We have designed and developed a sample cell to collect volatile organic compounds (VOCs) of exhaled breath in an aqueous medium. The developed sample cell is designed to avoid sample loss or contamination and to fulfill the necessary condition to perform surface-enhanced Raman spectroscopy (SERS) experiments through plasmonic self-assembly of metallic nanoparticles to identify the VOCs of lung cancer. The above-mentioned sample cell will be utilized to collect the exhaled breath from the healthy volunteers (research scholars, faculty members, and junior engineers from the Department of Atomic and Molecular Physics) and from the lung cancer patients visiting the Department of Medical Oncology and Department of Respiratory Medicine KMC, Manipal during the OPD visits. The breath sample will be collected after at least 3 to 4 hours of fasting, and the participants are instructed to avoid smoking and alcohol consumption to avoid contamination. While collecting the breath sample, general instructions will be given to blow the breath into the sample cell through the mouthpiece; if necessary, a short demo will be given by the instructor. Immediately after completing 8 to 10 exhalations from the participants, the sample cell will be closed, and the mouthpiece and tube connected to the sample cell will be disposed of.

The collected exhaled breath in the sample cell will be subjected to the in situ SERS measurements using the developed optical setup. It comprises a 785 nm diode laser, an upright microscope, a compact CCD-spectrometer, and the sample cell discussed earlier. The obtained SERS spectra will be compared to discriminate the human breath samples of lung cancer patients from those of healthy volunteers.