Advancements in two-dimensional boron nitride nanostructures: properties, preparation methods, and their biomedical applications

Novel boron nitride (BN) nanostructures with varied dimensionalities and unique and extraordinary qualities like exceptional mechanical properties, high thermal conductivity, excellent chemical properties have applications in diverse and promising fields, encompassing healthcare, environment, and energy. Amongst the boron nitride nanostructures, two-dimensional BN sheets have been extensively explored by researchers due to their planar topography, which confers them with distinct qualities in terms of chemical, physical, optical, and electronic properties. 2D boron nanostructures have a significant surface-to-volume ratio that enables their enhanced contact with cells and biomolecules, making them appealing candidates for biological applications. This article aims to completely present the latest advances in the development of two-dimensional boron nanostructures, most importantly nanosheets. The properties and different synthesis processes and modifications used for developing 2D boron nanosheets are summarized. We provide a detailed explanation of the unique features of 2D boron nanosheets that enable their usage in biomedical applications like in the field of drug delivery, cancer theranostics, bioimaging, and biosensing. Finally, the prospects of 2D boron nanosheets and their future challenges are discussed. It is anticipated that this review will encourage more developments in the field of 2D boron nanostructures for potential future applications.