In Vivo Silicon-Based Flexible Radio Frequency Integrated Circuits Monolithically Encapsulated with Biocompatible Liquid Crystal Polymers

Abstract

Biointegrated electronics have been investigated for various healthcare applications which can introduce biomedical systems into the human body. Silicon-based semiconductors perform significant roles of nerve stimulation, signal analysis, and wireless communication in implantable electronics. However, the current large-scale integration (LSI) chips have limitations in in vivo devices due to their rigid and bulky properties. This paper describes in vivo ultrathin silicon-based liquid crystal polymer (LCP) monolithically encapsulated flexible radio frequency integrated circuits (RFICs) for medical wireless communication. The mechanical stability of the LCP encapsulation is supported by finite element analysis simulation. In vivo electrical reliability and bioaffinity of the LCP monoencapsulated RFIC devices are confirmed in rats. In vitro accelerated soak tests are performed with Arrhenius method to estimate the lifetime of LCP monoencapsulated RFICs in a live body. The work could provide an approach to flexible LSI in biointegrated electronics such as an artificial retina and wireless body sensor networks.

Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

“…f Surface morphology of the inkjet printed C/T-MoS 2 where the SEM reveals platelet size to be well below 1 µm on average, and the higher packing density leading to enhanced inter-platelet connectivity compared to the drop cast material in c. PL spectra of g drop cast C/T-MoS 2 and h printed C/T-MoS 2 with the respective imaged regions for PL and Raman shown in the bottom right insets of g and h; the drop cast sample in g did not exhibit any narrow-band luminescence peaks, which is an indication that the drop cast C/T-MoS 2 ink is comprised of bulk material as also noted in Ref. 28. The PL spectra of the inkjet printed C/T-MoS 2 indicates two emission bands centered at the Excitonic A peak at~1.88 eV and the Excitonic B peak at~1.97 eV, whereas the indirectI peak occurs at~1.29 eV.…”

“…For the application considered here in retinal prosthesis, poly-di-methylsiloxane (PDMS) encapsulation can be used to further restrict the dislodging of MoS 2 nanosheets into the fluidic environments of the body. The biocompatible nature of PDMS is well established, 28 and its transparent Electrical transport of inkjet printed structures and ink characterization To explore the electrical properties of the dispersions, graphene and MoS 2 inks were first drop cast onto polyimide substrates and annealed at 330°C for 3 h, after which point the electrical transport properties were measured. The data are shown by the I-V Characteristics in Fig.…”

Self-powered flexible inorganic electronic system

“…Many researchers have demonstrated advanced approaches to self-powered flexible inorganic devices, including energy harvesters [1,2], batteries [3,4], high-density memories [5,6], large-scale integration (LSI) [7,8], light-emitting diodes (LEDs) [9,10], and sensors [11][12][13]. In addition, there have been several efforts to realize multifunctional self-powered flexible systems that combine these flexible units on a single plastic substrate [14,15].…”

“…In addition, there have been several efforts to realize multifunctional self-powered flexible systems that combine these flexible units on a single plastic substrate [14,15]. Such systems can be placed on unconventional surfaces where traditional bulk devices are difficult to access and install, such as spatially-isolated and curvilinear regions of infrastructures and human bodies [7,12,14,15].…”

Functional integrity of flexible n-channel metal–oxide–semiconductor field-effect transistors on a reversibly bistable platform

“…While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin, foldable ones without compromising long-term performance and reliability. [2][3][4][5] Recent research in flexible [6][7][8][9][10][11][12][13][14][15][16][17] and stretchable [18][19][20][21][22][23][24][25][26][27][28][29] electronics shows that flexibility has emerged as a central feature and game-changer, allowing not only for large-scale deployment of such devices in what is currently referred to as macroelectronics, 30 but also opening the possibility of integration of flexible electronics on mechanically flexible and reversibly bistable platforms. 31 Flexible display devices are arguably one of the most researched topics [32][33][34][35] in the scholarly world, and most products on the market are based on organic light-emitting diode (OLED) technology and active thin-film organic devices.…”