Anionic Polymer and Quantum Dot Excipients to Facilitate siRNA Release and Self-Reporting of Disassembly in Stimuli-Responsive Nanocarrier Formulations

Abstract

The incorporation of anionic excipients into polyplexes is a promising strategy for modulating siRNA binding vs. release and integrating diagnostic capabilities; however, specific design criteria and structure-function relationships are needed to facilitate the development of nanocarrier-based theranostics. Herein, we incorporated poly(acrylic acid) (PAA) and quantum dot (QD) excipients into photolabile siRNA polyplexes to increase gene silencing efficiencies by up to 100% and enable self-reporting of nanocarrier disassembly. Our systematic approach identified the functional relationships between gene silencing and key parameters such as excipient loading fractions and molecular weights that enabled the establishment of design rules for optimization of nanocarrier efficacy. For example, we found that PAA molecular weights ~10–20 times greater than that of the co-encapsulated siRNA exhibited the most efficient release and silencing. Furthermore, siRNA release assays and RNAi modeling allowed us to generate a PAA “heat map” that predicted gene silencing a priori as a function of PAA molecular weight and loading fraction. QDs further promoted selective siRNA release and provided visual as well as Förster resonance energy transfer (FRET)-based monitoring of the dynamic changes in nanostructure in situ. Moreover, even with the addition of anionic components, our formulations exhibited substantially improved stability and shelf-life relative to typical formulations, with complete stability after a week of storage and full activity in the presence of serum. Taken together, this study enabled synergistic improvements in siRNA release and diagnostic capabilities, along with the development of mechanistic insights that are critical for advancing the translation of nucleic acid theranostics into the clinic.

Microwave-Assisted Chitosan-Functionalized Graphene Oxide as Controlled Intracellular Drug Delivery Nanosystem for Synergistic Antitumour Activity

“…Figure 1 a reveals the uniform size distribution of GO nanosheets below 100 nm, with an average size of approximately 45 nm. The high electron density of GO exhibited better contrast compared to chitosan, which is barely visible due to its low electron density and hydrated nature [ 21 ]. Due to the higher surface area, nanoscale GO or reduced GO sheets have been widely used as drug carriers [ 22 ].…”

Dual-targeted therapy in HER2-positive breast cancer cells with the combination of carbon dots/HER3 siRNA and trastuzumab

“…The HRTEM images of BP-CDs/HER3 siRNA complexes demonstrated that the final nanocomplexes are spherical in morphology with good dispersity. The high electron density of N-CD cores exhibits better contrast compared to PEI polymers /siRNA, which are barely visible due to their low electron densities and hydrated nature [31]. The various dark objects identified within the BP-CDs/HER3 siRNA complex structure are ascribed to the presence of electrondense N-CDs.…”

Fluorination Enhances Serum Stability of Bioreducible Poly(amido amine) Polyplexes and Enables Efficient Intravenous siRNA Delivery

“…While beneficial for systemic delivery, the high physiological resistance of fluorous interactions poses unique challenges for siRNA delivery because of the need to release the siRNA inside the target cells . A viable strategy to this conundrum that is proposed here is to exploit the easy intracellular degradation of disulfide bonds, which is the result of a 1000‐fold difference in the intracellular concentrations of glutathione (GSH) when compared with its low micromolar extracellular levels .…”