Non-invasive in-situ blood electrolyte mineral analysis using a passive PPy bio-electronic sensor

• Main Author: Lanuza, Chiara Rosario Julia V.
• Format: text
• Language: English
• Published: Animo Repository 2022
• Subjects: Electrolytes; Blood flow—Measurement; Biosensors; Physics
• Online Access: https://animorepository.dlsu.edu.ph/etd_doctoral/1422; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=2470&context=etd_doctoral
• Institution: De La Salle University

This research is in response to the dire need to be able to measure vital blood electrolytes in real time: hence the development of a passive and inexpensive blood-electrolyte sensor array that can easily be integrated to present gadgets and readily available to the masses. Twenty-seven polypyrrole (PPy) films were fabricated using different dopants and synthesis conditions. Of these films, ten were chosen in the construction of ten sensors to detect blood potassium, sodium, chloride, bicarbonate, magnesium, and phosphate levels non-invasively, in-situ, and in real time. A clinical trial was performed on thirty subjects and the sensors' response was correlated to the actual blood electrolyte level as measured by a medical diagnostic laboratory. The sensors as a set, successfully measured both anion and cation blood electrolytes.The PPy/dopant 1-based sensors' response showed a high correlation to blood potassium and magnesium levels with Pearson's Correlation Coefficients (R) of 0.78 and 0.51 respectively. It also presented a moderate correlation to blood chloride levels with R=0.37. The computed PPY/dopant 1-based sensor activities for blood potassium, magnesium, and chloride levels were found to be 6.4 x 102 mV/mmo1-L-1. 5.9 x 103 mV/mmo1-L-1, and 3.1 x 102 mV/mmo1-L-1 respectively.The four sensors fabricated using PPy/dopant 2 films responded to blood potassium, blood chloride, and blood bicarbonate levels; all with high correlation. This demonstrated the sensors' consistency and repeatability in detecting certain electrolytes, It was further observed that co-doping PPy/dopant 3 enhanced the sensors' response to blood potassium and blood sodium levels.The PPy/dopant 4-based sensors' response showed high correlation to blood potassium levels (R=0.55) and low or no correlation to the other remaining blood electrolyte levels. This sensor also registered a higher sensitivity to blood potassium levels (1.3 x 103 mV/mmo1-L-1) as compared to that of PPy/dopant 2-based sensors (region of 9 x 102 mV/mmo1-L-1).Not all sensors showed versatility; in particular, the PPy/dopant 5 film-based sensor responded best only to blood phosphate (i.e. highly selective) and the sensor constructed using PPy/dopant 6 showed low correlation or no correlation to all blood electrolyte minerals tested.Based on the study's results, it was determined that the type of dopant used in synthesizing the PPy film played the greatest role in fine-tuning the bio-electronic sensors' selectivity and sensitivity. Thus, a bio-electronic sensor array can be designed using PPy films of varying dopants to measure different blood electrolyte levels.