Iron Oxide Nanoparticles Coated with a Phosphorothioate Oligonucleotide and a Cationic Peptide: Exploring Four Different Ways of Surface Functionalization

Gold nanoparticle-based probes for the colorimetric detection of Mycobacterium avium subspecies paratuberculosis DNA

Gold nanoparticle (AuNP) is considered to be the most stable metal nanoparticle having the ability to be functionalized with biomolecules. Recently, AuNP-based DNA detection methods captured the interest of researchers worldwide. Paratuberculosis or Johne's disease, a chronic gastroenteritis in ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), was found to have negative effect in the livestock industry. In this study, AuNP-based probes were evaluated for the specific and sensitive detection of MAP DNA. AuNP-based probe was produced by functionalization of AuNPs with thiol-modified oligonucleotide and was confirmed by Fourier-Transform Infrared (FTIR) spectroscopy. UV-Vis spectroscopy and Scanning Electron Microscopy (SEM) were used to characterize AuNPs. DNA detection was done by hybridization of 10 μL of DNA with 5 μL of probe at 63 °C for 10 min and addition of 3 μL salt solution. The method was specific to MAP with detection limit of 103 ng. UV-Vis and SEM showed dispersion and aggregation of the AuNPs for the positive and negative results, respectively, with no observed particle growth. This study therefore reports an AuNP-based probes which can be used for the specific and sensitive detection of MAP DNA.

Magnetic Nanoparticle Assisted Self-assembly of Cell Penetrating Peptides-Oligonucleotides Complexes for Gene Delivery

Magnetic nanoparticles (MNPs, Fe3O4) incorporated into the complexes of cell penetrating peptides (CPPs)-oligonucleotides (ONs) promoted the cell transfection for plasmid transfection, splice correction, and gene silencing efficiencies. Six types of cell penetrating peptides (CPPs; PeptFect220 (denoted PF220), PF221, PF222, PF223, PF224 and PF14) and three types of gene therapeutic agents (plasmid (pGL3), splicing correcting oligonucleotides (SCO), and small interfering RNA (siRNA) were investigated. Magnetic nanoparticles incorporated into the complexes of CPPs-pGL3, CPPs-SCO, and CPPs-siRNA showed high cell biocompatibility and efficiently transfected the investigated cells with pGL3, SCO, and siRNA, respectively. Gene transfer vectors formed among PF14, SCO, and MNPs (PF14-SCO-MNPs) showed a superior transfection efficiency (up to 4-fold) compared to the noncovalent PF14-SCO complex, which was previously reported with a higher efficiency compared to commercial vector called Lipofectamine™2000. The high transfection efficiency of the new complexes (CPPs-SCO-MNPs) may be attributed to the morphology, low cytotoxicity, and the synergistic effect of MNPs and CPPs. PF14-pDNA-MNPs is an efficient complex for in vivo gene delivery upon systemic administration. The conjugation of CPPs-ONs with inorganic magnetic nanoparticles (Fe3O4) may open new venues for selective and efficient gene therapy.

Versatility of Pyridoxal Phosphate as a Coating of Iron Oxide Nanoparticles

Pyridoxal 5'-phosphate (PLP) is the most important cofactor of vitamin B₆-dependent enzymes, which catalyses a wide range of essential body functions (e.g., metabolism) that could be exploited to specifically target highly metabolic cells, such as tumour metastatic cells. However, the use of PLP as a simultaneous coating and targeting molecule, which at once provides colloidal stability and specific biological effects has not been exploited so far. Therefore, in this work iron oxide nanoparticles (IONPs) were coated by PLP at two different pH values to tune PLP bonding (e.g., orientation) at the IONP surface. The surface study, as well as calculations, confirmed different PLP bonding to the IONP surface at these two pH values. Moreover, the obtained PLP-IONPs showed different zeta potential, hydrodynamic radius and agglomeration state, and consequently different uptake by two metastatic-prostate-cancer cell lines (LnCaP and PC3). In LnCaP cells, PLP modified the morphology of IONP-containing intracellular vesicles, while in PC3 cells PLP impacted the amount of IONPs taken up by cells. Moreover, PLP-IONPs displayed high magnetic resonance imaging (MRI) r₂ relaxivity and were not toxic for the two studied cell lines, rendering PLP promising for biomedical applications. We here report the use of PLP simultaneously as a coating and targeting molecule, directly bound to the IONP surface, with the additional high potential for MRI detection.

Chelating agents as coating molecules for iron oxide nanoparticles

Iron oxide nanoparticles coated with chelating agents with different numbers of –COOH dentates (2 to 5) behave differently.

Vectorization of Nucleic Acids for Therapeutic Approach: Tutorial Review

Oligonucleotides present a high therapeutic potential for a wide variety of diseases. However, their clinical development is limited by their degradation by nucleases and their poor blood circulation time. Depending on the administration mode and the cellular target, these macromolecules will have to cross the vascular endothelium, to diffuse through the extracellular matrix, to be transported through the cell membrane, and finally to reach the cytoplasm. To overcome these physiological barriers, many strategies have been developed. Here, we review different methods of DNA vectorization, discuss limitations and advantages of the various vectors, and provide new perspectives for future development.