Functionalized Multi-Walled Carbon Nanotube–Based Aptasensors for Diclofenac Detection

Advances in Aptamer-Based Conjugate Recognition Techniques for the Detection of Small Molecules in Food

Small molecules are significant risk factors for causing food safety issues, posing serious threats to human health. Sensitive screening for hazards is beneficial for enhancing public security. However, traditional detection methods are unable to meet the requirements for the field screening of small molecules. Therefore, it is necessary to develop applicable methods with high levels of sensitivity and specificity to identify the small molecules. Aptamers are short-chain nucleic acids that can specifically bind to small molecules. By utilizing aptamers to enhance the performance of recognition technology, it is possible to achieve high selectivity and sensitivity levels when detecting small molecules. There have been several varieties of aptamer target recognition techniques developed to improve the ability to detect small molecules in recent years. This review focuses on the principles of detection platforms, classifies the conjugating methods between small molecules and aptamers, summarizes advancements in aptamer-based conjugate recognition techniques for the detection of small molecules in food, and seeks to provide emerging powerful tools in the field of point-of-care diagnostics.

Electrochemical Nanoaptasensor Based on Graphitic Carbon Nitride/Zirconium Dioxide/Multiwalled Carbon Nanotubes for Matrix Metalloproteinase-9 in Human Serum and Saliva

In this study, a nanocomposite was synthesized by incorporating graphitic carbon nanosheets, carboxyl-functionalized multiwalled carbon nanotubes, and zirconium oxide nanoparticles. The resulting nanocomposite was utilized for the modification of a glassy carbon electrode. Subsequently, matrix metalloproteinase aptamer (AptMMP-9) was immobilized onto the electrode surface through the application of ethyl-3-(3-(dimethylamino)propyl)carbodiimide hydrochloride-N-hydroxysuccinimide (EDC-NHS) chemistry. Morphological characterization of the nanomaterials and the nanocomposite was performed using field-emission scanning electron microscopy (FESEM). The nanocomposite substantially increased the electroactive surface area by 205%, facilitating enhanced immobilization of AptMMP-9. The efficacy of the biosensor was evaluated using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). Under optimal conditions, the fabricated sensor demonstrated a broad range of detection from 50 to 1250 pg/mL with an impressive lower limit of detection of 10.51 pg/mL. In addition, the aptasensor exhibited remarkable sensitivity, stability, excellent selectivity, reproducibility, and real-world applicability when tested with human serum and saliva samples. In summary, our developed aptasensor exhibits significant potential as an advanced biosensing tool for the point-of-care quantification of MMP-9, promising advancements in biomarker detection for practical applications.

Nanomaterials as catalysts for the sensitive and selective determination of diclofenac

Background and purpose

Diclofenac (DCF) is a non-steroidal anti-inflammatory drug possessing analgesic and antipyretic properties. It is used for the treatment of rheumatoid arthritis pain, osteoarthritis, and acute muscle pain conditions and can be administrated orally, topically or intravenously. Because of its widespread use, hydrophilicity, stability and poor degradation (bioaccumulation in the food chain), DCF is an emerging chemical contaminant that can cause adverse effects in the ecosystems. Taking into account the consumption of DCF in pharmaceutical formulations and its negative impact on the environment, the development of new sensitive, selective, cheap, fast, and online capable analytical devices is needed for on-site applications.

Experimental approach

This brief review attempts to cover the recent developments related to the use of nanomaterials as catalysts for electrochemical determination of DCF in pharmaceutical formulations, biological fluids and environmental samples.

Key results

The article aims to prove how electrochemical sensors represent reliable alternatives to conventional methods for DCF analysis.

Conclusion

The manuscript highlights the progress in the development of electrochemical sensors for DCF detection. We have analyzed numerous recent papers (mainly since 2019) on sensors developed for the quantitative determination of DCF, indicating the limit of detection, linear range, stability, reproducibility, and analytical applications. Current challenges related to the sensor design and future perspectives are outlined.