Diverse Ways of Delivering Desired Substances into Cells

 by Christine Z

Delivery of desired substances into cells is a fundamental aspect of several biological applications, such as gene therapy, drug delivery, RNA interference and so on. Among them, substances like proteins and manually synthesised drugs, DNAs and RNAs need to be delivered into cytoplasm, organelles and nuclei to function. There are several delivery methods, including virus, lipid, polymers, and electricity. 

One of the most well-established methods for delivering genetic material into the nuclei is through the use of viral vectors. Viruses have the nature to inject their genetic material into cell nuclei and join them to the cell’s DNA, thus making them be transcribed into mRNA and translated into proteins, therefore new viruses can be made. This aspect utilises this nature to deliver desired DNA into the nucleus, therefore gene editing or gene therapy can process. The choice of vector depends on factors such as the type of cells to be targeted, the size of the DNA, and considerations about safety. Once the type of virus is chosen, the gene of interest is inserted into the viral genome by restriction enzyme digestion, PCR and ligation. The deletion of virulence genes is also crucial for the safety of the receiver.

Lipid nanoparticles, polymer nanoparticles and electric shock are the other three common methods of delivering. Lipid nanoparticles can encapsulate drugs or nucleic acids within their lipid bilayers and can be delivered into cells via endocytosis or passive diffusion. Lipid nanoparticles can be made from dissolving lipids and chemicals in an organic solvent such as ethanol, followed by the removal of the solvent to form lipid nanoparticles around the chemicals. To use polymer delivery systems, selecting a suitable polymer is the first step, which is based on the hydrophobicity, molecular weight and stability of the substance to be delivered. The delivery systems can be prepared using solvent extraction, nanoprecipitation and electrospinning. Solvent extraction is the same as the one mentioned in making lipid nanoparticles. Nanoprecipitation involves mixing a solution of the polymer and the substance with a non-solvent that is miscible with the solvent dissolving the polymer. The rapid diffusion of the non-solvent into the polymer solution leads to the precipitation of polymer nanoparticles. Electrospinning is a technique used to prepare polymer fibres surrounding the substance to be delivered. Electricity shock can also help with delivery into cells. The electrical pulses create disruptions in the cell membrane, temporarily increasing its permeability, allowing the charged molecules, ions, and small particles in the surrounding buffer to cross the membrane.

These methods have their respective advantages and disadvantages. For example, they might be efficient, specific and biocompatible, but at the same time toxic, having possibilities to cause immune responses and lead to irreversible damage to the body. Overall, delivery systems are important in delivering substances into cells, each with its advantages and disadvantages. The choices of method should be based on specific requirements and safety considerations.