Library · Signals, sensing & imaging
What Electrochemical Biosensors got wrong, from 30 theses
Summary written by a model from the records below: Across these thesis records, electrochemical biosensor platforms frequently face performance limitations stemming from electrode degradation, matrix interference, and unreliable surface functionalization. Developers also encounter poor operational stability during continuous sensing and lower detection sensitivity compared to established analytical baselines. These records come from graduate theses, 2021 to 2025, each labeled with its degree where the repository states it, and each links to its thesis. They were extracted by language models reading the full text, so treat each as a lead to read, not a verdict.
Plus 8 problems the authors left open, listed at the end.
Failure modes, by theses reporting them
Select a mode to jump to its records.
Surface functionalization and coating techniques lead to poor adhesion, uneven films, and signal loss
Physisorption, dip-coating, and drop-casting methods often result in random protein orientation, detached biomolecules, or uneven films that bleed into porous substrates. These preparation and preservation coatings cause severe signal attenuation, active site blockage, or failure to improve target analyte sensitivity over unmodified baselines.
Tried and failed
direct enzyme physical adsorption on noble metals applied to electrochemical biosensor electrodes. Outcome: worse than baseline. Reason: produced sensors with lower sensitivity compared to carbon screen-printed electrodes
Hardware and Software Interfaces Design for Multi-Panel Electrochemical Sensors · EPFL · PhD
Tried and failed
high molecular weight polymer preservation coating applied to electrochemical biosensor surface storage. Reason: incomplete polymer film dissolution during washing led to severe signal attenuation
Engineering DNA-based electrochemical diagnostics for translational applications · MIT · PhD
Considered and rejected
Considered and rejected: LOx-based hydrogel recipe formulation was rejected for ChOx biosensors because it lacked sufficient viscosity to reliably coat the electrode needle tip.
Development of a microfluidic biosensing system for real-time monitoring of acetylcholinesterase activity · Imperial · PhD
Tried and failed
NHS-ester functionalized graphene covalent surface immobilization applied to nucleic acid electrochemical sensing. Outcome: no signal. Reason: non-specific probe and target adsorption prevented discrimination between complementary and non-complementary sequences
Development of electrochemical sensors for nucleic acid biomarkers · Imperial · PhD
Tried and failed
passive electrostatic adsorption for protein immobilization applied to biosensor surface functionalization. Outcome: unstable. Reason: random molecular orientation and detachment caused by buffers and surfactants led to poor adhesion and low signal
Capillary-driven Microfluidic Biosensing Platforms for Digital Biomolecule Detection · Texas Tech · PhD
Tried and failed
polyurethane dip-coating with volatile solvent applied to enzymatic electrochemical biosensors. Outcome: unstable. Reason: rapid solvent evaporation caused uncontrolled response shifts and excessive active site blocking
Development of a microfluidic biosensing system for real-time monitoring of acetylcholinesterase activity · Imperial · PhD
Tried and failed
manual dispensing and drop-casting of conductive inks applied to fabricating electrochemical sensors on flexible substrates. Outcome: unstable. Reason: produced uneven, non-reproducible electrode films with polymer ink bleeding into porous substrates
Plant-on-a-chip: monitoring chemical responses in living plants with printed sensors · Imperial · PhD
Tried and failed
amino acid surface modification applied to electrochemical carbon electrode sensitivity enhancement. Outcome: worse than baseline. Reason: did not significantly improve target analyte sensitivity compared to standard electrode overoxidation alone
Optimization of in vivo electrochemical detection of neurotransmitters and application to neurological pathologies · Imperial · PhD
Biological matrix components and electroactive interferents disrupt sensor selectivity and suppress signals
Complex matrices such as human serum, plasma, and industrial media contain proteins and interferents that cause biofouling and suppress electrochemical signals. Unmediated sensing configurations also suffer from cross-detection of non-target species and interference from fluctuating dissolved oxygen concentrations.
Tried and failed
electrochemical pseudo-peroxidase sensing with solid oxidants applied to cell-free hemoglobin in human plasma. Outcome: no signal. Reason: matrix interference from complex plasma proteins prevented stable catalytic current and ruined sensitivity
Development of an electrochemical sensor for measuring haemolysis products in urine · Imperial · PhD
Tried and failed
omitting wash steps in electrochemical immunoassay applied to protein biomarker detection in serum. Outcome: no signal. Reason: residual serum at 0.5% or higher suppressed the galvanic exchange electrochemical signal
The development of a metalloimmunoassay for the detection of NT-proBNP · UT Austin · PhD
Considered and rejected
Considered and rejected: Direct electrochemical lactate oxidation without enzyme mediation due to biofouling, low selectivity, and interferent sensitivity.
MICROFABRICATED DEVICES FOR IN-VIVO SENSING FOR MITOCHONDRIAL ASSESSMENT · Penn · PhD
Considered and rejected
Considered and rejected: Rejected Pt-based microelectrode chemical biosensors for choline detection due to non-specific cross-detection of dopamine.
Probing presynaptic regulation of dopamine release in health and disease · Oxford · PhD
Lost to a baseline
Aptamer sensor signal detection threshold of MN19-SITS in complex matrix (0.034 ± 0.003 µM) was higher than in Tris buffer (0.024 ± 0.002 µM)
Studying the Structural Dynamics and Aptamer-Ligand Interactions in the Cocaine-Binding Aptamer through Fluorescence Spectroscopy · York University · PhD
Aggressive operating environments, harsh cleaning, and electrical stress degrade sensor electrodes
Exposure to chloride-containing electrolytes, harsh piranha cleaning solutions, or stripping cycles corrodes thin films, integrated silver reference electrodes, and chromium adhesion layers. In addition, elevated redox probe concentrations during impedance measurements can induce electrical burnout and degrade delicate microscale working surfaces.
Tried and failed
electrochemical measurement using gold interdigitated microelectrodes applied to chloride-containing organic electrolyte solutions. Outcome: unstable. Reason: the electrolyte etched and oxidized the gold electrodes under oxidizing potentials
To Cleave or Not To Cleave: Side-Chain Design in Dioxythiophene Polymers · Georgia Tech · PhD
Tried and failed
electroless nickel immersion gold electrodes applied to electrochemical sensing in chloride electrolyte. Outcome: unstable. Reason: severe electrochemical degradation and parasitic redox currents occurred in chloride-containing media
A graphene chemosensor lab-on-a-PCB platform for multi-analyte detection · Imperial · PhD
Tried and failed
Electron beam deposited chromium gold electrodes applied to electrochemical microfluidic sensing. Outcome: unstable. Reason: chromium adhesion layer oxidised under negative pre-deposition potential causing electrode corrosion and detachment
Design and Fabrication of Microfluidic Electrochemical Sensor for Lead Detection in Drinking Water · York University · Master's
Tried and failed
metal electrodeposition and stripping calibration applied to electrochemical quartz crystal microbalance sensors. Outcome: unstable. Reason: residual deposited metal or substrate stripping degraded subsequent electrochemical measurement surfaces
Design and evaluation of mixed ionic/electronic conducting polymers for energy storage devices and organic electrochemical transistors · Imperial · PhD
Considered and rejected
Considered and rejected: Conductive plastic-encased sensor electrodes were chosen over exposed metallic electrodes to prevent oxidation/corrosion, though the author notes this likely diminished MEC direct electron transfer benefits.
Enhancement of Biogas Production During Start-Up Operations of the Anaerobic Digestion of Wastewater Sludge · Queen's University · Master's
Signal transduction and molecular switching mechanisms fail to produce measurable redox current changes
Bead-bound nanoparticles and conformational aptamer switches often fail to produce detectable current modulations because of poor electrical contact or minimal label displacement. Catalytic competition from metallic substrates and kinetics dominated by mass transport also prevent signal amplification despite increases in enzyme concentrations.
Tried and failed
direct electrochemical oxidation of bead-bound nanoparticles applied to electrochemical immunoassay detection. Outcome: no signal. Reason: nanoparticles lacked direct electrical contact with the electrode surface
The development of a metalloimmunoassay for the detection of NT-proBNP · UT Austin · PhD
Tried and failed
molecular beacon hybridization without enzymatic cleavage applied to electrochemical nucleic acid biosensors. Outcome: no signal. Reason: hybridization alone induced insufficient redox label displacement, producing a non-statistically significant signal change
Engineering DNA-based electrochemical diagnostics for translational applications · MIT · PhD
Tried and failed
redox-labelled aptamer electrochemical conformational switching sensor applied to C-reactive protein detection. Outcome: no signal. Reason: lack of measurable redox current modulation between target-bound and unbound aptamer conformations across electrochemical modalities
Electrochemical biosensors for continuous infection monitoring and early detection of sepsis · Imperial · PhD
Tried and failed
increasing restriction enzyme concentration applied to electrochemical DNA biosensor cleavage. Outcome: no signal. Reason: higher enzyme concentration did not produce statistically significant cleavage-induced signal change
Engineering DNA-based electrochemical diagnostics for translational applications · MIT · PhD
Tried and failed
enzymatic metallization on gold microelectrodes applied to impedance biosensor signal amplification. Outcome: no signal. Reason: Gold substrate catalytically competed with horseradish peroxidase, depleting silver deposition between electrodes
Single-Cell Impedance Cytometry for the Control of Single-Cell Electroporation in a Flow-Through Device · Georgia Tech · PhD
Tried and failed
estimating heterogeneous rate constants directly from charge-transfer resistance applied to film-covered electrochemical sensors. Outcome: did not generalise. Reason: film thickness, diffusion coefficient, and analyte solubility confound the direct mapping between resistance and kinetic rate constants
Biofouling of indwelling electrochemical sensors · Imperial · PhD
Continuous operation and dry storage cause severe baseline drift and loss of sensor sensitivity
Flow-through systems, in-line bioreactor monitors, and field-effect transistor platforms suffer from temporal baseline drift and inconsistent readings across measurement cycles. In addition, enzyme biosensors experience rapid activity loss within days when subjected to dry storage conditions.
Tried and failed
continuous flow-through electrochemical metabolite sensing applied to bioreactor cell culture monitoring. Reason: sensors suffered from measurement inaccuracy and inconsistency during continuous operation
Digital Twin Design and Autonomous Control of Bioreactor Systems for Human Immune Cell Expansion · Georgia Tech · PhD
Tried and failed
constant-current field-effect transistor biosensing applied to protein biomarker detection in buffer. Outcome: unstable. Reason: sensor instability prevented reproducibility across consecutive measurement trials
Biomarkers in Interstitial Fluid: From Screening to Sensor Development · EPFL · PhD
Tried and failed
in-line electrochemical enzymatic metabolite sensing applied to bioreactor cell culture monitoring. Outcome: unstable. Reason: sensors lacked signal stability and did not reliably match at-line reference measurements
Process development and process analytical technology integration for cell therapy manufacturing · Georgia Tech · PhD
Tried and failed
Dry storage of crosslinked enzyme biosensors applied to lactate electrochemical biosensing. Outcome: unstable. Reason: Rapid loss of enzyme response within days at room temperature and one week at 4°C
Biosensors for exhaled breath condensate analysis · Imperial · PhD
Considered and rejected
Considered and rejected: Rejected direct RT-LAMP electrochemical sensing (ISFET) for immediate deployment due to unresolved challenges with reagent application, heat transfer, and sensor drift.
Understanding dengue transmission in remote settings through innovative and integrated diagnostic and surveillance systems · Imperial · PhD
Tried and failed
drop-cast ion-selective membranes on CMOS ISFETs applied to continuous multi-ion electrochemical sensing. Outcome: unstable. Reason: Severe temporal baseline drift and rapid loss of sensor sensitivity over continuous calibration cycles
A portable microfluidic electrochemical sensing platform for the real-time detection of clinical neurochemical markers · Imperial · PhD
Novel biosensor configurations fail to match the analytical sensitivity of standard reference methods
Newly developed electrochemical sensors, aptasensors, and immunosensors exhibit higher detection limits and lower sensitivity than commercial enzyme-linked assays and needle electrode baselines. Incomplete surface exposure of conductive materials and monometallic framework limitations further reduce analytical response relative to optimized alternatives.
Lost to a baseline
Enzyme-based needle electrode (Yonemori et al. 2009) achieved a higher sensitivity (3.10 a.u./mg.dl⁻¹) than this work's glucose sensor (0.0354 a.u./mg.dl⁻¹).
Opto-chemical biosensor development, and analytics for point-of-care applications · Iowa State · PhD
Lost to a baseline
Proposed aptasensor limit of detection (100 pg/mL) was beaten by commercial/conventional ELISA (0.78 pg/mL) and electrochemical immunosensors (down to 0.036 pg/mL).
Patient-centred technologies targeting genetics, activity, and metabolism for lifestyle and healthcare personalisation · Imperial · PhD
Lost to a baseline
Fiber optic SPR biosensor with a solid-phase enzymatic reaction device (Zhang et al. 2022) achieved a higher sensitivity (3.10 a.u./mg.dl⁻¹) than this work's in-vivo glucose sensor (0.0354 a.u./mg.dl⁻¹).
Opto-chemical biosensor development, and analytics for point-of-care applications · Iowa State · PhD
Lost to a baseline
Cu3(HHTP)2 and Ni3(HHTP)2 based aptasensors showed higher charge-transfer resistance changes and lower sensitivity toward C6 glioma cells and EGFR compared to bimetallic CuxNi3-x(HHTP)2
New Metal Complexes and Metal-Organic Frameworks (MOFs) with Potential Biological Applications · University of Camerino · PhD
Lost to a baseline
Hollow fiber electrochemical sensor showed sensitivity per surface area of 0.69 x 10^-6 A/mM/mm^2 compared to 8 x 10^-6 A/mM/mm^2 for the fiber tip sensor due to lower exposed carbon black
Ultimate Feature Sizes in Thermally Drawn Fibers: from Fundamental Analysis to Novel Functional Fibers · EPFL · PhD
Left open by the authors
Problems the authors named and did not get to.
Left open
Test hybridization and restriction enzyme assay performance of the electrochemical biosensor in real biological matrices such as whole blood. Blocker: Requires a wet lab, blood samples, biological reagents, and electrochemical instrumentation
Engineering DNA-based electrochemical diagnostics for translational applications · MIT · PhD
Left open
Characterise and adapt the modified screen-printed carbon electrode electrochemical sensor mechanism for whole blood and plasma samples. Blocker: Requires a wet lab, blood/plasma samples, and electrochemical sensing apparatus (electrodes, potentiostat, reagents)
Development of an electrochemical sensor for measuring haemolysis products in urine · Imperial · PhD
Left open
Perform controlled experiments to map blood coagulation stages to resonant peak shifts using the optofluidic sensor. Blocker: Requires a physical optofluidic sensor, wet lab environment, and fresh blood samples
Integrated bio-photonic devices : sensors, imagers, and beyond · MIT · PhD
Left open
Implement AC or three-electrode electrochemical sensing with interdigitated electrodes and Wheatstone bridge amplification for microfluidic bacterial detection. Blocker: Requires microfabrication facilities, wet lab apparatus, and biological samples to build and test sensor hardware.
Microfluidics Sensor to Detect Water Salinity and Bacteria Using Optical and Electrical Methods · York University · Master's
Left open
Optimize experimental blocking parameters using charged proteins to minimize non-selective signals while maintaining sandwich assay sensitivity in impedimetric biosensors. Blocker: Requires a wet chemistry and electrochemistry lab to prepare gold electrodes, perform functionalization, and run EIS measurements
Methods to Improve the Stability and Selectivity of Electronic Biosensors · Georgia Tech · PhD
Left open
Develop and evaluate aptamer-based bioreceptors using SELEX as alternatives to antibodies in electronic biosensors. Blocker: Requires wet-lab biochemistry facilities to perform SELEX and characterize electrochemical biosensors
Methods to Improve the Stability and Selectivity of Electronic Biosensors · Georgia Tech · PhD
Left open
Optimize the OM-SLB platform sensor surface concentration and device sensitivity using organic electrochemical transistors. Blocker: Requires a wet lab and physical fabrication/testing of organic electrochemical transistors and lipid bilayers
THE DEVELOPMENT OF COMPLEX BIOMEMBRANE PLATFORMS TO INVESTIGATE THE IMPACT OF MEMBRANE DISRUPTING AGENTS ON MEMBRANE BIOPHYSICAL PROPERTIES · Cornell · PhD
Left open
Miniaturize the electrochemical sensing platform and adapt it for multiplexed nucleic acid biomarker detection. Blocker: Requires a physical wet lab, electrochemical hardware, and biochemical reagents
Development of electrochemical sensors for nucleic acid biomarkers · Imperial · PhD
Who has worked on this
Authors of the public theses cited on this page, most-cited first.
- Xingcheng Zhou · MIT · PhD · 2025
Engineering DNA-based electrochemical diagnostics for translational applications - Hilena Gezahagne · Georgia Tech · PhD · 2024
Methods to Improve the Stability and Selectivity of Electronic Biosensors - Xiaotong Meng · Imperial · PhD · 2023
Development of electrochemical sensors for nucleic acid biomarkers - Owen Griffiths · Imperial · PhD · 2023
Development of an electrochemical sensor for measuring haemolysis products in urine - Georgia Smith · Imperial · PhD · 2023
Development of a microfluidic biosensing system for real-time monitoring of acetylcholinesterase activity - Souvik Kundu · Iowa State · PhD · 2023
Opto-chemical biosensor development, and analytics for point-of-care applications - Lauren Batey · Imperial · PhD · 2025
Optimization of in vivo electrochemical detection of neurotransmitters and application to neurological pathologies - Josiah Rudge · Georgia Tech · PhD · 2025
Single-Cell Impedance Cytometry for the Control of Single-Cell Electroporation in a Flow-Through Device - Joshua M. Rinehart · Georgia Tech · PhD · 2025
To Cleave or Not To Cleave: Side-Chain Design in Dioxythiophene Polymers - Vishal Venkatesh · Penn · PhD · 2025
MICROFABRICATED DEVICES FOR IN-VIVO SENSING FOR MITOCHONDRIAL ASSESSMENT - Yann Christophe Sprunger · EPFL · PhD · 2025
Biomarkers in Interstitial Fluid: From Screening to Sensor Development - Shulin Zhang · Imperial · PhD · 2024
Biosensors for exhaled breath condensate analysis
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