Table 4 Delivery methods for transferring synthetic regulatory RNAs to bacteria
Delivery methods | Traits |
|---|---|
Biological methods | |
 Transduction | A specific DNA donor is required for DNA transfer to recipient bacteria |
 Conjugation | Requiring physical contact of recipient and donor (host strain) with a conjugative plasmid or participation of a third bacterium with a helper plasmid |
Not useful for large-scale delivery applications | |
 Gene transformation | Limited to a few naturally competent groups |
Physical methods | |
 Electroporation | Highly efficient but requires low ionic strength medium and high voltage |
Not useful for large-scale delivery applications | |
 Laser irradiation | Employs a laser to change cell permeability to allow transferal; requires physical contact of laser and cells |
 Ultrasound DNA delivery (UDD); Sonoporation | Appropriate approach for plasmid or DNA fragment transferal to eukaryotic cells (e.g., gene therapy) |
 Heat shock transfer | Mostly used for E. coli (in parallel with the calcium phosphate method) |
Chemical methods | |
 Protein & Peptides | Introduced in the late 1950s, this technique originally used high salt concentration and polycationic proteins to enhance nucleic acid entry into the cell. |
Now cationic peptides are using to enhance nucleic acid delivery. Cationic peptides have been found useful for enhancing cellular uptake and/or cell targeting oligonucleotide analogs. These peptides are synthetically conjugated, used as non-covalent complexes, or used in combination with polymer formulation techniques | |
 Calcium phosphate | Simple, effective and still widely used for nucleic acid delivery |
 Artificial lipids | DNA has been successfully complexed with cationic, anionic and neutral liposomes. These complexes can be handled easily, but lipid-based systems generally have significant drawbacks, including the lack of targeting and variations arising during fabrication |
 Naonparticles | Using carbon nanotubes, nucleic acid is delivered into cells. Magneto-transformation has also been used for nucleic acid transfer, but in that method, pulsed magnetic fields assisted the delivery of DNA using magnetic nanoparticles. |