Functionalization of the living diatom Thalassiosira weissflogii with thiol moieties

Abstract

Biomineralization processes identified within diatoms have inspired the design of synthetic silica structures in vitro using alkoxysilane precursors. Here we explore the use of the machinery within the living diatom to fabricate organo-silica constructs using a combination of alkoxysilane and organoalkoxysilane precursors. We report on the incorporation of thiol moieties into the diatom during frustule synthesis. Formation of valves within the parent diatom is monitored using fluorescence microscopy, and the modification of the chemical composition of the diatom is confirmed using energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and 29 Si-nuclear magnetic resonance spectroscopy. Chemical modification is achieved without loss of the nano-scale architectural features of the frustule. Extension of this work may allow the chemistry of the diatom to be tailored during synthesis.

Diatoms: a biotemplating approach to fabricating drug delivery reservoirs

“…Significant progress has been made over the past decade in understanding the mechanisms associated with the silica deposition vesicle [8][9][10][11] and the associated proteins involved in the valve synthesis pathway [52][53][54]. Unraveling these processes further will provide a deeper understanding of diatom development on a mechanistic level, which in turn provides mechanistic insight for chemical modifications during frustule synthesis [55,56].…”

Biogenic nanomaterials from photosynthetic microorganisms

“…For the in vivo functionalization, Lang et al [33 ] replaced the soluble silica substrate for frustule formation, Si(OH) 4 , with a 3:1 molar ratio of tetramethoxysilane (TMOS) and 3-mercaptopropyltrimethoxysilane (MPTMS). The TMOS and MPTMS are hydrolyzed and taken up by the cell culture which results in the in vivo functionalization of the frustule surface with thiol moieties [33 ]. The thiol groups could potentially be further functionalized as was demonstrated in previous work [31].…”

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…Using in vitro/vivo specific modification strategies, the T. weissflogii diatom was also successfully modified with thiol groups. [75,76] These results are highly significant, as they indicate a strong potential for diatoms to be conferred with therapeutic properties, as the photocatalytic ability of TiO 2 was reported to induce oxidative DNA strand breakage [77] and cancer cell depletion, [78] whilst the introduction of thiol groups allows further functionalization and enhancement in protein stability. [79] An organic solvent/covalent cross-linking free strategy is a notable example of simultaneous attachment of antibodies and drug molecules to the surface of the diatom-based biosilica.…”