Self-assembled biomimetic Nano-Matrix for stem cell anchorage

Abstract

Mesenchymal stem cells (MSCs) have been widely applied in biomedicine due to their ability to differentiate into many different cell types and their ability to synthesize a broad spectrum of growth factors and cytokines that directly and indirectly influence other cells in their vicinity. To guide MSC infiltration to a bone fracture site, we developed a novel self-assembled Nano-Matrix which can be used as an injectable scaffold to repair bone fractures. The Nano-Matrix is formed by Janus base nanotubes (JBNTs) and fibronectin (FN). JBNTs are nucleobase-derived nanotubes mimicking collagen fibers, and FN is one of the cell adhesive glycoproteins which is responsible for cell-extracellular matrix interactions and guides stem cell migration and differentiation to desired cells types. Here, we demonstrated the successful fabrication and characterization of the JBNT/FN Nano-Matrix as well as its excellent bioactivity that encouraged human MSC migration and adhesion. This work lays a solid foundation for using the Nano-Matrix as an injectable approach to improve MSC retention and function during bone fracture healing.

Keywords: Janus-based nanotubes; Nano-Matrix; anchorage; fibronectin; mesenchymal stem cells.

FIGURE 1

Schematic illustration of the hierarchical self-assembly of Janus base nanotubes (JBNTs) with a lysine side chain

FIGURE 2

Demonstration for the self-assembled process of the Nano-matrix. (a) Fibronectin (FN) solution. (b) Janus base nanotubes (JBNTs) mixed with FN

FIGURE 3

Bright-field photographs of (a) fibronectin (FN), (b) Janus base nanotubes (JBNTs) and (c) Nano-Matrix formed by JBNTs and FN. Each area has a diameter of 2 cm

FIGURE 4

Absorption spectra of fibronectin (FN), Janus base nanotubes (JBNTs), and JBNT/FN Nano-Matrix

FIGURE 5

TEM images of (a) Janus base nanotubes (JBNTs), (b) JBNT/fibronectin (FN) Nano-Matrix, and (c) released JBNT/FN Nano-Matrix

FIGURE 6

Statistical analysis of cellular adhesion. Cell adhesion density was recorded in this experiment. *p < .01 compared to negative controls. **p < .05 compared to Janus base nanotube (JBNT) alone. N = 3

FIGURE 7

Statistical analysis of cell migration. *p < .01 compared to negative controls. **p < .05 compared to Janus base nanotube (JBNT) or fibronectin (FN) alone. N = 3

FIGURE 8

Fluorescence images of the (a) hMSCs and (b) hMSC incubated with the Janus base nanotube (JBNT)/fibronectin (FN) Nano-Matrix. Scale bar: 100 μm

FIGURE 9

Statistical analysis of cell morphology. (a) Cell circularity. (b) Cell roundness. *p < .05 compared to negative controls (NCs). **p < .05 compared to Janus base nanotube (JBNT) alone. #p < .05 compared to JBNT alone. N = 3