After fabricating the gold carbon dots composite nanoparticles, place a sterile sapphire chip into the 24-well plates and seed cells with one milliliter of the medium into a single well. Incubate the plates in a humid environment to attain 70 to 80%confluence. Add the gold carbon dots composite nanoparticles to the single well and incubate for four to six hours.
At the end of the incubation, remove the medium from the sapphire chips. Gently rinse the chips with PBS and dip the sapphire chips in PBS for SERS detection. To perform the SERS experiment, switch on the computer, Raman spectrometer, and 785 nanometer laser.
Next, start the accompanying software and perform calibration using silicon wafers. Click new measurement followed by spectral acquisition and adjust the spectrum range. Then go to the acquisition tab, adjust the exposure time and laser power, and click OK to initiate a new spectral acquisition.
Use a 20X objective lens for a clear cellular image. Then switch to a 50X lens. After selecting a point on the cells for measurement, click run to initiate the process and then save the spectra.
To obtain SERS imaging of A549 cells, click new streamline image acquisition, select the range to be photographed and click OK.Set the edge streamline to 785 nanometers center to 1, 200 centimeter inverse, exposure duration to five seconds, and laser power to 50%The parameter can be modified as required. Click on new of live imaging, choose signal to baseline and set the first limit to 725 and the second limit to 1, 700. Then go to area set up, set the proper steps and click on OK.Finally, click run to start performing SERS imaging.
SERS Spectra revealed that even when the concentration of methylene blue is as low as 10 to the minus nine molar, gold carbon dots composite nanoparticles exhibit excellent SERS performance compared to gold nanoparticles. SERS spectra acquired on 20 points exhibited high similarity. One month after the placement of gold carbon dots composite nanoparticles at four degrees Celsius, the average SERS activity at 950, 1, 185 and 1, 620 centimeters inverse showed a degree of decay of about 5.43%11.44%and 13.94%respectively.
Gold carbon dots composite nanoparticles barely showed cytotoxicity to A549 cells. The mean spectrum of A549 cells is presented. Gold carbon dots composite nanoparticle aggregates exhibit obvious SERS signals without noise background in the SERS mapping of A549 cells.
Spectra from different cell points demonstrated the heterogeneity of components in various cytoplasmic regions.
