ABSTRACT
The structural organization of natural liver is instrumental in the multifunctionality of hepatocytes, and mimicking these specific architectures in tissue-engineered scaffold plays an important role in the engineering of an implantable liver equivalent in vitro. To achieve this goal, we have developed a novel fabrication process to create chitosan-gelatin hybrid scaffolds with well-organized architectures and highly porous structures by combining rapid prototyping, microreplication and freeze-drying techniques. The scaffolds obtained not only have analogous configurations of portal vein, central vein, flow-channel network and hepatic chambers, but also have high (>90%) porosity, with the mean pore size of 100microm. Swelling and degradation studies showed that the scaffold has excellent properties of hydrophilicity and biodegradability. A hepatocyte culture experiment was conducted to evaluate the efficiency of the well-defined chitosan-gelatin scaffold in facilitating hepatocyte growth in the inner layer of the scaffold in vitro. Scanning electron microscopy and histological analysis showed that hepatocytes could form large colonies in the predefined hepatic chambers, and these cavities could the completely filled with hepatocytes during 7 day culture. Albumin secretion and urea synthesis further indicated that the well-organized scaffolds were more suitable for hepatocyte culture.
Subject(s)
Biocompatible Materials/chemistry , Cell Culture Techniques/instrumentation , Chitosan/chemistry , Gelatin/chemistry , Liver/metabolism , Tissue Engineering/methods , Animals , Biodegradation, Environmental , Cell Culture Techniques/methods , Cell Proliferation , Freeze Drying , Hepatocytes/cytology , Liver/pathology , Male , Porosity , Rats , Rats, Sprague-DawleyABSTRACT
A rotating perfusion bioreactor system has recently been developed in our laboratory to produce 3D dynamic culture condition, and the critical-sized scaffolds with interconnected microchennels were fabricated. Gas exchange occurs by semipermeable membrane covered on each side of bioreactor and gas-permeable peristaltic pump tube. Rotation and perfusion of culture media through large scaffolds enhance well mixing and mass transport of oxygen and nutrients in the bioreactor. Osteoblastic cells attached to microchennels are exposed to a low fluid flow-induced shear stress level. This bioreactor system overcomes several defects exited in static culture condition, improves the culture environment, facilitates osteoblast proliferation, differntiation, significant matrix production and mineralization, and the controllability of culture process is enhanced. Large scaffolds/osteoblast constructs were cultured in the bioreactor system for 14 days. Osteoblastic cells attached to microchannels of scaffolds were observed under scanning electron microscope (SEM). The results indicated that cells grew extensively in the microchennels of large scaffolds.
Subject(s)
Animals , Rabbits , Animals, Newborn , Bioreactors , Cell Culture Techniques , Methods , Cell Differentiation , Osteoblasts , Cell Biology , Skull , Cell Biology , Tissue Engineering , Methods , Tissue ScaffoldsABSTRACT
It is the critical technology for bone tissue engineering to fabricate scaffolds, especially to fabricate the internal microchannel of scaffolds. Utilizing stereolithography rapid prototyping indirect fabrication approach, suitable size microchannel structure scaffolds with orientation, branching, and interconnectivity under control was manufactured. Observation under light microscope showed that the arrange of microchannel size was 200-600 microm, the orientation and branching were accorded with designed structure, and all the microchannels were completely interconnected. Scaffolds seeded with osteoblast cells were put into 6-well plate and rotating 3D dynamic culture system which was developed in our lab. The morphology of osteoblasts and the development on the surface and internal microchannel of scaffolds were observed under scanning electron microscope (SEM). The results indicated that the dynamic culture permited an even distribution of cells across the surface of scaffolds, besides, a few cells grew into the lumen of microchannels.
Subject(s)
Animals , Rabbits , Bone Substitutes , Cell Culture Techniques , Methods , Cells, Cultured , Osteoblasts , Cell Biology , Surface Properties , Tissue EngineeringABSTRACT
Aiming at overcoming the limitations of the plaster-casting method in traditional prosthetic socket fabrication, the idea of reconstructing the 3D models for bones and skin of the residual limb is proposed. Given the two-dimensional obtained image through CT scanning, using image processing and reverse engineering techniques, the 3D solid model of the residual limb can be successfully reconstructed. The new approach can reproduce both the internal and the external structure of the residual limb. It can moreover avoid making a positive mould by the way of manual modifications. In addition to this, it can provide a scientific basis for the individualization of prosthetic socket design.
Subject(s)
Artificial Limbs , Imaging, Three-Dimensional/methods , Knee Joint/diagnostic imaging , Knee Prosthesis , Prosthesis Design/methods , Prosthesis Fitting/methods , Radiographic Image Interpretation, Computer-Assisted/methods , Computer Simulation , Computer-Aided Design , Equipment Failure Analysis/methods , Humans , Models, Biological , User-Computer InterfaceABSTRACT
@#Objective In the prosthetic socket design process, the high cost and radiation deficiency caused by CT scanning which is a routine way to obtain the cross section image of the residual limb remain problems. Ultrasonic measuring approach is proposed to gain the bones and skin contour of the residual limb. MethodsAn ultrasonic measuring device to get the multiple ultrasonic images of the residual limb was developed firstly, a compound algorithm to reconstruct the multiple images into 2D image was designed, and then the feature extraction on the bones and skin was made. Results Conclusion Comparing with the like-kind cross sectional scanning technique, the ultrasonic measuring method has the characteristic of no radiation and low cost.
ABSTRACT
@# Objective Due to the problem of individual matching, exclusivity and loose with pure mechanical fixation for artificial hemi-knee joints made by traditional method, a new manufacturing process based on rapid prototyping technique and custom-made concept is presented.MethodsRapid prototyping was processed to rapidly and accurately shape the prototype of an artificial implant almost with the same shape as the hemi-knee joint of the patient, and the process based on Titanium alloy centrifugal casting technology and biomaterial sintering molding technology was used to fabricate the artificial hemi-knee joint and bioactive proximal tibia artificial bone, respectively.Results and ConclusionThe custom-made knee joint prosthesis has been fabricated and put into clinical use successfully. In comparison with the traditional implants, this system can realize the well matching movement between the artificial hemi-knee joint and its opposite. Meanwhile,the design of functional holes and tibial nails realizes the combination of biological fixation with mechanical fixation for the artificial implant,and the use of bioactive artificial bone promotes bone growth and minimizes the exclusive reaction.
ABSTRACT
UNLABELLED: During the past few years, the combination of medical imaging and rapid manufacturing technique has proven to be a very important development. On the other hand, the conventional method has some drawbacks. For example, it takes longer time to complete an operation and it also presents some difficulty in matching the repaired contours. With advanced software and hardware, an image of an undamaged bone similar to that of the patient can be made from computerised tomography (CT); and a physical object constructed by the mirror-processed image data can be quickly fabricated with a high degree of fitting with the patient's bone. This paper presents a methodology for the design and fabrication of an individual titanium tray for the repair of mandible defects. Methods for the tray modeling using CAD system are presented: A 3D model of the bony defect is generated after the acquisition of helical CT data. An individual tray is designed using freeform surfaces geometries and fabricated by rapid prototyping (RP) technology. The results of tray filling with bone-grafting materials are then presented. RESULT: the tray is inserted into the patient mandible segment. The symmetry and reconstruction quality contour of the repaired mandible was satisfactory. Thus, the patient is able to eat normally. The bone-grafting material harvested from the anterior ilium was low. The clinical experience showed that rapid prototyping and reverse engineering software are effective methods of fabricating custom trays for mandibular reconstruction after bone loss due to a tumor.
Subject(s)
Biocompatible Materials , Mandible/chemistry , Mandibular Prosthesis Implantation/methods , Mandibular Prosthesis , Materials Testing , Titanium/chemistry , Adult , Bone Transplantation/methods , Humans , Image Processing, Computer-Assisted , Male , Models, Theoretical , Prosthesis Design , Software , Tomography, X-Ray ComputedABSTRACT
Objective: To enable an artificial mandible substitute to be mostly suitable for mandibular reconstructon in individual patients. Methods: Use rapid prototypinlg and surface imitating as the primary technology for individualized design and manufacturing of the artificial mandible substitute. Results: An individualized artificial mandible substitute was designed and prepared. Conclusion: Rapid prototyping is feasible in individualized bone substitute preparation.
