Multiparametric approach for the evaluation of lipid nanoparticles for siRNA delivery

Abstract

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 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 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-functionactivity relationships, improve the in vitro screening process of nanoparticles before in vivo use, and facilitate the future design of potent nanocarriers.RNAi | thiol-yne | gene silencing | drug carrier

Modular degradable dendrimers enable small RNAs to extend survival in an aggressive liver cancer model

“…Lead dendrimers possessed an apparent pK a between 6.3 and 6.6 (SI Appendix, Fig. S8), which is in good agreement with other studies of lipid and lipidoid NPs (8)(9)(10).…”

“…S ince the discovery of RNAi and the recognition of its therapeutic potential, there has been a continuous search for optimal delivery carriers (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). Tremendous progress has been made with regard to delivery efficacy of small RNAs to healthy livers, but the clinically required combination of high delivery potency to tumors and low hepatotoxicity is not currently met by existing delivery vehicles.…”

“…Studies of lipid and polymer carriers have implicated at least two common elements: chemical groups to bind small RNAs and nanoparticle (NP)-stabilizing hydrophobicity, which combine to encapsulate RNA molecules inside stable NPs and release small RNAs into the cytosol after endocytosis (35). Particular tertiary amines with optimal pK a , alkyl chains, and defined topology/ structure have been identified in effective carriers (2)(3)(4)(5)(6)(7)(8)(9)(10)(35)(36)(37).…”

Dual bioluminescence and near-infrared fluorescence monitoring to evaluate spherical nucleic acid nanoconjugate activity in vivo

“…MGMT silencing, in turn, significantly enhanced the antitumor activity of systemically administered TMZ. Significant advances in optimizing siRNA-based nanotherapeutics have been made in recent years (10,11), and the clinical use of this class of therapeutics is now a reality (12). Increasing application of siRNA nanotherapeutics requires the development of relevant preclinical models for evaluating target knockdown, as well as the biologic effects of target knockdown, to test and identify administration regimens appropriate for clinical translation.…”

Development of nucleic acid vaccines: use of self-amplifying RNA in lipid nanoparticles

“…47 To deliver RNA efficiently, several limiting steps must be overcome, including dissociation from the nanocarrier, cellular uptake, endosomal escape, and appropriate intracellular disassembly. 50 The relationship between the physicochemical properties of the nanocarrier (particle size, RNA entrapment, acid dissociation constant) and biological barriers (for instance, cellular uptake), and that between biological barriers and RNA activity remain unclear. 51 This lack of clarity is one of the reasons for poor in vitro-in vivo translation.…”