Jinkyu Lee1,2, Sangmin Lee1,3, Sung Min Kim4,5,6, Heungsoo Shin7,8,9. 1. Department of Bioengineering, Hanyang University, Seoul, 04763, Republic of Korea. 2. BK21 FOUR, Human-Tech Convergence Program, Hanyang University, Seoul, 04763, Republic of Korea. 3. BK21 FOUR, Education and Research Group for Biopharmaceutical Innovation Leader, Hanyang University, Seoul, 04763, Republic of Korea. 4. BK21 FOUR, Human-Tech Convergence Program, Hanyang University, Seoul, 04763, Republic of Korea. minarthur@hanyang.ac.kr. 5. Department of Physical Education and Active Aging Industry, Hanyang University, Seoul, 04763, Republic of Korea. minarthur@hanyang.ac.kr. 6. Center for Artificial Intelligence Muscle, Hanyang University, Seoul, 04763, Republic of Korea. minarthur@hanyang.ac.kr. 7. Department of Bioengineering, Hanyang University, Seoul, 04763, Republic of Korea. hshin@hanyang.ac.kr. 8. BK21 FOUR, Education and Research Group for Biopharmaceutical Innovation Leader, Hanyang University, Seoul, 04763, Republic of Korea. hshin@hanyang.ac.kr. 9. Institute of Nano Science and Technology, Hanyang University, Seoul, 04763, Republic of Korea. hshin@hanyang.ac.kr.
Abstract
BACKGROUND: Fabrication of three-dimensional stem cell spheroids have been studied to improve stem cell function, but the hypoxic core and limited penetration of nutrients and signaling cues to the interior of the spheroid were challenges. The incorporation of polymers such as silica and gelatin in spheroids resulted in relatively relaxed assembly of composite spheroids, and enhancing transport of nutrient and biological gas. However, because of the low surface area between cells and since the polymers were heterogeneously distributed throughout the spheroid, these polymers cannot increase the cell to extracellular matrix interactions needed to support differentiation. METHODS: We developed the stem cell spheroids that incorporate poly(ι-lactic acid) single-segmented fibers synthesized by electrospinning and physical and chemical fragmentation. The proper mixing ratio was 2000 cells/μg fibers (average length of the fibers was 50 μm - 100 μm). The SFs were coated with polydopamine to increase cell binding affinity and to synthesize various-sized spheroids. The function of spheroids was investigated by in vitro analysis depending on their sizes. For statistical analysis, Graphpad Prism 5 software (San Diego, CA, USA) was used to perform one-way analysis of variance ANOVA with Tukey's honest significant difference test and a Student's t-test (for two variables) (P < 0.05). RESULTS: Spheroids of different sizes were created by modulating the amount of cells and fibers (0.063 mm2-0.322 mm2). The fibers in the spheroid were homogenously distributed and increased cell viability, while cell-only spheroids showed a loss of DNA contents, internal degradation, and many apoptotic signals. Furthermore, we investigated stemness and various functions of various-sized fiber-incorporated spheroids. In conclusion, the spheroid with the largest size showed the greatest release of angiogenic factors (released VEGF: 0.111 ± 0.004 pg/ng DNA), while the smallest size showed greater effects of osteogenic differentiation (mineralized calcium: 18.099 ± 0.271 ng/ng DNA). CONCLUSION: The spheroids incorporating polydopamine coated single-segmented fibers showed enhanced viability regardless of sizes and increased their functionality by regulating the size of spheroids which may be used for various tissue reconstruction and therapeutic applications.
BACKGROUND: Fabrication of three-dimensional stem cell spheroids have been studied to improve stem cell function, but the hypoxiccore and limited penetration of nutrients and signaling cues to the interior of the spheroid were challenges. The incorporation of polymers such as silica and gelatin in spheroids resulted in relatively relaxed assembly of composite spheroids, and enhancing transport of nutrient and biological gas. However, because of the low surface area between cells and since the polymers were heterogeneously distributed throughout the spheroid, these polymerscannot increase the cell to extracellular matrix interactions needed to support differentiation. METHODS: We developed the stem cell spheroids that incorporate poly(ι-lactic acid) single-segmented fibers synthesized by electrospinning and physical and chemical fragmentation. The proper mixing ratio was 2000 cells/μg fibers (average length of the fibers was 50 μm - 100 μm). The SFs were coated with polydopamine to increase cell binding affinity and to synthesize various-sized spheroids. The function of spheroids was investigated by in vitro analysis depending on their sizes. For statistical analysis, Graphpad Prism 5 software (San Diego, CA, USA) was used to perform one-way analysis of variance ANOVA with Tukey's honest significant difference test and a Student's t-test (for two variables) (P < 0.05). RESULTS: Spheroids of different sizes were created by modulating the amount of cells and fibers (0.063 mm2-0.322 mm2). The fibers in the spheroid were homogenously distributed and increased cell viability, while cell-only spheroids showed a loss of DNA contents, internal degradation, and many apoptotic signals. Furthermore, we investigated stemness and various functions of various-sized fiber-incorporated spheroids. In conclusion, the spheroid with the largest size showed the greatest release of angiogenic factors (released VEGF: 0.111 ± 0.004 pg/ng DNA), while the smallest size showed greater effects of osteogenic differentiation (mineralized calcium: 18.099 ± 0.271 ng/ng DNA). CONCLUSION: The spheroids incorporating polydopaminecoated single-segmented fibers showed enhanced viability regardless of sizes and increased their functionality by regulating the size of spheroids which may be used for various tissue reconstruction and therapeutic applications.
Entities:
Keywords:
Angiogenic factor; Differentiation; Single segmented fibers; Spheroid; Stem cell
Authors: David Choy Buentello; Lena Sophie Koch; Grissel Trujillo-de Santiago; Mario Moisés Alvarez; Kerensa Broersen Journal: PLoS One Date: 2022-05-10 Impact factor: 3.752