To further understand the reason for this, ZnO films were co-incubated with macrophages exposed to bacterial irritation, and the results showed that the release of pro-inflammatory cytokines, i.e. TNF-α, IL-6, monocyte chemoattractant protein-1 (MCP-1), was increased in the nano-ZnO group, and thus the overall effect of nano-ZnO films promoted the local inflammatory response, resulting in the recruitment of more immune cells to fight bacterial infections. The gene discussed is CCL2; the disease is bacterial infectious disease.