Two
crystalline and five amorphous benzimidazole polymers (BINP)
were synthesized and conjugated to porous silica via amine and aldehyde-based
materials by a simple reflux procedure. The resulting polymers were
subject to thermal analysis for monitoring and quantification of the
adsorption and desorption of CO2. All the polymers were
capable of adsorbing CO2 from a flowing stream of only
80 mL/min at 25 °C. The adsorbed CO2 onto the polymers
were effectively desorbed at room temperature, illustrating the potential
application of such polymers for repeated adsorption/desorption of
CO2. The CO2 adsorption capacities of these
polymers were dependent upon their nitrogen content, specific surface
area, and pore size. The available nitrogen atoms for binding to the
carbon of CO2 via tetrel bonds also plays an important
role in the capture of this gas. Minimal and much lower CO2 adsorption was also noted with two crystalline polymers, compared
to the five amorphous counterparts. Intermolecular hydrogen bonding
and π–π interaction effectively prevented the polymer
N sites of the crystalline polymers from interacting with polarized
CO2 molecules.
The advent of protein expression using m-RNA applied lately for treating the COVID pandemic, and gene editing using CRISPR/Cas9 technology for introducing DNA sequences at a specific site in the genome, are milestones for the urgent need of developing new nucleic acid delivery systems with improved delivery properties especially for in vivo applications. We have designed, synthesized, and characterized novel cross-linked monodispersed nanohydrogels (NHG’s) with well-defined sizes ranging between 50–400 nm. The synthesis exploits the formation of self-assemblies generated upon heating a thermo-responsive mixture of monomers. Self-assemblies are formed and polymerized at high temperatures resulting in NHGs with sizes that are predetermined by the sizes of the intermediate self-assemblies. The obtained NHGs were chemically reduced to lead particles with highly positive zeta potential and low cell toxicity. The NHGs form complexes with DNA, and at optimal charge ratio the size of the complexes is concomitant with the size of the NHG’s. Thus, the DNA is fully embedded inside the NHGs. The new NHGs and their DNA complexes are devoid of cell toxicity which together with their tunned sizes, make them potential tools for gene delivery and foreign protein expression.
We have developed new formulations of nanohydrogels (NHGs) complexed with DNA devoid of cell toxicity, which, together with their tuned sizes, makes them of great interest for delivering DNA/RNA for foreign protein expression. Transfection results demonstrate that, unlike classical lipo/polyplexes, the new NHGs can be incubated indefinitely with cells without apparent cellular toxicity, resulting in the high expression of foreign proteins for long periods of time. Although protein expression starts with a delay as compared to classical systems, it is sustained for a long period of time, even after passing cells without observation of toxicity. A fluorescently labelled NHG used for gene delivery was detected inside cells very early after incubation, but the protein expression was delayed by many days, demonstrating that there is a time-dependent release of genes from the NHGs. We suggest that this delay is due to the slow but continuous release of DNA from the particles concomitantly with slow but continuous protein expression. Additionally, results obtained after the in vivo administration of m-Cherry/NHG complexes indicated a delayed but prolonged expression of the marker gene in the tissue of administration. Overall, we have demonstrated gene delivery and foreign protein expression using GFP and m-Cherry marker genes complexed with biocompatible nanohydrogels.
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