Carboxylation of multiwalled carbon nanotubes reduces their toxicity in primary human alveolar macrophages - Sweeney, S; Hu, S; Ruenraroengsak, P; Chen, S; Gow, A; Schwander, S; Zhang, JJ; Chung, KF; Ryan, MP; Porter, AE; Shaffer, MS; Tetley, TD (Environmental Science: Nano, 2016)