Unravelling the role of individual components in pBAE/polynucleotide polyplexes in the synthesis of tailored carriers for specific applications: on the road to rational formulations

PExM: polyplex expansion microscopy for cell trafficking studies

Nanomedicine is a field at the intersection of nanotechnology and medicine, promising due to its potential to revolutionize healthcare. Despite its long trajectory, there is still a long road ahead for its full development, and smart design of nanomedicines is still a challenge. Among other problems, this is due to the scarcity of tools available for the precise visualization and comprehension of nano-bio interactions, impeding progress towards the clinical phase. One of the developed tools that stands out to be a strong nanoscopy technique for studying nano-delivery systems within cellular environments is expansion microscopy (ExM). This technique was used for tissue and cell expansion and most recently for lipid molecule expansion inside cells. Herein, we present for the first time polyplex expansion microscopy (PExM); a comprehensive examination of ExM as an already developed technique, but adapted for expanding polymer based nanocarriers, in particular polyplexes within cells, allowing the analysis of their trafficking. With our method set up, PExM will be extensively used for the study of polyplex nanoparticle cell trafficking, becoming a high-resolution technique which can also be applied to primary amine containing polymeric nanoparticles without requiring expensive super-resolution microscopes.

Liver-targeted nanoparticles delivering nitric oxide reduce portal hypertension in cirrhotic rats

Nitric oxide (NO) is a small vasodilator playing a key role in the pathogenesis of portal hypertension. Here, we assessed the potential therapeutic effect of a NO donor targeted to the liver by poly(beta-amino ester) nanoparticles (pBAE NPs) in experimental cirrhosis. Retinol-functionalized NO donor pBAE NPs (Ret pBAE NPs) were synthetized with the aim of actively targeting the liver. Administration of Ret pBAE NPs resulted in uptake and transfection by the liver and spleen. NPs were not found in other organs or the systemic circulation. Treatment with NO donor Ret pBAE NPs (30 mg/ kg body weight) significantly decreased aspartate aminotransferase, lactate dehydrogenase and portal pressure (9.75 ± 0.64 mmHg) compared to control NPs (13.4 ± 0.53 mmHg) in cirrhotic rats. There were no effects on mean arterial pressure and cardiac output. Liver-targeted NO donor NPs reduced collagen fibers and steatosis, activation of hepatic stellate cells and mRNA expression of profibrogenic and proinflammatory genes. Finally, Ret pBAE NPs displayed efficient transfection in human liver slices. Overall, liver-specific NO donor NPs effectively target the liver and mitigated inflammation and portal hypertension in cirrhotic rats. The use of Ret pBAE may prove to be an effective therapeutic strategy to treat advanced liver disease.

Engineering oncogene-targeted anisamide-functionalized pBAE nanoparticles as efficient lung cancer antisense therapies

Non-small cell lung cancer (NSCLC) is one of the leading causes of worldwide death, mainly due to the lack of efficient and safe therapies. Currently, NSCLC standard of care for consist on the use of traditional chemotherapeutics, non-selectively distributed through the whole body, thus causing severe side effects while not achieving high efficacy outcomes. Consequently, the need of novel therapies, targeted to modify specific subcellular routes aberrantly expressed only in tumor cells is still urgent. In this context, the delivery of siRNAs that can know-down overexpressed oncogenes, such as mTOR, could become the promised targeted therapy. However, siRNA effective delivery remains a challenge due to its compromised stability in biological fluids and its inability to cross biological and plasmatic membranes. Therefore, polymeric nanoparticles that efficiently encapsulate siRNAs and are selectively targeted to tumor cells could play a pivotal role. Accordingly, we demonstrate in this work that oligopeptide end-modified poly(beta aminoester) (OM-pBAE) polymers can efficiently complex siRNA in small nanometric particles using very low polymer amounts, protecting siRNA from nucleases attack. These nanoparticles are stable in the presence of serum, advantageous fact in terms of in vivo use. We also demonstrated that they efficiently transfect cells in vitro, in the presence of serum and are able to knock down target gene expression. Moreover, we demonstrated their antitumor efficacy by encapsulating mTOR siRNA, as a model antisense therapy, which showed specific lung tumor cell growth inhibition in vitro and in vivo. Finally, through the addition of anisamide functionalization to the surface of the nanoparticles, we proved that they become selective to lung tumor cells, while not affecting healthy cells. Therefore, our results are a first step in the discovery of a tumor cell-targeted efficient silencing nanotherapy for NSCLC patients survival improvement.