Graphene-Doped Tin Oxide Nanofibers and Nanoribbons as Gas Sensors to Detect Biomarkers of Different Diseases through the Breath

Abstract

This work presents the development of tin oxide nanofibers (NFs) and nanoribbons (NRs) sensors with graphene as a dopant for the detection of volatile organic compounds (VOCs) corresponding to different chronic diseases (asthma, chronic obstructive pulmonary disease, cystic fibrosis or diabetes). This research aims to determine the ability of these sensors to differentiate between gas samples corresponding to healthy people and patients with a disease. The nanostructures were grown by electrospinning and deposited on silicon substrates with micro-heaters integrated. The morphology of NFs and NRs was characterized by Scanning Electron Microscopy (SEM). A gas line was assembled and programmed to measure a wide range of gases (ethanol, acetone, NO and CO) at different concentrations simulating human breath conditions. Measurements were made in the presence and absence of humidity to evaluate its effect. The sensors were able to differentiate between the concentrations corresponding to a healthy person and a patient with one of the selected diseases. These were sensitive to biomarkers such as acetone and ethanol at low operating temperatures (with responses above 35%). Furthermore, CO and NO response was at high temperatures (above 5%). The sensors had a rapid response, with times of 50 s and recovery periods of about 10 min.

Advanced wearable biosensors for the detection of body fluids and exhaled breath by graphene

“…Sanchez-Vicente et al developed an innovative sensor that can detect ethanol, acetone, NO, and CO in the breath, which could relate to many diseases such as chronic obstructive pulmonary disease, cystic fibrosis, asthma, and even diabetes (Fig. 9c ) [ 283 ]. The detection was carried out at 0% humidity as well as 50% humidity under which the following equation was implied to find the sensor’s performance: where R a and R represent the resistance at exposure to air and the gas, respectively.…”

“…c The silicon substrates with micro hot plates and the sensor response to various VOCs. Reprinted with permission from [ 283 ]. Copyright 2020 Multidisciplinary Digital Publishing Institute.…”

The State of the Art on Graphene-Based Sensors for Human Health Monitoring through Breath Biomarkers

“…The synthetic samples were prepared with known concentrations of acetone and ethanol, ranging between 0.5 and 4 ppm v , to simulate both healthy individuals and pathological volunteers. The developed system could successfully differentiate both groups with outstanding capacity, proving that the authors can now test it using real samples of exhaled air [139].…”

Paving the Way for a Green Transition in the Design of Sensors and Biosensors for the Detection of Volatile Organic Compounds (VOCs)

“…In recent years, scientific efforts have especially focused on the design of environmentally friendly sensors and biosensors for the sustainable diagnosis of cancer and diabetes. Moreover, some remarkable results have been also obtained in the diagnosis of asthma, chronic obstructive pulmonary disease, cystic fibrosis, liver cirrhosis and tuberculosis [ 181 , 182 , 183 , 184 , 185 ].…”