Advances in molecular biology have revolutionized the use of messenger RNA (mRNA) as a therapeutic. The concept of nucleic acid therapy with mRNA originated in 1990 when Wolff et al. reported successful expression of proteins in target organs by direct injection of either plasmid DNA or mRNA. It took decades to bring the transfection efficiency of mRNA closer to that of DNA. The next few decades were dedicated to turning in vitro-transcribed (IVT) mRNA from a promising delivery tool for gene therapy into a full-blown therapeutic modality, which changed the biotech market rapidly. Hundreds of clinical trials are currently underway using mRNA for prophylaxis and therapy of infectious diseases and cancers, in regenerative medicine, and genome editing. The potential of IVT mRNA to induce an innate immune response favors its use for vaccination and immunotherapy. Nonetheless, in non-immunotherapy applications, the intrinsic immunostimulatory activity of mRNA directly hinders the desired therapeutic effect since it can seriously impair the target protein expression. Targeting the same innate immune factors can increase the effectiveness of mRNA therapeutics for some indications and decrease it for others, and vice versa. The review aims to present the innate immunity-related ‘barriers’ or ‘springboards’ that may affect the development of immunotherapies and non-immunotherapy applications of mRNA medicines.

Nanoparticles (NPs) are widely used platforms for delivery of various biologically active compounds. Unfortunately, there is a lack of comprehensive investigations that would include a few types of NPs with different physicochemical parameters and their potential use as delivery systems in one tumor model. Therefore, to achieve therapeutic effect via nanocarrier with therapeutic agent, the properties of the developed NPs must be clearly defined. Herein, we report the development and modification of 99mTc and Cy5-labeled NPs based on calcium carbonate (CaCO3) and silica oxide (SiO2) to investigate in vitro and in vivo distribution on an example of a breast cancer model. We describe the synthesis and characterization of these NPs, including their morphology, size distribution, stability in biological media and cytotoxicity. Transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), direct radiometry analysis, and histology were used to collect all data. The cellular uptake of NPs on 4T1 cell linewas shown in vitro and in vivo. As a result, we demonstrated that these NPs are non-toxic, biocompatible, and stable system to use for delivery of bioactive compounds into breast cancer.

The behavior of nanoparticles (NPs) in the body is a complex, multilevel process governed by a cascade of physicochemical and biological interactions. At the molecular level, these processes include protein adsorption and formation of the biomolecular corona, ion release, and surface redox reactions. At the cellular level, they encompass endocytosis, intracellular trafficking, lysosomal processing and clearance, and redistribution within cellular compartments. At the systemic level, NPs undergo tissue and organ biodistribution, biological barrier crossing, biotransformation, biodegradation, elimination, and immunomodulation. Understanding these processes is essential for evaluating the safety, efficacy, and therapeutic potential of nanomedicines, as the unique physicochemical properties of NPs can induce biological responses that differ substantially from those of their bulk counterparts. This review provides an integrated framework for understanding the absorption, distribution, biotransformation, and elimination of NPs in biological systems. Particular emphasis is placed on the molecular and cellular mechanisms governing nanoparticle–biological interactions, including the effects of NPs on cellular energy metabolism through interactions with the mitochondrial electron transport chain and their immunomodulatory effects mediated by nuclear factor κB (NF-κB) signaling and inflammasome activation. By integrating molecular, cellular, and systemic perspectives, this review highlights the key determinants of nanoparticle fate in the body and their implications for the design, safety, and clinical translation of nanomedicines.

Oral delivery of nucleic acid therapeutics offers a promising non-invasive approach for treating gastrointestinal diseases such as inflammatory bowel disease, colorectal cancer, and infections, as well as systemic conditions like diabetes and hemophilia. However, the gastrointestinal tract presents significant barriers, including harsh pH, enzymatic degradation, and mucosal layers, which challenge the stability, bioavailability, and targeting of nucleic acids. This review explores the impact of physicochemical properties of non-viral nano- and microcarriers on overcoming these barriers for effective oral nucleic acid delivery. We discuss various carrier systems, including polymeric, lipid-based, and metal-organic frameworks, focusing on their design strategies for site-specific delivery to the stomach, small intestine, and colon. We highlight key advancements, such as mucoadhesive and pH-responsive carriers, which have demonstrated efficacy in in vivo studies and preclinical models. Despite progress, challenges in scalability, regulatory approval, and clinical translation remain. This review underscores the potential of optimized nucleic acid delivery systems to transform clinical practice while identifying future directions for research and development.