In nanobiotechnology, a peptoid

nanosheet A nanosheet is a two-dimensional nanostructure with thickness in a scale ranging from 1 to 100 nm. A typical example of a nanosheet is graphene, the thinnest two-dimensional material (0.34 nm) in the world. It consists of a single layer o ...

is a synthetic protein structure made from

peptoid Peptoids (root from the Greek language, Greek πεπτός, ''peptós'' "digested"; derived from πέσσειν, ''péssein'' "to digest" and the Greek-derived suffix -oid meaning "like, like that of, thing like a ______," ), or poly-''N''-substit ...

s. Peptoid nanosheets have a thickness of about three nanometers and a length of up to 100 micrometers, meaning that they have a two-dimensional, flat shape that resembles paper on the nanoscale. This makes them one of the thinnest known two-dimensional organic

crystalline A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

materials with an area to thickness ratio of greater than 10⁹ nm. Peptoid nanosheets were discovered in the laboratory of Dr. Ron Zuckermann at the Lawrence Berkeley National Laboratory in 2010. Due to the ability to customize peptoids and therefore the properties of the peptoid nanosheet, it has possible applications in the areas of drug and small molecule delivery and

biosensing A biosensor is an analytical device, used for the detection of a chemical substance, that combines a biological component with a physicochemical detector. The ''sensitive biological element'', e.g. tissue, microorganisms, organelles, cell recep ...

Synthesis

For assembly, a purified amphiphilic polypeptoid of specific sequence is dissolved in aqueous solution. These form a monolayer ( Langmuir–Blodgett film) on the air-water interface with their hydrophobic side chains oriented in air and hydrophilic side chains in the water. When this mono-layer is shrunk, it buckles into a bilayer with the hydrophobic groups forming the interior core of the peptoid nanosheet. This method has been standardized in the Zuckermann laboratory by repetitively tilting vials of peptoid solution at 85° before returning the vials to the upright position. This repetitive vial “rocking” motion lessens the interfacial area of the air-water interface inside the vial, compressing the peptoid mono-layer by a factor of four and causing the mono-layer to buckle into peptoid nanosheets. Using this method, nanosheets are produced in high yield, and 95% of the peptoid polymer starting material is efficiently converted into peptoid nanosheets after rocking the vials several hundred times.

Applications

Peptoid nanosheets have a very high surface area, which can be readily functionalized to serve as a platform for sensing and templating. Also, their hydrophobic interiors can accommodate hydrophobic small molecule cargos, which have been demonstrated by the sequestration of

Nile red The Nile, , Bohairic , lg, Kiira , Nobiin: Áman Dawū is a major north-flowing river in northeastern Africa. It flows into the Mediterranean Sea. The Nile is the longest river in Africa and has historically been considered the longest rive ...

when this dye was injected into an aqueous solution of the peptoid nanosheets. For these reasons, the hydrophobic interior of the 2D nanosheets could be an attractive platform for loading or embedding hydrophobic cargo, such as drug molecules,

fluorophores A fluorophore (or fluorochrome, similarly to a chromophore) is a fluorescent chemical compound that can re-emit light upon light excitation. Fluorophores typically contain several combined aromatic groups, or planar or cyclic molecules with sev ...

aromatic In chemistry, aromaticity is a chemical property of cyclic ( ring-shaped), ''typically'' planar (flat) molecular structures with pi bonds in resonance (those containing delocalized electrons) that gives increased stability compared to satur ...

compounds, and metal nanoparticles.

References

{{reflist Protein structure Two-dimensional nanomaterials Crystals Organic chemistry

Synthesis

Applications

See also

References