Molybdenum Disulfide‐Based Tubular Microengines: Toward Biomedical Applications

Abstract

2D molybdenum disulfide (MoS2) is herein explored as an advanced surface material in the fabrication of powerful tubular microengines. The new catalytic self‐propelled open‐tube bilayer microengines have been fabricated using a template electrodeposition and couple the unique properties of sp2 hybridized MoS2 with highly reactive inner granular Pt catalytic structures. The MoS2/metal microengines display extremely efficient bubble propulsion, reflecting the granular structure of the inner catalytic platinum or gold layers (compared to the smooth metal surfaces of common micromotors). The efficient movement of functionalized MoS2 micromotors can address challenges imposed by slow mass transport processes involved in various applications of MoS2. The delocalized electron network of the MoS2 outer layer facilitates π–π stacking interactions and endows the tubular microengines with a diverse array of capabilities. These are demonstrated here for efficient loading and release of the drug doxorubicin, and rapid and sensitive “OFF–ON” fluorescent detection of important nucleic acids (miRNA‐21) and proteins (thrombin) using microengines modified with dye‐labeled single‐stranded DNA and aptamer, respectively. Such coupling of the attractive capabilities of 2D‐MoS2 nanosheets with rapidly moving microengines provides an opportunity to develop multifunctional micromachines for diverse biomedical applications ranging from efficient drug delivery to the detection of important bioanalytes.

Magnetic Fields Enhanced the Performance of Tubular Dichalcogenide Micromotors at Low Hydrogen Peroxide Levels

“…Platinum is amperometrically deposited at À0.4 Vf or 750 s. MoS 2 and PEDOT micromotors were prepared following by previously described protocols. [13,18] Scanning electron microscopy (SEM) images were obtained with a JEOL 6335 Fm icroscope (JEOL USA, Massachusetts, United States) coupled with aX flash detector 4010 (Bruker,M assachusetts, United States). The acceleration voltage was set at 20 kV.T he surface profiles of the micromotors were obtained by an atomic force microscopy system, Nanoscope IIIa (Veeco), operating in the dynamic mode.…”

“…In this work, we studied the influence of externalm agnetic fields on the performance of TMD-based tubular micromotors containing Ni and Pt layers.T MDs provide al arge surface area, whicha long with their good electrical conductivity, facilitatet he growth of high surface inner catalytic layers. [13] The speed boost experienced by micromotors under the effect of applied magnetic fields is modeled by combining solid thrust models previously reported [7,10,12] with computational tools, hence giving aw ell-founded explanationb ased upon both experimental evidence and theoretical propulsion models. We will illustrate by numerical simulations how the application of magnetic fields results in an acceleration of the overall speed,m ainly due to ac hange in the flow regime from turbulentt ol aminar and to an increase in the capillaryf orce exertedb yt he generated bubbles.…”

Bio‐Conjugated Advanced Materials for Targeted Disease Theranostics

“…The ATP aptamer was decorated with Ce6, whose fluorescence was quenched due to fluorescence resonance energy transfer (FRET), but recovered after selective recognition between the aptamers and ATP in HeLa cancer cells (Figure 15c). A dye‐labeled aptamer was additionally linked to 2D MoS 2 , which facilitated the sensing of miRNA‐21 and thrombin . A reported 2D MoS 2 modified with PEG, was self‐assembled into clusters and doped with CuS nanoparticles and DOX for A549 cancer theranostics through the use of AS1411 aptamer, with the PTT‐assisted drug release and photothermal imaging shown in both cells and tumor‐bearing mice ( Figure a).…”

“…A dye-labeled aptamer was additionally linked to 2D MoS 2 , which facilitated the sensing of miRNA-21 and thrombin. [163] A reported 2D MoS 2 modified with PEG, was self-assembled into clusters and doped with CuS nanoparticles and DOX for A549 cancer theranostics through the use of AS1411 aptamer, [164] with the PTT-assisted drug release and photothermal imaging shown in both cells and tumor-bearing mice (Figure 16a). A MnO 2 nanolayer [165] coated with oxidized UCNPs and aptamer sgc8 was reported to selectively target circulating tumor cells.…”

Chemotactic Guidance of Synthetic Organic/Inorganic Payloads Functionalized Sperm Micromotors

“…At lower pH, the hydrogen bonding between DOX and amine-functionalized Fe 2 O 3 NPs breaks apart due to the protonation of the amine group, contributing to the increase of the DOX solution concentration. [45] In addition, by using pH-sensitive polymers as drug carriers, it is possible to release doxorubicin at endosomal pH values, leading to more practical in vivo applications of FSFSMs. [46] To study the in vitro cytotoxicity of the Fe 2 O 3 @DOX functionalized FSFSMs against human ovarian cancer cells, the FSFSMs were incubated with SKOV-3 cells (5000 cells per 100 µL culture medium) for 24 h at 37 °C.…”