2D conductive nanosheets are central to electronic applications because of their large surface areas and excellent electronic properties. However, tuning the multifunctions and hydrophilicity of conductive nanosheets are still challenging. Herein, a green strategy is developed for fabricating conductive, redox-active, water-soluble nanosheets via the self-assembly of poly(3,4-ethylenedioxythiophene) (PEDOT) on the polydopamine-reduced and sulfonated graphene oxide (PSGO) template. The conductivity and hydrophilicity of nanosheets are highly improved by PSGO. The nanosheets are redox active due to the abundant catechol groups and can be used as versatile nanofillers in developing conductive and adhesive hydrogels. The nanosheets create a mussel-inspired redox environment inside the hydrogel networks and endow the hydrogel with long-term and repeatable adhesiveness. This hydrogel is biocompatible and can be implanted for biosignals detection in vivo. This mussel-inspired strategy for assembling 2D nanosheets can be adapted for producing diverse multifunctional nanomaterials, with various potential applications in bioelectronics.because of their fascinating properties such as large surface areas, numerous active sites, and high conductivity and mechanical strength. [4] In particular, the emerging class of redox-active 2D conductive nanosheets such as covalent organic framework [5] and redox-active heteroatomloaded carbon nanosheets [6] has been used in various areas, e.g., catalysis, solar cells, photochemical water splitting, organic rechargeable battery cathodes, and bioelectronics. The common approach of fabricating conductive nanosheets via mechanical exfoliation lacks effective function tunability. Incorporation of inorganic redox couples such as transition-metal ions has frequently been used to make conductive nanosheets redox active. [7] However, these redox couples often involve toxic and precious-metal ions, and this hinders their biomedical applications. There is therefore an urgent need to develop green and costeffective approaches to fabricating biocompatible, redox-active, and conductive nanosheets for future bioelectronic and biomedical applications.Composites of conductive nanosheets and hydrogels are considered to be promising candidates for use in next-generation soft and flexible bioelectronics. [8] Poly(3,4-ethylenedioxythiophene) (PEDOT) is an ideal conductive material for flexible electronics because of its high electrical conductivity and excellent chemical stability. [9] However, because of the hydrophobicity and intrinsic chemical structure of PEDOT, the production of PEDOT nanosheets and their uniform dispersion in a hydrogel matrix is challenging. In addition, interfacial adhesion between the hydrogel and tissues is of critical importance, especially for electronic skin and implantable bioelectrode. [10] It is desire to develop flexible and tissue-adhesive bioelectronics so that they can tightly integrate with surrounding tissues. Recently, adhesive hydrogels based on mussel-inspired c...

Novel organic photoCORMs based on micelle-encapsulated unsaturated cyclic α-diketones were designed and synthesized. These photoCORMs can be activated by visible light, have potentially low toxicity, allow the delivery of carbon monoxide to be monitored by fluorescence imaging techniques, and thus are useful tools for the study of the biological function of CO.

Increasing acidity is a promising method for bacterial inactivation by inhibiting the synthesis of intracellular proteins at low pH. However, conventional ways of pH control are not reversible, which can cause continuous changes in cellular and biological behaviours and are harmful to the host. Utilizing a photoacid that can reversibly alter pH over two units, we demonstrated a strong bacterial inhibition assisted by visible light.The pH value of the solution reverts back to the original level immediately after the irradiation is stopped.If a photoacid is combined with colistin, the minimum inhibitory concentration (MIC) of colistin on multidrug-resistant (MDR) Pseudomonas aeruginosa can be improved $32 times (from 8 to 0.25 mg mL À1 ), which significantly decreases the toxicity of colistin in clinics. Evidenced by the extremely low toxicity of the photoacid, this strategy is promising in MDR bacteria killing.

This paper describes a nanoparticle enhanced X-ray irradiation based strategy that can be used to kill multidrug resistant (MDR) bacteria. In the proof-of-concept experiment using MDR Pseudomonas aeruginosa (P. aeruginosa) as an example, polyclonal antibody modified bismuth nanoparticles are introduced into bacterial culture to specifically target P. aeruginosa. After washing off uncombined bismuth nanoparticles, the bacteria are irradiated with X-rays, using a setup that mimics a deeply buried wound in humans. Results show that up to 90% of MDR P. aeruginosa are killed in the presence of 200 μg ml(-1) bismuth nanoparticles, whereas only ∼6% are killed in the absence of bismuth nanoparticles when exposed to 40 kVp X-rays for 10 min. The 200 μg ml(-1) bismuth nanoparticles enhance localized X-ray dose by 35 times higher than the control with no nanoparticles. In addition, no significant harmful effects on human cells (HeLa and MG-63 cells) have been observed with 200 μg ml(-1) bismuth nanoparticles and 10 min 40 kVp X-ray irradiation exposures, rendering the potential for future clinical use. Since X-rays can easily penetrate human tissues, this bactericidal strategy has the potential to be used in effectively killing deeply buried MDR bacteria in vivo.

Traditional in vitro nanotoxicity researches are conducted on cultured two-dimensional (2D) monolayer cells and thereby cannot reflect organism response to nanoparticle toxicities at tissue levels. This paper describes a new, high-throughput approach to test in vitro nanotoxicity in three-dimensional (3D) microtissue array, where microtissues are formed by seeding cells in nonsticky microwells, and cells are allowed to aggregate and grow into microtissues with defined size and shape. Nanoparticles attach and diffuse into microtissues gradually, causing radial cytotoxicity among cells, with more cells being killed on the outer layers of the microtissue than inside. Three classical toxicity assays [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT), glucose-6-phosphate dehydrogenase (G6DP), and calcein AM and ethidium homodimer (calcein AM/EthD-1)] have been adopted to verify the feasibility of the proposed approach. Results show that the nanotoxicities derived from this method are significantly lower than that from traditional 2D cultured monolayer cells (p < 0.05). Equipped with a microplate reader or a microscope, the nanotoxicity assay could be completed automatically without transferring the microtissue, ensuring the reliability of toxicity assay. The proposed approach provides a new strategy for high-throughput, simple, and accurate evaluation of nanoparticle toxicities by combining 3D microtissue array with a panel of classical toxicity assays.