The application and development prospects of non-viral vectors in gene editing.

The help of a vector is required to deliver CRISPR-Cas9 to cells.
virus vector is currently the most popular delivery method, but its high cost, the existence of off-target effect, but also the human body will produce cancer risk.
and this time the latest work of the Research Team at Zhejiang University opens another window into the use of non-viral vectors in gene editing.
pinpoint and cut off genetic sites in DNA, turn off a gene or introduce new gene fragments, and restore the possibility of a hopeless patient being cured... CRISPR gene editing technology has been known as "God's scalpel" since its inception.
but when this magical "surgical knife" is actually lost, its off-target effect has been one of the key obstacles to its application.
recently, researchers from Nanjing University, Xiamen University and Nanjing University of Technology have developed a new carrier of "gene scissors" tools that can be controlled by gene editing and have broad application prospects in the treatment of major diseases such as cancer.
the results have been published in a new issue of the American journal Scientific Advances.
genetically modified soybean oil, insect-resistant cotton, and even gene-editing babies from viral vectors... Despite the controversy, gene editing, as a product of a new era, has quickly made contact with most ordinary people in just a few decades.
but when it comes to the tools and principles used, many people are not familiar with it.
since the secrets of the genetic code were revealed in the 1960s, human attempts to modify the genes have never stopped.
, in a more visual way, gene editing can be understood as the process of using "gene scissors" to disconnect the DNA chain and modify the target DNA fragments, whether to add or knock out genes, is essentially changing the characteristics of a creature from a molecular level.
, the most commonly used "gene scissors" by scientists today is an external DNA called CRISPR-Cas9, which is born without bacteria.
viruses to their own reproduction using bacterial cell tools for their own gene replication services, bacteria in the fight against the virus, in the body evolved crispR system, can quietly remove the virus gene from their own chromosomes.
scientists have used this feature to develop this cutting-edge "gene scissors." How
send CRISPR-Cas9 to cells? This requires the help of the carrier.
according to the source of gene vector, we can divide the gene vector into five categories, namely plasmid vector, phage vector, virus vector, non-viral vector and micro-ring DNA.
virus vector shipping is by far the most popular delivery method, with more than 70 percent of gene drug vectors in clinical trials as of June 2018.
the compound is connected to the virus, the virus invades the cell nucleus of the target cell, CRISPR-Cas9 this "gene scissors" can play a real role.
retroviruses, adenoviruses and adenoviruses (AAVs), these three types of viruses, have been widely used in the provision of the treatment of genetic material.
however, building a virus vector is a difficult and costly process, and using these virus vector deliveries is not foolproof.
"CRISPR-Cas9's advantages are obvious, and the disadvantages are obvious.
it has off-target effects, it may cut off areas other than the target, and when the normal area is cut off, it can cause significant damage.
" said Song Yujun, a professor at Nanjing University's School of Modern Engineering and Applied Sciences.
studies have shown that viral vectors have inherent drawbacks in the CRISPR-Cas9 system, including the risk of cancer, insertion size limits, and immune responses in the human body.
, for example, retroviruses can cause an inserted mutation that can lead to cancer, and high-dose injections of AVA in the veins for gene therapy can also be severely toxic.
safer gene-editing vectors, the safety of viruses used as transport vectors for genetic engineering is not fully controlled, so scientists have proposed several alternative non-viral delivery materials, including gold nanoparticles, black phosphorus, metal organic skeletons, graphene oxide, and various nanomaterials.
compared to viruses, these materials are a great improvement in safety.
however, the timing of gene editing and the process of gene editing are still beyond the control of scientists.
the latest scientific research published in the journal Science Progress, researchers from Nanjing University, Xiamen University and Nanjing University of Technology have developed a new non-viral vector of "gene scissors" tools that can control "pruning" genes through near-infrared light to achieve controlled gene editing in time and space in the body, and have broad application prospects in the treatment of major diseases such as cancer.
targeting the off-target effect of CRISPR-Cas9, the research and development team, after a year-and-a-half of experimentation, developed a non-viral vector called "upper-converted nanoparticles", which can be swallowed in large quantities by cells and locked crispR-Cas9 on upper-converted nanoparticles through a photosensitive compound. "Infrared light has a powerful tissue penetration, which provides the possibility of safe and precise application of gene editing technology in deep tissues in the human body," said Song Yujun,
.
" the trigger for the experiment is two types of light - near-infrared light and ultraviolet light.
near-infrared light and ultraviolet light have a special nature, the former can penetrate human tissue to reach the target position, the latter can achieve the cutting off photosensitive molecules.
exposed to near-infrared light, these nanoparticles absorb low-energy near-infrared radiation and convert it into visible ultraviolet light, can automatically open the "lock" between nanoparticles and Cas9 protein, so that Cas9 protein into the nucleus, so as to achieve the target gene accurate knockout, induced tumor apoptosis.
the team verified the effectiveness of the system from various angles, such as genes, proteins and cells, and in the course of treatment of the mice, the team found that only the tumors of the near-infrared light exposure experimental group were effectively suppressed, and from the size of the tumors removed after 20 days, the tumors in the experimental group were much smaller than those in the control group.
the technology opens another door to the use of non-viral vectors in genetic engineering.
once the technology can be clinicalin in the future, tumors, especially solid tumors, can achieve noninvasive treatment, Parkinson's disease, diabetes and other patients can also benefit from this technology.
non-viral vector is widely used in clinical clinic, but its safety uncertainty, high preparation and transportation costs restrict its promotion in genetic engineering. As a result, non-viral vectors are attracting more and more attention from researchers
.
"At present, non-viral vectors of various nanomaterials are being done by researchers, such as biodegradable biopolymer materials, and its prospects are very large."
," Song Yujun told reporters.
research on non-viral vectors has two directions, one is the organic material gene delivery system, the other is the non-polar material gene delivery system.
In the field of organic materials research, lipids, polyethylene amines and their derivatives, cation polypeptides, tree molecules and their derivatives, shell polysaccharides and their derivatives, polyurethane, cyclodextrin and its derivatives are the main directions for scientists to study.
non-viral lipid nanoparticles designed by various lipids are easy to prepare, the immune response is not intense, and has a larger effective load, so it has been widely used in clinical practice, such as vaccines and gene drug delivery, cancer treatment, tumor imaging, etc. will use this transmitter.
delivery systems with polyethylene amine and its derivatives as carriers have also been used in clinical trials of multiple diseases, including ovarian cancer, pancreatic cancer, primary peritoneal malignancies, multiple myeloma, etc.
the research of other delivery materials has not entered the clinical stage.
is easier to control humanly than organic materials, and its dimensions are adjustable and the surface is easy to modify.
gold nanoparticles, carbon nanotubes, graphene, upper conversion nanoparticles and other materials have been extensively studied, the mainstream delivery methods include negative-electric genes and positive inorganic nanoparticles to form a compound, genes in the form of responsive covalent bonds connected to nanoparticles or inorganic nanoparticle surface modification of the two parental polymers, negative charge gene through electrostatic action adsorption in the polymer layer.
Song Yujun's team developed a new technology for light manipulation gene editing.
at present, the study of inorganic delivery materials is still in the laboratory stage, the clinical stage of the trial has not been approved, the impact on the body has not been conclusive.
"inorganic nanoparticles contain non-essential elements of the human body and may therefore have some side effects.
when we experimented, we observed the mouse plane for a relatively short period of time, as little as a few weeks or more than a few months, and no major effects were found at the cellular and animal levels.
if it can find the right, safe, inorganic material with the same function, its future will be unlimited.
" Song Yujun is full of confidence in the future of non-viral vectors.
Source: Science Daily.