Chiral 2D Borophene Nanoplatelets Could Make Advanced Sensors and Implantable Medical Devices Better Than Graphene

Graphene is considered the future material because of its excellent properties and multiple applications. A recent discovery, however, reveals that a new, improved 2D material can outperform graphene's capabilities.

New Wonder Material

In 2015, scientists first synthesized the atomically thin version of boron. Known as borophene, this material is more conductive, robust, and flexible than graphene. Just recently, experts at Pennsylvania State University made borophene more practical by applying chirality to it, making the new material helpful in developing advanced sensors and implantable medical devices.

Led by materials science and engineering professor Dipanjan Pan, the research team induced chirality through a method that has never been used before on borophene. This made the material interact uniquely with various biological units like cells and protein precursors. The details of their study are discussed in the paper "Chiral Induction in 2D Borophene Nanoplatelets through Stereoselective Boron-Sulfur Conjugation."

According to Pan, borophene is an interesting material because it resembles carbon very closely, including its atomic weight and electron structure, but with more exceptional properties. The research team claims that this is the first study conducted to understand the biological interactions of borophene and the first report of applying chirality to borophene structures.

Borophene is a structurally polymorphic material, which means that its boron atoms can be arranged in various configurations to give different shapes and properties. It is almost like the way the same set of Lego blocks can be arranged to form other structures. This property allows the scientists to "tune" borophene to give it different properties, such as chirality.

Since borophene has remarkable ability as a substrate for implantable sensors, the researchers investigated their behavior when exposed to cells. The study shows that different polymorphic structures of borophene interact with cells in a different way. It was also revealed that the cellular internalization pathways of this material are uniquely dependent on their structures.

Pan and colleagues synthesized borophene platelets using solution-state synthesis, similar to the cellular components found in blood. They subjected the boron powders to high-energy sound waves to impart chirality and mixed the platelets with various amino acids in a liquid.

It was discovered that certain amino acids, such as cysteine, bind to borophnere in particular locations, depending on their chiral handedness. Upon exposing and spiralizing borophene platelets to mammalian cells, the researchers noticed that their handedness changed how they interacted with cell membranes and entered cells.

What is Chirality?

In chemistry, a type of isomer called the mirror-image stereoisomer is a non-superimposable set of two molecules that are mirror images of one another. The existence of such molecules are determined by chirality, a property of a molecule which results from its structure. The term "chiral" comes from the Greek word for hand, since the human hands are a good example of chirality.

Chirality refers to similar but not identical physicality, such as left and right hands. In molecules, chirality makes it possible to produce biological or chemical entities that exist in two versions without being perfectly matched, such as a left and right glove. These units can precisely mirror each other, but a left glove will never fit the right hand as well as it fits the left hand.