Nano-bio interactions: the implication of size-dependent biological effects of nanomaterials

Cholesterol-Modified DNA Nanostructures Serve as Effective Non-Viral Carriers for Delivering siRNA to the Kidneys to Prevent Acute Kidney Injury

With the emergence of gene therapy utilizing viral vectors, the potential risks associated with these vectors have prompted increased attention toward non-viral alternatives. DNA nanotechnology enables the assembly of specific oligonucleotide chains into nanostructures possessing defined spatial configurations. Due to their inherent characteristics, DNA nanostructures possess natural advantages as carriers for regulating gene expression in a non-viral manner. Cholesterol modification can convert DNA nanostructures from hydrophilic materials to amphiphilic materials, thereby extending their systemic circulation time. In this study, the high-dimensional design and cholesterol modification are shown to prolong the systemic circulation half-life of DNA nanostructures in mice. Specifically, the tetrahedron structure modified with three cholesterol molecules (TDN-3Chol) exhibit excellent circulation time and demonstrate a preference for renal uptake. The unique characteristics of TDN-3Chol can effectively deliver p53 siRNA to the mouse renal tubular tissue, resulting in successful knockdown of p53 and demonstrating its potential for preventing acute kidney injury. Furthermore, TDN-3Chol is not exhibited significant toxicity in mice, highlighting its promising role as a non-viral vector for targeted gene expression regulation in the kidneys. The designed non-viral vector as a prophylactic medication shows potential in addressing the current clinical challenges associated with nephrotoxic drugs.

AMP-Coated TiO2 Doped ZnO Nanomaterials Enhanced Antimicrobial Activity and Efficacy in Otitis Media Treatment by Elevating Hydroxyl Radical Levels

Background

In the past decades, antimicrobial resistance (AMR) has been a major threat to global public health. Long-term, chronic otitis media is becoming more challenging to treat, thus the novel antibiotic alternative agents are much needed.

Methods

ZnO@TiO2@AMP (ATZ NPs) were synthesized through a solvothermal method and subjected to comprehensive characterization. The in vitro and in vivo antibacterial effect and biocompatibility of ATZ NPs were evaluated. For the antibacterial mechanism exploration, we utilized the Electron Paramagnetic Resonance (EPR) Spectrometer to detect and analyze the hydroxyl radicals produced by ATZ NPs.

Results

ATZ NPs exhibited a spherical structure of 99.85 nm, the drug-loading rate for ZnO was 20.73%, and AMP within ATZ NPs was 41.86%. Notably, the Minimum Inhibitory Concentration (MIC) value of ATZ NPs against Staphylococcus aureus (S. aureus), methicillin-resistant Staphylococcus aureus (MRSA), and Streptococcus pneumoniae (S. pneumoniae) were 10 μg/mL, and Minimum Bactericidal Concentration (MBC) value of ATZ NPs against S. aureus, and S. pneumoniae were 50 μg/mL. In comparison to the model group, the treatment of otitis media with ATZ NPs significantly reduces inflammatory exudation in the middle ear cavity, with no observable damage to the tympanic membrane. Both in vivo and in vitro toxicity tests indicating the good biocompatibility of ATZ NPs. Moreover, EPR spectroscopy results highlighted the superior ability of ATZ NPs to generate hydroxyl radicals (·OH) compared to ZnO NPs.

Conclusion

ATZ NPs exhibited remarkable antibacterial properties both in vivo and in vitro. This innovative application of advanced ATZ NPs, bringing great promise for the treatment of otitis media.

Biodegradable Monometallic Aluminum as a Biotuner for Tumor Pyroptosis

Pyroptosis is an effective anti-tumor strategy. However, monometallic pyroptosis biotuners have not been explored until now. Here, we discover for the first time that biodegradable monometallic Al can act as a pyroptosis biotuner for tumor therapy. pH-sensitive Al nanoparticles (Al@P) are obtained by equipping polyethylene glycol-b-(poly(methyl methacrylate)-co-poly(4-vinylpyridine), which can exert their effect at the tumor site without affecting normal cells. The H2 and Al3+ release by Al@P in the acidic environment of tumors disrupts the redox balance and ionic homeostasis in tumor cells, thus generating large amounts of reactive oxygen species (ROS), leading to caspase-1 activation, gasdermin D cleavage, and IL-1β/LDH release, which induces canonical pyroptotic death. Meanwhile, the prodrug Doxorubicin (Pro-DOX) is successfully loaded onto Al@P (Al@P-P) and can be activated by ROS to release DOX in the tumor cells, thus further improving the tumor-killing efficiency. Ultimately, Al@P-P is degradable and exhibits efficient tumor inhibition.

Influence of silver doping on pro-inflammatory and pro-fibrogenic effects of nano-titanium dioxide in murine lung

Silver is usually loaded on nano-titanium dioxide (TiO2 ) through photodeposition method to enhance visible-light catalytic functions for environment purification. However, little is known about how the toxicity changes after silver doping and how the physicochemical properties of loaded components affect nanocomposite toxicity. In this study, Ag-TiO2 with different sizes and contents of silver particles were obtained by controlling photodeposition time (PDT) and silver addition amount. Pro-inflammatory and pro-fibrogenic responses of these photocatalysts were evaluated in male C57BL/6J murine lung. As a result, silver was well assembled on TiO2 , promoting visible-light catalytic activity. Notably, the size of silver particles increased with PDT. Meanwhile, toxicity results showed that pure TiO2 (P25) mainly caused neutrophil infiltration, while 2 wt/wt% silver-loaded TiO2 recruited more types of inflammatory cells in the lung. Both of them caused the increase of proinflammatory cytokines while decreasing the anti-inflammatory cytokine in bronchoalveolar lavage fluid. However, 2 wt/wt% silver doping also accelerated the lung pro-fibrogenic response of photocatalysts in the subacute phase from evidence of collagen deposition and hydroxyproline concentrations. Mechanistically, the overactivation of TGFBR2 receptors in TGF-β/smads pathways by silver-loaded TiO2 rather than pure TiO2 may be the reason why silver-loaded TiO2 can promote pro-fibrogenic effect response. Intriguingly, the increased toxicity caused by silver doping can be rescued by increasing the size of the loaded silver or decreasing the silver amount. These results may be important for the new understanding of the toxicity of TiO2 -based photocatalysts.

Nano-bio interactions in mRNA nanomedicine: Challenges and opportunities for targeted mRNA delivery

Upon entering the biological milieu, nanomedicines swiftly interact with the surrounding tissue fluid, subsequently being enveloped by a dynamic interplay of biomacromolecules, such as carbohydrates, nucleic acids, and cellular metabolites, but with predominant serum proteins within the biological corona. A notable consequence of the protein corona phenomenon is the unintentional loss of targeting ligands initially designed to direct nanomedicines toward particular cells or organs within the in vivo environment. mRNA nanomedicine displays high demand for specific cell and tissue-targeted delivery to effectively transport mRNA molecules into target cells, where they can exert their therapeutic effects with utmost efficacy. In this review, focusing on the delivery systems and tissue-specific applications, we aim to update the nanomedicine population with the prevailing and still enigmatic paradigm of nano-bio interactions, a formidable hurdle in the pursuit of targeted mRNA delivery. We also elucidate the current impediments faced in mRNA therapeutics and, by contemplating prospective avenues-either to modulate the corona or to adopt an 'ally from adversary' approach-aim to chart a course for advancing mRNA nanomedicine.

Ag/TiO2 nanohybrids induce fibrosis-related epithelial-mesenchymal transition in lung epithelial cells and the influences of silver content and silver particle size

The controlled synthesis of silver nanoparticles (AgNPs) decorated TiO2 nanohybrids (Ag/TiO2) for photocatalysis has received considerable attention. These photocatalysts are widely used in environment and energy, resulting in human exposure through inhalation. Pure TiO2 is generally considered a low-toxic nanomaterial. However, little is known about the toxicity after AgNPs loading. In this study, silver-decorated TiO2 nanohybrids were controllably synthesized by the photodeposition method, and their toxic effects on murine lung and human lung epithelial cells were explored. As a result, silver loading significantly enhanced the effect of TiO2 photocatalyst on EMT in lung epithelial cells, potentially acting as a pro-fibrogenic effect in murine lung. Meanwhile, the increase in autophagy vacuoles, LC3-II marker, stub-RFP-sens-GFP-LC3 fluorescence assay, and LC3 turnover assay showed that silver loading also significantly increased autophagy flux. Furthermore, analysis of autophagy inhibition by 3-Methyladenine indicated that the promotion of EMT by silver loading was related to the increased autophagy flux. Intriguingly, the autophagy and EMT biological effects could be alleviated when the silver loading amount was reduced or silver particle size was increased, and the enhanced pro-fibrogenic effect was mitigated at the same time. This study supplemented safety information of Ag-decorated TiO2 nanohybrids and provided methods of controlled synthesis for reducing toxicity.

SciRAPnano: a pragmatic and harmonized approach for quality evaluation of in vitro toxicity data to support risk assessment of nanomaterials

Large amounts of nanotoxicity data from alternative non-animal (in vitro) test methods have been generated, but there is a lack of harmonized quality evaluation approaches for these types of data. Tools for scientifically sound and structured evaluation of the reliability and relevance of in vitro toxicity data to effectively inform regulatory hazard assessment of nanomaterials (NMs), are needed. Here, we present the development of a pragmatic approach to facilitate such evaluation. The tool was developed based on the Science in Risk Assessment and Policy (SciRAP) tool currently applicable to quality evaluation of chemical toxicity studies. The approach taken to develop the tool, referred to as SciRAPnano, included refinement of the original SciRAP in vitro tool through implementation of identified NM-relevant criteria, and further refined based on a set of case studies involving evaluation of 11 studies investigating in vitro toxicity of nano-sized titanium dioxide. Parameters considered cover key physicochemical properties as well as assay-specific aspects that impact NM toxicity, including NM interference with test methods and NM transformation. The final SciRAPnano tool contains 38 criteria for reporting quality, 19 criteria for methodological quality, and 4 guidance items to evaluate relevance. The approach covers essential parameters for pragmatic and harmonized evaluation of NM in vitro toxicity studies and allows for structured use of in vitro data in regulatory hazard assessment of NMs, including transparency on data quality.

Piezoelectric materials for neuroregeneration: a review

The purpose of nerve regeneration via tissue engineering strategies is to create a microenvironment that mimics natural nerve growth for achieving functional recovery. Biomaterial scaffolds offer a promising option for the clinical treatment of large nerve gaps due to the rapid advancement of materials science and regenerative medicine. The design of biomimetic scaffolds should take into account the inherent properties of the nerve and its growth environment, such as stiffness, topography, adhesion, conductivity, and chemical functionality. Various advanced techniques have been employed to develop suitable scaffolds for nerve repair. Since neuronal cells have electrical activity, the transmission of bioelectrical signals is crucial for the functional recovery of nerves. Therefore, an ideal peripheral nerve scaffold should have electrical activity properties similar to those of natural nerves, in addition to a delicate structure. Piezoelectric materials can convert stress changes into electrical signals that can activate different intracellular signaling pathways critical for cell activity and function, which makes them potentially useful for nerve tissue regeneration. However, a comprehensive review of piezoelectric materials for neuroregeneration is still lacking. Thus, this review systematically summarizes the development of piezoelectric materials and their application in the field of nerve regeneration. First, the electrical signals and natural piezoelectricity phenomenon in various organisms are briefly introduced. Second, the most commonly used piezoelectric materials in neural tissue engineering, including biocompatible piezoelectric polymers, inorganic piezoelectric materials, and natural piezoelectric materials, are classified and discussed. Finally, the challenges and future research directions of piezoelectric materials for application in nerve regeneration are proposed.

Peripheral nerves directly mediate the transneuronal translocation of silver nanomaterials from the gut to central nervous system

The blood circulation is considered the only way for the orally administered nanoparticles to enter the central nervous systems (CNS), whereas non-blood route-mediated nanoparticle translocation between organs is poorly understood. Here, we show that peripheral nerve fibers act as direct conduits for silver nanomaterials (Ag NMs) translocation from the gut to the CNS in both mice and rhesus monkeys. After oral gavage, Ag NMs are significantly enriched in the brain and spinal cord of mice with particle state however do not efficiently enter the blood. Using truncal vagotomy and selective posterior rhizotomy, we unravel that the vagus and spinal nerves mediate the transneuronal translocation of Ag NMs from the gut to the brain and spinal cord, respectively. Single-cell mass cytometry analysis revealed that enterocytes and enteric nerve cells take up significant levels of Ag NMs for subsequent transfer to the connected peripheral nerves. Our findings demonstrate nanoparticle transfer along a previously undocumented gut-CNS axis mediated by peripheral nerves.

Propranolol-Loaded Limonene-Based Microemulsion Thermo-Responsive Mucoadhesive Nasal Nanogel: Design, In Vitro Assessment, Ex Vivo Permeation, and Brain Biodistribution

Propranolol is the first-line drug for managing migraine attacks. D-limonene is a citrus oil known for its neuroprotective mechanism. Thus, the current work aims to design a thermo-responsive intranasal limonene-based microemulsion mucoadhesive nanogel to improve propranolol efficacy. Microemulsion was fabricated using limonene and Gelucire^® as the oily phase, Labrasol^®, Labrafil^®, and deionized water as the aqueous phase, and was characterized regarding its physicochemical features. The microemulsion was loaded in thermo-responsive nanogel and evaluated regarding its physical and chemical properties, in vitro release, and ex vivo permeability through sheep nasal tissues. Its safety profile was assessed via histopathological examination, and its capability to deliver propranolol effectively to rats' brains was examined using brain biodistribution analysis. Limonene-based microemulsion was of 133.7 ± 0.513 nm diametric size with unimodal size distribution and spheroidal shape. The nanogel showed ideal characteristics with good mucoadhesive properties and in vitro controlled release with 1.43-fold enhancement in ex vivo nasal permeability compared with the control gel. Furthermore, it displayed a safe profile as elucidated by the nasal histopathological features. The nanogel was able to improve propranolol brain availability with C_max 970.3 ± 43.94 ng/g significantly higher than the control group (277.7 ± 29.71 ng/g) and with 382.4 % relative central availability, which confirms its potential for migraine management.

A Nano-QSTR model to predict nano-cytotoxicity: an approach using human lung cells data

BACKGROUND

The widespread use of new engineered nanomaterials (ENMs) in industries such as cosmetics, electronics, and diagnostic nanodevices, has been revolutionizing our society. However, emerging studies suggest that ENMs present potentially toxic effects on the human lung. In this regard, we developed a machine learning (ML) nano-quantitative-structure-toxicity relationship (QSTR) model to predict the potential human lung nano-cytotoxicity induced by exposure to ENMs based on metal oxide nanoparticles.

RESULTS

Tree-based learning algorithms (e.g., decision tree (DT), random forest (RF), and extra-trees (ET)) were able to predict ENMs' cytotoxic risk in an efficient, robust, and interpretable way. The best-ranked ET nano-QSTR model showed excellent statistical performance with R² and Q²-based metrics of 0.95, 0.80, and 0.79 for training, internal validation, and external validation subsets, respectively. Several nano-descriptors linked to the core-type and surface coating reactivity properties were identified as the most relevant characteristics to predict human lung nano-cytotoxicity.

CONCLUSIONS

The proposed model suggests that a decrease in the ENMs diameter could significantly increase their potential ability to access lung subcellular compartments (e.g., mitochondria and nuclei), promoting strong nano-cytotoxicity and epithelial barrier dysfunction. Additionally, the presence of polyethylene glycol (PEG) as a surface coating could prevent the potential release of cytotoxic metal ions, promoting lung cytoprotection. Overall, the current work could pave the way for efficient decision-making, prediction, and mitigation of the potential occupational and environmental ENMs risks.

Promotion effects and mechanisms of molybdenum disulfide on the propagation of antibiotic resistance genes in soil

The rapid development of nanotechnology has aroused considerable attentions toward understanding the effects of engineered nanomaterials (ENMs) on the propagation of antibiotic resistance. Molybdenum disulfide (MoS₂) is an extensively used ENM and poses potential risks associated with environmental exposure; nevertheless, the role of MoS₂ toward antibiotic resistance genes (ARGs) transfer remains largely unknown. Herein, it was discovered that MoS₂ nanosheets accelerated the horizontal transfer of RP4 plasmid across Escherichia coli in a dose-dependent manner (0.5-10 mg/L), with the maximum transfer frequency 2.07-fold higher than that of the control. Integration of physiological, transcriptomics, and metabolomics analyses demonstrated that SOS response in bacteria was activated by MoS₂ due to the elevation of oxidative damage, accompanied by cell membrane permeabilization. MoS₂ promoted bacterial adhesion and intercellular contact via stimulating the secretion of extracellular polysaccharides. The ATP levels were maximally increased by 305.7 % upon exposure to MoS₂, and the expression of plasmid transfer genes was up-regulated, contributing to the accelerated plasmid conjugation and increased ARG abundance in soil. Our findings highlight the roles of emerging ENMs (e.g., MoS₂) in ARGs dissemination, which is significant for the safe applications and risk management of ENMs under the development scenarios of nanotechnology.

Emerging ultrasmall luminescent nanoprobes for in vivo bioimaging

Photoluminescence (PL) imaging has become a fundamental tool in disease diagnosis, therapeutic evaluation, and surgical navigation applications. However, it remains a big challenge to engineer nanoprobes for high-efficiency in vivo imaging and clinical translation. Recent years have witnessed increasing research efforts devoted into engineering sub-10 nm ultrasmall nanoprobes for in vivo PL imaging, which offer the advantages of efficient body clearance, desired clinical translation potential, and high imaging signal-to-noise ratio. In this review, we present a comprehensive summary and contrastive discussion of emerging ultrasmall luminescent nanoprobes towards in vivo PL bioimaging of diseases. We first summarize size-dependent nano-bio interactions and imaging features, illustrating the unique attributes and advantages/disadvantages of ultrasmall nanoprobes differentiating them from molecular and large-sized probes. We also discuss general design methodologies and PL properties of emerging ultrasmall luminescent nanoprobes, which are established based on quantum dots, metal nanoclusters, lanthanide-doped nanoparticles, and silicon nanoparticles. Then, recent advances of ultrasmall luminescent nanoprobes are highlighted by surveying their latest in vivo PL imaging applications. Finally, we discuss existing challenges in this exciting field and propose some strategies to improve in vivo PL bioimaging and further propel their clinical applications.

Oral administration of silver nanomaterials affects the gut microbiota and metabolic profile altering the secretion of 5-HT in mice

Due to their excellent antibacterial ability, silver nanomaterials (Ag NMs) are the most frequently used nanomaterials. Their widespread use introduces the risk of human ingestion. However, the potential toxicity of Ag NMs to the gut microbiota and their metabolic profile are yet to be fully explored. In this study, we examined the effects of Ag NMs after oral administration (0.5 mg kg^-1 and 2.5 mg kg^-1, 14 and 28 days) on gut homeostasis by integrating tissue imaging, 16s rRNA gene sequencing and metabolomics techniques. We uncovered that silver nanoparticles (Ag NPs) and silver nanowires (Ag NWs) altered the structure (inhibiting the proliferation of Gram-negative bacteria) and decreased the diversity of gut microbiota in mice after short-term (14 days) exposure, while the microbial community tended to recover after long-term exposure (28 days), indicating that the resistance and resilience of the gut microbiome may pose a defense against the interference by reactive, exogenous nanomaterials. Interestingly, even though the gut microbiota structure recovered after 28 days of exposure, the gut metabolites significantly changed, showing increased 1H-indole-3-carboxylic acid and elevated levels of 5-HT in the gut and blood. Collectively, our results provide a piece of evidence on the association between the ingestion of exogenous nanoparticles and gut homeostasis, especially the metabolic profile of the host. This work thus provides additional insights for the continued investigation of the adverse effects of silver nanomaterials on biological hosts.

Inherent Capability of Self-Assembling Nanostructures in Specific Proteasome Activation for Cancer Cell Pyroptosis

Understanding the direct interaction of nanostructures per se with biological systems is important for biomedical applications. However, whether nanostructures regulate biological systems by targeting specific cellular proteins remains largely unknown. In the present work, self-assembling nanomicelles are constructed using small-molecule oleanolic acid (OA) as a molecular template. Unexpectedly, without modifications by functional ligands, OA nanomicelles significantly activate cellular proteasome function by directly binding to 20S proteasome subunit alpha 6 (PSMA6). Mechanism study reveals that OA nanomicelles interact with PSMA6 to dynamically modulate its N-terminal domain conformation change, thereby controlling the entry of proteins into 20S proteasome. Subsequently, OA nanomicelles accelerate the degradation of several crucial proteins, thus potently driving cancer cell pyroptosis. For translational medicine, OA nanomicelles exhibit a significant anticancer potential in tumor-bearing mouse models and stimulate immune cell infiltration. Collectively, this proof-of-concept study advances the mechanical understanding of nanostructure-guided biological effects via their inherent capacity to activate proteasome.

Nanomaterials-Based Novel Immune Strategies in Clinical Translation for Cancer Therapy

Immunotherapy shows a lot of promise for addressing the problems with traditional cancer treatments. Researchers and clinicians are working to create innovative immunological techniques for cancer detection and treatment that are more selective and have lower toxicity. An emerging field in cancer therapy, immunomodulation offers patients an alternate approach to treating cancer. These therapies use the host's natural defensive systems to identify and remove malignant cells in a targeted manner. Cancer treatment is now undergoing somewhat of a revolution due to recent developments in nanotechnology. Diverse nanomaterials (NMs) have been employed to overcome the limits of conventional anti-cancer treatments such as cytotoxic, surgery, radiation, and chemotherapy. Aside from that, NMs could interact with live cells and influence immune responses. In contrast, unexpected adverse effects such as necrosis, hypersensitivity, and inflammation might result from the immune system (IS)'s interaction with NMs. Therefore, to ensure the efficacy of immunomodulatory nanomaterials, it is essential to have a comprehensive understanding of the intricate interplay that exists between the IS and NMs. This review intends to present an overview of the current achievements, challenges, and improvements in using immunomodulatory nanomaterials (iNMs) for cancer therapy, with an emphasis on elucidating the mechanisms involved in the interaction between NMs and the immune system of the host.

Opportunities and Challenges for Alternative Nanoplasmonic Metals: Magnesium and Beyond

Materials that sustain localized surface plasmon resonances have a broad technology potential as attractive platforms for surface-enhanced spectroscopies, chemical and biological sensing, light-driven catalysis, hyperthermal cancer therapy, waveguides, and so on. Most plasmonic nanoparticles studied to date are composed of either Ag or Au, for which a vast array of synthetic approaches are available, leading to controllable size and shape. However, recently, alternative materials capable of generating plasmonically enhanced light-matter interactions have gained prominence, notably Cu, Al, In, and Mg. In this Perspective, we give an overview of the attributes of plasmonic nanostructures that lead to their potential use and how their performance is dictated by the choice of plasmonic material, emphasizing the similarities and differences between traditional and emerging plasmonic compositions. First, we discuss the materials limitation encapsulated by the dielectric function. Then, we evaluate how size and shape maneuver localized surface plasmon resonance (LSPR) energy and field distribution and address how this impacts applications. Next, biocompatibility, reactivity, and cost, all key differences underlying the potential of non-noble metals, are highlighted. We find that metals beyond Ag and Au are of competitive plasmonic quality. We argue that by thinking outside of the box, i.e., by looking at nonconventional materials such as Mg, one can broaden the frequency range and, more importantly, combine the plasmonic response with other properties essential for the implementation of plasmonic technologies.

Nano-bio interactions: A major principle in the dynamic biological processes of nano-assemblies

Controllable nano-assembly with stimuli-responsive groups is emerging as a powerful strategy to generate theranostic nanosystems that meet unique requirements in modern medicine. However, this prospective field is still in a proof-of-concept stage due to the gaps in our understanding of complex-(nano-assemblies)-complex-(biosystems) interactions. Indeed, stimuli-responsive assembly-disassembly is, in and of itself, a process of nano-bio interactions, the key steps for biological fate and functional activity of nano-assemblies. To provide a comprehensive understanding of these interactions in this review, we first propose a 4W1H principle (Where, When, What, Which and How) to delineate the relevant dynamic biological processes, behaviour and fate of nano-assemblies. We further summarize several key parameters that govern effective nano-bio interactions. The effects of these kinetic parameters on ADMET processes (absorption, distribution, metabolism, excretion and transformation) are then discussed. Furthermore, we provide an overview of the challenges facing the evaluation of nano-bio interactions of assembled nanodrugs. We finally conclude with future perspectives on safe-by-design and application-driven-design of nano-assemblies. This review will highlight the dynamic biological and physicochemical parameters of nano-bio interactions and bridge discrete concepts to build a full spectrum understanding of the biological outcomes of nano-assemblies. These principles are expected to pave the way for future development and clinical translation of precise, safe and effective nanomedicines with intelligent theranostic features.

How Nanotechniques Could Vitalize the O-GlcNAcylation-Targeting Approach for Cancer Therapy

Accumulated data indicated that many types of cancers have increased protein O-GlcNAcylation at cell surface and inside cells. The aberrant O-GlcNAcylation is considered a potential therapeutic target. Although several types of compounds capable of inhibiting O-GlcNAcylation have been developed, their low solubility, poor permeability and delivery efficiency have impeded the application for in vivo and pre-clinical studies. Nanocarriers have the advantages of controllable drug release and active cancer-targeting capability. Moreover, nanoparticles can improve drug delivery efficiency and reduce the non-specific distribution in normal tissues by the enhanced permeability and retention (EPR) effect in cancer. Taking the advantage of O-GlcNAc-specific antibodies or lectins, nanoparticles could further improve their cancer-targeting capability. Although nanocarriers targeting the canonical N- and O-linked glycosylation have been extensively investigated for cancer detection and therapy, application of nanotechniques for the specific targeting of O-GlcNAcylation has not been actively pursued. This review summarizes the general features of GlcNAcylation and its alterations in cancers. Analyses are focused on the following areas: How the nanocarriers may improve the solubility and/or cell permeability of O-GlcNAc transferase (OGT) inhibitors; The modification of nanocarriers with lectins or antibodies for active targeting of O-GlcNAc; The nanocarriers-mediated co-delivery of OGT inhibitors and conventional drugs, which may lead to synergistic effects. Unsolved issues impeding the research progression on O-GlcNAcylation-targeting scheme are also discussed.

Bacteria-propelled microtubular motors for efficient penetration and targeting delivery of thrombolytic agents

Effective thrombolysis is critical to rapidly rebuild blood flow for thrombosis patients. Drug delivery systems have been developed to address inadequate pharmacokinetics of thrombolytic agents, but challenges still remain in the timely removal of blood clots regarding the dense fibrin networks. Herein, rod-shaped tubular micromotors were developed to achieve efficient penetration and thorough destruction of thrombi. By using electrospun fiber fragments as the template, urokinase (uPA)-loaded polydopamine (PDA) microtubes with surface decorated fucoidan (^FuPDA_uPA) were prepared at the aspect ratio of around 2. One E. coli Nissle 1917 (EcN) was assembled into one microtube to construct a ^FuPDA_uPA@EcN hybrid micromotor through PDA adhesion and L-aspartate induction. The pharmacokinetic analysis indicates that the encapsulation of uPA into micromotors extends the half-life from 0.4 to 5.6 h and increases the bioavailability over 10 times. EcN-propelled motion elevates adsorption capacities of ^FuPDA_uPA@EcN for more than four times compared with that of ^FuPDA_uPA. The fucoidan-mediated targeting causes 2-fold higher thrombolysis capacity in vitro and over 10-fold higher uPA accumulation in thrombi in vivo. In the treatment of venous thrombi at mouse hindlimbs, intravenous administration of ^FuPDA_uPA@EcN completely removed blood clots with almost full recovery of blood flows and apparently alleviated tail bleeding. It should be noted that ^FuPDA_uPA@EcN treatment at a reduced uPA dose caused no significant difference in the blood flow rate compared with those of ^FuPDA_uPA. The synergistic action of fucoidan-induced targeting and EcN-driven motion provides a prerequisite for promoting thrombolytic efficacy and reducing uPA dose and bleeding side effect. STATEMENT OF SIGNIFICANCE: The standard treatment to thrombosis patient is intravenous infusion of thrombolytic agents, but the associated bleeding complications and impairment of normal haemostasis greatly offset the therapeutic benefits. Drug delivery systems have been developed to address the limitations of inadequate pharmacokinetics of thrombolytic agents, but challenges still exist in less efficient penetration into dense networks for thorough destruction of thrombi. Up to now only few attempts have been made to construct nano-/micromotors for combating thrombosis and there is no single case that antithrombosis is assisted by bacteria or cells-propelled motors. Herein, bacteria-propelled microtubes were developed to carry urokinase for efficient penetration into blood clots and effective thrombolysis. The synergistic action of bacteria-driven motion and specific ligand-induced targeting holds a promising treatment strategy for life-threatening cardiovascular diseases such as thrombosis and atherosclerosis.

Nanocarriers Call the Last Shot in the Treatment of Brain Cancers

Our brain is protected by physio-biological barriers. The blood–brain barrier (BBB) main mechanism of protection relates to the abundance of tight junctions (TJs) and efflux pumps. Although BBB is crucial for healthy brain protection against toxins, it also leads to failure in a devastating disease like brain cancer. Recently, nanocarriers have been shown to pass through the BBB and improve patients’ survival rates, thus becoming promising treatment strategies. Among nanocarriers, inorganic nanocarriers, solid lipid nanoparticles, liposomes, polymers, micelles, and dendrimers have reached clinical trials after delivering promising results in preclinical investigations. The size of these nanocarriers is between 10 and 1000 nm and is modified by surface attachment of proteins, peptides, antibodies, or surfactants. Multiple research groups have reported transcellular entrance as the main mechanism allowing for these nanocarriers to cross BBB. Transport proteins and transcellular lipophilic pathways exist in BBB for small and lipophilic molecules. Nanocarriers cannot enter via the paracellular route, which is limited to water-soluble agents due to the TJs and their small pore size. There are currently several nanocarriers in clinical trials for the treatment of brain cancer. This article reviews challenges as well as fitting attributes of nanocarriers for brain tumor treatment in preclinical and clinical studies.

Tailoring the physicochemical properties of nanomaterials for immunomodulation

Immunomodulation is poised to revolutionize the treatment of cancer, autoimmune diseases, and many other inflammation-related disorders. The immune system in these conditions can be either activated or suppressed by nanocarriers loaded with bioactive molecules. Although immunomodulation via these therapeutics has long been recognized, and a broad range of nanocarriers have been designed to accommodate varied usages, less studies have focused on the effects of nanomaterial physicochemical properties on immune responses, especially the immunity altered by nanocarrier materials alone. Conclusions are sometimes seemly inconsistent due to the complexities of nanomaterials and the immune system. An in-depth understanding of the nanocarrier-induced immune responses is essential for clinical applications. In this review, we summarize recent studies of the immune responses influenced by nanomaterial physicochemical properties with an emphasis on the intrinsic features of nanomaterials that modulate the innate and adaptive immunities. We then provide our perspectives on the design of nanomaterials for immunomodulation.

Interactions of cationic gold nanoclusters with serum proteins and effects on their cellular responses

Cationic nanoparticles (NPs) have shown great potential in biological applications owing to their distinct features such as favorable cellular internalization and easy binding to biomolecules. However, our current knowledge of cationic NPs' biological behavior, i.e., NP-protein interactions, is still rather limited. Herein, we choose ultrasmall-sized fluorescent gold nanoclusters (AuNCs) coated by (11-mercaptoundecyl) - N, N, N - trimethylammonium bromide (MUTAB) as representative cationic NPs, and systematically study their interactions with different serum proteins at nano-bio interfaces. By monitoring the fluorescence intensity of MUTAB-AuNCs, all proteins are observed to bind with roughly micromolar affinities to AuNCs and quench their fluorescence. Transient fluorescence spectroscopy, X-ray photoelectron spectroscopy and isothermal titration calorimetry are also adopted to characterize the physicochemical properties of MUTAB-AuNCs after the protein adsorption. Concomitantly, circular dichroism spectroscopy reveals that cationic AuNCs can exert protein-dependent conformational changes of these serum proteins. Moreover, protein adsorption onto cationic AuNCs can significantly influence their cellular responses such as cytotoxicity and uptake efficiency. These results provide important knowledge towards understanding the biological behaviors of cationic nanoparticles, which will be helpful in further designing and utilizing them for safe and efficient biomedical applications.

A Nature-Inspired Metal-Organic Framework Discriminator for Differential Diagnosis of Cancer Cell Subtypes

Metabolic glycan labeling (MGL) followed by bioorthogonal chemistry provides a powerful tool for tumor imaging and therapy. However, selectively metabolic labeling of cells or tissues of interest remains a challenge. Particularly, owing to tumor heterogeneity including tumor subtypes and interpatient heterogeneity, it is far more difficult to realize tumor-cell-selective metabolic labeling for precise diagnosis. Inspired by nature, we designed azidosugar-functionalized metal-organic frameworks camouflaged with cancer cell membranes to accomplish cancer-cell-selective MGL in vivo. With abundant receptors, this biomimetic platform not only selectively targets homotypic cells but also realizes different breast cancer subtype-selective MGL. Moreover, the endo/lysosomal-escaped ZIF-8 can make azidosugar escape from lysosomes and accelerate its metabolic incorporation. This strategy also takes advantage of cancer-tissue-derived cell membranes, which may have huge potential for personalized diagnosis and therapy.

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

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

Potential roles of Kruppel-like factors in mediating adverse vascular effects of nanomaterials: A review

The development of nanotechnology leads to the exposure of human beings to nanomaterials (NMs), and there is a health concern about the adverse vascular effects of NMs. Current data from epidemiology, controlled human exposure, and animal studies suggested that exposure to NMs could induce cardiopulmonary effects. In support of in vivo findings, in vitro studies showed that direct contact of vascular cells with NMs could induce endothelial cell (EC) activation and promote macrophage foam cell formation, although only limited studies showed that NMs could damage vascular smooth muscle cells and promote their phenotypic switch. It has been proposed that NMs induced adverse vascular effects via different mechanisms, but it is still necessary to understand the upstream events. Kruppel-like factors (KLFs) are a set of C2H2 zinc finger transcription factors (TFs) that can regulate various aspects of vascular biology, but currently, the roles of KLF2 in mediating the adverse vascular effects of NMs have gained little attention by toxicologists. This review summarized current knowledge about the adverse vascular effects of NMs and proposed the potential roles of KLFs in mediating these effects based on available data from toxicological studies as well as the current understanding about KLFs in vascular biology. Finally, the challenges in investigating the role of KLFs in vascular toxicology were also summarized. Considering the important roles of KLFs in vascular biology, further studies are needed to understand the influence of NMs on KLFs and the downstream events.

Reduction-Responsive Chemo-Capsule-Based Prodrug Nanogel for Synergistic Treatment of Tumor Chemotherapy

Chemotherapy is currently the most universal therapeutics to tumor treatment; however, limited curative effect and undesirable drug resistance effect are the two major clinical bottlenecks. Herein, we develop a two-in-one cross-linking strategy to prepare a stimuli-responsive prodrug nanogel by virtue of delivering a combination of chemotherapeutic drugs of 10-hydroxy camptothecin and doxorubicin for ameliorating the deficiencies of chemotherapy and amplifying the cancer therapeutic efficiency. The obtained prodrug nanogel has both high drug loading capacity and suitable nanoscale size, which are beneficial to the cell uptake and tumor penetration. Moreover, the chemotherapeutic drugs are released from the prodrug nanogel in response to the reductive tumor microenvironment, enhancing tumor growth inhibition in vitro and in vivo by the synergistic DNA damage. Based on these results, the unique prodrug nanogel would be a promising candidate for satisfactory tumor treatment-based chemotherapy by a simple but efficient strategy.

Biodegradable Quantum Composites for Synergistic Photothermal Therapy and Copper-Enhanced Chemotherapy

In recent times, the combination therapy has garnered enormous interest owing to its great potential in clinical research. It has been reported that disulfiram, a clinical antialcoholism drug, could be degraded to diethyldithiocarbamate (DDTC) in vivo and subsequently result in the copper-DDTC complex (Cu(DDTC)₂) toward ablating cancer cells. In addition, the ultrasmall copper sulfide nanodots (CuS NDs) have shown great potential in cancer treatment because of their excellent photothermal and photodynamic therapeutic efficiencies. Herein, by taking advantage of the interactions between CuS and DDTC, a new multifunctional nanoplatform based on DDTC-loaded CuS (CuS-DDTC) NDs is successfully fabricated, leading to the achievement of the synergistic effect of photothermal and copper enhanced chemotherapy. All experimental results verified promising synergistic therapeutic effects. Moreover, in vivo biocompatibility and metabolism experiments displayed that the CuS-DDTC NDs could be quickly excreted from the body with no apparent toxicity signs. Together, our findings indicated the superior synergistic therapeutic effect of photothermal and copper-enhanced chemotherapy, providing a promising anticancer strategy based on the CuS-DDTC NDs drug delivery system.