The use of gene editing technology to change human genes to enhance self-healing ability is a very challenging idea that involves many complex issues. At present, there are many limitations in terms of technology and ethics. The following are some related discussions.： ### Technical route 1. **Selection of gene editing tools** -**CRISPR-Cas9 system**: This is currently the most widely used gene editing technology. -First, the target gene related to self-healing ability needs to be identified. For example, studies have found that certain genes play a key role in the signaling pathway of cell damage repair, such as some genes involved in DNA damage repair (such as BRCA1, BRCA2, etc.). -Design a guide RNA (gRNA) for the target gene so that it can complement and pair with a specific region of the target gene. -Introduce gRNA into the cell together with Cas9 nuclease. Under the guidance of gRNA, Cas9 recognizes and cleaves specific sequences of target genes, causing DNA double-strand breaks. -The cell's own DNA repair mechanism repairs the fracture through homologous recombination (HR) or non-homologous terminal connection (NHEJ) pathways. If homologous recombination is used, a designed donor DNA template with an optimized sequence can be provided to guide the cells to repair the gene according to the template, so as to achieve precise editing of the target gene, so that its function can be enhanced or changed, in order to improve self-healing ability. -**Other gene editing technologies**: Such as zinc finger nuclease (ZFN) technology and transcription activation-like effector factor nuclease (TALEN) technology. -ZFN technology specifically recognizes and binds the target DNA sequence through the artificially designed zinc finger protein domain, and then fuses the nuclease domain to cleave the DNA. The principle is similar to CRISPR-Cas9, which also uses the cell's DNA repair mechanism to achieve gene editing. Design a zinc finger protein with specific DNA binding specificity, connect it to the nuclease domain, and construct it into a ZFN expression vector. After the vector is introduced into the cell, ZFN will cut DNA at the target gene, and then perform gene editing through the cell's own repair mechanism. -TALEN technology is a nuclease technology based on transcriptional activation-like effector (TALE). The AMINO ACID sequence of the TALE protein has a constant correspondence with the base sequence of the target DNA, and different DNA sequences can be identified by designing different TALE repeats. The TALE is fused with the NUCLEASE FokI to form A TALEN expression vector. After BEING introduced into the cell, TALEN will cut DNA at the target gene site, and then use the CELL's DNA repair system for GENE editing to achieve the purpose of gene editing related to enhancing self-healing ability. 2. **Gene introduction and delivery** -** Virus vector**： - Commonly used are lentiviral vectors, adenovirus vectors, etc. For example, lentiviral vectors can stably integrate edited genes into the host cell genome. -Construct a viral vector carrying the target edited gene and package it into infectious virus particles. -Introduce genes into human cells by way of viral infection. For example, a viral vector can be injected into a specific tissue or organ to infect the corresponding cells, thereby achieving the delivery of the target gene. However, viral vectors may have risks such as immune response and insertion mutations. -** Non-viral vector**： -Such as liposomal nano-particles. Liposomes are bimolecular vesicle structures formed by phospholipids, which can wrap nucleic acid molecules such as DNA. -The edited genes are mixed with liposomes to form nano-particles, which are delivered into the body by intravenous injection, etc. Liposomal nano-particles have good biocompatibility and low immunogenicity, but the efficiency of gene delivery may be lower than that of viral vectors. ###Challenges and limitations 1. **Technical level** -**Off-target effect**: Gene editing techniques may cause cleavage at non-target sites, leading to unexpected gene mutations. This may cause a series of unknown biological consequences, such as activating carcinogenic genes and affecting normal gene expression regulatory networks, which seriously threaten human health. -**Gene regulation complexity**: Gene expression and function are affected by complex regulatory networks. Just changing one gene may not fully enhance the ability to repair itself, because cell self-repair is a process that involves the synergy of multiple genes and signaling pathways. Moreover, the effect of gene editing may be affected by various factors such as cell type and physiological state, making it difficult to accurately predict and control. -**Delivery efficiency and safety**: Accurately delivering editing tools and genes to specific cell populations in the body and ensuring their safety is a major problem. For example, viral vectors may trigger an immune response, and the delivery efficiency of non-viral vectors needs to be improved. How to balance delivery efficiency and safety is a key issue that needs to be continuously optimized. 2. **Ethical and social dimensions** -**Germ line gene editing**: If you try to change the genes of human germ cells through gene editing, it will cause serious ethical disputes. This may lead to the “design of the baby”