Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

Nanosafety: a Perspective on Nano-Bio Interactions

Engineered nanomaterials offer numerous benefits to society ranging from environmental remediation to biomedical applications such as drug or vaccine delivery as well as clean and cost-effective energy production and storage, and the promise of a more sustainable way of life. However, as nanomaterials of increasing sophistication enter the market, close attention to potential adverse effects on human health and the environment is needed. Here a critical perspective on nanotoxicological research is provided; the authors argue that it is time to leverage the knowledge regarding the biological interactions of nanomaterials to achieve a more comprehensive understanding of the human health and environmental impacts of these materials. Moreover, it is posited that nanomaterials behave like biological entities and that they should be regulated as such.

Approaches for reducing chemo/radiation-induced cardiotoxicity by nanoparticles

Nanoparticles are fascinating and encouraging carriers for cancer treatment due to their extraordinary properties and potential applications in targeted drug delivery, treatment, and diagnosis. Experimental studies including in vitro and in vivo examinations show that nanoparticles can cause a revolution in different aspects of cancer therapy. Normal tissue toxicity and early and late consequences are the major limitations of cancer therapy by radiotherapy and chemotherapy. However, the delivery of drugs into tumors or reducing the accumulation of drugs in normal tissues can permit a more satisfactory response of malignancies to therapy with more inferior side effects. Cardiac toxicity is one of the major problems for chemotherapy and radiotherapy. Therefore, several experimental studies have been performed to minimize the degenerative impacts of cancer treatment on the heart and also enhance the influences of radiotherapy and chemotherapy agents in cancers. This review article emphasizes the benefits of nanoparticle-based drug delivery techniques, including minimizing the exposure of the heart to anticancer drugs, enhancing the accumulation of drugs in cancers, and expanding the effectiveness of radiotherapy. The article also discusses the challenges and problems accompanied with nanoparticle-based drug delivery techniques such as toxicity, which need to be addressed through further research. Moreover, the article emphasizes the importance of developing safe and effective nanoparticle-based therapies that can be translated into clinical practice.

Modular Fabrication of Bioorthogonal Nanozymes for Biomedical Applications

The incorporation of transition metal catalysts (TMCs) into nanoscaffolds generates nanocatalysts that replicate key aspects of enzymatic behavior. The TMCs can access bioorthogonal chemistry unavailable to living systems. These bioorthogonal nanozymes can be employed as in situ "factories" for generating bioactive molecules where needed. The generation of effective bioorthogonal nanozymes requires co-engineering of the TMC and the nanometric scaffold. This review presents an overview of recent advances in the field of bioorthogonal nanozymes, focusing on modular design aspects of both nanomaterial and catalyst and how they synergistically work together for in situ uncaging of imaging and therapeutic agents.

Exploring the nano-wonders: unveiling the role of Nanoparticles in enhancing salinity and drought tolerance in plants

Plants experience diverse abiotic stresses, encompassing low or high temperature, drought, water logging and salinity. The challenge of maintaining worldwide crop cultivation and food sustenance becomes particularly serious due to drought and salinity stress. Sustainable agriculture has significant promise with the use of nano-biotechnology. Nanoparticles (NPs) have evolved into remarkable assets to improve agricultural productivity under the robust climate alteration and increasing drought and salinity stress severity. Drought and salinity stress adversely impact plant development, and physiological and metabolic pathways, leading to disturbances in cell membranes, antioxidant activities, photosynthetic system, and nutrient uptake. NPs protect the membrane and photosynthetic apparatus, enhance photosynthetic efficiency, optimize hormone and phenolic levels, boost nutrient intake and antioxidant activities, and regulate gene expression, thereby strengthening plant's resilience to drought and salinity stress. In this paper, we explored the classification of NPs and their biological effects, nanoparticle absorption, plant toxicity, the relationship between NPs and genetic engineering, their molecular pathways, impact of NPs in salinity and drought stress tolerance because the effects of NPs vary with size, shape, structure, and concentration. We emphasized several areas of research that need to be addressed in future investigations. This comprehensive review will be a valuable resource for upcoming researchers who wish to embrace nanotechnology as an environmentally friendly approach for enhancing drought and salinity tolerance.

Robust and Transparent Silver Oxide Coating Fabricated at Room Temperature Kills Clostridioides difficile Spores, MRSA, and Pseudomonas aeruginosa

Antimicrobial coatings can inhibit the transmission of infectious diseases when they provide a quick kill that is achieved long after the coating application. Here, we describe the fabrication and testing of a glass coating containing Ag2O microparticles that was prepared from sodium silicate at room temperature. The half-lives of both methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa on this coating are only 2-4 min. The half-life of Clostridioides difficile spores is about 9-12 min, which is extremely short for a spore. Additional tests on MRSA demonstrate that the coating retains its antimicrobial activity after abrasion and that an increased loading of Ag2O leads to a shorter half-life. This coating combines the properties of optical transparency, robustness, fast kill, and room temperature preparation that are highly desirable for an antimicrobial coating.

Tuning the Emulsion Properties Influences the Size of Poly(Caprolactone) Particles for Drug Delivery Applications

Advances in drug delivery have been accelerated with the addition of polymeric drug carriers. Direct delivery to a target site is a promising step in developing effective drug and gene therapies to treat disease. The efficacy of these drug carriers heavily relies on cell uptake without compromising critical cellular processes that promote cell viability. Drug release from biodegradable polymers is mediated largely by polymer degradation, and therefore the rate of polymer degradation dictates the feasibility of drug delivery applications. Traditionally, poly(caprolactone) (PCL) has only been used in long-term biomedical applications because the degradation time is much slower than other polymers. However, the biocompatibility of this polymer and the potential for longer delivery windows renders it a promising polymer candidate for drug delivery. In this work, we outline sixteen emulsion solvent evaporation preparation methods for PCL nanoparticles and microparticles to develop particles between 300 nm and 1.7 μm and with zeta potentials of -1.8 mV. We further investigated particles in a size range suitable for systemic tumor delivery and inhaled aerosol delivery to determine cell biocompatibility with the polymer in lung adenocarcinoma, endometrial adenocarcinoma, and human embryonic kidney cells. We determined these particles aren't detrimental to cell viability below particle monolayer coverage atop cells and therefore these formulations hold promise for the next stage of development as sustained-release drug delivery carriers.

Don't sweat the small stuff: a conversation about nanosafety

Bengt Fadeel and Phil Sayre discuss lessons learned with respect to the safety assessment of nanomaterials, and provide a perspective on current and future challenges.

Mechanobiological Analysis of Nanoparticle Toxicity

Nanoparticles (NPs) are commonly used in healthcare and nanotherapy, but their toxicity at high concentrations is well-known. Recent research has shown that NPs can also cause toxicity at low concentrations, disrupting various cellular functions and leading to altered mechanobiological behavior. While researchers have used different methods to investigate the effects of NPs on cells, including gene expression and cell adhesion assays, the use of mechanobiological tools in this context has been underutilized. This review emphasizes the importance of further exploring the mechanobiological effects of NPs, which could reveal valuable insights into the mechanisms behind NP toxicity. To investigate these effects, different methods, including the use of polydimethylsiloxane (PDMS) pillars to study cell motility, traction force production, and rigidity sensing contractions, have been employed. Understanding how NPs affect cell cytoskeletal functions through mechanobiology could have significant implications, such as developing innovative drug delivery systems and tissue engineering techniques, and could improve the safety of NPs for biomedical applications. In summary, this review highlights the significance of incorporating mechanobiology into the study of NP toxicity and demonstrates the potential of this interdisciplinary field to advance our knowledge and practical use of NPs.

In Situ-Forming Gels Loaded with Stimuli-Responsive Gated Mesoporous Silica Nanoparticles for Local Sustained Drug Delivery

A novel combination of in situ-forming hydrogels of hyaluronic acid with gated mesoporous materials was developed to design depots for local sustained release of chemotherapeutics. The depot consists of a hyaluronic-based gel loaded with redox-responsive mesoporous silica nanoparticles loaded with safranin O or doxorubicin and capped with polyethylene glycol chains containing a disulfide bond. The nanoparticles are able to deliver the payload in the presence of the reducing agent, glutathione (GSH), that promotes the cleavage of the disulfide bonds and the consequent pore opening and cargo delivery. Release studies and cellular assays demonstrated that the depot can successfully liberate the nanoparticles to the media and, subsequently, that the nanoparticles are internalized into the cells where the high concentration of GSH induces cargo delivery. When the nanoparticles were loaded with doxorubicin, a significant reduction in cell viability was observed. Our research opens the way to the development of new depots that enhance the local controlled release of chemotherapeutics by combining the tunable properties of hyaluronic gels with a wide range of gated materials.

Application of nanofibrous protein for the purification of contaminated water as a next generational sorption technology: a review

Globally, wastes from agricultural and industrial activities cause water pollution. Pollutants such as microbes, pesticides, and heavy metals in contaminated water bodies beyond their threshold limits result in several diseases like mutagenicity, cancer, gastrointestinal problems, and skin or dermal issues when bioaccumulated via ingestion and dermal contacts. Several technologies have been used in modern times to treat wastes or pollutants such as membrane purification technologies and ionic exchange methods. However, these methods have been recounted to be capital intensive, non-eco-friendly, and need deep technical know-how to operate thus, contributing to their inefficiencies and non-efficacies. This review work evaluated the application of Nanofibrils-protein for the purification of contaminated water. Findings from the study indicated that Nanofibrils protein is economically viable, green, and sustainable when used for water pollutant management or removal because they have outstanding recyclability of wastes without resulting in a secondary phase-pollutant. It is recommended to use residues from dairy industries, agriculture, cattle guano, and wastes from a kitchen in conjunction with nanomaterials to develop nanofibrils protein which has been recounted for the effective removal of micro and micropollutants from wastewater and water. The commercialization of nanofibrils protein for the purification of wastewater and water against pollutants has been tied to novel methods in nanoengineering technology, which depends strongly on the environmental impact in the aqueous ecosystem. So, there is a need to establish a legal framework for the establishment of a nano-based material for the effective purification of water against pollutants.

Nucleotide Interaction with Nanocrystalline Ceria Surface

The adsorption of nucleotides on the surface of nanocrystalline cerium dioxide (pHpzc = 6.3) in NaCl solutions was investigated using multi-batch adsorption experiments over a wide range of pH. The obtained results were interpreted as a formation of outer and inner sphere surface complexes with the participation of phosphate moieties. The Basic Stern surface complexation model was applied to obtain quantitative equilibrium reaction constants.

Silencing of proinflammatory NF-κB and inhibition of herpes simplex virus (HSV) replication by ultrasmall gold nanoparticles (2 nm) conjugated with small-interfering RNA

Azide-terminated ultrasmall gold nanoparticles (2 nm gold core) were covalently functionalized with alkyne-terminated small-interfering siRNA duplexes by copper-catalyzed azide-alkyne cycloaddition (CuAAC; click chemistry). The nanoparticle core was visualized by transmission electron microscopy. The number of attached siRNA molecules per nanoparticle was determined by a combination of atomic absorption spectroscopy (AAS; for gold) and UV-Vis spectroscopy (for siRNA). Each nanoparticle carried between 6 and 10 siRNA duplex molecules which corresponds to a weight ratio of siRNA to gold of about 2.2 : 1. Different kinds of siRNA were conjugated to the nanoparticles, depending on the gene to be silenced. In general, the nanoparticles were readily taken up by cells and highly efficient in gene silencing, in contrast to free siRNA. This was demonstrated in HeLa-eGFP cells (silencing of eGFP) and in LPS-stimulated macrophages (silencing of NF-κB). Furthermore, we demonstrated that nanoparticles carrying antiviral siRNA potently inhibited the replication of Herpes simplex virus 2 (HSV-2) in vitro. This highlights the strong potential of siRNA-functionalized ultrasmall gold nanoparticles in a broad spectrum of applications, including gene silencing and treatment of viral infections, combined with a minimal dose of gold.

Tuning ceria catalysts in aqueous media at the nanoscale: how do surface charge and surface defects determine peroxidase- and haloperoxidase-like reactivity

Designing the shape and size of catalyst particles, and their interfacial charge, at the nanometer scale can radically change their performance. We demonstrate this with ceria nanoparticles. In aqueous media, nanoceria is a functional mimic of haloperoxidases, a group of enzymes that oxidize organic substrates, or of peroxidases that can degrade reactive oxygen species (ROS) such as H₂O₂ by oxidizing an organic substrate. We show that the chemical activity of CeO_2-x nanoparticles in haloperoxidase- and peroxidase-like reactions scales with their active surface area, their surface charge, given by the ζ-potential, and their surface defects (via the Ce³⁺/Ce⁴⁺ ratio). Haloperoxidase-like reactions are controlled through the ζ-potential as they involve the adsorption of charged halide anions to the CeO₂ surface, whereas peroxidase-like reactions without charged substrates are controlled through the specific surface area S_BET. Mesoporous CeO_2-x particles, with large surface areas, were prepared via template-free hydrothermal reactions and characterized by small-angle X-ray scattering. Surface area, ζ-potential and the Ce³⁺/Ce⁴⁺ ratio are controlled in a simple and predictable manner by the synthesis time of the hydrothermal reaction as demonstrated by X-ray photoelectron spectroscopy, sorption and ζ-potential measurements. The surface area increased with synthesis time, whilst the Ce³⁺/Ce⁴⁺ ratio scales inversely with decreasing ζ-potential. In this way the catalytic activity of mesoporous CeO_2-x particles could be tailored selectively for haloperoxidase- and peroxidase-like reactions. The ease of tuning the surface properties of mesoporous CeO_2x particles by varying the synthesis time makes the synthesis a powerful general tool for the preparation of nanocatalysts according to individual needs.

Epigenetic tumor heterogeneity in the era of single-cell profiling with nanopore sequencing

Nanopore sequencing has brought the technology to the next generation in the science of sequencing. This is achieved through research advancing on: pore efficiency, creating mechanisms to control DNA translocation, enhancing signal-to-noise ratio, and expanding to long-read ranges. Heterogeneity regarding epigenetics would be broad as mutations in the epigenome are sensitive to cause new challenges in cancer research. Epigenetic enzymes which catalyze DNA methylation and histone modification are dysregulated in cancer cells and cause numerous heterogeneous clones to evolve. Detection of this heterogeneity in these clones plays an indispensable role in the treatment of various cancer types. With single-cell profiling, the nanopore sequencing technology could provide a simple sequence at long reads and is expected to be used soon at the bedside or doctor's office. Here, we review the advancements of nanopore sequencing and its use in the detection of epigenetic heterogeneity in cancer.

Copper uptake kinetics and toxicological effects of ionic Cu and CuO nanoparticles on the seaweed Ulva rigida

Copper ion (Cu²⁺) and copper oxide (CuO) nanoparticle (NP) ecotoxicity are of increasing concern as they are considered to be a potential risk to marine systems. This study represents the first attempt to evaluate CuO NP impacts on the seaweeds and Cu²⁺ on the chlorophyte Ulva rigida. Effects on oxidative stress, antioxidant defence markers, photosystem II function, thalli growth, and cell viability in U. rigida exposed for 4 up 72 h to1 and 5 mg L^-1 Cu²⁺ and CuO NPs were examined. Hydrogen peroxide (H₂O₂) generation, superoxide dismutase (SOD) activity, malondialdehyde (MDA) content, and growth inhibition seemed to be reliable and early warning markers of toxicity. The most important variables of the principal component analysis (PCA): H₂O₂ generation, antioxidant stress markers, and growth-based toxicity index, were higher at 1 mg L^-1 CuO NPs compared to CuSO₄ and at 5 mg L^-1 CuSO₄ compared to CuO NPs. Intracellular uptake kinetics fit well to the Michaelis-Menten equation. The higher toxicity at 5 mg L^-1 CuSO₄ compared to 1 mg L^-1 was due to the higher Cu uptake with increasing concentration, suggesting and higher accumulation ability. On the contrary, 1 mg L^-1 CuO NPs induced more strongly toxicity effects than 5 mg L^-1. The relatively stronger effect of CuO NPs at 1 mg L^-1 than the respective CuSO₄ concentration could be attributed to the higher rate of initial uptake (V_c) and the mean rate of Cu uptake [C_max/(2 × K_m)] at CuO NP treatment. The intracellular seaweed experimental threshold of Cu, which coincided with the onset of oxidative stress, was within the Cu concentration range recorded in Mediterranean Ulva spp., indicating that it may pose a substantial risk to marine environments.

Doxorubicin-loaded Mn-doped SiO2 nanospheres coated with carboxymethyl chitosan: fabrication, characterization, and in vitro evaluation

This work describes the preparation of manganese-doped mesoporous silica nanospheres via an in situ doping method. The results of scanning electron microscopy and N2 adsorption demonstrate that mesoporous silica possesses a spherical shape, a highly porous structure, a large specific surface area of 922.21 m2 g−1, and a pore volume of 0.257 cm3 g−1. The mesoporous silica nanocarrier is loaded with doxorubicin, and carboxymethyl chitosan encapsulation is performed to prevent doxorubicin leakage. The easy release characteristics of manganese under acidic conditions and the swelling properties of carboxymethyl chitosan endow the drug-loading system with an excellent pH/responsive release property. A cytotoxicity test shows that mesoporous silica nanospheres–doxorubicin–carboxymethyl chitosan had significant biocompatibility and enhanced cytotoxicity, thus revealing mesoporous silica nanospheres–doxorubicin–carboxymethyl chitosan as a promising delivery system.

Nanoparticles Influence Lytic Phage T4-like Performance In Vitro

Little is known about interactions of non-filamentous, complex-structured lytic phages and free, non-ordered nanoparticles. Emerging questions about their possible bio-sanitization co-applications or predictions of possible contact effects in the environment require testing. Therefore, we revealed the influence of various nanoparticles (NPs; SiO2, TiO2-SiO2, TiO2, Fe3O4, Fe3O4-SiO2 and SiO2-Fe3O4-TiO2) on a T4-like phage. In great detail, we investigated phage plaque-forming ability, phage lytic performance, phage progeny burst times and titers by the eclipse phase determinations. Additionally, it was proved that TEM micrographs and results of NP zeta potentials (ZP) were crucial to explain the obtained microbiological data. We propose that the mere presence of the nanoparticle charge is not sufficient for the phage to attach specifically to the NPs, consequently influencing the phage performance. The zeta potential values in the NPs are of the greatest influence. The threshold values were established at ZP < −35 (mV) for phage tail binding, and ZP > 35 (mV) for phage head binding. When NPs do not meet these requirements, phage−nanoparticle physical interaction becomes nonspecific. We also showed that NPs altered the phage lytic activity, regardless of the used NP concentration. Most of the tested nanoparticles positively influenced the phage lytic performance, except for SiO2 and Fe3O4-SiO2, with a ZP lower than −35 (mV), binding with the phage infective part—the tail.

Comprehensive Review on the Degradation Chemistry and Toxicity Studies of Functional Materials

In recent decades there has been growing interest of material chemists in the successful development of functional materials for drug delivery, tissue engineering, imaging, diagnosis, theranostic, and other biomedical applications with advanced nanotechnology tools. The efficacy and safety of functional materials are determined by their pharmacological, toxicological, and immunogenic effects. It is essential to consider all degradation pathways of functional materials and to assess plausible intermediates and final products for quality control. This review provides a brief insight into chemical degradation mechanisms of functional materials like oxidation, photodegradation, and physical and enzymatic degradation. The intermediates and products of degradation were confirmed with analytical methods such as proton nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC), UV-vis spectroscopy (UV-vis), infrared spectroscopy (IR), differential scanning calorimetry (DSC), mass spectroscopy, and other sophisticated analytical methods. These analytical methods are also used for regulatory, quality control, and stability purposes in industry. The assessment of degradation is important to predetermine the behavior of functional materials in specific storage conditions and can be relevant to their behavior during in vivo applications. Another important aspect is the evaluation of the toxicity of functional materials. Toxicity can be accessed with various methods using in vitro, in vivo, ex vivo, and in silico models. In vitro cell culture methods are used to determine mitochondrial damage, reactive oxygen species, stress responses, and cellular toxicity. In vitro cellular toxicity can be measured by MTT assay, LDH leakage assay, and hemolysis. In vivo studies are performed using various animal models involving zebrafish, rodents (mice and rats), and nonhuman primates. Ex vivo studies are also used for efficacy and toxicity determinations of functional materials like ex vivo potency assay and precision-cut liver slice (PCLS) models. The in silico tools with computational simulations like quantitative structure-activity relationships (QSAR), pharmacokinetics (PK) and pharmacodynamics (PD), dose and time response, and quantitative cationic-activity relationships ((Q)CARs) are used for prediction of the toxicity of functional materials. In this review, we studied the principle methods used for degradation studies, different degradation pathways, and mechanisms of functional material degradation with prototype examples. We discuss toxicity assessments with different toxicity approaches used for estimation of the safety and efficacy of functional materials.

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Copper oxide nanoparticles trigger macrophage cell death with misfolding of Cu/Zn superoxide dismutase 1 (SOD1)

Background

Copper oxide (CuO) nanoparticles (NPs) are known to trigger cytotoxicity in a variety of cell models, but the mechanism of cell death remains unknown. Here we addressed the mechanism of cytotoxicity in macrophages exposed to CuO NPs versus copper chloride (CuCl₂).

Methods

The mouse macrophage cell line RAW264.7 was used as an in vitro model. Particle uptake and the cellular dose of Cu were investigated by transmission electron microscopy (TEM) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. The deposition of Cu in lysosomes isolated from macrophages was also determined by ICP-MS. Cell viability (metabolic activity) was assessed using the Alamar Blue assay, and oxidative stress was monitored by a variety of methods including a luminescence-based assay for cellular glutathione (GSH), and flow cytometry-based detection of mitochondrial superoxide and mitochondrial membrane potential. Protein aggregation was determined by confocal microscopy using an aggresome-specific dye and protein misfolding was determined by circular dichroism (CD) spectroscopy. Lastly, proteasome activity was investigated using a fluorometric assay.

Results

We observed rapid cellular uptake of CuO NPs in macrophages with deposition in lysosomes. CuO NP-elicited cell death was characterized by mitochondrial swelling with signs of oxidative stress including the production of mitochondrial superoxide and cellular depletion of GSH. We also observed a dose-dependent accumulation of polyubiquitinated proteins and loss of proteasomal function in CuO NP-exposed cells, and we could demonstrate misfolding and mitochondrial translocation of superoxide dismutase 1 (SOD1), a Cu/Zn-dependent enzyme that plays a pivotal role in the defense against oxidative stress. The chelation of copper ions using tetrathiomolybdate (TTM) prevented cell death whereas inhibition of the cellular SOD1 chaperone aggravated toxicity. Moreover, CuO NP-triggered cell death was insensitive to the pan-caspase inhibitor, zVAD-fmk, and to wortmannin, an inhibitor of autophagy, implying that this was a non-apoptotic cell death. ZnO NPs, on the other hand, triggered autophagic cell death.

Conclusions

CuO NPs undergo dissolution in lysosomes leading to copper-dependent macrophage cell death characterized by protein misfolding and proteasomal insufficiency. Specifically, we present novel evidence for Cu-induced SOD1 misfolding which accords with the pronounced oxidative stress observed in CuO NP-exposed macrophages. These results are relevant for our understanding of the consequences of inadvertent human exposure to CuO NPs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00467-w.

Porous dynamic covalent polymers as promising reversal agents for heparin anticoagulants

Heparins are natural and partially degraded polyelectrolytes that consist of sulfated polysaccharide backbones. However, as clinically used anticoagulants, heparins are associated with clinical bleeding risks and thus require rapid neutralization. Protamine sulfate is the only clinically approved antidote for unfractionated heparin (UFH), which not only may cause severe adverse reactions in patients, but also is only partially effective against low molecular weight heparins (LMWHs). We here present the facile synthesis of four porous multicationic dynamic covalent polymers (DCPs) from the condensation of tritopic aldehyde and acylhydrazine precursors. We show that, as new water-soluble polymeric antidotes, the new DCPs can effectively include both UFH and LMWHs and thus reverse their anticoagulating activity, which is confirmed by the activated partial thromboplastin time and thromboelastographic assays as well as mouse tail transection assay (bleeding model). The neutralization activities of two of the DCPs were found to be overall superior to that of protamine and have wider concentration windows and good biocompatibility. This pore-inclusion neutralization strategy paves the way for the development of water-soluble polymers as universal heparin binding agents.

Highly accurate and label-free discrimination of single cancer cell using a plasmonic oxide-based nanoprobe

The detection of cancer cells at the single-cell level enables many novel functionalities such as next-generation cancer prognosis and accurate cellular analysis. While surface-enhanced Raman spectroscopy (SERS) has been widely considered as an effective tool in a low-cost and label-free manner, however, it is challenging to discriminate single cancer cells with an accuracy above 90% mainly due to the poor biocompatibility of the noble-metal-based SERS agents. Here, we report a dual-functional nanoprobe based on dopant-driven plasmonic oxides, demonstrating a maximum accuracy above 90% in distinguishing single THP-1 cell from peripheral blood mononuclear cell (PBMC) and human embryonic kidney (HEK) 293 from human macrophage cell line U937 based on their SERS patterns. Furthermore, this nanoprobe can be triggered by the bio-redox response from individual cells towards stimuli, empowering another complementary colorimetric cell detection, approximately achieving the unity discrimination accuracy at a single-cell level. Our strategy could potentially enable the future accurate and low-cost detection of cancer cells from mixed cell samples.

Photocontrolled chondrogenic differentiation and long-term tracking of mesenchymal stem cells in vivo by upconversion nanoparticles

Mesenchymal stem cells (MSCs) have multiple differentiation potentials and their clinical application is limited by controlled cell differentiation and long-term tracing in vivo. Here, we developed an upconversion nanoparticle (UCNP)-based nanoplatform for the photocontrolled chondrogenic differentiation and long-term tracking of MSCs in vivo. The UCNP nanoplatform could convert 980 nm near-infrared (NIR) light into UV/blue light (365/475 nm) and green/red light (545/647 nm) through Tm/Er doping. Then, the upconverted UV/blue light was used to drive the photosensitive molecule azobenzene (azo) that was modified in mesoporous silica to constantly change its conformation to trigger the release of kartogenin (KGN) from the UCNPs to induce the chondrogeni differentiation of MSCs, achieving photocontrolled cell differentiation. Both in vitro and in vivo experiments demonstrated the effective induction of chondrogenic differentiation in MSCs by NIR light with the UCNP nanoplatform incubation. In addition, after inducing differentiation, the UCNP nanoplatform that remained in the cytoplasm was used as a nanoprobe to monitor the MSCs in vitro and in vivo using the upconverted green/red light under the NIR light. Therefore, the UCNP nanoplatform displayed potential to be a powerful tool for the control of cell differentiation and the simultaneous long-term tracking of MSCs in vivo for regenerative medicine.

Design of a Controlled-Release Delivery Composite of Antibacterial Agent Gatifloxacin by Spherical Silica Nanocarrier

In this study, a spherical silica nanoparticle was explored as a gatifloxacin carrier synthesized by the chemical precipitation method. It was found that there was no new chemical bond formation during the loading process between gatifloxacin and silica, which implies that the binding was driven by physical interaction. In addition, the drug loading and encapsulation efficiency could be improved by appropriately increasing nano-silica content in the loading process. Meanwhile, the release rate of gatifloxacin after loading nano-silica was also improved, suggesting the successful design of a controlled-release delivery composite. The silica nanocarrier could significantly improve the antibacterial performance of Escherichia coli by 2.1 times, which was higher than the pure gatifloxacin. The 24 h bacteriostatic rate was higher than that of a simple mixture of silica nanoparticles and gatifloxacin. Strong reactive oxygen species (ROS) in GAT-SiO₂ NPs suggests that ROS might be associated with bactericidal activity. The synergy between the physicochemical effect and ROS production of this material is proposed as the mechanism of its antibacterial activity, which can also be confirmed by the cell membrane damage observed under electron microscopy and DNA damage experiments. Collectively, our finding indicates that nano-silica microspheres could serve as a promising carrier for the sustained release of gatifloxacin, thereby providing a new carrier design scheme for the improvement of the antibacterial effect.

Precise Subcellular Organelle Targeting for Boosting Endogenous-Stimuli-Mediated Tumor Therapy

Though numerous external-stimuli-triggered tumor therapies, including phototherapy, radiotherapy, and sonodynamic therapy have made great progress in cancer therapy, the low penetration depth of the laser, safety concerns of radiation, the therapeutic resistance, and the spatio-temporal constraints of the specific equipment restrict their convenient clinical applications. What is more, the inherent physiological barriers of the tumor microenvironment (TME), including hypoxia, heterogeneity, and high expression of antioxidant molecules also restrict the efficiency of tumor therapy. As a result, the development of nanoplatforms responsive to endogenous stimuli (such as glucose, acidic pH, cellular redox events, and etc.) has attracted great attention for starvation therapy, ion therapy, prodrug-mediated chemotherapy, or enzyme-catalyzed therapy. In addition, nanomedicines can be modified by some targeted units for precisely locating in subcellular organelles and boosting the destroying of tumor tissue, decreasing the dosage of nanoagents, reducing side effects, and enhancing the therapeutic efficiency. Herein, the properties of the TME, the advantages of endogenous stimuli, and the principles of subcellular-organelle-targeted strategies will be emphasized. Some necessary considerations for the exploitation of precision medicine and clinical translation of multifunctional nanomedicines in the future are also pointed out.

Silica-coated magnetic-nanoparticle-induced cytotoxicity is reduced in microglia by glutathione and citrate identified using integrated omics

BACKGROUND

Nanoparticles have been utilized in brain research and therapeutics, including imaging, diagnosis, and drug delivery, owing to their versatile properties compared to bulk materials. However, exposure to nanoparticles leads to their accumulation in the brain, but drug development to counteract this nanotoxicity remains challenging. To date, concerns have risen about the potential toxicity to the brain associated with nanoparticles exposure via penetration of the brain blood barrier to address this issue.

METHODS

Here the effect of silica-coated-magnetic nanoparticles containing the rhodamine B isothiocyanate dye [MNPs@SiO2(RITC)] were assessed on microglia through toxicological investigation, including biological analysis and integration of transcriptomics, proteomics, and metabolomics. MNPs@SiO2(RITC)-induced biological changes, such as morphology, generation of reactive oxygen species, intracellular accumulation of MNPs@SiO2(RITC) using transmission electron microscopy, and glucose uptake efficiency, were analyzed in BV2 murine microglial cells. Each omics data was collected via RNA-sequencing-based transcriptome analysis, liquid chromatography-tandem mass spectrometry-based proteome analysis, and gas chromatography- tandem mass spectrometry-based metabolome analysis. The three omics datasets were integrated and generated as a single network using a machine learning algorithm. Nineteen compounds were screened and predicted their effects on nanotoxicity within the triple-omics network.

RESULTS

Intracellular reactive oxygen species production, an inflammatory response, and morphological activation of cells were greater, but glucose uptake was lower in MNPs@SiO2(RITC)-treated BV2 microglia and primary rat microglia in a dose-dependent manner. Expression of 121 genes (from 41,214 identified genes), and levels of 45 proteins (from 5918 identified proteins) and 17 metabolites (from 47 identified metabolites) related to the above phenomena changed in MNPs@SiO2(RITC)-treated microglia. A combination of glutathione and citrate attenuated nanotoxicity induced by MNPs@SiO2(RITC) and ten other nanoparticles in vitro and in the murine brain, protecting mostly the hippocampus and thalamus.

CONCLUSIONS

Combination of glutathione and citrate can be one of the candidates for nanotoxicity alleviating drug against MNPs@SiO2(RITC) induced detrimental effect, including elevation of intracellular reactive oxygen species level, activation of microglia, and reduction in glucose uptake efficiency. In addition, our findings indicate that an integrated triple omics approach provides useful and sensitive toxicological assessment for nanoparticles and screening of drug for nanotoxicity.

Interaction of different-sized ZnO nanoparticles with maize (Zea mays): Accumulation, biotransformation and phytotoxicity

This study aimed to investigate the biotransformation of ZnO nanoparticles (NPs) in maize grown in hydroponics for ecotoxicity assessment. Maize seedlings grown for 14 days were exposed to a solution of 9 nm ZnO NPs, 40 nm ZnO NPs, and ZnSO₄ at a Zn concentration of 300 mg L^-1 for 1, 3, and 7 days, respectively. The results of in-situ Zn distribution in maize (Zea mays) showed that 9 nm ZnO NPs could quickly enter the roots of maize and reach the center column transport system of the stem. The results of transmission electron microscopy combined with energy dispersive X-ray spectroscopy revealed that ZnO NPs were accumulated in the vacuoles of the roots, and then transformed and transported through vesicles. Simulated studies showed that low pH (5.6) played a critical role in the transformation of ZnO NPs, and organic acids (K_f = 10^11.4) could promote particle dissolution. Visual MINTEQ software simulated the species of Zn after the entry of ZnO NPs or Zn²⁺ into plants and found that the species of Zn was mainly Zn²⁺ when the Zn content of plants reached 200-300 ppm. Considering that the lowest Zn content of the roots in treatments was 1920 mg kg^-1, combination of the result analysis of root effects showed that the toxicity of roots in most treatments had a direct relationship with Zn²⁺. However, treatment with 9 nm ZnO NPs exhibited significantly higher toxicity than ZnSO₄ treatment on day 1 when the Zn²⁺ concentration difference was not significant, which was mainly due to the large amount of ZnO NPs deposited in the roots. To the authors' knowledge, this study was the first to confirm the process of biotransformation and explore the factors affecting the toxicity of ZnO NPs in depth.

Titanium and Iron Oxide Nanoparticles for Cancer Therapy: Surface Chemistry and Biological Implications

Currently, cancer is among the most challenging diseases due to its ability to continuously evolve into a more complex muldimentional system, in addition to its high capability to spread to other organs and tissues. In this context, the relevance of nanobiomaterials (NBMs) for the development of new more effective and less harmful treatments is increasing. NBMs provide the possibility of combining several functionalities on a single system, expectedly in a synergic way, to better perform the treatment and cure. However, the control of properties such as colloidal stability, circulation time, pharmacokinetics, and biodistribution, assuring the concentration in specific target tissues and organs, while keeping all desired properties, tends to be dependent on subtle changes in surface chemistry. Hence, the behavior of such materials in different media/environments is of uttermost relevance and concern since it can compromise their efficiency and safety on application. Given the bright perspectives, many efforts have been focused on the development of nanomaterials fulfilling the requirements for real application. These include robust and reproducible preparation methods to avoid aggregation while preserving the interaction properties. The possible impact of nanomaterials in different forms of diagnosis and therapy has been demonstrated in the past few years, given the perspectives on how revolutionary they can be in medicine and health. Considering the high biocompatibility and suitability, this review is focused on titanium dioxide– and iron oxide–based nanoagents highlighting the current trends and main advancements in the research for cancer therapies. The effects of phenomena, such as aggregation and agglomeration, the formation of the corona layer, and how they can compromise relevant properties of nanomaterials and their potential applicability, are also addressed. In short, this review summarizes the current understanding and perspectives on such smart nanobiomaterials for diagnostics, treatment, and theranostics of diseases.

Analysis of Nanotoxicity with Integrated Omics and Mechanobiology

Nanoparticles (NPs) in biomedical applications have benefits owing to their small size. However, their intricate and sensitive nature makes an evaluation of the adverse effects of NPs on health necessary and challenging. Since there are limitations to conventional toxicological methods and omics analyses provide a more comprehensive molecular profiling of multifactorial biological systems, omics approaches are necessary to evaluate nanotoxicity. Compared to a single omics layer, integrated omics across multiple omics layers provides more sensitive and comprehensive details on NP-induced toxicity based on network integration analysis. As multi-omics data are heterogeneous and massive, computational methods such as machine learning (ML) have been applied for investigating correlation among each omics. This integration of omics and ML approaches will be helpful for analyzing nanotoxicity. To that end, mechanobiology has been applied for evaluating the biophysical changes in NPs by measuring the traction force and rigidity sensing in NP-treated cells using a sub-elastomeric pillar. Therefore, integrated omics approaches are suitable for elucidating mechanobiological effects exerted by NPs. These technologies will be valuable for expanding the safety evaluations of NPs. Here, we review the integration of omics, ML, and mechanobiology for evaluating nanotoxicity.

Current Progress of Magnetoresistance Sensors

Magnetoresistance (MR) is the variation of a material’s resistivity under the presence of external magnetic fields. Reading heads in hard disk drives (HDDs) are the most common applications of MR sensors. Since the discovery of giant magnetoresistance (GMR) in the 1980s and the application of GMR reading heads in the 1990s, the MR sensors lead to the rapid developments of the HDDs’ storage capacity. Nowadays, MR sensors are employed in magnetic storage, position sensing, current sensing, non-destructive monitoring, and biomedical sensing systems. MR sensors are used to transfer the variation of the target magnetic fields to other signals such as resistance change. This review illustrates the progress of developing nanoconstructed MR materials/structures. Meanwhile, it offers an overview of current trends regarding the applications of MR sensors. In addition, the challenges in designing/developing MR sensors with enhanced performance and cost-efficiency are discussed in this review.

Advances in super-resolution fluorescence microscopy for the study of nano-cell interactions

Understanding the interactions between nanomaterials and biological systems plays an essential role in enhancing the efficacy of nanomedicines and deepening the understanding of the biological domain. Fluorescence microscopy is a powerful optical imaging technique that allows direct visualization of the behavior of fluorescent-labeled nanomaterials in the intracellular microenvironment. However, conventional fluorescence microscopy, such as confocal microscopy, has limited optical resolution due to the diffraction of light and therefore cannot provide the precise details of nanomaterials with diameters of less than ∼250 nm. Fortunately, the development of super-resolution fluorescence microscopy has overcome the resolution limitation, enabling more comprehensive studies of nano-cell interactions. Herein, we have summarized the recent advances in nano-cell interactions investigated by a variety of super-resolution microscopic techniques, which may benefit researchers in this multi-disciplinary area by providing a guideline to select appropriate platforms for studying materiobiology.

Enhanced Apoptosis by Functionalized Highly Reduced Graphene Oxide and Gold Nanocomposites in MCF-7 Breast Cancer Cells

Graphene nanocomposites have gained significant interest in a variety of biological applications due to their unique properties. Herein, we have studied the apoptosis-inducing ability and anticancer properties of functionalized highly reduced graphene oxide (HRG) and gold nanoparticles (Au NPs)-based nanocomposites (AP-HRG-Au). Samples were prepared under facile conditions via simple stirring and ultrasonication. All the samples were tested for their anticancer properties against different human cancer cell lines including lung (A549), liver (HepG2), and breast (MCF-7) cancer cells using doxorubicin as a positive control. In order to enhance the solubility and bioavailability of the sample, HRG was functionalized with 1-aminopyrene (1-AP) as a stabilizing ligand. The ligand also facilitated the homogeneous growth of Au NPs on the surface of HRG by offering chemically specific binding sites. The synthesis of nanocomposites and the surface functionalization of HRG were confirmed by UV-Vis, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The structure and morphology of the as-prepared nanocomposites were established by high-resolution transmission electron microscopy. Because of the functionalization, the AP-HRG-Au nanocomposite exhibited enhanced physical stability and high dispersibility. A comparative anticancer study of pristine HRG, nonfunctionalized HRG-Au, and 1-AP-functionalized AP-HRG-Au nanocomposites revealed the enhanced apoptosis ability of functionalized nanocomposites compared to the nonfunctionalized sample, whereas the pristine HRG did not show any anticancer ability against all tested cell lines. Both HRG-Au and AP-HRG-Au have induced a concentration-dependent reduction in cell viability in all tested cell lines after 48 h of exposure, with a significantly higher response in MCF-7 cells compared to the remaining cells. Therefore, MCF-7 cells were selected to perform detailed investigations using apoptosis assay, cell cycle analysis, and reactive oxygen species measurements. These results suggest that AP-HRG-Au induces enhanced apoptosis in human breast cancer cells.

Biological and Medical Applications of Calcium Phosphate Nanoparticles

Calcium phosphate nanoparticles have a high biocompatibility and biodegradability due to their chemical similarity to human hard tissue, for example, bone and teeth. They can be used as efficient carriers for different kinds of biomolecules such as nucleic acids, proteins, peptides, antibodies, or drugs, which alone are not able to enter cells where their biological effect is required. They can be loaded with cargo molecules by incorporating them, unlike solid nanoparticles, and also by surface functionalization. This offers protection, for example, against nucleases, and the possibility for cell targeting. If such nanoparticles are functionalized with fluorescing dyes, they can be applied for imaging in vitro and in vivo. Synthesis, functionalization and cell uptake mechanisms of calcium phosphate nanoparticles are discussed together with applications in transfection, gene silencing, imaging, immunization, and bone substitution. Biodistribution data of calcium phosphate nanoparticles in vivo are reviewed.

Measuring Cellular Uptake of Polymer Dots for Quantitative Imaging and Photodynamic Therapy

There is a great deal of interest in the development of nanoparticles for biomedicine. The question of how many nanoparticles are taken up by cells is important for biomedical applications. Here, we describe a fluorescence method for the quantitative measurement of the cellular uptake of polymer dots (Pdots) and a further estimation of intracellular Pdots photosensitizer for fluorescence imaging and photodynamic therapy. The approach relies on the high brightness, excellent stability, minimal aggregation quenching, and metalloporphyrin doping properties of the Pdots. We correlated the single-cell fluorescence brightness obtained from fluorescence spectrometry, confocal microscopy, and flow cytometry with the number of endocytosed Pdots, which was validated by inductively coupled plasma mass spectrometry. Our results indicated that, on average, ∼1.3 million Pdots were taken up by single cells that were incubated for 4 h with arginine 8-Pdots (40 μg/mL, ∼20 nm diameter). The absolute number of endocytosed Pdots of individual cells could be estimated from confocal microscopy by comparing the single-cell brightness with the average intensity. Furthermore, we investigated the cell viability as a result of an intracellular Pdots photosensitizer, from which the half maximal inhibitory concentration was determined to be ∼7.2 × 10⁵ Pdots per cell under the light dose of 60 J/cm². This study provides an effective method for quantifying endocytosed Pdots, which can be extended to investigate the cellular uptake of various conjugated polymer carriers in biomedicine.

Resistance and Adaptation of Bacteria to Non-Antibiotic Antibacterial Agents: Physical Stressors, Nanoparticles, and Bacteriophages

Antimicrobial resistance is a significant threat to human health worldwide, forcing scientists to explore non-traditional antibacterial agents to support rapid interventions and combat the emergence and spread of drug resistant bacteria. Many new antibiotic-free approaches are being developed while the old ones are being revised, resulting in creating unique solutions that arise at the interface of physics, nanotechnology, and microbiology. Specifically, physical factors (e.g., pressure, temperature, UV light) are increasingly used for industrial sterilization. Nanoparticles (unmodified or in combination with toxic compounds) are also applied to circumvent in vivo drug resistance mechanisms in bacteria. Recently, bacteriophage-based treatments are also gaining momentum due to their high bactericidal activity and specificity. Although the number of novel approaches for tackling the antimicrobial resistance crisis is snowballing, it is still unclear if any proposed solutions would provide a long-term remedy. This review aims to provide a detailed overview of how bacteria acquire resistance against these non-antibiotic factors. We also discuss innate bacterial defense systems and how bacteriophages have evolved to tackle them.

Development of a New Polymeric Nanocarrier Dedicated to Controlled Clozapine Delivery at the Dopamine D2-Serotonin 5-HT1A Heteromers

Clozapine, the second generation antipsychotic drug, is one of the prominent compounds used for treatment of schizophrenia. Unfortunately, use of this drug is still limited due to serious side effects connected to its unspecific and non-selective action. Nevertheless, clozapine still remains the first-choice drug for the situation of drug-resistance schizophrenia. Development of the new strategy of clozapine delivery into well-defined parts of the brain has been a great challenge for modern science. In the present paper we focus on the presentation of a new nanocarrier for clozapine and its use for targeted transport, enabling its interaction with the dopamine D₂ and serotonin 5-HT_1A heteromers (D₂-5-HT_1A) in the brain tissue. Clozapine polymeric nanocapsules (CLO-NCs) were prepared using anionic surfactant AOT (sodium docusate) as an emulsifier, and bio-compatible polyelectrolytes such as: poly-l-glutamic acid (PGA) and poly-l-lysine (PLL). Outer layer of the carrier was grafted by polyethylene glycol (PEG). Several variants of nanocarriers containing the antipsychotic varying in physicochemical parameters were tested. This kind of approach may enable the availability and safety of the drug, improve the selectivity of its action, and finally increase effectiveness of schizophrenia therapy. Moreover, the purpose of the manuscript is to cover a wide scope of the issues, which should be considered while designing a novel means for drug delivery. It is important to determine the interactions of a new nanocarrier with many cell components on various cellular levels in order to be sure that the new nanocarrier will be safe and won’t cause undesired effects for a patient.

Composition of Intracellular Protein Corona around Nanoparticles during Internalization

It has been well established that the early-stage interactions of nanoparticles with cells are governed by the extracellular protein corona. However, after entering into the cells, the evolving protein corona is the key to subsequent processing of nanoparticles by cells. To identify the protein corona around intracellular nanoparticles, it is essential to maintain its original compositions during cell treatment. Herein, we develop a paraformaldehyde (PFA) cross-linking strategy to stabilize corona compositions when extracting protein coronas from cells, providing original information on protein coronas around intercellular gold nanoparticles (AuNPs). The stability of the protein corona after PFA cross-linking was carefully investigated with several characterization methods, and the results demonstrate that PFA cross-linking successfully prevents the dissociation and exchange of corona proteins. Then the recovered intracellular protein corona around AuNPs from living HepG2 cells with a PFA cross-linking strategy was subjected to nanoHPLC-MS/MS for proteomic analysis. It was found that the compositions of intracellular protein coronas are dominated by cell-derived proteins and undergo significant variation of protein species and amounts over time during internalization. Time-resolved analysis provides relevant proteins involved in nanoparticle cellular uptake and transportation, indicating that AuNPs are endocytosed mainly by a clathrin-mediated uptake mechanism and directed into an endolysosomal pathway toward their final destination. Such proteomic-based results are verified by pharmacological inhibition and TEM imaging analysis. This work provides a universal strategy to study compositions of protein corona around intercellular nanoparticles and could be a footstone to link the formation of protein corona around nanoparticles to their biological function in cells.