Palin Narsian, Biological Sciences, Fall 2020
‘This image depicts a standard liposome, which scientists hope may act as a more efficient delivery system for CRISPR.
Source: Wikimedia Commons
In recent years, the field of genetic engineering has been transformed by CRISPR, a genome-editing tool. Before CRISPR, gene editing was a grueling and time-consuming process that usually resulted in failure; with CRISPR, scientists are able to alter the DNA of various organisms in a time-efficient and effective manner, opening the door to countless biological innovations (“Science Daily,” 2020). This being said, there are still problems associated with CRISPR that diminish its effectiveness. One such concern is the delivery system—as it stands, the CRISPR payload is typically loaded into a viral vector that moves throughout the body to find desired cells (Crawford, 2017). Using viral vectors as the delivery system can result in other physiological effects such as an adverse immune response and toxicity to the body (Crawford, 2017).
Recently, a team of biomedical engineers from the University of New South Wales found that liposomes could serve as a viable replacement for the current viral delivery system. Liposomes are phospholipid vesicles that consist of one or more concentric lipid bilayers enclosing discrete aqueous spaces (Sercombe et al., 2015). This large aqueous (water-filled) center coupled with its biocompatible lipid exterior makes for an efficient delivery system. In fact, Dr. Wei Deng notes that “Liposomes are already well established as an extremely effective drug-delivery system” (Crawford, 2017). When encapsulated within liposomes, molecules are sheltered from harmful effects such as dilution, early activation, and degradation. Liposomes themselves are considered pharmacologically inactive with minimal toxicity due to their structure, solving a key problem of the virus-based delivery system. Dr. Deng goes on to explain that liposomes are easy to prepare and administer, which increases their attractiveness further (Crawford, 2017).
The method of CRISPR release from liposomes must also be considered when assessing liposomes as a possible replacement for the current delivery system. The New Wales Team was able to address this issue as well. As Dr. Deng explains, “when light is shone onto the liposomes they can be disrupted at once, immediately releasing the entire payload” (Crawford, 2017). With this finding, the team is able to make sure that CRISPR finds the right gene at the tight time. One limitation, however, is that traditional light is only able to reach a centimeter below the skin. The team believes this issue can be circumvented through the use of X-rays, which are likely to achieve the same effect. Although an exciting advance in the already exciting field, further studies must be completed to determine the clinical viability of liposomal delivery.
Dr. Deng and her team are excited to conduct this further research and prove that X-rays can help deliver CRISPR to cells in a variety of different applications, including administering gene therapy to cancer patients as a replacement for chemotherapy. As opposed to chemotherapy, which is largely non-specific and has severe side effects due to its destruction of healthy cells in addition to cancerous ones, this new targeted technique would be far more specific and induce far fewer side effects (Crawford, 2017). Overall, the liposomal delivery system has the potential to revolutionize the use of CRISPR, increasing its usefulness and application, inevitably leading to new innovations in the landscape of genetic engineering.
References
- Crawford, M. (2017, May 31). 8 Ways CRISPR-Cas9 Can Change the World. The American Society of Mechanical Engineers. Retrieved from: https://www.asme.org/topics-resources/content/8-ways-crisprcas9-can-change-world
- Science Daily. (2020, November 12). Researchers show safer, more targeted way to deliver CRISPR gene therapy.Retrieved from: https://www.sciencedaily.com/releases/2020/11/201112093112.htm
- Sercombe, L., Veerati, T., Moheimani, F., Wu, S. Y., Sood, A. K., & Hua, S. (2015, December 01). Advances and Challenges of Liposome Assisted Drug Delivery. Pharmacol 6(286). Retrieved from:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4664963/
Good article