Polyethylene glycol modified-carbon nanotubes as materials for biomedical applications: in vitro and in vivo sub-acute toxicity evaluation by Mohd. Radzi, Muhammad Redza, Yong, Sin Yee, Mock, Phooi Yan, Johari, Nur Amanina, Wan Mohd. Zawawi, Wan Fatin Amira, Aminullah Lubis, Faridah, Muhamad Hendri, Nur Afrina, Raj, Santhana, Jemon, Khairunadwa