Synthesis and Characterization of Silver-Coated Polymeric Scaffolds for Bone Tissue Engineering: Antibacterial and In Vitro Evaluation of Cytotoxicity and Biocompatibility

Abstract

In bone tissue engineering, multifunctional composite materials are very challenging. Bone tissue engineering is an innovative technique to develop biocompatible scaffolds with suitable orthopedic applications with enhanced antibacterial and mechanical properties. This research introduces a polymeric nanocomposite scaffold based on arabinoxylan-co-acrylic acid, nano-hydroxyapatite (nHAp), nano-aluminum oxide (nAl₂O₃), and graphene oxide (GO) by free-radical polymerization for the development of porous scaffolds using the freeze-drying technique. These polymeric nanocomposite scaffolds were coated with silver (Ag) nanoparticles to improve antibacterial activities. Together, nHAp, nAl₂O₃, and GO enhance the multifunctional properties of materials, which regulate their physicochemical and biomechanical properties. Results revealed that the Ag-coated polymeric nanocomposite scaffolds had excellent antibacterial properties and better microstructural properties. Regulated morphological properties and maximal antibacterial inhibition zones were found in the porous scaffolds with the increasing amount of GO. Moreover, the nanosystem and the polymeric matrix have improved the compressive strength (18.89 MPa) and Young's modulus (198.61 MPa) of scaffolds upon increasing the amount of GO. The biological activities of the scaffolds were investigated against the mouse preosteoblast cell lines (MC3T3-E1) and increasing the quantities of GO helps cell adherence and proliferation. Therefore, our findings showed that these silver-coated polymeric nanocomposite scaffolds have the potential for engineering bone tissue.

Figure 1

Silver coating over the polymeric nanocomposite scaffolds to enhance their antibacterial activates.

Figure 2

Morphology of the synthesized particle sizes (A–C) of the polymeric nanocomposite through free radical polymerization via SEM. The polymeric nanocomposite material (AA-Ag-2) was selected for chemical composition analysis using SEM at 300 nm (D) and its EDX spectral profile (E) with percentage of elements (F).

Figure 3

FTIR spectrum profile of all samples of scaffolds to determine different functional groups.

Figure 4

SEM images of the rough and porous scaffolds present the morphology of the polymeric nanocomposite scaffolds at 200 μm resolution.

Figure 5

Mechanical and porous behavior of polymeric nanocomposite scaffolds has presented a (A) stress–strain curve, (B) shows the relationship of porosity (%) and Young’s modulus, (C) presents the relationship of ultimate compression and Young’s modulus.

Figure 6

Swelling analysis of scaffolds (A) in different media (PBS solution and H₂O) with pH 7.4 at 37 °C. Degradation phenomena (B) in PBS solution under in vitro (pH 7.4 at 37 °C) conditions of all samples of scaffolds.

Figure 7

Antibacterial activity of polymeric nanocomposite scaffolds against Gram +ive and Gram −ive bacterial strains and zones of inhibition were determined in mm.

Figure 8

The cell morphology of polymeric nanocomposite scaffolds against mouse preosteoblast (MC3T3-E1) cell lines after 48 and 72 h. The yellow arrows represent the thread-like morphology, and red arrows represent cylindrical and mature morphology.

Figure 9

Cell viability (A,C) and optical density (B,D) of all polymeric nanocomposite scaffolds against the MC3T3-E1 cell line at various concentrations (0.250, 0.500, 1.000, and 2.000 mg/mL) after different intervals (48 and 72 h) along with positive controls.