Integration of Cell Membranes and Nanotube Transistors

Abstract

We report the integration of a complex biological system and a nanoelectronic device, demonstrating that both components retain their functionality while interacting with each other. As the biological system, we use the cell membrane of Halobacterium salinarum. As the nanoelectronic device, we use a nanotube network transistor, which incorporates many individual nanotubes in such a way that entire patches of cell membrane are contacted by nanotubes. We demonstrate that the biophysical properties of the membrane are preserved, that the nanoelectronic devices still function as transistors, and that the two systems interact. Further, we use the interaction to study the charge distribution in the biological system, finding that the electric dipole of the membrane protein bacteriorhodopsin is located 2/3 of the way from the extracellular to the cytoplasmic side.Nanobioelectronics, the integration of biological processes and molecules with nanoscale fabricated structures, offers the potential for electronic control and sensing of biological systems. 1 As a specific example, carbon nanotubes have been suggested for use as prosthetic nervous implants in organs such as eyes and ears. 2 To achieve this goal requires the parallel preparation 3 of fully functional biological systems and nanoelectronic systems that are integrated together. One major obstacle is the preservation of functionality in both systems. For example, while biological systems ranging from lipids 7 to living cells 2 have been assembled on nanotube substrates, the nanotubes have served only as mechanical supports, without electronic functionality. A second major obstacle is the difference in scale between nanostructures and biological systems. While nanotubes are comparable in size to individual proteins, they are much smaller than cells. Thus, nanotube electronic devices have been used as singlemolecule sensors 5a,7a rather than to communicate with complex biological systems. Here, we achieve integration between a functioning nanotube transistor and a cell membrane. We use nanotube networks, a recently developed class of nanotube devices, to bridge the gap in size between nanotechnology and biotechnology. To demonstrate the power of the approach, we use the nanobioelectronic devices to extract information about the charge distribution in the particular membrane used, thereby contributing to the resolution of a long-standing question about charge distributions within that membrane. 6

A polysaccharide bioprotonic field-effect transistor

“…At the nanoscale, ionic (and protonic) conductivity has attracted increasing interest with the advent of resistive ionic memories 14 , memristors 15,16 , synaptic transistors 17 , and nanofluidics [18][19][20] . In hybrid bionanodevices, biological multifunctionality has been added to carbon nanotubes 21 or silicon nanowires 22 with transmembrane proton conductive proteins. Bionanoelectronic devices 23 that can control the current of ions and protons-a more appropriate language than electrons in nature 24 -are uniquely positioned.…”

Design of a CNFET array for sensing and control in P450 based biochips for multiple drug detection

“…In the present paper, all the P450 proteins present in Table 1 are considered in order to propose an innovative design of a P450 based biochip for multiple-drugs detection based on CNFET logic. It is well know that the carbon nanotubes enhance the detection sensitivity in P450 based biosensors [11,14,16,17]. Thus, functionalizing a CNFET by using the proper P450 isoform is used to obtain both an improvement in drugs detection and a control of each single probe thanks to the FET gate, as shown in Figure 3.…”

Biomedical and Biomedicine Applications of CNTs

“…Field effect transistors (FETs) are constructed by connecting the source and drain of the FET with a single semiconducting SWCNT that forms the conducting channel [57][58][59]. The device detects changes in the electrical characteristics of the FET resulting from molecules interacting with the nanotube.…”

“…CNT network FETs have been integrated with cell membranes. Further research will focus on sensing capabilities in physiological serum [59]. The low limit of detection of NTFETs is characteristic of CNTs responding to the binding of any molecule.…”