Photocrosslinked Bioreducible Polymeric Nanoparticles for Enhanced Systemic siRNA Delivery as Cancer Therapy

Clinical translation of polymer‐based nanocarriers for systemic delivery of RNA has been limited due to poor colloidal stability in the blood stream and intracellular delivery of the RNA to the cytosol. To address these limitations, this study reports a new strategy incorporating photocrosslinking of bioreducible nanoparticles for improved stability extracellularly and rapid release of RNA intracellularly. In this design, the polymeric nanocarriers contain ester bonds for hydrolytic degradation and disulfide bonds for environmentally triggered small interfering RNA (siRNA) release in the cytosol. These photocrosslinked bioreducible nanoparticles (XbNPs) have a shielded surface charge, reduced adsorption of serum proteins, and enable superior siRNA‐mediated knockdown in both glioma and melanoma cells in high‐serum conditions compared to non‐crosslinked formulations. Mechanistically, XbNPs promote cellular uptake and the presence of secondary and tertiary amines enables efficient endosomal escape. Following systemic administration, XbNPs facilitate targeting of cancer cells and tissue‐mediated siRNA delivery beyond the liver, unlike conventional nanoparticle‐based delivery. These attributes of XbNPs facilitate robust siRNA‐mediated knockdown in vivo in melanoma tumors colonized in the lungs following systemic administration. Thus, biodegradable polymeric nanoparticles, via photocrosslinking, demonstrate extended colloidal stability and efficient delivery of RNA therapeutics under physiological conditions, and thereby potentially advance systemic delivery technologies for nucleic acid‐based therapeutics

Non-Cell-Adhesive Substrates for Printing of Arrayed Biomaterials

Cellular microarrays have become extremely useful in expediting the investigation of large libraries of (bio)materials for both in vitro and in vivo biomedical applications. An exceedingly simple strategy is developed for the fabrication of non-cell-adhesive substrates supporting the immobilization of diverse (bio)material features, including both monomeric and polymeric adhesion molecules (e.g., RGD and polylysine), hydrogels, and polymers. ©2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.NIH-R01 (DE01651

Multiparametric approach for the evaluation of lipid nanoparticles for siRNA delivery

Nanoparticle-mediated siRNA delivery is a complex process that requires transport across numerous extracellular and intracellular barriers. As such, the development of nanoparticles for efficient delivery would benefit from an understanding of how parameters associated with these barriers relate to the physicochemical properties of nanoparticles. Here, we use a multiparametric approach for the evaluation of lipid nanoparticles (LNPs) to identify relationships between structure, biological function, and biological activity. Our results indicate that evaluation of multiple parameters associated with barriers to delivery such as siRNA entrapment, pK[subscript a], LNP stability, and cell uptake as a collective may serve as a useful prescreening tool for the advancement of LNPs in vivo. This multiparametric approach complements the use of in vitro efficacy results alone for prescreening and improves in vitro–in vivo translation by minimizing false negatives. For the LNPs used in this work, the evaluation of multiple parameters enabled the identification of LNP pK[subscript a] as one of the key determinants of LNP function and activity both in vitro and in vivo. It is anticipated that this type of analysis can aid in the identification of meaningful structure–function–activity relationships, improve the in vitro screening process of nanoparticles before in vivo use, and facilitate the future design of potent nanocarriers.National Institutes of Health (U.S.) (Grant R37-EB000244)Alnylam Pharmaceuticals (Firm)National Institutes of Health (U.S.) (Postdoctoral Fellowship

Photocrosslinked Bioreducible Polymeric Nanoparticles for Enhanced Systemic siRNA Delivery as Cancer Therapy

Clinical translation of polymer-based nanocarriers for systemic delivery of RNA has been limited due to poor colloidal stability in the blood stream and intracellular delivery of the RNA to the cytosol. To address these limitations, this study reports a new strategy incorporating photocrosslinking of bioreducible nanoparticles for improved stability extracellularly and rapid release of RNA intracellularly. In this design, the polymeric nanocarriers contain ester bonds for hydrolytic degradation and disulfide bonds for environmentally triggered small interfering RNA (siRNA) release in the cytosol. These photocrosslinked bioreducible nanoparticles (XbNPs) have a shielded surface charge, reduced adsorption of serum proteins, and enable superior siRNA-mediated knockdown in both glioma and melanoma cells in high-serum conditions compared to non-crosslinked formulations. Mechanistically, XbNPs promote cellular uptake and the presence of secondary and tertiary amines enables efficient endosomal escape. Following systemic administration, XbNPs facilitate targeting of cancer cells and tissue-mediated siRNA delivery beyond the liver, unlike conventional nanoparticle-based delivery. These attributes of XbNPs facilitate robust siRNA-mediated knockdown in vivo in melanoma tumors colonized in the lungs following systemic administration. Thus, biodegradable polymeric nanoparticles, via photocrosslinking, demonstrate extended colloidal stability and efficient delivery of RNA therapeutics under physiological conditions, and thereby potentially advance systemic delivery technologies for nucleic acid-based therapeutics