Nanocarbon Materials Modified with the Zinc Complex of Protoporphyrin IX, Recognized Antibiotics in Water Samples

Abstract

The complex between protoporphyrin IX and zinc was immobilized on nanocarbon paste and on nanodiamond paste to design two stochastic microsensors. The microsensors were used for the recognition and analysis of antibiotics: amoxicillin, ampicillin, and biotin in water samples. Stochastic sensors provided different signatures for the three antibiotics making possible their simultaneous recognition and assay in water samples. Low limits of determination 0.3 pg/mL for amoxicillin and ampicillin, and 0.21 pg/mL for biotin were obtained when nanocarbon paste was used, and 0.03 pg/mL for amoxicillin, 0.30 pg/mL for ampicillin, and 2.14 fg/mL for biotin were obtained when nanodiamond paste was used. Recoveries higher than 99.32 % with RSD lower than 1.00 % were obtained for the assay of the antibiotics in water samples.

Disposable Stochastic Sensor Based on Deposition of a Nanolayer of Silver on Silk for Molecular Recognition of Specific Biomarkers

“…Response characteristics of the disposabe stochastic sensors.-The response of the disposable stochastic sensors was based on channel conductivity. [1][2][3][4] The sensing mechanism takes place in two steps: (1) molecular recognition step (qualitative analysis takes place)-since entering the channel, the analyte blocks the channel and the current drops to zero for a certain time (until the entire molecule enter the channel) called the signature of the analyte (found in the diagrams as t off ); (2) analysis step (quantitative analysis takes place)-the analyte binds the internal channel wall and undergo redox process for a certain time-found in the diagrams as t on , which is correlated with the concentration of the analyte (Scheme 1, Fig. 5).…”

“…5) while the t on corresponding values found in the diagrams recorded for the biological samples (Fig. 5) were used for the quantitative determination of the analites accordingly with the equation: [1][2][3][4] t a b Conc 1 .…”

“…The utilization of the nanostructures on the active surfaces of the electrochemical sensors facilitated also the stochastic response of the sensors-a very powerful class of sensors due to its capacity of performing multianalyte detection because they are able to perform qualitative and quantitative analysis. [1][2][3][4] p53, CEA and CA19-9, are biomarkers used for the early detection as well as for follow up of the efficiency of treatment in different types of cancer, such as gastrointestinal cancer, pancreas cancer, colorectal cancer, and glioblastoma. Glioblastoma (GBM) represents one of the most frequent types of primary tumors of glioma in human brain.…”