DJL

Spermbots are biocompatible hybrid machines that consist of microtubes which are propelled by single spermatozoa and have promising features for powering nano and microdevices. This article presents three approaches on how to improve the performance of such spermbots. First, 20 μm microtubes produce faster spermbots compared to the previously reported 50 μm long microtubes. Furthermore, biofunctionalization by microcontact printing and surface chemistry of biomolecules on the inner tube surface improve the coupling efficiency between sperm cell and microtube, and the addition of caffeine results in a speed boost of the sperm-driven micromotor.

Improved spermbot performance is demonstrated by biofunctionalization of the inner tube surface, shorter tube design, and caffeine addition. Firstly, spermbot velocity is improved by the use of shorter microtubes; secondly, better coupling efficiency is achieved by binding of fibronectin inside the microtube; and finally, caffeine addition gives a temporary speed boost to the spermbot.

Substitutional heterovalent doping represents an effective method to control the optical and electronic properties of nanocrystals (NCs). Highly monodisperse II−VI NCs with deep substitutional dopants are presented. The NCs exhibit stable, dominant, and strong dopant fluorescence, and control over n- and p-type electronic impurities is achieved. Large-scale, bottom-up superlattices of the NCs will speed up their application in electronic devices.

DNA and RNA G-quadruplexes (G4) are unusual nucleic acid structures involved in a number of key biological processes. RNA G-quadruplexes are less studied although recent evidence demonstrates that they are biologically relevant. Compared to DNA quadruplexes, RNA G4 are generally more stable and less polymorphic. Duplexes and quadruplexes may be combined to obtain pure tetrameric species. Here, we investigated whether classical antiparallel duplexes can drive the formation of antiparallel tetramolecular quadruplexes. This concept was first successfully applied to DNA G4. In contrast, RNA G4 were found to be much more unwilling to adopt the forced antiparallel orientation, highlighting that the reason RNA adopts a different structure must not be sought in the loops but in the G-stem structure itself. RNA antiparallel G4 formation is likely to be restricted to a very small set of peculiar sequences, in which other structural features overcome the formidable intrinsic barrier preventing its formation.

All four one: The possibility to force the formation of antiparallel tetramolecular quadruplexes (G4) by using classical antiparallel duplexes was investigated (see figure). This concept was successfully applied to the formation of DNA G4 systems, but mostly failed when RNA was used instead. Therefore, the G-stem structure itself might be responsible for the observation that RNA adopts different structures than DNA.

Precise spatiotemporal control of physiological processes by optogenetic devices inspired by synthetic biology may provide novel treatment opportunities for gene- and cell-based therapies. An erectile optogenetic stimulator (EROS), a synthetic designer guanylate cyclase producing a blue-light-inducible surge of the second messenger cyclic guanosine monophosphate (cGMP) in mammalian cells, enabled blue-light-dependent penile erection associated with occasional ejaculation after illumination of EROS-transfected corpus cavernosum in male rats. Photostimulated short-circuiting of complex psychological, neural, vascular, and endocrine factors to stimulate penile erection in the absence of sexual arousal may foster novel advances in the treatment of erectile dysfunction.

A bolt from the blue: A synthetic designer guanylate cyclase producing a blue-light-inducible surge of the second messenger cyclic guanosine monophosphate (cGMP) in mammalian cells was used as an erectile optogenetic stimulator (EROS). Blue-light-dependent penile erection associated with occasional ejaculation was triggered in male rats by simple illumination of EROS-transfected corpus cavernosum with a portable commercial light-therapy device.

Almost half of solar energy reaching the Earth is in the infrared, and for solar cells, IR absorbing/emitting quantum dots are highly effective photovoltaic materials. As a possible approach to generating such materials, an investigation into the incorporation of group IIB metal ions during the shelling of II–VI and III–V semiconductor core/shell quantum dots is presented. Quantum dot shells consist of ZnS and an additional metal sulphide, obtained from the decomposition of metal dithiocarbamate single-source precursors. Resultant quantum dots are characterized and interrogated using transmission electron microscopy, high-resolution transmission electron microscopy, electron diffraction, time-of-flight-secondary ion mass spectroscopy, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, photoluminescence emission and lifetime spectroscopy, and UV–vis spectroscopy. It is demonstrated that on incorporation of an additional metal sulphide during shelling, photoluminescence properties change dramatically according to the element and indeed, its concentration. Tunable infrared emission is achieved for Hg addition, thus a one-pot method for the synthesis of infrared emitting quantum dots from visible luminescent cores is hereby developed.

Shell formation on core/shell II–VI and III–V semicondutor nanocrystals with the triad of Group IIB metals is presented, with luminescence and effect on quantum yield investigated. Shells are formed from the decomposition of as-synthesized metal dithiocarbamates; stable, single-source precursors for metal sulphides, making this a versatile and facile method for quantum dot shelling.

A multilayered triboelectric nanogenerator (MULTENG) that can be actuated by acoustic waves, vibration of a moving car, and tapping motion is built using a 3D-printing technique. The MULTENG can generate an open-circuit voltage of up to 396 V and a short-circuit current of up to 1.62 mA, and can power 38 LEDs. The layers of the triboelectric generator are made of polyetherimide nanopillars and chalcogenide core–shell nanofibers.