Ultrasound-assisted laser therapy for selective removal of melanoma cells.

The current study explores the potential of ultrasound-assisted laser therapy (USaLT) to selectively destroy melanoma cells. The technology was tested on an ex vivo melanoma model, which was established by growing melanoma cells in chicken breast tissue. Ultrasound-only and laser-only treatments were used as control groups. USaLT was able to effectively destroy melanoma cells and selectively remove 66.41% of melanoma cells in the ex vivo tumor model when an ultrasound peak negative pressure of 2 MPa was concurrently applied with a laser fluence of 28 mJ/cm² at 532 nm optical wavelength for 5 min. The therapeutic efficiency was further improved with the use of a higher laser fluence, and the treatment depth was improved to 3.5 mm with the use of 1,064 nm laser light at a fluence of 150 mJ/cm². None of the laser-only and ultrasound-only treatments were able to remove any melanoma cells. The treatment outcome was validated with histological analyses and photoacoustic imaging. This study opens the possibility of USaLT for melanoma that is currently treated by laser therapy, but at a much lower laser fluence level, hence improving the safety potential of laser therapy.