Disposable electrochemiluminescent biosensor for lactate determination in saliva

Abstract

An electrochemiluminescence-based disposable biosensor for lactate is characterized. The lactate recognition system is based on lactate oxidase (LOx) and the transduction system consists of luminol. All the needed reagents, luminol, LOx, BSA, electrolyte and buffer have been immobilized by a Methocel membrane placed on the working electrode of the screen-printed electrochemical cell. The measurement of the electrochemiluminescence (ECL) is made possible via a photocounting head when 50 microl of sample is placed into the screen-printed cell with a circular container containing the disposable sensing membrane. The compositions of the membrane and reaction conditions have been optimized to obtain adequate sensitivity. The disposable biosensor responds to lactate after 20 s when two 1 s pulses at 0.5 V are applied to obtain the analytical parameter, the ECL initial rate. The linearized double logarithmic dependence for lactate shows a dynamic range from 10(-5) to 5 x 10(-4) M with a detection limit of 5 x 10(-6) M and a sensor-to-sensor repeatability, as relative standard deviation, RSD, of 3.30% at the medium level of the range. The ECL disposable biosensor was applied to the analysis of lactate in human saliva as an alternative procedure for obtaining the lactate level in a non-invasive way. Interferences coming from components of saliva were studied and eliminated in a simple way that was easy to handle. The procedure was validated for use in human saliva, comparing the results against an enzymatic reference procedure. The proposed method is quick, inexpensive, selective and sensitive and uses conventional ECL instrumentation.

Applications of Electrochemiluminescence

“…H 2 O 2 was produced by enzymatic reaction of GOD, and ECL could be obtained by the reaction between luminol and H 2 O 2 for sensing glucose [69]. A FI optical fiber glucose and lactate biosensor [70][71][72] and a thin-film glucose ECL biosensor were also developed based on alcohol-free mesoporous molecular sieve silica modified electrode [73] and immobilization of GOD with MWNT/ Nafion film [74][75][76].…”

Properties and Customization of Sensor Materials for Biomedical Applications

“…Diagnostics, personal health, and related costs will also benefit from the introduction of sensors technology (5)(6)(7). In addition, with the introduction of Registration, Evaluation, Authorization, and Restriction of Chemical Substances (REACH) regulation, unraveling the cause-effect relationships in epidemiology studies will be of outmost importance to help establish reliable environmental policies aimed at protecting the health of individuals and communities (8)(9)(10). For instance, the effect of low concentration of toxic elements is seldom investigated as physicians do not have means to access the data (11).…”

Portable system for photodiode-based electrochemiluminescence measurement with improved limit of detection

“…The position of the electrode was fixed with two metacrylate holders that fit one inside the other and established the electrode position with respect to the PMT. This experimental setup has been described in earlier works[22][23].…”