Non-viral vectors based on nanotechnology are a novel piece of research for use as carriers in order to replace conventional viral vectors within the delivery of the CRISPR-Cas9 system. This research has been covered in a review, published in the journal, Chemical Engineering, with hopes of advancing this gene-editing tool in the treatment of disease.
Study: Non-viral nanocarriers for CRISPR-Cas9 gene editing system delivery. Image Credit: elenabsl/Shutterstock.com
Clustered regularly interspaced short palindromic repeat-associated protein 9 (CRISPR-Cas9) is considered to be a revolutionary gene-editing tool that can be used to treat diseases. It can be used to modify genetic defects permanently and ensure healthy functioning is re-established.
This is based on an adaptive prokaryotic immune system that prevents bacteria and archaea from being invaded by viruses and has advanced into a powerful genomic editing method that can be used to manipulate the genetic information of plants and animals.
Benefits of this genome editing system consist of being simple, versatile and more effective than other early gene-editing tools, such as zinc-finger nucleases and transcription activator-like effectors nucleases.
The potential of CRISPR-Cas9 is momentous due to being able to theoretically edit any gene sequence and thus correct faulty gene mutations and cure diseases.
Challenges with Delivery
The current delivery systems for CRISPR-Cas9 rely predominantly on physical methods, viral vectors as well as a commercial cationic lipid. However, the challenge of this powerful disease-preventing strategy consists of delivery limitations such as instability and cell impermeability being found in vivo.
The physical methods comprise electroporation, microinjection, and microfluidics, however, with drawbacks including difficulties with in vivo application, due to the challenge of targeting deep tissue without damaging surrounding tissue, it can be an inefficient method to delivering the CRISPR system into multiple cells through single microinjection.
Additionally, while the microfluid method can be seen as having the most cell viability, it is still not as efficient as required. However, the use of viral vectors, such as adenoviral vectors, adeno-associated viruses and lentiviral vectors for delivering CRISPR can be seen as being more effective, with advantages such as high internalization efficiency and wide host range.
The drawbacks of these viral vectors, while effective, consist of activating the immune response with long-term exposure and this can cause adverse effects within the body.
Benefits of Nanocarriers
The advancement in nanotechnology has introduced a novel and promising concept of using non-viral nanocarriers for the delivery of the CRISPR-Cas9 system. The use of nanoparticle-based delivery vehicles that can be modified to target specific tissue has provided a promising solution for the delivery challenges conventional strategies have faced.
The benefit of using nanocarriers includes being within the nanoscale of 1 and 100 nm in size, which allows natural interaction with biological systems, as well as controlling the release of the cargo it is carrying, shortening the exposure time of the RNA/protein to the nuclease/protease enzymes which would reduce degradation and ensure the preservation of their activity.
Additionally, the use of this nanotechnological carrier also ensures low immunogenicity and cytotoxicity, which potentiates its use for large-scale clinical applications.
Non-Viral Nanocarriers for Enhanced CRISPR Delivery
The inclusion of a non-viral nanocarrier for the CRISPR-Cas9 gene-editing system further advances the field of medicine as a precision gene therapy method, which is safe and effective for patients.
Examples of non-viral nanocarriers for this powerful therapeutic tool consist of lipid or lipid-like nanocarriers, protein/peptide nanoparticles, polymer-based nanoparticles such as chitosan, and even metallic-based nanoparticles such as gold nanoparticles.
These nanocarriers have a high packaging property and targeting ability as well as allowing surface functionalization.
Lipid or lipid-like nanoparticles have been found to be a good vector for delivering CRISPR-Cas9 compared to other synthetic materials due to being biologically safe, without cytotoxicity and having good interaction with native tissue.
Additionally, the key component of lipid/lipid-like nanocarriers includes a cationic ionizable lipid which is critical for efficient gene encapsulation, cellular internalization, and endosomal release.
With an ability to functionalize these versatile particles, such as bio-reducible and bio-degradable lipids, as well as having the benefit of charge and length of alkyl groups, this method of delivering CRISPR-Cas9 may prove to be highly effective in vivo.
Other methods can also prove to be effective, such as polymer-based nanocarriers, as this delivery strategy can deliver all three modes of the CRISPR-Cas9 system, such as Cas9/sgRNA plasmid DNA, Cas9 mRNA/sgRNA, and Cas9 protein/sgRNA.
With polymers being easily modified and having effective functionality, as well as easy uptake, high drug-loading and enhanced targeting ability, the use of polymers such as chitosan, would be an effective delivery method for CRISPR systems.
Future Therapeutic Outlook
With mutations playing a significant role in the lives of every person, the gene-editing tool, CRISPR-Cas9 would be a revolutionary method of permanently correcting mutations.
This would be significant for both somatic and germline mutations, in order to ensure genetic disorders, as well as cancers, are able to be genetically edited – saving both the burden and trauma of patients experiencing various stages of diseases.
This revolutionary therapeutic tool would increase the quality of life of patients and also alleviate the financial burdens of healthcare systems that spend money on treatments and drugs, which can be resistant to the disease of patients and further cause them trauma.
The advancement in nanotechnology and the use of nanocarriers may advance the delivery strategy of CRISPR-Cas9 and solve obstacles being faced with in vivo delivery, and this will ultimately innovate the field of medicine and personalized medicine.
Tang, X., Wang, Z., Zhang, Y., Mu, W. and Han, X., (2022) Non-viral nanocarriers for CRISPR-Cas9 gene editing system delivery. Chemical Engineering Journal, 435, p.135116. Available at: https://www.sciencedirect.com/science/article/pii/S1385894722006210
Din, F., Aman, W., Ullah, I., Qureshi, O., Mustapha, O., Shafique, S. and Zeb, A., (2017) Effective use of nanocarriers as drug delivery systems for the treatment of selected tumors. International Journal of Nanomedicine, Volume 12, pp.7291-7309. Available at: https://doi.org/10.2147/IJN.S146315