Table 6.
Summarizes the most common delivery approaches that can be used for both in vivo and in vitro CRISPR/Cas system delivery
| Delivery methods | Carrying capacity | Toxicity | Biosafety level | Advantages | Challenges | Strategies | References |
|---|---|---|---|---|---|---|---|
| Adenovirus | 38 kb | High | BSL-2 |
The host genome disruption risk is low Having trouble transducing certain cell types |
High immunogenicity | Targeting immune privilege orangs | [215, 216] |
| AAV in vitro | 4.7 kb | Very low | BSL-1 |
Animal models with long-term transgenic expression AAV has not been linked to any diseases in humans Very low immunogenicity |
Limited size capacity Preexisting immunity to natural serotypes Exposes constantly for a long time after injection Hepatotoxicity |
Splicing the Cas protein into two vector Targeting infant and immune privilege organs Using anti-Cas proteins |
[88] |
| Retrovirus | 8 kb | Low | BSL-2+ |
Ability to transform their single-stranded RNA genome into a double stranded DNA molecule Ability to stably integrate into the target cell genome |
– | – | [119] |
| Lentiviral vector | 8 kb | Moderate | BSL-2+ |
Large genetic capacity Ability to transduce both dividing and non-dividing cells |
De novo protein expression may cause immunological responses that result in the removal of transduced cells and the production of antibodies that block the action of released factors | Tacrolimus, cyclophosphamide, and cyclosporine can stop the production and release of cytokines as well as the activation and expansion of T cells | [78] |
| Baculovirus | 38 kb | Very low | BSL-1 |
Flexible enough to contain many genes or big inserts By infecting insect cells, recombinant baculoviruses can easily be created and yield high titers |
– | – | [217, 218] |
| Electroporation | 15 kb | Very low | BSL-2 |
Takes less time and cost Used in in vivo, in vitro, and ex vivo research |
Limited experiences in vivo | – | [219, 220] |
| Microinjection | No size limitation | – | BSL-1 |
Successful approach to inject macromolecules into embryos Guaranty of delivery to the targeted cell |
Time consuming Require skill and facilities Performed generally in vitro |
A high level of sophistication and physical skills are needed to reduce cell damage | [87, 221] |
| Inorganic compound-based nanoparticle | – | Very low | BSL-1 |
Non immunogenic Low cytotoxicity High packaging capacity |
Delivery efficiency is low | – | [222] |
| Polymeric delivery system | – | Very low | BSL-1 |
Non immunogenic Transient expression High packaging capacity |
Cytotoxicity In vivo efficacy is low |
– | [222] |
AAV adeno-associated virus, Cas CRISPR-associated protein