Micro-Raman Study of The Role of Sterilization on Carbon Nanotubes for Biomedical Applications

Abstract

Aim: We investigate the effect of four different types of sterilization procedures on the structural properties and morphological features of single-wall carbon nanotube samples approachable by micro-Raman spectroscopy. Sterilization procedures (treatment in humid heat autoclave or ethylene oxide and irradiation with γ-rays or UV light) are necessary in view of the use of carbon nanotube sterile samples in in vivo toxicity tests on laboratory rats. Micro-Raman spectroscopy allows us to estimate several details about the morphology of the single-wall carbon nanotube mixture (mainly the presence of disorder and diameter distribution) before and after the sterilization treatment. Results: The best of these treatments, in other words, the one that least affected the morphology and structural properties of carbon nanotubes, was found to be UV irradiation and has thus been selected for future in vivo tests on rats.

Keywords::

• biological effects
• carbon nanotubes
• nanomaterials
• Raman spectroscopy
• sterilization procedures
• toxicity

Financial & competing interests disclosure

This work was supported by the Italian Grant-Fondazione Cariplo (2006–0686) entitled “Diluted magnetic oxides thin films: towards transparent spintronics” and by the Italian Health Ministry Strategic Research Program PMS/40/06, ISPESL RFPS-2006–4–335269 “Innovative methodologies for risk assessment in occupational exposure to nanomaterials”. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Additional information

Funding

This work was supported by the Italian Grant-Fondazione Cariplo (2006–0686) entitled “Diluted magnetic oxides thin films: towards transparent spintronics” and by the Italian Health Ministry Strategic Research Program PMS/40/06, ISPESL RFPS-2006–4–335269 “Innovative methodologies for risk assessment in occupational exposure to nanomaterials”. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.