Covalent immobilization of acetylcholinesterase on a novel polyacrylic acid‐based nanofiber membrane

Abstract

In this study, polyacrylic acid‐based nanofiber (NF) membrane was prepared via electrospinning method. Acetylcholinesterase (AChE) from Electrophorus electricus was covalently immobilized onto polyacrylic acid‐based NF membrane by demonstrating efficient enzyme immobilization, and immobilization capacity of polymer membranes was found to be 0.4 mg/g. The novel NF membrane was synthesized via thermally activated surface reconstruction, and activation with carbonyldiimidazole upon electrospinning. The morphology of the polyacrylic acid‐based membrane was investigated by scanning electron microscopy, Fourier Transform Infrared Spectroscopy, and thermogravimetric analysis. The effect of temperature and pH on enzyme activity was investigated and maxima activities for free and immobilized enzyme were observed at 30 and 35°C, and pH 7.4 and 8.0, respectively. The effect of 1 mM Mn2+, Ni2+, Cu2+, Zn2+, Mg2+, Ca2+ ions on the stability of the immobilized AChE was also investigated. According to the Michaelis–Menten plot, AChE possessed a lower affinity to acetylthiocholine iodide after immobilization, and the Michaelis–Menten constant of immobilized and free AChE were found to be 0.5008 and 0.4733 mM, respectively. The immobilized AChE demonstrated satisfactory reusability, and even after 10 consecutive activity assay runs, AChE maintained ca. 87% of its initial activity. Free enzyme lost its activity completely within 60 days, while the immobilized enzyme retained approximately 70% of the initial activity under the same storage time. The favorable reusability of immobilized AChE enables the support to be employable to develop the AChE‐based biosensors.

Zn2+‐Doped PVA Composite Electrospun Nanofiber for Upgrading of Enzymatic Properties of Acetylcholinesterase**

“…immobilized AChE on polyacrylic acid-based nanofiber and they stated that the optimum pH values for free AChE and immobilized AChE was 7.5 and 8.0, respectively. [38] Moradzadegan et al found AChE immobilized PVA/bovine serum albumin nanofibers and they didn't observe alteration the optimum pH values after the immobilization process. [36] The enzyme stability is affected by pH changes.…”

“…Çakıroğlu et al immobilized AChE onto polyacrylic acid/based nanofiber membrane and the optimal temperature for AChE was 30°C while it was 35°C for immobilized AChE. [38] Ebadi et al prepared AChE immobilized polyacrylic acid/multi-walled carbon nanotube nanofiber the optimum temperature values of free AChE and immbolizied AChE was 40 and 45°C, respectively. [39] Both free and immobilized AChEs were incubated for 1 h at different temperatures (30-60°C) to determine the effect of temperature on free AChE and immobilized AChE stability.…”

“…Çakıroğlu et al. immobilized AChE onto polyacrylic acid/based nanofiber membrane and the optimal temperature for AChE was 30 °C while it was 35 °C for immobilized AChE [38] . Ebadi et al.…”

“…Çakıroğlu et al. immobilized AChE on polyacrylic acid‐based nanofiber and they stated that the optimum pH values for free AChE and immobilized AChE was 7.5 and 8.0, respectively [38] . Moradzadegan et al.…”

Preparation and antimicrobial properties of LL‐37 peptide immobilized lignin/caprolactone polymer film

“…Polymeric materials with antimicrobial activity are used in many fields, particularly in medical devices technology, drug delivery systems, health care products and hygienic applications 1‐9 . One particular approach for therapeutic applications is the use of polymeric carriers or polymer active substance conjugate systems.…”