Highly Efficient Fumed Silica Nanoparticles for Peptide Bond Formation: Converting Alanine to Alanine Anhydride

Abstract

In this work, thermal condensation of alanine adsorbed on fumed silica nanoparticles is investigated using thermal analysis and multiple spectroscopic techniques, including infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopies. Thermal analysis shows that adsorbed alanine can undergo thermal condensation, forming peptide bonds within a short time period and at a lower temperature (∼170 °C) on fumed silica nanoparticle surfaces than that in bulk (∼210 °C). Spectroscopic results further show that alanine is converted to alanine anhydride with a yield of 98.8% during thermal condensation. After comparing peptide formation on solution-derived colloidal silica nanoparticles, it is found that fumed silica nanoparticles show much better efficiency and selectivity than solution-derived colloidal silica nanoparticles for synthesizing alanine anhydride. Furthermore, Raman spectroscopy provides evidence that the high efficiency for fumed silica nanoparticles is likely related to their unique surface features: the intrinsic high population of strained ring structures present at the surface. This work indicates the great potential of fumed silica nanoparticles in synthesizing peptides with high efficiency and selectivity.

En Route to a Heterogeneous Catalytic Direct Peptide Bond Formation by Zr-Based Metal–Organic Framework Catalysts

“…Prior works addressing the formation of peptide bonds through heterogeneous catalysis have been mostly related to the prebiotic formation of peptides. − They provided extensive mechanistic understanding on the interaction between amino acids and peptides with oxide surfaces, particularly silica, and the formation of peptide bonds in these environments. − The formation of peptide products has been generally observed at temperatures which exceeded 100 °C. Moreover, products were frequently generated as mixtures and were usually not isolated and purified, thereby drastically limiting the synthetic potential of these reactions for preparative organic chemistry . Therefore, in view of the great structural versatility and stability of MOFs, , the increasing utility of Zr-MOFs in catalysis, and the lack of more general heterogeneous catalysts for the catalytic direct formation of amide and peptide products, ,− , repurpose of Zr-MOFs from hydrolysis to formation of peptide bonds would greatly contribute to develop a truly sustainable and practical peptide bond formation method.…”

“…Moreover, products were frequently generated as mixtures and were usually not isolated and purified, thereby drastically limiting the synthetic potential of these reactions for preparative organic chemistry. 58 Therefore, in view of the great structural versatility and stability of MOFs, 59,60 the increasing utility of Zr-MOFs in catalysis, 61 and the lack of more general heterogeneous catalysts for the catalytic direct formation of amide and peptide products, 10,[19][20][21][22]43 repurpose of Zr-MOFs from hydrolysis to formation of peptide bonds would greatly contribute to develop a truly sustainable and practical peptide bond formation method. In this context, we report the formation of peptide bonds catalyzed by UiO-66 MOF.…”

Rheological, physicochemical, and microstructural properties of asphalt binder modified by fumed silica nanoparticles

“…Guo et al 32 reported on fumed silica nanoparticles (FSN) on a large scale. FSN represent a synthetically produced nanomaterial that is composed of an amorphous structure in a nano size scale and a large surface area.…”

Characterizing gold nanoparticles by NMR spectroscopy

“…Until recently, only the structures of Au 23 (SC 6 H 11 ) 16 , Au 25 (PET) 18 , Au 25 (SEt) 18 , Au 28 (TBBT) 20 , Au 36 (SPh‐tBu) 24 , Au 38 (SR) 24 , and Au 102 (p‐MBA) 44 have been successfully determined by X‐ray crystallography. Comparing with all these techniques, nuclear magnetic resonance (NMR) spectroscopy has been demonstrated to be a universal and versatile technique for characterization of nanomaterials . One‐dimensional/multidimensional NMR spectroscopy combined with homonuclear/heteronuclear NMR spectroscopy provides considerable methods for characterizing nanostructures including purity, ligand density, and surface chemistry .…”