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Metal nanowires are promising building blocks for optoelectronic nanodevices, so their independent and precise manipulation is urgently needed. However, the direct optical manipulation methods are severely hampered due to the high absorption and scattering characteristics of the metal nanowires. Here, a microsphere-assisted indirect optical manipulation method is proposed, and precise manipulation of a single Ag nanowire is demonstrated in liquid. The microsphere is actuated to rotate to generate a microvortex by dynamic optical traps. Under the action of shear stress, the Ag nanowire within the microvortex can be controllably rotated and accurately orientated. By manipulating the position of the microsphere using a single optical trap, a precise positioning of the nanowire can be achieved under the action of pushing force. On this basis, the Ag nanowire-based structures were assembled. This indirect optical manipulation avoids the direct interaction between the light and the nanowires, which makes it independent of both the laser (power, wavelength) and the nanowire (material, size, and shape). Hence, the microsphere-assisted manipulation method is simple and general for independent and precise manipulation of a single nanowire, which is of great significance to the fabrication of optoelectronic nanodevices.

Targeted drug delivery system (DDS) holds exciting prospects in biomedical clinical research and drug development. However, it faces a significant challenge in achieving stable and safe targeted transportation without drug leakage while obtaining precise and controllable drug dosing with a high drug utilization rate and low side effects. Herein, an optical tweezers‐based light‐driven technique is proposed to transport and construct multi‐core/shell microdroplets enveloping drug carriers and target cells as a novel, safe, and efficient targeted DDS. Drug‐loaded microdroplets with core/shell structures are first fabricated by a new and simple injection extrusion method and then it is transported to a target cell by a dynamic optical trap with a low optical power, which ensures no drug leakage, exogenous materials, and biothermal damage are introduced during the drug delivery process. Next, precise drug dosing is realized by pushing the target cell into the drug‐loaded microdroplet under the actions of optical forces, which constructs a multi‐core/shell microdroplet structure with a pure drug environment to improve the drug action efficiency. Moreover, quantitative drug dosing with a high drug utilization rate can also achieved by controlling the sizes/number of drug droplets inside the microdroplets. This light‐driven DDS is of great interest to frontier medical research and disease treatment fields. [ABSTRACT FROM AUTHOR]

Targeted drug delivery and real-time detection both play an important role for studying the specificity of a single cancer cell and the development of anticancer drugs. However, a method that simultaneously enables safe and efficient targeted drug delivery and noninvasive, free-label cell detection is highly desirable but challenging. Here, we report an all-optical method that combines fiber optical tweezers with laser Raman microspectroscopy, which can achieve targeted drug delivery to a single cancer cell using optical manipulation in vitro quickly and accurately by a tapered fiber probe, and simultaneously record the corresponding active characteristics of the targeted cancer cell under the contact of delivered drug through a Raman spectrometer. Using the method, drug delivery and release can be flexibly controlled by turning on/off the trapping laser beam propagating in the fiber, which can avoid the complex systems and is highly autonomous and controllable. Moreover, the detection of cell activity does not require any dye calibration and processing, and it is noninvasive. In addition, for a single suspension cell, optical trapping of the cell using another fiber tip can overcome the low efficiency of targeted drug delivery and the poor stability of the Raman spectrum caused by Brownian motion of the cell. This all-optical method provides a promising approach to conduct pharmacologic studies with the reaction of cancer cell and drugs at the level of a single cell.

Targeted drug delivery and real-time detection both play an important role for studying the specificity of a single cancer cell and the development of anticancer drugs. However, a method that simultaneously enables safe and efficient targeted drug delivery and noninvasive, free-label cell detection is highly desirable but challenging. Here, we report an all-optical method that combines fiber optical tweezers with laser Raman microspectroscopy, which can achieve targeted drug delivery to a single cancer cell using optical manipulation in vitro quickly and accurately by a tapered fiber probe, and simultaneously record the corresponding active characteristics of the targeted cancer cell under the contact of delivered drug through a Raman spectrometer. Using the method, drug delivery and release can be flexibly controlled by turning on/off the trapping laser beam propagating in the fiber, which can avoid the complex systems and is highly autonomous and controllable. Moreover, the detection of cell activity does not require any dye calibration and processing, and it is noninvasive. In addition, for a single suspension cell, optical trapping of the cell using another fiber tip can overcome the low efficiency of targeted drug delivery and the poor stability of the Raman spectrum caused by Brownian motion of the cell. This all-optical method provides a promising approach to conduct pharmacologic studies with the reaction of cancer cell and drugs at the level of a single cell. [ABSTRACT FROM AUTHOR]

Developing well-defined nanostructures with superior surface-enhanced Raman scattering (SERS) performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS2 monolayer with Ag nanowire (NW) and nanoparticle (NP) structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G (R6G) molecules can be achieved at “hotspots” formed in the Ag NW-Ag NP-MoS2 hybrid structure, with an enhancement factor of 106. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10-11 M, as well as reliable reproducibility and good stability. [ABSTRACT FROM AUTHOR]