In this study HDPE specimens were fabricated by selective laser sintering using different particle sizes to obtain controlled variations in the porosity. Electron microscopy, density measurements and mechanical analyses were conducted for the characterization of the specimens. Parts with controlled pore gradients were also manufactured and characterized. The specimens with larger particle sizes had a high sintering degree and a significant level of close pores, as shown by microscopy and density analyses. However, the mechanical properties of specimens prepared with large particles had low values due to the limited density of union points, i.e., low neck number/area. HDPE parts with pore gradients were prepared by selective laser sintering demonstrating that this technique can be used to easily control the structure and the properties of the parts manufactured. This technology may have applications in areas such as drug delivery devices and scaffolds for tissue engineering
Drug delivery devices are systems employed to conduct a drug to a specific site of the body, where it should be released and absorbed. Reservoir-type systems are devices in which the drug is contained within a nucleus isolated from the outside environment by a thin polymeric layer, which regulates a diffusion process driven by a functional concentration gradient. In this study two reservoir-type drug delivery devices based on polycaprolactone (PCL) were developed for the release of progesterone (PG) using the Selective Laser Sintering (SLS) technique, in order to investigate the influence of the concentration gradient promoted during manufacturing on the drug delivery profile. Two types of controlled-drug-release devices were fabricated; the first containing only the polycaprolactone polymer in the reservoir wall (system R) and the second containing PLC and 15% of progesterone in the wall (system R*). The cores of both reservoirs were filled with 40 mg of progesterone. A study on the degradation was conducted to assess the release process of the two systems. The drug delivery results showed that for both reservoirs the amount of drug released was linear over time, featuring zero-order release kinetics. The higher mass loss with the incorporation of the drug into the wall of the reservoir was associated with faster release of the drug to the medium. The feasibility of building threedimensional parts using the SLS technique allowed the construction of reservoir-type devices based on a functional gradient for the controlled-release of the drug.
The techniques of Rapid Prototyping, also known as Additive Manufacturing, have prompted research into methods of manufacturing polymeric materials with controlled porosity. This paper presents the characterization of the structure and mechanical properties of porous polycaprolactone (PCL) fabricated by Selective Laser Sintering (SLS) using two different particle sizes and laser processing conditions. The results of this study indicated that it is possible to control the microstructure, that is, pore size and degree of porosity, of the polycaprolactone matrix using the SLS technique, by varying the particle size and laser energy density, obtaining materials suitable for different applications, scaffolds and drug delivery and fluid mechanical devices. The specimens manufactured with smaller particles and higher laser energy density showed a higher degree of sintering, flexural modulus, and fatigue resistance when compared with the other specimens.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.