Bilayered BMP2 Eluting Coatings on Graphene Foam by Electrophoretic Deposition: Electroresponsive BMP2 Release and Enhancement of Osteogenic Differentiation

Abstract

Recent development of three-dimensional graphene foam (GF) with conductive and interconnected macroporous structure is attracting particular attention as platforms for tissue engineering. However, widespread application of GF as bone scaffolds is restricted due to its poor mechanical property and inert surface character. To overcome these drawbacks, in this study, a bilayered biopolymer coating was designed and successfully deposited covering the entire surface area of GF skeleton. A poly(lactic-co-glycolic acid) layer was first dip-coated to strengthen the GF substrate, followed by the electrophoretic codeposition of a hybrid layer, consisting of chitosan and BMP2, to functionalize GF with the ability to recruit and induce osteogenic differentiation of hMSC. Our data indicated that the mechanical property of GF was significantly increased without compromising the macroporous structure. Importantly, the immobilized BMP2 exhibited sustained and electroresponsive release profiles with rapid response to the electric field exerted on GF, which is beneficial to balancing BMP2 dose in a physiological environment. Moreover, the osteogenic differentiation of hMSC was significantly improved on the functionalized GF. Taking advantage of the unique macrostructure from GF as well as the superior mechanical properties and BMP2 release profile supported by the deposited coatings, it is therefore expected that the developed GF could be a promising alternative as innovative bone-forming favorable scaffolds.

Mechanical Properties of Graphene Foam and Graphene Foam—Tissue Composites

“…This table highlights the variation in mechanical properties due to testing mechanism, graphene synthesis methods, and the addition of natural and synthetic polymers. CVD GF has been shown to support the growth of ATDC5 chondroprogenitor cells, C2C12 mouse myoblast cells, [14] MC3T3-E1 osteoblasts [25] , hMSCs, [15]–[17][26] and neural stem cells. [18] The mechanical properties of CVD GF are dependent on both the template structure and the density of graphene deposited on the template.…”

“…[24] GF’s surface chemistry can be altered using various biopolymers to tune its strength and surface energy characteristics to meet the requirements of different cell lines. [17][25][26] The electrical properties of GF allow for electro-mechanical stimulation and it has been shown that the conductivity of GF remains stable with no production of harsh byproducts, unlike conductive polymers. [27] Finally, graphene materials demonstrate antibacterial and antifungal properties in wound infection, suggesting potential for anti-infective properties in tissue engineering applications.…”

“…[17][26][38] Additionally, we aimed to elucidate time dependent changes in the mechanical properties of GF scaffold as chondroprogenitor cells (ATDC5) are cultured over a period of 28 days.…”

BMP9 promotes osteogenic differentiation of SMSCs by activating the JNK/Smad2/3 signaling pathway

“…BMPs play a critical role in cell proliferation, differentiation, apoptosis, body development, and organogenesis, and 15 of these known proteins have been found in humans . BMP2, BMP4, and BMP7 exhibit excellent osteogenic capacity that has been widely used in the clinics . However, nonfusion spine formation induced by BMP2 and BMP7 could be occasionally reported in the clinics .…”

“…22 BMP2, BMP4, and BMP7 exhibit excellent osteogenic capacity that has been widely used in the clinics. [23][24][25] However, nonfusion spine formation induced by BMP2 and BMP7 could be occasionally reported in the clinics. 26 Since BMP9 was discovered, it has received wide attention due to its higher ability to stimulate bone formation than other members of the BMP family.…”