Receptor-Meditated Endocytosis by Hyaluronic Acid@Superparamagnetic Nanovetor for Targeting of CD44-Overexpressing Tumor Cells

The present report proposes a more rational hyaluronic acid (HA) conjugation protocol that can be used to modify the surface of the superparamagnetic iron oxide nanoparticles (SPIONs) by covalently binding the targeting molecules (HA) with glutamic acid as a molecular linker on peripheral surface of SPIONs. The synthesis of HA-Glutamic Acid (GA)@SPIONs was included oxidization of nanoparticle’s surface with H₂O₂ followed by activation of hydroxyl group and reacting glutamic acid as an intermediate molecule demonstrating transfection of lung cancer cells. Fourier transform infrared (FTIR) and zeta-potential studies confirmed the chemical bonding between amino acid linker and polysaccharides. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay showed that HA-SPIONs-treated cells remained 82.9% ± 2.7% alive at high particle dosage (200 µg/mL iron concentration), whereas GA-SPIONs and bare SPIONs (B-SPIONs) treated cells had only 59.3% ± 13.4% and 26.5% ± 3.1% survival rate at the same conditions, respectively. Confocal microscopy analysis showed increased cellular internalization of HA-SPIONs compared to non-interacting agarose coated SPIONs (AgA-SPIONs).

Intracellular delivery of DNA and enzyme in active form using degradable carbohydrate-based nanogels

The facile encapsulation of biomolecules along with efficient formulation and storage makes nanogels ideal candidates for drug and gene delivery. So far, nanogels have not been used for the codelivery of plasmid DNA and proteins due to several limitations, including low encapsulation efficacy of biomolecule of similar charges and the size of cargo materials. In this study, temperature and pH sensitive carbohydrate-based nanogels are synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization technique and are studied in detail for their capacity to encapsulate and codeliver plasmid DNA and proteins. The temperature sensitive property of nanogels allows the facile encapsulation of biomaterials, while its acid-degradable profile allows the burst release of biomolecules in endosomes. Hence these materials are expected to serve as efficient vectors to deliver biomolecules of choice either alone or as codelivery system. The nanogels produced are relatively monodisperse and are around 30-40 nm in diameter at 37 °C. DNA condensation efficacy of the nanogels is dependent on the hydrophobic property of the core of the nanogels. The DNA-nanogel complexes are formed by the interaction of carbohydrate residues of nanogels with the DNA, and complexes are further stabilized with linear cationic glycopolymers. The DNA-nanogels complexes are also studied for their protein loading capacity. The degradation of the nanogels and the controlled release of DNA and proteins are then studied in vitro. Furthermore, the addition of a nontoxic, cationic glycopolymer to the nanogel-DNA complexes is found to improve the cellular uptake and hence to improve gene expression.

Biodegradable and nontoxic nanogels as nonviral gene delivery systems

The development of polymeric systems with tailored properties as nonviral gene carriers continues to be a challenging and exciting field of research. We report here the synthesis and characterization of biodegradable, temperature- and pH-sensitive carbohydrate-based cationic nanogels as effective gene delivery carriers to Hep G2 cells. The temperature-sensitive property of the nanogels allows their facile complexation of DNA, while the pH-sensitive property allows the degradation of nanogels followed by the release of plasmid in the endosome. The nanogels are synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) technique and are evaluated for their DNA condensation efficacy. The gene delivery efficacies of these nanogels are subsequently studied and it is found that these cationic glyconanogels can serve as potent gene delivery vectors in hepatocytes. It is found that the gene delivery efficacies of this system are similar to that of branched poly(ethyleneimine), which is used as a positive control. Moreover, these nanogels show desirable properties for systemic applications including low toxicity and degradation in acidic environment.