Problems: Tissue engineering (TE) is one of the modern strategies to provide a functional biological tissue equivalent to restore or improve the function of human tissues that lost by disease, traumatic events, or congenital abnormalities. Some essential factors in TE are tissue type and appropriate scaffold. suitable influence on cell viability and proliferation is One of the most important characteristics of a appropriate scaffold for tissue engineering. The purpose of this research was to comparative evaluation of adipose derived stem cells (ADSCs) proliferation rate and their viability on the five different scaffolds. Experimental approach: six different scaffolds were prepared including Alginate, Poly Lactic Glycolic Acid (PLGA), Fibrin glue (FG), Inactive Platelet- Rich Plasma (IPRP), Active Platelet- Rich Plasma (APRP) and Hydroxyapatite/ β

The Design of Scaffolds for Use in Tissue Engineering

Bone is the most implanted tissue after blood. The major solid components of human bone are collagen (a natural polymer, also found in skin and tendons) and a substituted hydroxyapatite (a natural ceramic, also found in teeth). Although these two components when used separately provide a relatively successful mean of augmenting bone growth, the composite of the two natural materials exceeds this success. This paper provides a review of the most common routes to the fabrication of collagen (Col) and hydroxyapatite (HA) composites for bone analogues. The regeneration of diseased or fractured bones is the challenge faced by current technologies in tissue engineering. Hydroxyapatite and collagen composites (Col-HA) have the potential in mimicking and replacing skeletal bones. Both in vivo and in vitro studies show the importance of collagen type, mineralisation conditions, porosity, manufacturing conditions and crosslinking. The results outlined on mechanical properties, cell culturing and de-novo bone growth of these devices relate to the efficiency of these to be used as future bone implants. Solid free form fabrication where a mould can be built up layer by layer, providing shape and internal vascularisation may provide an improved method of creating composite structures.

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Collagen-hydroxyapatite composites for hard tissue repair.

In vivo behavior of three different injectable hydraulic calcium phosphate cements.

Functionally graded electrospun polycaprolactone and beta-tricalcium phosphate nanocomposites for tissue engineering applications.

Effects of hydroxyapatite in 3-D chitosan-gelatin polymer network on human mesenchymal stem cell construct development.

With advances in ceramics technology, calcium phosphate bioceramics have been applied as bone substitutes for several decades. The focus of this work is to elucidate the biocompatibility of the particulates of various calcium phosphate cytotoxicities. Four different kinds of calcium phosphate powders, including beta-tricalcium phosphate (beta-TCP), hydroxyapatite (HA), beta-dicalcium pyrophosphate (beta-DCP), and sintered beta-dicalcium pyrophosphate (SDCP), were tested by osteoblast cell culture. The results were analyzed by cell count, concentration of transforming growth factor-beta 1 (TGF-beta 1), alkaline phosphatase (ALP), and prostaglandin E2 (PGE2) in culture media. The changes were most significant when osteoblasts were cultured with beta-TCP and HA bioceramics. The changes in cell population of the beta-TCP and HA were quite low in the first 3 days, then increased gradually toward the seventh day. The changes in TGF-beta 1 concentration in culture medium inversely related to the changes in cell population. The ALP titer in the culture media of the beta-TCP and HA were quite high in the first 3 days, then decreased rapidly between the third and seventh days. The concentrations of PGE2 in the culture media tested were quite high on the first day, decreased rapidly to the third day, and then gradually until the seventh day. The changes in the beta-DCP and SDCP were quite similar to those of HA and beta-TCP but much less significant. We conclude that HA and beta-TCP have an inhibitory effect on the growth of osteoblasts. The inhibitins effects of the HA and beta-TCP powders on the osteoblast cell cultures possibly are mediated by the increased synthesis of PGE2.

The effects of calcium phosphate particles on the growth of osteoblasts

Autogenous bone grafting is still the gold standard for use in bone defects in orthopedic, plastic, and craniofacial surgeries. However, some patients are unable to provide sufficient quantity of bone and the high postoperative morbidity limits its clinical use. Currently, various bone substitutes are available for clinical applications, including calcium phosphate and biodegradable polyester. But hydroxyapatite is considered nondegradable and the degradation rate of biodegradable polyester is too fast, therefore both these biomaterials are hardly used clinically. To resolve this problem, we fabricated a biodegradable porous bone substitute by merging poly(L-lactic-co-glycolic acid) (PLGA) and β-tricalcium phosphate (TCP), such that the new bone substitute could provide the advantages of both the materials. The New Zealand white rabbit femur defect model was used to assess the biocompatibility and degree of osteoconduction of this new bone substitute. There was no inflammatory reaction at the PLGA/TCP grafting site based on our macroscopic observations. Three months after grafting, the cavity and central portion of the created defect within the rabbit femur was filled with newly formed bone. Furthermore, the new ingrown bone tissues readily matured to secondary bone with Haversian systems similar to the surrounding cancellous bone. We conclude that the newly fabricated PLGA/TCP shows both excellent biocompatibility and effective osteoconduction.

Chun J. Liao

Papers

The effects of calcium phosphate particles on the growth of osteoblasts

The use of poly(l-lactic-co-glycolic acid)/tricalcium phosphate as a bone substitute in rabbit femur defects model

The effects of calcium phosphate particles on the growth of osteoblasts