Development of an Enzymatic Biosensor Using Glutamate Oxidase on Organic–Inorganic-Structured, Electrospun Nanofiber-Modified Electrodes for Monosodium Glutamate Detection

Abstract

Herein, dendrimer-modified montmorillonite (Mt)-decorated poly-Ɛ-caprolactone (PCL) and chitosan (CHIT)-based nanofibers were prepared. Mt was modified with a poly(amidoamine) generation 1 (PAMAMG1) dendrimer, and the obtained PAMAMG1–Mt was incorporated into the PCL–CHIT nanofiber’s structure. The PCL–CHIT/PAMAMG1–Mt nanofibers were conjugated with glutamate oxidase (GluOx) to design a bio-based detection system for monosodium glutamate (MSG). PAMAMG1–Mt was added to the PCL–CHIT backbone to provide a multipoint binding side to immobilize GluOx via covalent bonds. After the characterization of PCL–CHIT/PAMAMG1–Mt/GluOx, it was calibrated for MSG. The linear ranges were determined from 0.025 to 0.25 mM MSG using PCL–CHIT/Mt/GluOx and from 0.0025 to 0.175 mM MSG using PCL–CHIT/PAMAMG1–Mt/GluOx (with a detection limit of 7.019 µM for PCL–CHIT/Mt/GluOx and 1.045 µM for PCL–CHIT/PAMAMG1–Mt/GluOx). Finally, PCL–CHIT/PAMAMG1–Mt/GluOx was applied to analyze MSG content in tomato soup without interfering with the sample matrix, giving a recovery percentage of 103.125%. Hence, the nanofiber modification with dendrimer-intercalated Mt and GluOx conjugation onto the formed nanocomposite structures was performed, and the PCL–CHIT/PAMAMG1–Mt/GluOx system was successfully developed for MSG detection.

Electrospun Nanofibers including Organic/Inorganic Nanohybrids: Polystyrene- and Clay-Based Architectures in Immunosensor Preparation for Serum Amyloid A

“…The increment in the d range (3.29 Å) indicates that the alkylammonium cations were intercalated between the silicate layers. This result is compatible with that of our previous study on PAMAM with variable molecular weights [28][29][30]. The basal spacing value of interlayers increases with the chain length and also the molecular weight of PAMAM.…”

“…MMT with an organic molecule, PAMAM G3 , was modified according to a cationexchange process [28][29][30]. This process is based on the replacement of hydrated Na + ions in the interlayers of clay minerals with PAMAM G3 containing quaternary alkyl ammonium ions.…”

“…The large surface area of electrospun nanofibers are combined with clay, an ideal inorganic structure that can be used as an immobilization matrix for biomolecules owing to its high absorption and cation-exchange capacity (CEC) and well-dispersive nature. Polymer/inorganic hybrid electrospun nanofibers can be fabricated using different types of modified clays and polymers [28][29][30]. Montmorillonite (MMT), the most preferred clay in analytical applications, has been modified using dendrimers [28][29][30], folic acid [31], hexadecyl trimethyl ammonium chloride [32], and sodium dodecyl sulfonate [33], and transformed into nanofibers with poly(vinyl) alcohol (PVA), poly(caprolacton) (PCL), and Chit, among others [28][29][30].…”

“…Polymer/inorganic hybrid electrospun nanofibers can be fabricated using different types of modified clays and polymers [28][29][30]. Montmorillonite (MMT), the most preferred clay in analytical applications, has been modified using dendrimers [28][29][30], folic acid [31], hexadecyl trimethyl ammonium chloride [32], and sodium dodecyl sulfonate [33], and transformed into nanofibers with poly(vinyl) alcohol (PVA), poly(caprolacton) (PCL), and Chit, among others [28][29][30]. In our previous study, electrospun PVA nanofibers, including poly(amidoamine) generation 2 (PAMAM G2 )-modified MMTs, were fabricated for the covalent immobilization of pyranose oxidase to prepare stable enzymatic glucose biosensors [29].…”

“…In our previous study, electrospun PVA nanofibers, including poly(amidoamine) generation 2 (PAMAM G2 )-modified MMTs, were fabricated for the covalent immobilization of pyranose oxidase to prepare stable enzymatic glucose biosensors [29]. In other studies, electrospun polycaprolacton-Chit nanofibers, including PAMAM generation 0 (PAMAM G0 ) and PAMAM generation 1 (PAMAM G1 )-modified MMTs, were coated with arginylglycylaspartic acid peptide and glutamate oxidase to prepare cell adhesion platforms and monosodium glutamate biosensors, respectively [28,30]. Herein, the surface of polystyrene (PS) nanofibers, as well as PAMAM G3 -modified MMT, is considered to be an alternative to the routinely used ELISA platforms for the detection of SAA.…”