Silaffin primary structure and its effects on the precipitation morphology of titanium dioxide

Abstract

Inorganic oxides exhibit numerous applications influenced by particle size and morphology. While industrial methods for forming oxides involve harsh conditions, nature has the ability to form intricate structures of silicon dioxide (silica) using small peptides and polyamines under environmentally friendly conditions. Recent research has demonstrated that these biomaterials will precipitate other inorganic oxides, such as titanium dioxide (titania). Using the diatom-derived R5 peptide, new peptides with systematic changes (e.g., truncation and substitution) in the R5 primary structure were surveyed for reactivities and the impact on the morphology of the titania. The results demonstrated that (i) basic residues are vital to initiating the reaction, and a minimum local concentration is necessary to sustain the precipitation, (ii) residues containing hydroxyl side chains are important to imparting morphological control on the precipitate, and (iii) buffer conditions can dramatically alter both precipitation and morphology.

TiBALDH as a precursor for biomimetic TiO2 synthesis: stability aspects in aqueous media

“…This behaviour agreed with the reported by other authors that claim that peptides in presence of PB are able to induce TiO 2 biomineralization from TiBALDH. 27,33,[40][41][42][43] However, the nal product usually is amorphous and contaminated with phosphorous, in our case, we observed the formation of a precipitate, which was not further analysed because is out of the scope of this work. Also, the amount of Ti(IV) free (soluble) was quantied by colorimetric assay, 32 as is shown in Fig.…”

“…Although the phosphate ions are able to react with TiBALDH being the most common system used for biomineralization reactions, their inuence is a tricky issue. In some reports, it was mentioned that phosphate ions promote TiBALDH precipitation, 33,40,41 while in others no changes were reported using only PB and the mineralizing activity was attributed exclusively to the biomolecule employed. 27,42,43 To establish the conditions where the PB has not effect TiBALDH stability we monitored the change in the particle size of solutions to different concentrations of TiBALDH and PB.…”

Serine–Lysine Peptides as Mediators for the Production of Titanium Dioxide: Investigating the Effects of Primary and Secondary Structures Using Solid-State NMR Spectroscopy and DFT Calculations

“…Biomimetic approaches are being applied to the production of other oxides, with a specific emphasis on TiO 2 . ,,,− Many of these methods include the use of lysine-rich peptides or small organic amines and have shown the importance of clusters of lysine (and arginine) residues in these SiO 2 - and TiO 2 -precipitating systems. ,,, …”

“…19,21,38,43−50 Many of these methods include the use of lysine-rich peptides or small organic amines and have shown the importance of clusters of lysine (and arginine) residues in these SiO 2 -and TiO 2 -precipitating systems. 30,31,51,52 Here, we investigate the effects of primary structure of serine−lysine (S−K) peptides on TiO 2 precipitation. The relative numbers of S and K residues within the primary sequence result in TiO 2 of varied size and morphology.…”

Síntesis de óxido de titanio mesoporoso usando como plantilla el bacteriógrafo M13

“…Los resultados de reactividad con los diferentes sistemas amortiguadores se muestran en la Figura 4.3, donde los únicos sistemas que presentaron una variación en el tamaño de partícula del TiBALDH fueron fosfatos (PB) y pH 8.5, lo que sugiere que hubo alguna reacción química con el medio. Existen varios reportes donde se emplea el sistema amortiguador de fosfatos para las reacciones de biomineralización con péptidos, sin embargo, como se observa en los experimentos realizados aquí, el TiBALDH reacciona en presencia de fosfatos incluso a concentraciones tan bajas como 0.01 M. Esto es importante ya que pocos trabajos donde biomineralizan TiO2 usando TiBALDH mencionan su reactividad, [85][86][87] mientras que otros autores, a pesar de usar concentraciones de fosfatos suficientes para reaccionar con TiBALDH, no mencionan nada al respecto. 61,[82][83][84][88][89][90] Cuando se utilizó el sistema amortiguador Tris, según DLS, el tamaño de partícula del TiBALDH se mantuvo constante (Figura 4.2).…”