Engineered Exosomes–Drug Loading

CD Bioparticles is a leading manufacturer and supplier of various drug delivery products and services. Utilizing CD Bioparticles' cutting-edge manufacturing platform for extracellular vesicles, we specialize in EV-based therapies, particularly those utilizing exosomes as carriers. Our comprehensive services extend to enhancing exosome production, characterizing, purifying, and conducting potency assays.

Introduction of Drug Loading

Three main elements make up an EVs-based delivery system: vesicles, cargoes, and surface decorations1.

Exosomes can load cargos endogenously during theirbiogenesisorexogenouslyafter isolation of EVs. The cargos that have already been used are drugs, proteins, nucleic acids, or nanomaterials. The strategy to load can be direct or indirect.2

Exosome drug loading type.Figure 1. Exosome drug loading type.

A. Indirect loading

An indirect method means to load the cargo into a donor cell which will release exosomes containing the cargos.

  • Transfection of parental cells with nucleic acids, Reagent transfection, Expression plasmids, Nanoporation and Self-directed EPN biogenesis.
  • Incubation of parental cells with therapeutic compound.
  • Viral vector.

B. Direct loading

A direct loading is a non-cell-based approach where the molecule is directly load into the exosomes. Direct loading includes both active and passive loading.

  • Active loading: EVs are simply incubated with molecules that passively diffuse through the EV membrane in a concentration-dependent manner.
  • Passive loading: Sonication, Electroportation, Extrusion, Freeze–thaw techniques and Incubation.

The Specific Features of Different Drug Loading Methods

Here we listed the pros and cons of different loading methods for customers' reference.

Table 1: Pros and cons of drug encapsulation methods

Loading strategy Pros Cons Payloads
Transfection with nucleic acids Simple; No harm to EV structure Low efficiency; Payloads degradation siRNAs; miRNAs
High loading efficiency;
Independent of cell sources or transfected vector
Induces cellular stress mRNA
Cytoplasmic delivery of macromolecular cargos could induce an immune response Protein nanocages
Direct incubation with therapeutic compounds Efficient Alteration in EV size Hydrophobic and hydrophilic
Quick and simple; No harm to EV structure Low efficiency; Relatively hydrophobic compounds PTX、DOX、methotrexate、CIS、Curcumin、cucurbitacin-IHydrophobically modified siRNAs
Infection with viruses Low immunogenicity; High transduction efficiency; Low off- target cytotoxicity Induction of genotoxicity Viral therapeutics/AAVs
Sonication Relatively high efficiency;
hydrophilic and hydrophobic molecules
Integrity, size disruption; EV aggregation; Payloads aggregation or degradation PTX; DOX; Catalase
Electroporation Loading with hydrophilic and
hydrophobic molecules
EV aggregation, EV integrity
Extrusion Relatively high efficiency;
hydrophilic and hydrophobic molecules;
Low cytotoxicity
Alteration in EV size; EV aggregation Catalase; Porphyrins
Freeze-thaw cycle Quick and simple Low efficiency; Alteration in EV size; EV aggregation; Payloads inactivation Catalase; Protein
Incubation Relatively high efficiency Immunogenicity;
Saponin concentration control and washing required
Catalase; Porphyrins; DOX

Our Drug Loading EV Featured Services:

CD Bioparticles specializes in the development of drug delivery systems and customization of exosomes for efficient drug delivery. We utilize our advanced technologies to provide suitable and efficient encapsulation methods based on the unique characteristics of your cargo. By doing so, we can shorten the encapsulation processing time, enhance encapsulation efficiency, and maintain a stable exosome structure.


  • Incubation or passive loading
  • Surfactant treatment
  • Dialysis
  • Freeze-thaw treatment
  • Sonication
  • Electroporation
  • Extrusion

Loading Assessment

Concerning the loading, it is necessary to be particularly precise on the readout method. Actually, many studies in the literature did not distinguish whether the cargo is loaded inside in the EVs, embedded in the membrane or stuck on the surface of the EV.

At CD Bioparticles, we employ our preferred methods to achieve accurate payload assessment. The quantitative methods we utilize enable us to calculate the actual loading capacity of EVs (i.e., the number of molecules loaded per vesicle) and the loading efficiency (i.e., the percentage of loaded cargo relative to the total amount of cargo to be loaded in the process).

Analysis and Characterization

Encapsulation efficiency, loading capacity, positivity rate, size analysis (NTA, TEM), biochemical analysis, (Exoview, MACSPlex…), omic analysis, dosages (proteins, DNA, RNA, Lipids…), surface-markers…

Quotations and Ordering

Quotations and Ordering


  1. Rezakhani, L., et al.; Exosomes: special nano-therapeutic carrier for cancers, overview on anticancer drugs. Med Oncol. 2023, 40, 31.
  2. Jayasinghe MK, T et al.; New approaches in extracellular vesicle engineering for improving the efficacy of anti-cancer therapies. Semin Cancer Biol. 2021, 74:62-78.
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