Search

We recently reported a standardized xeno- and serum-free culture platform to isolate and expand umbilical cord-derived mesenchymal stem/stromal cells (UC-MSCs). Comparing populations from the same passage, cells that were cryopreserved and culture-rescued exhibited characteristics similar to those of their fresh counterparts, continuously cultured cells without interim cryopreservation. The culture rescue after thawing allowed for the cells to be fully recovered. However, since it would be more cost-effective and timesaving if cryopreserved cells can be used as an off-the-shelf product, we set out to compare the bioactivity of freshly thawed UC-MSCs versus culture-rescued UC-MSCs of the same batch that were recultured for an additional passage under our xeno- and serum-free protocol. UC-MSCs showed high viability in both the freshly thawed and the re-cultured group. Both populations displayed a similar proliferation capacity which is indicated by a comparable population doubling time and colony-forming ability. Both freshly thawed and culture-rescued UC-MSCs expressed the characteristic immunophenotype and were capable of differentiating into osteocytes, chondrocytes, and adipocytes. On the other hand, culture-rescued cells appeared to be more potent in immunosuppression than freshly thawed cells. In conclusion, freshly thawed and culture-rescued cell products share comparable bioactivity in cell growth and proliferation, immunophenotype, and differentiation potential. However, the culture-rescued cells that were allowed to grow for an additional passage appear to display a more favorable immunomodulatory potential when compared to their freshly thawed parent cells.

Background: Bronchopulmonary dysplasia (BPD) is a severe condition in premature infants that compromises lung function and necessitates oxygen support. Despite major improvements in perinatal care minimizing the devastating effects, BPD remains the most frequent complication of extreme preterm birth. Our study reports the safety of the allogeneic administration of umbilical cord-derived mesenchymal stem/stromal cells (allo-UC-MSCs) and the preliminary improvements in four infants with established BPD.Methods: UC tissue was collected from a healthy donor, followed by propagation at the Stem Cell Core Facility at Vinmec Research Institute of Stem Cell and Gene Technology. UC-MSC culture was conducted under xeno- and serum-free conditions. Four patients with established BPD were enrolled in this study between May 25, 2018, and December 31, 2018. All four patients received two intravenous doses of allo-UC-MSCs (1 million cells/kg patient body weight (PBW) per dose) with an intervening interval of 7 days. Safety and patient conditions were evaluated during hospitalization and at 7 days and 1, 6 and 12 months postdischarge.Results: No intervention-associated severe adverse events or prespecified adverse events were observed in the four patients throughout the study period. At the time of this report, all patients had recovered from BPD and were weaned off of oxygen support. Chest X-rays and CT scans confirmed the potential reductions in fibrosis.Conclusions: Allo-UC-MSC administration is safe and might improve respiratory function and decrease lung fibrosis in preterm infants with established BPD.Trial registration: This preliminary study was approved by the Vinmec International Hospital Ethics Board (approval number: 88/2019/QĐ-VMEC; retrospectively registered March 12, 2019).

Background: Bronchopulmonary dysplasia (BPD) is a severe condition in premature infants that compromises theirlung function and necessitatesoxygen support. Despite major improvements in perinatal care minimizing the devastating effects, BPD remains the most frequent complication of extreme preterm birth. Our study reports the safety ofthe allogeneic administration of umbilical cord-derived mesenchymal stem/stromal cells (allo-UC-MSCs) and the preliminary efficacy of the treatment in four infants with established BPD.Methods: UC tissue was collected from a healthy donor, followed by propagation at the Stem Cell Core Facility at Vinmec Research Institute of Stem Cell and Gene Technology. UC-MSC culture was conducted under xeno-free and serum-free conditions. Four patients with established BPD were enrolled in this study between May 25, 2018, and December 31, 2018. All four patients received two intravenous doses of allo-UC-MSCs (1 million cells/kg patient body weight (PBW) per dose) with an intervening interval of 7 days. Safety and efficacy were evaluated during hospitalization and at 7 days and 1, 6 and 12 postdischargemonths.Results: No transplantation-associated severe adverse events or prespecified adverse events were observed in the four patients throughout the study period. At the time of this report, all patients had recovered from BPD and been weaned off of oxygen support. Chest X-rays and CT scans confirmed the dramatic reduction infibrosis.Conclusions: Allo-UC-MSC transplantation is safe and might improve respiratory function anddecrease lung fibrosis in preterm infants with established BPD.Trial registration: This preliminary study was approved by Vinmec International Hospital Ethics Board, approval number: 88/2019/QĐ-VMEC, registered 12 March 2019 - retrospectively registered.

In this work, we systematically investigate the electronic and optical properties of surface-functionalized GeC monolayer with F and Cl using density functional theory. Our calculations indicate that the surface functionalization of the GeC with F and C atoms leads to the disruption of the planar structure of the GeC monolayer and the surface-functionalized GeC monolayer has a low-bucking structure. At equilibrium, all four configurations of surface-functionalized GeC monolayer with F and Cl, i.e., F–GeC–F, F–GeC–Cl, Cl–GeC–F, and Cl–GeC–Cl, are direct semiconductors. Their band gaps vary from 2.839 eV to 3.175 eV which are calculated using Heyd–Scuseria–Ernzerhof (HSE) hybrid functional. Compared to the other configurations, the formation energy of F–GeC–F is the smallest, − 9 . 097 eV , which implies that this configuration is the most likely to occur. We also used the Mulliken population analysis to estimate the internal charge distribution and transferred charge in the systems. The functionalization of the surface leads to the shifting the first optical gap of the material. The fully chlorination of GeC causes its absorption coefficient to increase significantly, up to 14 . 912 × 1 0 4 cm−1 at the incident light energy of 13.173 eV. Besides, surface-functionalized GeC monolayer with F and Cl strongly absorbs light in the near ultraviolet region. Our calculation results provide detailed information on how to change the electronic and optical properties of monolayer GeC by surface functionalization, which has promising applications in opto-electronic devices.

In this work, we study the electronic, optical, and photocatalytic properties of fully hydrogenated GeC monolayer under strain engineering and external electric field using first-principles investigations. Our calculations demonstrate that at the equilibrium state, fully hydrogenated GeC monolayer is a indirect semiconductor with band gap of 3.493 eV and it possesses photocatalytic characteristics for water splitting and in particular, photocatalytic activities can be enhanced by a negative electric field under ultraviolet light.We can control the band gap of fully hydrogenated GeC monolayer by biaxial strain or external electric field and semiconductor-metal phase transition happens at certain elongation of biaxial strain. Compared to pure monolayer GeC, the fully hydrogenation causes optical absorption peaks of GeC shifting to a higher energyregion. While the optical spectra of the fully hydrogenated GeC monolayer are strongly dependent on the strain, the effect of the electric field on them is negligible. Our findings can provide useful information for the applicability of fully hydrogenated GeC monolayer in nanoelectronic devices and photocatalytic water splitting. Refereed/Peer-reviewed