The role of aptamers in biomarker visualization and analysis

Aptamers are nucleic acid molecules, either DNA (deoxyribonucleic acid) or RNA (ribonucleic acid), which are used in medicine, biomedical research and analytical biochemistry and chemistry.
They are distinguished by their ability to bind selectively and strongly to specific targets, be they proteins, small chemical compounds or even cells.

Aptamer design begins in the Novaptech laboratory, where researchers use a process called SELEX (Systematic Evolution of Ligands by EXponential enrichment) to isolate aptamers with a particularly high affinity for the desired target. This is a complex, multi-step process:

1. In vitro selection : The selection process begins with a random library of oligonucleotides (DNA or RNA oligomers) containing billions of different sequences. These sequences are exposed to the target one wishes to detect or target. The aptamers that bind to the target are then recovered.

 
2. Amplification : The sequences that bound to the target are amplified by PCR (polymerase chain reaction) to produce a larger quantity of candidates.

3. Repeating the process : This selection cycle is repeated several times to improve the affinity and specificity of the candidates towards the target.

 
4. Validation : The final candidates obtained are then tested to confirm their ability to bind specifically to the target. Oligonucleotides that meet the specificity and affinity criteria are aptamers.

 
This in vitro selection process enables researchers at Novaptech to generate tailor-made aptamers for virtually any target. Once obtained, aptamers can be used in a variety of ways, including the detection of the target in various samples, inhibition of the activity of specific
proteins or even targeted drug delivery.

Visualization of known biomarkers using aptamers

· Production of labeled aptamers : Selected aptamers are labeled with fluorescent molecules, enzymes or nanoparticles to facilitate their subsequent detection.
· Interaction with the target : When exposed to a biological sample containing the desired target, aptamers bind specifically to that target.
· Detection and quantification : Aptamers bound to the target are then detected and quantified. This can be done using a variety of methods, such as colorimetry, fluorescence, electrochemistry or PCR, depending on how the aptamers were labeled.
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· Oligonucleotide aptamers selected for their high binding affinity to specific targets, are revolutionizing the field of biomolecular detection, thanks to their flexibility, specificity and ease of modification.
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· They offer a validated alternative to antibodies in a variety of analytical applications, notably in the development of biosensors.
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· The specificity of aptamers derives from their ability to fold into three-dimensional structures enabling strong, specific binding to their target, whether small molecules, proteins or even whole cells.
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· This specificity is essential for detection and analytical applications, where distinguishing between similar molecules provides precise diagnosis.
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· The versatility of aptamers is also a major asset. Thanks to chemical modifications, it is possible to improve their stability under physiological conditions, increase their in vivo half-life or endow them with functional groups facilitating their immobilization on sensor surfaces or labeling with fluorescent or electrochemical probes.
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· The development of aptamer-based biosensors benefits directly from these features. Aptamers can be integrated into detection systems that translate molecular recognition into a measurable electrical or optical signal.
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· This signal transduction enables precise quantification of the target in complex samples, paving the way for rapid, sensitive and inexpensive diagnostics for a wide range of applications, from environmental monitoring to early disease diagnostic.
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· The future of aptamers in biosensors is very promising, and through its research and development process, Novaptech aims to further improve the sensitivity and specificity of detection systems.
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· The engineering of aptamers for targeted applications could revolutionize the diagnosis and treatment of diseases, as well as the detection of analytes further affirming their indispensable role in the biomedical field.
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Advantages of aptamers over other detection tools

Aptamers offer several significant advantages over other biomarker visualization and analytical tools
· High selectivity : Aptamers are designed to bind extremely specifically to their target, minimizing false positives and interference.
· Ease of production : Aptamers can be produced in large quantities, economically, relatively simply and reproducibly.
· Stability : Unlike proteins, aptamers are thermally stable, making them ideal for use in a variety of environments.
· Versatility : Aptamers can be used to detect a wide range of biomarkers, from proteins to small molecules to cells.

Examples of successful biomarker visualization using aptamers

· Detection of cancer proteins : Aptamers have been developed to detect specific proteins associated with cancer, such as epidermal growth factor (EGF) in breast cancer. These aptamers enable early detection of the disease.
· Infectious disease monitoring : Aptamers have been used to detect pathogens such as HIV, dengue fever virus and SARS-CoV-2 (responsible for COVID-19), enabling rapid and accurate diagnosis, notably through the use of rapid test kits and devices.
· Detection of cardiac biomarkers : Aptamers have been developed to detect cardiac biomarkers such as troponin, which is essential for diagnosing heart problems.
Aptamers represent a significant advance in biomarker detection and analysis in medicine. Their high specificity, versatility and ease of production make them powerful tools for early disease detection, personalized treatment and biomedical research.
Thanks to their capacity and Novaptech’s expertise, aptamers represent a major advance in the visualization and analysis of biomarkers in medicine.