Designed 2D protein crystals as dynamic molecular gatekeepers for a solid-state device

Area of Science:

• Biomolecular Engineering
• Materials Science
• Chemical Sensing

Background:

• Living cells' dynamic protein structures enable environmental responsiveness, motivating artificial protein assembly design.
• Current designed protein assemblies lack integration into macroscale devices for practical applications.

Purpose of the Study:

• To engineer a 2D crystalline protein assembly capable of selective molecular gating in response to a chemical trigger.
• To demonstrate the integration of this protein assembly into a solid-state device for enhanced sensing capabilities.

Main Methods:

• Engineered a 2D crystalline assembly of L-rhamnulose-1-phosphate aldolase (^CEERhuA) using cobalt(II) coordination bonds.
• Utilized a chemical trigger, hydrogen cyanide gas (HCN(g)), to induce conformational changes in the protein crystals.
• Layered the 2D ^CEERhuA crystal onto a mesoporous silicon (pSi) photonic crystal optical sensor.

Main Results:

• ^CEERhuA crystals transitioned from a closed state (<1 nm pores) to an ajar state (~4 nm pores) upon exposure to HCN(g).
• The 2D ^CEERhuA layer selectively blocked interferents, preventing false positives on the pSi sensor.
• The protein crystal layer opened upon exposure to low parts-per-million (ppm) levels of HCN(g), enabling analyte detection.

Conclusions:

• Designed protein assemblies can function as dynamic, switchable components in solid-state devices.
• This work demonstrates a novel approach for creating responsive materials for chemical sensing in non-aqueous environments.
• The ^CEERhuA protein crystals offer a promising platform for advanced sensor technology.