What Is a Biosensor?
A biosensor is an analytical device that combines a biological recognition element (e.g., enzymes, DNA, or cells) with a transducer to detect specific substances. It converts a biological event – such as the binding of a toxin or metal ion – into a measurable signal (electrochemical, optical, or piezoelectric).
Biosensors are indispensable in areas such as:
- Environmental monitoring (e.g., heavy metals, pesticides)
- Medical diagnostics (e.g., glucose, cancer markers)
- Food safety control (e.g., pathogens, freshness indicators)
Why Chitosan?
Chitosan is a natural biopolymer derived from the deacetylation of chitin (from crustacean shells or fungi). It is non-toxic, biodegradable, and possesses a key chemical feature:
Amino groups that interact strongly with ions, molecules, or biomolecules.
These properties make chitosan an ideal material for biosensor development.
Functions of Chitosan in Biosensors
Chitosan typically serves the following functions in biosensors:
1. Matrix for Biomolecules
- Immobilizes enzymes, DNA, or antibodies via covalent or electrostatic interactions
- Protects biomolecular structure and preserves activity
2. Ion Exchange & Recognition
- Amino groups interact with heavy metals (e.g., Pb²⁺, Cd²⁺) or organic compounds (e.g., pharmaceuticals)
- Enables high selectivity and reusability
3. Signal Enhancement
- Chitosan films can be modified for conductivity (e.g., via embedded nanoparticles)
- Enhances electrochemical performance (e.g., redox current, detection limits)
Innovations in Research
Recent developments combine chitosan with other functional materials:
| Combination | Advantage |
| Chitosan + Graphene | High conductivity, large surface area |
| Chitosan + Gold | nanoparticles Enzyme activity, biocompatibility |
| Chitosan + Lignocellulose | Structure and function for sustainable sensing |
Printed and flexible sensors on paper or textile substrates also benefit from chitosan's film-forming properties.
Applications
| Field | Detection of |
| Environmental analysis | Heavy metals, nitrates, pesticides |
| Medical diagnostics | Uric acid, glucose, tumor markers |
| Food quality control | Bacteria, antibiotic residues |
| Water analysis | Pb²⁺, Hg²⁺, organophosphates |
Example:
An electrochemical sensor with a chitosan-gold film detects lead ions in drinking water with a detection limit of < 0.1 µM – reliably and regenerably.
Chitosan Quality for Research and Application
The effectiveness of a sensor depends strongly on the quality of the chitosan used:
- Degree of deacetylation (> 75% for high reactivity)
- Molecular weight (low to high, depending on the application)
- Purity (e.g., GMP-grade for medical use)
In our online shop, you’ll find a wide selection of high-purity chitosans suitable for applications in sensor technology and life sciences. Feel free to contact us – we’ll be happy to advise you and help you find the right product for your project!
Conclusion
Chitosan is more than just a carrier material – it is an active component of modern biosensors. Its natural origin, chemical versatility, and broad applicability make it a key material for sustainable and precise analytical solutions.
In a time when environmental monitoring, diagnostics, and sustainability are increasingly intertwined, chitosan-based sensor technology offers a truly compelling solution.
Sources
Mourya, V. K., & Inamdar, N. N. (2008). Chitosan-modifications and applications: opportunities galore. Reactive and Functional Polymers, 68(6), 1013–1051. https://doi.org/10.1016/j.reactfunctpolym.2008.01.004
Jiao, T., Zhou, J., Guo, W., Peng, Q., Yan, X., & Zhou, J. (2023). Chitosan-Based Materials for Biosensor Applications. Polymers, 15(17), 3539. https://doi.org/10.3390/polym15173539
El-Wekil, M. M., et al. (2024). ZnS(Mn)/chitosan quantum dots for optical tetracycline detection in water and milk. Heliyon, 10(3), e16371. https://doi.org/10.1016/j.heliyon.2024.e16371
Habib, A., et al. (2017). Electrochemical DNA biosensor based on chitosan–graphene–gold nanoparticle modified electrode. Sensors, 17(5), 1132. https://doi.org/10.3390/s17051132
Kumar, N., et al. (2023). Chitosan-based electrochemical sensors for pharmaceutical and biomedical applications: A review. International Journal of Biological Macromolecules, 245, 125205. https://doi.org/10.1016/j.ijbiomac.2023.125205
Wang, J. (2006). Electrochemical biosensors: Towards point-of-care cancer diagnostics. Biosensors and Bioelectronics, 21(10), 1887–1892. https://doi.org/10.1016/j.bios.2005.10.027
First published on 7th of August 2025
Revised on 7th of August 2025