Diatoms have the ability to generate highly ornamented nanostructured silicified cell walls under ambient conditions and without harsh chemicals, yet the molecular mechanisms underlying biosilification are still not well understood. The idea of this study is to mimic silica biomineralization of diatom cell walls that may provide the key to the development of new routes towards novel tailor-made silicas. Here the ability of R5 peptide, a peptide from the silaffin-1 protein derived from diatom species of Cylindrotheca fusiformis, to generate silica nanostructure in vitro was investigated. The R5 peptide was synthesized using Fmoc Solid-Phase Peptide Synthesis and purified using reverse phase high performance liquid chromatography. MALDI analysis showed that the peptide was successfully synthesis. With the application of silicic acid as a silica precursor and the peptide as catalyse, the formation of silica nanostructure was achieved, AFM analysis of the precipitated silica from the mixture of silicic acid and the peptide revealed the nanostructure of silica spheres ranging between 50 - 300 nm in diameter. Silica precipitate was not obtained in the absence of R5 (negative control) and when the silicic acid was mixed with poly-L-lysine (positive control), a network of large aggregates of uniform size of silica spheres of about 100 nm in diameter was observed.