Label-Free in Situ Quantification of Drug in Living Cells at Micromolar Levels Using Infrared Spectroscopy

TY - JOUR

T1 - Label-Free in Situ Quantification of Drug in Living Cells at Micromolar Levels Using Infrared Spectroscopy

AU - Chan, Ka Lung Andrew

AU - Vieira Fale, Pedro L.

PY - 2014/12/2

Y1 - 2014/12/2

N2 - Quantifying the rate and the amount of drug entering live cells is an essential part of the medicine development process. Infrared spectroscopy is a label-free, chemically selective tool for analyzing the composition of live cells in culture that has the potential to quantify, in situ, the amount of drug entering living cells in a nondestructive manner, although its sensitivity is currently limited. This paper is the first to demonstrate in situ quantification of the cancer drug, fluorouracil, in live cells at a therapeutically relevant concentration using Fourier transform infrared spectroscopy. To achieve the required improvement in detection and quantitation limits of the IR measurement, two strategies were exploited. First, a sampling method called multibounce attenuated total reflection was used to optimize the signal while second, a long pass filter in combination with a mercury cadmium telluride detector was used to reduce the instrument noise. Using these novel adaptations, it was possible to quantify 20 μM of fluorouracil in cell culture medium using a standard FTIR instrument, while it was possible to quantify and measure the flux of fluorouracil in situ in living cells treated with an 80 μM drug.

AB - Quantifying the rate and the amount of drug entering live cells is an essential part of the medicine development process. Infrared spectroscopy is a label-free, chemically selective tool for analyzing the composition of live cells in culture that has the potential to quantify, in situ, the amount of drug entering living cells in a nondestructive manner, although its sensitivity is currently limited. This paper is the first to demonstrate in situ quantification of the cancer drug, fluorouracil, in live cells at a therapeutically relevant concentration using Fourier transform infrared spectroscopy. To achieve the required improvement in detection and quantitation limits of the IR measurement, two strategies were exploited. First, a sampling method called multibounce attenuated total reflection was used to optimize the signal while second, a long pass filter in combination with a mercury cadmium telluride detector was used to reduce the instrument noise. Using these novel adaptations, it was possible to quantify 20 μM of fluorouracil in cell culture medium using a standard FTIR instrument, while it was possible to quantify and measure the flux of fluorouracil in situ in living cells treated with an 80 μM drug.

KW - LIVE CELLS

KW - FT-IR spectroscopy

KW - DRUG

KW - CANCER CELLS

KW - Quantitative bioanalysis

U2 - 10.1021/ac503915c

DO - 10.1021/ac503915c

M3 - Article

SN - 0003-2700

VL - 86

SP - 11673

EP - 11679

JO - Analytical Chemistry

JF - Analytical Chemistry

IS - 23

ER -