Recent advances in bacterial detection targeting proteins: Aptamer sensors

Protein molecule

The recent bacterial detection are categorizes in 3 strategies acording to major biomarker types: protein, genetic, and enzymatic. This article will expose the protein biomarker.

Some protein has been identified due to their relevance as ingredient in food processing once they have potential significance of modification properties in food products industry.

Detection

Protein biomarkers encompass surface antigens, toxins, and other secreted or structural proteins. Typically relies on selective binding interactions or analysis of protein mass:

1. immunological assays (antibody-based detection),

2. aptamer-based sensors,

3. mass spectrometry techniques.

Challenges

Protein markers may show limited sensitivity for low-titer pathogens and cross-reactivity in complex matrices.

Advantages

Often recognizing intact bacteria or specific molecules without the need for nucleic acid extraction or amplification.

Aptamers are easily modified with fluorescent groups, which expand their applications.

Aptamers sensors

Aptamers are synthetic single-stranded DNA or RNA molecules that fold into unique 3D structures, enabling high-affinity and high-specificity binding to various targets. Selected in vitro through the systematic evolution of ligands by exponential enrichment (SELEX) process, aptamers can be designed to recognize bacterial proteins, toxins, or whole cells.

Compared to antibodies, aptamers offer several advantages: chemical synthesis, low production cost, ease of modification, and superior stability under variable conditions. Their ability to target cell surface motifs also enables direct capture of intact bacteria from complex samples.

Upon binding to the bacteria, the aptamer may undergo a conformational change that separates the fluorophore from a quencher, resulting in a fluorescence increase. This principle is often termed a "molecular beacon" strategy.

Types of Apatamer Techiniques:

• Aptamer-Based Fluorescence Sensors

• Aptamer-Based Colorimetric Sensors

• Aptamer-Based Electrochemical Sensors

• Aptamer-Based Surface-enhanced Raman Scattering (SERS) Method

In summary...

... aptamer-based detection offers a versatile and promising platform for bacterial sensing, with advantages such as high stability, reusability, and design flexibility. Aptamers can be easily engineered through truncation or functional modification to enhance binding or enable signal readout. However, challenges remain in ensuring aptamer stability and specificity in complex matrices such as blood or wastewater, where nonspecific interactions or degradation can compromise performance.

Reference:

H. Chen, J. Xiao, B. Diao, S. Zheng, H. Shao, L. Liu. Recent advances in bacterial detection techniques targeting genetic, protein, and enzymatic biomarkers. Journal of Pharmaceutical Analysis. https://doi.org/10.1016/j.jpha.2026.101584.