A pH-responsive photoacoustic imaging probe for tumor pH imaging in vivo based on polyaniline–bovine serum albumin

Abstract

Precise pH detection in tumors can guide the design of pH-responsive drugs and theranostic agents to improve treatment efficacy. However, most reported pH-responsive probes are fluorescent probes, for which in vivo application is limited by low probe penetration depth. In this study, a pH-responsive polyaniline–bovine serum albumin (BSA) probe was constructed for precise pH detection in tumors using photoacoustic imaging. The probe can be used to generate high-resolution images of deep biological tissues. The photoacoustic signal of the polyaniline–BSA probe exhibits a clear linear relationship with pH in the range of 5–6.8 both in vitro and in vivo, indicating that the probe is ideal for precise pH detection in most tumors. The polyaniline–BSA probe also exhibits satisfactory biocompatibility, low toxicity, fast response, and good reversibility. This work provides a useful in vivo pH detection probe for developing pH-responsive drugs and theranostic agents.