pH-responsive ratiometric photoacoustic imaging of polyaniline nanoparticle-coated needle for targeted cancer biopsy

Ayoung Choe; David Qin; Anthony M Yu; Euisuk Chung; Anamik Jhunjhunwala; Julian A Rose; Stanislav Y Emelianov

doi:10.1016/j.pacs.2023.100500

pH-responsive ratiometric photoacoustic imaging of polyaniline nanoparticle-coated needle for targeted cancer biopsy

Photoacoustics. 2023 Apr 26:31:100500. doi: 10.1016/j.pacs.2023.100500. eCollection 2023 Jun.

Authors

Ayoung Choe^{1

2}, David Qin¹, Anthony M Yu¹, Euisuk Chung², Anamik Jhunjhunwala¹, Julian A Rose¹, Stanislav Y Emelianov^{1

2}

Affiliations

¹ Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA 30332, USA.
² School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA.

Abstract

Cancer microenvironment exhibits lower pH compared to healthy tissues, a characteristic which can be exploited using a pH-responsive needle to increase the accuracy of cancer biopsy. A needle, coated with pH-responsive polyaniline (PANI) nanoparticles (PANI-needle), is developed for the minimally invasive and quantitative pH analysis of tissue based on ratiometric photoacoustic (PA) imaging. The ratiometric PA signal from the PANI-needle within the 850-700 nm wavelength range shows a linear response as pH changes from 7.5 to 6.5. Owing to the high surface area of nanostructured PANI, the PA signal of PANI-needle exhibits a fast and reversible response of less than a few seconds. In a tissue-mimicking hydrogel phantom composed of two regions with different pH, PA ratios of PANI-needle successfully differentiate the local pH. The PANI-needle coupled with ultrasound-guided PA imaging is a promising technology for detection of malignant tissue through quantitative pH analysis during needle biopsy.

Keywords: PH sensors; Photoacoustic contrast agents; Polyaniline nanoparticles; Ratiometric analysis.