In vitro evaluation of marrow clot enrichment on microstructure decoration, cell delivery and proliferation of porous titanium scaffolds by selective laser melting three‐dimensional printing

Abstract

Titanium alloy is a clinically approved material for bone substitution. Although three-dimensional printing (3DP) fabrication technique can build up porous Ti scaffolds with the designed shape and microstructure, the biomechanical performance of 3DP Ti scaffolds still need to be improved to increase the reliability of osseointegration capacity. To address this issue, rabbit bone marrow clot (MC) is used to modify 3DP Ti scaffolds by stem cell delivery and microenvironment decoration inside the pores of these scaffolds. Moreover, 3DP Ti scaffolds were built up using selective laser melting, and 3DP MC-Ti scaffolds were constructed through the enrichment of MC with Ti scaffolds in vitro. Results demonstrated that the obtained 3DP Ti scaffolds in current study has an average modulus of elasticity (ME) at 1294.48 MPa with average yield strength of 33.154 MPa. For MC-Ti scaffolds, MC enrichment obstructs the pores of 3DP scaffolds due to the large amount of fibrin and erythrocytes and leads to a decrease in ratio of live cells at 1-week culture. Cell proliferation and osteogenic differentiation performance of MC-Ti scaffolds were promoted with porous recanalization in the later 3 weeks. After 2 weeks in vitro culture, fivefold of cell number in MC-Ti scaffolds were observed than bone marrow-derived mesenchymal stem cell-seeded Ti scaffolds. Compared to Ti scaffolds, fourfold of deoxyribonucleic acid content, type I collagen-α1, osteocalcin, and alkaline phosphatase expression in MC-Ti scaffolds were observed after 4 weeks in vitro culture. Results suggested that the combination with MC is a highly efficient method that improves the biological performance of Ti scaffolds. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2245-2253, 2018.

Advances in the Biology, Detection Techniques, and Clinical Applications of Circulating Tumor Cells

“…In microfluidic chips, the precise fabrication of shapes and microstructures in microchannels makes it possible to separate and enrich tumor cells on a size-by-size basis [62]. Erythrocytes have stronger deformability and smaller volume, thus can easily cross various microstructures [63]. Niciński et al proposed a new tool that uses microfluidic devices, photovoltaic (PV)-based SERS activity platform, and shell separation nanoparticles (shins) for simultaneous separation and unlabeled analysis of circulating tumor cells in blood samples.…”

Functionalization of 3D-printed titanium alloy orthopedic implants: a literature review

“…As it is difficult to seed pure cells, rabbit bone marrow clot, an easily obtained cell substitute with the ability to deliver stem cells and decorate the microenvironment, was used to modify 3DPTOIs. After two weeks of in vitro culture, a fivefold increase in cell number on the implant was observed in the marrow clot group compared with the pure stem cell group [73]. However, direct animal experimental evidence of the osteogenic effect of marrow clot is still lacking.…”

“…In addition to BMP, many other materials, including stromal cell -derived factor-1 alpha (SDF-1α), cells, marrow clot, chitosan and simvastatin (table 4), have been loaded into 3DPTOIs to improve long-term stability [71][72][73][74][75].…”

“…To sum up, BMP, SDF-1α, cells, marrow clot, chitosan and simvastatin can all be loaded into 3DPTOIs to promote long-term stability. However, only BMP, SDF-1α and simvastatin have been verified in animal experiments [70][71][72][73][74][75]. It should be noted, however, that many of the bone-promoting add-ons such as BMP, SDF-1α and simvastatin are not allowed to be used in cancer patients, especially those who have undergone bone tumor resection, because they may stimulate tumor recurrence and metastasis by stimulating angiogenesis [75][76][77].…”

“…Growth factors [70] Increasing angiogenesis, osteogenesis, osteoinduction and osseointegration Yes Yes SDF-1α [71] Recruiting stem cells and enhancing osseointegration Yes Yes Cells [3,72] Improving osteogenesis Yes No Marrow clot [73] Improving biological performance of the implant Yes No Chitosan [74] Improving the seeding efficiency and proliferation of osteoblasts Yes No Simvastatin [75] Improving angiogenesis, osseointegration and bone ingrowth Yes Yes the bone it will be beneficial not only to the healing of the bone defect but also to early functional exercise of the affected limb, greatly reducing the suffering of patients. Thus, implants that could be used to treat bone infection are in high demand.…”