Growth behavior, matrix production, and gene expression of human osteoblasts in defined cylindrical titanium channels

Abstract

The purpose of the current study was to investigate the effect of different diameters of cylindrical titanium channels on human osteoblasts. Titanium samples having continuous drill channels with diameters of 300, 400, 500, 600, and 1000 microm were put into osteoblast cell cultures that were isolated from 12 adult human trauma patients. Cell migration into the drill channels was investigated by transmitted-light microscopy. The DNA content in the drill channels was measured photometrically, collagen type I production was analyzed by enzyme-linked immunosorbent assay (ELISA) and osteocalcin gene expression by reverse transcriptase-polymerase chain reaction (RT-PCR). Formation of mineralized tissue was assessed by microradiographs of histological sections. Within 20 days, cells grew an average of 838 microm (+/-128 microm) into the drill channels with a diameter of 600 microm and were significantly faster (p < 0.05) than in all other channels. Cells produced significantly more osteocalcin messenger RNA (mRNA) in 600-microm channels (p < 0.05) than they did in 1000-microm channels and demonstrated the highest osteogenic differentiation. The channel diameter did not influence collagen type I production. The highest cell density was found in 300-microm channels (p < 0.05). The DNA content of the channels linearly decreased with increasing channel diameters. After 40 days of culture, the proportion of mineralized tissue at the mouth section amounted to 6% in 300-microm channels and to 9-11% in 400-600-microm channels. In 1000-microm channels, only traces of mineralization were detected. Our data suggest that the diameter of cylindrical titanium channels has a significant effect on migration, gene expression, and mineralization of human osteoblasts.

Bulk and porous metastable beta Ti–Nb–Zr(Ta) alloys for biomedical applications

“…[26][27][28]37] with that of Ti-Nb-Zr foam: the apparent Young's modulus matches perfectly that of the bone, but the CS ⁎ is always higher, being about 70 MPa for the high-porosity samples of our study. One of the important characteristics of materials for orthopedic applications is the maximum elastic strain: for bone it is about 1.1%, for the high-porosity Ti-Nb-Z rs p e c i m e n si ti sa r o u n d3 % ,w h i c h guarantees that the implant will not be damaged before the bone [26][27][28]37]. …”

“…The graphed pore size distributions (Fig. 9d,e,f) [26][27][28]. The lower pore size limit is related to the size of cells (~50 μm), while the upper pore size limit is related to the availability of binding sites and the anatomic dimensions of the pores of the specific bone tissue to be replaced.…”

Porous Titanium‐6 Aluminum‐4 Vanadium Cage Has Better Osseointegration and Less Micromotion Than a Poly‐Ether‐Ether‐Ketone Cage in Sheep Vertebral Fusion

“…Moreover, osteogenic differentiation potential of cells and the degree of matrix mineralization were also found to be better with larger pores (43). One possible explanation is that large pores would encourage faster nutrient and gas exchange, with less accumulation of metabolic waste in the central part of the scaffold (43). In addition, Kujala et al also reported that porous scaffolds with larger pores (505 ± 136 μm) had less fibrosis within the implant than scaffolds with smaller pores (259 ± 30 μm) (44).…”

“…Although it has been suggested that a wide range of pore sizes from 150-1000 μm allow bone ingrowth (41-43), Frosch et al found that large pores (600 μm) may allow much deeper and faster osteoblast ingrowth than small pores (300-500 μm). Moreover, osteogenic differentiation potential of cells and the degree of matrix mineralization were also found to be better with larger pores (43). One possible explanation is that large pores would encourage faster nutrient and gas exchange, with less accumulation of metabolic waste in the central part of the scaffold (43).…”

The influence of direct laser metal sintering implants on the early stages of osseointegration in diabetic mini-pigs

“…29 Previous studies found that bones prefer to grow in pores depth of 100-400 µm. 30 Mangano et al 31 investigated the biological response of direct metal laser sintering implant surfaces in vitro.…”