Electrochemical Biosensor Development: Experimental and Computational Approaches Using Cu(I)-Catalysis and Click Chemistry
Author
Amini, Marzia
Term
4. semester
Education
Publication year
2025
Submitted on
2025-03-03
Abstract
Denne afhandling undersøger, hvordan elektrokemiske biosensorer kan gøres mere specifikke og effektive ved at udvikle og optimere funktionalisering af skærmprintede guldelektroder (SPGE’er) med enzymer og antistoffer, herunder en ny strategi baseret på klik-kemi katalyseret af Cu(I). Tre tilgange blev testet med cyklisk voltammetri, elektrokemisk impedansspektroskopi og chronoamperometri samt understøttende COMSOL Multiphysics-simuleringer. I Metode 1 blev SPGE’er funktionaliseret med MUA, HRP og Strep-HRP; elektrokemiske målinger bekræftede lagdannelse og enzymbinding, men uspecifik binding gjorde detektionssignalerne upålidelige. Metode 2 forbedrede specificiteten ved kovalent immobilisering af BAM1676-antistoffer på MUA-lag, hvilket gav koncentrationsafhængige ændringer i ladningstransfermodstand og øget følsomhed i chronoamperometri. Metode 3 introducerede en ny klik-kemiprotokol, hvor chronoamperometri påviste specifik Strep-HRP-binding; metoden vurderes lovende, men kræver yderligere optimering og robusthedstest. En praktisk udfordring var genbrug af SPGE’er, hvor ydeevnen faldt over flere målinger—særligt i Metode 3, hvor CV-signalet var omkring 50 % lavere end i Metode 1. 3D-modeller af redoxprocesser på bare og funktionaliserede elektroder reproducerede eksperimentelle CV-data og fremhævede steriske effekter af selvorganiserede monolag, enzymer og antistoffer på elektronoverførsel; resultaterne giver et grundlag for at optimere elektrodeafstand og sensordesign og kan udvides til systemer med flere arbejdselektroder.
This thesis explores how to make electrochemical biosensors more specific and effective by developing and optimizing the functionalization of screen-printed gold electrodes (SPGEs) with enzymes and antibodies, including a new Cu(I)-catalyzed click-chemistry strategy. Three approaches were evaluated using cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry, supported by COMSOL Multiphysics simulations. In Method 1, SPGEs were functionalized with MUA, HRP, and Strep-HRP; electrochemical measurements confirmed layer formation and enzyme binding, but non-specific binding limited the reliability of detection. Method 2 improved specificity by covalently immobilizing BAM1676 antibodies on MUA layers, yielding concentration-dependent changes in charge-transfer resistance and enhanced sensitivity in chronoamperometry. Method 3 introduced a new click-chemistry protocol, where chronoamperometry indicated specific Strep-HRP binding; the approach is promising but requires further optimization and robustness testing. A practical challenge across methods was electrode reuse, with performance degrading over repeated measurements—particularly in Method 3, where CV signals were about 50% lower than in Method 1. 3D models of redox processes at bare and functionalized electrodes reproduced experimental cyclic voltammetry and highlighted steric effects of self-assembled monolayers, enzymes, and antibodies on electron transfer; these insights provide a basis for optimizing electrode spacing and sensor design and can be extended to systems with multiple working electrodes.
[This summary has been generated with the help of AI directly from the project (PDF)]
Documents