Objective To compare product standards of drug and medical device made from sodium alginate and calcium alginate between domestic and abroad, and to emphases on the process parameters monitoring based on different standards. Methods Sodium alginate and calcium alginate standards of both domestic and foreign were analyzed and summarized, and the differences and commonalities of various product standards among each standard were compared. Results Differences exist in product standards of sodium alginate and calcium alginate between domestic and abroad, whether drug or medical device, but the fundamental control points are concordant. Conclusion Companies should focus on product quality control requirements combined with its own unique manufacturing process characteristics to develop reasonable and controllable quality standards, which can ensure safe and effective clinical use.
Objective To explore the effect of tissue engineered cartilage reconstructed by using sodium alginate hydrogel and SIS complex as scaffold material and chondrocyte as seed cell on the repair of full-thickness articular cartilage defects. Methods SIS was prepared by custom-made machine and detergent-enzyme treatment. Full-thickness articularcartilage of loading surface of the humeral head and the femoral condyle obtained from 8 New Zealand white rabbits (2-3weeks old) was used to culture chondrocytes in vitro. Rabbit chondrocytes at passage 4 cultured by conventional multipl ication method were diluted by sodium alginate to (5-7) × 107 cells/mL, and then were coated on SIS to prepare chondrocyte-sodium alginate hydrogel-SIS complex. Forty 6-month-old clean grade New Zealand white rabbits weighing 3.0-3.5 kg were randomized into two groups according to different operative methods (n=20 rabbits per group), and full-thickness cartilage defect model of the unilateral knee joint (right or left) was establ ished in every rabbit. In experimental group, the complex was implanted into the defect layer by layer to construct tissue engineered cartilage, and SIS membrane was coated on the surface to fill the defect completely. While in control group, the cartilage defect was filled by sodium alginate hydrogel and was sutured after being coated with SIS membrane without seeding of chondrocyte. General condition of the rabbits after operation was observed. The rabbits in two groups were killed 1, 3, 5, 7, and 9 months after operation, and underwent gross and histology observation. Results Eight rabbits were excluded due to anesthesia death, wound infection and diarrhea death. Sixteen rabbits per group were included in the experiment, and 3, 3, 3, 3, and 4 rabbits from each group were randomly selected and killed 1, 3, 5, 7, and 9 months after operation, respectively. Gross observation and histology Masson trichrome staining: in the experimental group, SIS on the surface of the implant was fused with the host tissue, and the inferface between them disappeared 1 month after operation; part of the implant was chondrified and the interface between the implant and the host tissue was fused 3 months after operation; the implant turned into fibrocartilage 5 months after operation; fiber arrangement of the cartilage in theimplant was close to that of the host tissue 7 months after operation; cartilage fiber in the implant arranged disorderly andactive cell metabol ism and prol iferation were evident 9 months after operation. While in the control group, no repair of thedefect was observed 9 months after operation. No obvious repair was evident in the defects of the control group within 9months after operation. Histomorphometric evaluation demonstrated that the staining intensity per unit area of the reparative tissue in the defect of the experimental group was significant higher than that of the control group at each time point (P lt; 0.05), the chondrification in the experimental group was increased gradually within 3, 5, and 7 months after operation (P lt; 0.05), and it was decreased 9 months after operation comparing with the value at 7 months after operation (P lt; 0.05). Conclusion Constructed by chondrocyte-sodium alginate hydrogel-SIS in complex with surficial suturing of SIS membrane, the tissue engineered cartilage can in-situ repair cartilage defect, promote the regeneration of cartilage tissue, and is in l ine with physiological repair process of articular cartilage.
【Abstract】 Objective To produce a new bone tissue engineered carrier through combination of xenograft bone (X)and sodium alginate (A) and to investigate the biological character of the cells in the carrier and the abil ity of bone-forming in vivo, so as to provide experimental evidence for a more effective carrier. Methods BMSCs were extracted from 2-week-old New Zealand rabbits and the BMSCs were induced by rhBMP-2 (1 × 10-8mol/L). The second generation of the induced BMSCs was combined with 1% (V/W) A by final concentration of 1 × 105/mL. After 4-day culture, cells in gel were investigated by HE staining. The second generation of the induced BMSCs was divided into the DMEM gel group and the DMEM containing 1% A group. They were seeded into 48 well-cultivated cell clusters by final concentration of 1 × 105/mL. Seven days later, the BMP-2 expressions of BMSCs in A and in commonly-cultivated cells were compared. The second generation of the induced BMSCs was mixed with 2% A DMEM at a final concentration of 1 × 1010/mL. Then it was compounded with the no antigen X under negativepressure. After 4 days, cells growth was observed under SEM. Twenty-four nude mice were randomly divided into 2 group s (n=12).The compound of BMSCs-A-X (experimental group) and BMSCs-X (control group) with BMSCs whose final concentrat ion was 1 × 1010/mL was implanted in muscles of nude mice. Bone formation of the compound was histologically evaluated by Image Analysis System 2 and 4 weeks after the operation, respectively. Results Cells suspended in A and grew plump. Cell division and nuclear fission were found. Under the microscope, normal prol iferation, many forming processes, larger nucleus, clear nucleolus and more nuclear fission could be seen. BMP-2 expression in the DMEM gel group was 44.10% ± 3.02% and in the DMEM containing 1% A group was 42.40% ± 4.83%. There was no statistically significant difference between the two groups (P gt; 0.05). A was compounded evenly in the micropore of X and cells suspended in A 3-dimensionally with matrix secretion. At 2 weeks after the implantation, according to Image Analysis System, the compound of BMSCs-A-X was 5.26% ± 0.24% of the totalarea and the cartilage-l ike tissue was 7.31% ± 0.32% in the experimental group; the compound of BMSCs-X was 2.16% ± 0.22% of the total area and the cartilage-l ike tissue was 2.31% ± 0.21% in the control group. There was statistically significant difference between the two groups (P lt; 0.05). At 4 weeks after the operation, the compound of BMSCs-A-X was 7.26% ± 0.26% of the total area and the cartilage-l ike tissue was 9.31% ± 0.31% in the experimental group; the compound of BMSCs-X was 2.26% ± 0.28% of the total area and the cartilage-l ike tissue was 3.31% ± 0.26% in the control group. There was statistically significant difference between the two groups (P lt; 0.05). Conclusion The new carrier compounding A and no antigen X conforms to the superstructural principle of tissue engineering, with maximum cells load. BMSCs behave well in the compound carrier with efficient bone formation in vivo.
Sodium alginate (SA) is a kind of natural polymer material extracted from kelp, which has excellent biocompatibility, non-toxicity, biodegradability and abundant storage capacity. The formation condition of sodium alginate gel is mild, effectively avoiding the inactivation of active substances. After a variety of preparation methods, sodium alginate microspheres are widely used in the fields of biomaterials and tissue engineering. This paper reviewed the common methods of preparing alginate microspheres, including extrusion, emulsification, electrostatic spraying, spray drying and coaxial airflow, and discussed their applications in biomedical fields such as bone repair, hemostasis and drug delivery.