New Uses for the Personal Glucose Meter: Detection of Nucleic Acid Biomarkers for Prostate Cancer Screening.

Clara Abardía-Serrano,Noemí De-Los-Santos-Álvarez,Rebeca Miranda-Castro,María Jesús Lobo-Castañón

doi:10.3390/s20195514

Abstract

A personal glucose meter (PGM)-based method for quantitative detection of a urinary nucleic acid biomarker in prostate cancer screening, the so-called PCA3, is reported herein. A sandwich-type genoassay is conducted on magnetic beads to collect the target from the sample by specific hybridization, making the assay appropriate for PCA3 detection in biological fluids. The success of the method hinges on the use of alkaline phosphatase (ALP) to link the amount of nucleic acid biomarker to the generation of glucose. In particular, specifically attached ALP molecules hydrolyze D-glucose-1-phosphate into D-glucose, thus enabling the amplification of the recorded signal on the personal glucose meter. The developed genoassay exhibits good sensitivity (3.3 ± 0.2 mg glucose dL−1 pM−1) for PCA3, with a dynamic range of 5 to 100 pM and a quantification limit of 5 pM. Likewise, it facilitates point-of-care testing of nucleic acid biomarkers by using off-the-shelf PGM instead of complex instrumentation involved in traditional laboratory-based tests.

Highlights

Analyses at the point of need have aroused great interest in clinical diagnosis as well as in other areas such as food safety, environmental monitoring, or quality control due to their rapidity, portability, low cost, and easy use
We initially evaluated β-galactosidase (β-Galac) as a glucose-generating enzyme alternative to invertase that, to the best of our knowledge, has not been assessed for such a purpose so far. β-Galactosidase catalyzes the hydrolysis of lactose into galactose and glucose, whose concentration could be detected with the personal glucose meter (PGM)
Instead of developing an entire platform for nucleic acid biomarker detection, we have focused on transforming the widely used personal glucose meter into an electrochemical transducer of hybridization events, by introducing alkaline phosphatase onto magnetic beads bearing the specific duplex for converting D-glucose-1-phosphate into D-glucose

Summary

Introduction

Analyses at the point of need have aroused great interest in clinical diagnosis as well as in other areas such as food safety, environmental monitoring, or quality control due to their rapidity, portability, low cost, and easy use. In the case of healthcare, they are usually referred to as point-of-care or POC tests, which comprise diagnostic tests conducted out of the clinical laboratory and closer to the patient, by unskilled personnel or even the patients themselves [1]. These tests are generally designed for the detection of a certain target and they have to travel a long and expensive road before they are placed on the market, which limits the appearance of new devices for other targets. Notable in this category are pregnancy tests, which detect the human

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