An insect heart (dorsal vessel) is well suited as an environmentally robust bioactuator since insect tissue is generally robust over culture conditions compared with mammalian tissue. In this paper, the applicability of a caterpillar dorsal vessel to a bioactuator was assessed by fabricating a micropillar actuator driven by dorsal vessel tissue and evaluating the response to electrical pulse stimuli. The actuator worked autonomously for more than 90 days at 25 °C without any maintenance. The average frequency and displacement for 30 s on the 28th day of culturing were 0.83 Hz and 41 μm, respectively. Furthermore, as a regulation method for the dorsal vessel, electrical pulse stimuli were applied to the micropillar actuator. The contractile delay was about 50 ms. A twitch contraction was evoked by electrical pulse stimulus at 20 ms in duration and 10 volts in amplitude. A tetanic contraction was observed when stimuli over 10 Hz were applied.

This report presents the functioning of a molecular memory device with azo-group-functionalized molecular-junctions between metal nanoelectrodes. These junctions are fabricated by a novel electrostatic-assembly process to incorporate azo-group containing polyelectrolyte (AP) between oppositely charged gold nanoparticles (GNP), functioning as nanoelectrodes. The device exhibits a bistable electronic memory effect induced by charge-transfer between AP and GNP, which can be controlled by photo-excitation of the AP. The ON and OFF memory states were found to have a rectification in the range of ∼5000 – 10000. This study will open avenues for development of next-generation molecular systems and devices to produce novel optoelectronic properties.

Nanosystems operating in liquid media may suffer from random thermal fluctuations. Some natural nanosystems, e.g. biomolecular motors, which survive in an environment where the energy required for bio-processes is comparable to thermal energy, exploit these random fluctuations to generate a controllable unidirectional movement. Inspired by the nature, a transportation system of nanobeads achieved by exploiting Brownian motion were proposed and realized. This decreases energy consumption and saves the energy compared to ordinal pure electric or magnetic drive. In this paper we present a linear Brownian motor with a 3-phase electrostatic rectification aimed for unidirectional transport of nanobeads in microfluidic channels. The transport of the beads is performed in 1 μm deep, 2 μm wide PDMS microchannels, which constrain three-dimensional random motion of nanobeads into 1D fluctuation, so-called tamed Brownian motion. We have experimentally traced the rectified motion of nanobeads and observed the shift in the beam distribution as a function of applied voltage. The detailed computational analysis on the importance of switching sequence on the speed performance of motor is performed and compared with the experimental results showing a good agreement.

We have proposed a novel use of pulsating living cells as a driving source for a micro bio-actuator. Cardiyomyocytes contract autonomously using chemical energy. But, contractile force of a single cardiomyocyte is not enough to actuate a micro robot or a mechanical system. So it is necessary to reconstruct cardiomyocytes to increase the ability to contract. We focused on the reconstruction of cardiomyocytes using a basement membrane protein mixture. In this paper, we fabricated a prototype cardiomyocyte gel structure. We confirmed that the ring-shaped cardiomyocyte gel structure condensed around the central cylinder within the PDMS mold and contracted synchronously and autonomously.

P-protein bodies (forisomes), in phloem cells of legumes, transform the chemical free energy of their reaction with alkaline earth metal ions into mechanical energy. In addition to using the bending of glass fibers, micromechanical forces generated by the switching of forisomes in aqueous solutions were measured by monitoring the bending of microscale polymer cantilever beams. The forisomes were fixed by chemisorption to the tips of four orthogonal beams of a BioMEMS microsystem designed and manufactured using the process of sacrificial layer micromolding. The sensor layout allows force measurements in the longitudinal and radial direction of the forisomes. For different forisomes a longitudinal force in the range from 84-136 nN and a radial force of 22-61 nN were measured.

We propose that a thermo-electrical control system for rapid and reversible actuation of biomolecular motors and their partner filaments can also be used to study molecular mechanisms of cardiovascular diseases. We have previously used this device to evaluate the temperature-dependence of unregulated (absence of cardiac Ca2+-regulatory proteins tropomyosin, α-Tm, and troponin, Tn) actin filament sliding powered by myosin motors, which hydrolyze ATP. These assays using the thermo-electric controller can also be applied to regulated thin filaments (F actin plus α-Tm and Tn) to obtain energetic parameters and functional correlates of structural stability at the level of single filaments. This allows us not only to examine Ca2+-dependent sliding of thin filaments, but also to test for altered function of clinically relevant mutations of cardiac myofilament proteins such as those identified in familial hypertrophic cardiomyopathy (FHC).

Stimulus responsive liquid crystal nanorods, 60 μm in length and 200 nm in diameter, were fabricated by a template synthesis technique. The liquid crystal, RM 257, is a reactive monomer which polymerizes with the application of UV light. After polymerization the liquid crystal's orientational order is permanently “frozen”. Therefore, the subsequent structures are temperature independent after curing. In this study the liquid crystal was confined in the pores of Anopore membranes before curing, which results in rod structures after photo-polymerization. After fabrication, the rods were observed under the application of both AC and DC electric fields. DC fields were noted by either up and down or translational movement of the rods. Application of AC fields resulted in random movement of the rods.