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Humans are intentionally exposed to gold nanoparticles (AuNPs) where they are used in variety of biomedical applications as imaging and drug delivery agents as well as diagnostic and therapeutic agents currently in clinic and in a variety of upcoming clinical trials. Consequently, it is critical that we gain a better understanding of how physiochemical properties such as size, shape, and surface chemistry drive cellular uptake and AuNP toxicity in vivo. Understanding and being able to manipulate these physiochemical properties will allow for the production of safer and more efficacious use of AuNPs in biomedical applications. Here, AuNPs of three sizes, 5 nm, 10 nm, and 20 nm, were coated with a lipid bilayer composed of sodium oleate, hydrogenated phosphatidylcholine, and hexanethiol. To understand how the physical features of AuNPs influence uptake through cellular membranes, sum frequency generation (SFG) was utilized to assess the interactions of the AuNPs with a biomimetic lipid monolayer composed of a deuterated phospholipid 1.2-dipalmitoyl-d62-sn-glycero-3-phosphocholine (dDPPC). SFG measurements showed that 5 nm and 10 nm AuNPs are able to phase into the lipid monolayer with very little energetic cost, whereas, the 20 nm AuNPs warped the membrane conforming it to the curvature of hybrid lipid-coated AuNPs. Toxicity of the AuNPs were assessed in vivo to determine how AuNP curvature and uptake influence cell health. In contrast, in vivo toxicity tested in embryonic zebrafish showed rapid toxicity of the 5 nm AuNPs, with significant 24 hpf mortality occurring at concentrations ≥20 mg/L, whereas the 10 nm and 20 nm AuNPs showed no significant mortality throughout the five-day experiment. By combining information from membrane models using SFG spectroscopy with in vivo toxicity studies, a better mechanistic understanding of how nanoparticles (NPs) interact with membranes is developed to understand how the physiochemical features of AuNPs drive nanoparticle-membrane interactions, cellular uptake, and toxicity.

Tissue engineering and regenerative medicine aim to achieve functional restoration of tissue or cells damaged through disease, aging, or trauma. Advancement of tissue engineering requires innovation in the field of three-dimensional scaffolding and functionalization with bioactive molecules. Nanotechnology offers advanced materials with patterned nano-morphologies for cell growth and different molecular substrates that can support cell survival and functions. Cerium oxide nanoparticles (nanoceria) can control intracellular as well as extracellular reactive oxygen and nitrogen species. Recent findings suggest that nanoceria can enhance long-term cell survival, enable cell migration and proliferation, and promote stem cell differentiation. Moreover, the self-regenerative property of nanoceria permits a small dose to remain catalytically active for an extended time. This review summarizes the possibilities and applications of nanoceria in the field of tissue engineering and regenerative medicine.

Fast and significant progress has been achieved in the development of new biomarkers in recent years providing promising approaches for the reliable detection of diseases at an early stage. Yet, the disadvantages of commonly used markers, including photobleaching, autofluorescence, phototoxicity, and scattering, when ultraviolet or visible light is used for excitation, need to be overcome. Lanthanide-doped host materials are well known for their excellent optical properties, such as their ability to (up)convert near-infrared excitation to higher energies spanning the ultraviolet, visible, and near-infrared regions or to undergo strong near-infrared luminescence following near-infrared excitation. Their application as biomarkers may overcome the aforementioned drawbacks of conventional dyes. Thus, lanthanide-based nanostructures are highly promising candidates for cellular and small animal imaging, while the assessment of their cytotoxicity remains a crucial issue. Recent developments in the field of upconversion and near-infrared bioimaging focusing on some of the latest results obtained in in vitro and in vivo studies assessing the toxicity of lanthanide-based nanophosphors are highlighted in this review.

Engineered nanoparticles, in particular metal oxide nanoparticles, with their unique and novel properties, enable a plethora of new applications in various fields of research. These new properties have raised concerns about potential adverse effects for the environment and human health and are nowadays very controversial. A reliable, cost- and time-effective, rapid and mechanistic-based testing strategy is needed to replace current conventional phenomenological assessments. Today’s in vitro technology, providing human-based advanced cellular models representing different organ barriers such as skin, lung, placenta, or liver, may cover this need. The aim of this article is to present the current changes in (nano) toxicology strategies, the extent to which in vitro models have achieved general acceptance, and how the relevance of these models can further be improved using examples of selected metal oxide nanoparticles.

Neurological pathologies and nerve damage are two problems of significant medical and economic impact because of the hurdles of losing nerve functionality in addition to significant mortality and morbidity, and demanding rehabilitation. There are currently a number of examples of how nanotechnology can provide new solutions for biomedical problems. Current strategies for nerve repair rely on the use of functionalized scaffolds working as “nerve guidance channels” to improve axonal regeneration and to direct axonal re-growth across the nerve lesion site. Since low invasiveness and high selectivity of the growth stimulation are usually conflicting requirements, new approaches are being pursued in order to overcome such limitations. Engineered magnetic nanoparticles (MNPs) have emerged from this need for noninvasive therapies for both positioning and guiding neural cells in response to an external magnetic field. Here, we review the current state of the use of MNPs for neuroprotective and magnetically guided therapies. We discuss some conceivable outcomes of current magnetically driven strategies seeking integrated platforms for regenerative action on damaged tissues.

Metal and metal oxide nanoparticles are an important class of materials with numerous applications. Understanding how such nanoparticles interact with living systems is of considerable relevance both from a toxicological and biomedical perspective. The physicochemical features of nanoparticles are sometimes referred to as the synthetic identity, while the acquired properties of nanoparticles in a biological milieu resulting from the adsorption of biomolecules on the surface of the particles can be considered the biological identity. In this article, we explore the dynamic changes in the identity of nanoparticles resulting either from acquisition of a so-called bio-corona or through the process of biotransformation and how this impacts cellular recognition of nanoparticles and toxicological outcomes, with an emphasis on inflammation—an orchestrated host response against harmful stimuli, including pathogens as well as particles.

Engineered nanomaterials (ENMs) strongly interact with biomolecules and cells due to their similar size scales. Consequently, ENMs are beginning to emerge as new medical diagnostic tools, probes in cell biology, and delivery vehicles, compelling us to understand the interactions at the nano-bio interface. Optical spectroscopic tools are excellent probes to characterize ENMs and investigate their interactions with complex biological systems, including biomolecules, cells, and even whole animals alike. Here, we discuss the role of many optical spectroscopic techniques such as fluorescence, Raman, surface plasmon, and infrared spectroscopy in elucidating nano-bio interactions. While these spectroscopic tools have the ability to provide valuable information on ENM distribution in biosystems, ENM interaction with proteins, and the mechanisms by which ENMs elicit an adverse physiological response, there are many challenges that remain to be addressed to improve their scope, resolution, and throughput.

The biological effects of engineered nanoparticles are presently a focus of interest in chemistry, biology, pharmacology, clinical medicine, and toxicology due to the enormous therapeutic and diagnostic potential that the particulate nature of nanoparticles offers for selective drug delivery and controlled release. This raises unprecedented safety issues, calling for novel paradigms to face the biocompatibility analysis of particulate (as opposed to molecular) bioactive agents that vary in shape, surface, and charge, in addition to chemical structure. This issue of MRS Bulletin focuses on the bioeffects of metal oxide nanostructures, whose high bioactivity can be exploited to design novel multifunctional devices for nanomedical applications, some of which are already undergoing testing in anticancer and antioxidant clinical trials. The ubiquitous application in research and technology of these non-biodegradable structures has evoked concerns regarding their potential hazards, due to the same chemical activities that promise nanomedical developments. A Janus-type scenario is emerging, pointing to intricate networks of beneficial and detrimental effects following the biological interactions of metal oxide nanoparticles.

Neutron activation analysis of the Pleurotus ostreatus showed that adding of solid solution of ZrO[2]-Y[2]O[3] hydroxide and oxide (3 mol % Y[2]O[3]) nanoparticles of size 4 and 9 nm at a concentration of 0.2 weight percent in a nutrient medium (Czapek) alters the character of physiological processes in the biological tissues of the mushrooms. This is manifested in the form of a significant change in morphological and physiological characteristics of the mushrooms and the elemental composition of the dry biomass. In particular, it is shown that the intercalation of nanoparticles into the tissues of the mushrooms leads to an increase of 1.3-1.4 times (more than 2.6 g/dm[3]) of biomass accumulation (industrial strain HK 35) and decrease of 1.7-1.8 times (below 1.7-2.5 mg/mm[3]) of concentrations of extracellular proteins into the culture fluid at a substantially constant value of the acidity. It is shown that the addition of ZrO[2]+3 mol % Y[2]O[3] nanoparticles of sizes 4 or 9 nm into tissue of mushroom at step of the mother mycelium in very small concentrations can alter effectively the chemical composition of the substances produced by the cells and consequently, its physiological activity. It is shown that the use of low concentrations of ZrO[2] nanoparticles allow to increase the yield and resistance of crops to diseases up to 1.2-1.5 times, as well as in the long term can be used in biomedical technologies for the treatment of cancer diseases.