Signal Transduction Mechanism of Graphene Biosensors: From Molecular Recognition to Electrical/Optical Signal Readout and Materials Selection
Signal Transduction Mechanism of Graphene Biosensors: From Molecular Recognition to Electrical/Optical Signal Readout and Materials Selection
1. The Key Challenge in Bioanalysis: How Molecular Recognition Signals Can Be Read Out Reliably
1.1 Recognition of a Target Molecule Does Not Automatically Produce a Detection Result
In bioanalysis, confirming the presence of a target molecule is only one part of the detection process. The more critical question is: when an antigen binds to an antibody, deoxyribonucleic acid (DNA) undergoes hybridization, an enzymatic reaction produces a detectable product, or a protein biomarker is captured, how can these molecular recognition processes be converted into signals that can be read by an instrument?
The core function of a biosensor is to convert the subtle changes caused by target-molecule binding or reaction events into stable, quantifiable electrical or optical signals. A typical biosensor usually consists of three components:
Component | Main Function | Common Forms |
Biorecognition layer | Selectively binds the target molecule | Antibodies, enzymes, DNA probes, aptamers |
Signal transduction layer | Converts recognition events into measurable signals | Graphene, gold electrodes, carbon materials, semiconductor materials |
Signal readout layer | Outputs the detection result | Current, voltage, resistance, conductance, fluorescence signal |
The value of graphene in biosensors is mainly reflected in the signal transduction step. It does not replace antibodies, enzymes, or nucleic acid probes in performing specific recognition. Instead, it helps convert the changes caused by target-molecule binding or reactions more effectively into changes in current, conductance, impedance, or fluorescence signals.
1.2 Graphene Improves the Signal Transduction Efficiency Between the Recognition Layer and the Readout Layer
In many bioanalytical systems, the challenge is not only to recognize or capture the target molecule, but also to reliably read out the weak signal generated after the target molecule is captured. Common challenges include:
① Low target-molecule concentration, resulting in weak signal changes caused by target binding or reactions;
② Insufficient electron transfer efficiency between biomolecules and electrodes;
③ A limited number of recognition molecules that can be immobilized on the surface of an electrode or device;
④ The presence of multiple interfering substances in real samples such as blood, saliva, sweat, and urine;
⑤ The need for detection devices to be miniaturized, fast in response, and suitable for continuous monitoring or on-site testing.
Graphene has attracted attention because it can serve as a transduction material between the biorecognition layer and the signal readout layer, helping convert changes caused by target binding, recognition, or reactions into detectable signals more efficiently.
2. Why Graphene Can Improve Signal Transduction
Graphene is a two-dimensional carbon material with a relatively high specific surface area. For biosensors, this means that the material surface can provide more contact sites for immobilizing enzymes, antibodies, DNA probes, or aptamers. When the target-molecule concentration is low, the sensor needs to maximize the opportunity for target molecules to interact with recognition molecules. A higher effective surface area helps increase the loading capacity of recognition molecules, thereby improving the detection response.
However, a high specific surface area does not directly mean high selectivity. Whether a sensor can accurately recognize glucose, dopamine, uric acid, proteins, or nucleic acids mainly depends on the recognition elements immobilized on the surface. The role of graphene is to improve signal transmission and readout efficiency after the recognition event occurs.
2.2 Good Electron Transfer Capability Helps Enhance Electrochemical Response
In electrochemical biosensors, detection signals usually originate from redox reactions, enzymatic reaction products, or changes in surface charge at the electrode. In this context, whether the electrons generated by the reaction can be rapidly transferred to the electrode directly affects the response speed and signal intensity.
Reduced graphene oxide (rGO) usually has better electrical conductivity than graphene oxide (GO) and is commonly used for electrochemical electrode modification. rGO can increase the effective reaction area of the electrode and improve the electron transfer process, making current changes caused by target molecules or reaction products easier to detect.
However, the performance of rGO is not fixed. Its conductivity, surface defects, residual functional groups, and dispersion state are affected by the degree of reduction, preparation method, and post-treatment process. For practical detection, material consistency is just as important as electrochemical response intensity.
2.3 Atomic-Scale Thickness Makes Graphene Sensitive to Surface Charge Changes
The detection logic of graphene field-effect transistor (GFET) sensors is different from that of traditional electrochemical sensors. In a GFET, graphene usually serves as the conductive channel. When a target molecule binds to the graphene surface or changes the local charge environment near graphene, the carrier concentration in the graphene channel may change, thereby causing changes in conductance or current.
The value of this detection mode lies in the fact that the target molecule does not necessarily need to produce color, fluorescence, or redox products. Under appropriate ionic strength, surface modification, and device structure, local charge changes caused by target binding may be read out by the GFET. This is also an important reason why GFETs are used for label-free detection. Label-free detection refers to detection that does not rely on fluorescent dyes, enzyme labels, or radioactive labels, but instead directly generates a detection signal through the interaction between the target molecule and the sensing surface.
2.4 Surface Modifiability Determines Whether Graphene Can Connect with Biorecognition Molecules
For graphene materials to be used in bioanalysis, conductivity and high specific surface area alone are not sufficient. Recognition molecules must be stably immobilized on the material surface while maintaining their activity during detection. GO contains oxygen-containing functional groups such as hydroxyl, carboxyl, and epoxy groups on its surface, making it relatively easy to link or adsorb proteins, DNA, aptamers, polymers, and other molecules. Therefore, GO is commonly used for biomolecule immobilization and optical detection.
While rGO partially restores conductivity, it also retains some defects and functional groups, making it more suitable for electrochemical electrode modification. Chemical vapor deposition (CVD) graphene is more suitable for preparing continuous thin films and is used in transistor devices, flexible electronic devices, and bioelectronic interfaces.
3. Functional Differences Among GO, rGO, and CVD Graphene
3.1 GO: Suitable for Constructing Modifiable Biorecognition Interfaces
The advantages of GO lie in its abundant oxygen-containing functional groups, good dispersibility, and ease of chemical modification. GO is commonly used in the following detection designs:
① DNA probe immobilization;
② Aptamer-based detection;
③ Protein adsorption or coupling;
④ Fluorescence quenching/fluorescence resonance energy transfer (FRET) detection;
⑤ Optical signal modulation.
In optical biosensors, GO is often used to adsorb fluorescently labeled single-stranded DNA or aptamers and to construct “on/off” detection systems based on its fluorescence quenching ability. When the target molecule is present, the conformation or adsorption state of the probe changes, causing the fluorescence signal to change accordingly and enabling target recognition.
3.2 rGO: Suitable for Enhancing Electrochemical Signals
After reduction treatment, rGO usually has higher conductivity than GO. Although defects may still exist in its structure, these defects and residual functional groups can also provide sites for electrode modification. In electrochemical biosensors, the main roles of rGO include:
Role | Effect on Detection |
Increasing the effective electrode area | Increases the loading capacity of recognition molecules and the number of reaction sites |
Improving electron transfer | Enhances current response and shortens response time |
Providing sites for composite modification | Facilitates combination with enzymes, metal nanoparticles, and polymers |
Improving interfacial charge transfer in certain systems | Helps improve detection sensitivity |
rGO is commonly used in electrochemical detection studies involving glucose, dopamine, uric acid, ascorbic acid, DNA, and other targets. The detection performance of rGO is closely related to the material preparation process. The degree of oxidation, degree of reduction, lateral size, number of layers, defect density, and dispersion state all affect the response intensity and reproducibility of the sensor.
3.3 CVD Graphene: Suitable for Device-Based Electrical Detection
The CVD method can be used to prepare continuous graphene films, making it more suitable for GFETs, flexible electronic devices, and bioelectronic interfaces. Compared with GO and rGO, the main characteristics of CVD graphene are:
① Good film continuity;
② Better compatibility with micro- and nano-device fabrication;
③ Single-layer or few-layer structures that are sensitive to surface charge changes;
④ Compatibility with flexible substrates for patch-type or miniaturized detection devices.
In GFETs, CVD graphene can serve as the conductive channel. After target binding, if the charge distribution near graphene is altered, the channel conductance may be affected, forming a readable signal. However, CVD graphene devices also face fabrication challenges. Film growth quality, grain boundaries, transfer residues, cracks, substrate contamination, and surface functionalization methods can all affect the final detection performance.
4. Two Main Types of Sensors: Electrochemical Sensors and GFET Sensors
4.1 rGO Electrochemical Biosensors: Suitable for Rapid, Low-Cost Detection
The basic logic of rGO electrochemical biosensors is that the target molecule or its reaction product generates electrochemical changes on the electrode surface. rGO increases the reaction interface and improves electron transfer, making changes in current or impedance easier to detect. This detection mode is suitable for analytes that can undergo electrochemical reactions or whose signals can be read out electrically through enzymatic reactions or redox probes.
Detection Target | Common Detection Method | Main Role of rGO |
Glucose | Enzymatic reaction produces an electrochemical signal | Improves electron transfer and increases response intensity |
Dopamine | Redox reaction | Enhances current response |
Uric acid | Electrochemical oxidation reaction | Improves electrode interface response |
DNA | Hybridization recognition or electrochemical-label readout | Provides an interface for probe immobilization and charge transfer |
Proteins | Antibody or aptamer recognition | Enhances surface reactions and signal readout |
The advantages of this type of sensor include fast detection, relatively simple equipment, and low cost, making it suitable for development toward portable detection devices. However, its scope of application depends on whether the target molecule can generate a measurable electrochemical signal. If the target molecule itself does not readily undergo electrochemical reactions, enzymes, nanomaterials, redox probes, or other signal-amplification designs usually need to be introduced. This increases system complexity and also makes stability and reproducibility more difficult to control.
4.2 GFET Biosensors: Suitable for Label-Free, Real-Time Electrical Detection
The basic logic of GFET biosensors is that after the target molecule binds to the graphene surface, it changes the local charge environment, thereby modulating the conductance of the graphene channel and forming a readable electrical signal. Compared with electrochemical sensors, GFETs do not necessarily rely on redox reactions of the target molecule, nor do they necessarily require fluorescent labeling. They are more suitable for label-free detection based on surface charge changes. The main value of GFETs lies in the following aspects:
Detection Requirement | Advantage of GFET |
Rapid detection | Target binding can directly induce an electrical response |
Label-free detection | Reduces the need for dyes, enzyme labels, or secondary antibody steps |
Miniaturized devices | The transistor structure is suitable for integrated fabrication |
Flexible detection | CVD graphene can be combined with flexible substrates |
Continuous readout | Conductance changes can be monitored in real time |
The sensitivity of GFETs comes from the two-dimensional structure of graphene. Single-layer or few-layer graphene has a highly exposed surface, and surface adsorption or charge perturbation can directly affect its electrical properties.
The practical detection performance of GFETs is limited by multiple factors. Non-specific adsorption in complex samples, changes in ionic strength, pH fluctuations, Debye screening effects, device noise, and signal drift can all affect result interpretation. Therefore, the key issue for GFETs is not whether a response can be generated, but whether the response mainly originates from target-molecule binding rather than background interference or device drift.
5. What Still Needs to Be Solved When Moving from Laboratory Results to Practical Detection
5.1 Selectivity Still Depends on Biorecognition Molecules
Graphene is sensitive to surface changes, which helps improve detection response. However, this also means that it may respond to non-target molecule adsorption, changes in ion concentration, or pH fluctuations.
Therefore, graphene sensors need reliable recognition elements to ensure selectivity, including enzymes, antibodies, aptamers, DNA probes, molecularly imprinted polymers, and specific receptor proteins. If the recognition layer has insufficient selectivity, the high sensitivity of graphene may lead to higher background noise rather than more accurate detection results.
5.2 Real Samples Significantly Increase Detection Difficulty
Buffer systems have simple compositions and controllable target concentrations, making it easier to obtain ideal detection results. However, real samples contain large numbers of interfering components, and sensors must operate in much more complex chemical and biological environments.
Sample Type | Main Challenge |
Blood | High protein content; prone to non-specific adsorption |
Saliva | Composition varies significantly; target concentration may be low |
Sweat | Ionic strength, pH, and secretion rate vary markedly |
Urine | Complex metabolites and large individual differences |
Interstitial fluid | Sampling methods and long-term stability requirements are demanding |
If a graphene sensor performs well only in buffer solution, this is not sufficient to demonstrate that it is suitable for practical detection. Selectivity, interference resistance, reproducibility, and stability in real samples are important criteria for evaluating its application value.
5.3 Material and Device Consistency Determines Whether Results Are Reliable
The performance of GO, rGO, and CVD graphene is affected by preparation processes. For GO and rGO, the degree of oxidation, degree of reduction, lateral size distribution, number of layers, defect density, and dispersion state all affect electrode surface reactions and signal output. For CVD graphene, growth quality, transfer process, cracks, residues, and substrate contamination can also affect GFET device performance.
For research validation, good results may be obtained with a single batch of material. For practical detection, however, it is more important that different batches of materials and devices maintain consistent responses. The reliability of graphene sensors depends not only on material properties, but also on preparation processes, surface functionalization methods, and quality control capability.
6. How to Evaluate Whether a Graphene Sensor Design Is Reliable
When evaluating graphene biosensors, six key questions should be considered.
Evaluation Question | What to Focus On |
1. What is the detection target? | Small molecules, proteins, nucleic acids, ions, or cellular signals correspond to different mechanisms |
2. What is the recognition element? | Enzymes, antibodies, aptamers, DNA probes, or other recognition materials |
3. How is the signal generated? | Current, conductance, impedance, fluorescence, or other measurable changes |
4. What role does graphene play? | Immobilizing recognition molecules, enhancing electrode response, or serving as a transistor channel |
5. Which type of graphene material is used? | GO, rGO, and CVD graphene correspond to different functions |
6. Are the validation conditions close to practical applications? | Whether real samples are used, and whether interference resistance, reproducibility, and stability are evaluated |
Graphene sensors with application potential are usually designed around specific detection targets, real-sample environments, recognition-element stability, and readout mechanisms. Only in this way can the material advantages of graphene be truly translated into reliable detection capability.
7. Classification Tables of Representative Chemicals Related to Graphene Biosensors
Table 1. Core Graphene Materials and Carbon-Based Conductive Materials
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Graphene field-effect transistor device | — | G475809 | Graphene field-effect transistor chip | S10 | Used for label-free electrical detection, surface charge response testing, and graphene field-effect sensor research |
CVD graphene film | — | M485946 | Monolayer graphene film | 1 cm × 1 cm on SiO₂/Si substrate | Used for device-based electrical detection, surface functionalization, and graphene-channel sensing research |
CVD graphene film | — | M466390 | Monolayer graphene film | 1 inch × 1 inch copper foil with PMMA coating | Used for graphene transfer, device fabrication, and thin-film electrical property studies |
Graphene oxide material | — | G475662 | Graphene oxide | pH-stable dispersion in 0.05 M HEPES buffer, pH 7.5 | Used for recognition molecule immobilization, surface adsorption, and optical detection research under biological buffer conditions |
Graphene oxide material | — | G466391 | Graphene oxide | 2 mg/mL, dispersed in H₂O | Used for electrode coating, nucleic acid probe adsorption, aptamer immobilization, and construction of biointerfaces |
Functionalized graphene oxide | — | G466384 | Graphene oxide, amine-functionalized | 1 mg/mL, dispersed in H₂O | Used for biomolecule coupling, amino-interface modification, and construction of recognition layers |
Functionalized graphene | 7782-42-5 | G293467 | Aminated graphene, nanosmall size | Diameter: 100–200 nm; single-layer ratio: >99%; amine ratio: 4.0 wt% | Used for coupling antibodies, enzymes, and nucleic acid probes, and for constructing high-specific-surface-area recognition interfaces |
Functionalized graphene | 7782-42-5 | G196556 | Carboxylated graphene, nanosmall size | Diameter: 50–200 nm; single-layer ratio: >98%; carboxyl ratio: 8.0 wt% | Used for carbodiimide coupling, protein immobilization, nucleic acid probe conjugation, and electrode interface modification |
Functionalized graphene | 7782-42-5 | G196553 | Hydroxylated graphene, nanosmall size | Diameter: 50–150 nm; single-layer ratio: >98%; hydroxyl ratio: 12 wt% | Used for hydrophilicity regulation, composite-film construction, and sensing-interface modification |
Functionalized graphene | 7782-42-5 | G196555 | Thiolated graphene | Single-layer ratio: >80%; thiol ratio: 4.0 wt% | Used for binding to metal surfaces, gold electrode modification, and construction of nanogold composite sensing interfaces |
Reduced graphene oxide material | — | R487602 | Reduced graphene oxide | Chemically reduced, single-layer, lateral size 1–5 μm | Used for electrochemical electrode modification, electron-transfer enhancement, and current-response studies |
Reduced graphene oxide material | — | R485644 | Reduced graphene oxide | 10 mg/mL, dispersed in H₂O | Used for electrode drop-casting, composite material preparation, and electrochemical biosensor modification |
High-purity graphene material | 7782-42-5 | S491698 | High-purity graphene | Single-layer ratio >99.8%; thickness 0.8–1.2 nm; diameter 0.8–3 μm | Used for fundamental graphene material research, conductive-interface construction, and control experiments for sensing materials |
Graphene quantum dot material | — | G196611 | Graphene quantum dots | 1 mg/mL; lateral size 3–6 nm | Used for fluorescence detection, optical signal readout, and construction of nanoprobe systems |
Carbon-based conductive enhancement material | 308068-56-6 | Single-walled carbon nanotubes | ≥95% (≥99% as carbon nanotubes), average diameter 0.84 nm | Used for conductive-network enhancement, composite electrode construction, and electrochemical response improvement | |
Carbon-based conductive enhancement material | 308068-56-6 | Multi-walled carbon nanotubes | ≥90% carbon basis, D × L 110–170 nm × 5–9 μm | Used for composite electrodes, conductive frameworks, and mechanical stability studies of sensing materials |
Table 2. Surface Coupling and Interfacial Functionalization Reagents
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Crosslinking immobilization reagent | 111-30-8 | Glutaraldehyde (50%) | Photographic grade, 50% in H₂O | Used for crosslinking immobilization between aminated surfaces and enzymes, antibodies, or proteins | |
Non-covalent graphene modification reagent | 129-00-0 | Pyrene | Sublimed grade, ≥99% | Used for studies of π–π interactions on graphene surfaces and adsorption modification with aromatic molecules | |
Metal nanomaterial precursor | 16961-25-4 | Chloroauric acid trihydrate | ≥99.9% metals basis | Used for preparation of gold nanoparticles, gold-modified electrodes, and thiol-interface construction | |
Silanization reagent | 919-30-2 | 3-Aminopropyltriethoxysilane (APTES) | ≥99% | Used for amino-functionalization of glass, silica, and oxide surfaces, and for immobilization of recognition molecules | |
Carboxyl activation reagent | 25952-53-8 | 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride | ≥98% | Used for amide-bond coupling between carboxyl and amino groups, supporting immobilization of proteins, enzymes, and nucleic acid probes | |
Non-covalent graphene linker | 3443-45-6 | 1-Pyrenebutyric acid | ≥98% | Used for π–π adsorption on graphene surfaces and subsequent carboxyl-based coupling modification | |
Active ester coupling reagent | 6066-82-6 | N-Hydroxysuccinimide (NHS) | ≥98% | Used together with carbodiimide for carboxyl activation, improving coupling efficiency of proteins and probes | |
Aqueous active ester coupling reagent | 106627-54-7 | N-Hydroxysulfosuccinimide sodium salt (Sulfo-NHS) | ≥98% | Used for aqueous carboxyl activation and biomolecule coupling in hydrophilic systems | |
Epoxy silane modification reagent | 2530-83-8 | 3-Glycidyloxypropyltrimethoxysilane | ≥97% | Used to introduce epoxy groups, supporting immobilization of amino-containing proteins, enzymes, and probes | |
Thiol silane modification reagent | 4420-74-0 | (3-Mercaptopropyl)trimethoxysilane | ≥95% | Used to introduce thiol interfaces, supporting binding to metal surfaces and gold electrode modification | |
Non-covalent graphene linker | 114932-60-4 | 1-Pyrenebutyric acid N-hydroxysuccinimide ester | ≥95% | Used for non-covalent adsorption on graphene surfaces and coupling of proteins, antibodies, and aptamers |
Table 3. Materials for Polymer Immobilization, Dispersion Stabilization, and Anti-Non-Specific Adsorption
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Bio-polymer immobilization material | 9012-76-4 | Chitosan | Medium viscosity, 200–400 mPa·s | Used for enzyme immobilization, film formation, electrode surface modification, and construction of biocompatible interfaces | |
Surfactant | 9005-64-5 | Tween 20 (TWEEN® 20) | Viscous liquid | Used for washing, reducing non-specific adsorption, and background control in immunosensing experiments | |
Film-forming polymer | 9002-89-5 | Mowiol® PVA-124 polyvinyl alcohol (PVA) | Viscosity: 54–66 mPa·s | Used for flexible films, immobilization layers, composite coatings, and electrode protective layers | |
Hydrophilic polymer | 25322-68-3 | Polyethylene oxide | Viscosity 65–115 cps | Used for hydrophilic interface regulation, dispersion stabilization, and anti-adsorption studies of biointerfaces | |
Amphiphilic polymer | 9003-11-6 | K434429 | Kolliphor® P 407 | Oxyethylene content 71.5–74.9% | Used for nanomaterial dispersion, surface stabilization, and interface regulation in bioanalytical systems |
Blocking protein | 9048-46-8 | Bovine serum albumin (BSA) | Sterile-filtered, for cell culture, low endotoxin, 10% in DPBS, fatty acid free | Used for sensor surface blocking, reducing non-specific adsorption, and controlling background in immunoassays | |
Dispersion-stabilizing polymer | 9003-39-8 | P657448 | Polyvinylpyrrolidone (PVP) | Animal-free, low endotoxin, for cell culture, K30 | Used for nanomaterial dispersion, particle stabilization, and preparation of composite sensing materials |
Nonionic surfactant | 9002-93-1 | Triton™ X-100 | Biochemical reagent, peroxide value ≤7 meq/kg | Used for surface cleaning, membrane treatment, sample processing, and regulation of non-specific adsorption | |
Cationic polymer | 9002-98-6 | Branched polyethyleneimine (PEI) | Average Mw ~25,000 by LS; average Mn ~10,000 by GPC; branched | Used to introduce amino groups, immobilize nucleic acids, regulate surface charge, and enhance material dispersion | |
Anionic polyelectrolyte | 25704-18-1 | Poly(sodium 4-styrenesulfonate) (PSS) | Average Mw ~1,000,000, powder | Used for layer-by-layer assembly, surface charge regulation, and construction of conductive composite interfaces | |
Electrode membrane material | 31175-20-9 | Nafion™ perfluorinated membrane | Thickness 0.002 inch | Used for electrode protective membranes, ion-conducting layers, and anti-interference interfaces in electrochemical sensing | |
Blocking protein | 9000-71-9 | Casein | Industrial grade | Used for blocking in immunoassays, reducing non-specific binding, and controlling background signals | |
Cationic polyelectrolyte | 26062-79-3 | Poly(diallyldimethylammonium chloride) (PDADMAC) | Mw 200,000–350,000; 20 wt% in water; 250–500 cP at 25 °C | Used for charged-layer assembly, construction of graphene composite films, and surface charge regulation |
Table 4. Biorecognition Reagents, Enzymes, and Model Analytes
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Enzyme-labeled recognition reagent | 9003-99-0 | Biotinylated horseradish peroxidase | Carrier-free, azide-free, EnzymoPure™, 1.0 mg/mL | Used for enzyme-label signal amplification, biotin-affinity systems, and immunosensing detection | |
Model analyte | 50-99-7 | D432810 | D-(+)-Glucose | Anhydrous grade, PharmPure™, USP, BP, European Pharmacopoeia (Ph.Eur.), ACS | Used for glucose sensor performance evaluation, enzymatic reaction models, and electrochemical detection |
Model analyte | 57-88-5 | C657147 | Cholesterol | Animal-free, low endotoxin, for cell culture, ≥99% | Used for cholesterol oxidase sensing systems and metabolic biomarker detection studies |
Enzymatic reaction product/oxidation substrate | 7722-84-1 | Hydrogen peroxide solution | Suitable for microbiology, 3% | Used for oxidase sensor response testing and electrochemical detection of peroxides | |
Biorecognition enzyme | 9028-76-6 | Recombinant cholesterol oxidase (CHO) | Bioactive, recombinant, ActiBioPure™, high performance, EnzymoPure™, ≥90% by SDS-PAGE, ≥8 U/mg enzyme powder | Used for cholesterol detection, oxidase-based electrochemical biosensors, and metabolite analysis | |
Biorecognition enzyme | 9001-37-0 | Recombinant glucose oxidase (GOD) | Bioactive, recombinant, ActiBioPure™, high performance, EnzymoPure™, ≥90% by SDS-PAGE, ≥150 U/mg enzyme powder; ≥300 U/mg protein | Used for glucose electrochemical biosensors and oxidase immobilization studies | |
Biorecognition enzyme | 9002-12-4 | Urate oxidase (UAO) | Bioactive, recombinant, ActiBioPure™, high performance, EnzymoPure™, ≥80% by SDS-PAGE, expressed in E. coli, 8–12 U/mg enzyme powder | Used for uric acid detection, electrochemical enzyme sensors, and metabolite analysis | |
Biorecognition enzyme | 9028-72-2 | Recombinant lactate oxidase (LOX) | Bioactive, recombinant, ActiBioPure™, high performance, EnzymoPure™, ≥100 U/mg enzyme powder; ≥250 U/mg protein | Used for lactate detection, sweat sensing, and oxidase-based electrochemical detection systems | |
Model analyte/interferent | 103-90-2 | Acetaminophen | Chemically pure (CP), ≥98% by HPLC | Used for small-molecule electrochemical detection, pharmaceutical analysis, and evaluation of interferent response | |
Model analyte/interferent | 50-81-7 | L-Ascorbic acid | UltraBio™, ultrapure grade, ≥99.5% (RT) | Used for interference experiments in electrochemical sensors, antioxidant small-molecule detection, and selectivity evaluation | |
Model analyte | 79-33-4 | S485917 | (S)-Lactic acid | PharmPure™, BP, European Pharmacopoeia (Ph.Eur.) | Used for lactate sensors, sweat metabolite detection, and oxidase reaction systems |
Affinity immobilization reagent | 58-85-5 | Biotin | PharmPure™, USP | Used for biotin–streptavidin immobilization systems and probe labeling | |
Model analyte | 62-31-7 | Dopamine hydrochloride | Moligand™, ≥98% | Used for dopamine electrochemical detection, neurotransmitter model analysis, and selectivity evaluation | |
Model analyte | 69-93-2 | Uric acid certified reference material | Moligand™, ≥99.8% | Used for uric acid sensor calibration, standard curve establishment, and metabolite detection | |
Model analyte | 51-61-6 | Dopamine | Moligand™, ≥98% | Used for neurotransmitter electrochemical detection and studies of graphene electrode response | |
Affinity immobilization reagent | 9013-20-1 | Streptavidin | From Streptomyces avidinii, ≥12 U/mg protein | Used for immobilization of biotinylated antibodies, enzymes, and nucleic acid probes, and for construction of recognition layers |
Table 5. Electrochemical Probes, Mediators, and Electrode Auxiliary Materials
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Reference electrode-related material | 7783-90-6 | Silver chloride | Suitable for analysis, guaranteed reagent, ≥99% | Used for preparation of silver/silver chloride reference electrodes and electrochemical testing systems | |
Electrochemical mediator | 14038-43-8 | Prussian blue | Biological stain | Used for hydrogen peroxide detection, electrode modification, and signal transduction in enzyme sensors | |
Redox probe | 14459-95-1 | Potassium hexacyanoferrate(II) trihydrate | European Pharmacopoeia (Ph.Eur.), suitable for analysis, ACS, guaranteed reagent | Used for cyclic voltammetry, electrochemical impedance spectroscopy, and evaluation of electron transfer at electrode interfaces | |
Redox probe | 13746-66-2 | Potassium hexacyanoferrate(III) | European Pharmacopoeia (Ph.Eur.), suitable for analysis, ACS, guaranteed reagent | Used for electrode performance testing, charge-transfer resistance analysis, and evaluation of interfacial modification | |
Metal electrode material precursor | 7761-88-8 | S433976 | Silver nitrate (explosive precursor) | European Pharmacopoeia (Ph.Eur.), suitable for analysis, ACS, guaranteed reagent | Used for silver nanomaterial preparation, silver-based electrode modification, and research on electrochemical detection materials |
Transparent conductive material | 50926-11-9 | Indium tin oxide | Nanopowder, particle size <50 nm | Used for transparent conductive electrodes, photoelectrochemical detection, and graphene composite electrodes | |
Electrochemical dye/mediator | 61-73-4 | Methylene blue | 1% | Used for nucleic acid electrochemical detection, redox signal labeling, and electrode response studies | |
Redox mediator | 102-54-5 | Ferrocene | ≥99% | Used for electrochemical labeling, electron-transfer mediation, and sensor signal construction | |
Electrochemical dye/mediator | 92-31-9 | Toluidine Blue O | — | Used for electrochemical signal labeling, nucleic acid detection, and redox response studies |
Table 6. Buffer Salts, Supporting Electrolytes, and Sample Processing Reagents
Category | CAS No. | Aladdin Cat. No. | Name | Specification or Purity | Product Features and Applications |
Phosphate buffer component | 7778-77-0 | P434012 | Potassium dihydrogen phosphate | For analysis, ≤0.005% Na, guaranteed reagent, ACS, ISO, Reag. Ph.Eur. | Used for phosphate buffer preparation, ionic strength control, and electrochemical detection systems |
Phosphate buffer component | 7558-79-4 | D774741 | Disodium hydrogen phosphate | Anhydrous grade, PharmPure™, USP, JP, BP, European Pharmacopoeia (Ph.Eur.) | Used for phosphate buffer preparation, biomolecule stabilization, and sensor testing systems |
Supporting electrolyte | 7647-14-5 | Sodium chloride | Anhydrous grade, high-purity, reagent grade, ≥99% | Used for ionic strength adjustment, buffer preparation, and simulation of physiological saline environments | |
Supporting electrolyte | 7447-40-7 | Potassium chloride | Anhydrous grade, ACS, ≥99% | Used as an electrochemical supporting electrolyte, in reference electrode systems, and for ionic environment adjustment | |
Biological buffer | 7365-45-9 | N-2-Hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES) | Animal-free, for cell culture, ≥99.5%, ultra-low endotoxin | Used for biological detection buffer systems, cell-related sensing experiments, and pH-stable environments | |
Metal ion chelator | 6381-92-6 | Ethylenediaminetetraacetic acid disodium salt dihydrate | HPLC grade, ≥99% | Used for metal ion chelation, sample processing, and background interference control | |
Biological buffer | 77-86-1 | Tris(hydroxymethyl)aminomethane (Tris base) | Molecular biology grade, ≥99.9% (T) | Used in buffer systems for nucleic acid, protein, and enzyme sensing experiments | |
Carboxyl coupling buffer | 4432-31-9 | 2-(N-Morpholino)ethanesulfonic acid (MES) | Molecular biology grade, ≥99.5% (T) | Used as a buffer for carbodiimide coupling reactions and carboxyl activation experiments |
Note: The products listed above are representative Aladdin products related to scientific research and formulation studies. For more product specifications, grades, and COA information, please search by “product name/CAS/catalog number” on the Aladdin official website.
References
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