The Target Urine VOCs Biosensor for Genitourinary Malignancy Detection

Overview

Volatile organic compounds (VOCs) have grown due to their crucial role in transitioning from invasive to noninvasive cancer diagnostic methods. This study aimed to assess the feasibility of the metal oxide biosensor platform using urine VOCs for detecting genitourinary cancers. Five different commercially available semiconductor sensors were chosen to detect specific VOCs (methane, iso-butane, hydrogen, ethanol, hydrogen sulfide, ammonia, toluene, butane, propane, trimethylamine, and methyl-mercaptan). Changes in electrical resistance due to temperature variations from the voltage heater were examined to characterize VOC metabolism. Logistic regression and ROC analysis were employed to evaluate potential urine VOCs for genitourinary cancer determination.

Nowadays, the development of semiconductor metal oxide sensors allows the detection of VOCs from breath and urine by relying on the change of voltage and electrical resistance. The studies use electric current to evaporate VOCs and focus on the changes of evaporation at different temperatures. The results from the previous studies have shown that the changes in the voltage and electrical current resistance dynamics in the semiconductor metal oxide sensors indicate specific patterns that are specific to different types of VOCs. Therefore, this could transit the odor-fingerprint in biogas expression platform to the electrical expression platform due to the possibility of specific-disease VOC identification and the cost-effectiveness of the electrical expression platform when compared to SPME and GC-MS. This is a descriptive cohort study conducted among 64 subjects attending outpatient clinic at during August 2021 to July 2023. All the subjects were advised and voluntarily signed a consent form before participating in our study. The patients with the renal diseases and the normal subjects were prohibited to have strong odor food (such as tea, coffee, onion, garlic, shrimp paste, acacia, fermented fish, pakria, and celery, etc.) for at least 3 hours before the examination of urine VOCs and were prohibited alcohol intakes for more than 24 hours prior to the urine VOCs examination. The urine samples were collected for 20 mL in universal bottles and samples were classified as genitourinary (kidney/bladder/prostate) cancer or non-cancer or normal control after pathological examination of the biopsy specimens. The urine samples were kept at room temperature and taken to be analyzed with the semiconductor sensors within 30 minutes after the samples were collected. We selected five different commercially available semiconductor metal oxide sensors to detect all the targeted VOCs, which are methane, iso-butane, hydrogen, ethanol, hydrogen sulfide, ammonia, toluene, butane, propane, trimethylamine, methyl-mercaptan (manufactured by Figaro company). These are the types of VOCs which had been studied and were shown to be related to the malignant according to the literature. The detailed products and basic semiconductor circuits are available in the Figaro Product Information Manual (https://www.figarosensor.com/product/sensor/).