A programmable drug delivery system can control the release rate of a drug. It can minimize side effects while maximizing therapeutic effects. In this research, we investigated the feasibility of producing a programmable drug delivery system using 3D printing technology. A capsule with a micro-orifice and a drug-laden hydrogel was designed. The designed system was then fabricated by the printing process using polycaprolactone and hydrogel. The printed drug delivery system was immersed in PBS at 37°C and the number of molecules released was measured thorough colorimetric analysis. The effect of diameter and length of the micro-orifice and concentration of the hydrogel on drug release characteristics was then determined. The initial burst release rate was found to be increased with increasing orifice size. Increasing the length of the orifice linearly delayed the start time of drug release. At length of 600 μm and 1,200 μm, drug release was initiated after 36 h and 72 h for, respectively. When the concentration of hydrogel was increased, drug release rate tended to decrease. These results successfully confirmed that a drug delivery system with controlled release rate and initiation time could be manufactured using 3D printing technology.

Micro-machining of a brittle material such as glass, silicon, etc., is important in micro fabrication. Particularly, micro-abrasive jet machining (μ-AJM) has become a useful technique for micro-machining of such materials. The μ-AJM process is mainly based on the erosion of a mask which protects brittle substrate against high velocity of micro-particle. Therefore, fabrication of an adequate mask is very important. Generally, for the fabrication of a mask in the μ-AJM process, a photomask based on the semi-conductor fabrication process was used. In this research a rapid mask fabrication technology has been developed for the μ-AJM. By scanning the focused UV laser beam, a micro-mask pattern was fabricated directly without photolithography process and photomask. Two kinds of mask patterns were fabricated using SU-8 and photopolymer (Watershed 11110). Using fabricated mask patterns, abrasive-jet machining of Si wafer were conducted successfully.