Highly sensitive optical biosensor for thrombin based on structure switching aptamer-luminescent silica nanoparticles

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Alpha-thrombin is a key biomarker in various physiological and pathological processes.
• Developing sensitive and selective detection methods for alpha-thrombin is crucial for early disease diagnosis and monitoring.
• Existing detection methods may lack the required sensitivity, selectivity, or applicability in complex biological matrices.

Purpose of the Study:

• To construct a sensitive and selective optical sensor system for the detection of human alpha-thrombin.
• To functionalize luminescent silica nanoparticles (SiNPs) with a thrombin-binding aptamer for enhanced detection.
• To investigate the mechanism of signal transduction via Förster Resonance Energy Transfer (FRET).

Main Methods:

• Preparation of surface-functionalized luminescent [Ru(dpsphen)3](4-) ion-doped silica nanoparticles (SiNPs).
• Conjugation of a DABCYL quencher-labeled thrombin-binding aptamer to SiNPs using BS(3) cross-linker.
• Utilizing the conformational change of the aptamer upon thrombin binding to induce a FRET mechanism and alter luminescence intensity.

Main Results:

• The developed SiNPs-aptamer system demonstrated sensitive detection of thrombin down to 4 nM.
• The sensor exhibited high selectivity for thrombin compared to other proteins.
• The FRET mechanism effectively translated the binding event into a measurable change in luminescence intensity.

Conclusions:

• The aptamer-SiNPs conjugate serves as a highly sensitive and selective optical sensor for human alpha-thrombin.
• This system shows promise for detecting thrombin in complex biological media, including the presence of Bovine Serum Albumin (BSA).
• The study highlights the potential of aptamer-functionalized nanoparticles in developing advanced biosensing platforms.