Messenger RNA (mRNA) is not an attractive candidate for gene therapy due to its instability and has therefore received little attention. Recent studies show the advantage of mRNA over DNA, especially in cancer immunotherapy and vaccine development. This study aimed to formulate folic-acid-(FA)-modified, poly-amidoamine-generation-5 (PAMAM G5D)-grafted gold nanoparticles (AuNPs) and to evaluate their cytotoxicity and transgene expression using the luciferase reporter gene (FLuc-mRNA) in vitro. Nanocomplexes were spherical and of favorable size. Nanocomplexes at optimum nanoparticle:mRNA (w/w) binding ratios showed good protection of the bound mRNA against nucleases and were well tolerated in all cell lines. Transgene expression was significantly (p < 0.0001) higher with FA-targeted, dendrimer-grafted AuNPs (Au:G5D:FA) in FA receptors overexpressing MCF-7 and KB cells compared to the G5D and G5D:FA NPs, decreasing significantly (p < 0.01) in the presence of excess competing FA ligand, which confirmed nanocomplex uptake via receptor mediation. Overall, transgene expression of the Au:G5D and Au:G5D:FA nanocomplexes exceeded that of G5D and G5D:FA nanocomplexes, indicating the pivotal role played by the inclusion of the AuNP delivery system. The favorable properties imparted by the AuNPs potentiated an increased level of luciferase gene expression.

Cancer and COVID-19 have been deemed as world health concerns due to the millions of lives that they have claimed over the years. Extensive efforts have been made to develop sophisticated, site-specific, and safe strategies that can effectively diagnose, prevent, manage, and treat these diseases. These strategies involve the implementation of metal nanoparticles and metal oxides such as gold, silver, iron oxide, titanium oxide, zinc oxide, and copper oxide, formulated through nanotechnology as alternative anticancer or antiviral therapeutics or drug delivery systems. This review provides a perspective on metal nanoparticles and their potential application in cancer and COVID-19 treatments. The data of published studies were critically analysed to expose the potential therapeutic relevance of green synthesized metal nanoparticles in cancer and COVID-19. Although various research reports highlight the great potential of metal and metal oxide nanoparticles as alternative nanotherapeutics, issues of nanotoxicity, complex methods of preparation, biodegradability, and clearance are lingering challenges for the successful clinical application of the NPs. Thus, future innovations include fabricating metal nanoparticles with eco-friendly materials, tailor making them with optimal therapeutics for specific disease targeting, and in vitro and in vivo evaluation of safety, therapeutic efficiency, pharmacokinetics, and biodistribution.

Cancer and infectious diseases such as Ebola, HIV, tuberculosis, Zika, hepatitis, measles and human schistosomiasis are serious global health hazards. The increasing annual morbidities and mortalities of these diseases have been blamed on drug resistance and the inefficacy of available diagnostic tools, particularly those which are immunologically-based. Antibody-based tools rely solely on antibody production for diagnosis and for this reason they are the major cause of diagnostic delays. Unfortunately, the control of these diseases depends on early detection and administration of effective treatment therefore any diagnostic delay is a huge challenge to curbing these diseases. Hence, there is a need for alternative diagnostic tools, discovery and development of novel therapeutic agents. Studies have demonstrated that aptamers could potentially offer one of the best solutions to these problems. Aptamers are short sequences of either DNA or RNA molecules, which are identified in vitro through a SELEX process. They are sensitive and bind specifically to target molecules. Their promising features suggest they may serve as better diagnostic agents and can be used as drug carriers for therapeutic purposes. In this article, we review the applications of aptamers in the theranostics of cancer and some infectious diseases.

Health issues involving inadequate treatment of diseases such as cancer and microbial infections continue to be the subject of much ongoing recent research. Biosynthesized silver nanoparticles (AgNPs) were characterized using Transmission Electron Microscopy (TEM), Zeta Sizer, Ultraviolet (UV), and Fourier Transform Infrared (FTIR) spectroscopy. Their antimicrobial activity was evaluated on selected Gram-positive and Gram-negative bacterial strains, using the disc diffusion and broth dilution assays. Cell viability profiles were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis studies on selected human noncancer and cancer cells. The biosynthesized AgNPs were evaluated to be spherical clusters, with sizes between 40 and 70nm. The absorption peak at 423nm and the presence of polyphenols confirmed the synthesis and stabilization of these tested AgNPs. The AgNPs showed a good stability of 23.9±1.02mV. Good antimicrobial activity (6.018.0mm) was seen on all tested bacteria at a minimum inhibitory concentration (MIC) ranging from 5 to 16μg/ml, with the highest activity seen against Gram-negative Escherichia coli (18±0.5mm), and the lowest activity was seen against Gram-positive Listeria monocytogenes (6.0±0.4mm) after treatment with the AgNPs. These NPs showed a concentration-dependent and cell-specific cytotoxicity with low IC₅₀ values (41.7, 56.3, and 63.8μg/ml). The NPs were well tolerated by tested cells as indicated by a more than 50 cell viability at the high dose tested and low apoptotic indices (<0.2). These findings indicated that these biosynthesized AgNPs showed great potential as effective antibacterial agents and anticancer drug delivery modalities.

Background: Selenium, an essential micronutrient, has been studied for decades for its anticancer properties. Selenium nanoparticles (SeNPs) have now emerged as an interesting alternative for drug and gene delivery. Aims: We aimed to demonstrate in proof of principle, the potential use of SeNPs in targeted pCMVLuc DNA (pDNA) delivery in vitro. Objectives: To chemically synthesize, characterize and evaluate the transgene expression of functionalized SeNPs in five human cell lines. Methods: SeNPs were synthesized via chemical reduction, coated with chitosan (Ch) and a targeting moiety, folic acid (FA). All nanoparticles were characterized by transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), UV-vis and Fourier transform infra-red (FTIR) spectroscopy. Nanoparticle:pDNA interactions were assessed using the electrophoretic mobility shift, dye displacement and nuclease protection assays. The MTT and Luciferase reporter gene assays were used to determine cytotoxicity and transgene expression, respectively, in the human colorectal adenocarcinoma (HT-29 and Caco-2), breast adenocarcinoma (MCF-7), oral epidermoid/cervical carcinoma contaminant (KB) and the embryonic kidney (HEK293) cells. Results: Homogenous nanoparticles of 60-70 nm were able to successfully bind, compact and protect the pDNA from enzyme digestion. Low cytotoxicity was observed in all cells, except for the MCF-7 cells, which could be attributed to apoptosis and necrosis. Luciferase gene expression was highest for the targeted nanocomplexes in the folate-receptor rich KB cell line, confirming nanocomplex uptake through folate receptor-mediated endocytosis. Conclusion: This study opens a new avenue for synergistic treatment of cancer, combining selenium’s bioactivity and its carrier potential for therapeutic gene delivery.

Bimetallic nanosized delivery systems are attracting a lot of research interest as alternatives to monometallic delivery systems. This study evaluated the ability of bimetallic selenium silver chitosan pegylated folic acid targeted nanoparticles (SeAgChPEGFA NPs) to deliver doxorubicin (DOX) in cervical cancer cells. Comparison studies using monometallic selenium chitosan pegylated folic acid (SeChPEGFA NPs) targeted NPs and free DOX were also conducted. The prepared NPs and their drug nanocomplexes were characterised morphologically and physico-chemically. Drug binding and releasing studies were conducted under a simulated environment in vitro . The cytotoxicity and apoptosis studies were studied using the 3-[(4, 5-dimethylthiazol-2-yl)−2, 5-diphenyl tetrazolium bromide] (MTT) assay and the dual dye staining. The findings revealed that the bimetallic SeAgChPEGFA NPs displayed better colloidal stability, superior physico-chemical qualities, and higher binding abilities in comparison with monometallic SeChPEGFA NPs. In addition, the SeAgChPEGFA NPs showed the pH-triggered controlled drug release and cell-specific cytotoxicity. These findings suggest that the bimetallic NPs are superior delivery systems when compared to their monometallic NPs and free drug counterparts, thus, setting a platform for further in vivo examination.