Microtubule nanotubes are found in every living eukaryotic cells; these are formed by reversible polymerization of the tubulin protein, and their hollow fibers are filled with uniquely arranged water molecules. Here we measure single tubulin molecule and single brain-neuron extracted microtubule nanowire with and without water channel inside to unravel their unique electronic and optical properties for the first time. We demonstrate that the energy levels of a single tubulin protein and single microtubule made of 40,000 tubulin dimers are identical unlike conventional materials. Moreover, the transmitted ac power and the transient fluorescence decay (single photon count) are independent of the microtubule length. Even more remarkable is the fact that the microtubule nanowire is more conducting than a single protein molecule that constitutes the nanowire. Microtubule's vibrational peaks condense to a single mode that controls the emergence of size independent electronic/optical properties, and automated noise alleviation, which disappear when the atomic water core is released from the inner cylinder. We have carried out several tricky state-of-the-art experiments and identified the electromagnetic resonance peaks of single microtubule reliably. The resonant vibrations established that the condensation of energy levels and periodic oscillation of unique energy fringes on the microtubule surface, emerge as the atomic water core resonantly integrates all proteins around it such that the nanotube irrespective of its size functions like a single protein molecule. Thus, a monomolecular water channel residing inside the protein-cylinder displays an unprecedented control in governing the tantalizing electronic and optical properties of microtubule.
As we bring tubulin protein molecules one by one into the vicinity, they self-assemble and entire event we capture live via quantum tunneling. We observe how these molecules form a linear chain and then chains self-assemble into 2D sheet, an essential for microtubule, —fundamental nano-tube in a cellular life form. Even without using GTP, or any chemical reaction, but applying particular ac signal using specially designed antenna around atomic sharp tip we could carry out the self-assembly, however, if there is no electromagnetic pumping, no self-assembly is observed. In order to verify this atomic scale observation, we have built an artificial cell-like environment with nano-scale engineering and repeated spontaneous growth of tubulin protein to its complex with and without electromagnetic signal. We used 64 combinations of plant, animal and fungi tubulins and several doping molecules used as drug, and repeatedly observed that the long reported common frequency region where protein folds mechanically and its structures vibrate electromagnetically. Under pumping, the growth process exhibits a unique organized behavior unprecedented otherwise. Thus, “common frequency point” is proposed as a tool to regulate protein complex related diseases in the future.
We demonstrate that a single brain-neuron-extracted microtubule is a memory-switching element, whose hysteresis loss is nearly zero. Our study shows how a memory-state forms in the nanowire and how its protein arrangement symmetry is related to the conducting-state written in the device, thus, enabling it to store and process ∼500 distinct bits, with 2 pA resolution between 1 nA and 1 pA. Its random access memory is an analogue of flash memory switch used in a computer chip. Using scanning tunneling microscope imaging, we demonstrate how single proteins behave inside the nanowire when this 3.5 billion years old nanowire processes memory-bits.
A new mechanism is proposed to explain the origin of negative differential resistance (NDR) in a strongly coupled single molecule-metal junction. A first-principles quantum transport calculation in a Fe-terpyridine linker molecule sandwiched between a pair of gold electrodes is presented. Upon increasing the applied bias, it is found that a new phase in the broken symmetry wave function of the molecule emerges from the mixing of occupied and unoccupied molecular orbitals. As a consequence, a nonlinear change in the coupling between the molecule and the lead is evolved resulting in NDR. This model can be used to explain NDR in other classes of metal-molecule junction devices.
We have observed a large electrical conductance switching (ON:OFF ratio=105) in single-layer sandwich structures based on organic molecules at room temperature. The switching devices showed an associated memory effect for data-storage applications. We could write or erase a state and read it for many cycles. In switching devices, the active semiconductor retained its high conducting state until a reverse voltage erased it. A high conducting state arose due to restoration of conjugation in the molecule via electroreduction. Such a high ON–OFF ratio in a single layer sandwich structure, as compared to contemporary switching devices, is due to low off-state leakage current. The concept of conjugation restoration has been verified in supramolecular structures by adding donor groups to the molecule, which resulted in increased off-state current and hence lower ON–OFF ratio. Our work set a generalized example of selecting organic molecules to obtain higher ON–OFF ratio in molecular switching devices.
We have demonstrated conductance switching between multilevel states in devices based on Rose Bengal molecules embedded in supramolecular matrices. Two mechanisms, namely electroreduction and conformational change of the molecules, resulting in conjugation modification have been proposed to be applicable in these devices. In a low voltage region, reverse-bias induced electroreduction of Rose Bengal facilitated conjugation restoration in the backbone of the molecule and, hence, switching to a high-conducting state. At high biases, the two perpendicular planes present in Rose Bengal, which have permanent dipole moments, allowed forward-bias induced conformation change to occur, and results in conductance switching. We have demonstrated how the devices can switch between two pair of conducting states for random-access memory and read-only memory applications for several hours.
Current computers operate at enormous speeds of ~10^13 bits/s, but their
principle of sequential logic operation has remained unchanged since the 1950s.
Though our brain is much slower on a per-neuron base (~10^3 firings/s), it is
capable of remarkable decision-making based on the collective operations of
millions of neurons at a time in ever-evolving neural circuitry. Here we use
molecular switches to build an assembly where each molecule communicates-like
neurons-with many neighbors simultaneously. The assembly's ability to
reconfigure itself spontaneously for a new problem allows us to realize
conventional computing constructs like logic gates and Voronoi decompositions,
as well as to reproduce two natural phenomena: heat diffusion and the mutation
of normal cells to cancer cells. This is a shift from the current static
computing paradigm of serial bit-processing to a regime in which a large number
of bits are processed in parallel in dynamically changing hardware.Comment: 25 pages, 6 figure
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