Graphene oxide from silk cocoon: a novel magnetic fluorophore for multi-photon imaging.
In this work, we synthesized graphene oxide from silk cocoon embarking its new dimension as a magnetic fluorophore when compared with its present technical status, which at best is for extracting silk as a biomaterial for tissue engineering applications. We produced graphene oxide by pyrolysing the silk cocoon in an inert atmosphere. The collected raw carbon is oxidized by nitric acid that readily produces multilayer graphene oxide with nano carbon particulates. Structural properties of the graphene oxide were analyzed using scanning electron microscopy, transmission electron microscopy, Fourier transform infra-red spectroscopy, and Raman spectroscopy. The oxidized sample shows remarkable fluorescence, multi-photon imaging and magnetic properties. On increasing the excitation wavelength, the fluorescence emission intensity of the graphene oxide also increases and found maximum emission at 380 nm excitation wavelength. On studying the two photon absorption (TPA) property of aqueous graphene oxide using Z-scan technique, we found significant TPA activity at near infrared wavelength. In addition, the graphene oxide shows ferromagnetic behavior at room temperature. The observed fluorescence and magnetic property were attributed to the defects caused in the graphene oxide structure by introducing oxygen containing hydrophilic groups during the oxidation process. Previously silk cocoon has been used extensively in deriving silk-based tissue engineering materials and as gas filter. Here we show a novel application of silk cocoon by synthesizing graphene oxide based magnetic-fluorophore for bio-imaging applications.
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Manas
M
Roy
Department of Biological Sciences and Bioengineering, Bioelectricity, Green Energy, Physiology and Sensor Group, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Tejas Sanjeev
TS
Kusurkar
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.|Center for Laser Technology, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Sandeep Kumar
SK
Maurya
Department of Electrical Engineering, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Sunil Kumar
SK
Meena
MEMS and Photonics Division, Solid State Physics Laboratory, Defense Research Development Organization, Timarpur, Delhi, 110054, India.
Sushil Kumar
SK
Singh
Peptide and Proteomics Division, Defense Institute of Physiology and Allied Sciences, Defense Research Development Organization, Timarpur, Delhi, 110054, India.
Niroj
N
Sethy
Peptide and Proteomics Division, Defense Institute of Physiology and Allied Sciences, Defense Research Development Organization, Timarpur, Delhi, 110054, India.
Kalpana
K
Bhargava
Department of Chemistry, Division of Physical Chemistry, Electrochemical Materials Research Group, University of Delhi, Delhi, 110007, India.
Raj Kishore
RK
Sharma
Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.|Center for Laser Technology, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India.
Debabrata
D
Goswami
Department of Chemistry, Bengal Engineering and Science University, Shibpur, Botanical Garden, Howrah, 711103, West Bengal, India.
Sabyasachi
S
Sarkar
Department of Biological Sciences and Bioengineering, Bioelectricity, Green Energy, Physiology and Sensor Group, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India. mainakd@iitk.ac.in.|Design Program, Indian Institute of Technology Kanpur, Kanpur, 208016, Uttar Pradesh, India. mainakd@iitk.ac.in.
Mainak
M
Das
Bio-imaging; Fluorophore; Graphene oxide; Magnetism; Multi-photon imaging; Silk cocoon