In vitro and in vivo degradation behavior of n‐HA/PCL‐Pluronic‐PCL polyurethane composites

Abstract

Scaffolds for bone tissue engineering applications should have suitable degradability in favor of new bone ingrowth after implantation into bone defects. In this study, degradation behavior of polyurethane composites composed of triblock copolymer poly(caprolactone)-poluronic-poly(caprolactone) (PCL-Pluronic-PCL, PCFC) and nanohydroxyapatite (n-HA) was investigated. The water contact angle and water absorption were measured to reveal the effect of n-HA content on the surface wettability and swelling behavior of the n-HA/PCFC composites, respectively. The weight loss in three degradation media with pH value of 4.0, 7.4, and 9.18 was also studied accordingly. Fourier transform infrared analysis, differential scanning calorimeter, X-ray diffraction, thermal-gravimetric analysis, and scanning electron microscopy were used to investigate the change of chemical structure and micromorphology after the n-HA/PCFC composite with 30% HA was degraded for different time intervals. Meanwhile, in vivo degradation was conducted by subcutaneous implantation. The weight loss and morphology change during observation periods were also studied.

The study of the structure and bioactivity of the B2O3 • Na2O • P2O5 system

“…One should also mention that the Raman band located at 877 cm À1 , characteristic to crystalline B(OH) 3 , could not be identified in our spectra. [37] This further supports the assumption that these crystallites are present only on the samples surface.…”

“…This type of morphology is characteristic for materials with boron content. [3,4] In Fig. 6(d), the EDAX spectra of the 30B 2 O 3 • 30Na 2 O • 40P 2 O 5 sample surface is illustrated.…”

“…Namely, the difficulty of processing it into porous 3D scaffolds and its slow and incomplete conversion to apatite when placed in body fluids. [2][3][4] To overcome these limitations, various materials with different chemical compositions were studied and published in the literature. Among these, the borate [4][5][6][7][8][9][10] and borophosphate [11][12][13][14][15][16][17][18][19][20][21][22] glasses have received a special attention.…”

“…On the other hand, phosphate bioactive glasses have been also under study due to their chemical resemblance to the bone structure. [3,9,11,25,26] These studies revealed that they undergo surface reactions once immersed in body fluids leading to the formation of an apatitelike layer and, consequently, to the ability of bonding to living tissue. However, it is known that in order to prepare this type of glasses, high temperatures are required, and they often have the tendency to crystallize.…”

Thermal and mechanical properties of nanocomposites based on a PLLA‐b‐PEO‐b‐PLLA triblock copolymer and nanohydroxyapatite

“…The hydrophilic nature of a PEO block improves the adhesion of the PLLA with synthetic ceramic materials based on calcium phosphates, such as nanohydroxyapatite (nHAp, Ca 10 (PO 4 ) 6 (OH) 2 ) and beta‐tricalcium phosphates (β‐TCP) . These inorganic particles have been applied as dispersed phases in polymeric biocomposites due to their similarity to the mineral phase of bone in terms of composition and bioactivity …”