In Vitro Photoacoustic Flow Cytometry: A Non-invasive Flow Photoacoustic Technique to Detect Nanoparticle-bearing Circulating Ovarian Cancer Cells

Photoacoustic flow cytometry, or PAFC, utilizes the ability of biological samples to absorb laser light of a specific wavelength and emit acoustic sound waves. Begin by taking a suspension of the desired nanoparticle-bearing ovarian cancer cells in one syringe and air in a second syringe. Load the two syringes onto two separate syringe pumps set to their respective flow rates. The pumps deliver their contents through flexible tubes that merge to administer small volumes of sample trapped between alternating air bubbles to a pre-assembled flow chamber.

As the sample passes through the flow chamber, irradiate the cells using a short-pulsed laser of an appropriate wavelength. Localized absorption of laser energy by the nanoparticles within the cancer cells generates heat, causing thermoelastic expansion that produces acoustic sound waves. A pre-assembled transducer detects the acoustic signals and transmits them to a receiver. The receiver amplifies the signals and relays them to an oscilloscope for data acquisition. The oscilloscope processes the data and transfers them to a computer that displays information relating to the detected cancer cells.