Single-stranded DNA-encoded gold nanoparticles enable dynamic "nano" molecular reactions

[ Instrument Network Instrument R & D ] Recently, the Laboratory of Physical Biology of the Center for Light Source Science, Shanghai Institutes of Advanced Research, Chinese Academy of Sciences, Shanghai Institute of Applied Physics, Chinese Academy of Sciences and Shanghai Jiaotong University have jointly developed a method for encoding gold nanoparticles with single-stranded DNA And realized the dynamic "nano" molecular reaction. By designing a multi-block single-stranded DNA sequence, this method can impart discrete valence states and orthogonal valence bonds of gold nanoparticles to similar atoms. These "nano" atoms can be assembled into anisotropic "nano" molecules through the reaction of DNA molecules, and then produce "nano" molecular reactions.

Deoxyribonucleic acid (English DeoxyriboNucleic Acid, abbreviated as DNA) is one of the four types of nucleic acids contained in biological cells. DNA carries the genetic information necessary to synthesize RNA and proteins, and is an essential biological macromolecule for the development and normal operation of organisms. DNA is a large polymer of deoxynucleotides. Deoxynucleotides are composed of bases, deoxyribose, and phosphate. There are four kinds of bases: adenine (A), guanine (G), thymine (T) and cytosine (C).

In the DNA molecular structure, two polydeoxynucleotide strands are coiled around a common central axis, forming a double helix structure. The deoxyribose-phosphate chain is on the outside of the helix and the base is on the inside. The two polydeoxynucleotide strands are complementary in opposite directions, and are connected by base pairing formed by hydrogen bonding between bases to form a fairly stable combination.

The precise dynamic regulation of molecules or materials at the micro-scale reflects human's ability to recognize and manipulate the micro-world. However, the precise dynamic regulation of nanoparticles remains challenging. In living organisms, biomolecular machines have extremely delicate structures and are controlled by strict time and air-conditioning. The spatiotemporal arrangement information of these complex structures is encoded by a one-dimensional DNA molecule sequence. Inspired by this, the team proposed to use multi-block single-stranded DNA sequences to encode the valence bond information on the surface of gold nanoparticles, and then build "nano" atoms with discrete valence states and orthogonal valence bonds.

Nanoparticles refer to particles with a particle size between 1-100nm (nanoparticles are also called ultrafine particles). It belongs to the category of colloidal particle size. They are in the transition zone between atom clusters and macroscopic objects, between the microscopic system and the macroscopic system, and they are a group composed of a small number of atoms or molecules. Therefore, they are neither a typical microscopic system nor a typical macroscopic system.

Nanoparticles have many active centers on the surface, which provides the necessary conditions for nanoparticles to be used as catalysts. At present, the use of nanoparticles for catalytic reactions can directly use nanoparticles such as platinum black, silver, alumina, iron oxide, etc. as catalysts in the oxidation, reduction and synthesis of high molecular polymers, which can greatly improve the reaction efficiency and use nano nickel powder. As a rocket solid fuel reaction catalyst, the combustion efficiency can be increased by 100 times; the catalytic reaction also shows selectivity. For example, the oxidation reaction of propionaldehyde with a silicon-supported nickel catalyst shows that the selectivity changes sharply when the particle size of nickel is below 5nm, and the aldehyde is decomposed. Controlled, the selectivity to alcohol production rises sharply.

Based on these "nano" atoms, they can self-assemble through orthogonal DNA pairs to form "nano" molecules with precise particle numbers and anisotropy. And these "nano" molecules still have the ability to rearrange after synthesis. Therefore, the use of DNA strand substitution reactions can trigger dynamic "bonding" and "breaking of bonds", simulating a variety of basic chemical reactions such as addition, decomposition, substitution and metathesis. They also designed a single-grain logic gate based on this system and integrated it into a "voting machine" logic circuit. When the majority of the input signals are positive ("more than half of the votes"), the "nano" molecules dissociate; when only a few signals are positive, the "nano" molecules do not dissociate. These precisely assembled nanometer "atoms" and "molecules" with dynamic response capabilities are expected to be applied in the fields of bio-intelligent diagnosis and treatment.

Source: Shanghai Advanced Institute, Encyclopedia