Plasmonic Nanoprobe of (Gold Triangular Nanoprism Core)/(Polyaniline Shell) for Real-Time Three-Dimensional pH...

Three-dimensional (3D) molecular imaging enables the study of biological processes in both living and nonviable systems at the molecular level and has a high potential on early diagnosis. In conjunction with specific molecular probes, optical coherent tomography (OCT) is a promising imaging modality to provide 3D molecular features at the tissue level. In this study, we introduced (gold triangular nanoprism core)/(polyaniline shell) nanoparticles (GTNPs@PANI) as an OCT contrast agent and pH-responsive nanoprobe for 3D imaging of pH distribution. These core/shell nanoparticles possessed significantly different extinction and scattering properties in acidic and basic microenvironments. The switch of the optical features of the nanoparticles upon pH change was reversible, and the response time was less than 1.0 s. The nanoprobe successfully indicated the acid regions of a mimic tumor from the basic region in a gelatin-based phantom under OCT imaging. As a demonstration of practical applications, real-time 3D OCT imaging of pH and lactic acid in the anterior chamber of a fish eye was realized by GTNPs@PANI nanoparticles. Using GTNPs@PANI nanoparticles as the contrast probes for OCT imaging, noninvasive and real-time molecular imaging in both living and nonviable systems at the microscale can be achieved.