Microwave sensing of pM concentration of Insulin in buffer solution using WGM-DR

Abstract

In this paper we describe a Whispering gallery mode (WGE 800 ) dielectric resonator method with a cheap polycarbonate sample holding disk for sensing variation in picomolar (pM) concentration of Insulin in hepes buffer solution. For investigation of pM concentration Insulin solution mainly three different volumes i.e. 0.4, 0.8 and 6.4 microliter volume of sample solutions loaded on sample holding disk (SHD) and analyzed. Obtained results shows that calculated loss tangent of solution is sensitive to variation in pM concentration of Insulin with no shift in frequency. Moreover, small response time, low sample volume and its ability to sense losses in pM concentration of Insulin in liquid medium makes this method ideal insulin biosensor for medical diagnostic purpose.

NiO Nanoparticles for Electrochemical Insulin Detection

“…The electroanalytical properties of the modified electrode were compared with other electrode modifications from the literature (Table 1). As can be seen, the LOD of our prepared electrode is comparable with other electrodes mentioned in the literature [21,[26][27][28], and other methods used for insulin determination [9,10]. The huge advantage of our sensor in comparison with the mentioned electrode and methods is its simple and rapid preparation, high sensitivity (7.06 µA.µM −1 ), and fast current response (less then 1 s).…”

“…Therefore, it is necessary to focus on the development of a fast, inexpensive, accurate, and reliable method for direct insulin determination. Currently, various methods like surface-enhanced Raman spectroscopy [9], microwave sensing [10], etc., are known for insulin determination. The major techniques of insulin sensing can be generally categorized into four main groups: immunoassay, chromatographic methods, optical methods, and electrochemical methods.…”

Understanding the decay of proteins: A method to study time dependent response of pM concentration of insulin at microwave frequencies

“…Thus, by evaluating these properties it is possible to identify the activity period of any biological material in vitro . In the present study real and imaginary permittivity of different insulin concentrations in Hepes buffer solution was calculated by using the cavity perturbation method [11], [12], [17]. For calculating real and imaginary part of permittivity of solution we have used following equations presented in detail in Ref.…”

“…To study the biological activity of picomolar concentration of biomolecule in a liquid, the method must be very sensitive to ultra small changes. Whispering gallery mode (WGM) in dielectric resonator (DR) is well known to have high sensitivity and high Q factor and have been used for various sensing applications [11], [12], [13], [14], [15]. In the present study a composite single crystal sapphire DR with a disposable polycarbonate sample holding disk (SHD) is used to study the activity of pM concentration of insulin 25 millimolar (mM) Hepes buffer solution at 17 GHz microwave frequency for WGE 800 mode.…”