Polymeric packaging for fully implantable wireless neural microsensors

Abstract

We present polymeric packaging methods used for subcutaneous, fully implantable, broadband, and wireless neurosensors. A new tool for accelerated testing and characterization of biocompatible polymeric packaging materials and processes is described along with specialized test units to simulate our fully implantable neurosensor components, materials and fabrication processes. A brief description of the implantable systems is presented along with their current encapsulation methods based on polydimethylsiloxane (PDMS). Results from in-vivo testing of multiple implanted neurosensors in swine and non-human primates are presented. Finally, a novel augmenting polymer thin film material to complement the currently employed PDMS is introduced. This thin layer coating material is based on the Plasma Enhanced Chemical Vapor Deposition (PECVD) process of Hexamethyldisiloxane (HMDSO) and Oxygen (O2).

Non‐hermetic packaging of biomedical microsystems from a materials perspective: A review

“…Although/A174 is low-cost and easy to apply by dip coating, its efficiency is limited on certain surfaces such as metals and it often impacts the cleanliness of the process, which might reduce the long-term durability of the coating. Plasma has been used to treat the surface of the substrates prior to parylene deposition, resulting in a parylene film with same properties but longer durability in terms of adhesion to the substrate (Zeniieh et al, 2013), (Aceros, Ming Yin, Borton, Patterson, & Nurmikko, 2012), (Rezai, Selvaganapathy, & Wohl, 2011).…”

“…Flexible polymeric materials, such as thermoplastic polyurethanes (TPUs) (Bergmeister et al, 2015), polyimide (Palopoli‐Trojani et al, 2016; Rubehn & Stieglitz, 2010; Woods et al, 2018), parylene (Agarwal et al, 2018; Chang et al, 2013; Lecomte et al, 2017; Rodger et al, 2006; Shapero et al, 2016), polydimethylsiloxane (PDMS; Lachhman et al, 2012; Wang et al, 2015; Aceros, Yin, et al, 2012; Ko, Wang, & Lachhman, 2015; Brancato, Weydts, Oosterlinck, Herijgers, & Puers, 2017; Chong, Lou, Bogie, Zorman, & Majerus, 2019; Guo et al, 2013; Kim, Lee, et al, 2012; Lee & Cho, 2005; Lin et al, 2018; Majerus et al, 2018; Majerus, Dunning, Potkay, & Bogie, 2017) and liquid crystal polymer (LCP) (Lee et al, 2011), (Chen et al, 2006; Dean, Pack, Sanders, & Reiner, 2005; Jeong et al, 2015; Park, Jeong, Moon, Kim, & Kim, 2016; Schuettler & Stieglitz, 2013), have many properties that are attractive for non‐hermetic packaging. Table 1 offers a summary of these properties.…”