abstract
Nano-graphene oxide (nano-GO) is a new class of carbon based materials being proposed for biomedical applications due to its small size, intrinsic optical properties, large specific surface area, and easy to functionalize. To fully exploit nano-GO properties, a reproducible method for its production is of utmost importance. Herein we report, the study of the sequential fracture of GO sheets onto nano-GO with controllable lateral width, by a simple, and reproducible method based on a mechanism that we describe as a confined hot spot atomic fragmentation/reduction of GO promoted by ultrasonication. The chemical and structural changes on GO structure during the breakage were monitored by XPS, FTIR, Raman and HRTEM. We found that GO sheets starts breaking from the defects region and in a second phase through the disruption of carbon bonds while still maintaining crystalline carbon domains. The breaking of GO is accompanied by its own reduction, essentially by the elimination of carboxylic and carbonyl functional groups. Photoluminescence and photothermal studies using this nano-GO are also presented highlighting the potential of this nanomaterial as a unique imaging/therapy platform.
keywords
PHOTOTHERMAL THERAPY; GRAPHITE OXIDE; QUANTUM DOTS; BIOMEDICAL APPLICATIONS; CONFORMATIONAL-CHANGES; CARBON NANOCRYSTALS; STRUCTURAL MODEL; NANO-GRAPHENE; SHEETS; EXFOLIATION
subject category
Science & Technology - Other Topics
authors
Goncalves, G; Vila, M; Bdikin, I; de Andres, A; Emami, N; Ferreira, RAS; Carlos, LD; Gracio, J; Marques, PAAP
our authors
Luís Carlos
Full professor
Maria Rute de Amorim e Sá Ferreira André
Full professoracknowledgements
Gil Goncalves thanks the Fundacao para a Ciencia e Tecnologia (FCT) for the PostDoc grant (SFRH/BDP/84419/2012). A de Andres thanks MINECO (MAT2012-37276-C03-01) project. M Vila thanks the FCT for the 2013 investigator grant. We would like to thank Fundacao para a Ciencia e a Tecnologia (FCT, Portugal), the European Union, QREN, FEDER, COMPETE, for funding the TEMA Research Unit (PEst-C/QUI/UI0062/2013). The authors acknowledge the SUDOE and ERDF within the Territorial Cooperation Programme IVB funding through the project CarbonInspired 2.0 (Grant Agreement SOE4/P1/E793).