World to Chip Sample Introduction

The effort to pursue a greater quality of life has given rise to an entire industry devoted to acquiring technology that produces accurate medical diagnoses in a shorter amount of time than is currently possible. The goal is a very small, self contained system that is available to doctors in offices and to medical personnel in field situations. This goal has nearly been realized through recent advances in micro and nano technologies that allow diagnostic systems to shrink to the size of a microchip. However, as systems shrink in size, smaller sample introduction methods are needed. This paper explores three different possibilities for introducing sample from the macro environment to that of a micro-chip in a Micro Total Analysis (mu-TAS), or Lab-on-Chip (LOC), scenario. In addition to the world-to-chip possibilities, this paper also explores methods to maximize the quantity of sample delivered to specific locations on the chip for processing, while minimizing the chip area. The use of a fixed displacement, solenoid activated micropump, is verified as one method of sample entry. Standard Luer Lock syringes were also used in conjunction with Luer to 1/8 NPT fittings. Finally Hamilton micro syringes were used with UpChurch fluidic interconnects. The chip layouts included several different angles of intersection between two channels, as well as the use of multiple, smaller channels. The three methods are judged on ease of consumer use, ease of manufacturing, and finally overall reliability of the method. Preliminary results indicate that the micropump solution is the easiest for consumer use, is reliable, but is difficult to implement. The Luer lock fittings also provide easy consumer use; however, reliable sealing in combination with the shear volume of the syringes hinder implementation. Finally the Hamilton micro syringes in conjunction with UpChurch fluidic interconnects is difficult for personnel in the field to implement, but offers a reliable and easily implement- ed method of sample introduction.