as a back contact as a low–work function metal,
whereas the Au foil acted as a high–work function contact. Figure 4D shows the current-voltage
response of Au foil/RuII(bpy)3/InGa junction with
a diode (rectifying) behavior. The inset in Fig. 4D
shows a flexible Au foil with electrogenerated
chemiluminescence from the OLED at an applied
forward bias of 6 V.
To study the single-crystal nature of Au foils,
we prepared an inorganic diode by using electrodeposited Cu2O on Au foil. InGa eutectic was
used to make a rectifying contact to the p-Cu2O,
and the Au foil substrate served as the ohmic
contact. Polycrystalline Cu2O was electrodeposited
on a stainless steel substrate from the same deposition solution at low overpotentials to produce a
sample with a random orientation. Cu2O on both
the Au foil and the stainless steel were deposited
for a constant charge density to maintain similar
thickness. The XRD pattern of Cu2O on stainless
steel with a polycrystalline powder pattern is shown
in fig. S11. Defects or grain boundaries in a material
increase the probability of electron-hole recombination and lower the overall efficiency of the diode
or solar cell. In a single crystal, an ideal diode
quality factor (n) of 1 indicates diffusion-controlled
currents with no electron-hole recombination in
the material, but in polycrystalline materials, n
varies from 2 to 7 (28, 29). The n value for polycrystalline Si also increases with decreasing grain
size (29). Figure 4E shows current-voltage responses for a Cu2O diode on Au foil and stainless
steel. The epitaxial Cu2O had an n of 1.6, whereas
the polycrystalline Cu2O had an n of 3.1 (Fig. 4F).
The higher value of n for polycrystalline Cu2O is
consistent with previous results for films of Cu/
Cu2O Schottky diode solar cells (30).
Single-crystal Au foils offer the order of traditional semiconductors such as Si wafers without
the constraint of a rigid substrate. The foils are
flexible and optically transparent, and show promise for producing flexible and wearable displays,
solar cells, and sensors. The epitaxial growth of
Cu2O and ZnO that we have demonstrated can
be applied to a wide range of inorganic semiconductors such as CdSe, CdTe, and ZnSe for
use in flexible solar cells. Because ZnO is both a
wide-bandgap semiconductor and a piezoelectric
material, it should be possible to produce pressure-sensitive “electronic skin” and LEDs based on the
ZnO/Au system (31, 32). Also, Au is hypoallergenic
and could serve as a platform for wearable sweat
sensors for continuous health monitoring (5). Although this work focused on the production of
ordered substrates for flexible electronics, the
processing method can be used to provide an
inexpensive source of large metallic single crystals. These could serve as ordered substrates for
photovoltaics, high-temperature superconductors,
stress-free microelectromechanical systems (MEMS),
catalysts, underpotential deposition, self-assembled
monolayers, and molecular electronics.
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The material is based on work supported by the U.S.
Department of Energy, Office of Basic Sciences, Division
of Materials Sciences and Engineering, under grants
DE-FG02-08ER46518 (J.A.S.) and DE-SC0008799 (E.C.).
All data are presented in the main paper and supplement.
Materials and Methods
Figs. S1 to S11
12 December 2016; accepted 13 February 2017
Reversion of antibiotic resistance in
Mycobacterium tuberculosis by
Nicolas Blondiaux,1 Martin Moune,1 Matthieu Desroses,2,3 Rosangela Frita,1*
Marion Flipo,2 Vanessa Mathys,4 Karine Soetaert,4 Mehdi Kiass,4 Vincent Delorme,1,5
Kamel Djaout,1 Vincent Trebosc,6,7 Christian Kemmer,6 René Wintjens,8
Alexandre Wohlkönig,9,10 Rudy Antoine,1 Ludovic Huot,1 David Hot,1 Mireia Coscolla,11,12
Julia Feldmann,11,12 Sebastien Gagneux,11,12 Camille Locht,1 Priscille Brodin,1
Marc Gitzinger,6 Benoit Déprez,2† Nicolas Willand,2*† Alain R. Baulard1*†
Antibiotic resistance is one of the biggest threats to human health globally. Alarmingly,
multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis have
now spread worldwide. Some key antituberculosis antibiotics are prodrugs, for which
resistance mechanisms are mainly driven by mutations in the bacterial enzymatic
pathway required for their bioactivation. We have developed drug-like molecules that
activate a cryptic alternative bioactivation pathway of ethionamide in M. tuberculosis,
circumventing the classic activation pathway in which resistance mutations have now
been observed. The first-of-its-kind molecule, named SMARt-420 (Small Molecule
Aborting Resistance), not only fully reverses ethionamide-acquired resistance and
clears ethionamide-resistant infection in mice, it also increases the basal sensitivity of
bacteria to ethionamide.
Antibiotic resistance is a rapidly growing health concern and is observed for many antibacterial agents, both in hospital and in community settings (1, 2). The development of drug resistance—especially rifampicin
resistance (RR), multidrug resistance (MDR)
and extensive drug resistance (XDR)—is parti-
cularly worrisome for tuberculosis (TB) (3). Ap-
proximately 580,000 MDR/RR-TB cases have
occurred in 2015, resulting in about 250,000
deaths. This situation seriously undermines ef-
forts to control the global epidemic of TB and
may soon counteract the slow but continuous
annual decline of ~1.5% observed during the
past 14 years (4).
Discovering new anti-TB therapeutics is difficult (5), and few new drugs have emerged during
the past 30 years. Moreover, because current TB
treatment requires poly-therapeutic approaches,
losing key antibiotics because of the emergence
of drug resistance may impair the efficacy of the