This minireview highlights recent advances on the application of embedded 3D bioprinting concepts for the fabrication of in vitro models.

The ability to specifically silence genes by RNA interference has an enormous potential for treating genetic diseases. However, different drawbacks such as short interfering RNA (siRNA) degradability by serum nucleases and biodistribution issues still need to be overcome to develop suitable delivery vehicles that have been proven essential in carrying siRNA to its target. Chitosan is an attractive biomaterial to construct gene nanocarriers as it is safe, cheap, and amenable to chemical modifications. However, the transfection efficiency of nanovectors based on unmodified chitosan has revealed to be relatively low and dependent on different factors such as the biopolymer molecular weight, deacetylation degree, charge ratio, pH, or particle size. Thus, specific strategies have been adopted to improve the transfection efficacy of chitosan-based nanovectors. In this work, hydrophobically modified chitosans with 8-, 10-, and 12-carbon side chains grafted to the polymeric backbone by a reductive amination process were used to develop polymeric nanoparticles by the ionotropic gelation method. After chitosan modification, the produced nanoparticles showed a suitable combination of size and surface charge with high siRNA loading capacities, efficient protection against serum nucleases, and satisfactory in vitro release profiles. Importantly, the introduced structural modifications were observed to modulate the overall physicochemical characteristics of the nanoparticles including their biological performance like their cell viability, uptake, and transfection efficiency. In this regard, the knockdown activity of the prepared nanoparticles was tested in HeLa cells overexpressing the green fluorescent protein after 24 and 48 h of incubation, observing a silencing activity greater than that displayed by the commercial transfection agent Lipofectamine 2000.

Atherosclerosis is an underlying risk factor in cardiovascular diseases (CVDs). The combination of drugs with microRNAs (miRNA) inside a single nanocarrier has emerged as a promising anti-atherosclerosis strategy to achieve the exploitation of their complementary mechanisms of action to achieve synergistic therapeutic effects while avoiding some of the drawbacks associated with current systemic statin therapies. We report the development of nanometer-sized polymeric PLGA nanoparticles (NPs) capable of simultaneously encapsulating and delivering miRNA-124a and the statin atorvastatin (ATOR). The polymeric NPs were functionalized with an antibody able to bind to the vascular adhesion molecule-1 (VCAM1) overexpressed in the inflamed arterial endothelium. The dual-loaded NPs were non-toxic to cells in a large range of concentrations, successfully attached overexpressed VCAM receptors and released the cargoes in a sustainable manner inside cells. The combination of both ATOR and miRNA drastically reduced the levels of proinflammatory cytokines such as IL-6 and TNF-α and of reactive oxygen species (ROS) in LPS-activated macrophages and vessel endothelial cells. In addition, dual-loaded NPs precluded the accumulation of low-density lipoproteins (LdL) inside macrophages as well as morphology changes to a greater extent than in single-loaded NPs. The reported findings validate the present NPs as suitable delivery vectors capable of simultaneously targeting inflamed cells in atherosclerosis and providing an efficient approach to combination nanomedicines.