Application Of Stereolithography Research Articles

New Materials and Methods for Hierarchically Structured Tissue Scaffolds

ABSTRACTThe overall goal of our work is to develop new methods and materials for the fabrication of hierarchically structured, three-dimensional (3D) tissue scaffolds. Conventional scaffolds commonly lack substantial mechanical strength, and there is difficulty in controlling porosity, pore distribution, and pore interconnectivity. Additionally, the chemical nature of these scaffolds is typically homogenous. The ability to chemically modify selected areas on a scaffold is one method to direct cell growth in deliberate patterns; which could aid in the engineering of complex, functioning tissues. The general aim of this work is to address these issues through the application of stereolithography (SL) to the fabrication of hierarchically structured scaffolds.In order to achieve this goal, photopolymerizable materials must be developed that are both compatible with cell growth and with SL processing. SL methods are designed to produce arbitrary control over the physical structure of the part. In addition to physical structure control, control over the local surface chemistry of the scaffold is also desired. This would permit the use of both physical and chemical cues to control cell behavior in a tissue engineering construct. Chemical control could be achieved in SL methods by using photopolymerizable materials that can also be selectively chemically modified during the SL part building process. This paper provides an update on our work directed at using combined photoradical initiated polymerization and photoacid generator based chemical modification of a polymeric scaffold via multi-wavelength SL to produce hierarchically structured scaffolds.

Clinical applications of stereolithography in ear surgery

Clinical applications of stereolithography in ear surgery

P044: Clinical Applications of Stereolithography in Ear Surgery

P044: Clinical Applications of Stereolithography in Ear Surgery

Application of stereolithography for scaffold fabrication for tissue engineered heart valves.

A crucial factor in tissue engineering of heart valves is the functional and physiologic scaffold design. In our current experiment, we describe a new fabrication technique for heart valve scaffolds, derived from x-ray computed tomography data linked to the rapid prototyping technique of stereolithography. To recreate the complex anatomic structure of a human pulmonary and aortic homograft, we have used stereolithographic models derived from x-ray computed tomography and specific software (CP, Aachen, Germany). These stereolithographic models were used to generate biocompatible and biodegradable heart valve scaffolds by a thermal processing technique. The scaffold forming polymer was a thermoplastic elastomer, a poly-4-hydroxybutyrate (P4HB) and a polyhydroxyoctanoate (PHOH) (Tepha, Inc., Cambridge, MA). We fabricated one human aortic root scaffold and one pulmonary heart valve scaffold. Analysis of the heart valve included functional testing in a pulsatile bioreactor under subphysiological and supraphysiological flow and pressure conditions. Using stereolithography, we were able to fabricate plastic models with accurate anatomy of a human valvular homograft. Moreover, we fabricated heart valve scaffolds with a physiologic valve design, which included the sinus of Valsalva, and that resembled our reconstructed aortic root and pulmonary valve. One advantage of P4HB and PHOH was the ability to mold a complete trileaflet heart valve scaffold from a stereolithographic model without the need for suturing. The heart valves were tested in a pulsatile bioreactor, and it was noted that the leaflets opened and closed synchronously under subphysiological and supraphysiological flow conditions. Our preliminary results suggest that the reproduction of complex anatomic structures by rapid prototyping techniques may be useful to fabricate custom made polymeric scaffolds for the tissue engineering of heart valves.

Clinical Applications of Stereolithography. Surgical Applications in the Field of Plastic Surgery.

Stereolithography is a new method of rapid prototyping that was simultaneously developed in the US and Japan. This technology is becoming popular and advancing rapidly. In 1991, our department began to investigate the clinical applications of stereolithography. Since then, a few clinical applicationshave been developed. In this report, we will describe the application of stereolithography technology in the field of plastic surgery and discuss the problems and future of this new technique.

Stereolithography: application to neurosurgery

Computer-aided design (CAD) and computer-aided manufacturing (CAM) by stereolithography are already being widely used in industry for the design and manufacture of new parts and have already shown accuracy in reproducing the desired model. The only shortcoming of this technique is that it can only make one model at a time, a "prototype." It cannot be used for mass production. It is precisely this property, namely making a prototype, that makes it so attractive in reconstructive surgery and implantation of prostheses, where each "part" has to be adapted to the unique anatomy of the patient. It was not until the early nineties that reports of the application of stereolithography to reconstructive surgery appeared in the literature, and even now they are scarce. However, it is a very promising technique, and we think that it is important for physicians to familiarize themselves with this concept.

Application of stereolithography to subperiosteal implant manufacture.

Subperiosteal implants are an accepted and proven technique with a good long-term outcome. Although a technique of computed tomography to computer-assisted machining became available to drop the number of surgeries to one for ascertainment of bone topography, the problem of accurate bone modeling remains an issue. The advent of stereolithography as a new tool for modeling anatomy for subperiosteal implants and the advances in computed tomography offer a higher degree of build accuracy and repeatability than available before.

The Application of stereolithography to the fabrication of accurate molecular models

The process of stereolithography, which automatically fabricates plastic models from designs created in certain computer-aided design programs, has been applied to the production of accurate plastic molecular models. Atomic coordinates obtained from quantum mechanical calculations and from neutron diffraction data were used to locate spheres in the I-DEAS CAD program with radii proportional to the appropriate van der Waals radii. The sterolithography apparatus was used to build the models using a photosensitive liquid resin, resulting in hard plastic models that accurately represent the computed or experimental input structures. Three examples are given to illustrate how the models can be used to interpret experimental structure-activity data for systems of biological importance or host-guest chemistry: (1) Interpretation of kinetic data for the formation of a stable blocking complex between amiloride analogs and the epithelial sodium channel, (2) interpretation of binding and neural activity data for the interaction of certain amino acids and their analogs at the l-alanine taste receptor of the channel catfish, and (3) interpretation of shape selectivity and rate acceleration in cyclodextrin catalysis using models of the neutron diffraction structure of β-cyclodextrin and of the transition state for the cleavage of phenyl acetate by the secondary hydroxyl oxygen of β-cyclodextrin.