ABSTRACT
Traditional methods of detecting cancer cells, such as fluorescence, have their limits and can hardly be used for identification during tumor resection. Here we report an alternative tumor detection technology using ZnO nanorods bonded to antibodies as cancer cell probes. Our experiment shows that antibodies toward epidermal growth factor receptor (EGFR) can be connected to ZnO nanorods and to EGFR receptors of SCC (squamous cell carcinoma). The cancer cell can be recognized by the naked eye or an optical microscope with the help of purple light emission from ZnO/EGFR antibody probes. On the other hand, for cells with less EGFR expression, in our case Hs68, no purple light was observed as the probes were washed off. From the photoluminescent spectra, the peak intensity ratio between the purple light (from ZnO at the wavelength 377 nm) and the green band (from the autofluorescence of cells) is much higher with the presence in SCC, as compared with Hs68. The ZnO/EGFR antibody probes have the potential to be applied to surgery for real-time tumor cell identification. The cancer cells will be excised with the help of purple light emission.
Subject(s)
Carcinoma, Squamous Cell/diagnosis , Nanoconjugates/chemistry , Zinc Oxide/chemistry , Aluminum Oxide , Antibodies/chemistry , Antibodies/metabolism , Carcinoma, Squamous Cell/metabolism , Carcinoma, Squamous Cell/pathology , Case-Control Studies , Cell Line, Tumor , ErbB Receptors/metabolism , Humans , Luminescent Measurements/methods , Nanotubes/chemistry , Spectrometry, Fluorescence , Zinc Oxide/metabolismABSTRACT
Low-temperature electroluminescence from ZnO nanowire light-emitting arrays is reported. By inserting a thin MgO current blocking layer in between ZnO nanowire and p-GaN, high-purity UV light emission at wavelength 398 nm was obtained. As the temperature is decreased, contrary to the typical GaN-based light emitting diodes, our device shows a decrease of optical output intensity. The results are associated with various carrier tunneling processes and frozen MgO defects.
ABSTRACT
In this work, GZO/ZnO/GaN diodes with the light emitting ZnO layer sandwiched between two SiO(2) thin films was fabricated and characterized. We observed a strong excitonic emission at the wavelength 377nm with the Mg(2+) deep level transition and oxygen vacancy induced recombination significantly suppressed. In comparison, light emission from the GZO/GaN device (without SiO(2) barriers) is mainly dominant by defect radiation. Furthermore, the device with confinement layers demonstrated a much higher UV intensity than the blue-green emission of the GZO/GaN p-n device.