Interactions between carbon nanotubes and bioactives: a drug delivery perspective

• CNTs are considered as superior adsorbent for adsorption of guest molecules.
• Functionalization is a well-known approach for alteration of the surface.
• Purification is a prime factor in CNTs.
• Conjugation of PEG to nanobiomaterials is known as PEGylation.
• Stimuli-responsive engineered CNTs may offer interesting opportunities in targeting.

Applications of carbon nanotubes (CNTs) in the biomedical arena have gained increased attention over the past decade. Surface engineering of CNTs by covalent and noncovalent modifications enables site-specific drug delivery and targeting. CNTs are available as single-, double-, triple-, and multiwalled carbon nanotubes (SWCNTs, DWCNTs, TWCNTs, and MWCNTs, respectively) and have unique physicochemical properties, including a high surface area, high loading efficiency, good biocompatibility, low toxicity, ultra lightweight, rich surface chemistry, non-immunogenicity, and photoluminescence. In this review, we highlight current understanding of the different types of physical and chemical interaction that occur between therapeutics and CNTs, and the potential application of the latter in drug delivery and imaging. Such understanding will aid exploration of the utility of multifunctional CNTs as pharmaceutical nanocarriers, and potential safety and toxicity issues.