Accurate determination of gold nanorods concentrations from optoacoustic signals detected at 870 nm and 905 nm by using high-power diode lasers with fast switching electronics

Optoacoustic imaging (OAI) is an emerging biomedical technique that allows visualization of in-depth tissues by using ultrasonic signals generated by short laser pulses. In this work, the authors combine the optical power of several pulsed high-power diode lasers (HPDLs) at 870 nm and 905 nm to a 7-to-1 675-mum fiber bundle to generate optoacoustic (OA) signals from different mixtures of two gold nanorods solutions with absorbance peak at ~860 nm and ~900 nm, respectively. The pulses produced to generate OA signals are alternated between the two wavelengths by a microcontroller circuit with fast switching (0.5 ms). From the amplitude of the OA signals, the concentrations of the nanoparticles solutions are easily estimated with high accuracy using a fluence model. The results achieved with the proposed system show very good agreement between the concentrations of gold nanorods estimated from measurements and the expected values.

Accurate determination of gold nanorods concentrations from optoacoustic signals detected at 870 nm and 905 nm by using high-power diode lasers with fast switching electronics Articles