pH-triggered release of manganese from MnAu nanoparticles that enables cellular neuronal differentiation without cellular toxicity

Synergic effects of core-shell nanospheres and magnetic field for sciatic nerve regeneration in decellularized artery conduits with Schwann cells

Numerous conduits have been developed to improve peripheral nerve regeneration. However, challenges remain, including remote control of conduit function, and programmed cell behaviors like orientation. We synthesized Fe3O4-MnO2@Zirconium-based Metal-organic frameworks@Retinoic acid (FMZMR) core-shell and assessed their impact on Schwann cell function and behavior within conduits made from decellularized human umbilical arteries (DHUCA) under magnetic field (MF). FMZMR core-shell, featuring a spherical porous structure and catalytic properties, effectively scavenges radicals and facilitates controlled drug release under MF. The histology of the DHUCA indicates effective decellularization with adequate tensile strength and Young's modulus for sciatic nerve regeneration. In-vitro results demonstrate that FMZMR core-shell is biocompatible and promotes Schwann cell proliferation through remotely controlled drug release. Furthermore, its synergy with MF enhances cell orientation and increases neurite length by ~ 1.93-fold. Functional and histological evaluations indicate that the FMZMR core-shell combined with MF promotes nerve regeneration, decreases muscle atrophy, and enhances new neuron growth and myelin formation, without negatively affecting vital tissues. This study suggests that the synergistic effect of FMZMR core-shell with MF can alleviate some of the treatment challenges.

pH/glutathione-responsive theranostic nanoprobes for chemoimmunotherapy and magnetic resonance imaging of ovarian cancer cells

The integration of immunotherapy and standard chemotherapy holds great promise for enhanced anticancer effects. In this study, we prepared a pH- and glutathione (GSH)-sensitive manganese-doped mesoporous silicon (MMSNs) based drug delivery system by integrating paclitaxel (PTX) and anti-programmed cell death-ligand 1 antibody (aPD-L1), and encapsulating with polydopamine (PDA) for chemoimmunosynergic treatment of ovarian cancer cells. The nanosystem was degraded in response to the tumor weakly acidic and reductive microenvironment. The Mn2+ produced by degradation can be used as a contrast agent for magnetic resonance (MR) imaging to provide visual exposure to tumor tissue. The released PTX can not only kill tumor cells directly, but also induce immunogenic death (ICD) of tumor cells, which can play a synergistic therapeutic effect with aPD-L1. Therefore, our study is expected to provide a promising strategy for improving the efficacy of cancer immunotherapy and the detection rate of cancer.

Metal-Chelating Self-Assembling Peptide Nanofiber Scaffolds for Modulation of Neuronal Cell Behavior

Synthetic peptides are promising structural and functional components of bioactive and tissue-engineering scaffolds. Here, we demonstrate the design of self-assembling nanofiber scaffolds based on peptide amphiphile (PA) molecules containing multi-functional histidine residues with trace metal (TM) coordination ability. The self-assembly of PAs and characteristics of PA nanofiber scaffolds along with their interaction with Zn, Cu, and Mn essential microelements were studied. The effects of TM-activated PA scaffolds on mammalian cell behavior, reactive oxygen species (ROS), and glutathione levels were shown. The study reveals the ability of these scaffolds to modulate adhesion, proliferation, and morphological differentiation of neuronal PC-12 cells, suggesting a particular role of Mn(II) in cell-matrix interaction and neuritogenesis. The results provide a proof-of-concept for the development of histidine-functionalized peptide nanofiber scaffolds activated with ROS- and cell-modulating TMs to induce regenerative responses.

Gold Nanoparticles Reduce Food Sensation in Caenorhabditis elegans via the Voltage-Gated Channel EGL-19

Introduction

The increasing use of gold nanoparticles (Au NPs) in the medical field has raised concerns about the potential adverse effect of Au NPs exposure. However, it is difficult to assess the health risks of Au NPs exposure at the individual organ level using current measurement techniques.

Methods

The physical and chemical properties of Au NPs were characterized by transmission electron microscope (TEM), Fourier transform infrared (FTIR), and zeta sizer. The RNA-seq data of Au NPs-exposed worms were analyzed. The food intake was measured by liquid culture and Pharyngeal pumping rate. The function of the smell and taste neurons was evaluated by the chemotaxis and avoidance assay. The activation of ASE neurons was analyzed by calcium imaging. The gene expression of ins-22 and egl-19 was obtained from the C. elegans single cell RNA-seq databases.

Results

Our data analysis indicated that 62.8% of the significantly altered genes were functional in the nervous system. Notably, developmental stage analysis demonstrated that exposure to Au NPs interfered with animal development by regulating foraging behavior. Also, our chemotaxis results showed that exposure to Au NPs reduced the sensation of C. elegans to NaCl, which was consistent with the decrease in calcium transit of ASEL. Further studies confirmed that the reduced calcium transit was dependent on voltage-gated calcium channel EGL-19. The neuropeptide INS-22 was partially involved in Au NPs-induced NaCl sensation defect. Therefore, we proposed that Au NPs reduced the calcium transit in the ASEL neuron through egl-19-dependent calcium channels. It was partially regulated by the DAF-16 targeting neuropeptide INS-22.

Discussion

Our results demonstrate that Au NPs affect food sensation by reducing the calcium transit in ASEL neurons, which further leads to reduced pharynx pumping and feeding defects. The toxicology studies of Au NPs from worms have great potential to guide the usage of Au NPs in the medical field such as targeted drug delivery.

Exploring the Physicochemical, Electroactive, and Biodelivery Properties of Metal Nanoparticles on Peripheral Nerve Regeneration

Despite the advances in the regeneration/rehabilitation field of damaged tissues, the functional recovery of peripheral nerves (PNs), especially in a long gap injury, is considered a great medical challenge. Recent progress in nanomedicine has provided great hope for PN regeneration through the strategy of controlling cell behavior by metal nanoparticles individually or loaded on scaffolds/conduits. Despite the confirmed toxicity of metal nanoparticles due to long-term accumulation in nontarget tissues, they play a role in the damaged PN regeneration based on the topography modification of scaffolds/conduits, enhancing neurotrophic factor secretion, the ion flow improvement, and the regulation of electrical signals. Determining the fate of neural progenitor cells would be a major achievement in PN regeneration, which seems to be achievable by metal nanoparticles through altering cell vital approaches and controlling their functions. Therefore, in this literature, an attempt was made to provide an overview of the effective activities of metal nanoparticles on the PN regeneration, until the vital clues of the PN regeneration and how they are changed by metal nanoparticles are revealed to the researcher.

Nanomedicine enables autophagy-enhanced cancer-cell ferroptosis

Ferroptosis and autophagy, playing significant roles in tumor treatment, are two typical forms of the programmed cell death. However, the rational combination of ferroptosis and autophagy for synergistic tumor therapy is still highly challenging. Herein, we report on an intriguing nanomedicine strategy for achieving autophagy-enhanced ferroptosis on efficiently combating cancer, which was based on the construction of trehalose-loaded mSiO₂@MnO_x-mPEG (TreMMM) nanoparticles with satisfactory biocompatibility. The nanoparticles are endowed with high glutathione (GSH) consumption efficiency, thereby inducing cancer-cell ferroptosis via inactivating glutathione peroxidases 4 (GPX4). Subsequently, the TreMMM degradation due to the GSH depletion and pH sensitivity contributed to the trehalose release for inducing autophagy, promoting/enhancing ferroptosis by NCOA4-mediated degradation of ferritin. A substantial in vitro and in vivo antitumor effect was achieved by such an intriguing autophagy-enhanced ferroptosis. Therefore, the rational combination of GSH-consumption-induced ferroptosis and trehalose-induced autophagy by nanomedicine design provides an alternative but effective strategy for tumor treatment.

Manganese-doped gold core mesoporous silica particles as a nanoplatform for dual-modality imaging and chemo-chemodynamic combination osteosarcoma therapy

In this study, an effective and facile strategy is reported to construct a multifunctional nanoplatform by in situ doping metal manganese on gold core mesoporous silica nanoparticles (Au@MMSN). After further modification of alendronate (Ald) on Au@MMSN, the obtained Au@MMSN-Ald efficiently integrates bone targeted chemo-chemodynamic combination therapy and dual-modality computed tomography/magnetic resonance (CT/MR) imaging into a single platform. In particular, Au@MMSN-Ald exhibits excellent tumor microenvironment responsive drug release efficiency. The doxorubicin hydrochloride (DOX) loaded Au@MMSN-Ald (DOX@Au@MMSN-Ald) is demonstrated with excellent targeted ability toward osteosarcoma. Accordingly, in a specific tumor microenvironment, DOX@Au@MMSN-Ald also displays outstanding combined efficiency for killing cancer cells in vitro and suppressing the osteosarcoma growth in vivo. Benefiting from the Au nanoparticles confined in the core and manganese ions released from the shell, CT and MR dual-modality imaging were performed to verify the effective accumulation of Au@MMSN-Ald at the tumor site. Overall, the constructed DOX@Au@MMSN-Ald nanoparticles integrated imaging guide, responsive drug release and combination therapy, which may provide some insight for further biomedical applications in efficient osteosarcoma therapy.

Nanomaterial integration into the scaffolding materials for nerve tissue engineering: a review

The nervous system, which consists of a complex network of millions of neurons, is one of the most highly intricate systems in the body. This complex network is responsible for the physiological and cognitive functions of the human body. Following injuries or degenerative diseases, damage to the nervous system is overwhelming because of its complexity and its limited regeneration capacity. However, neural tissue engineering currently has some capacities for repairing nerve deficits and promoting neural regeneration, with more developments in the future. Nevertheless, controlling the guidance of stem cell proliferation and differentiation is a challenging step towards this goal. Nanomaterials have the potential for the guidance of the stem cells towards the neural lineage which can overcome the pitfalls of the classical methods since they provide a unique microenvironment that facilitates cell-matrix and cell-cell interaction, and they can manipulate the cell signaling mechanisms to control stem cells' fate. In this article, the suitable cell sources and microenvironment cues for neuronal tissue engineering were examined. Afterward, the nanomaterials that impact stem cell proliferation and differentiation towards neuronal lineage were reviewed.

Inorganic Biomaterials for Regenerative Medicine

Regenerative medicine leverages the innate potential of the human body to efficiently repair and regenerate damaged tissues using engineered biomaterials. By designing responsive biomaterials with the appropriate biophysical and biochemical characteristics, cellular response can be modulated to direct tissue healing. Recently, inorganic biomaterials have been shown to regulate cellular responses including cell-cell and cell-matrix interactions. Moreover, ions released from these mineral-based biomaterials play a vital role in defining cell identity, as well as driving tissue-specific functions. The intrinsic properties of inorganic biomaterials, such as the release of bioactive ions (e.g., Ca, Mg, Sr, Si, B, Fe, Cu, Zn, Cr, Co, Mo, Mn, Au, Ag, V, Eu, and La), can be leveraged to induce phenotypic changes in cells or modulate the immune microenvironment to direct tissue healing and regeneration. Biophysical characteristics of biomaterials, such as topography, charge, size, electrostatic interactions, and stiffness can be modulated by addition of inorganic micro- and nanoparticles to polymeric networks have also been shown to play an important role in their biological response. In this Review, we discuss the recent emergence of inorganic biomaterials to harness the innate regenerative potential of the body. Specifically, we will discuss various biophysical or biochemical effects of inorganic-based materials in directing cellular response for regenerative medicine applications.

Bio-application of Inorganic Nanomaterials in Tissue Engineering

Inorganic nanomaterials or nanoparticles (INPs) have drawn high attention for their usage in the biomedical field. In addition to the facile synthetic and modifiable property of INPs, INPs have various unique properties that originate from the components of the INPs, such as metal ions that are essential for the human body. Apart from their roles as components of the human body, inorganic materials have unique properties, such as magnetic, antibacterial, and piezoelectric, so that INPs have been widely used as either carriers or inducers. However, most of the bio-applicable INPs, especially those consisting of metal, can cause cytotoxicity. Therefore, INPs require modification to alleviate the harmful effect toward the cells by controlling the release of metal ions from INPs. Even though many attempts have been made to modify INPs, many things, including the side effects of INPs, still remain as obstacles in the bio-application, which need to be elucidated. In this chapter, we introduce novel INPs in terms of their synthetic method and bio-application in tissue engineering.

Multifunctional Mesoporous Silica Nanoprobes: Material Chemistry–Based Fabrication and Bio‐Imaging Functionality

Nanoparticles‐based bioimaging probes are attracting broad attention for various biomedical applications. As one of the mostly explored nanoplatforms, mesoporous silica nanoparticles (MSNs) show high clinical‐translation potential for diagnostic probing/imaging. Based on their tunable morphology, abundant surface chemistry, and well‐defined mesostructure, MSNs are regarded as the desirable platforms for constructing diverse nanoprobes via incorporation of a variety of functional moieties or components. In this review, the authors summarize and discuss recent progress in the rational design and fabrication of multifunctional mesoporous silica‐based composite nanoprobes for versatile bioimaging applications. Four kinds of methodologies for the fabrication of these mesoporous silica‐based nanoprobes are discussed, including encapsulating functional nanoparticles within a mesoporous silica shell, assembling functional nanoparticles on the surface of MSNs, dispersing nanoparticles into the nanometer‐scale mesopores of MSNs, and doping functional moieties into the framework of MSNs. The applications of mesoporous silica nanoprobes in magnetic resonance imaging, ultrasound imaging, computed tomography imaging, fluorescence imaging, positron emission computed tomography, photoacoustic (PA) imaging, and even multimodality imaging are discussed in detail. The biosafety of MSN‐based composite nanoplatforms as bioimaging nanoprobes is also highlighted, accompanied by a deep discussion on facing the challenges and future developments for guaranteeing their further potential clinical translation.

Magnesium-Engineered Silica Framework for pH-Accelerated Biodegradation and DNAzyme-Triggered Chemotherapy

Inorganic nanocarriers have shown their high performance in disease theranostics in preclinical animal models and further great prospects for clinical translation. However, their dissatisfactory biodegradability and pre-drug leakage with nonspecificity to lesion sites significantly hinders the possible clinical translation. To solve these two critical issues, a framework-engineering strategy is introduced to simultaneously achieve enhanced biodegradability and controllable drug releasing, based on the mostly explored mesoporous silica-based nanosystems. The framework of mesoporous silica is engineered by direct Mg doping via a generic dissolution and regrowth approach, and it can transform into the easy biodegradation of magnesium silicate nanocarriers with simultaneous on-demand drug release. Such magnesium silicate nanocarriers can respond to the mild acidic environment of tumor tissue, causing the fast breaking up and biodegradation of the silica framework. More interesting, the released Mg²⁺ can further activate Mg²⁺ -dependent DNAzyme on the surface of hollow mesoporous magnesium silicate nanoparticles (HMMSNs) to cleave the RNA-based gatekeeper, which further accelerates the release of loaded anticancer drugs. Therefore, enhanced anticancer efficiency of chemotherapeutic drugs assisted by the biodegradable intelligent HMMSNs is achieved. The high biocompatibility of nanocarriers and biodegradation products is demonstrated and can be easily excreted via feces and urine guaranteeing their further clinical translation.

Impact of nanoparticles on neuron biology: current research trends

Nanoparticles have enormous applications in textiles, cosmetics, electronics, and pharmaceuticals. But due to their exceptional physical and chemical properties, particularly antimicrobial, anticancer, antibacterial, anti-inflammatory properties, nanoparticles have many potential applications in diagnosis as well as in the treatment of various diseases. Over the past few years, nanoparticles have been extensively used to investigate their response on the neuronal cells. These nanoparticles cause stem cells to differentiate into neuronal cells and promote neuronal cell survivability and neuronal cell growth and expansion. The nanoparticles have been tested both in in vitro and in vivo models. The nanoparticles with various shapes, sizes, and chemical compositions mostly produced stimulatory effects on neuronal cells, but there are few that can cause inhibitory effects on the neuronal cells. In this review, we discuss stimulatory and inhibitory effects of various nanoparticles on the neuronal cells. The aim of this review was to summarize different effects of nanoparticles on the neuronal cells and try to understand the differential response of various nanoparticles. This review provides a bird's eye view approach on the effects of various nanoparticles on neuronal differentiation, neuronal survivability, neuronal growth, neuronal cell adhesion, and functional and behavioral recovery. Finally, this review helps the researchers to understand the different roles of nanoparticles (stimulatory and inhibitory) in neuronal cells to develop effective therapeutic and diagnostic strategies for neurodegenerative diseases.

Bioresponsive and near infrared photon co-enhanced cancer theranostic based on upconversion nanocapsules

Developing nanotheranostics responsive to tumor microenvironments has attracted tremendous attention for on-demand cancer diagnosis and treatment. Herein, a facile Mn-doping strategy was adopted to transform mesoporous silica coated upconversion nanoparticles (UCNPs) to yolk-like upconversion nanostructures which possess a tumor-responsive biodegradation nature. The huge internal space of the innovated nanocarriers is suitable for doxorubicin (DOX) storage, besides, the Mn-doped shell is sensitive to the intratumoral acidity and reducibility, which enables shell biodegradation and further accelerates the breakage of Si-O-Si bonds within the silica framework. This tumor-responsive shell degradation is beneficial for realizing tumor-specific DOX release. Subsequently, polyoxometalate (POM) nanoclusters that can enhance photothermal conversion in response to the tumor reducibility and acidity were modified on the surface of the silica shell, thereby achieving NIR-enhanced shell degradation and also preventing premature DOX leakage. The as-produced thermal effect of the POM couples with the chemotherapy effect of the released DOX to perform a synergetic chemo-photothermal therapy. Additionally, the shell degradation brings size shrinkage to the nanocarriers, allowing faster nanoparticle diffusion and deeper tumor penetration, which is significant for improving theranostic outcomes. Also, the drastic decline of the red/green (R/G) ratio caused by the DOX release can be used to monitor the DOX release content through a fluorescence resonance energy transfer (FRET) method. The MRI effect caused by Mn release together with the MRI/CT/UCL imaging derived from Gd3+/Yb3+/Nd3+/Er3+ co-doped UCNPs under 808 nm laser excitation endow the nanosystem with multiple imaging capability, thus realizing imaging-guided cancer therapy.

Gold Nanoparticles for Modulating Neuronal Behavior

Understanding the detailed functioning and pathophysiology of the brain and the nervous system continues to challenge the scientific community, particularly in terms of scaling up techniques for monitoring and interfacing with complex 3D networks. Nanotechnology has the potential to support this scaling up, where the eventual goal would be to address individual nerve cells within functional units of both the central and peripheral nervous system. Gold nanoparticles provide a variety of physical and chemical properties that have attracted attention as a light-activated nanoscale neuronal interface. This review provides a critical overview of the photothermal and photomechanical properties of chemically functionalized gold nanoparticles that have been exploited to trigger a range of biological responses in neuronal tissues, including modulation of electrical activity and nerve regeneration. The prospects and challenges for further development are also discussed.

"Manganese Extraction" Strategy Enables Tumor-Sensitive Biodegradability and Theranostics of Nanoparticles

Biodegradability of inorganic nanoparticles is one of the most critical issues in their further clinical translations. In this work, a novel "metal ion-doping" approach has been developed to endow inorganic mesoporous silica-based nanoparticles with tumor-sensitive biodegradation and theranostic functions, simply by topological transformation of mesoporous silica to metal-doped composite nanoformulations. "Manganese extraction" sensitive to tumor microenvironment was enabled in manganese-doped hollow mesoporous silica nanoparticles (designated as Mn-HMSNs) to fast promote the disintegration and biodegradation of Mn-HMSNs, further accelerating the breakage of Si-O-Si bonds within the framework. The fast biodegradation of Mn-HMSNs sensitive to mild acidic and reducing microenvironment of tumor resulted in much accelerated anticancer drug releasing and enhanced T1-weighted magnetic resonance imaging of tumor. A high tumor-inhibition effect was simultaneously achieved by anticancer drug delivery mediated by PEGylated Mn-HMSNs, and the high biocompatibility of composite nanosystems was systematically demonstrated in vivo. This is the first demonstration of biodegradable inorganic mesoporous nanosystems with specific biodegradation behavior sensitive to tumor microenvironment, which also provides a feasible approach to realize the on-demand biodegradation of inorganic nanomaterials simply by "metal ion-doping" strategy, paving the way to solve the critical low-biodegradation issue of inorganic drug carriers.

Redoxable heteronanocrystals functioning magnetic relaxation switch for activatable T1 and T2 dual-mode magnetic resonance imaging

T1/T2 dual-mode magnetic resonance (MR) contrast agents (DMCAs) have gained much attention because of their ability to improve accuracy by providing two pieces of complementary information with one instrument. However, most of these agents are "always ON" systems that emit MR contrast regardless of their interaction with target cells or biomarkers, which may result in poor target-to-background ratios. Herein, we introduce a rationally designed magnetic relaxation switch (MGRS) for an activatable T1/T2 dual MR imaging system. Redox-responsive heteronanocrystals, consisting of a superparamagnetic Fe3O4 core and a paramagnetic Mn3O4 shell, are synthesized through seed-mediated growth and subsequently surface-modified with polysorbate 80. The Mn3O4 shell acts as both a protector of Fe3O4 in aqueous environments to attenuate T2 relaxation and as a redoxable switch that can be activated in intracellular reducing environments by glutathione. This simultaneously generates large amounts of magnetically decoupled Mn(2+) ions and allows Fe3O4 to interact with the water protons. This smart nanoplatform shows an appropriate hydrodynamic size for the EPR effect (10-100 nm) and demonstrates biocompatibility. Efficient transitions of OFF/ON dual contrast effects are observed by in vitro imaging and MR relaxivity measurements. The ability to use these materials as DMCAs is demonstrated via effective passive tumor targeting for T1- and T2-weighted MR imaging in tumor-bearing mice.

Controlled actuation of therapeutic nanoparticles: an update on recent progress

A primary envisioned use for nanoparticles (NPs) in a cellular context is for controlled drug delivery where the full benefit of NP attributes (small size, large drug cargo loading capacity) can improve the pharmacokinetics of the drug cargo. This requires the ability to controllably manipulate the release of the drug cargo from the NP vehicle or ‘controlled actuation’. In this review, we highlight new developments in this field from 2013 to 2015. The number and breadth of reports are a testament to the significant advancements made in this field over this time period. We conclude with a perspective of how we envision this field to continue to develop in the years to come.