Aptasensor-encapsulating semi-permeable proteinosomes for direct target detection in non-treated biofluids

Area of Science:

• Biomolecular Engineering
• Nanotechnology
• Molecular Diagnostics

Background:

• Direct biomarker detection in biofluids enhances molecular diagnostics efficiency.
• Aptasensors offer broad detection capabilities but are vulnerable to degradation and aggregation in clinical samples.
• Nucleases and charged proteins in biofluids compromise aptasensor performance.

Purpose of the Study:

• To develop a method for protecting aptasensors for direct use in untreated clinical samples.
• To enable sensitive and selective detection of small molecules in complex biological matrices.
• To demonstrate the utility of proteinosomes as protective microcapsules for aptasensors.

Main Methods:

• Aptasensors were encapsulated within proteinosomes, protein-based liposome mimics.
• Proteinosome membranes, formed from serum albumin, provided semi-permeability and antifouling properties.
• Structure-switching aptamers for estradiol, dopamine, and cocaine were tested for performance within proteinosomes.

Main Results:

• Encapsulated aptasensors successfully detected small molecules in 100% unpurified serum.
• Proteinosomes prevented aptasensor degradation by nucleases and aggregation by proteins, maintaining high affinity and specificity.
• DNA aptasensors remained intact for over 18 hours in serum and concentrated DNase solutions.
• Simultaneous real-time sensing of two targets was achieved using proteinosome compartmentalization.

Conclusions:

• Proteinosome encapsulation shields aptasensors, enabling optimal performance in challenging biological environments like serum.
• This approach overcomes limitations of aptasensor degradation and aggregation, paving the way for direct molecular diagnostics.
• The technology demonstrates significant potential for sensitive, selective, and multiplexed detection of small molecules in clinical samples.