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Hydrogen sulfide (H2S) sensors are in urgent demand in the field of hermetic environment detection and metabolic disease diagnosis. However, most of the reported room-temperature (RT) H2S sensors based on transition metal oxides/salts unavoidably suffer from the poisoning effect, resulting in the unrecoverable behavior to restrain their application. Herein, copper(II) chloride-doped polyaniline emeraldine salt (PANI-CuCl2) was devised for RT-recoverable H2S detection, where the copper ion (Cu2+) was designed as a partial substitution of protons (H+) in PANI. The prepared gas sensor exhibited full recovery capability toward 0.25–10 ppm H2S, good repeatability, and long-term stability under 80% RH. Meanwhile, the changes of the PANI-CuCl2during the H2S sensing period were analyzed via multiple analytical methods to reveal the reversible sensing behavior. Results showed that doping of Cu2+not only promoted the PANI’s response through the formation of conductive copper sulfide (CuS) and following H+redoping in the PANI but also facilitated the sensor’s recovery behavior because of the Cu2+regeneration under the H+/oxygen environment. This work not only proves the changes of the interaction between the PANI and Cu2+during the H2S sensing period but also sheds light on designing recoverable H2S sensors based on transition metal salts.

Photon absorption-induced exciton generation plays an important role in determining the photovoltaic properties of donor/acceptor organic solar cells with an inverted architecture. However, the reconstruction of light harvesting and thus exciton generation at different locations within organic inverted device are still not well resolved. Here, we investigate the film depth-dependent light absorption spectra in a small molecule donor/acceptor film. Including depth-dependent spectra into an optical transfer matrix method allows us to reconstruct both film depth- and energy-dependent exciton generation profiles, using which short-circuit current and external quantum efficiency of the inverted device are simulated and compared with the experimental measurements. The film depth-dependent spectroscopy, from which we are able to simultaneously reconstruct light harvesting profile, depth-dependent composition distribution, and vertical energy level variations, provides insights into photovoltaic process. In combination with appropriate material processing methods and device architecture, the method proposed in this work will help optimizing film depth-dependent optical/electronic properties for high-performance solar cells.

The design and synthesis of a novel generation of a nanoscaled platform with imaging-guided therapy remain a real challenge. It can not only improve the imaging sensitivity of tumor tissues for guiding all kinds of treatments but also reduce the harm for healthy tissues. Here, polydopamine (PDA), polyethylene glycol (PEG), and c(RGDyK) peptide (RGD)-modified and cisplatin-loaded Gd2Hf2O7nanoparticles (Gd2Hf2O7@PDA@PEG-Pt-RGD NPs) are designed for magnetic resonance imaging (MRI)-guided combined chemo-/photothermal-/radiotherapy of resistant tumors. The as-prepared NPs display high relaxivity (r1= 38.28 mM–1s–1) as an MRI contrast agent because of their ultrasmall size and surface modification with polyacrylic acid and PDA. Gd2Hf2O7@PDA@PEG-Pt-RGD NPs exhibit pH and NIR dual-stimuli responsiveness for cisplatin release. Based on competent NIR absorption and high X-ray attenuation efficiency, Gd2Hf2O7@PDA@PEG-Pt-RGD NPs show potential photothermal effect by exposing to an 808 nm NIR laser and significantly improve the generation of reactive oxygen species after X-ray radiation. Combined chemo-/photothermal-/radiotherapy can effectively treat the resistant A549R cells, providing the enhanced therapeutic efficiency to cancer tissues and the reduced side effect to healthy tissues. Furthermore, Gd2Hf2O7@PDA@PEG-Pt-RGD NPs present no obvious toxicity during the treatment, which demonstrates the potential as an efficient MRI-guided combined chemo-/photothermal-/radiotherapy nanoplatform for drug-resistant tumors.

A new strategy for designing contrast agents (CAs) based on geometrical confinement will become a competent way to improve the relaxivity of CAs. Herein, a magnetic resonance imaging (MRI) nanoconstruct is fabricated through loading Gd2O3nanoparticles into mesoporous carbon nanospheres, followed by conjugation of poly(ethylene glycol) (PEG) and the c(RGDyK) peptide (Gd2O3@OMCN-PEG-RGD), which could prolong the blood circulation half-life as well as improve the tumor-targeting ability. As a result, the Gd2O3@OMCN-PEG-RGD exhibits an outstandingly high relaxivity (r1= 68.02 mM–1s–1), which is ∼5.3 times higher than that of Gd2O3nanoparticles (r1= 12.74 mM–1s–1). Afterward, both the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide test and H&E staining show that the Gd2O3@OMCN-PEG-RGD has wonderful biocompatibility in vitro and in vivo. Moreover, the in vivo MR images indicate that the Gd2O3@OMCN-PEG-RGD could accumulate in the tumor region more rapidly than Gd2O3@OMCN-PEG. This study presents a facile method to fabricate an MRI CA with excellent T1contrast ability based on geometrical confinement and excellent biocompatibility, which could act as an optimal contender for sensitive in vivo tumor imaging with outstanding targeting ability.

In this report, two biodegradable star-shaped polyasparamide derivatives and four analogues modified with either mannose or folic acid moiety for preferential targeting of a difficult-to-transfect immune cell type, i.e., macrophage, have been synthesized. Each of the prepared star polymers complexes with plasmid DNA to form nanosized particles featuring a core–shell-like morphology. Mannose or folate functionalized star polymers can greatly improve the transfection performance on a macrophage cell line RAW 264.7. As a result, a combination of targeting ligand modification and topological structures of gene carriers is a promising strategy for immune cells-based gene therapy.