The Use of Nanoscaled Fibers or Tubes to Improve Biocompatibility and Bioactivity of Biomedical Materials

Nanofibers and nanotubes have recently gained substantial interest for potential applications in tissue engineering due to their large ratio of surface area to volume and unique microstructure. It has been well proved that the mechanical property of matrix could be largely enhanced by the addition of nanoscaled fibers or tubes. At present, more and more researches have shown that the biocompatibility and bioactivity of biomedical materials could be improved by the addition of nanofibers or nanotubes. In this review, the efforts using nanofibers and nanotubes to improve biocompatibility and bioactivity of biomedical materials, including polymeric nanofibers/nanotubes, metallic nanofibers/nanotubes, and inorganic nanofibers/nanotubes, as well as their researches related, are demonstrated in sequence. Furthermore, the possible mechanism of improving biocompatibility and bioactivity of biomedical materials by nanofibers or nanotubes has been speculated to be that the specific protein absorption on the nanoscaled fibers or tubes plays important roles

Vascularization of Nanohydroxyapatite/Collagen/Poly(L-lactic acid) Composites by Implanting Intramuscularly In Vivo

It still remains a major challenge to repair large bone defects in the orthopaedic surgery. In previous studies, a nanohydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composite, similar to natural bone in both composition and structure, has been prepared. It could repair small sized bone defects, but they were restricted to repair a large defect due to the lack of oxygen and nutrition supply for cell survival without vascularization. The aim of the present study was to investigate whether nHAC/PLA composites could be vascularized in vivo. Composites were implanted intramuscularly in the groins of rabbits for 2, 6, or 10 weeks (n=5×3). After removing, the macroscopic results showed that there were lots of rich blood supply tissues embracing the composites, and the volumes of tissue were increasing as time goes on. In microscopic views, blood vessels and vascular sprouts could be observed, and microvessel density (MVD) of the composites trended to increase over time. It suggested that nHAC/PLA composites could be well vascularized by implanting in vivo. In the future, it would be possible to generate vascular pedicle bone substitutes with nHAC/PLA composites for grafting

Axial Vascularization of Nano-HA/Collagen/PLA Composites by Arteriovenous Bundle

In previous studies, nano-hydroxyapatite/collagen/poly(L-lactic acid) (nHAC/PLA) composites have been prepared and confirmed to repair small sized bone defects. However, they are restricted to repair a large defect without sufficient oxygen and nutrition for cell survival. The result of this study confirmed that nHAC/PLA composites could be axially vascularized by being implanted intramuscularly with arteriovenous (AV) bundle (Group A) in the groins of rabbits. The combination with autologous bone marrow (Group B) could not enhance it the vascularization in early phase (2 weeks, P>0.05), but it could enhance in middle and later phases (6 and 10 weeks, P<0.01). It meant that nHAC/PLA could be prefabricated as a vascularized bone substitute for grafting

Study on vertical mandibular distraction osteogenesis using magnesium alloy on canine

The bone formation feasibility by a novel magnesium alloy device was evaluated using a canine vertical mandibular distraction osteogenesis (DO) model. Osteotomies were performed in the area where last 3 star׳s teeth of left mandibular were pulled out before 3 months. Both AZ31 magnesium alloy (n=6) and 316L stainless steel (n=6) distraction devices were implanted. The distraction osteogenesis was carried out with a latency of 5 days after mandibular osteotomy. Distraction proceeded at a rate of 0.3 mm/8 h for 7 days and followed by 4 weeks of consolidations. The evaluations were conducted by scanning electron microscopy (SEM) and histological examinations. There were osteoblasts and trabecular bones formations manifestly in both groups. There was no significant difference in the bone mineral density between the two groups. The surface of the magnesium alloy was much more cracked and uneven, resulting from the surface pitting corrosion. The crew nails were closely combined with the surrounding bone tissue. AZ31 magnesium alloy exhibited a certain degradation rate in mandibular and did not post a negative effect on the kidney and liver. The observations in magnesium alloys group is consistent with the stainless steel group

In Vivo Osteogenesis of Vancomycin Loaded Nanohydroxyapatite/Collagen/Calcium Sulfate Composite for Treating Infectious Bone Defect Induced by Chronic Osteomyelitis

A novel antibacterial bone graft substitute was developed to repair bone defects and to inhibit related infections simultaneously. This bone composite was prepared by introducing vancomycin (VCM) to nanohydroxyapatite/collagen/calcium sulphate hemihydrate (nHAC/CSH). XRD, SEM, and CCK-8 tests were used to characterize the structure and morphology and to investigate the adhesion and proliferation of murine osteoblastic MC3T3-E1 cell on VCM/nHAC/CSH composite. The effectiveness in restoring infectious bone defects was evaluated in vivo using a rabbit model of chronic osteomyelitis. Our in vivo results implied that the VCM/nHAC/CSH composite performed well both in antibacterial ability and in bone regeneration. This novel bone graft substitute should be very promising for the treatment of bone defect-related infection in orthopedic surgeries

The effect of calcium phosphate microstructure on bone-related cells in vitro

Microstructure is essential for inductive bone formation in calcium phosphate materials after soft tissue implantation. We hereby evaluated activities (cell attachment, proliferation, ALP/DNA and protein/DNA) of three types of cells cultured on three kinds of calcium phosphate ceramic discs to study how microstructure takes its role in inductive bone formation. Three kinds of biphasic calcium phosphate (BCP) ceramic discs with the same chemistry and the same dimension of ∅10.0 × 1.0 mm3 (BCP1150-P, BCP1150-D and BCP1300), either having similar micropore sizes and surface roughness but different surface area (BCP1150-P vs BCP1150-D) or having similar surface area but different micropore sizes and different roughness (BCP1150-D vs BCP1300), were prepared. Conventionally Culturing C2C12, human bone marrow stromal cells (HBMSC) and MC3T3-E1 cells on BCP discs showed that, surface roughness did not affect cell attachment, cell proliferation and ALP expression of all cell types evaluated, while surface area did affect cell functions. ALP/DNA of C2C12 on BCP1150-P, having larger surface area, was significantly higher than on BCP1300 and BCP1150-D. Furthermore, all cells cultured on all of the three kinds of BCPs pre-soaked in culture medium having additional rhBMP-2 had a higher ALP expression than the conventional cell culture. Comparing with on BCP1300 and BCP1150-D, ALP/DNA of all cells tested increased more on BCP1150-P after the discs were pre-soaked in culture medium with rhBMP-2. The results indicated that increasing surface areas, microstructured calcium phosphate materials might concentrate more proteins (including bone-inducing proteins) that differentiate inducible cells to osteogenic cells that form inductive bone

3D-Printed Biopolymers for Tissue Engineering Application

3D printing technology has recently gained substantial interest for potential applications in tissue engineering due to the ability of making a three-dimensional object of virtually any shape from a digital model. 3D-printed biopolymers, which combine the 3D printing technology and biopolymers, have shown great potential in tissue engineering applications and are receiving significant attention, which has resulted in the development of numerous research programs regarding the material systems which are available for 3D printing. This review focuses on recent advances in the development of biopolymer materials, including natural biopolymer-based materials and synthetic biopolymer-based materials prepared using 3D printing technology, and some future challenges and applications of this technology are discussed

The use of nanoscaled fibers or tubes to improve biocompatibility and bioactivity of biomedical materials

Nanofibers and nanotubes have recently gained substantial interest for potential applications in tissue engineering due to their large ratio of surface area to volume and unique microstructure. It has been well proved that the mechanical property of matrix could be largely enhanced by the addition of nanoscaled fibers or tubes. At present, more and more researches have shown that the biocompatibility and bioactivity of biomedical materials could be improved by the addition of nanofibers or nanotubes. In this review, the efforts using nanofibers and nanotubes to improve biocompatibility and bioactivity of biomedical materials, including polymeric nanofibers/nanotubes, metallic nanofibers/nanotubes, and inorganic nanofibers/nanotubes, as well as their researches related, are demonstrated in sequence. Furthermore, the possible mechanism of improving biocompatibility and bioactivity of biomedical materials by nanofibers or nanotubes has been speculated to be that the specific protein absorption on the nanoscaled fibers or tubes plays important roles

A Novel Injectable Magnesium/Calcium Sulfate Hemihydrate Composite Cement for Bone Regeneration

Objective. A novel injectable magnesium/calcium sulfate hemihydrate (Mg/CSH) composite with improved properties was reported here. Methods. Composition, setting time, injectability, compressive strength, and bioactivity in simulated body fluid (SBF) of the Mg/CSH composite were evaluated. Furthermore, the cellular responses of canine bone marrow stromal cells (cBMSCs) and bone formation capacity after the implantation of Mg/CSH in tibia defects of canine were investigated. Results. Mg/CSH possessed a prolonged setting time and markedly improved injectability and mechanical property p<0.05. Mg/CSH samples showed better degradability than CSH in SBF after 21 days of soaking p<0.05. Moreover, the degrees of cell attachment, proliferation, and capability of osteogenic differentiation on the Mg/CSH specimens were higher than those on CSH, without significant cytotoxicity and with the increased proliferation index, ALP activity, and expression levels of integrin β1 and Coll I in cBMSCs p<0.05. Mg/CSH enhanced the efficiency of new bone formation at the tibia defect area, including the significantly elevated bone mineral density, bone area fraction, and Coll I expression level p<0.05. Conclusions. The results implied that this new injectable bone scaffold exhibited promising prospects for bone repair and had a great potential in bone tissue engineering