Arifin, D. R., Witwer, K. W., & Bulte, J. W. M. (2022). Non‐Invasive imaging of extracellular vesicles: Quo Vaditis in vivo?. Journal of Extracellular Vesicles, 11, e12241. https://doi.org/10.1002/jev2.12241
In the second paragraph of the Introduction, the references for the capacity of extracellular vesicles derived from mesenchymal stem cells to induce vascularization and to relieve ischemia are incorrect. The correct sentence is:
Those derived from mesenchymal stem cells (MSCs), for example, were found to induce vascularization and to relieve ischemia (Gong et al. 2017; Scrimgeour et al. 2019; Wang et al. 2017).
In the legend of Figure 1, the references for EVs that have been labeled with lipophilic fluorescent dyes were incorrect. The correct sentence is:
EVs have been labeled with the lipophilic fluorescent dyes PKH26, DiI, DiD or DiR (Dabrowska et al. 2018; Garofalo et al. 2019; Lara et al. 2020; Lazaro‐Ibanez et al. 2021; Nishida‐Aoki et al. 2020; Pužar Dominkuš et al. 2018; Wan et al. 2020; Zhang et al. 2020).
In the legend of Figure 1, the PET tracer is incorrect. The correct sentence is:
The PET tracer 64Cu (Banerjee et al. 2019; Jung et al. 2020; Shi et al. 2019).
Some references in Table 2 were incorrect. Table 2 with corrected references is shown below.
In the second paragraph of the Optical imaging section, the references for the challenges associated with labeling EVs with lipophilic dyes are incorrect. The correct sentence is:
Labeling using lipophilic dyes, such as the various PKH and Di family dyes, has been reported to suffer from non‐specific transfer of the dye from labeled EVs to surrounding unlabeled cells, escape of the dye from the EV membrane, formation of EV‐mimicking micelles, and promiscuous labeling of contaminants of EV preparations (Pužar Dominkuš et al. 2018; Takov et al. 2017; Simonsen et al. 2019; Verweij et al. 2021).
We apologize for these errors.
| Imaging modality | Relative theoretical resolution | Practical resolution | Extent of testing in EV research |
|---|---|---|---|
| 1H MRI | Excellent |
Gd: 70‐80 ug Gd/g tissue in vivo. USPIO: 5 μg USPIO‐EVs (0.16 g iron) total or ∼ 8.76 × 107 USPIO‐EVs/ml (∼0.876 ng iron/ml) in vivo. FTH1: 50 μg of FTH1‐EVs total in vivo. |
In vitro characterization of physicochemical properties and protein markers, content and composition (Abello et al. 2019; Busato et al. 2016; Jc Bose et al. 2018; Jia et al. 2018; Lee et al. 2020; Liu et al. 2020; Han et al. 2021; Rayamajhi et al. 2020). Biodistribution in mice (Abello et al. 2019; Jc Bose et al. 2018; Jia et al. 2018; Han et al. 2021; Rayamajhi et al. 2020). Magnetic guidance (Lee et al. 2020) and thermal ablation (Jc Bose et al. 2018) potential were tested. Tested in tumor models (Abello et al. 2019; Jc Bose et al. 2018; Jia et al. 2018; Rayamajhi et al. 2020) and acute kidney injury (Han et al. 2021) models. |
| X‐ray/CT | Excellent | 10‐15 μg gold/g tissue in vivo. |
In vitro characterization of physicochemical properties and EV markers ( Betzer et al. 2017; Cohen et al. 2021; Lara et al. 2020; Perets et al. 2019). Biodistribution in mice (Betzer et al. 2017; Cohen et al. 2021; Perets et al. 2019). Tested in brain lesion (Betzer et al. 2017; Perets et al. 2019) and tumor (Cohen et al. 2021) models. |
| SPECT | Poor | 99mTc: 1.85‐3.7 MBq/g tissue (7.25‐16 μg 99mTc‐EVs/g tissue) in vivo. | In vitro characterization of physicochemical properties and EV markers (Banerjee et al. 2019; Faruqu et al. 2019; Hwang et al. 2015; Jung et al. 2020; Shi et al. 2019; Varga et al. 2016). |
|
PET |
111In: More than 0.035‐0.07MBq/g tissue (7×108 111In‐EVs/g tissue) in vivo. 131In: 648‐777.8 MBq total in vivo. 64Cu: 0.00148 MBq/g tissue in vivo. |
Biodistribution in mice (Banerjee et al. 2019; Faruqu et al. 2019; Hwang et al. 2015; Jung et al.2020; Lazaro‐Ibanez et al. 2021; Rashid et al. 2019; Shi et al. 2019; Varga et al. 2016). Circulation half‐life of 64Cu‐EVs (Shi et al. 2019). Tested in tumor (Faruqu et al. 2019; Rashid et al. 2019; Shi et al. 2019) and inflammation (Son et al. 2020) models. |
|
| MPI | Poor | 5 ug iron (100 μg SPIO‐EVs) in vivo. |
In vitro characterization of physicochemical properties and EV markers (Jung et al. 2018). Biodistribution in mice (Jung et al. 2018). Tested in tumor models (Jung et al. 2018). |
| Fluorescence |
Excellent for in vitro Poor for in vivo |
Not determined. |
In vitro characterization of physicochemical properties and EV markers (Pan et al. 2020; Song et al. 2020; Tayyaba et al. 2020). High resolution imaging in zebrafish embryos (Hyenne et al. 2019). Tested in tumor models (Pan et al. 2020; Song et al. 2020). Ce6‐induced cell apoptosis under irradiation (Pan et al. 2020). |
| BLI | Poor | 3.6 μg Gaussia luc‐EVs. |
Biodistribution in mice (Lai et al. 2014; Lazaro‐ Ibanez et al. 2021; Toribio et al. 2019). Circulation half‐life of Gaussia luc‐EVs (Lai et al. 2014). |
| BRET | Poor | Not determined. |
Up to date, BRET‐based approach is the only model for tracking endogeneously secreted EVs (Hikita et al. 2020). Biodistribution in mice (Hikita et al. 2020). Tested in tumor models (Hikita et al. 2020). |