Exploring Diamond Nanoneedle Arrays: Fabrication and Emerging Applications in Biomedical Engineering

ConspectusDiamond nanomaterials have attracted significant interest in recent years due to their unique physical and chemical properties. Their exceptional mechanical strength, chemical stability, biocompatibility, and high thermal conductivity make them ideal candidates for a wide range of biomedical applications. Various formats, including nanodiamonds, diamond nanofilms, and diamond nanoneedle arrays (DNNAs), have been fabricated and used, exhibiting remarkable stability and low cytotoxicity. In particular, high-aspect-ratio and high-density DNNAs demonstrate promising potential for live cell manipulation and analysis because of their unique combination of mechanical robustness, chemical stability, and well-forged bio–nanointerfaces. On the other hand, the chemical stability of diamond material makes fabrication and functionalization challenging, which could be improved for their wider adoption.Recent research efforts have focused on the development and optimization of diamond nanoneedle fabrication techniques, aiming to achieve precise control over the geometry and array layout, as well as enhancing their functionalization for targeted drug delivery, cellular manipulation, and biosensing applications. One notable breakthrough in this area is the successful synthesis of well-ordered DNNAs through innovative fabrication processes, such as combining top-down and bottom-up approaches. These efforts have led to significant improvements in the uniformity, reproducibility, and scalability of the resulting nanoneedle structures.Leveraging their unique structure, diamond nanoneedle arrays have become a novel and versatile platform for a variety of biomedical applications. Through chemical modifications and biological functionalization of their surfaces, DNNAs offer a distinct biointerface capable of penetrating cell interiors and profiling intracellular molecules without compromising cell integrity. Furthermore, the nanoscale distribution of these nanoneedles enables DNNAs to gather heterogeneous information from ...