Application of a Novel Biosensor for Salivary Conductivity in Detecting Chronic Kidney Disease

Abstract

The prevalence of chronic kidney disease (CKD) is increasing, and it brings an enormous healthcare burden. The traditional measurement of kidney function needs invasive blood tests, which hinders the early detection and causes low awareness of CKD. We recently designed a device with miniaturized coplanar biosensing probes for measuring salivary conductivity at an extremely low volume (50 μL). Our preliminary data discovered that the salivary conductivity was significantly higher in the CKD patients. This cross-sectional study aims to validate the relationship between salivary conductivity and kidney function, represented by the estimated glomerular filtration rate (eGFR). We enrolled 214 adult participants with a mean age of 63.96 ± 13.53 years, of whom 33.2% were male. The prevalence rate of CKD, defined as eGFR < 60 mL/min/1.73 m2, is 11.2% in our study. By multivariate linear regression analyses, we found that salivary conductivity was positively related to age and fasting glucose but negatively associated with eGFR. We further divided subjects into low, medium, and high groups according to the tertials of salivary conductivity levels. There was a significant trend for an increment of CKD patients from low to high salivary conductivity groups (4.2% vs. 12.5% vs. 16.9%, p for trend: 0.016). The receiver operating characteristic (ROC) curves disclosed an excellent performance by using salivary conductivity combined with age, gender, and body weight to diagnose CKD (AUC equal to 0.8). The adjusted odds ratio of CKD is 2.66 (95% CI, 1.10–6.46) in subjects with high salivary conductivity levels. Overall, salivary conductivity can serve as a good surrogate marker of kidney function; this real-time, non-invasive, and easy-to-use portable biosensing device may be a reliable tool for screening CKD.

A novel microfluidic compact disc to investigate electrochemical property changes between artificial and real salivary samples mixed with mouthwashes using electrical impedance analysis

“…As a result, conductivity increases with frequency. The obtained values of conductivity at higher frequencies fully correspond to the values of salivary conductivity given in the literature, where lower values of conductivity can be considered values of 4.84 ± 1.01 μS/cm and higher values of 7.994 ± 1.02 μS/cm [ 26 ]. The value of conductance can be obtained by applying the following equations: G refers to the experimental conductance value, and R is defined as resistance.…”

“…In this series of research, it has been demonstrated that in dehydrated healthy adults, an increase in salivary conductivity was linked to an increase in serum and urinary osmolality. Furthermore, it has also been found that salivary conductivity and age had strong correlations [ 26 ]. In this case, reduced saliva secretion due to xerostomia or dry mouth syndrome will influence the saliva’s compositions and conductivity.…”

A Novel Salivary Sensor with Integrated Au Electrodes and Conductivity Meters for Screening of Diabetes

“…The temperature compensation through the MCU system allows the measurement signal to be obtained at 25 • C, and the result can be displayed on the OLED within 10 s (Figure 1D). Our device is highly reusable, as supported by previous research [29].…”

“…The portable device is easy-to-use and does not require specialized personnel to operate. Our initial data suggests a positive correlation between higher salivary conductivity and elevated fasting glucose levels, as well as an increased risk of developing chronic kidney disease [27][28][29]. However, further research is necessary to validate salivary conductivity as a reliable biomarker for diabetes.…”

Graphene Oxide-Magnetic Nanoparticles Loaded Polystyrene-Polydopamine Electrospun Nanofibers Based Nanocomposites for Immunosensing Application of C-Reactive Protein

“…The interference effects of BSA, urea, INS and SAA, which are some biological substances in saliva that may interfere with the PS/rGO-MNP-PDA/Anti-CRP immunosensor response developed for CRP detection, were investigated. The reference ranges of BSA (0.72–2.45 mg/mL) and urea (39–66 mg/dL) in saliva were determined according to the literature [ 69 , 70 ]. It was reported in the literature that SAA concentrations are generally between 20 and 50 mg/L for humans [ 71 ].…”