Size-Dependent Transport and Cytotoxicity of Mitomycin-Gold Nanoparticle Conjugates in 2D and 3D Mammalian Cell Models

Size-Related Pathway Flux Analysis of Ultrasmall Iron Oxide Nanoparticles in Macrophage Cell RAW264.7 for Safety Evaluation

The endocytosis, intracellular transport, and exocytosis of different-sized nanoparticles were reported to greatly affect their efficacy and biosafety. The quantitation of endocytosis and exocytosis as well as subcellular distribution of nanoparticles might be an effective approach based on transport pathway flux analysis. Thus, the key parameters that could present the effects of three different-sized ultrasmall iron oxide nanoparticles (USIONPs) were systematically investigated in RAW264.7 cells. The endocytosis and exocytosis of USIONPs were related to their sizes; 15.4 nm of S2 could be quickly and more internalized and excreted in comparison to S1 (7.8 nm) and S3 (30.7 nm). In RAW264.7 cells, USIONPs were observed in endosomes, lysosomes, the Golgi apparatus, and autophagosomes via a transmission electron microscope. Based on flux analysis of intracellular transport pathways of USIONPs, it was found that 43% of S1, 40% of S2, and 44% of S3 were individually transported extracellularly through the Golgi apparatus-involved middle-fast pathway, while 24% of S1, 23% of S2, and 26% of S3 were transported through the fast recycling endosomal pathway, and the residues were transported through the slower speed lysosomal pathway. USIONPs might be transported via size-related endocytosis and exocytosis pathways. The pathway flux could be calculated on the basis of disturbance analysis of special transporters as well as their coding genes. Because there were rate differences among these transport pathways, this pathway flux could anticipate the intracellular remaining time and distribution of different-sized nanoparticles, the function exertion, and side effects of nanomaterials. The size of the nanomaterials could be optimized for improving functions and safety.

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

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

Mechanisms of Nanoparticle Transport across Intestinal Tissue: An Oral Delivery Perspective

Oral drug administration has been a popular choice due to patient compliance and limited clinical resources. Orally delivered drugs must circumvent the harsh gastrointestinal (GI) environment to effectively enter the systemic circulation. The GI tract has a number of structural and physiological barriers that limit drug bioavailability including mucus, the tightly regulated epithelial layer, immune cells, and associated vasculature. Nanoparticles have been used to enhance oral bioavailability of drugs, as they can act as a shield to the harsh GI environment and prevent early degradation while also increasing uptake and transport of drugs across the intestinal epithelium. Evidence suggests that different nanoparticle formulations may be transported via different intracellular mechanisms to cross the intestinal epithelium. Despite the existence of a significant body of work on intestinal transport of nanoparticles, many key questions remain: What causes the poor bioavailability of the oral drugs? What factors contribute to the ability of a nanoparticle to cross different intestinal barriers? Do nanoparticle properties such as size and charge influence the type of endocytic pathways taken? In this Review, we summarize the different components of intestinal barriers and the types of nanoparticles developed for oral delivery. In particular, we focus on the various intracellular pathways used in nanoparticle internalization and nanoparticle or cargo translocation across the epithelium. Understanding the gut barrier, nanoparticle characteristics, and transport pathways may lead to the development of more therapeutically useful nanoparticles as drug carriers.

Local Drug Delivery Strategies towards Wound Healing

A particular biological process known as wound healing is connected to the overall phenomena of growth and tissue regeneration. Several cellular and matrix elements work together to restore the integrity of injured tissue. The goal of the present review paper focused on the physiology of wound healing, medications used to treat wound healing, and local drug delivery systems for possible skin wound therapy. The capacity of the skin to heal a wound is the result of a highly intricate process that involves several different processes, such as vascular response, blood coagulation, fibrin network creation, re-epithelialisation, collagen maturation, and connective tissue remodelling. Wound healing may be controlled with topical antiseptics, topical antibiotics, herbal remedies, and cellular initiators. In order to effectively eradicate infections and shorten the healing process, contemporary antimicrobial treatments that include antibiotics or antiseptics must be investigated. A variety of delivery systems were described, including innovative delivery systems, hydrogels, microspheres, gold and silver nanoparticles, vesicles, emulsifying systems, nanofibres, artificial dressings, three-dimensional printed skin replacements, dendrimers and carbon nanotubes. It may be inferred that enhanced local delivery methods might be used to provide wound healing agents for faster healing of skin wounds.

Multiparametric nanoparticle-induced toxicity readouts with single cell resolution in HepG2 multicellular tumour spheroids

The use of nanomaterials as therapeutic delivery vehicles requires their careful pre-clinical evaluation. Of particular importance in this regard is measurement of cellular toxicity, ideally assessing multiple parameters in parallel from various relevant subcellular organelles. In recent years it has become evident that in vitro monolayer-grown cells do not always accurately predict any toxicity response seen in vivo, and so there is a need for more sophisticated in vitro cell models, employing a greater depth of characterisation. In this work we present an automated high-content screening microscopy approach for quantifying nanoparticle-induced toxicity in a three-dimensional multicellular tumour spheroid (MCTS) cell model. As a proof-of-principle, we perform a comparative toxicity profile study of carboxylate- versus amine-modified polystyrene nanoparticles in HepG2 spheroids. Following treatment with these nanoparticle types, we demonstrate that several hundred spheroids, of various sizes, can be morphologically profiled in a single well using automated high-content image analysis. This provides a first level of information about spheroid health in response to nanoparticle treatment. Using a range of fluorescent reporters assessing membrane permeability, lysosome function and mitochondrial activity, we also show that nanoparticle-induced toxicity information can be obtained from individual cells with subcellular resolution. Strikingly, our work demonstrates that individual cells do not all behave in a consistent manner within a spheroid structure after exposure to nanoparticles. This highlights the need for toxicity studies to not only assess an appropriate number of spheroids, but also the importance of extracting information at the subcellular level.

Understanding the interactions between inorganic-based nanomaterials and biological membranes

The interactions between inorganic-based nanomaterials (NMs) and biological membranes are among the most important phenomena for developing NM-based therapeutics and resolving nanotoxicology. Herein, we introduce the structural and functional effects of inorganic-based NMs on biological membranes, mainly the plasma membrane and the endomembrane system, with an emphasis on the interface, which involves highly complex networks between NMs and biomolecules (such as membrane proteins and lipids). Significant efforts have been devoted to categorizing and analyzing the interaction mechanisms in terms of the physicochemical characteristics and biological effects of NMs, which can directly or indirectly influence the effects of NMs on membranes. Importantly, we summarize that the biological membranes act as platforms and thereby mediate NMs-immune system contacts. In this overview, the existing challenges and potential applications in the areas are addressed. A strong understanding of the discussed concepts will promote therapeutic NM designs for drug delivery systems by leveraging the NMs-membrane interactions and their functions.

3D Tumor Spheroid Models for In Vitro Therapeutic Screening of Nanoparticles

The anticancer activity of compounds and nanoparticles is most often determined in the cell monolayer. However, three-dimensional (3D) systems, such as tumor spheroids, are more representing the natural tumor microenvironment. They have been shown to have higher invasiveness and resistance to cytotoxic agents and radiotherapy compared to cells growing in 2D monolayer. Furthermore, to improve the prediction of clinical efficacy of drugs, in the past decades, even more sophisticated systems, such as multicellular 3D cultures, closely representing natural tumor microenvironment have been developed. Those cultures are formed from either cell lines or patient-derived tumor cells. Such models are very attractive and could improve the selection of tested materials for clinical trials avoiding unnecessary expensive tests in vivo. The microenvironment in tumor spheroids is different, and those differences or the interaction between several cell populations may contribute to different tumor response to the treatment. Also, different types of nanoparticles may have different behavior in 3D models, depending on their nature, physicochemical properties, the presence of targeting ligands on the surface, etc. Therefore, it is very important to understand in which cases which type of tumor spheroid is more suitable for testing specific types of nanoparticles, which conditions should be used, and which analytical method should be applied.

Mechanistic Approaches of Internalization, Subcellular Trafficking, and Cytotoxicity of Nanoparticles for Targeting the Small Intestine

Targeting the small intestine employing nanotechnology has proved to be a more effective way for site-specific drug delivery. The drug targeting to the small intestine can be achieved via nanoparticles for its optimum bioavailability within the systemic circulation. The small intestine is a remarkable candidate for localized drug delivery. The intestine has its unique properties. It has a less harsh environment than the stomach, provides comparatively more retention time, and possesses a greater surface area than other parts of the gastrointestinal tract. This review focuses on elaborating the intestinal barriers and approaches to overcome these barriers for internalizing nanoparticles and adopting different cellular trafficking pathways. We have discussed various factors that contribute to nanocarriers' cellular uptake, including their surface chemistry, surface morphology, and functionalization of nanoparticles. Furthermore, the fate of nanoparticles after their uptake at cellular and subcellular levels is also briefly explained. Finally, we have delineated the strategies that are adopted to determine the cytotoxicity of nanoparticles.

NIR II-Excited and pH-Responsive Ultrasmall Nanoplatform for Deep Optical Tissue and Drug Delivery Penetration and Effective Cancer Chemophototherapy

The limited tumor tissue penetration of many nanoparticles remains a formidable challenge to their therapeutic efficacy. Although several photonanomedicines have been applied to improve tumor penetration, the first near-infrared window mediated by the low optical tissue penetration depth severely limits their anticancer effectiveness. To achieve deep optical tissue and drug delivery penetration, a near-infrared second window (NIR-II)-excited and pH-responsive ultrasmall drug delivery nanoplatform was fabricated based on BSA-stabilized CuS nanoparticles (BSA@CuS NPs). The BSA@CuS NPs effectively encapsulated doxorubicin (DOX) via strong electrostatic interactions to form multifunctional nanoparticles (BSA@CuS@DOX NPs). The BSA@CuS@DOX NPs had an ultrasmall size, which allowed them to achieve deeper tumor penetration. They also displayed stronger NIR II absorbance-mediated deep optical tissue penetration than that of the NIR I window. Moreover, the multifunctional nanoplatform preferentially accumulated in tumor sites, induced tumor hyperthermia, and generated remarkably high ROS levels in tumor sites upon NIR-II laser (1064 nm) irradiation. More importantly, our strategy achieved excellent synergistic effects of chemotherapy and phototherapy (chemophototherapy) under the guidance of photothermal imaging. The developed nanoparticles also showed good biocompatibility and bioclearance properties. Therefore, our work demonstrated a facile strategy for fabricating a multifunctional nanoplatform that is a promising candidate for deep tumor penetration as an effective antitumor therapy.

Viability evaluation of layered cell sheets after ultraviolet light irradiation of 222 nm

Introduction

The objective of this study was to evaluate the cell viability of layered cell sheets, irradiated with 222 nm UV light.

Methods

UV transmittance of 222 nm and 254 nm was evaluated when the cell sheets of NCTC Clone 929 cells were irradiated UV light. Cell viability was evaluated after irradiation of 222 nm using 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide (MTT) assay. Following irradiation of two layered cell sheets at 500 mJ/cm², the cell damage of lower layers was evaluated by a colony formation and MTT assays.

Results

The UV transmittance of 222 nm was 10 times less than that of 254 nm. A MTT assay revealed that cells of cell sheets irradiated at 222 nm was less damaged than those at 254 nm, when irradiated at 5 mJ/cm². Cell colonies were formed for cells of lower layers irradiated at 222 nm whereas no colony formation was observed for those irradiated at 254 nm. Significantly higher MTT activity was observed for cells of lower layers irradiated at 222 nm than at 254 nm.

Conclusions

It is concluded that 222 nm irradiation is biologically safe for cell viability.

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The cell viability of two-layered cell sheets was evaluated after irradiation of UV light at 222 nm.

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UV light at 222 nm is safer to the lower layer than the conventional UV light at 254 nm.

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The reason can be attributed to the lower transmission of UV light at 222 nm through cell sheets.

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UV light at 222 nm could be one of promising tools to be required for the sterilization in the field of regenerative therapy.

Conjugating Aptamer and Mitomycin C with Reductant-Responsive Linker Leading to Synergistically Enhanced Anticancer Effect

Mitomycin C (MMC) has been using for the treatment of a variety of digestive tract cancers. However, its nonspecific DNA-alkylating ability usually causes severe side effects, thus largely limiting its clinical applications. The utilization of an efficient active targeted drug delivery technique would address this issue. Accordingly, we report the design and development of aptamer-mitomycin C conjugates that use different cross-linking chemistry. The targeted delivery ability and cytotoxicity of these conjugates were carefully studied. It is worth noting that a linker-dependent cytotoxicity effect was observed for these conjugates. The use of a reductant-sensitive disulfide bond cross-linking strategy resulted in significantly enhanced cytotoxicity of MMC against the target cancer cell lines. Importantly, this cytotoxicity enhancement was suited to different types of aptamers, demonstrating the success of our design. Mechanistic studies of the enhanced cytotoxicity effect indicated that the target recognition, specific binding, and receptor-mediated internalization of aptamer were also critical for the observed effect.

Concepts of nanoparticle cellular uptake, intracellular trafficking, and kinetics in nanomedicine

Nanoparticle-based therapeutics and diagnostics are commonly referred to as nanomedicine and may significantly impact the future of healthcare. However, the clinical translation of these technologies is challenging. One of these challenges is the efficient delivery of nanoparticles to specific cell populations and subcellular targets in the body to elicit desired biological and therapeutic responses. It is critical for researchers to understand the fundamental concepts of how nanoparticles interact with biological systems to predict and control in vivo nanoparticle transport for improved clinical benefit. In this overview article, we review and discuss cellular internalization pathways, summarize the field`s understanding of how nanoparticle physicochemical properties affect cellular interactions, and explore and discuss intracellular nanoparticle trafficking and kinetics. Our overview may provide a valuable resource for researchers and may inspire new studies to expand our current understanding of nanotechnology-biology interactions at cellular and subcellular levels with the goal to improve clinical translation of nanomedicines.