Real-time measurement of drug kinetics by diamond microelectrodes

Abstract

Real-time recording of the kinetics of systemically administered drugs in vivo may improve medical therapies. Nonetheless, conventional methods for drug detection require considerable analyte quantities and have poor sampling rates. Additionally, they cannot address how drug kinetics correlates with target function over time. Here, we describe a microsensing system equipped with two different sensors. One is a needle-type microsensor composed of boron-doped diamond, and the other is a glass microelectrode. We first tested bumetanide, a diuretic that can induce deafness. In the guinea-pig cochlea, our microsensing system measured, simultaneously and in real-time, changes in bumetanide concentration and the electrical activity underlying hearing. In the rat brain, we tracked the kinetics of the drug and neuronal activity. The system also detected the actions of the antiepileptic drug lamotrigine and its effect on neurons. Clearly, the local pharmacokinetics of bumetanide differed from that of lamotrigine. Finally, the diamond microsensor successfully detected the behavior of doxorubicin, an anticancer reagent, in the skin. Our microsensing system may detect pharmacological and physiological responses of other chemical compounds and contribute to advances in next-generation pharmacological interventions and on-site drug monitoring.