In-Plane Biocompatible Microfluidic Interconnects for Implantable Microsystems

Abstract

Small mammals, particularly mice, are very useful animal models for biomedical research. Extremely small anatomical dimensions, however, make design of implantable microsystems quite challenging. A method for coupling external fluidic systems to microfluidic channels via in-plane interconnects is presented. Capillary tubing is inserted into channels etched in the surface of a Si wafer with a seal created by Parylene-C deposition. Prediction of Parylene-C deposition into tapered channels based on Knudsen diffusion and deposition characterizations allows for design optimization. Low-volume interconnects using biocompatible, chemical resistant materials have been demonstrated and shown to withstand pressure as high as 827 kPa (120 psi) with an average pull test strength of 2.9 N. Each interconnect consumes less than 0.018 mm3 (18 nL) of volume. The low added volume makes this an ideal interconnect technology for medical applications where implant volume is critical.

Age-related hearing loss: prevention of threshold declines, cell loss and apoptosis in spiral ganglion neurons

“…Translationally, it may be that ALD combined with other critical compounds could be given systemically (orally, time-release skin patch), if there are no side effects, or have beneficial systemic effects for an aging mammal. Alternatively, if side effects are detrimental (which was not the case in the current study, e.g., stable blood pressure throughout the treatment period), a medicine to improve hearing in the elderly could be given locally to the inner ear via microsystem delivery techniques that we are currently developing [ 79 - 82 ], or via transtympanic injections into the middle ear near the round window, perhaps using nanoparticles as drug carrying vehicles.…”

Lab-on-a-chip devices: How to close and plug the lab?

“…Johnson et al demonstrated that interfaces between polyimide tubings and silicon/glass chips sealed by Parylene C can withstand pressures as high as 827 kPa (Fig. 12c) [194]. More recently, a novel macro-to-micro interfacing technique was developed by our group (Fig.…”

“…For example, tubings can be connected to (a) a tape covering a paper-based microfluidic, (b) a silicon chip by means of soldering, (c) a LOC device using in-plane insertion of tubings followed by conformal deposition of Parylene C, and (d) a microfluidic chip with mechanical interlocking of tapered tubings. (a) After [137], (b) after [192], and (c) after [194]. structures.…”

Towards an Implantable, Low Flow Micropump That Uses No Power in the Blocked-Flow State

“…Microfluidic interconnects to polyimide microcapillary tubing were created as described in [ 37 ]. Briefly, a 0.17 mm cover glass (18 mm × 18 mm) was adhered to the chip along the interconnect edge to prevent resin from flowing into the microchannels during the direct write step and to provide a clean opening for the insertion of the capillary tubing.…”