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Field‐driven transport systems offer great promise for use as biofunctionalized carriers in microrobotics, biomedicine, and cell delivery applications. Despite the construction of artificial microtubules using several micromagnets, which provide a promising transport pathway for the synchronous delivery of microrobotic carriers to the targeted location inside microvascular networks, the selective transport of different microrobotic carriers remains an unexplored challenge. This study demonstrated the selective manipulation and transport of microrobotics along a patterned micromagnet using applied magnetic fields. Owing to varied field strengths, the magnetic beads used as the microrobotic carriers with different sizes revealed varied locomotion, including all of them moving along the same direction, selective rotation, bidirectional locomotion, and all of them moving in a reversed direction. Furthermore, cells immobilized with magnetic beads and nanoparticles also revealed varied locomotion. It is expected that such steering strategies of microrobotic carriers can be used in microvascular channels for the targeted delivery of drugs or cells in an organized manner. [ABSTRACT FROM AUTHOR]

Na2Ti3O7/C prepared by a simple acrylamide-assisted sol–gel method shows promising electro-chemical performance as an anode material for sodium-ion batteries. It maintains ca. 100 mAh·g−1 capacity after 100 cycles at 0.1C rate. What's more, it displays about 206.4, 181.2, 151.8, 129.0, 100.3, and 63.4 mAh g−1 at 0.1, 0.2, 0.5, 1, 2, and 5 C current rate, respectively. A capacity of 156.4 mAh·g−1 is recovered when the current density is back to 0.2 C. Density functional theory (DFT) together with molecular dynamics (MD) is used to reveal the Na+ intercalation and diffusion mechanism. Theoretical calculation shows highly active Na+ migration on the b–c planes, with a minimal 0.22 eV energy barrier and the highest diffusion coefficient of 3.8 × 10−7 cm2 s−1 along the b-axis, at the fully charged state. The high vitality of Na+ is maintained until the intercalation level x is more than 0.5. After that, the mobility of Na+ is greatly prohibited, leading to an energy barrier of more than 0.7 eV and a diffusion coefficient within the range 10−14–10−15 cm2 s−1 at the fully discharged state of Na4Ti3O7. The formation energy convex hull determined by means of cluster expansion enables the calculation of voltage profile and the variation of cell parameters, which reveals the low strain (< 1%) feature during the battery cycles. The calculation of electronic structure also reveals an insulator–metal transition upon the sodiation of the Na2Ti3O7 material. [ABSTRACT FROM AUTHOR]

Herein, sol–gel-synthesized α-Li2TiO3 was evaluated as a new promising anode material for lithium-ion batteries. The results show ultrastable release of discharge capacity within the range of 290–350 mA h g−1 in 400 cycles. Decent rate performances were also observed. A capacity of ca. 113 mA h g−1 was retained at a current density of 3 C. A 2 × 2 × 1 supercell of the lowest energy ordering structure was used in density functional theory simulations. The calculations show that in the intercalation process, Li+ preferentially enters the tetrahedral voids, leading to the activation of lithium-ion diffusion on the a–b plane with a minimal energy barrier of 0.06 eV (compared with 0.82 eV for the fully charged state). The activation of cation mobility at Li+ intercalation and insulator–conductor transition both contribute significantly to the ultrastability of the material. However, Li+ propagation along the c-axis is highly limited during the whole intercalation process. The enumeration of all the ordering structures on the tetrahedral sites shows two intermediate phases, α-Li2.25TiO3 and α-Li3.0TiO3, as observed from the formation energy convex hull. [ABSTRACT FROM AUTHOR]

The collective behavior of colloids in microsystems is characterized by precise micro-object control, broadening the applications of cargo manipulation in drug delivery, microfluidics, and nanotechnology. To further investigate this potential, we introduce a cargo-manipulating platform that utilizes micromagnetic patterns and fluid flow rather than conventional fluidic components. This platform, called the flowless micropump, comprises an encapsulating fluid system within a chip, containing both actuation particles (2.8 μm in diameter) and control targets, thereby eliminating external interactions. This platform enables two distinct modes of cargo manipulation: direct control of nonmagnetic cargo (e.g., MCF-7 and THP-1 cells) and indirect manipulation of particles (e.g., polymer particles) through secondary localized fluid flow. Direct manipulation is achieved via coordinated particle collisions, facilitated by an optimized guiding wall with a height of 25 μm. Conversely, indirect manipulation allows for high-speed control and mode change of individual targets. These manipulation events are achieved using two patterned structures: railway-track and connected half-disk (conductor) patterns. By employing a conductor pattern in conjunction with a railway-track pattern, precise and agile control of microcargo (MCF-7 and THP-1 cells and polymer bead clusters) was achieved at frequencies of 1-3 Hz and a magnetic field strength of 10 mT. This study establishes a programmable platform for designing flowless micropumps with diverse functionalities for various experimental purposes. By using colloidal flow and localized fluid flow generated by the shape of magnetic patterns and semi-three-dimensional (3D) structures, this platform holds significant promise for applications in drug screening, cell-cell interaction studies, and organoid-on-chip research.

We demonstrated a simple one-pot synthesis approach for the controlled composition of homogeneous FePt and phase-controlled heterostructured FePt/Fe 3 O 4 nanocubes (NCs) utilizing 1,2-hexadecanediol and 1-octadecene as the reducing agents, respectively. When the Fe : Pt precursor ratio was varied from 1 : 1 to 4 : 1 and 1,2-hexadecanediol was utilized as the reducing agent, homogeneous FePt NCs were formed, whereas the heterostructures of FePt/Fe 3 O 4 NCs were obtained when utilizing 1-octadecene as the reducing agent at Fe : Pt ratio of 4 : 1. The initial domination of nucleation of Pt-rich species and the subsequent deposition of Fe atoms leads to the formation of homogeneous FePt NCs. Heterostructured FePt/Fe 3 O 4 NCs were obtained by the initial FePt seed formation, which was then followed by the heterogeneous growth of Fe 3 O 4 . The heterostructured FePt/Fe 3 O 4 NCs exhibited two phases, i.e. , FePt phase with a (111) facet of the fcc and Fe 3 O 4 phase with an inverse cubic spinel structure. Moreover, both the FePt and the FePt/Fe 3 O 4 NCs demonstrated almost negligible coercivity, which confirmed a typical superparamagnetic behavior. Furthermore, the cell viability tests of the FePt and FePt/Fe 3 O 4 NCs demonstrated excellent biocompatibilities. Hence, the NCs could be useful for various biomedical applications, including MRI contrast agents, hyperthermia, and as a label in magnetic biochips., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

Although N-shaped fast scan cyclic voltammetry (N-FSCV) is well-established as an electroanalytical method to measure extracellular serotonin concentrations in vivo , it is in need of improvement in both sensitivity and selectivity. Based on our previous studies using fast cyclic square-wave voltammetry (FCSWV) for in vivo dopamine measurements, we have modified this technique to optimize the detection of serotonin in vivo . A series of large amplitude square-shaped potentials was superimposed onto an N-shaped waveform to provide cycling through multiple redox reactions within the N-shaped waveform to enhance the sensitivity and selectivity to serotonin measurement when combined with a two-dimensional voltammogram. N-Shaped fast cyclic square-wave voltammetry (N-FCSWV) showed significantly higher sensitivity to serotonin compared to conventional N-FSCV. In addition, N-FCSWV showed better performance than conventional N-shaped FSCV in differentiating serotonin from its major interferents, dopamine and 5-hydroxyindoleascetic acid (5-HIAA). It was also confirmed that the large amplitude of the square waveform did not influence local neuronal activity, and it could monitor electrical stimulation evoked phasic release of serotonin in the rat substantia nigra pars reticulata (SNr) before and after systemic injection of escitalopram (ESCIT, 10 mg/kg i.p.), a serotonin selective reuptake inhibitor.