Sensitive Detection of Rosmarinic Acid Using Peptide-Modified Graphene Oxide Screen-Printed Carbon Electrode

Abstract

Peptides have been used as components in biological analysis and fabrication of novel sensors due to several reasons, including well-known synthesis protocols, diverse structures, and acting as highly selective substrates for enzymes. Bio-conjugation strategies can provide a simple and efficient way to convert peptide-analyte interaction information into a measurable signal, which can be further used for the manufacture of new peptide-based biosensors. This paper describes the sensitive properties of a peptide-modified graphene oxide screen-printed carbon electrode for accurate and sensitive detection of a natural polyphenol antioxidant compound, namely rosmarinic acid. Glutaraldehyde was chosen as the cross-linking agent because it is able to bind nonspecifically to the peptide. We demonstrated that the strong interaction between the immobilized peptide on the surface of the sensor and rosmarinic acid favors the addition of rosmarinic acid on the surface of the electrode, leading to an efficient preconcentration that determines a high sensitivity of the sensor for the detection of rosmarinic acid. The experimental conditions were optimized using different pH values and different amounts of peptide to modify the sensor surface, so that its analytical performances were optimal for rosmarinic acid detection. By using cyclic voltammetry (CV) as a detection method, a very low detection limit (0.0966 μM) and a vast linearity domain, ranging from 0.1 µM to 3.20 µM, were obtained. The novelty of this work is the development of a novel peptide-based sensor with improved performance characteristics for the quantification of rosmarinic acid in cosmetic products of complex composition. The FTIR method was used to validate the voltammetric method results.

Development of a Chemically Modified Sensor Based on a Pentapeptide and Its Application for Sensitive Detection of Verbascoside in Extra Virgin Olive Oil

“…Further preliminary analyses consisted of evaluating the electrochemical behavior of SPCE/GPHOX and SPCE/GPHOX-Pentapeptide in 0.1 M PBS at pH = 6.5. According to previous studies [ 23 , 60 , 61 ], the potential range in which a stable signal was obtained was from −0.4 to 1.0 V, proving to be optimal for the new peptide-based sensor described in the present study. The signal was stable after three cycles without interference or background noise, suggesting that there was no contamination of the active surface during the modification steps.…”

“…Taking into account our previous work [ 23 ], where it was demonstrated that the optimal pH value for electrochemical determinations at which a stable signal was obtained was 6.5, the determinations in this study were performed in solutions obtained by dissolving in 0.1 M PBS at pH 6.5. Moreover, in the same study, the optimal amount of peptide required for sensor modification was determined using different volumes of the peptide solution, demonstrating that the anodic peak was more intense and better defined when using a volume of 20 µL [ 23 ]. Therefore, the same volume of 20 µL of the pentapeptide solution was also used in the present study to obtain the modified sensor.…”

“…Peptides are short strings of amino acids, whereas amino acids are likewise the structure squares of proteins. It implies that peptides are little sisters of proteins [ 23 ]. Since these compounds do not often generate a signal that can be measured directly in response to a binding process, conjugation with a signal marker is an efficient method to transform the binding information into a measurable signal [ 24 ].…”

“…Since these compounds do not often generate a signal that can be measured directly in response to a binding process, conjugation with a signal marker is an efficient method to transform the binding information into a measurable signal [ 24 ]. Different materials, such as gold nanoparticles, have been used as signal markers [ 25 ], quantum dots [ 26 ], graphene [ 23 , 27 ], lanthanide chelates [ 28 ], and also electrochemical markers [ 29 ]. The use of peptides is a promising approach in view of the fact that these biomolecules can be used as biorecognition elements when connected with electrochemical sensors [ 30 ], representing an encouraging alternative for the study of both antioxidant activity and antioxidant compounds in different pharmaceutical or food products.…”

Recycling Nanoarchitectonics of Graphene Oxide from Carbon Fiber Reinforced Polymer by the Electrochemical Method

“…Actually, GO as a certain nanoarchitectonics, has been widely used by providing functional groups as active sites to connect small organic molecules, polymers, and other functional groups [ 20 , 21 , 22 , 23 , 24 ]. It has been used in applications relating to pharmaceutical carriers [ 24 , 25 , 26 ], the biological environment [ 27 , 28 ], energy fields [ 29 , 30 ], and nanoelectronics and optoelectronics [ 31 , 32 , 33 , 34 , 35 , 36 ], etc.…”