Invasive brain implants and tethered optical fibres are typically used in restrained or motion-impaired animals, limiting the control and the decoding of the neural circuitry in freely behaving ones. Here we report the implant- and tether-free optical neurostimulation of deep brain regions by locally injected and untargeted photothermal transducers. The macromolecular transducers, comprising a semiconducting polymer core and an amphiphilic polymer shell, have an average diameter of 40 nanometres and achieve a photothermal conversion of 71% (at 1064 nm), activating the transient receptor potential cation channel subfamily V member 1 (TRPV1) ectopically expressed by an adeno-associated virus in dopaminergic neurons of tyrosine hydroxylase-driven Cre recombinase transgenic mice. The near-transparency of biological tissue in the second near-infrared window enabled the light source to be placed at 50 centimetres above the mouse, at a low incident power density of 10 milliwatt/square millimetre, resulting in the activation, through the scalp and skull, of the dopaminergic neurons in the ventral tegmental area, with minimal thermal damage. The approach is suitable for the neurostimulation of socially interacting mice.

A microneedle (MN) is a micron-sized needle with a height of 10-2000 μm and a width of 10-50 μm, which can penetrate through the epidermis layer to dermal tissue directly without pain. Microneedles are widely used in transdermal drug delivery systems (TDDS) because they are efficient, safe, convenient and painless. Morphologically, microneedles are divided into four types: solid microneedles, coated microneedles, dissolving microneedles, and hollow microneedles. Different types of microneedles play different roles in different research fields. Microneedles also have different characteristics and applications depending on the materials they are made from. In recent years, microneedles have frequently been used to deliver drugs, genes, proteins, RNA, and vaccines, and have achieved amazing therapeutic effect. Meanwhile, a variety of nano-carriers combined with microneedle delivery systems highlight the application of microneedles. The materials, types, and applications of the microneedles are summarized in this review. Overall, this review aims to serve as a foundational study of microneedles and hopes to promote their clinical application.

enhanced activity both under λ > 420 nm and λ > 475 nm light irradiation and to long-term stability. The H 2 production rate of BP/g-C 3 N 4 (384.17 µmol g −1 h −1 ) is comparable to, and even surpasses that of the previously reported, precious metal-loaded photocatalyst under λ > 420 nm light. The efficient charge transfer between BP and g-C 3 N 4 (likely due to formed NP bonds) and broadened photon absorption (supported both experimentally and theoretically) contribute to the excellent photocatalytic performance. The possible mechanisms of H 2 evolution under various forms of light irradiation is unveiled. This work presents a novel, facile method to prepare 2D nanomaterials and provides a successful paradigm for the design of metal-free photocatalysts with improved chargecarrier dynamics for renewable energy conversion. solar fuel technology. For acquiring the above listed beneficial features, visible light-responsive graphitic carbon nitride (g-C 3 N 4 ), a 2D metal-free photocatalyst, has been extensively explored in photocatalysis. Though g-C 3 N 4 was discovered to be feasible for photocatalytic water splitting, obtaining a relatively high efficiency of H 2 production still largely relies on the loading of noble metal cocatalysts because of the high recombination rate of the charge carriers in g-C 3 N 4 . [2] Furthermore, the relatively wide bandgap (2.7 eV) confines its light response mainly into the ultraviolet (UV) range and only slightly into a narrow region of the visible light range (λ < 460 nm). [3] To solve these problems, numerous strategies have been developed, mainly including morphology tuning, doping with metal/nonmetal ions, and heterojunction creation. [4] However, quite limited progresses have been achieved thus far. Aiming to enhance the harvesting of solar light efficiently and economically, the development of novel g-C 3 N 4 -based metal-free photocatalysts with a broader photoresponse range is of great significance.Black phosphorus (BP), a layered material that consists of corrugated atomic planes with strong intralayer chemical bonding and weak interlayer van der Waals interactions, has attracted tremendous interest of material scientists. Since the PhotocatalysisThe ORCID identification number(s) for the author(s) of this article can be found under https://doi.

The most recent progress in high-quality upconversion particle synthesis, rational composite material design, and the combination with plasmonic metals renders upconversion-enhanced NIR photocatalysis increasingly more attractive than ever before.