A Kinetic Model of Oligonucleotide–Brush Interactions for the Rational Design of Gene Delivery Vectors

Abstract

Polymer brushes are attractive candidates for the design of gene delivery vectors as they allow the systematic study of the impact of structural (type, size, and shape of nanomaterials core) and physicochemical parameters (cationic monomer chemistry, brush thickness, and grafting density) on transfection efficiency. However, relatively little is known of their interactions of oligonucleotides. To study such interactions, we use surface plasmon resonance and developed a kinetic model of brush binding and infiltration. We identify the striking impact that brush grafting density and thickness have on oligonucleotide kinetics of infiltration, binding affinity, and maximum loading. Surprisingly, double-stranded RNA molecules are found to load at significantly higher levels compared to DNA molecules of identical sequence (apart from uracils/thymines). Furthermore, analysis of the kinetics of adsorption of these oligonucleotides indicates that the stoichiometry of binding (ratio of amine versus phosphate residues) is close to parity for the uptake of 20 bp double-stranded RNA. Finally, nanoparticles were designed to be used as gene transfection vectors and to quantify if the brush grafting density and thickness significantly impact transfection efficiencies in a small interfering RNA knockdown assay. Therefore, this study demonstrates the rational design of polymer brush-based nanoparticle vectors for efficient delivery of oligonucleotides. The model developed will allow to uncover how the refinement of the physicochemical and structural properties of polymer brushes enable the tuning of RNA binding and allow the systematic study of cationic vectors efficiency for RNA delivery.

The physico-chemistry of adhesions of protein resistant and weak polyelectrolyte brushes to cells and tissues

“…The swelling behaviour of PDMAEMA and POEGMA brushes was previously studied by ellipsometry and reported by our group as well as others. 22,54 Fourier Transform Infrared-Attenuated Total Reflectance Spectroscopy (ATR-FTIR) was carried out using a Bruker Tensor 27 with an MCT detector (liquid N 2 cooled). Spectra were acquired at a resolution of 4 cm À1 with a total of 256 scans per run.…”

Competitive binding and molecular crowding regulate the cytoplasmic interactome of non-viral polymeric gene delivery vectors

“…The high density of polymer brushes was found to bind RNA oligonucleotides particularly stably 18 , yet display low cytotoxicity and be amenable to molecular design, including labelling of corresponding nanomaterials 19 . The high density of polymer brushes was found to impact not only the binding capacity of these coatings, but also their kinetics of adsorption, depending on the molecular weight of the macromolecules adsorbed 20 . Hence, this system allows the tailoring of physicochemical parameters regulating RNA adsorption and transfection.…”

Responsive Polymer Brush Design and Emerging Applications for Nanotheranostics

“…For example, PDMAEMA with pendant tertiary amines is a temperature-and pH-responsive polymer, often used as cationic antibacterial surfaces and nonviral gene carriers for biomedical applications. [18,36,94,95] Many other responsive polymer brushes have been developed for use in drug delivery. We have summarized recent advances toward these applications in Table 1.…”

“…Rh6G dye Temperature P(OEGMA-co-MEO2MA) SWCNTs [96] Rh6G dye Temperature PNIPAAm-co-PAAm Au nanocage [97] Rh6G dye pH PDMAEMA MSNs [98] RhB dye pH PDEAEMA MSNs [99] Dye (Calcein) pH P4VP MSNs [ 100] Diol derivatives Saccharide and temperature PNIPAAm-co-PMAA AuNSs [ Doxorubicin, lysozyme Temperature PNIPAAm-co-PAAm Au nanocage [ 116] plasmid DNA pH and temperature PDMAEMA SPIONs [ 117] plasmid DNA pH PDMAEMA SPIONs [ 118] CPT, plasmid DNA pH PDMAEMA GO [ 119] plasmid DNA pH PDMAEMA LDHs [ 120] plasmid DNA pH PDMAEMA Chiral Si nanorods [ 121] plasmid DNA Shielding effect PDMAEMA Spindly CNCs [ 122] siRNA Bioreductivity Poly(DAMA-HEMA) Gold NPs [40] plasmid DNA pH PDMAEMA Silica NPs [36] plasmid DNA, siRNA pH PDMAEMA Silica NPs [95] siRNA pH PDMAEMA Silica NPs [18] siRNA pH PDMAEMA Silica NPs [39] plasmid DNA pH PDMAEMA Nanodiamond (with bioimaging) [ 123] siRNA pH PDMAEMA UCNPs (with phototherapy) [ 124] siPD-L1 Redox SPDP Magnetic nanoparticle (MRI imaging) [ 125] siPD-L1 Redox FA-PEG-SS-PEI SPION (MRI imaging) Applications of responsive polymer brushes for triggered drug delivery. A) PDEAEMA-coated silica nanoparticles and pH-sensitive controlled release of a model dye.…”

“…This was supported by an adsorption model that combined a simple polyelectrolyte surface adsorption model with an infiltration step dependent on brush architecture. [ 95 ] The brush grafting density and thickness were found to greatly impact on the absorption profile of oligonucleotides. For instance, the small oligonucleotides (10 bp) infiltrated relatively fast into the brushes, with a relatively low binding affinity and moderate binding factor (and loading level).…”