Effect of polyaspartic acid on hydroxyapatite deposition in silk fibroin blend films

Abstract

Abstract. Polyaspartic acid/silk fibroin/hydroxyapatite (PASP/SF-HA) composites have been synthesized by biomimetic processing. SF solution was mixed with different contents of PASP to prepare the PASP/SF blend membranes. After ethanol treatment and premineralization process, the blend membranes were immersed into 1.5 simulated body fluid (1.5 SBF) for 24 h to induce apatite deposition at 37±0.5°C. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results revealed that a conformation transition of SF occurred after the addition of PASP and ethanol treatment. The FTIR and XRD results also confirmed that the main component of apatite deposition was HA. Scanning electron microscopy (SEM) showed that the content of HA increased with increasing PASP concentration .Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP) results revealed that the Ca/P molar ratio could reach 1.45, which was close to the Ca/P ratio of apatite. It was appropriate to conclude that the increasing content of PASP had a distinct effect on HA deposition in the blend films.

Morphology and thermal stability of silk fibroin/starch blended microparticles

“…However, the applications of SF films are limited due to their being very brittle in the dry state. The poor mechanical properties of the SF film could be improved by blending it with other polymers [7,8,9]. Other properties, such as conformational transition and thermal properties are dependant on the blended ratios.…”

Mineralization of calcium phosphate induced by a silk fibroin film under different biological conditions

“…2A), which can be attributed to the amide I, amide II and amide III bands of silk broin, respectively. 5,25,26 The similar positions of these peaks suggest that the secondary structure of silk broin did not change aer mineralization. In addition, the spectrum of the MSF shows two prominent bands at 563 cm À1 and 1058 cm À1 , which corresponds to the v 3 and v 4 vibrations of phosphate, respectively.…”

Polyaspartic Acid Concentration Controls the Rate of Calcium Phosphate Nanorod Formation in High Concentration Systems

“…Spectra were collected every 5 min. The ATR-FTIR spectra show peaks between 1750 and 1300 cm –1 assigned to pAsp, generally the amide modes, and peaks between 1150 and 950 cm –1 assigned to phosphate. − The spectral information associated with phosphate can be used to classify atomic ordering of the CaP phase. Crystalline phases and disordered phases can be easily differentiated. − To identify apatite, multiple reports have reported the ν 3 PO 4 3– antisymmetric stretch in the 1030 to 1033 cm –1 range. ,, In octacalcium phosphate (OCP), ν 3 PO 4 3– antisymmetric stretch occurs at slightly lower wavenumbers (1021–1028 cm –1 ). ,, Results on amorphous calcium phosphate (ACP) are more varied; however, a broad peak has been observed at 1052 cm –1 but can shift up to 1085 cm –1 , depending on the phosphate speciation (HPO 4 2– or PO 4 3– ). , Solution H 2 PO 4 – and HPO 4 2– peaks have also been reported at 1077 and 1080 cm –1 , respectively. , In our analysis, the peaks at 1024 and 1032 cm –1 were considered ordered peaks, whereas the broad peak centered at 1076 cm –1 was considered disordered; this broad peak likely contained contributions from the H 2 PO 4 – and HPO 4 2– in solution and in ACP.…”

“…Spectra were collected every 5 min. The ATR-FTIR spectra show peaks between 1750 and 1300 cm −1 assigned to pAsp, generally the amide modes, 18 and peaks between 1150 and 950 cm −1 assigned to phosphate. 19−22 The spectral information associated with phosphate can be used to classify atomic ordering of the CaP phase.…”