Academic Journal
Polyhistidine-functionalized phosphorene-ZnO nanorods as an EGFET urea biosensor via enzymatically induced local pH modulation.
| Title: | Polyhistidine-functionalized phosphorene-ZnO nanorods as an EGFET urea biosensor via enzymatically induced local pH modulation. |
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| Authors: | A S; Department of Information and Communication Engineering, Anna University Regional Campus Coimbatore, Coimbatore, Tamil Nadu, India. Electronic address: srinivas.aucbe@gmail.com., R V; Department of Electrical and Electronics Engineering, Anna University Regional Campus, Coimbatore, Tamil Nadu, India. Electronic address: vb@aurcc.ac.in. |
| Source: | Talanta [Talanta] 2026 Aug 15; Vol. 306, pp. 129691. Date of Electronic Publication: 2026 Mar 27. |
| Publication Type: | Journal Article |
| Language: | English |
| Journal Info: | Publisher: Elsevier Country of Publication: Netherlands NLM ID: 2984816R Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1873-3573 (Electronic) Linking ISSN: 00399140 NLM ISO Abbreviation: Talanta Subsets: MEDLINE |
| Imprint Name(s): | Publication: Amsterdam : Elsevier Original Publication: Oxford : Pergamon Press |
| MeSH Terms: | Zinc Oxide*/chemistry , Biosensing Techniques*/methods , Biosensing Techniques*/instrumentation , Histidine*/chemistry , Nanotubes*/chemistry , Urea*/analysis , Urease*/chemistry , Urease*/metabolism , Transistors, Electronic*, Enzymes, Immobilized/chemistry ; Enzymes, Immobilized/metabolism ; Hydrogen-Ion Concentration ; Electrodes |
| Abstract: | A polyhistidine-functionalized phosphorene-ZnO (PolyHis-PP-ZnO) heterostructured electrode integrated into an extended-gate field-effect transistor (EGFET) platform is presented for potentiometric urea biosensing. Vertically aligned ZnO nanorods were hydrothermally grown on fluorine-doped tin oxide substrates and conformally coated with few-layer phosphorene to establish a conductive 1D/2D heterointerface. An in situ polyhistidine layer was subsequently introduced to provide imidazole-rich proton-active sites and Ni2+ coordination anchors for affinity-driven urease immobilization. Structural, spectroscopic, and impedance analyses confirmed strong Zn-P-N interfacial coupling, reduced charge-transfer resistance, and enhanced interfacial capacitance, supporting efficient signal transduction. Following urease functionalization, the device exhibited a logarithmic urea response over the 0.05-10mM range with a sensitivity of 55.2mV/dec(R2=0.995). The sensing mechanism arises from urease-catalysed hydrolysis of urea, which generates hydroxide ions and induces localized pH modulation at the electrode-electrolyte interface. This surface-potential variation is transduced through the EGFET architecture into measurable shifts in reference voltage. The biosensor demonstrated low hysteresis (∼7.4mV), minimal drift (∼0.50mV/h), high selectivity against common physiological interferents, and stable potentiometric response with minimal signal drift during continuous operation. The synergistic combination of phosphorene-mediated charge transport, PolyHis proton buffering, and Ni2+-imidazole affinity immobilization enables a robust and miniaturizable enzymatic transduction platform suitable for biochemical and physiological urea monitoring. (Copyright © 2026 Elsevier B.V. All rights reserved.) |
| Competing Interests: | Declaration of competing interest The authors declare no conflicts of interest regarding this manuscript. |
| Contributed Indexing: | Keywords: Extended-gate field-effect transistor (EGFET); Phosphorene-ZnO heterostructure; Polyhistidine functionalization; Urea biosensor |
| Substance Nomenclature: | SOI2LOH54Z (Zinc Oxide) 4QD397987E (Histidine) 26062-48-6 (polyhistidine) 8W8T17847W (Urea) EC 3.5.1.5 (Urease) 0 (Enzymes, Immobilized) |
| Entry Date(s): | Date Created: 20260328 Date Completed: 20260714 Latest Revision: 20260714 |
| Update Code: | 20260714 |
| DOI: | 10.1016/j.talanta.2026.129691 |
| PMID: | 41903386 |
| Database: | MEDLINE |
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