Regenerative Medicine
Amid Yazdani, MD
Post-doctoral research fellow
Johns Hopkins School of Medicine
Baltimore, Maryland, United States
Mirza Farhana Iqbal Chowdhury, MD
Post-doctoral research fellow
Johns Hopkins School of Medicine
Baltimore, Maryland, United States
Farzad Mokhtari-Esbuie, MD
Post-doctoral research fellow
Johns Hopkins School of Medicine
baltimore, Maryland, United States
Louis J. Born, MD
Resident Physician
University Of Maryland
baltimore, Maryland, United States
John W Harmon, MD FACS
Professor of Surgery
Johns Hopkins Hospital
baltimore, Maryland, United States
Amid Yazdani, MD
Post-doctoral research fellow
Johns Hopkins School of Medicine
Baltimore, Maryland, United States
Initially, conditioned media were collected, and EVs were isolated. After constructing 3D GelMA hydrogels, to assess MSC EV bioactivity, GelMA bioink was made by suspending 8.84 μg EVs/μl in 7% GelMA in phosphate-buffered saline (PBS) with either 0.1%, 0.2% lithium phenyl-2,−4,6-trimethylbenzoylphosphinate (LAP), resulting in 500 μg of EVs per GelMA disc with a 6 mm diameter and 2 mm thickness. Successfully printed constructs were placed in 1.7 ml of PBS, and samples were collected at the indicated time points to assess EV release.
Results: Gel crosslinked with 0.1% LAP displayed a significant burst release, while the release from 0.2% LAP crosslinked gels were more prolonged over the first 3 days. In both cases, the release was essentially complete by 14 days
Bioactivity of EVs was assessed by the endothelial gap closure assay and found to be significant for both gel constructs assessed (Figure 4), indicating that MSC EVs can retain activity for sustained release applications.
Conclusions: MSC EVs can be incorporated into 3D-printed, photo-crosslinked GelMA constructs. Further, EV burst release can be significantly reduced by increasing the crosslinker (LAP) concentration during gelation can be used as a sustained wound healing treatment.
