Jian-Chih Chen

Properties of osteoconductive biomaterials: Calcium phosphate cement with different ratios of platelet-rich plasma as identifiers

This study aims to evaluate further the performance of a platelet-rich plasma (PRP) additive incorporated with calcium phosphate bone cement (CPC) in vitro to prove its efficiency as bone graft substitutes and its compatibility to be incorporated into the CPC with other techniques in clinical restoration in vivo. The growth factor release ability and the osteogenic evaluation of PRP, CPC, and PRP/CPC testing groups with 5, 10, and 15 wt.% PRP were compared in vitro. Four groups were measured using non-decalcified staining methods in vivo, which include the testing group of 10 wt.% PRP/CPC selected from the evaluation in vitro, by using both the autograft with rabbit trabecular and CPC-only as comparison groups and the group without grafting material as the control sample. The results obtained through specimen immersion show that growth factor release and alkaline phosphatase activities after osteoprogenitor cell culture had a significantly better effect on 10 and 15 wt.% PRP/CPC than on the other groups in vitro. Analysis results suggest that PRP was still retained in the CPC matrix even after 32 days of immersion. The results in vivo show that the histology of the autograft bone and the control group without grafting material exhibited fibrous connective and adipose tissues, which obviously filled the created cavity even at nine weeks after the operation. Osteoregeneration was more successful in the PRP-additive group, which accumulated bone remodeling than in the other groups. In conclusion, CPC could be a potential carrier with adequate PRP additives that bear a therapeutic potential for enhanced bone tissue regeneration.

Calcium phosphate bone cement with 10 wt% platelet-rich plasma in vitro and in vivo.

OBJECTIVESnThe aim of this study was to evaluate the performance of a 10 wt% platelet-rich plasma (PRP) additive composite with calcium phosphate cement (CPC) in vitro and in vivo.nnnMETHODSnThe in vitro testing of modulus, the apatite conversion rate, morphology, cell and alkaline phosphatase (ALP) activities, and in vivo testing of histological examinations between two groups of 10 wt% PRP/CPC and CPC were characterised and compared.nnnRESULTSnAlthough the crystallite morphologies showed a retarded effect in the PRP/CPC group in vitro, the modulus results showed that the 10 wt% PRP/CPC group had a significant reduction in strength but had no significant changes in the relative conversion ratio of the apatite phase with CPC only. The osteogenic evaluation of ALP expression was significantly increased by the PRP additives group with stem cells (D1) cultured for different periods (2-32 days). Our histological examinations showed that greater remodelling and the phenomenon of isolated/detached CPC particles were significantly observed at 9 weeks after implantation when the 10 wt% PRP/CPC composite was used.nnnCONCLUSIONnThe results demonstrate that CPC may be a potential candidate as a carrier with PRP additives for bone regeneration.

Osteoregenerative capacities of dicalcium phosphate-rich calcium phosphate bone cement.

Calcium phosphate cement (CPC) is a widely used bone substitute. However, CPC application is limited by poor bioresorption, which is attributed to apatite, the stable product. This study aims to systematically survey the biological performance of dicalcium phosphate (DCP)-rich CPC. DCP-rich CPC exhibited a twofold, surface-modified DCP anhydrous (DCPA)-to-tetracalcium phosphate (TTCP) molar ratio, whereas conventional CPC (c-CPC) showed a onefold, surface unmodified DCPA-to-TTCP molar ratio. Cell adhesion, morphology, viability, and alkaline phosphatase (ALP) activity in the two CPCs were examined with bone cell progenitor D1 cultured in vitro. Microcomputed tomography and histological observation were conducted after CPC implantation in vivo to analyze the residual implant ratio and new bone formation rate. D1 cells cultured on DCP-rich CPC surfaces exhibited higher cell viability, ALP activity, and ALP quantity than c-CPC. Histological evaluation indicated that DCP-rich CPC showed lesser residual implant and higher new bone formation rate than c-CPC. Therefore, DCP-rich CPC can improve bioresorption. The newly developed DCP-rich CPC exhibited potential therapeutic applications for bone reconstruction.

Biphasic products of dicalcium phosphate-rich cement with injectability and nondispersibility

In this study, a calcium phosphate cement was developed using tetracalcium phosphate and surface-modified dicalcium phosphate anhydrous (DCPA). This developed injectable bone graft substitute can be molded to the shape of the bone cavity and set in situ through the piping system that has an adequate mechanical strength, non-dispersibility, and biocompatibility. The materials were based on the modified DCPA compositions of calcium phosphate cement (CPC), where the phase ratio of the surface-modified DCPA is higher than that of the conventional CPC for forming dicalcium phosphate (DCP)-rich cement. The composition and morphology of several calcium phosphate cement specimens during setting were analyzed via X-ray diffractometry and transmission electron microscopy coupled with an energy dispersive spectroscopy system. The compressive strength of DCP-rich CPCs was greater than 30MPa after 24h of immersion in vitro. The reaction of the CPCs produced steady final biphasic products of DCPs with apatite. The composites of calcium phosphate cements derived from tetracalcium phosphate mixed with surface-modified DCPA exhibited excellent mechanical properties, injectability, and interlocking forces between particles, and they also featured nondispersive behavior when immersed in a physiological solution.

Mineralization and osteoblast cells response of nanograde pearl powders

Themain objective of this study is to characterize the thermal, mineralization, and osteoblast cells response of pearl nanocrystallites. The results obtained from X-ray diffraction, FTIR spectra demonstrate that the pearl nano-crystallites can induce the formation of an HA layer on their surface in SBF, even after only short soaking periods. The in vitro cell response to nano-grade pearl powders is assessed by evaluating the cytotoxicity against a mouse embryonic fibroblast cell line and by characterizing the attachment ability and alkaline phosphatase activity of mouse bone cells (MC3T3-E1, abbreviated to E1) and bonemarrowstromal precursor (D1) cells. The cytotoxicities of pearls were tested by the filtration and culture of NIH-3T3 mouse embryonic fibroblast cells. The viability of the cultured cells in media containing pearl crystallites for 24 and 72 h is greater than 90%. Thebone cells seen in these micrographs are elongated and align predominately along the pearl specimen. The cells observed in these images also appeared well attached and cover the surface almost completely after 1 h. The pearl nanocrystallites had a positive effect on the osteogenic ability of ALP activity, and this promoted the osteogenic differentiation of MSCs significantly at explanations.

Modulating the release of proteins from a loaded carrier of alginate/gelatin porous spheres immersed in different solutions

BACKGROUNDnA biodegradable porous particle for the controlled biofactor delivery which assembly of pores in scaffolds can improve the permeation and diffusion of drugs or growth factors.nnnOBJECTIVEnPorous-spheres in millimeter scale were prepared by mixing sodium alginate and gelatin interpenetrating networks with cross-linkers; interconnected open pores were fabricated through solvent casting and particulate leaching.nnnMETHODSnMorphological characteristics, degradation, and bovine serum albumin (BSA) release rates of the porous-spheres immersed in three different solutions, namely, deionized distilled water, simulated body fluid (SBF), and phosphate-buffered saline (PBS), were detected.nnnRESULTSnPorous-spheres with a large amount of gelatin exhibited an increase in water absorption rates without affecting scaffold strength and no cytotoxicity was elicited. Highly interconnected pores with a diameter of 100-200xa0µm were uniformly distributed in scaffolds. The weight loss in PBS was faster than that in other solutions; the highest release rate of BSA in SBF was observed for 2xa0h. The release rates also exhibited linear patterns from 2xa0h to 24xa0h in all of the groups.nnnCONCLUSIONSnAfter 1 d of immersion in solutions, BSA release rates in scaffolds logarithmically decreased for 14 d. The degradation of porous-spheres also showed an inverse pattern.

A comparison of the heat treatment duration and the multilayered effects on the poly(lactic) acid braid reinforced calcium phosphate cements used as bone tissue engineering scaffold

Composites comprising a braided poly(lactic) acid (PLA) filament and calcium phosphate bone cement (CPC) were inferred to maintain space and to pack porous fillers into restorative sites. Composites of alkalized multilayer-PLA braids and CPC (PLA/CPC) were divided into various groups according to a series of heat-treatment periods that lasted for 60, 90, 120, 150, and 180u2009min at 160℃; subsequently, these composites were characterized. Strength decays of samples were also compared after 24u2009h immersion in Hanks’s physiological solution. Results showed that the PLA/CPC specimens were toughened after treatment at 160℃ for 120u2009min. Furthermore, the moduli of PLA/CPC groups increased significantly when the heating time was more than 150u2009min; this effect was generated by the cold crystallization within the PLA filaments. The reduced stress in the composites after immersion was attributed to the fibers that protruded from the scaffold surface and to hydrolysis. The mechanical test results for the PLA/CPC composites indicated that the toughening effect was strengthened significantly under prolonged heat treatment, especially when the heating time was longer than 150u2009min. The cold crystallization degree of PLA increased, thereby enhancing the strength and toughness of a specimen before immersion. Thus, PLA/CPC composites can be used to simulate potential bone functions as well as to maintain three-dimensional spaces and pack porous fillers into restorative sites conveniently.