title: In situ synthesis of cylindrical spongy polypyrrole doped protonated graphitic carbon nitride for cholesterol sensing application.
abstract: Herein, we demonstrate the exfoliation of bulk graphitic carbon nitrides (g-C3N4) into ultra-thin (~3.4nm) two-dimensional (2D) nanosheets and their functionalization with proton (g-C3N4H+). The layered semiconductor g-C3N4H+nanosheets were doped with cylindrical spongy shaped polypyrrole (CSPPy-g-C3N4H+) using chemical polymerization method. The as-prepared nanohybrid composite was utilized to fabricate cholesterol biosensors after immobilization of cholesterol oxidase (ChOx) at physiological pH. Large specific surface area and positive charge nature of CSPPy-g-C3N4H+composite has tendency to generate strong electrostatic attraction with negatively charged ChOx, and as a result they formed stable bionanohybrid composite with high enzyme loading. A detailed electrochemical characterization of as-fabricated biosensor electrode (ChOx-CSPPy-g-C3N4H+/GCE) exhibited high-sensitivity (645.7 µAmM-1cm-2) in wide-linear range of 0.02-5.0mM, low detection limit (8.0μM), fast response time (~3s), long-term stability, and good selectivity during cholesterol detection. To the best of our knowledge, this novel nanocomposite was utilized for the first time for cholesterol biosensor fabrication that resulted in high sensing performance. Hence, this approach opens a new prospective to utilize CSPPy-g-C3N4H+composite as cost-effective, biocompatible, eco-friendly, and superior electrocatalytic as well as electroconductive having great application potentials that could pave the ways to explore many other new sensors fabrication and biomedical applications.
authors.affiliation: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Division of Mechanical Design Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
authors.forename: Bishnu Kumar
authors.initials: BK
authors.lastname: Shrestha
authors.affiliation: School of Semiconductor and Chemical Engineering, Nanomaterials Processing Research, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
authors.forename: Rafiq
authors.initials: R
authors.lastname: Ahmad
authors.affiliation: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea.
authors.forename: Sita
authors.initials: S
authors.lastname: Shrestha
authors.affiliation: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Division of Mechanical Design Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea. Electronic address: biochan@jbnu.ac.kr.
authors.forename: Chan Hee
authors.initials: CH
authors.lastname: Park
authors.affiliation: Department of Bionanosystem Engineering, Graduate School, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea; Division of Mechanical Design Engineering, Chonbuk National University, 567 Baekje-daero, Deokjin-gu, Jeonju-si, Jeollabuk-do 54896, Republic of Korea. Electronic address: chskim@jbnu.ac.kr.
authors.forename: Cheol Sang
authors.initials: CS
authors.lastname: Kim
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002784:Cholesterol / Q000737:chemistry / Q000302:isolation & purification*; D002789:Cholesterol Oxidase / Q000737:chemistry; D055664:Electrochemical Techniques / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry; D006108:Graphite / Q000737:chemistry; D006801:Humans; D057230:Limit of Detection; D053761:Nanocomposites / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry; D009570:Nitriles / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011758:Pyrroles / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D037742:Nanotubes, Carbon; D009570:Nitriles; D011108:Polymers; D011758:Pyrroles; C067635:polypyrrole; C011206:cyanogen; D006108:Graphite; D002784:Cholesterol; D002789:Cholesterol Oxidase
keywords: Biocompatible; Carbon nitride; Cholesterol biosensor; Polypyrrole; Ultra-thin nanosheets