Can we transfect cells in tissue by using nanoparticles?

Lipid nanoparticles are used in nucleic acid (NA) delivery systems for the SARS-Cov2 vaccines (mRNA), but the approach holds promise for a therapy of variety of conditions from cancer and infectious diseases to rare inherited diseases. However, the major limiting factor to translate from vaccines to therapeutic use of nucleic acid is the efficiency of transfection in tissue. Despite the successes, even the best systems typically deliver only 1% of the genetic material (RNA or other nucleic acids (NA)) to the intended recipient cells. This is not sufficient to achieve a therapeutic effect.
Our recent project (LEAP Welcome funded) indicated that following intertumoral or intra-tissue injections, the injected mRNA-nanoparticles systems generally do not penetrate deeper into the tissue to reach cells that need to be transfected. Our previous work indicates that physicochemical properties of nanoparticles (including their 'stiffness') affect penetration of nanoparticles into in vitro cultured spheroids.
This project will assess if, and how, lipid composition of nanoparticles can be modified to influence / improve their diffusion behaviour in a cell population / tissue. The project will focus on 'helper lipids', i.e. those lipids that do not have charged / ionizable groups needed to interact with and 'condense' nucleic acids, but have a 'helping' role in a formation of lipid nanoparticles for NA delivery. The majority of current literature, and particularly patents, focuses on the structure of charged / ionizable lipids and their role in cell transfection by mRNA (https://doi.org/10.1038/s41578-021-00358-0). The optimization of lipid nanoparticles composition remains to be addressed to increase transfection of 'hard-to-transfect tissues' (https://www.nature.com/articles/s41578-021-00379-9).
The project will initially screen different helper lipids, or a combination of, to assess their potential to enhance penetration of NA-lipid nanoparticles into relevant tissue models in vitro, to establish a structure - activity relationship. The project will then include rat/mouse in vivo experiments where the local anatomy of subcutaneous, dermal, muscular tissues and draining blood and lymph play important role for nanoparticles transport and possible effects.
The project will provide training in delivery system design and physicochemical characterisation, 3D or 2D tissue culture, confocal and other microscopies, flow cytometry and animal studies.