Poly(Thionine)-Modified Screen-Printed Electrodes for CA 19-9 Detection and Its Properties in Raman Spectroscopy

Abstract

Polythionine (PTH) is an electroactive compound known for its excellent electron transfer capacity. It has stable and redox centers in its structure, and it can also be generated by electropolymerization of thionine (TH). Due to its properties, it has been used in a large number of applications, including the construction of electrochemical biosensors. In this work, PTH is explored for its ability to generate electrons, which allows it to act as an electrochemical probe in a biosensor that detects CA 19-9 on two different substrates, carbon and gold, using differential pulse voltammetry (DPV) as a reading technique in phosphate buffer (PhB). The analytical features of the resulting electrodes are given, showing linear ranges from 0.010 to 10 U/mL. The Raman spectra of PTH films on gold (substrates or nanostars) and carbon (substrates) are also presented and discussed as a potential use for SERS readings as complementary information to electrochemical data.

Liquid Redox Probe-Free Plastic Antibody Development for Malaria Biomarker Recognition

“…These are five known bands (D*, D, D″, G, and D′) in the first-order Raman spectrum and three bands (G*, 2D, and D+D′) in the second-order Raman spectrum that successfully interpret the Raman spectra. The D* band originates from the sp 3 orbital and is similar to the D* band observed in sp 3 -rich phases, disordered graphene oxide flakes, and powders . The D band represented arises from the defects and disorders in the carbon lattice and the double resonant processes near the K point of the Brillouin zone (BZ) boundary .…”

“…The D* band originates from the sp 3 orbital and is similar to the D* band observed in sp 3 -rich phases, 35 disordered graphene oxide flakes, and powders. 36 The D band represented arises from the defects and disorders in the carbon lattice and the double resonant processes near the K point of the Brillouin zone (BZ) boundary. 37 The G band represented the bond-stretching vibrations of sp 2 hybridization carbon atoms, expressing the C=C stretching of graphitic structures.…”

An electrochemically synthesized molecularly imprinted polymer for highly selective detection of breast cancer biomarker CA 15-3: a promising point-of-care biosensor

“… 45 The peak at around ∼1586 cm −1 is G band and is due to optical phonon mode with E 2g symmetry associated with an in-plane stretching of sp 2 bonded carbon atoms. 46 …”

“…45 The peak at around ∼1586 cm −1 is G band and is due to optical phonon mode with E 2g symmetry associated with an in-plane stretching of sp 2 bonded carbon atoms. 46 The peak at about 1356 cm −1 is referred to as the disorderinduced or D band and is associated with the A 1g symmetry breathing mode, which is associated with the oxidation of graphite and subsequent reduction of graphene oxide and signicantly alters the basal plane structure of graphene. 47 The degree of graphitization of a carbon material is generally characterized by the I D /I G value in the Raman spectra, where I G is the intensity of the G band corresponding to graphite and I D is the intensity of the D band corresponding to defects and disorder in the graphene oxide.…”

Carbon Inks-Based Screen-Printed Electrodes for Qualitative Analysis of Amino Acids

“…The assignment of the D and G peaks is straightforward for carbonous materials. The intense peak appearing at 1330 cm −1 called the D band is related to the presence of defects in the carbonous material, and the G band that appears at 1588 cm −1 is associated to in-plane vibration modes of sp 2 hybridized carbon atoms [ 37 , 38 , 39 ]. Additional characteristic features can be observed at higher wavenumbers: a third band so-called the 2D band peaking at 2663 cm −1 that is due to the second-order Raman scattering of the D band and a weak defect-activated Raman peak around 2903 cm −1 that is known as the D+G band and is associated with combination scattering [ 40 , 41 ].…”