Acoustogenic Probes: A Demonstration to Introduce the Photoacoustic Effect via Analyte Sensing

Abstract

Photoacoustic imaging is a state-of-the-art technique that combines light excitation with ultrasound generation via the photoacoustic effect. Since sound waves at clinically relevant frequencies undergo minimal perturbation as they pass through the body, photoacoustic imaging is ideal for deep-tissue imaging applications in vivo. Despite its utility in the biomedical field, it is unlikely that undergraduate students will ever experience this technology firsthand in a classroom setting owing to the delicate and expensive nature of the instrumentation. Likewise, students will not be exposed to acoustogenic probes, which are specialized chemicals designed to detect biologically relevant analytes using photoacoustic imaging. With the goal of introducing new chemical analysis and imaging techniques to the undergraduate chemistry curricula, we present a simple and inexpensive setup (all materials were purchased for less than $48 USD) to demonstrate the photoacoustic effect through analyte sensing.

Activity-Based Sensing for Chemistry-Enabled Biology: Illuminating Principles, Probes, and Prospects for Boronate Reagents for Studying Hydrogen Peroxide

“…Photoacoustic (PA) imaging has garnered significant interest for in vivo imaging applications as it utilizes the detection of sound via probe excitation with longer wavelength deeper penetrating light . Acoustic detection enables depth penetration at centimeter length scales as sound scatters significantly less than emitted light in biological tissues. , Photoacoustic probes are generally designed to minimize nonradiative decay processes thereby ensuring the majority of energy loss upon irradiation results in the generation of heat as opposed to fluorescence emission. The increase in temperature causes thermoelastic expansion in the surrounding tissues and the pressure changes result in the generation of sound waves which provide the image contrast .…”

A Fluorometer-Free Experimental Course for Fluorescence Analysis Based on Smartphone and Image/Data-Processing Software Using a Synthetic Sensor

“…Quantitative sensing technologies play an essential role in scientific research and modern chemical analysis. − Among these technologies, fluorescence analysis is characterized by high sensitivity and great simplicity, making it widely used for the quantification of heavy metal ions, warfare agents, biomolecules, etc. − Their fluorescence intensity increases or decreases after reaction with the target analyte, thus allowing us to obtain the concentration of target analyte by calculating the variation of fluorescence intensity. Several courses have been developed to enhance students’ understanding of fluorescence analysis and have shown significant results. , However, a fluorometer is generally required to measure the value of fluorescence intensity, which poses certain challenges in undergraduate teaching.…”

Demonstration of Acetylene–Air Flame by Hydrolysis of Calcium Carbide to Rid Blind Beliefs and Misconceptions Regarding Purported Water Lit Lamp

“…Hydrolysis of calcium carbide to liberate the flammable acetylene gas has been reported in different contexts. − Herein formation of the visually attractive acetylene–air flame by hydrolysis of calcium carbide to rid blind beliefs and misconceptions regarding the purported water lit lamp has been demonstrated. Many such demonstrations and activities underlying chemistry principles have been hitherto studied to enthuse students in the subject. − From ancient times alchemists and magicians have been using chemistry principles pseudoscientifically in their ventures . Chemistry has enthralling tenets and magnificent applications that have immensely benefited mankind, but some of its visual manifestations being covert to decipher for the layperson are many a times perniciously exploited by some.…”