molecules and macromolecules, respectively. In accordance with the advancements of antimicrobial AuNCs, we further provided conclusions of current challenges and recommendations of future perspectives of antimicrobial AuNCs for fundamental researches and clinical applications.

Solution growth of 1D zinc tungstate (ZnWO4) nanowires; design, morphology, and electrochemical sensor fabrication for selective detection of chloramphenicol

Development of 1D nanostructures with novel morphology is a recent scientific attraction, so to say yielding unusual materials for advanced applications. In this work, we have prepared solution grown, single-pot 1D ZnWO₄ nanowires (NWs) and the morphology is assessed for label-free but selective detection of chloramphenicol. This is the first report where, such structures are being investigated for this purpose. Transmission electron microscopy shows the presence of strands of ZnWO₄ of about 20 nm in diameter. The formed NWs were highly dispersed in nature with uniform size and shape. X-ray diffraction analysis confirmed high purity of the designed NWs despite solution synthesis. X-ray photoelectron spectroscopy confirmed surface valence state of ZnWO₄. Fourier transform infrared spectroscopy was employed for the ascription of functional groups, whereas, optical properties were investigated using photoluminescence. NWs were employed for the detection of a model antibiotic, chloramphenicol. The developed sensor exhibited excellent limit of detection, 0.32 μM and 100% specificity as compared to its structural and functional analogues such as thiamphenicol and clindamycin. This work can broaden new opportunities for the researchers to explore unconventional nanomaterials bearing unique morphologies and quantum phenomenon for the label-free detection of other bioanalytes.

Controlled Nano-Bio Interface of Functional Nanoprobes for in Vivo Monitoring Enzyme Activity in Tumors

Engineering inorganic nanoparticles with a biocompatible shell to improve their physicochemical properties is a vital step in taking advantage of their superior magnetic, optical, and photothermal properties as multifunctional molecular imaging probes for disease diagnosis and treatment. The grafting/peeling-off strategy we developed for nanoparticle surface coating can fully control the targeting capability of functional nanoprobes by changing their colloidal behaviors such as diffusion and sedimentation rates at the desired sites. We demonstrated that a cleavable coating layer initially immobilized on the surface of magnetic resonance imaging probes not only makes the nanoparticles water-soluble but also can be selectively removed by specific enzymes, thereby resulting in a significant decrease of their water solubility in an enzyme-rich environment. Upon removal of surface coating, the changes in hydrodynamic size and surface charges of nanoprobes as a result of interacting with biomolecules and proteins lead to dramatic changes in their in vivo colloidal behaviors ( i. e., slow diffusion rates, tendency to aggregate and precipitate), which were quantitatively evaluated by examining changes in their hydrodynamic sizes, magnetic properties, and count rates during the size measurement. Because the retention time of nanoprobes within the tumor tissues depends on the uptake and excretion rate of the nanoprobes through the tumors, selective activation of nanoprobes by a specific enzyme resulted in much higher tumor accumulation and longer retention time within the tumors than that of the inactive nanoprobes, which passively passed through the tumors. The imaging contrast effect of tumors using activatable nanoprobes was significantly improved over using inactive probes. Therefore, the grafting/peeling-off strategy, as a general design approach for surface modification of nanoprobes, offers a promising and highly efficient way to render the nanoparticles suitable for targeted imaging of tumors.

Repolarization of myeloid derived suppressor cells via magnetic nanoparticles to promote radiotherapy for glioma treatment

Although radiotherapy has been established as a major therapeutic modality for glioma, radical new avenues are critically needed to prevent inevitable tumor recurrence. Herein, we utilized a magnetic nanoparticle-based platform with cationic polymer modification to promote radiotherapy for glioma treatment. We found that the nanoplatform induced cytotoxicity to glioma cells under radiation as well as promoting significant survival benefits in both immunocompetent and aythmic mice with glioma. Utilizing the magnetic properties of the nanoparticles, we were able to ascertain that myeloid derived suppressor cells (MDSC) were taking up nanoparticles in the brain tumor. The observed efficacy was attributed to destruction of glioma cells as well as MDSCs repolarization from immunosuppressive phenotype to a pro-inflammatory phenotype, which promoted antitumor effects and synergistically promoted radio-therapeutic effects. Our nanoparticles provide a robust dual-targeting platform for glioma radiotherapy by simultaneous eradication of tumor cells and manipulation of myeloid phenotypes in the central nervous system.

Theranostic Nanosystems for Targeted Cancer Therapy

Nanomaterials have revolutionized cancer imaging, diagnosis, and treatment. Multifunctional nanoparticles in particular have been designed for targeted cancer therapy by modulating their physicochemical properties to be delivered to the target and activated by internal and/or external stimuli. This review will focus on the fundamental "chemical" design considerations of stimuli-responsive nanosystems to achieve favorable tumor targeting beyond biological barriers and, furthermore, enhance targeted cancer therapy. In addition, we will summarize innovative smart nanosystems responsive to external stimuli (e.g., light, magnetic field, ultrasound, and electric field) and internal stimuli in the tumor microenvironment (e.g., pH, enzyme, redox potential, and oxidative stress).

Tumor-Acidity-Cleavable Maleic Acid Amide (TACMAA): A Powerful Tool for Designing Smart Nanoparticles To Overcome Delivery Barriers in Cancer Nanomedicine

Over the past few decades, cancer nanomedicine has been under intensive development for applications in drug delivery, cancer therapy, and molecular imaging. However, there exist a series of complex biological barriers in the path of a nanomedicine from the site of administration to the site of action. These barriers considerably prevent a nanomedicine from reaching its targets in a sufficient concentration and thus severely limit its therapeutic benefits. According to the delivery process, these biological delivery barriers can be briefly summarized in the following order: blood circulation, tumor accumulation, tumor penetration, cellular internalization, and intracellular drug release. The therapeutic effect of a nanomedicine is strongly determined by its ability to overcome these barriers. However, advances in cancer biology have revealed that each barrier has its own distinct microenvironment, which imposes different requirements on the optimal design of nanocarriers, thus further complicating the delivery process. For example, the pH of blood is neutral, while the tumor extracellular environment features an acidic pH (pH_e ≈ 6.5-7.0) and the endosome and lysosome are more acidic (pH 5.5-4.5). The nanoparticles (NPs) should be able to change their properties to adapt to each individual environment for robust and effective delivery. This demand promotes the design and development of smart delivery carriers that can respond to endogenous and exogenous stimuli. It is well-documented that tumors develop acidic extracellular microenvironments with pH ≈ 6.5-7.0 due to their abnormal metabolism in comparison with normal tissues. This provides a unique tool for designing smart NP drug delivery systems. Our studies have revealed that the NPs' physiochemical properties, such as particle size and surface charge, have profound effects on their systemic transport in the body. In different delivery stages, the NPs should possess different sizes or surface charges for optimal performance. We developed a class of stimuli-responsive NPs by incorporating tumor-acidity-cleavable maleic acid amide (TACMAA) as a design feature. TACMAA is produced by the facile reaction of an amino group with 2,3-dimethylmaleic anhydride (DMMA) and its derivatives and can be cleaved under tumor acidity. By virtue of such characteristics, NPs containing TACMAA enable size or surface charge switching at tumor sites so that they can overcome those delivery barriers for improved drug delivery and cancer therapy. In this Account, we systemically review the development and evolution of TACMAA-based delivery systems and elaborate how TACMAA helps the innovation and design of intelligent nanocarriers for overcoming the delivery barriers. In particular, our Account focuses on five parts: TACMAA chemistry, tumor-acidity-triggered charge reversal, tumor-acidity-triggered shell detachment, tumor-acidity-triggered size transition, and tumor-acidity-triggered ligand reactivation. We provide detailed information on how tumor-acidity-triggered property changes correlate with the ability of NPs to overcome delivery barriers.

Biophysical, bioinformatical, cellular, and molecular investigations on the effects of graphene oxide nanosheets on the hemoglobin structure and lymphocyte cell cytotoxicity

BACKGROUND

Implementations of nanoparticles have been receiving great interest in medicine and technology due to their unique characteristics. However, their toxic impacts on the biological system are not well explored.

AIM

This study aims to investigate the influence of fabricated nano graphene oxide (NGO) sheets on the secondary and quaternary structural alterations of human hemoglobin (Hb) and cytotoxicity against lymphocyte cells.

MATERIALS AND METHODS

Different spectroscopic methods, such as extrinsic and synchronous fluorescence spectroscopy and far circular dichroism (CD) spectroscopy, molecular docking investigation, cellular assays (trypan blue exclusion, cellular uptake, ROS, cell cycle, and apoptosis), and molecular assay (fold changes in anti/proapoptotic genes [B-cell lymphoma-2 {BCL2}/BAX] expression levels) were used in this study.

RESULTS

Transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and zeta potential investigations revealed the nano-sized nature of NGOs with good colloidal stability. Extrinsic fluorescence spectroscopy by using 8-anilinonaphthalene-1 -sulfonic acid and synchronous fluorescence spectroscopy showed that NGOs can unfold the quaternary structure of Hb in the vicinity of Tyr residues. The CD investigation demonstrated that the α-helicity of Hb experienced substantial alteration upon interaction with increasing concentrations of NGOs. The molecular docking study showed that NGOs interacted with polar residues of Hb. Cellular and molecular assays revealed that NGOs lead to ROS formation, cell cycle arrest, and apoptosis through the BAX and BCL2 pathway.

CONCLUSION

These data reveal that NGOs can induce some protein structural changes and stimulate cytotoxicity against normal cell targets. Therefore, their applications in healthy systems should be limited.

Carbon Nanomaterials for Treating Osteoporotic Vertebral Fractures

PURPOSE OF REVIEW

To identify the use of carbon nanomaterials in bone regeneration and present new data on the regenerative capacity of bone tissue in osteopenic rats treated with graphene nanoribbons (GNRs).

RECENT FINDINGS

The results show that the physical and chemical properties of the nanomaterials are suitable for the fabrication of scaffolds intended for bone regeneration. The in vitro tests suggested a non-toxicity of the GNRs as well as improved biocompatibility and bone mineralization activity. Here, for the first time, we evaluated the potential of GNRs in remodeling and repairing bone defects in osteoporotic animal models in vivo. Interestingly, bone mineralization and the initiation of the remodeling cycle by osteoclasts/osteoblasts were observed after the implantation of GNRs, thus implying healthy bone remodeling when using GNRs. This study, therefore, has opened our perspectives and certainly calls for more attention to the use of carbon nanomaterials for a wide range of osteoporosis applications.

CA 19-9 Pancreatic Tumor Marker Fluorescence Immunosensing Detection via Immobilized Carbon Quantum Dots Conjugated Gold Nanocomposite

The clinical detection of carbohydrate antigen 19-9 (CA 19-9), a tumor marker in biological samples, improves and facilitates the rapid screening and diagnosis of pancreatic cancer. A simple, low cost, fast, and green synthesis method to prepare a viable carbon quantum dots/gold (CQDs/Au) nanocomposite fluorescence immunosensing solution for the detection of CA 19-9 was reported. The present method is conducted by preparing glucose-derived CQDs using a microwave-assisted method. CQDs were employed as reducing and stabilizing agents for the preparation of a CQDs/Au nanocomposite. The immobilized anti-CA 19-9-labeled horseradish peroxidase enzyme (Ab-HRP) was anchored to the surface of a CQDs/Au nanocomposite by a peptide interaction between the carboxylic and amine active groups. The CA 19-9 antigen was trapped by another monoclonal antibody that was coated on the surface of microtiter wells. The formed sandwich capping antibody-antigen-antibody enzyme complex had tunable fluorescence properties that were detected under excitation and emission wavelengths of 420 and 530 nm. The increase in fluorescence intensities of the immunoassay sensing solution was proportional to the CA 19-9 antigen concentration in the linear range of 0.01-350 U mL-1 and had a lower detection limit of 0.007 U mL-1. The proposed CQDs/Au nanocomposite immunoassay method provides a promising tool for detecting CA 19-9 in human serum.

Nanomaterials for Cancer Precision Medicine

Medical science has recently advanced to the point where diagnosis and therapeutics can be carried out with high precision, even at the molecular level. A new field of "precision medicine" has consequently emerged with specific clinical implications and challenges that can be well-addressed by newly developed nanomaterials. Here, a nanoscience approach to precision medicine is provided, with a focus on cancer therapy, based on a new concept of "molecularly-defined cancers." "Next-generation sequencing" is introduced to identify the oncogene that is responsible for a class of cancers. This new approach is fundamentally different from all conventional cancer therapies that rely on diagnosis of the anatomic origins where the tumors are found. To treat cancers at molecular level, a recently developed "microRNA replacement therapy" is applied, utilizing nanocarriers, in order to regulate the driver oncogene, which is the core of cancer precision therapeutics. Furthermore, the outcome of the nanomediated oncogenic regulation has to be accurately assessed by the genetically characterized, patient-derived xenograft models. Cancer therapy in this fashion is a quintessential example of precision medicine, presenting many challenges to the materials communities with new issues in structural design, surface functionalization, gene/drug storage and delivery, cell targeting, and medical imaging.

Magnetic domain interactions of Fe3O4 nanoparticles embedded in a SiO2 matrix

Currently, superparamagnetic functionalized systems of magnetite (Fe₃O₄) nanoparticles (NPs) are promising options for applications in hyperthermia therapy, drug delivery and diagnosis. Fe₃O₄ NPs below 20 nm have stable single domains (SSD), which can be oriented by magnetic field application. Dispersion of Fe₃O₄ NPs in silicon dioxide (SiO₂) matrix allows local SSD response with uniaxial anisotropy and orientation to easy axis, 90° <001> or 180° <111>. A successful, easy methodology to produce Fe₃O₄ NPs (6-17 nm) has been used with the Stöber modification. NPs were embedded in amorphous and biocompatible SiO₂ matrix by mechanical stirring in citrate and tetraethyl orthosilicate (TEOS). Fe₃O₄ NPs dispersion was sampled in the range of 2-12 h to observe the SiO₂ matrix formation as time function. TEM characterization identified optimal conditions at 4 h stirring for separation of SSD Fe₃O₄ in SiO₂ matrix. Low magnetization (M_s) of 0.001 emu and a coercivity (H_c) of 24.75 Oe indicate that the embedded SSD Fe₃O₄ in amorphous SiO₂ reduces the M_s by a diamagnetic barrier. Magnetic force microscopy (MFM) showed SSD Fe₃O₄ of 1.2 nm on average embedded in SiO₂ matrix with uniaxial anisotropy response according to Fe³⁺ and Fe²⁺ electron spin coupling and rotation by intrinsic Neél contribution.

Design of Magnetically Labeled Cells (Mag-Cells) for in Vivo Control of Stem Cell Migration and Differentiation

Cell-based therapies are attractive for treating various degenerative disorders and cancer but delivering functional cells to the region of interest in vivo remains difficult. The problem is exacerbated in dense biological matrices such as solid tissues because these environments impose significant steric hindrances for cell movement. Here, we show that neural stem cells transfected with zinc-doped ferrite magnetic nanoparticles (ZnMNPs) can be pulled by an external magnet to migrate to the desired location in the brain. These magnetically labeled cells (Mag-Cells) can migrate because ZnMNPs generate sufficiently strong mechanical forces to overcome steric hindrances in the brain tissues. Once at the site of lesion, Mag-Cells show enhanced neuronal differentiation and greater secretion of neurotrophic factors than unlabeled control stem cells. Our study shows that ZnMNPs activate zinc-mediated Wnt signaling to facilitate neuronal differentiation. When implemented in a rodent brain stroke model, Mag-Cells led to significant recovery of locomotor performance in the impaired limbs of the animals. Our findings provide a simple magnetic method for controlling migration of stem cells with high therapeutic functions, offering a valuable tool for other cell-based therapies.

Toxicity of engineered nanomaterials mediated by nano-bio-eco interactions

Engineered nanomaterials may adversely impact human health and environmental safety by nano-bio-eco interactions not fully understood. Their interaction with biotic and abiotic environments are varied and complicated, ranging from individual species to entire ecosystems. Their behavior, transport, fate, and toxicological profiles in these interactions, addressed in a pioneering study, are subsequently seldom reported. Biological, chemical, and physical dimension properties, the so-called multidimensional characterization, determine interactions. Intermediate species generated in the dynamic process of nanomaterial transformation increase the complexity of assessing nanotoxicity. We review recent progress in understanding these interactions, discuss the challenges of the study, and suggest future research directions.

New label-free ultrasensitive electrochemical immunosensor-based Au/MoS2/rGO nanocomposites for CA 27-29 breast cancer antigen detection

Early diagnosis and clinical treatments of breast cancer provide a highly successful chance for patients to survive.

Magnetic Nanotransducers in Biomedicine

Owing to their abilities to identify diseased conditions, to modulate biological processes, and to control cellular activities, magnetic nanoparticles have become one of the most popular nanomaterials in the biomedical field. Targeted drug delivery, controlled drug release, hyperthermia treatment, imaging, and stimulation of several biological entities are just some of the several tasks that can be accomplished by taking advantage of magnetic nanoparticles in tandem with magnetic fields. The huge interest towards this class of nanomaterials arises from the possibility to physically drive their spatiotemporal localization inside the body, and to deliver an externally applied stimulation at a target site. They in fact behave as actual nanotransducers, converting energy stemming from the external magnetic field into heat and mechanical forces, which act as signals for therapeutic processes such as hyperthermia and controlled drug release. Magnetic nanoparticles are a noninvasive tool that enables the remote activation of biological processes, besides behaving as formidable tracers for different imaging modalities, thus allowing to simultaneously carry out diagnosis and therapy. In view of all this, owing to their multifunctional and multitasking nature, magnetic nanoparticles are already one of the most important nanotechnological protagonists in medicine and biology, enabling an actual theranostic approach in many pathological conditions. In this Concept, we first provide a brief introduction on some physical properties of magnetic materials and on important features that determine the physical properties of magnetic nanoparticles. Thereafter, we will consider some major biomedical applications: hyperthermia, drug delivery/release, and nanoparticle-mediated control of biological processes, even at subcellular level.