A Subcutaneous Biochip for Remote Monitoring of Human Metabolism: Packaging and Biocompatibility Assessment

Abstract

Abstract-This paper represents the extended version of the conference paper "Developing highly-integrated subcutaneous biochips for remote monitoring of human metabolism" presented at the IEEE Sensors Conference 2012, and presents data on assembly, packaging and short term in vitro and in vivo biocompatibility evaluation of a fully implantable biosensor array. The device was realized integrating three building blocks: 1) a multielectrode platform; 2) an inductive coil; and 3) an integrated circuit. The entire system measures 2.2 mm × 2.2 mm × 15 mm. Corrosion of electronic components and leaking of potentially hazardous substances in the body is prevented with a conformal coating of Parylene C, while an outer package of medical grade silicone was employed to create a soft shell suitable for implantation. Biocompatibility experiments did not show in vitro cytotoxicity in the considered period of 7 days, while comparison between 7 and 30 days in vivo implantations showed significant reduction of the inflammatory response in time, suggesting normal host recovery.

Biocompatible packagings for fully implantable multi-panel devices for remote monitoring of metabolism

“…In this paper we compare three different packaging realized with different shape, size and with different materials. However, they all share some common features: (i) MWCNTs were entrapped in a chitosan matrix to prevent the potential toxicity due to their nano-particle nature; (ii) to prevent the corrosion of electronic components due to the contact with biologic fluids, and to prevent the leaking of potential hazardous substances, a coating of Parylene C was deposited [8,9]; (iii) a biocompatible packaging was realized, as, for an implantable sensor, it is essential for a correct wound healing, and for ensuring prolonged sensor functionality. The main differences between the three systems are: (i) the shape of the device; (ii) the shape of the packaging in silicone; (iii) the composition of the membrane that covers the sensors; (iv) the composition of the external packaging.…”

“…3, suggest that after 30 days the host seems to accept the insert. Comparison with the commercial chip, level of neutrophil, and biocompatibility tests with cell cultures for the first version of the packaging have been published in [8]. Fig.…”

“…Figure 1A shows the photograph of the first implantable device. The passive sensing platform measures 2.2x15mm, and host five independent Pt working electrodes (WE) with common reference (RE) and counter (CE) electrodes [8]. Figure 1B and 1C show the photographs of the second and third version of the implantable device, respectively.…”

E-health: From sensors to systems

“…An example and prototype of a future implantable sensing system for monitoring human metabolism [3] is shown in Figure 1. Examples of molecules that can be monitored include glucose, lactate, cholesterol, ATP, glutamate and others.…”

“…An electronic patch on the body produces the inductive field to power the implant, receives the backscattered data, and transmits it to a base station using the Bluetooth standard. [3].…”