Charge effect of superparamagnetic iron oxide nanoparticles on their surface functionalization by photo-initiated chemical vapour deposition
Diverse applications of superparamagnetic iron oxide nanoparticles (SPIONs) in the chemical and biomedical industry depend on their surface properties. In this paper, we investigate the effect of initial surface charge (bare, positively and negatively charged SPIONs) on the resulting physicochemical properties of the particles following treatment through photo-initiated chemical vapour deposition (PICVD). Transmission electron microscopy shows a nanometric polymer coating on the SPIONs and contact angle measurements with water demonstrate that their surface became non-polar following functionalization using PICVD. FTIR and XPS data confirm the change in the chemical composition of the treated SPIONs. Indeed, XPS data reveal an initial charge-dependent increase in the surface oxygen content in the case of treated SPIONs. The O/C percentage ratios of the bare SPIONs increase from 1.7 to 1.9 after PICVD treatment, and decrease from 1.7 to 0.7 in the case of negatively charged SPIONs. The ratio remains unchanged for positively charged SPIONs (1.7). This indicates that bare and negatively charged SPIONs showed opposite preference for the oxygen or carbon attachment to their surface during their surface treatment. These results reveal that both the surface charge and stereochemical effects have determinant roles in the polymeric coating of SPIONs with PICVD. Our findings suggest that this technique is appropriate for the treatment of nanoparticles.
KeywordsSuperparamagnetic iron oxide nanoparticles PICVD Contact angle FTIR TEM XPS
We thank Professor Nick Virgilio from École Polytechnique de Montréal for access to the tensiometer. We also acknowledge the (CM)2 laboratory at École Polytechnique de Montréal for the TEM imaging of the samples. Finally, the authors would like to acknowledge the financial support of the National Science and Engineering Research Council of Canada (NSERC). The ARC (Research Contract AUWB-2010—10/15-UMONS-5), the FNRS, the Walloon Region, the COST TD1004 and TD1402, the UIAP VII program and the Center for Microscopy and Molecular Imaging (CMMI, supported by the European Regional Development Fund and the Walloon Region) are thanked for their support.
- Chen FF, Gerion D, Gray JW, Budinger TF (2009) Multimodal imaging probes for in vivo targeted and non-targeted imaging and therapeutics. US Patent WO2009045579 A2Google Scholar
- Eigler DM, Heinrich AJ, Loth S, Lutz CP (2014) Antiferromagnetic storage device. US Patent US8,724,376 B2Google Scholar
- Hanini A, Schmitt A, Kacem K, Chau F, Ammar S, Gavard J (2011) Evaluation of iron oxide nanoparticle biocompatibility. Int J Nanomed 6:787–794Google Scholar
- Misra D, Wörhoff K, Mascher P (2003) Dielectrics in emerging technologies. In: Proceedings of the international symposium, Electrochem Society, Washington, DCGoogle Scholar