Injectable and Crosslinkable PLGA‐Based Microribbons as 3D Macroporous Stem Cell Niche

• Published in: Small (Weinheim an der Bergstrasse, Germany) Vol. 16; no. 22; pp. e1905820 - n/a
• Main Authors: Barati, Danial, Watkins, Kira, Wang, Zhibin, Yang, Fan
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 01.06.2020
• Subjects: Alkaline phosphatase; Aqueous solutions; Biomedical materials; Crosslinking; Encapsulation; Fibrinogen; Hydrogels; Injectability; microribbons; Modulus of elasticity; Nanotechnology; poly(lactide‐co‐glycolide) (PLGA); Regeneration; Robustness; Scaffolds; stem cell niche; Stem cells; Thrombin; Tissue engineering; tissue regeneration; microribbons; stem cells; tissue regeneration; stem cell niche; scaffolds; poly(lactide-co-glycolide) (PLGA)
• ISSN: 1613-6810; 1613-6829; 1613-6829
• DOI: 10.1002/smll.201905820

Poly(lactide‐co‐glycolide) (PLGA) has been widely used as a tissue engineering scaffold. However, conventional PLGA scaffolds are not injectable, and do not support direct cell encapsulation, leading to poor cell distribution in 3D. Here, a method for fabricating injectable and intercrosslinkable PLGA microribbon‐based macroporous scaffolds as 3D stem cell niche is reported. PLGA is first fabricated into microribbon‐shape building blocks with tunable width using microcontact printing, then coated with fibrinogen to enhance solubility and injectability using aqueous solution. Upon mixing with thrombin, firbornogen‐coated PLGA microribbons can intercrosslink into 3D scaffolds. When subject to cyclic compression, PLGA microribbon scaffolds exhibit great shock‐absorbing capacity and return to their original shape, while conventional PLGA scaffolds exhibit permanent deformation after one cycle. Using human mesenchymal stem cells (hMSCs) as a model cell type, it is demonstrated that PLGA μRB scaffolds support homogeneous cell encapsulation, and robust cell spreading and proliferation in 3D. After 28 days of culture in osteogenic medium, hMSC‐seeded PLGA μRB scaffolds exhibit an increase in compressive modulus and robust bone formation as shown by staining of alkaline phosphatase, mineralization, and collagen. Together, the results validate PLGA μRBs as a promising injectable, macroporous, non‐hydrogel‐based scaffold for cell delivery and tissue regeneration applications. Poly(lactide‐co‐glycolide) (PLGA) has been widely used for fabricating 3D scaffolds. Previous methods for fabricating PLGA scaffolds do not support direct encapsulation and are not injectable. Here, a method to first fabricate PLGA into microribbon shape building blocks, which are injectable and can intercrosslink into 3D macroporous scaffolds while supporting homogeneous cell encapsulation and minimally invasive delivery, is reported.