Synthesis of nanostructured silica/hydroxyapatite hybrid particles containing amphiphilic triblock copolymer for effectively controlling hydration layer structures with cytocompatibility

2020 ◽  
Vol 8 (7) ◽  
pp. 1524-1537 ◽  
Author(s):  
Shota Yamada ◽  
Satoshi Motozuka ◽  
Motohiro Tagaya
Keyword(s):  
Mesoporous Silica ◽  
Triblock Copolymer ◽  
Secondary Structures ◽  
Hybrid Particles ◽  
Hydration Layer ◽  
Protein Secondary Structures ◽  
Amphiphilic Triblock Copolymer ◽  
Layer Structures ◽  
Nanostructured Silica

This is the first successful report to synthesize the nanostructured mesoporous silica (MS)/hydroxyapatite (HA) hybrid particles containing amphiphilic triblock copolymer. The controlled hydration layer structures on the hybrid particles significantly affected the protein secondary structures for providing the higher cytocompatibility.

Preparation of Pt Nanoparticles Dispersed in Mesoporous Silica

2009 ◽  
Vol 1217 ◽  
Author(s):  
Yukitoshi Chiba ◽  
Hirobumi Shibata ◽  
Daichi Nagata ◽  
Takahiro Gunji ◽  
Ryuji Tamura ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Platinum Nanoparticles ◽  
Triblock Copolymer ◽  
Sol Gel ◽  
Pt Nanoparticles ◽  
Chelating Agent ◽  
Pluronic P123 ◽  
Amphiphilic Triblock Copolymer ◽  
Sol Gel Process ◽  
Phenanthroline Complex

AbstractPlatinum nanoparticles were dispersed in mesopores of mesoporous silica using a sol-gel process with a composite template consisting of an amphiphilic triblock copolymer (Pluronic P123 or F127) and a Pt-organic complex, which was prepared with K2Pt(II)Cl4 as a Pt source and 1,10-phenanthroline as a chelating agent. The obtained Pt-1,10-phenanthroline complex did not dissolve in any of several solvents, e.g., hexane, benzene, toluene, THF, H2O, CH3OH, and C2H5OH. However, when the Pt-1,10-phenanthroline complex was reacted with ethylenediamine it dissolved in many solvents. Platinum nanoparticles dispersed in mesoporous silica were obtained using a sol-gel process with a complex template consisting of Pt-1,10-phenanthroline-ethylenediamine, and an amphiphilic triblock copolymer (Pluronic P123 or F127). A sample dried at 353 K was bright yellow. When it was subsequently heat-treated at 823 K, it turned light gray. This change indicates that Pt nanoparticles can be obtained by heat-treatment at high temperature, because, to generate Pt nanoparticles, the organics chelated to Pt ions must be removed. Measurements from small-angle x-ray scattering show that mesoporous silica obtained using a complex template has a much more highly ordered pore structure than that obtained using only an amphiphilic triblock copolymer. It has both large pores (above 8 nm) and a large surface area (about 290 m2/g). Furthermore, results of a TEM investigation showed that Pt nanoparticles were generated only in mesopores of mesoporous silica.

scholarly journals Protein secondary structures (α-helix and β-sheet) at a cellular level and protein fractions in relation to rumen degradation behaviours of protein: a new approach

2005 ◽  
Vol 94 (5) ◽  
pp. 655-665 ◽  
Author(s):  
Peiqiang Yu
Keyword(s):  
Nutritive Value ◽  
Secondary Structures ◽  
Cellular Level ◽  
Heat Processing ◽  
Molecular Chemistry ◽  
New Approach ◽  
Ftir Microspectroscopy ◽  
Protein Secondary Structures ◽  
Α Helix ◽  
Β Sheet

Studying the secondary structure of proteins leads to an understanding of the components that make up a whole protein, and such an understanding of the structure of the whole protein is often vital to understanding its digestive behaviour and nutritive value in animals. The main protein secondary structures are the α-helix and β-sheet. The percentage of these two structures in protein secondary structures influences protein nutritive value, quality and digestive behaviour. A high percentage of β-sheet structure may partly cause a low access to gastrointestinal digestive enzymes, which results in a low protein value. The objectives of the present study were to use advanced synchrotron-based Fourier transform IR (S-FTIR) microspectroscopy as a new approach to reveal the molecular chemistry of the protein secondary structures of feed tissues affected by heat-processing within intact tissue at a cellular level, and to quantify protein secondary structures using multicomponent peak modelling Gaussian and Lorentzian methods, in relation to protein digestive behaviours and nutritive value in the rumen, which was determined using the Cornell Net Carbohydrate Protein System. The synchrotron-based molecular chemistry research experiment was performed at the National Synchrotron Light Source at Brookhaven National Laboratory, US Department of Energy. The results showed that, with S-FTIR microspectroscopy, the molecular chemistry, ultrastructural chemical make-up and nutritive characteristics could be revealed at a high ultraspatial resolution (∼10 μm). S-FTIR microspectroscopy revealed that the secondary structure of protein differed between raw and roasted golden flaxseeds in terms of the percentages and ratio of α-helixes and β-sheets in the mid-IR range at the cellular level. By using multicomponent peak modelling, the results show that the roasting reduced (P<0·05) the percentage of α-helixes (from 47·1 % to 36·1 %: S-FTIR absorption intensity), increased the percentage of β-sheets (from 37·2 % to 49·8 %: S-FTIR absorption intensity) and reduced the α-helix to β-sheet ratio (from 0·3 to 0·7) in the golden flaxseeds, which indicated a negative effect of the roasting on protein values, utilisation and bioavailability. These results were proved by the Cornell Net Carbohydrate Protein System in situ animal trial, which also revealed that roasting increased the amount of protein bound to lignin, and well as of the Maillard reaction protein (both of which are poorly used by ruminants), and increased the level of indigestible and undegradable protein in ruminants. The present results demonstrate the potential of highly spatially resolved synchrotron-based infrared microspectroscopy to locate ‘pure’ protein in feed tissues, and reveal protein secondary structures and digestive behaviour, making a significant step forward in and an important contribution to protein nutritional research. Further study is needed to determine the sensitivities of protein secondary structures to various heat-processing conditions, and to quantify the relationship between protein secondary structures and the nutrient availability and digestive behaviour of various protein sources. Information from the present study arising from the synchrotron-based IR probing of the protein secondary structures of protein sources at the cellular level will be valuable as a guide to maintaining protein quality and predicting digestive behaviours.

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