Diatom presents a promising frontier in nanotechnology for modern biomedical applications and material science. Diatoms possess a unique feature in their intricate silica-based cell walls, frustules, which shows high surface area, porosity and nanoscale precision which closely resemble artificially synthesized porous silica and offers a lucrative and sustainable alternative for diverse technological applications. Diatom biosilica holds distinctive properties such as chemical stability, thermal resistance, biocompatibility and tailored surface chemistry which makes it exceptionally suitable for nanomedicine, microfluidics, biosensing and photonics. Furthermore, nanoparticles synthesized using diatoms serve as efficient platforms for various applications including targeted therapeutics like drug and gene delivery and photodynamic therapy because of their distinctive morphology and biofunctionalization potential. The capability of diatoms to synthesize nanoscale architectures through biological processes serves an ideal model for energy-efficient and scalable nanofabrication which can surpass conventional synthetic methods. This chapter focuses on various aspects of diatom frustule offering significant insights for designing biomaterial, carving path for remarkable innovations in applications such as renewable energy technologies, bioimaging and molecular filtration. Harnessing the potential of diatom in formulating nanostructures which could generate new prospects in modern technologies, illustrating their importance in next-generation nanotechnology.