Nanoparticles and Their Applications

Therapeutic applications of nanobiotechnology

Nanobiotechnology, as a novel and more specialized branch of science, has provided a number of nanostructures such as nanoparticles, by utilizing the methods, techniques, and protocols of other branches of science. Due to the unique features and physiobiological characteristics, these nanostructures or nanocarriers have provided vast methods and therapeutic techniques, against microbial infections and cancers and for tissue regeneration, tissue engineering, and immunotherapies, and for gene therapies, through drug delivery systems. However, reduced carrying capacity, abrupt and non-targeted delivery, and solubility of therapeutic agents, can affect the therapeutic applications of these biotechnological products. In this article, we explored and discussed the prominent nanobiotechnological methods and products such as nanocarriers, highlighted the features and challenges associated with these products, and attempted to conclude if available nanostructures offer any scope of improvement or enhancement. We aimed to identify and emphasize the nanobiotechnological methods and products, with greater prospect and capacity for therapeutic improvements and enhancements. We found that novel nanocarriers and nanostructures, such as nanocomposites, micelles, hydrogels, microneedles, and artificial cells, can address the associated challenges and inherited drawbacks, with help of conjugations, sustained and stimuli-responsive release, ligand binding, and targeted delivery. We recommend that nanobiotechnology, despite having few challenges and drawbacks, offers immense opportunities that can be harnessed in delivering quality therapeutics with precision and prediction. We also recommend that, by exploring the branched domains more rigorously, bottlenecks and obstacles can also be addressed and resolved in return.

Synthesis and Biological Characterization of Phyto-Fabricated Silver Nanoparticles from Azadirachta indica

Nanoparticles (NPs) have garnered a lot of interest in sectors like medicine, cosmetics, food, and pharmaceuticals for antibacterial catalytic properties, reduced toxicity, and easy production. Biological synthesis of silver nanoparticle (AgNPs) is considered as green, eco-friendly, and cost-effective approach; therefore, Azadirachta indica extracts were utilized for a dual role of fabrication and functionalization of AgNPs. Optical and physical characterizations were achieved for confirming the biosynthesized AgNPs. SEM images detected quasi-spherical AgNPs of 44.04 to 66.50 nm. Some of potent phytochemicals like flavonoids and proteins from Azadirachta indica formed a strong coating or capping on the AgNPs without affecting their secondary structure by interacting with Ag+ and NPs for the formation of AgNPs. AgNPs exhibited strong antibacterial activity (MIC 10 μg/ml) against multidrug-resistant bacteria Enterococcus faecalis; at different concentrations, no IC50 values were recorded for AgNPs as well as Azadirachta indica signifying low cytotoxicity in the exposed concentration range. The DNA degradation activity of AgNPs through the TUNEL assay revealed no significant increase in the overall FITC mean fluorescence intensity as well as a DNA fragmentation index with 5.45% DNA damage (10 μg/ml AgNPs). Drug uptake of AgNPs was also investigated through a permeability assay via Caco-2 cell lines at test concentrations where apparent permeability was detected as moderate.

In vitro DNA plasmid condensation and transfection through pH-responsive nanohydrogel

Nanohydrogels (NHs) with the benefits of both nanomaterials and hydrogels unlock novel opportunities and applications in biomedicine. Nowadays, cationic NHs have attracted attention in the delivery of genetic materials into cells. Herein, by using reversible addition-fragmentation chain transfer method, an NH-based poly(hydroxyethyl methacrylate-co-N,N-dimethylaminoethyl methacrylate) and cross-linked by poly(ethylene glycol)diacrylate with pH responsiveness character was developed. Several techniques including nuclear magnetic resonance, Fourier-transform infrared spectroscopy, and gel permeation chromatography confirmed the success in the synthesis. The pH responsiveness of the developed NH was shown by transmission electron microscopy and dynamic light scattering technique. The average sizes of NHs in the normal (7.4) and acidic pH (5.5) were 180 and 390 nm, respectively. The ability of the developed NH to condense genetic materials was checked using gel retardation assay with different ratios of NH and pCMV6-IRES-AcGFP, as a plasmid encoding green fluorescence protein. Results of gel retardation assay showed a decreasing trend in plasmid electrophoretic mobility with the increase in the NH concentration. The NH/plasmid complexes were stopped completely at the ratio of 5 and the plasmid band vanished at the ratio of 10. The quantitative and qualitative results of the cell transfection experiment using different ratios of NH/plasmid showed the ability of NH to carry plasmid molecules into the cancerous cells. The best transfection efficiency was observed by nanohydrogel/plasmid weight ratio of 10, while other ratios including 2, 5 and 20 showed 0.8, 10 and 12% of transfection efficiency, respectively. All the assessed factors showed that NH has the potential to be considered as an efficient gene delivery vehicle.

Targeting neuroinflammation by intranasal delivery of nanoparticles in neurological diseases: a comprehensive review

Neuroinflammation (NIF) plays an essential role in the pathology of neurological disorders like Parkinson's disease, Alzheimer's disease, multiple sclerosis, and epilepsy. Despite progress in the drug discovery and development of new drugs, drug delivery to the central nervous system (CNS) still represents the challenge due to the presence of the blood-brain barrier (BBB). Targeting NIF may require an adequate amount of drug to cross the BBB. Recently, the intranasal (IN) drug administration has attracted increasing attention as a reliable method to cross the BBB and treat neurological disorders. On the other hand, using optimized nanoparticles may improve the IN delivery limitations, increase the mucoadhesive properties, and prevent drug degradation. NPs can carry and deliver drugs to the CNS by bypassing the BBB. In this review, we described briefly the NIF as a pathologic feature of CNS diseases. The potential treatment possibilities with IN transfer of NP-loaded drugs will enhance the establishment of more efficient nanoformulations and delivery systems.

The Hitchhiker's Guide to Human Therapeutic Nanoparticle Development

Nanomedicine plays an essential role in developing new therapies through novel drug delivery systems, diagnostic and imaging systems, vaccine development, antibacterial tools, and high-throughput screening. One of the most promising drug delivery systems are nanoparticles, which can be designed with various compositions, sizes, shapes, and surface modifications. These nanosystems have improved therapeutic profiles, increased bioavailability, and reduced the toxicity of the product they carry. However, the clinical translation of nanomedicines requires a thorough understanding of their properties to avoid problems with the most questioned aspect of nanosystems: safety. The particular physicochemical properties of nano-drugs lead to the need for additional safety, quality, and efficacy testing. Consequently, challenges arise during the physicochemical characterization, the production process, in vitro characterization, in vivo characterization, and the clinical stages of development of these biopharmaceuticals. The lack of a specific regulatory framework for nanoformulations has caused significant gaps in the requirements needed to be successful during their approval, especially with tests that demonstrate their safety and efficacy. Researchers face many difficulties in establishing evidence to extrapolate results from one level of development to another, for example, from an in vitro demonstration phase to an in vivo demonstration phase. Additional guidance is required to cover the particularities of this type of product, as some challenges in the regulatory framework do not allow for an accurate assessment of NPs with sufficient evidence of clinical success. This work aims to identify current regulatory issues during the implementation of nanoparticle assays and describe the major challenges that researchers have faced when exposing a new formulation. We further reflect on the current regulatory standards required for the approval of these biopharmaceuticals and the requirements demanded by the regulatory agencies. Our work will provide helpful information to improve the success of nanomedicines by compiling the challenges described in the literature that support the development of this novel encapsulation system. We propose a step-by-step approach through the different stages of the development of nanoformulations, from their design to the clinical stage, exemplifying the different challenges and the measures taken by the regulatory agencies to respond to these challenges.

From Impure to Purified Silver Nanoparticles: Advances and Timeline in Separation Methods

AgNPs have exceptional characteristics that depend on their size and shape. Over the past years, there has been an exponential increase in applications of nanoparticles (NPs), especially the silver ones (AgNPs), in several areas, such as, for example, electronics; environmental, pharmaceutical, and toxicological applications; theragnostics; and medical treatments, among others. This growing use has led to a greater exposure of humans to AgNPs and a higher risk to human health and the environment. This risk becomes more aggravated when the AgNPs are used without purification or separation from the synthesis medium, in which the hazardous synthesis precursors remain unseparated from the NPs and constitute a severe risk for unnecessary environmental contamination. This review examines the situation of the available separation methods of AgNPs from crude suspensions or real samples. Different separation techniques are reviewed, and relevant data are discussed, with a focus on the sustainability and efficiency of AgNPs separation methods.

Bridging the academic-industrial gap: application of an oxygen and pH sensor-integrated lab-on-a-chip in nanotoxicology

Translation of advanced cell-based assays exhibiting a higher degree of automation, miniaturization, and integration of complementary sensing functions is mainly limited by the development of industrial-relevant prototypes that can be readily produced in larger volumes. Despite the increasing number of academic publications in recent years, the manufacturability of these microfluidic cell cultures systems is largely ignored, thus severely restricting their implementation in routine toxicological applications. We have developed a dual-sensor integrated microfluidic cell analysis platform using industrial specifications, materials, and fabrication methods to conduct risk assessment studies of engineered nanoparticles to overcome this academic-industrial gap. Non-invasive and time-resolved monitoring of cellular oxygen uptake and metabolic activity (pH) in the absence and presence of nanoparticle exposure is accomplished by integrating optical sensor spots into a cyclic olefin copolymer (COC)-based microfluidic platform. Results of our nanotoxicological study, including two physiological cell barriers that are essential in the protection from exogenous factors, the intestine (Caco-2) and the vasculature (HUVECs) showed that the assessment of the cells' total energy metabolism is ideally suited to rapidly detect cytotoxicities. Additional viability assay verification using state-of-the-art dye exclusion assays for nanotoxicology demonstrated the similarity and comparability of our results, thus highlighting the benefits of employing a compact and cost-efficient microfluidic dual-sensor platform as a pre-screening tool in nanomaterial risk assessment and as a rapid quality control measure in medium to high-throughput settings.

Ovarian toxicity of nanoparticles

The ovary is a highly important organ for female reproduction. The main functions include sex steroid hormone synthesis, follicular development, and achievement of oocyte meiotic and development competence for proper fertilization. Nanoparticle (NP) exposure is becoming unavoidable because of its wide use in different products, including cosmetics, food, health, and personal care products. Studies examining different nonreproductive tissues or systems have shown that characteristics such as the size, shape, core material, agglomeration, and dissolution influence the effects of NPs. However, most studies evaluating NP-mediated reproductive toxicity have paid little or no attention to the influence of the physicochemical characteristics of NP on the observed effects. As accumulating evidence indicates that NP may reach the ovary to impair proper functions, this review summarizes the available data on NP accumulation in ovarian tissue, as well as data describing toxicity to ovarian functions, including sex steroid hormone production, follicular development, oocyte quality, and fertility. Due to their toxicological relevance, this review also describes the main physicochemical characteristics involved in NP toxicity and the importance of considering NP physicochemical characteristics as factors influencing the ovarian toxicity of NPs. Finally, this review summarizes the main mechanisms of toxicity described in ovarian cells.

Neuroinflammation Treatment via Targeted Delivery of Nanoparticles

The lack of effective treatments for most neurological diseases has prompted the search for novel therapeutic options. Interestingly, neuroinflammation is emerging as a common feature to target in most CNS pathologies. Recent studies suggest that targeted delivery of small molecules to reduce neuroinflammation can be beneficial. However, suboptimal drug delivery to the CNS is a major barrier to modulate inflammation because neurotherapeutic compounds are currently being delivered systemically without spatial or temporal control. Emerging nanomaterial technologies are providing promising and superior tools to effectively access neuropathological tissue in a controlled manner. Here we highlight recent advances in nanomaterial technologies for drug delivery to the CNS. We propose that state-of-the-art nanoparticle drug delivery platforms can significantly impact local CNS bioavailability of pharmacological compounds and treat neurological diseases.