Light cannot be propagated within the range of photonic crystal band gaps. Based on this unique property, we proposed a method to improve anti-radiation capability through one-dimensional photonic crystal coating. Using transmission matrix method, we determined the appropriate dielectric materials, thickness and periodic numbers of photonic crystals through Matlab programming simulation. Then, compound one-dimensional photonic crystal coating was designed which was of high anti-radiation rate within the range of X-ray. As is shown through simulation experiments, the reflection rate against X-ray was higher than 90 percent, and the desired anti-radiation effect was achieved. Thus, this method is able to help solve the technical problems facing the inorganic lead glass such as thickness, weightiness, costliness, high lead equivalent, low transparency and high cost. This method has won China's national invention patent approval, and the patent number is 201220228549.2.
Collagen (Coll), as the basic material of matrix scaffolds for cell growth, has been widely used in the field of tissue engineering and regenerative medicine. In this study, collagen protein was modified by L-lysine (Lys), and cross-linked by genipin (GN) to prepare the L-lysine-modified collagen (Lys-Coll-GN) scaffolds. Microstructure, pore size, porosity, stability and biocompatibility of Lys-Coll-GN scaffolds were observed. The results showed that the bond between L-lysine and collagen protein molecule was formed by generating amide linkage, and mouse embryo fibroblasts proliferation was not inhibited in the Lys-Coll-GN scaffolds. In the multiple comparisons of Coll-scaffolds, Coll-GNscaffolds and Lys-Coll-GN-scaffolds, Coll-scaffolds was the worst in mechanical characteristics while the highest in biodegradation rate. Compared to Coll-GN scaffolds, Lys-Coll-GN scaffolds had more fiber structure, higher interval porosity (P<0.01). Although the tensile stress of Lys-Coll-GN scaffolds reduced significantly, its elongation length extended when the scaffolds was fractured (P<0.01). The percentage of Lys-Coll-GN scaffolds residual weight was lower than that of Coll-GN-scaffolds after all the scaffolds were treated by collagenase for 5 days (P<0.01).This study suggested that Lys-Coll-GN scaffold had good biocompatibility, and it improved the mechanical property and degradation velocity for collagen-based scaffold. This study gave a new predominant type of tissue engineering scaffold for the regenerative medicine.
ObjectiveTo assess the role and effect of Wharton's jelly of human umbilical cord oriented scaffold on chondrocytes co-cultured in vitro. MethodsChondrocytes from shoulder cartilage of adult New Zealand rabbits were isolated,cultured,amplified,and labelled using fluorescent dye PKH26.Cells were extracted from human umbilical cord tissue using wet-grinding chemical technology to prepare the Wharton's jelly of human umbilical cord oriented scaffold by freeze-drying and cross-linking technology.Second generation of chondrocytes were cultured with Wharton's jelly of human umbilical cord oriented scaffold.Inverted microscope and scanning electron microscope (SEM) were used to observe the cell distribution and adhesion on the scaffold; extracellular matrix secretion of the chondrocytes were observed by toluidine blue and safranin O staining.Cells distribution and proliferation on the scaffold were assessed by fluorescein diacetate-propidium iodide (FDA-PI) and Hoechst33258 staining.The viability of the in vitro cultured and PKH26 fluorescence labelled chondrocytes on the scaffold were assessed via fluorescence microscope. ResultsInverted microscope showed that the cells cultured on the scaffold for 3 days were round or oval shaped and evenly distributed into space of the scaffold.SEM observation showed that large number of cultured cells adhered to the pores between the scaffolds and were round or oval shape,which aggregated,proliferated,and arranged vertically on longitudinally oriented scaffold at 7 days after culture.Histological observation showed that cells distributed and proliferated on the scaffold,and secreted large amount of extracellular matrix at 7 days.Scaffold could guide cell migration and proliferation,and could effectively preserve and promote the secretion of extracellular matrix.Cell viability assessments at 3 days after culture showed most of the adhered cells were living and the viability was more than 90%.PKH26 labelled chondrocytes were seen,which distributed uniformly along the pore of oriented scaffold,and exuberantly proliferated. ConclusionWharton's jelly of human umbilical cord oriented scaffold favors adhesion,proliferation,and survival of chondrocytes.It possesses a favorable affinity and cell compatibility.Thus,it is an ideal scaffold for cartilage tissue engineering.