Biosensors have become indispensable tools across medicine, environmental monitoring, food safety, and biotechnology. Their ability to detect biological or chemical targets with high sensitivity depends not only on the sensing element itself but also on the materials that protect, stabilize, and functionalize it. As biosensors are increasingly deployed in complex or harsh environments, the design of suitable coatings has become a central scientific challenge.
A recently published review in Coatings (MDPI, 2024) provides a comprehensive overview of how different coating strategies influence biosensor performance. It examines the materials, surface treatments, and functional layers that support reliable signal transduction, enhance biorecognition, and extend sensor lifetime. The review highlights how coatings are no longer passive protective films but active components that shape the sensitivity, selectivity, and operational stability of modern biosensing platforms.
The review is discussing a wide spectrum of polymeric and
hybrid coatings — from conductive polymers and nanocomposites to bio‑inspired
films and inorganic layers — and analyse how each contributes to sensor
functionality. Coatings can reduce electrode impedance, improve charge
transfer, and enhance the signal‑to‑noise ratio, all of which are essential for
achieving high sensitivity. At the same time, they stabilize immobilized
biomolecules, reduce nonspecific adsorption, and create microenvironments that
preserve biological activity.
A recurring theme is the importance of surface chemistry and
deposition control. Subtle differences in hydrophilicity, charge, roughness, or
functional groups can dramatically influence how biomolecules attach and how
signals propagate. The review also emphasizes the need for more standardized
deposition protocols, particularly for electrodeposition and surface
functionalization, as reproducibility remains a bottleneck when translating lab‑scale
coatings into reliable devices.
Many biosensors suffer from fouling, degradation, or loss of
biological activity over time. The review highlights protective layers that
mitigate these issues, especially for implantable or wearable devices where
biocompatibility and mechanical compliance are crucial. Conductive polymers,
for example, offer excellent electrical properties but may lack mechanical
robustness or stable conductivity over long periods. Balancing conductivity
with flexibility, stability, and biological safety remains a central design
challenge.
Smart and sustainable coatings are gaining attention. Stimuli‑responsive hydrogels, polymer brushes, and electroactive films can adapt to local conditions, modulate transport, or even perform partial self‑cleaning cycles to counteract fouling and baseline drift. Self-healing coatings based on dynamic covalent bonds or supramolecular interactions are an emerging technology for applications where repeated bending or micromotion could cause cracking or delamination. In parallel, greener strategies — including bio‑based polymers, biodegradable materials, and waste‑derived biomaterials — are becoming increasingly relevant, especially for disposable or single‑use biosensor platforms. These approaches align with broader sustainability goals and encourage lower‑impact processing routes such as water‑based formulations, mild crosslinking, and electrodeposition‑based methods.
Biosensors are central to many of today’s most pressing
challenges: early disease detection, environmental monitoring, food quality
control, and rapid diagnostics. Improving their stability, sensitivity, and
robustness directly enhances our ability to measure and understand biological
and chemical processes.
Coatings play a crucial role in this progress. By tailoring
the interface between the biological recognition element and the external
environment, researchers can design sensors that are more accurate, more
durable, and more adaptable to complex applications. The integration of smart,
biocompatible, and sustainable coatings reflects the increasingly
interdisciplinary nature of the field, bringing together materials science,
chemistry, nanotechnology, and biotechnology. By mapping these emerging
directions, the review helps the research community refine its priorities and
explore new pathways toward resilient, environmentally responsible biosensing
technologies.
