Exosome-based delivery system has ideal advantages, making it a superior choice, such as specificity, stability, long circulating half-life and biocompatibility with minimal toxicity to target tissue. At present, Creative Biolabs has successfully realized the loading of cargos into exosomes by using the pre-loading strategy.

Introduction of Pre-loading Strategy

Loading cargo into exosomes requires bypassing the barrier of the outer membrane. Synthetic carriers such as liposomes can be loaded with cargos during the synthesis process. Similarly, exosomes can be pre-loaded in situ by adding exogenous drugs to parental cells. Co-expressed proteins in parental cells can also be guided into exosomes through designed protein-protein interactions. In the pre-loading technique, the exosomes are loaded with cargos indirectly, that is to say, the parental cells are incubated with cargos at room temperature, and the selected proteins or drugs can be loaded in advance. When the cells release exosomes, these vesicles will be loaded with cargos. This strategy is particularly conducive to the loading and delivery of oligonucleotides.

Fig.1 Exosome generation, secretion and cargo transfer from the donor cells to the recipient cells. (Luan, 2017)

Pre-loading Strategy Service for Load Cargo into Exosomes

Due to the availability of various cellular engineering methods, most of the modification of exosomes has been performed on parental cells, which are then cultured to secrete the modified exosomes. Possible pre-loading strategies include:

• transfecting/infecting parental cells with DNA encoding therapeutically active compounds and then releasing them via exosomes;
• directly loading parental cells with drugs and then releasing them in exosomes, mainly used in small molecule chemical drugs with low cytotoxicity.

Protein sequences and different types of RNA are commonly used for cell transfection, ultimately altering the phenotype of the released exosomes. Genetic engineering strategies may require the use of lipid methods (i.e., via Lipofectamine) to load cargo or produce the desired gene expression. By changing the synthesis of exosomes, people can control the therapeutic cargo they carry.

Fig.2 Exosomes can be modified by manipulating progenitor cells. (Xu, 2020)

Technical Advantages

• The output of exosomes is controllable. This pre-loading strategy is suitable for the types of projects that require downstream animal experiments;
• We can provide the services of cell culture and stable cell line construction, providing the prerequisite for mass production of exosomes loaded with cargos;
• No damage to exosome structure.

Exosomes can transfer encapsulated proteins and genetic information to recipient cells and act as information transmitters between cells. Creative Biolabs has successfully established the pre-loading strategy to efficiently load exogenous cargos into exosomes. If you are interested in our services, please contact us to discuss your specific project requirements.

References

1. Luan, X., et al. Engineering exosomes as refined biological nanoplatforms for drug delivery. Acta Pharmacologica Sinica. 2017, 38(6): 754-763.
2. Xu, M., et al. Recent advancements in the loading and modification of therapeutic exosomes. Frontiers in bioengineering and biotechnology. 2020, 8.

• Exosome Cargo Post-loading