Awards Submission: Live Bacterium Wrapping with Graphene Peptide Nano-Swaddler: a New Paradigm for Electron Microscopy and Raman Enhancement

Integration of the process complexity of biological systems with the unique properties of nanoscale materials via bio-nano interfacing has metamorphosed nanotechnology. Here we demonstrate for the first time swaddling of a live bacterium with ~ 1 nm thick protein-modified-Graphene and apply it for high vacuum (< 10-5 Torr) Transmission Electron Microscopy (TEM) of wet bacteria (> 90 % water intact) with 3.5 fold reduced cellular shrinkage and significantly reduced qualitative cell surface damage. In this proof-of-concept study, we used chemically synthesized Graphene Oxide (GO) functionalized with Concanavalin – A protein molecules, which have a highly specific complementary chemistry with gram positive bacterial cell surface moieties, to instantaneously (< 1 minute) and hermetically wrap Bacillus cereus and Bacillus subtilis. Dye permeation studies confirmed the impermeability of these graphene-protein-nano-swaddlers (GPNSs), vindicating the efficient compartmentalization of the bacterial cell, consistent with the theoretical predictions. Further, ~ 300 % chemical enhancement of the Raman signal was observed upon wrapping a bacterium attributed to the charge transfer from graphenic islands on the GPNS wraps. We expect this versatile bio-nano interfacing process to facilitate among others facile wet TEM imaging of diverse biological systems including bio-molecules and cellular systems, spectroscopic signal amplification, bio-actuated MEMS & transistors, biocompatible-protective coating, and circuitry to interface living cells.