Transmission Electron Microscopy as a Powerful Tool to Investigate the Interaction of Nanoparticles with Subcellular Structures

Raman microscopy allows to follow internalization, subcellular accumulation and fate of iron oxide nanoparticles in cells

An important issue in the context of both potenial toxicity of iron oxide nanoparticles (IONP) and their medical applications is tracking of the internalization process of these nanomaterials into living cells, as well as their localization and fate within them. The typical methods used for this purpose are transmission electron microscopy, confocal fluorescence microscopy as well as light-scattering techniques including dark-field microscopy and flow cytometry. All the techniques mentioned have their advantages and disadvantages. Among the problems it is necessary to mention complicated sample preparation, difficult interpretation of experimental data requiring qualified and experienced personnel, different behavior of fluorescently labeled IONP comparing to those label-free or finally the lack of possibility of chemical composition characteristics of nanomaterials. The purpose of the present investigation was the assessment of the usefulness of Raman microscopy for the tracking of the internalization of IONP into cells, as well as the optimization of this process. Moreover, the study focused on identification of the potential differences in the cellular fate of superparamagnetic nanoparticles having magnetite and maghemite core. The Raman spectra of U87MG cells which internalized IONP presented additional bands which position depended on the used laser wavelength. They occurred at the wavenumber range 1700-2400 cm-1 for laser 488 nm and below the wavenumber of 800 cm-1 in case of laser 532 nm. The intensity of the mentioned Raman bands was higher for the green laser (532 nm) and their position, was independent and not characteristic on the primary core material of IONP (magnetite, maghemite). The obtained results showed that Raman microscopy is an excellent, non-destructive and objective technique that allows monitoring the process of internalization of IONP into cells and visualizing such nanoparticles and/or their metabolism products within them at low exposure levels. What is more, the process of tracking IONP using the technique may be further improved by using appropriate wavelength and power of the laser source.

Self-micellizing solid dispersion of thymoquinone with enhanced biopharmaceutical and nephroprotective effects

The present study was designed to develop a self-micellizing solid dispersion (SMSD) containing Thymoquinone (TQM), a phytonutrient obtained from Nigella sativa seeds, aiming to improve its biopharmaceutical and nephroprotective functions. The apparent solubility of TQM in polymer solutions was used to choose an appropriate amphiphilic polymer that could be used to make an SMSD system. Based on the apparent solubility, Soluplus® was selected as an appropriate carrier, and mixing with TQM, SMSD-TQM with different loadings of TQM (5-15%) was made by solvent evaporation and freeze-drying techniques, respectively, and the formulations were optimized. The optimized SMSD-TQM was evaluated in terms of particle size distribution, morphology, release characteristics, pharmacokinetic behavior, and nephroprotective effects in a rat model of acute kidney injury. SMSD-TQM significantly improved the dissolution characteristics (97.8%) of TQM in water within 60 min. Oral administration of SMSD-TQM in rats exhibited a 4.9-fold higher systemic exposure than crystalline TQM. In a cisplatin-induced (6 mg/kg, i.p.) acute kidney-damaged rat model, oral SMSD-TQM (10 mg/kg) improved the nephroprotective effects of TQM based on the results of kidney biomarkers and histological abnormalities. These findings suggest that SMSD-TQM might be efficacious in enhancing the nephroprotective effect of TQM by overcoming biopharmaceutical limitations.

Current insights into the green synthesis, in planta characterization and phytoeffects of nickel nanoparticles and their agricultural implications

The intensifying production and release into the environment as well as the increasing potential in agricultural applications make the relationship between plants and nickel nanoparticles (Ni NPs) a relevant and timely topic. The aim of this review is to give an overview and discuss the latest findings about the relationship of Ni NPs and plants. Ni NPs can be synthesized using phytochemicals derived from plant parts in an environmentally friendly manner. There are several ways for these nanoparticles to enter plant cells and tissues. This can be demonstrated through various imaging and chemical mapping approaches (e.g., transmission electron microscopy, X-ray fluorescence spectroscopy etc.). NiO NPs affect plants at multiple levels, including subcellular, cellular, tissue, organ, and whole-plant levels. However, the effects of Ni NPs on plants' ecological partners (e.g., rhizobiome, pollinators) remain largely unknown despite their ecotoxicological significance. The main cause of the Ni NPs-triggered damages is the reactive oxygen species imbalance as a consequence of the modulation of antioxidants. In non-tolerant plants, the toxicity of NiO NPs can be mitigated by exogenous treatments such as the application of silicon, salicylic acid, or jasmonic acid, which induce defense mechanisms whereas Ni-hypertolerant plant species possess endogenous defense systems, such as cell wall modifications and nitrosative signaling against NiO NP stress. Research highlights the role of Ni NPs in managing fungal diseases, showcasing their antifungal properties against specific pathogens. Due to the essentiality of Ni, the application of Ni NPs as nanofertilizers might be promising and has recently started to come into view.

Metal-Based Drug-DNA Interactions and Analytical Determination Methods

DNA structure has many potential places where endogenous compounds and xenobiotics can bind. Therefore, xenobiotics bind along the sites of the nucleic acid with the aim of changing its structure, its genetic message, and, implicitly, its functions. Currently, there are several mechanisms known to be involved in DNA binding. These mechanisms are covalent and non-covalent interactions. The covalent interaction or metal base coordination is an irreversible binding and it is represented by an intra-/interstrand cross-link. The non-covalent interaction is generally a reversible binding and it is represented by intercalation between DNA base pairs, insertion, major and/or minor groove binding, and electrostatic interactions with the sugar phosphate DNA backbone. In the present review, we focus on the types of DNA-metal complex interactions (including some representative examples) and on presenting the methods currently used to study them.

The impact of macrophage phenotype and heterogeneity on the total internalized gold nanoparticle counts

Macrophages play a pivotal role in the internalization and processing of administered nanoparticles (NPs). Furthermore, the phagocytic capacity and immunological properties of macrophages can vary depending on their microenvironment, exhibiting a spectrum of polarization states ranging from pro-inflammatory M1 to anti-inflammatory M2. However, previous research investigating this phenotype-dependent interaction with NPs has predominantly relied on semi-quantitative techniques or conventional metrics to assess intracellular NPs. Here, we focus on the interaction of human monocyte-derived macrophage phenotypes (M1-like and M2-like) with gold NPs (AuNPs) by combining population-based metrics and single-cell analysis by focused ion beam-scanning electron microscopy (FIB-SEM). The multimodal analysis revealed phenotype-dependent response and uptake behavior differences, becoming more pronounced after 48 hours. The study also highlighted phenotype-dependent cell-to-cell heterogeneity in AuNPs uptake and variability in particle number at the single-cell level, which was particularly evident in M2-like macrophages, which increases with time, indicating enhanced heteroscedasticity. Future efforts to design NPs targeting macrophages should consider the phenotypic variations and the distribution of NPs concentrations within a population, including the influence of cell-to-cell heterogeneity. This comprehensive understanding will be critical in developing safe and effective NPs to target different macrophage phenotypes.

Precise tracking of nanoparticles in plant roots

One of the foremost challenges in nanobiotechnology is obtaining direct evidence of nanoparticles' absorption and internalization in plants. Although confocal laser scanning microscopy (CLSM) or transmission electron microscopy (TEM) are currently the most commonly used tools to characterize nanoparticles in plants, subjectivity of researchers, incorrect sample handling, inevitable fluorescence leakage and limitations of imaging instruments lead to false positives and non-reproducibility of experimental results. This protocol provides an easy-to-operate dual-step method, combining CLSM for macroscopic tissue examination and TEM for cellular-level analysis, to effectively trace single particles in plant roots with accuracy and precision. In addition, we also provide detailed methods for processing plant materials before imaging, including cleaning, and staining, to maximize the accuracy and reliability of imaging. This protocol involves currently commonly used nanomaterial types, such as metal-based and doped carbon-based materials, and enables accurate localization of nanoparticles with different sizes at the cell level in Arabidopsis thaliana root samples either through contrast or element mapping analysis. It serves as a valuable reference and benchmark for scholars in plant science, chemistry and environmental studies to understand the interaction between plant roots and nanomaterials and to detect the distribution of nanomaterials in plants. Excluding plant culture time, the protocol can be completed in 4-5 d.

Nanoparticle-plant interactions: Physico-chemical characteristics, application strategies, and transmission electron microscopy-based ultrastructural insights, with a focus on stereological research

Ensuring global food security is pressing among challenges like population growth, climate change, soil degradation, and diminishing resources. Meeting the rising food demand while reducing agriculture's environmental impact requires innovative solutions. Nanotechnology, with its potential to revolutionize agriculture, offers novel approaches to these challenges. However, potential risks and regulatory aspects of nanoparticle (NP) utilization in agriculture must be considered to maximize their benefits for human health and the environment. Understanding NP-plant cell interactions is crucial for assessing risks of NP exposure and developing strategies to control NP uptake by treated plants. Insights into NP uptake mechanisms, distribution patterns, subcellular accumulation, and induced alterations in cellular architecture can be effectively drawn using transmission electron microscopy (TEM). TEM allows direct visualization of NPs within plant tissues/cells and their influence on organelles and subcellular structures at high resolution. Moreover, integrating TEM with stereological principles, which has not been previously utilized in NP-plant cell interaction assessments, provides a novel and quantitative framework to assess these interactions. Design-based stereology enhances TEM capability by enabling precise and unbiased quantification of three-dimensional structures from two-dimensional images. This combined approach offers comprehensive data on NP distribution, accumulation, and effects on cellular morphology, providing deeper insights into NP impact on plant physiology and health. This report highlights the efficient use of TEM, enhanced by stereology, in investigating diverse NP-plant tissue/cell interactions. This methodology facilitates detailed visualization of NPs and offers robust quantitative analysis, advancing our understanding of NP behavior in plant systems and their potential implications for agricultural sustainability.

Green synthesis and characterization of AgNPs, liposomal loaded AgNPs and ZnPcS4 photosensitizer for enhanced photodynamic therapy effects in MCF-7 breast cancer cells

Breast cancer remains a formidable challenge in oncology despite significant advancements in treatment modalities. Conventional therapies such as surgery, chemotherapy, radiation therapy, and hormonal therapy have been the mainstay in managing breast cancer for decades. However, a subset of patient's experiences treatment failure, leading to disease recurrence and progression. Therefore, this study investigates the therapeutic potential of green-synthesized silver nanoparticles (AgNPs) using an African medicinal plant (Dicoma anomala methanol root extract) as a reducing agent for combating breast cancer. AgNPs were synthesized using the bottom-up approach and later modified with liposomes (Lip) loaded with photosensitizer (PS) zinc phthalocyanine tetrasulfonate (Lip@ZnPcS4) using thin film hydration method. The successful formation and Lip modification of AgNPs, alongside ZnPcS4, were confirmed through various analytical techniques including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Following a 24 h treatment period, MCF-7 cells were assessed for viability using 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT viability assay), cell death analysis using mitochondrial membrane potential (MMP) (ΔΨm), Annexin V-fluorescein isothiocyanate (FITC)-propidium iodide (PI) kit, and caspase- 3, 8 and 9 activities. The experiments were repeated four times (n = 4), and the results were analyzed using SPSS statistical software version 27, with a confidence interval set at 0.95. The synthesized nanoparticles and nanocomplex, including AgNPs, AgNPs-Lip, Lip@ZnPcS4, and AgNPs-Lip@ZnPcS4, exhibited notable cytotoxicity and therapeutic efficacy against MCF-7 breast cancer cells. Notably, the induction of apoptosis, governed by the upregulation of apoptotic proteins i.e., caspase 8 and 9 activities. In addition, caspase 3 was not expressed by MCF-7 cells in both control and experimental groups. Given the challenging prognosis associated with breast cancer, the findings underscore the promise of liposomal nanoformulations in cancer photodynamic therapy (PDT), thus warranting further exploration in clinical settings.

Histochemistry for Molecular Imaging in Nanomedicine

All the nanotechnological devices designed for medical purposes have to deal with the common requirement of facing the complexity of a living organism. Therefore, the development of these nanoconstructs must involve the study of their structural and functional interactions and the effects on cells, tissues, and organs, to ensure both effectiveness and safety. To this aim, imaging techniques proved to be extremely valuable not only to visualize the nanoparticles in the biological environment but also to detect the morphological and molecular modifications they have induced. In particular, histochemistry is a long-established science able to provide molecular information on cell and tissue components in situ, bringing together the potential of biomolecular analysis and imaging. The present review article aims at offering an overview of the various histochemical techniques used to explore the impact of novel nanoproducts as therapeutic, reconstructive and diagnostic tools on biological systems. It is evident that histochemistry has been playing a leading role in nanomedical research, being largely applied to single cells, tissue slices and even living animals.

Rapid cellular uptake of citrate-coated iron oxide nanoparticles unaffected by cell-surface glycosaminoglycans

Citrate-coated iron oxide nanoparticles, specifically Synomag®-COOH (SynC), are promising tracers in magnetic particle imaging (MPI) due to their high magnetic moments and rapid cellular uptake. The mechanisms driving efficient SynC uptake remain unclear. Previous observations suggest a role of the extracellular glycocalyx during nanoparticle uptake. Here, we ascertain whether the cell-surface glycosaminoglycans (GAGs) regulate the uptake of SynC. Using transmission electron microscopy (TEM), we visualized SynC uptake by THP-1 cells, a human acute monocytic leukemia cell line. We investigated the interaction of SynC with GAGs in living cells using click-chemistry-based labeling. Upon treating THP-1 cells with chondroitinase or hyaluronidase and with a xylosyltransferase-deficient cell line, we quantified SynC uptake and measured interactions of SynC with cells in real time using magnetic particle spectroscopy (MPS). The THP-1 cell membrane engulfed or formed extensions around SynC, indicating uptake through pinocytosis and phagocytosis. We measured an increased MPS signal of SynC within seconds of cell contact, suggesting an interaction with extracellular components like the glycocalyx. Upon adding SynC to THP-1 cells, we could not observe disruption of fluorescently labeled GAGs or an enhanced intracellular fluorescence, implying that SynC does not accelerate the turnover of GAGs by binding. Lack of chondroitin sulfate, heparan sulfate, and hyaluronic acid did not affect the rapid magnetic behavior increase of SynC upon cell contact. Accordingly, we measured no significant differences in SynC uptake between wild type cells and our GAG-deficient models. These findings suggest that GAGs act as a permeable bandpass for SynC nanoparticles with a minor negative surface charge of -13.8 mV. This finding has significant implications for MPI-based cell tracking because it facilitates efficient tracking of cell types that lack a strong repulsion by cell-surface GAGs. It will be crucial to investigate whether the rapid uptake of SynC is cell-type specific and influenced by different extracellular matrix compositions.

Elucidating bacterial coaggregation through a physicochemical and imaging surface characterization

Bacterial coaggregation is a highly specific type of cell-cell interaction, well-documented among oral bacteria, and involves specific characteristics of the cell surface of the coaggregating strains. However, the understanding of the mechanisms promoting coaggregation in aquatic systems remains limited. This gap is critical to address, given the broad implications of coaggregation for multispecies biofilm formation, water quality, the performance of engineered systems, and diverse biotechnological applications. Therefore, this study aims to comprehensively characterize the cell surface of the coaggregating strain Delftia acidovorans 005P, isolated from drinking water, alongside a non-coaggregating strain, D. acidovorans 009P. By analyzing two strains of the same species, we aim to identify the factors contributing to the coaggregation ability of strain 005P. To achieve this, we employed a combination of physicochemical characterization, Fourier-transform infrared spectroscopy (FTIR), and advancing imaging techniques [transmission electron microscopy and cryo-electron tomography (cryo-ET)]. The coaggregating strain (005P) exhibited higher surface hydrophobicity, negative surface charge, and cell surface and co-adhesion energies than the non-coaggregating strain (009P). The chemical characterization of bacterial surfaces through FTIR revealed subtle differences, particularly in spectral regions linked to carbohydrates and phosphodiesters/amide III of proteins (860-930 cm-1 and 1212-1240 cm-1, respectively). Cryo-ET highlighted significant differences in pili structures between the strains, such as variations in length, frequency, and arrangement. The pili in the 005P strain, identified as pili-like adhesins, serve as key mediators of coaggregation. By integrating physicochemical analyses and high-resolution imaging techniques, this study conclusively links the coaggregation ability of D. acidovorans 005P to its unique pili characteristics, emphasizing their crucial role in microbial coaggregation in aquatic environments.

Human Umbilical Vein Endothelial Cells as a Versatile Cellular Model System in Diverse Experimental Paradigms: An Ultrastructural Perspective

Human umbilical vein endothelial cells (HUVECs) are primary cells isolated from the vein of an umbilical cord, extensively used in cardiovascular studies and medical research. These cells, retaining the characteristics of endothelial cells in vivo, serve as a valuable cellular model system for understanding vascular biology, endothelial dysfunction, pathophysiology of diseases such as atherosclerosis, and responses to different drugs or treatments. Transmission electron microscopy (TEM) has been a cornerstone in revealing the detailed architecture of multiple cellular model systems including HUVECs, allowing researchers to visualize subcellular organelles, membrane structures, and cytoskeletal elements. Among them, the endoplasmic reticulum, Golgi apparatus, mitochondria, and nucleus can be meticulously examined to recognize alterations indicative of cellular responses to various stimuli. Importantly, Weibel-Palade bodies are characteristic secretory organelles found in HUVECs, which can be easily distinguished in the TEM. These distinctive structures also dynamically react to different factors through regulated exocytosis, resulting in complete or selective release of their contents. This detailed review summarizes the ultrastructural features of HUVECs and highlights the utility of TEM as a pivotal tool for analyzing HUVECs in diverse research frameworks, contributing valuable insights into the comprehension of HUVEC behavior and enriching our knowledge into the complexity of vascular biology.

Definition, detection, and tracking of nanowaste in foods: Challenges and perspectives

Commercial applications of nanotechnology in the food industry are rapidly increasing. Accordingly, there is a simultaneous increase in the amount and diversity of nanowaste, which arise as byproducts in the production, use, disposal, or recycling processes of nanomaterials utilized in the food industry. The potential risks of this nanowaste to human health and the environment are alarming. It is of crucial significance to establish analytical methods and monitoring systems for nanowaste to ensure food safety. This review provides comprehensive information on nanowaste in foods as well as comparative material on existing and new analytical methods for the detection of nanowaste. The article is specifically focused on nanowaste in food systems. Moreover, the current techniques, challenges as well as potential use of new and progressive methods are underlined, further highlighting advances in technology, collaborative efforts, as well as future perspectives for effective nanowaste detection and tracking. Such detection and tracking of nanowaste are required in order to effectively manage this type ofwasted in foods. Although there are devices that utilize spectroscopy, spectrometry, microscopy/imaging, chromatography, separation/fractionation, light scattering, diffraction, optical, adsorption, diffusion, and centrifugation methods for this purpose, there are challenges to be overcome in relation to nanowaste as well as food matrix and method characteristics. New technologies such as radio-frequency identification, Internet of things, blockchain, data analytics, and machine learning are promising. However, the cooperation of international organizations, food sector, research, and political organizations is needed for effectively managing nanowaste. Future research efforts should be focused on addressing knowledge gaps and potential strategies for optimizing nanowaste detection and tracking processes.

Achieving Endo/Lysosomal Escape Using Smart Nanosystems for Efficient Cellular Delivery

The delivery of therapeutic agents faces significant hurdles posed by the endo-lysosomal pathway, a bottleneck that hampers clinical effectiveness. This comprehensive review addresses the urgent need to enhance cellular delivery mechanisms to overcome these obstacles. It focuses on the potential of smart nanomaterials, delving into their unique characteristics and mechanisms in detail. Special attention is given to their ability to strategically evade endosomal entrapment, thereby enhancing therapeutic efficacy. The manuscript thoroughly examines assays crucial for understanding endosomal escape and cellular uptake dynamics. By analyzing various assessment methods, we offer nuanced insights into these investigative approaches' multifaceted aspects. We meticulously analyze the use of smart nanocarriers, exploring diverse mechanisms such as pore formation, proton sponge effects, membrane destabilization, photochemical disruption, and the strategic use of endosomal escape agents. Each mechanism's effectiveness and potential application in mitigating endosomal entrapment are scrutinized. This paper provides a critical overview of the current landscape, emphasizing the need for advanced delivery systems to navigate the complexities of cellular uptake. Importantly, it underscores the transformative role of smart nanomaterials in revolutionizing cellular delivery strategies, leading to a paradigm shift towards improved therapeutic outcomes.

Unveiling Nanoparticles: Recent Approaches in Studying the Internalization Pattern of Iron Oxide Nanoparticles in Mono- and Multicellular Biological Structures

Nanoparticle (NP)-based solutions for oncotherapy promise an improved efficiency of the anticancer response, as well as higher comfort for the patient. The current advancements in cancer treatment based on nanotechnology exploit the ability of these systems to pass biological barriers to target the tumor cell, as well as tumor cell organelles. In particular, iron oxide NPs are being clinically employed in oncological management due to this ability. When designing an efficient anti-cancer therapy based on NPs, it is important to know and to modulate the phenomena which take place during the interaction of the NPs with the tumor cells, as well as the normal tissues. In this regard, our review is focused on highlighting different approaches to studying the internalization patterns of iron oxide NPs in simple and complex 2D and 3D in vitro cell models, as well as in living tissues, in order to investigate the functionality of an NP-based treatment.

Treating Alzheimer's disease using nanoparticle-mediated drug delivery strategies/systems

The administration of promising medications for the treatment of neurodegenerative disorders (NDDs), such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS) is significantly hampered by the blood-brain barrier (BBB). Nanotechnology has recently come to light as a viable strategy for overcoming this obstacle and improving drug delivery to the brain. With a focus on current developments and prospects, this review article examines the use of nanoparticles to overcome the BBB constraints to improve drug therapy for AD The potential for several nanoparticle-based approaches, such as those utilizing lipid-based, polymeric, and inorganic nanoparticles, to enhance drug transport across the BBB are highlighted. To shed insight on their involvement in aiding effective drug transport to the brain, methods of nanoparticle-mediated drug delivery, such as surface modifications, functionalization, and particular targeting ligands, are also investigated. The article also discusses the most recent findings on innovative medication formulations encapsulated within nanoparticles and the therapeutic effects they have shown in both preclinical and clinical testing. This sector has difficulties and restrictions, such as the need for increased safety, scalability, and translation to clinical applications. However, the major emphasis of this review aims to provide insight and contribute to the knowledge of how nanotechnology can potentially revolutionize the worldwide treatment of NDDs, particularly AD, to enhance clinical outcomes.

Characterization Methods for Nanoparticle-Skin Interactions: An Overview

Research progresses have led to the development of different kinds of nanoplatforms to deliver drugs through different biological membranes. Particularly, nanocarriers represent a precious means to treat skin pathologies, due to their capability to solubilize lipophilic and hydrophilic drugs, to control their release, and to promote their permeation through the stratum corneum barrier. A crucial point in the development of nano-delivery systems relies on their characterization, as well as in the assessment of their interaction with tissues, in order to predict their fate under in vivo administration. The size of nanoparticles, their shape, and the type of matrix can influence their biodistribution inside the skin strata and their cellular uptake. In this respect, an overview of some characterization methods employed to investigate nanoparticles intended for topical administration is presented here, namely dynamic light scattering, zeta potential, scanning and transmission electron microscopy, X-ray diffraction, atomic force microscopy, Fourier transform infrared and Raman spectroscopy. In addition, the main fluorescence methods employed to detect the in vitro nanoparticles interaction with skin cell lines, such as fluorescence-activated cell sorting or confocal imaging, are described, considering different examples of applications. Finally, recent studies on the techniques employed to determine the nanoparticle presence in the skin by ex vivo and in vivo models are reported.

Critical Review: Uptake and Translocation of Organic Nanodelivery Vehicles in Plants

Nanodelivery vehicles (NDVs) are engineered nanomaterials (ENMs) that, within the agricultural sector, have been investigated for their ability to improve uptake and translocation of agrochemicals, control release, or target specific tissues or subcellular compartments. Both inorganic and organic NDVs have been studied for agrochemical delivery in the literature, but research on the latter has been slower to develop than the literature on the former. Since the two classes of nanomaterials exhibit significant differences in surface chemistry, physical deformability, and even colloidal stability, trends that apply to inorganic NDVs may not hold for organic NDVs, and vice versa. We here review the current literature on the uptake, translocation, biotransformation, and cellular and subcellular internalization of organic NDVs in plants following foliar or root administration. A background on nanomaterials and plant physiology is provided as a leveling ground for researchers in the field. Trends in uptake and translocation are examined as a function of NDV properties and compared to those reported for inorganic nanomaterials. Methods for assessing fate and transport of organic NDVs in plants (a major bottleneck in the field) are discussed. We end by identifying knowledge gaps in the literature that must be understood in order to rationally design organic NDVs for precision agrochemical nanodelivery.

Unlocking the Mitochondria for Nanomedicine-based Treatments: Overcoming Biological Barriers, Improving Designs, and Selecting Verification Techniques

Enhanced targeting approaches will support the treatment of diseases associated with dysfunctional mitochondria, which play critical roles in energy generation and cell survival. Obstacles to mitochondria-specific targeting include the presence of distinct biological barriers and the need to pass through (or avoid) various cell internalization mechanisms. A range of studies have reported the design of mitochondrially-targeted nanomedicines that navigate the complex routes required to influence mitochondrial function; nonetheless, a significant journey lies ahead before mitochondrially-targeted nanomedicines become suitable for clinical use. Moving swiftly forward will require safety studies, in vivo assays confirming effectiveness, and methodologies to validate mitochondria-targeted nanomedicines' subcellular location/activity. From a nanomedicine standpoint, we describe the biological routes involved (from administration to arrival within the mitochondria), the features influencing rational design, and the techniques used to identify/validate successful targeting. Overall, rationally-designed mitochondria-targeted-based nanomedicines hold great promise for precise subcellular therapeutic delivery.

Bridging Smart Nanosystems with Clinically Relevant Models and Advanced Imaging for Precision Drug Delivery

Intracellular delivery of nano-drug-carriers (NDC) to specific cells, diseased regions, or solid tumors has entered the era of precision medicine that requires systematic knowledge of nano-biological interactions from multidisciplinary perspectives. To this end, this review first provides an overview of membrane-disruption methods such as electroporation, sonoporation, photoporation, microfluidic delivery, and microinjection with the merits of high-throughput and enhanced efficiency for in vitro NDC delivery. The impact of NDC characteristics including particle size, shape, charge, hydrophobicity, and elasticity on cellular uptake are elaborated and several types of NDC systems aiming for hierarchical targeting and delivery in vivo are reviewed. Emerging in vitro or ex vivo human/animal-derived pathophysiological models are further explored and highly recommended for use in NDC studies since they might mimic in vivo delivery features and fill the translational gaps from animals to humans. The exploration of modern microscopy techniques for precise nanoparticle (NP) tracking at the cellular, organ, and organismal levels informs the tailored development of NDCs for in vivo application and clinical translation. Overall, the review integrates the latest insights into smart nanosystem engineering, physiological models, imaging-based validation tools, all directed towards enhancing the precise and efficient intracellular delivery of NDCs.

Defining the EM-signature of successful cell-transfection

In this report, we describe the architecture of Lipofectamine 2000 and 3000 transfection- reagents, as they appear inside of transfected cells, using classical transmission electron microscopy (EM). We also demonstrate that they provoke consistent structural changes after they have entered cells, changes that not only provide new insights into the mechanism of action of these particular transfection-reagents, but also provide a convenient and robust method for identifying by EM which cells in any culture have been successfully transfected. This also provides clues to the mechanism(s) of their toxic effects, when they are applied in excess. We demonstrate that after being bulk-endocytosed by cells, the cationic spheroids of Lipofectamine remain intact throughout the entire time of culturing, but escape from their endosomes and penetrate directly into the cytoplasm of the cell. In so doing, they provoke a stereotypical recruitment and rearrangement of endoplasmic reticulum (ER), and they ultimately end up escaping into the cytoplasm and forming unique 'inclusion-bodies.' Once free in the cytoplasm, they also invariably develop dense and uniform coatings of cytoplasmic ribosomes on their surfaces, and finally, they become surrounded by 'annulate' lamellae' of the ER. In the end, these annulate-lamellar enclosures become the ultrastructural 'signatures' of these inclusion-bodies, and serve to positively and definitively identify all cells that have been effectively transfected. Importantly, these new EM-observations define several new and unique properties of these classical Lipofectamines, and allow them to be discriminated from other lipoidal or particulate transfection-reagents, which we find do not physically break out of endosomes or end up in inclusion bodies, and in fact, provoke absolutely none of these 'signature' cytoplasmic reactions.

Extracellular vesicles from adipose mesenchymal stem cells target inflamed lymph nodes in experimental autoimmune encephalomyelitis

BACKGROUND AIMS

Adipose mesenchymal stem cells (ASCs) represent a promising therapeutic approach in inflammatory neurological disorders, including multiple sclerosis (MS). Recent lines of evidence indicate that most biological activities of ASCs are mediated by the delivery of soluble factors enclosed in extracellular vesicles (EVs). Indeed, we have previously demonstrated that small EVs derived from ASCs (ASC-EVs) ameliorate experimental autoimmune encephalomyelitis (EAE), a murine model of MS. The precise mechanisms and molecular/cellular target of EVs during EAE are still unknown.

METHODS

To investigate the homing of ASC-EVs, we intravenously injected small EVs loaded with ultra-small superparamagnetic iron oxide nanoparticles (USPIO) at disease onset in EAE-induced C57Bl/6J mice. Histochemical analysis and transmission electron microscopy were carried out 48 h after EV treatment. Moreover, to assess the cellular target of EVs, flow cytometry on cells extracted ex vivo from EAE mouse lymph nodes was performed.

RESULTS

Histochemical and ultrastructural analysis showed the presence of labeled EVs in lymph nodes but not in lungs and spinal cord of EAE injected mice. Moreover, we identified the cellular target of EVs in EAE lymph nodes by flow cytometry: ASC-EVs were preferentially located in macrophages, with a consistent amount also noted in dendritic cells and CD4+ T lymphocytes.

CONCLUSIONS

This represents the first direct evidence of the privileged localization of ASC-EVs in draining lymph nodes of EAE after systemic injection. These data provide prominent information on the distribution, uptake and retention of ASC-EVs, which may help in the development of EV-based therapy in MS.

Visualizing the intracellular aggregation behavior of gold nanoclusters via structured illumination microscopy and scanning transmission electron microscopy

Given the growing concerns about nanotoxicity, numerous studies have focused on providing mechanistic insights into nanotoxicity by imaging the intracellular fate of nanoparticles. A suitable imaging strategy is necessary to uncover the intracellular behavior of nanoparticles. Although each conventional technique has its own limitations, scanning transmission electron microscopy (STEM) and three-dimensional structured illumination microscopy (3D-SIM) combine the advantages of chemical element mapping, ultrastructural analysis, and cell dynamic tracking. Gold nanoclusters (AuNCs), synthesized using 6-aza-2 thiothymine (ATT) and L-arginine (Arg) as reducing and protecting ligands, referred to as Arg@ATT-AuNCs, have been widely used in biological sensing and imaging, medicine, and catalyst yield. Based on their intrinsic fluorescence and high electron density, Arg@ATT-AuNCs were selected as a model. STEM imaging showed that both the single-particle and aggregated states of Arg@ATT-AuNCs were compartmentally distributed within a single cell. Real-time 3D-SIM imaging showed that the fluorescent Arg@ATT-AuNCs gradually aggregated after being located in the lysosomes of living cells, causing lysosomal damage. The aggregate formation of Arg@ATT-AuNCs was triggered by the low-pH medium, particularly in the lysosomal acidic environment. The proposed dual imaging strategy was verified using other types of AuNCs, which is valuable for studying nano-cell interactions and any associated cytotoxicity, and has the potential to be a useful approach for exploring the interaction of cells with various nanoparticles.

Focused ion beam-scanning electron microscopy provides novel insights of drug delivery phenomena

Scanning electron microscopy (SEM) has long been a standard tool for morphological analyses, providing sub micrometer resolution of pharmaceutical formulations. However, analysis of internal morphologies of such formulations can often be biased due to the introduction of artifacts that originate from sample preparation. A recent advancement in SEM, is the focused ion beam scanning electron microscopy (FIB-SEM). This technique uses a focused ion beam (FIB) to remove material with nanometer precision, to provide virtually sample-independent access to sub-surface structures. The FIB can be combined with SEM imaging capabilities within the same instrumentation. As a powerful analytical tool, electron microscopy and FIB-milling are performed sequentially to produce high-resolution 3D models of structural peculiarities of diverse drug delivery systems or their behavior in a biological environment, i.e. intracellular or -tissue distribution. This review paper briefly describes the technical background of the method, outlines a wide array of potential uses within the drug delivery field, and focuses on intracellular transport where high-resolution images are an essential tool for mechanistical insights.

From lab to ecosystem: Understanding the ecological footprints of engineered nanoparticles

Nanotechnology has attained significant attention from researchers in past decades due to its numerous advantages, such as biocompatibility, biodegradability, and improved stability over conventional drug delivery systems. The fabrication of engineered nanoparticles (ENPs), including carbon nanotubes (CNTs), fullerenes, metallic and metal oxide-based NPs, has been steadily increasing day due to their wide range of applications from household to industrial applications. Fabricated ENPs can release different materials into the environment during their fabrication process. The effect of such materials on the environment is the primary concern with due diligence on the safety and efficacy of prepared NPs. In addition, an understanding of chemistry, reactivity, fabrication process, and viable mechanism of NPs involved in the interaction with the environment is very important. To date, only a limited number of techniques are available to assess ENPs in the natural environment which makes it difficult to ascertain the impact of ENPs in natural settings. This review extensively examines the environmental effects of ENPs and briefly discusses useful tools for determining NP size, surface charge, surface area, and external appearance. In conclusion, the review highlights the potential risks associated with ENPs and suggests possible solutions.

Characterization of Drug Delivery Systems by Transmission Electron Microscopy

The contribution of electron microscopy, and here, in particular transmission electron microscopy (TEM), to the formulation and understanding of the biological action of drug delivery systems has led to a better insight into the design principles of drug delivery systems. TEM can be applied for particle characterization, for the visualization of the uptake and intracellular pathways of drug vehicles in cells and tissues and more recently can be also applied for the high-resolution investigation of drug-receptor interactions with near-atomic resolution. This chapter introduces basic techniques to optimize imaging quality of soft matter samples, highlights possibilities to study certain aspects of drug delivery applications, and finally provides a short introduction to high-resolution characterization possibilities which recently emerged.

Research-based Analytical Procedures to Evaluate Diabetic Biomarkers and Related Parameters: In Vitro and In Vivo Methods

BACKGROUND

The degenerative tendency of diabetes leads to micro- and macrovascular complications due to abnormal levels of biochemicals, particularly in patients with poor diabetic control. Diabetes is supposed to be treated by reducing blood glucose levels, scavenging free radicals, and maintaining other relevant parameters close to normal ranges. In preclinical studies, numerous in vivo trials on animals as well as in vitro tests are used to assess the antidiabetic and antioxidant effects of the test substances. Since a substance that performs poorly in vitro won't perform better in vivo, the outcomes of in vitro studies can be utilized as a direct indicator of in vivo activities.

OBJECTIVE

The objective of the present study is to provide research scholars with a comprehensive overview of laboratory methods and procedures for a few selected diabetic biomarkers and related parameters.

METHOD

The search was conducted on scientific database portals such as ScienceDirect, PubMed, Google Scholar, BASE, DOAJ, etc. Conclusion: The development of new biomarkers is greatly facilitated by modern technology such as cell culture research, lipidomics study, microRNA biomarkers, machine learning techniques, and improved electron microscopies. These biomarkers do, however, have some usage restrictions. There is a critical need to find more accurate and sensitive biomarkers. With a few modifications, these biomarkers can be used with or even replace conventional markers of diabetes.

The Advancement and Obstacles in Improving the Stability of Nanocarriers for Precision Drug Delivery in the Field of Nanomedicine

Nanocarriers have emerged as a promising class of nanoscale materials in the fields of drug delivery and biomedical applications. Their unique properties, such as high surface area- tovolume ratios and enhanced permeability and retention effects, enable targeted delivery of therapeutic agents to specific tissues or cells. However, the inherent instability of nanocarriers poses significant challenges to their successful application. This review highlights the importance of nanocarrier stability in biomedical applications and its impact on biocompatibility, targeted drug delivery, long shelf life, drug delivery performance, therapeutic efficacy, reduced side effects, prolonged circulation time, and targeted delivery. Enhancing nanocarrier stability requires careful design, engineering, and optimization of physical and chemical parameters. Various strategies and cutting-edge techniques employed to improve nanocarrier stability are explored, with a focus on their applications in drug delivery. By understanding the advances and challenges in nanocarrier stability, this review aims to contribute to the development and implementation of nanocarrier- based therapies in clinical settings, advancing the field of nanomedicine.

Exosomes in Cancer Progression and Therapy Resistance: Molecular Insights and Therapeutic Opportunities

The development of therapy resistance still represents a major hurdle in treating cancers, leading to impaired treatment success and increased patient morbidity. The establishment of minimally invasive liquid biopsies is a promising approach to improving the early diagnosis, as well as therapy monitoring, of solid tumors. Because of their manifold functions in the tumor microenvironment, tumor-associated small extracellular vesicles, referred to as exosomes, have become a subject of intense research. Besides their important roles in cancer progression, metastasis, and the immune response, it has been proposed that exosomes also contribute to the acquisition and transfer of therapy resistance, mainly by delivering functional proteins and RNAs, as well as facilitating the export of active drugs or functioning as extracellular decoys. Extensive research has focused on understanding the molecular mechanisms underlying the occurrence of resistance and translating these into strategies for early detection. With this review, we want to provide an overview of the current knowledge about the (patho-)biology of exosomes, as well as state-of-the-art methods of isolation and analysis. Furthermore, we highlight the role of exosomes in tumorigenesis and cancer treatment, where they can function as therapeutic agents, biomarkers, and/or targets. By focusing on their roles in therapy resistance, we will reveal new paths of exploiting exosomes for cancer diagnosis and treatment.

Preparation of Nanoemulsions with Low-Molecular-Weight Collagen Peptides from Sturgeon Fish Skin and Evaluation of Anti-Diabetic and Wound-Healing Effects in Mice

This study aims to isolate collagen peptides from waste sturgeon fish skin, and prepare nanoemulsions for studying their anti-diabetic and wound-healing effects in mice. Collagen peptides were extracted and purified by acetic acid with sonication, followed by two-stage hydrolysis with 0.1% pepsin and 5% flavourzyme, and ultrafiltration with 500 Da molecular weight (MW) cut-off dialysis membrane. Animal experiments were performed with collagen peptides obtained by pepsin hydrolysis (37 kDa) and pepsin plus flavourzyme hydrolysis (728 Da) as well as their nanoemulsions prepared at two different doses (100 and 300 mg/kg/day). The mean particle size of low-MW and low-dose nanoemulsion, low-MW and high-dose nanoemulsion, high-MW and low-dose nanoemulsion and high-MW and high-dose nanoemulsion was, respectively, 16.9, 15.3, 28.1 and 24.2 nm, the polydispersity index was 0.198, 0.215, 0.231 and 0.222 and zeta potential was -61.2, -63.0, -41.4 and -42.7 mV. These nanoemulsions were highly stable over a 90-day storage period (4 °C and 25 °C) and heating at 40-100 °C (0.5-2 h). Experiments in mice revealed that the low-MW and high-dose nanoemulsion was the most effective in decreasing fasting blood glucose (46.75%) and increasing wound-healing area (95.53%). Collectively, the sturgeon fish skin collagen peptide-based nanoemulsion is promising for development into a health food or wound-healing drug.

Ex vivo fluorescence imaging for the identification of rhodamine-labeled bovine serum albumin and chitosan-coated gold and silver nanoparticles

Therapeutic potential and toxic effects of in vivo administered gold nanoparticles (GNPs) and silver nanoparticles (SNP) depend on distribution in tissues. Rhodamine (Rho) labeled bovine serum albumin (BSA) and chitosan (Chi) were prepared by covalent conjugation and were characterized by fluorescence spectral analysis. GNP and SNP were coated with the labeled conjugates of BSA and chitosan by adsorption. The soluble Rho-BSA or Rho-Chi conjugates, uncoated, and conjugate-coated GNP, and SNP were orally administered into 8-week-old rats. After 24 h, rats were euthanized and the liver, kidney, spleen, and thymus were dissected. The tissues were examined ex vivo using a small animal in vivo imaging system. The liver, kidney, and thymus displayed higher fluorescence due to increased accumulation of Rho-BSA or Rho-Chi conjugate-coated nanoparticles (NPs) in the tissues as compared to the spleen where lower fluorescence was noticed. Tissues obtained from rats that were administered Rho-BSA or Rho-Chi conjugate-coated GNP and SNP showed tenfold higher fluorescence intensity as compared to tissues from rats that were given soluble conjugates or NP alone. The results strongly suggest significant tissue distribution of NP following oral administration.

Kinetic Effects of Transferrin-Conjugated Gold Nanoparticles on the Antioxidant Glutathione-Thioredoxin Pathway

Nanoparticle-based therapeutics are being clinically translated for treating cancer. Even when thought to be biocompatible, nanoparticles are being increasingly identified as altering cell regulation and homeostasis. Antioxidant pathways are important for maintaining cell redox homeostasis and play important roles by maintaining ROS levels within tolerable ranges. Here, we sought to understand how a model of a relatively inert nanoparticle without any therapeutic agent itself could antagonize a cancer cell lines' antioxidant mechanism. A label-free protein expression approach was used to assess the glutathione-thioredoxin antioxidative pathway in a prostate cancer cell line (PC-3) after exposure to gold nanoparticles conjugated with a targeting moiety (transferrin). The impact of the nanoparticles was also corroborated through morphological analysis with TEM and classification of pro-apoptotic cells by way of the sub-G0/G1 population via the cell cycle and annexin V apoptosis assay. After a two-hour exposure to nanoparticles, major proteins associated with the glutathione-thioredoxin antioxidant pathway were downregulated. However, this response was acute, and in terms of protein expression, cells quickly recovered within 24 h once nanoparticle exposure ceased. The impact on PRDX-family proteins appears as the most influential factor in how these nanoparticles induced an oxidative stress response in the PC-3 cells. An apparent adaptive response was observed if exposure to nanoparticles continued. Acute exposure was observed to have a detrimental effect on cell viability compared to continuously exposed cells. Nanoparticle effects on cell regulation likely provide a compounding therapeutic advantage under some circumstances, in addition to the action of any cytotoxic agents; however, any therapeutic advantage offered by nanoparticles themselves with regard to vulnerabilities specific to the glutathione-thioredoxin antioxidative pathway is highly temporal.

Deep Learning-Based TEM Image Analysis for Fully Automated Detection of Gold Nanoparticles Internalized Within Tumor Cell

Transmission electron microscopy (TEM) imaging can be used for detection/localization of gold nanoparticles (GNPs) within tumor cells. However, quantitative analysis of GNP-containing cellular TEM images typically relies on conventional/thresholding-based methods, which are manual, time-consuming, and prone to human errors. In this study, therefore, deep learning (DL)-based methods were developed for fully automated detection of GNPs from cellular TEM images. Several models of "you only look once (YOLO)" v5 were implemented, with a few adjustments to enhance the model's performance by applying the transfer learning approach, adjusting the size of the input image, and choosing the best optimization algorithm. Seventy-eight original (12,040 augmented) TEM images of GNP-laden tumor cells were used for model implementation and validation. A maximum F1 score (harmonic mean of the precision and recall) of 0.982 was achieved by the best-trained models, while mean average precision was 0.989 and 0.843 at 0.50 and 0.50-0.95 intersection over union threshold, respectively. These results suggested the developed DL-based approach was capable of precisely estimating the number/position of internalized GNPs from cellular TEM images. A novel DL-based TEM image analysis tool from this study will benefit research/development efforts on GNP-based cancer therapeutics, for example, by enabling the modeling of GNP-laden tumor cells using nanometer-resolution TEM images.

Factors affecting the preparation of nanocrystals: characterization, surface modifications and toxicity aspects

INTRODUCTION

The fabrication of well-defined nanocrystals in size and form is the focus of much investigation. In this work, we have critically reviewed several recent instances from the literature that shows how the production procedure affects the physicochemical properties of the nanocrystals.

AREAS COVERED

Scopus, MedLine, PubMed, Web of Science, and Google Scholar were searched for peer-review articles published in the past few years using different key words. Authors chose relevant publications from their files for this review. This review focuses on the range of techniques available for producing nanocrystals. We draw attention to several recent instances demonstrating the impact of various process and formulation variables that affect the nanocrystals' physicochemical properties. Moreover, various developments in the characterization techniques explored for nanocrystals concerning their size, morphology, etc. have been discussed. Last but not least, recent applications, the effect of surface modifications, and the toxicological traits of nanocrystals have also been reviewed.

EXPERT OPINION

The selection of an appropriate production method for the formation of nanocrystals, together with a deep understanding of the relationship between the drug's physicochemical properties, unique features of the various formulation alternatives, and anticipated in-vivo performance, would significantly reduce the risk of failure during human clinical trials that are inadequate.

Pre-Implantation Bovine Embryo Evaluation-From Optics to Omics and Beyond

Approximately 80% of the ~1.5 million bovine embryos transferred in 2021 were in vitro produced. However, only ~27% of the transferred IVP embryos will result in live births. The ~73% pregnancy failures are partly due to transferring poor-quality embryos, a result of erroneous stereomicroscopy-based morphological evaluation, the current method of choice for pre-transfer embryo evaluation. Numerous microscopic (e.g., differential interference contrast, electron, fluorescent, time-lapse, and artificial-intelligence-based microscopy) and non-microscopic (e.g., genomics, transcriptomics, epigenomics, proteomics, metabolomics, and nuclear magnetic resonance) methodologies have been tested to find an embryo evaluation technique that is superior to morphologic evaluation. Many of these research tools can accurately determine embryo quality/viability; however, most are invasive, expensive, laborious, technically sophisticated, and/or time-consuming, making them futile in the context of in-field embryo evaluation. However accurate they may be, using complex methods, such as RNA sequencing, SNP chips, mass spectrometry, and multiphoton microscopy, at thousands of embryo production/collection facilities is impractical. Therefore, future research is warranted to innovate field-friendly, simple benchtop tests using findings already available, particularly from omics-based research methodologies. Time-lapse monitoring and artificial-intelligence-based automated image analysis also have the potential for accurate embryo evaluation; however, further research is warranted to innovate economically feasible options for in-field applications.

Method for nanoparticles uptake evaluation based on double labeled fluorescent cells scanned in enhanced darkfield microscopy

We present a method that integrates the standard imaging tools for locating and detecting unlabeled nanoparticles (NPs) with computational tools for partitioning cell volumes and NPs counting within specified regions to evaluate their internal traffic. The method uses enhanced dark field CytoViva optical system and combines 3D reconstructions of double fluorescently labeled cells with hyperspectral images. The method allows the partitioning of each cell image into four regions: nucleus, cytoplasm, and two neighboring shells, as well as investigations across thin layers adjacent to the plasma membrane. MATLAB scripts were developed to process the images and to localize NPs in each region. Specific parameters were computed to assess the uptake efficiency: regional densities of NPs, flow densities, relative accumulation indices, and uptake ratios. The results of the method are in line with biochemical analyses. It was shown that a sort of saturation limit for intracellular NPs density is reached at high extracellular NPs concentrations. Higher NPs densities were found in the proximity of the plasma membranes. A decrease of the cell viability with increasing extracellular NPs concentration was observed and explained the negative correlation of the cell eccentricity with NPs number.

Quantifying Intracellular Nanoparticle Distributions with Three-Dimensional Super-Resolution Microscopy

Super-resolution microscopy can transform our understanding of nanoparticle-cell interactions. Here, we established a super-resolution imaging technology to visualize nanoparticle distributions inside mammalian cells. The cells were exposed to metallic nanoparticles and then embedded within different swellable hydrogels to enable quantitative three-dimensional (3D) imaging approaching electron-microscopy-like resolution using a standard light microscope. By exploiting the nanoparticles' light scattering properties, we demonstrated quantitative label-free imaging of intracellular nanoparticles with ultrastructural context. We confirmed the compatibility of two expansion microscopy protocols, protein retention and pan-expansion microscopy, with nanoparticle uptake studies. We validated relative differences between nanoparticle cellular accumulation for various surface modifications using mass spectrometry and determined the intracellular nanoparticle spatial distribution in 3D for entire single cells. This super-resolution imaging platform technology may be broadly used to understand the nanoparticle intracellular fate in fundamental and applied studies to potentially inform the engineering of safer and more effective nanomedicines.

Neonatal Pharmacokinetics and Biodistribution of Polymeric Nanoparticles and Effect of Surfactant

The development of therapeutics for pediatric use has advanced in the last few decades, yet the off-label use of adult medications in pediatrics remains a significant clinical problem. Nano-based medicines are important drug delivery systems that can improve the bioavailability of a range of therapeutics. However, the use of nano-based medicines for application in pediatric populations is challenged by the lack of pharmacokinetic (PK) data in this population. To address this data gap, we investigated the PK of polymer-based nanoparticles in term-equivalent neonatal rats. We used poly(lactic-co-glycolic acid)-poly(ethylene glycol) (PLGA-PEG) nanoparticles, which are polymer nanoparticles that have been extensively studied in adult populations but less commonly applied in neonates and pediatrics. We quantified the PK parameters and biodistribution of PLGA-PEG nanoparticles in term-equivalent healthy rats and revealed the PK and biodistribution of polymeric nanoparticles in neonatal rats. We further explored the effects of surfactant used to stabilize PLGA-PEG particles on PK and biodistribution. We showed that 4 h post intraperitoneal injection, nanoparticles had the highest accumulation in serum, at 54.0% of the injected dose for particles with Pluronic® F127 (F127) as the stabilizer and at 54.6% of the injected dose for particles with Poloxamer 188 (P80) as the stabilizer. The half-life of the F127-formulated PLGA-PEG particles was 5.9 h, which was significantly longer than the 1.7 h half-life of P80-formulated PLGA-PEG particles. Among all organs, the liver had the highest nanoparticle accumulation. At 24 h after administration, the accumulation of F127-formulated PLGA-PEG particles was at 26.2% of the injected dose, and the accumulation of P80-formulated particles was at 24.1% of the injected dose. Less than 1% of the injected nanoparticles was observed in healthy rat brain for both F127- and P80-formulated particles. These PK data inform the use of polymer nanoparticle applications in the neonate and provide a foundation for the translation of polymer nanoparticles for drug delivery in pediatric populations.

Light-Induced Clusterization of Gold Nanoparticles: A New Photo-Triggered Antibacterial against E. coli Proliferation

Metallic nanoparticles show plasmon resonance phenomena when irradiated with electromagnetic radiation of a suitable wavelength, whose value depends on their composition, size, and shape. The damping of the surface electron oscillation causes a release of heat, which causes a large increase in local temperature. Furthermore, this increase is enhanced when nanoparticle aggregation phenomena occur. Local temperature increase is extensively exploited in photothermal therapy, where light is used to induce cellular damage. To activate the plasmon in the visible range, we synthesized 50 nm diameter spherical gold nanoparticles (AuNP) coated with polyethylene glycol and administered them to an E. coli culture. The experiments were carried out, at different gold nanoparticle concentrations, in the dark and under irradiation. In both cases, the nanoparticles penetrated the bacterial wall, but a different toxic effect was observed; while in the dark we observed an inhibition of bacterial growth of 46%, at the same concentration, under irradiation, we observed a bactericidal effect (99% growth inhibition). Photothermal measurements and SEM observations allowed us to conclude that the extraordinary effect is due to the formation, at low concentrations, of a light-induced cluster of gold nanoparticles, which does not form in the absence of bacteria, leading us to the conclusion that the bacterium wall catalyzes the formation of these clusters which are ultimately responsible for the significant increase in the measured temperature and cause of the bactericidal effect. This photothermal effect is achieved by low-power irradiation and only in the presence of the pathogen: in its absence, the lack of gold nanoparticles clustering does not lead to any phototoxic effect. Therefore, it may represent a proof of concept of an innovative nanoscale pathogen responsive system against bacterial infections.

Membrane Integrity Assay in Ferroptosis

Ferroptosis is a form of regulated cell death that relies on the accumulation of intracellular iron and subsequent oxidative stress. Ferroptotic cell death is characterized by uncontrolled lipid peroxidation, which leads to plasma membrane damage and rupture. The loss of plasma membrane integrity results in the release of intracellular components, including damage-associated molecular patterns, and can propagate death between cells in a synchronized manner. Understanding the mechanisms of ferroptotic membrane damage is crucial to comprehending this form of cell death. This chapter provides a summary of techniques for detecting plasma membrane integrity in ferroptosis, including transmission electron microscopy analysis, flow cytometry analysis, and assessments of oxidoreductase-mediated membrane damage.

A Review on Low-Dimensional Nanomaterials: Nanofabrication, Characterization and Applications

The development of modern cutting-edge technology relies heavily on the huge success and advancement of nanotechnology, in which nanomaterials and nanostructures provide the indispensable material cornerstone. Owing to their nanoscale dimensions with possible quantum limit, nanomaterials and nanostructures possess a high surface-to-volume ratio, rich surface/interface effects, and distinct physical and chemical properties compared with their bulk counterparts, leading to the remarkably expanded horizons of their applications. Depending on their degree of spatial quantization, low-dimensional nanomaterials are generally categorized into nanoparticles (0D); nanorods, nanowires, and nanobelts (1D); and atomically thin layered materials (2D). This review article provides a comprehensive guide to low-dimensional nanomaterials and nanostructures. It begins with the classification of nanomaterials, followed by an inclusive account of nanofabrication and characterization. Both top-down and bottom-up fabrication approaches are discussed in detail. Next, various significant applications of low-dimensional nanomaterials are discussed, such as photonics, sensors, catalysis, energy storage, diverse coatings, and various bioapplications. This article would serve as a quick and facile guide for scientists and engineers working in the field of nanotechnology and nanomaterials.

Ex Vivo Evaluation of Ethosomes and Transethosomes Applied on Human Skin: A Comparative Study

In this study, the transdermal fate of vesicular nanosystems was investigated. Particularly, ethosomes based on phosphatidylcholine 0.9% w/w and transethosomes based on phosphatidylcholine 0.9 or 2.7% w/w plus polysorbate 80 0.3% w/w as an edge activator were prepared and characterized. The vesicle mean size, morphology and deformability were influenced by both phosphatidylcholine and polysorbate 80. Indeed, the mean diameters of ethosome were around 200 nm, while transethosome's mean diameters were 146 or 350 nm in the case of phosphatidylcholine 0.9 or 2.7%, w/w, respectively. The highest deformability was achieved by transethosomes based on phosphatidylcholine 0.9%, w/w. The three types of vesicular nanosystems were applied on explanted human skin maintained in a bioreactor. Transmission electron microscopy demonstrated that all vesicles were able to enter the skin, keeping their structural integrity. Notably, the vesicle penetration capability was influenced by their physical-chemical features. Indeed, ethosomes reached keratinocytes and even the dermis, phosphatidylcholine 0.9% transethosomes were found in keratinocytes and phosphatidylcholine 2.7% transethosomes were found only in corneocytes of the outer layer. These findings open interesting perspectives for a differentiated application of these vesicles for transdermal drug delivery as a function of the cutaneous pathology to be addressed.

Hemolytic Activity of Nanoparticles as a Marker of Their Hemocompatibility

The potential use of nanomaterials in medicine offers opportunities for novel therapeutic approaches to treating complex disorders. For that reason, a new branch of science, named nanotoxicology, which aims to study the dangerous effects of nanomaterials on human health and on the environment, has recently emerged. However, the toxicity and risk associated with nanomaterials are unclear or not completely understood. The development of an adequate experimental strategy for assessing the toxicity of nanomaterials may include a rapid/express method that will reliably, quickly, and cheaply make an initial assessment. One possibility is the characterization of the hemocompatibility of nanomaterials, which includes their hemolytic activity as a marker. In this review, we consider various factors affecting the hemolytic activity of nanomaterials and draw the reader's attention to the fact that the formation of a protein corona around a nanoparticle can significantly change its interaction with the red cell. This leads us to suggest that the nanomaterial hemolytic activity in the buffer does not reflect the situation in the blood plasma. As a recommendation, we propose studying the hemocompatibility of nanomaterials under more physiologically relevant conditions, in the presence of plasma proteins in the medium and under mechanical stress.

Assessing the interactions between nanoparticles and biological barriers in vitro: a new challenge for microscopy techniques in nanomedicine

Nanoconstructs intended to be used as biomedical tool must be assessed for their capability to cross biological barriers. However, studying in vivo the permeability of biological barriers to nanoparticles is quite difficult due to the many structural and functional factors involved. Therefore, the in vitro modeling of biological barriers -2D cell monocultures, 2D/3D cell co-cultures, microfluidic devices- is gaining more and more relevance in nanomedical research. Microscopy techniques play a crucial role in these studies, as they allow both visualizing nanoparticles inside the biological barrier and evaluating their impact on the barrier components. This paper provides an overview of the various microscopical approaches used to investigate nanoparticle translocation through in vitro biological barrier models. The high number of scientific articles reported highlights the great contribution of the morphological and histochemical approach to the knowledge of the dynamic interactions between nanoconstructs and the living environment.

Carbonaceous Nanoparticle Air Pollution: Toxicity and Detection in Biological Samples

Among the different air pollutants, particulate matter (PM) is of great concern due to its abundant presence in the atmosphere, which results in adverse effects on the environment and human health. The different components of PM can be classified based on their physicochemical properties. Carbonaceous particles (CPs) constitute a major fraction of ultrafine PM and have the most harmful effects. Herein, we present a detailed overview of the main components of CPs, e.g., carbon black (CB), black carbon (BC), and brown carbon (BrC), from natural and anthropogenic sources. The emission sources and the adverse effects of CPs on the environment and human health are discussed. Particularly, we provide a detailed overview of the reported toxic effects of CPs in the human body, such as respiratory effects, cardiovascular effects, neurodegenerative effects, carcinogenic effects, etc. In addition, we also discuss the challenges faced by and limitations of the available analytical techniques for the qualitative and quantitative detection of CPs in atmospheric and biological samples. Considering the heterogeneous nature of CPs and biological samples, a detailed overview of different analytical techniques for the detection of CPs in (real-exposure) biological samples is also provided. This review provides useful insights into the classification, toxicity, and detection of CPs in biological samples.

Biogenic Silver Nanoparticles from Two Varieties of Agaricus bisporus and Their Antibacterial Activity

Agaricus bisporus, the most widely cultivated mushroom, is safe to eat and enriched with protein and secondary metabolites. We prepared silver nanoparticles (AgNPs) from two varieties of A. bisporus and tested their antibacterial activity The synthesized AgNPs were initially confirmed by UV-Vis spectroscopy peaks at 420 and 430 nm for white and brown mushrooms AgNPs, respectively. AgNPs were further characterized by zeta sizer, transmission electronic microscopy (TEM), Fourier transform infrared (FTIR), and energy-dispersive X-ray spectroscopy (EDX) prior to antibacterial activity by the well diffusion method against six bacterial strains which include Staphylococcus aureus, Staphylococcus epidermis, Bacillus subtilis, Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa. TEM results revealed a spherical shape with an average diameter of about 11 nm in the white mushroom extract and 5 nm in the brown mushroom extract. The presence of elemental silver in the prepared AgNPs was confirmed by EDS. The IR spectrum of the extract confirmed the presence of phenols, flavonoids, carboxylic, or amide groups which aided in the reduction and capping of synthesized AgNPs. The AgNPs from both extracts showed almost the same results; however, nanoparticles prepared from brown mushrooms were smaller in size with strong antibacterial activity.

Molecular Imaging in Nanomedical Research 2.0

Over the last two decades, imaging techniques have become irreplaceable tools in nanotechnology: electron microscopy techniques are routinely used to observe the structural features of newly manufactured nanoconstructs, while light and electron microscopy, magnetic resonance imaging, optical imaging, positron emission tomography, and ultrasound imaging allow dynamic monitoring of the biodistribution, targeting and clearance of nanoparticulates in living systems, either for the whole organism or at the level of single cells, tissues and organs [...]

In Vitro Models of Biological Barriers for Nanomedical Research

Nanoconstructs developed for biomedical purposes must overcome diverse biological barriers before reaching the target where playing their therapeutic or diagnostic function. In vivo models are very complex and unsuitable to distinguish the roles plaid by the multiple biological barriers on nanoparticle biodistribution and effect; in addition, they are costly, time-consuming and subject to strict ethical regulation. For these reasons, simplified in vitro models are preferred, at least for the earlier phases of the nanoconstruct development. Many in vitro models have therefore been set up. Each model has its own pros and cons: conventional 2D cell cultures are simple and cost-effective, but the information remains limited to single cells; cell monolayers allow the formation of cell–cell junctions and the assessment of nanoparticle translocation across structured barriers but they lack three-dimensionality; 3D cell culture systems are more appropriate to test in vitro nanoparticle biodistribution but they are static; finally, bioreactors and microfluidic devices can mimicking the physiological flow occurring in vivo thus providing in vitro biological barrier models suitable to reliably assess nanoparticles relocation. In this evolving context, the present review provides an overview of the most representative and performing in vitro models of biological barriers set up for nanomedical research.

Physiology and Transcriptomics Analysis Reveal the Contribution of Lungs on High-Altitude Hypoxia Adaptation in Tibetan Sheep

The Tibetan sheep is an indigenous species on the Tibetan plateau with excellent adaptability to high-altitude hypoxia and is distributed at altitudes of 2500–5000 m. The high-altitude hypoxia adaptation of Tibetan sheep requires adaptive reshaping of multiple tissues and organs, especially the lungs. To reveal the mechanisms of adaptation at the tissue and molecular levels in the lungs of Tibetan sheep under hypoxic conditions at different altitudes, we performed light and electron microscopic observations, transcriptomic sequencing, and enzyme-linked immunosorbent assay studies on the lungs of Tibetan sheep from three altitudes (2500, 3500, and 4500 m). The results showed that in addition to continuous increase in pulmonary artery volume, thickness, and elastic fiber content with altitude, Tibetan sheep increase the hemoglobin concentration at an altitude of 3500 m, while they decrease the Hb concentration and increase the surface area of gas exchange and capacity of the blood at an altitude of 4500 m. Other than that, some important differentially expressed genes related to angiogenesis (FNDC1, HPSE, and E2F8), vasomotion and fibrogenesis (GJA4, FAP, COL1A1, COL1A2, COL3A1, and COL14A1), and gas transport (HBB, HBA1, APOLD1, and CHL1) were also identified; these discoveries at the molecular level explain to some extent the physiological findings. In conclusion, the lungs of Tibetan sheep adopt different strategies when adapting to different altitudes, and these findings are valuable for understanding the basis of survival of indigenous species on the Tibetan plateau.

Histochemistry for nanomedicine: Novelty in tradition

During the last two centuries, histochemistry has provided significant advancements in many fields of life sciences. After a period of neglect due to the great development of biomolecular techniques, the histochemical approach has been reappraised and is now widely applied in the field of nanomedicine. In fact, the novel nanoconstructs intended for biomedical purposes must be visualized to test their interaction with tissue and cell components. To this aim, several long-established staining methods have been re-discovered and re-interpreted in an unconventional way for unequivocal identification of nanoparticulates at both light and transmission electron microscopy.