Towards biochemical sensing with gold nanoparticles through suppression of nonlinear photoacoustic signal generation

摘要

We propose a new method for biochemical sensing using photoacoustic (PA) excitation of gold nanoparticles (GNPs) toachieve real-time detection of transient biomarkers. Our approach is based on the effect of a particle coating on nonlinearPA signal generation combined with our recently-developed serial PA tomographic imaging method. We have shown theability to image the three-dimensional spatial distribution of GNPs that produce nonlinear PA signal with respect tofluence. If the occurrence of this nonlinearity is made dependent on the presence of transient biochemical markers, forexample through the degradation of a nonlinearity-quenching particle coating, our serial PA tomographic imagingmethod can be extended for real-time three-dimensional in situ imaging of these biomarkers. Our early-stage proof-ofconceptexperimental results presented here show that coating GNPs that exhibit nonlinear PA signal generationbehavior is an effective method to remove the nonlinear effect. The coefficient of determination (R2) of a linear fit to thePA signal as a function of fluence can be effectively used to differentiate the coated GNPs and the GNPs withoutcoating. This differentiation can also be achieved using the second order coefficient to a quadratic fit to the PA signal vs.Fluence data.