Study On The Quantitative Visualization Method Of Three-dimensional Bio-printed Scaffolds

3D printing technology realizes the independent design of tissue engineering scaffolds and the precise and controllable spatial structure.Due to the deformation characteristics of printing materials and random errors in the printing process,however,the internal microstructure of the scaffold is inconsistent with the design.Meanwhile,the spatial structure and structural parameters of the scaffold also have a great influence on the analysis of its physical and chemical properties and cell activities.Therefore,the realization of characterization of scaffold structure parameters,such as pore size,strut size and spatial connectivity.It is crucial to the evaluation of scaffold characteristics and the control of scaffold printing process.Optical coherence tomography(OCT)has been widely used in the evaluation of tissue engineering scaffolds because it can realize the depth domain imaging with micron resolution.However,the imaging volume range of Optical Coherence Tomography(OCT)restrict the ability of its global quantitative characterization and visualization.Quantitative evaluation only local information from the scaffold significantly reduces the accuracy of quantitative characterization of global structure parameters and lack the ability visualization and quantitative analysis at different thickness of scaffold.Therefore,the visualization of OCT large-volume imaging is the premise and basis for accurate evaluation and analysis of the full-depth structure of printing scaffolds.Based on the above background,this project proposes a high-resolution lossless method based on Large volume optical coherence tomography(L-OCT)to obtain 3d printed scaffold structure images.In this project,OCT system is integrated into 3d printing equipment.3d printing and OCT are synchronized or alternately to complete sample printing and OCT data acquisition of different printing thicknesses.Image Mosaic technology and image fusion technology are used in OCT data processing to realize horizontal and vertical volume expansion.In order to verify the feasibility and accuracy,use hydrogel and polymer materials respectively to build 3D scaffold,design model size is 20mm(x)× 20mm(y)× 9mm(z)and 20mm(x)×20mm(y)× 4.95 mm(z)respectively,the imaging resolution is 15?m(x)× 15?m(y)× 2.25 ?m(z)and 15?m(x)× 15?m(y)× 2.57?m(z)respectively,a single OCT image acquisition time is 5.2 s.Based on the high-resolution imaging results of L-OCT,the thickness of each layer,pore size of different regions and the variation of strut size of the whole polymer scaffold were quantitatively analyzed.The research results show that based on L-OCT imaging has no-radiation,non-intrusive and low cell damage,not only implement visualization of OCT large-volume imaging but also can be combined with image processing and analysis for three dimensional printing support global structure information and quantitative analysis of the microstructure of the 3D printing process optimization and refinement of laid a foundation.