This work introduces a novel chitosan-based siRNA nanoparticle delivery system for RNA interference in vitro and in vivo. The formation of interpolyelectrolyte complexes between siRNA duplexes (21-mers) and chitosan polymer into nanoparticles, ranging from 40 to 600 nm, was shown using atomic force microscopy and photon correlation spectroscopy. Rapid uptake (1 h) of Cy5-labeled nanoparticles into NIH 3T3 cells, followed by accumulation over a 24 h period, was visualized using fluorescence microscopy. Nanoparticle-mediated knockdown of endogenous enhanced green fluorescent protein (EGFP) was demonstrated in both H1299 human lung carcinoma cells and murine peritoneal macrophages (77.9% and 89.3% reduction in EGFP fluorescence, respectively). In addition, Western analysis showed approximately 90% reduced expression of BCR/ABL-1 leukemia fusion protein while BCR expression was unaffected in K562 (Ph(+)) cells after transfection using nanoparticles containing siRNA specific to the BCR/ABL-1 junction sequence. Effective in vivo RNA interference was achieved in bronchiole epithelial cells of transgenic EGFP mice after nasal administration of chitosan/siRNA formulations (37% and 43% reduction compared to mismatch and untreated control, respectively). These findings highlight the potential application of this novel chitosan-based system in RNA-mediated therapy of systemic and mucosal disease.

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Biomacromolecules have transformed our capacity to effectively treat diseases; however, their rapid degradation and poor absorption in the gastrointestinal (GI) tract generally limit their administration to parenteral routes. An oral biologic delivery system must aid in both localization and permeation to achieve systemic drug uptake. Inspired by the leopard tortoise’s ability to passively reorient, we developed an ingestible self-orienting millimeter-scale applicator (SOMA) that autonomously positions itself to engage with GI tissue. It then deploys milliposts fabricated from active pharmaceutical ingredients directly through the gastric mucosa while avoiding perforation. We conducted in vivo studies in rats and swine that support the applicator’s safety and, using insulin as a model drug, demonstrated that the SOMA delivers active pharmaceutical ingredient plasma levels comparable to those achieved with subcutaneous millipost administration.

Insulin and other injectable biologic drugs have transformed the treatment of patients suffering from diabetes. Patients and healthcare providers, however, prefer the oral route of administration, yet macromolecule drugs are not readily absorbed into the bloodstream through the gastrointestinal tract. We developed an ingestible capsule, termed the luminal unfolding

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