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The effect of surfactant, polymer, and tailor-made additives on the crystallization of γ-aminobutyric acid (GABA) was studied in this work. Cooling crystallization of GABA in water yielded plate-like crystals. In the presence of sodium stearate, polyhedral block-like crystals of GABA were obtained. Hydroxyethyl cellulose (HEC) led to rod-like crystals, in which the morphology was associated with additive concentrations. Six kinds of amino acids were used as tailor-made additives, and they exhibit different influences on crystal shape and size. The induction time of GABA was determined in the absence and presence of additives. The results showed that sodium stearate promoted nucleation, while HEC, l-Lysine, l-histidine, and l-tyrosine inhibited nucleation. Crystal face indexing, Hirshfeld surface analysis, and molecular dynamics (MD) simulation in aqueous solution-crystal systems were carried out to investigate the affecting factors of different crystal faces. The polymer additive was selected as an example during MD simulation to calculate intermolecular interactions between the crystal face and solvent or additive. The effect of the additive on the mobility of the solute in solution was also evaluated by mean-square displacement. The additive offers an effective approach for changing crystal morphology and particle size and adapting it to different production requirements., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

The crucial roles that glycans play in biological systems are determined by their structures. However, the analysis of glycan structures still has numerous bottlenecks due to their inherent complexities. The nanopore technology has emerged as a powerful sensor for DNA sequencing and peptide detection. This has a significant impact on the development of a related research area. Currently, nanopores are beginning to be applied for the detection of simple glycans, but the analysis of complex glycans by this technology is still challenging. Here, we designed an engineered α-hemolysin nanopore M113R/T115A to achieve the sensing of complex glycans at micromolar concentrations and under label-free conditions. By extracting characteristic features to depict a three-dimensional (3D) scatter plot, glycans with different numbers of functional groups, various chain lengths ranging from disaccharide to decasaccharide, and distinct glycosidic linkages could be distinguished. Molecular dynamics (MD) simulations show different behaviors of glycans with β1,3- or β1,4-glycosidic bonds in nanopores. More importantly, the designed nanopore system permitted the discrimination of each glycan isomer with different lengths in a mixture with a separation ratio of over 0.9. This work represents a proof-of-concept demonstration that complex glycans can be analyzed using nanopore sequencing technology.

Tetrabromobisphenol A (TBBPA), the most extensively utilized brominated flame retardant, has raised growing concerns regarding its environmental and health risks. Neurovascular formation is essential for metabolically supporting neuronal networks. However, previous studies primarily concerned the neuronal injuries of TBBPA, its impact on the neurovascularture, and molecular mechanism, which are yet to be elucidated. In this study, 5, 30, 100, 300 μg/L of TBBPA were administered to Tg (fli1a: eGFP) zebrafish larvae at 2-72 h postfertilization (hpf). The findings revealed that TBBPA impaired cerebral and ocular angiogenesis in zebrafish. Metabolomics analysis showed that TBBPA-treated neuroendothelial cells exhibited disruption of the TCA cycle and the Warburg effect pathway. TBBPA induced a significant reduction in glycolysis and mitochondrial ATP production rates, accompanied by mitochondrial fragmentation and an increase in mitochondrial reactive oxygen species (mitoROS) production in neuroendothelial cells. The supplementation of alpha-ketoglutaric acid, a key metabolite of the TCA cycle, mitigated TBBPA-induced mitochondrial damage, reduced mitoROS production, and restored angiogenesis in zebrafish larvae. Our results suggested that TBBPA exposure impeded neurovascular injury via mitochondrial metabolic perturbation mediated by mitoROS signaling, providing novel insight into the neurovascular toxicity and mode of action of TBBPA.

Halide perovskites have emerged as highly promising materials for ionizing radiation detection due to their exceptional characteristics, including a large mobility-lifetime product, strong stopping power, tunable band gap, and cost-effective crystal growth via solution processes. Semiconductor-type X-ray detectors employing various micro/nano perovskite materials have shown impressive progress in achieving heightened sensitivity and lower detection limits. Here, we present a comprehensive review of the applications of micro/nano perovskite materials for direct type X-ray detection, with a focus on the requirements for micro/nano crystal assembly and device properties in advanced X-ray detectors. We explore diverse processing techniques and optoelectronic considerations applied to perovskite X-ray detectors. Additionally, this review highlights the challenges and promising opportunities for perovskite X-ray detector arrays in real-world applications, potentially necessitating further research efforts.

Fibrous nanomaterials containing silica, titanium oxide, and carbon nanotubes are notoriously known for their undesirable inflammatory responses and associated toxicities that have been extensively studied in the environmental and occupational toxicology fields. Biopersistance and inflammation of "hard" nanofibers prevent their broader biomedical applications. To utilize the structural benefits of fibrous nanomaterials for functionalization with moieties of therapeutic significance while preventing undesirable immune responses, researchers employ natural biopolymers─RNA and DNA─to design "soft" and biodegradable nanomaterials with controlled immunorecognition. Nucleic acid nanofibers have been shown to be safe and efficacious in applications that do not require their delivery into the cells such as the regulation of blood coagulation. Previous studies demonstrated that unlike traditional therapeutic nucleic acids (e.g., CpG DNA oligonucleotides) nucleic acid nanoparticles (NANPs), when used without a carrier, are not internalized by the immune cells and, as such, do not induce undesirable cytokine responses. In contrast, intracellular delivery of NANPs results in cytokine responses that are dependent on the physicochemical properties of these nanomaterials. However, the structure-activity relationship of innate immune responses to intracellularly delivered fibrous NANPs is poorly understood. Herein, we employ the intracellular delivery of model RNA/DNA nanofibers functionalized with G-quadruplex-based DNA aptamers to investigate how their structural properties influence cytokine responses. We demonstrate that nanofibers' scaffolds delivered to the immune cells using lipofectamine induce interferon response via the cGAS-STING signaling pathway activation and that DNA aptamers incorporation shields the fibers from recognition by cGAS and results in a lower interferon response. This structure-activity relationship study expands the current knowledge base to inform future practical applications of intracellularly delivered NANPs as vaccine adjuvants and immunotherapies.

The redox properties of titania films grown by ALD on SBA-15, a silica-based mesoporous material, were characterized as a function of thickness (that is, the number of ALD cycles used). 29 Si CP/MAS NMR helped to identify the nature of the surface species that form in the initial stages of deposition, and infrared absorption spectroscopy was used to follow the transition from silica to titania surfaces. The reducibility of the titania sites by CO and H 2 was studied ex situ using EPR and in situ with ambient-pressure XPS. It was determined that the titania ALD films are amorphous and easier to reduce than crystalline titania and that the reduction is reversible. A transition in the nature of the surface was also observed, with unique mixed Si-O-Ti sites forming during the first few ALD cycles and a more typical titania surface progressively developing as the film grows in thickness.

As mesenchymal stem-cell-derived small extracellular vesicles (MSC-sEVs) have been widely applied in treatment of degenerative diseases, it is essential to improve their cargo delivery efficiency in specific microenvironments of lesions. However, the interaction between the microenvironment of recipient cells and MSC-sEVs remains poorly understood. Herein, we find that the cargo delivery efficiency of MSC-sEVs was significantly reduced under hypoxia in inflammaging nucleus pulposus cells due to activated endocytic recycling of MSC-sEVs. Hypoxia-inducible factor-1 (HIF-1)-induced upregulated RCP (also known as RAB11FIP1) is shown to promote the Rab11a-dependent recycling of internalized MSC-sEVs under hypoxia via enhancing the interaction between Rab11a and MSC-sEV. Based on this finding, si-RCP is loaded into MSC-sEVs using electroporation to overcome the hypoxic microenvironment of intervertebral disks. The engineered MSC-sEVs significantly inhibit the endocytic recycling process and exhibit higher delivery efficiency under hypoxia. In a rat model of intervertebral disk degeneration (IDD), the si-RCP-loaded MSC-sEVs successfully treat IDD with improved regenerative capacity compared with natural MSC-sEV. Collectively, the findings illustrate the intracellular traffic mechanism of MSC-sEVs under hypoxia and demonstrate that the therapeutic capacity of MSC-sEVs can be improved via inhibiting endocytic recycling. This modifying strategy may further facilitate the application of extracellular vesicles in hypoxic tissues.

Lead halide perovskite single crystals have attracted wide interest in the field of X-ray detection due to their excellent photophysical properties. However, their inherent toxicity and high thickness restrict their applications in flexible devices. In this paper, designing a micronanometer-scale X-ray detector based on all-inorganic lead-free CsAg 2 I 3 (CAI) single crystal microbelts (MBs) has addressed the above issues. These CAI single crystal MBs can be synthesized on various substrates with high crystal quality and excellent stability. Based on their excellent characteristics of the CAI MBs, we fabricate single CAI MB devices with an Au/CAI/Au structure, which shows not only good ultraviolet photoresponse characteristics, but also excellent X-ray detection performance. The optimized CAI photodetectors exhibit a responsivity of 23.59 mA/W, a high detectivity of 10 10 Jones, and a fast response speed. For X-ray detection performance, a sensitivity of up to 515.49 μC Gy air -1 cm -2 and a detection limit of as low as 14.65 μGy air s -1 are achieved with outstanding operation stability and excellent long-term stability. Furthermore, our devices also showed excellent applicability for X-ray imaging, which is promising for their use in X-ray detection and imaging. Finally, flexible X-ray detectors are fabricated by using thin CAI single-crystal MBs and demonstrate good flexibility under different bending radii and bending cycles. Our work shows the potential for developing highly sensitive flexible integrated micro/nano optoelectronic devices by using lead-free perovskite analogue single crystals.

Amorphous metal-organic framework ( a MOF)-based materials have attracted considerable attention as an emerging class of nanomaterials. Herein, novel microorganisms@ a MIL-125 (Ti) composites including yeast@ a MIL-125 (Ti), PCC 6803@ a MIL-125 (Ti), and Escherichia coli @ a MIL-125 (Ti) composites were respectively synthesized by self-assembling a MOFs on the microorganisms' surface. The functional groups on the microorganisms' surface induced structural defects and participated in the formation of a MIL-125 (Ti) composites. Finally, the application of microorganisms@ a MIL-125 (Ti) composites for the removal of glyphosate from aqueous solution was selected as a model reaction to illustrate their potential for environmental protection. The present method is not only economical but also has other advantages including ease of operation, environmentally friendly assay, and high adsorption. The maximum adsorption capacity of a MIL-125 (Ti) was 1096.25 mg g -1 , which was 1.74 times that of crystalline MIL-125 (Ti). Therefore, the microorganisms@ a MOFs composites will have broad application prospects in energy storage, drug delivery, catalysis, adsorbing toxic substances, sensing, encapsulating and delivering enzymes, and in other fields., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The unbalanced coagulation of blood is a life-threatening event that requires accurate and timely treatment. We introduce a user-friendly biomolecular platform based on modular RNA-DNA anticoagulant fibers programmed for reversible extracellular communication with thrombin and subsequent control of anticoagulation via a "kill-switch" mechanism that restores hemostasis. To demonstrate the potential of this reconfigurable technology, we designed and tested a set of anticoagulant fibers that carry different thrombin-binding aptamers. All fibers are immunoquiescent, as confirmed in freshly collected human peripheral blood mononuclear cells. To assess interindividual variability, the anticoagulation is confirmed in the blood of human donors from the U.S. and Brazil. The anticoagulant fibers reveal superior anticoagulant activity and prolonged renal clearance in vivo in comparison to free aptamers. Finally, we confirm the efficacy of the "kill-switch" mechanism in vivo in murine and porcine models.

Temperature is the primary factor affecting the law of coal gas desorption. When the core method is used to measure the coal seam gas content (CSGC), the temperature of the coal core sample (CCS) will increase because the heat generated by the core bit cutting and rubbing the coal is transferred to the CCS through the core tube. To solve the above problems, the temperature of the core tube wall during coring at core depths of 10, 20, and 30 m was measured by a self-designed temperature measuring device. The thermodynamic models of the core bit and the core tube during coring were established. The thermal flux of the system at different stages was inverted numerically by the dichotomy method. The reliability of the model was verified by comparing the numerical simulation results with the field measurement results. The main influencing factors during coring were studied by numerical simulations. The results show that the temperature change of the core tube wall goes through four stages: slowly rising, fast rising, slowly rising, and slowly falling, which correspond to the process of pushing the core tube, drilling the CCS, and the early stage and later stage of withdrawing the core tube, respectively. The maximum temperature of the core tube wall appears in the first 5 min of withdrawing the core tube and increases with the increase of core depth. When the core depth is 30 m, the maximum temperature of the core tube wall reaches 105.17 °C. The temperature of the measuring point at the end of drilling the CCS and the maximum temperature during coring linearly increase with the core depth, friction heat generated while pushing the core tube, and coal strength. This study can provide a basis for further research on the dynamic distribution characteristics of temperature in the CCS during coring, which is of profound significance to calculate the gas loss amount and CSGC., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Due to the spatial network structure, heavy oil has a high threshold pressure gradient when it flows through porous media, and the threshold pressure gradient plays a crucial role in the distribution of remaining oil. In previous study, the common methods to measure the threshold pressure gradient include the microflow-established differential pressure (MFEDP) method, capillary equilibrium method, and the percolation curve fitting method. In this study, a sample from the SZ36-1 oilfield was analyzed for the basic physical properties based on the comparison of the previous measurement to study the influence of mobility on the threshold pressure gradient and then an independently developed numerical simulator was established to study the effect of the threshold pressure gradient on the remaining oil distribution considering the permeability range, crude oil viscosity, well network deployment, well spacing, and fluid recovery rate. The results show that the SZ36-1 oilfield fluid belongs to Bingham fluids with yield stress and the mobility having an exponent relation to the threshold pressure gradient based on the measurement of the MFEDP method. Considering the threshold pressure gradient of heavy oil, the uneven distribution of remaining oil is intensified and the remaining oil is enriched. This study provides a reference for efficient development of heavy oil reservoirs., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)

Extracellular vesicles (EVs) are potential alternatives for mesenchymal stem cells (MSCs) in the treatment of musculoskeletal degenerative diseases, including intervertebral disc degeneration (IDD). Usually, EVs are internalized and then deliver bioactive molecules that impart phenotypic changes in recipient cells. For effective utilization of EVs in the IDD therapy, understanding the mechanism of EV uptake is of vital importance. In this study, we found that EVs delivered antioxidant proteins to protect against pyroptosis of nucleus pulposus cells (NPCs). In particular, the therapeutic effect of EVs decreased in TNF-α-treated NPCs due to the impaired caveolae-mediated endocytosis pathway. Transcriptome sequencing and functional verification revealed that caveolae associated protein 2 (Cavin-2) played an important role in the uptake process of EVs. We then constructed the Cavin-2-modified engineering EVs via the gene-editing of parental MSCs. These kinds of modified EVs presented an improved uptake rate in TNF-α-treated NPCs, which effectively ameliorated the cell death of NPCs in a three-dimensional hydrogel culture model and retarded the progression of IDD in the ex vivo organ culture model. Collectively, these findings illustrate the mechanism of EV uptake in NPCs and explore the application of engineering EVs in the treatment of IDD.

Thorium as a potential nuclear fuel for the next-generation thorium-based molten salt reactors holds significant environmental and economic promise over the current uranium-based nuclear reactors. However, because thorium (Th 4+ ) usually coexists with other rare earth elements, alkali or alkaline earth metals in minerals, or highly acidic radioactive waste, seeking acid-resistant sorbents with excellent selectivity, high capacity, and fast removal rate for Th 4+ is still a challenging task. In this work, we investigated a robust layered metal sulfide (KInSn 2 S 6 , KMS-5) for Th 4+ removal from strong acidic solutions. We report that KMS-5 could capture Th 4+ from a 0.1 M HNO 3 solution with extremely high efficiency (∼99.9%), fast sorption kinetics (equilibrium time < 10 min), and large distribution coefficient (up to 1.5 × 10 6 mL/g). Furthermore, KMS-5 exhibited excellent sorption selectivity towards Th 4+ in the presence of large amounts of competitive metal ions like Eu 3+ , Na + , and Ca 2+ . This extraordinary capture property for Th 4+ is attributed to the facile ion exchange of Th 4+ with K + in the interlayers and subsequent formation of a stable coordination complex via Th-S bonds. These results indicate that KMS-5 is a promising functional sorbent for the effective capture of Th 4+ from highly acidic solutions.

The surface of a tight reservoir appears to be oil-wet or mixed-type wet upon soaking in crude oil for a long time, and the yield decreases rapidly after fracturing under the influence of capillary force. The oil sweep efficiency affected by many factors such as formation water dilution, salinity, crude oil type, temperature, and pressure can be enhanced by adding nanosurfactants into the fracturing fluid, so it is necessary to study the influence of different factors on the spontaneous imbibition replacement efficiency of nanosurfactants. In this study, the basic properties of nanosurfactants such as particle size, oil-water interfacial tension (IFT), and the wetting modification effect were tested, and the influence of surfactant type, concentration, temperature, and pressure on imbibition replacement efficiency was studied. The main conclusions are as follows: (1) The particle size of the nanosurfactant that was synthesized by a microemulsion method is 12-21 nm, which indicated good injectability in tight cores. Moreover, the IFT values between the crude oil and five kinds of 0.30 wt % nanosurfactants were all lower than 0.15 mN/m, and nanosurfactant C had the best wetting modification effect with increasing the contact angle by 100.30°. (2) The type and concentration of surfactant have a certain influence on imbibition replacement efficiency, and appropriate concentration of anionic nanosurfactant is beneficial to enhancing the imbibition replacement efficiency. The imbibition replacement efficiency of 0.30 wt % anionic surfactant C solution is higher than that of nonionic and cationic surfactant solutions, and the imbibition replacement efficiency is as high as 33.386% under NTP . (3) The nanosurfactant in brine is prone to forming fine emulsified oil droplets with crude oil and activates the oil droplets in the small pores to enhance the imbibition replacement efficiency. The crude oil type, temperature, and pressure can influence imbibition replacement efficiency, and the influence of crude oil type and temperature is greater than that of pressure. This work further studies the influencing factors of imbibition replacement efficiency., Competing Interests: The authors declare no competing financial interest., (© 2021 The Authors. Published by American Chemical Society.)

Hybrid halide perovskites consisting of corner-sharing metal halide octahedra and small cuboctahedral cages filled with counter cations have proven to be prominent candidates for many high-performance optoelectronic devices. The stability limits of their three-dimensional perovskite framework are defined by the size range of the cations present in the cages of the structure. In some cases, the stability of the perovskite-type structure can be extended even when the counterions violate the size and shape requirements, as is the case in the so-called "hollow" perovskites. In this work, we engineered a new family of 3D highly defective yet crystalline "hollow" bromide perovskites with general formula (FA) 1- x ( en ) x (Pb) 1-0.7 x (Br) 3-0.4 x (FA = formamidinium (FA + ), en = ethylenediammonium ( en 2+ ), x = 0-0.44). Pair distribution function analysis shed light on the local structural coherence, revealing a wide distribution of Pb-Pb distances in the crystal structure as a consequence of the Pb/Br-deficient nature and en inclusion in the lattice. By manipulating the number of Pb/Br vacancies, we finely tune the optical properties of the pristine FAPbBr 3 by blue shifting the band gap from 2.20 to 2.60 eV for the x = 0.42 en sample. A most unexpected outcome was that at x > 0.33 en incorporation, the material exhibits strong broad light emission (1% photoluminescence quantum yield (PLQY)) that is maintained after exposure to air for more than a year. This is the first example of strong broad light emission from a 3D hybrid halide perovskite, demonstrating that meticulous defect engineering is an excellent tool for customizing the optical properties of these semiconductors.

Development of high-efficiency non-precious metal-based electrocatalysts to drive the complex four-electron process of the oxygen evolution reaction (OER) is crucial for production of hydrogen and energy storage components. Herein, bimetallic CuCo 2 S 4 nanosheets were created by a new molecular precursor route. The optimal CuCo 2 S 4 catalyst demonstrates superior performance to catalyze the OER with excellent stability, which was confirmed by the low overpotential of 290 mV at 10 mA cm -2 in 1 M KOH. The catalytic activity can be maintained for at least 40 h. The catalyst after the OER was then detected. The results indicate that S-doped CoOOH/CuO nanosheets formed on the catalyst surface during the OER may act as the catalytic active substance. Furthermore, when employed as an air cathode in a Zn-air battery, it reveals a high open-cycle potential of 1.38 V and a peak power density of 123.9 mW cm -2 . The performance of the rechargeable Zn-air battery is close to that fabricated with commercial precious metal-based electrocatalysts. These findings would furnish some guidelines for the design, development, and applications of bimetallic sulfide electrocatalysts for the OER.

A chemical approach to the deposition of thin films on solid surfaces is highly desirable but prone to affect the final properties of the film. To better understand the origin of these complications, the initial stages of the atomic layer deposition of titania films on silica mesoporous materials were characterized. Adsorption-desorption measurements indicated that the films grow in a layer-by-layer fashion, as desired, but initially exhibit surprisingly low densities, about one-quarter of that of bulk titanium oxide. Electron microscopy, X-ray diffraction, UV/visible, and X-ray absorption spectroscopy data pointed to the amorphous nature of the first monolayers, and EXAFS and 29 Si CP/MAS NMR results to an initial growth via the formation of individual tetrahedral Ti-oxide units on isolated Si-OH surface groups with unusually long Ti-O bonds. Density functional theory calculations were used to propose a mechanism where the film growth starts at the nucleation centers to form an open 2D structure.

The advent of the two-dimensional (2D) family of halide perovskites and their demonstration in 2D/three-dimensional (3D) hierarchical film structures broke new ground toward high device performance and good stability. The 2D Dion-Jacobson (DJ) phase halide perovskites are especially attractive in solar cells because of their superior charge transport properties. Here, we report on 2D DJ phase perovskites using a 3-(aminomethyl)piperidinium (3AMP) organic spacer for the fabrication of mixed Pb/Sn-based perovskites, exhibiting a narrow bandgap of 1.27 eV and a long carrier lifetime of 657.7 ns. Consequently, solar cells employing mixed 2D DJ 3AMP-based and 3D MA 0.5 FA 0.5 Pb 0.5 Sn 0.5 I 3 (MA = methylammonium, FA = formamidinium) perovskite composites as light absorbers achieve enhanced efficiency and stability, giving a power conversion efficiency of 20.09% with a high open-circuit voltage of 0.88 V, a fill factor of 79.74%, and a short-circuit current density of 28.63 mA cm -2 . The results provide an effective strategy to improve the performance of single-junction narrow-bandgap solar cells and, potentially, to give a highly efficient alternative to bottom solar cells in tandem devices.

The optical and light emission properties of tin and lead halide perovskites are remarkable because of the robust room-temperature (RT) performance, broad wavelength tunability, high efficiency, and good quenching resistance to defects. These highly desirable attributes promise to transform current light-emitting devices, phosphors, and lasers. One disadvantage in most of these materials is the sensitivity to moisture. Here, we report a new air-stable one-dimensional (1D) hybrid lead-free halide material (DAO)Sn 2 I 6 (DAO, 1,8-octyldiammonium) that is resistant to water for more than 15 h. The material exhibits a sharp optical absorption edge at 2.70 eV and a strong broad orange light emission centered at 634 nm, with a full width at half-maximum (fwhm) of 142 nm (0.44 eV). The emission has a long photoluminescence (PL) lifetime of 582 ns, while the intensity is constant over a very broad temperature range (145-415 K) with a photoluminescence quantum yield (PLQY) of at least 20.3% at RT. Above 415 K the material undergoes a structural phase transition from monoclinic ( C 2/ c ) to orthorhombic ( Ibam) accompanied by a red shift in the band gap and a quench in the photoluminescence emission. Density functional theory calculations support the trend in the optical properties and the 1D electronic nature of the structure, where the calculated carrier effective masses along the inorganic chain are significantly lower than those perpendicular to the chain. Thin films of the compound readily fabricated from solutions exhibit the same optical properties, but with improved PLQY of 36%, for a 60 nm thick film, among the highest reported for lead-free low-dimensional 2D and 1D perovskites and metal halides.

Large organic A cations cannot stabilize the 3D perovskite AMX 3 structure because they cannot be accommodated in the cubo-octhedral cage (do not follow the Goldschmidt tolerance factor rule), and they generally template low-dimensional structures. Here we report that the large dication aminomethylpyridinium (AMPY) can template novel 3D structures which resemble conventional perovskites. They have the formula ( x AMPY)M 2 I 6 ( x = 3 or 4, M = Sn 2+ or Pb 2+ ) which is double of the AMX 3 formula. However, because of the steric requirement of the Goldschmidt tolerance factor rule, it is impossible for ( x AMPY)M 2 I 6 to form proper perovskite structures. Instead, a combination of corner-sharing and edge-sharing connectivity is adopted in these compounds leading to the new 3D structures. DFT calculations reveal that the compounds are indirect band gap semiconductors with direct band gaps presenting at slightly higher energies and dispersive electronic bands. The indirect band gaps of the Sn and Pb compounds are ∼1.7 and 2.0 eV, respectively, which is slightly higher than the corresponding AMI 3 3D perovskites. The Raman spectra for the compounds are diffuse, with a broad rising central peak at very low frequencies around 0 cm -1 , a feature that is characteristic of dynamical lattices, high anharmonicity, and dissipative vibrations very similar to the 3D AMX 3 perovskites. Devices of (3AMPY)Pb 2 I 6 crystals exhibit clear photoresponse under ambient light without applied bias, reflecting a high carrier mobility (μ) and long carrier lifetime (τ). The devices also exhibit sizable X-ray generated photocurrent with a high μτ product of ∼1.2 × 10 -4 cm 2 /V and an X-ray sensitivity of 207 μC·Gy -1 ·cm -2 .

A remarkable hallmark of cancer cells is the heterogeneous coexistence of overproduced intracellular glutathione (GSH) and a high level of reactive oxygen species (ROS) compared with those in normal cells, which have been frequently used as the stimuli to trigger drug release from the nanocarriers. Most of the stimuli-responsive delivery vehicles have been designed to respond to only one redox stimulus (e.g., GSH or ROS). Herein, we develop a GSH and ROS dual-responsive amphiphilic diblock copolymer prodrug (BCP) (GR-BCP) consisting of poly(ethylene glycol) (PEG)- and camptothecin (CPT)-conjugated poly(methacrylate) in the side chains via thioether bonds. In comparison, GSH or ROS single-responsive BCPs (G-BCPs or R-BCPs) were prepared, where CPT drugs were linked by disulfide or thioketal bonds, respectively. The three BCPs can form well-defined spherical micellar nanoparticles in an aqueous solution with a diameter of ∼50 nm. Compared with G-BCP and R-BCP, GR-BCP realized the highest cytotoxicity against HeLa cells with the half-inhibitory concentration (IC 50 ) of 6.3 μM, which is much lower than 17.8 μM for G-BCP and 28.9 μM for R-BCP. Moreover, for in vivo antitumor performance, G-BCP, R-BCP, and GR-BCP showed similar efficiencies in blood circulation and tumor accumulation after intravenous injection. However, GR-BCP realized the most efficient tumor suppression with few side effects. Our findings demonstrate that intracellular GSH and ROS dual-responsive BCPs show a more efficient responsive drug release inside tumor cells for boosting the antitumor efficacy as compared with GSH or ROS single-responsive BCPs, which provides novel strategies for designing redox-responsive BCPs.

Nucleic acids play a central role in all domains of life, either as genetic blueprints or as regulators of various biochemical pathways. The chemical makeup of ribonucleic acid (RNA) or deoxyribonucleic acid (DNA), generally represented by a sequence of four monomers, also provides precise instructions for folding and higher-order assembly of these biopolymers that, in turn, dictate biological functions. The sequence-based specific 3D structures of nucleic acids led to the development of the directed evolution of oligonucleotides, SELEX (systematic evolution of ligands by exponential enrichment), against a chosen target molecule. Among the variety of functions, selected oligonucleotides named aptamers also allow targeting of cell-specific receptors with antibody-like precision and can deliver functional RNAs without a transfection agent. The advancements in the field of customizable nucleic acid nanoparticles (NANPs) opened avenues for the design of nanoassemblies utilizing aptamers for triggering or blocking cell signaling pathways or using aptamer-receptor combinations to activate therapeutic functionalities. A recent selection of fluorescent aptamers enables real-time tracking of NANP formation and interactions. The aptamers are anticipated to contribute to the future development of technologies, enabling an efficient assembly of functional NANPs in mammalian cells or in vivo . These research topics are of top importance for the field of therapeutic nucleic acid nanotechnology with the promises to scale up mass production of NANPs suitable for biomedical applications, to control the intracellular organization of biological materials to enhance the efficiency of biochemical pathways, and to enhance the therapeutic potential of NANP-based therapeutics while minimizing undesired side effects and toxicities.

The co-decomposition of non-noble metals into Ru nanoparticles (NPs) would provide multiple active centers as well as synergistically alter the reaction pathway, enhancing the catalytic hydrogenation performance. Herein, a facile route for synthesizing trielement Ru-Ni-Fe alloy NPs was proposed. The catalytic hydrogenation performance of NPs was measured using p -nitrophenol as a model. The synergistic effect of these three elements (Ru, Ni, and Fe) and synergistic catalysis of multiple crystal faces greatly improved the catalytic hydrogenation performance of Ru 44 Ni 28 Fe 28 alloy NPs. Ru with more vacant orbitals showed a strong coordination with BH 4 - for the generation of active H species. Ni played a major role in transporting electrons and active H species, increasing the accessibility of catalytically active sites. Fe could cooperate with BH 4 - to produce active H species and promote electrons transfer. Ru 44 Ni 28 Fe 28 alloy NPs could be reused and applied for the fabrication of films at the oil-water (ethyl acetate-water) interface. The densely packed Ru 44 Ni 28 Fe 28 NP films were good Raman substrates for monitoring the complete conversion of 4-nitrothiophenol into 4-aminothiophenol. The rational design of Ru 44 Ni 28 Fe 28 will broaden the application range of Ru-based catalysts and provide new insights into the rational design of other multisite alloy catalysts.

The sensitive detection of biomarker with high selectivity and accuracy is of remarkable significance for the early screening and clinical diagnosis of malignant cancer. Persistent phosphors play a role in illumination-free biosensing owing to their unparalleled optical properties, which produces long-lasting luminescence without the illumination to eliminate the interference of autofluorescence and scattering light from biological matrix. In this study, ZnGeO:Mo persistent luminescence nanorods (PLNRs) were prepared and showed tunable luminescence intensity and decay patterns. An excitation-free luminescent aptasensor was proposed for the detection of prostate specific antigen (PSA) by using ZnGeO:Mo PLNRs as probes and Au@Ag@SiO 2 nanoparticles as quenchers. Under optimal conditions, the limit of detection for PSA was 9.2 pg mL -1 . This work creates a possibility for the preparation of multiplex colored persistent luminescence nanomaterials with desired decay patterns for multiple bioassay and time-resolved fluoroimmunoassay.

Ochratoxin A (OTA), a toxic mycotoxin, poses severe risks to environment and human health. Herein, we develop a ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods for the sensitive and reproducible quantitative detection of OTA. Au-Ag Janus nanoparticles (NPs) are successfully synthesized under the guidance of 2-mercaptobenzoimidazole-5-carboxylic acid (MBIA), which possesses intrinsic Raman signals, thus no additional modification with a Raman reporter on NPs is required. In addition, Au-Ag Janus NPs exhibit amplified and stable SERS activity. MXenes nanosheets generate a unique and stable Raman signal, making them an ideal IS for quantitative Raman analysis. In principle, Au-Ag Janus NPs are assembled with MXenes nanosheets depending on hydrogen bond and the chelation interaction between MXenes nanosheets and OTA aptamers. In the presence of OTA, Au-Ag Janus NPs are dissociated from MXenes nanosheets due to the formation of aptamer/OTA complex, leading to the attenuation of Raman signal of Au-Ag Janus NPs, and meanwhile, the signal of MXenes nanosheets remain constant. Quantitatively, upon correction by the IS Raman signals, sensitive and quantitative detection can be achieved with the limit of detection (LOD) of 1.28 pM for OTA. Our results suggest that this ratiometric SERS aptasensor is a powerful tool which shows great promise for applications in complex systems.

In situ modulation of the surface properties on the micellar drug delivery nanocarriers offers an efficient method to improve the drug delivery efficiency into cells while maintaining stealth and stability during blood circulation. Light has been demonstrated to be a temporally and spatially controllable tool to improve cellular internalization of nanoparticles. Herein, we develop reactive oxygen species (ROS)-responsive mixed polymeric micelles with photoinduced exposure of cell-penetrating moieties via photodynamic ROS production, which can facilitate cellular internalization of paclitaxel (PTX) and chlorin e6 (Ce6)-coloaded micelles for the synergistic effect of photodynamic and chemotherapy. The thioketal-bond-linked block polymers poly(ε-caprolactone)-TL-poly( N , N -dimethylacrylamide) (PCL-TL-PDMA) with a long PDMA block are used to self-assemble into mixed micelles with PCL- b -poly(2-guanidinoethyl methacrylate) (PCL-PGEMA) consisting of a short PGEMA block, which are further used to coencapsulate PTX and Ce6. After intravenous injection, prolonged blood circulation of the micelles guarantees high tumor accumulation. Upon irradiation by 660 nm light, ROS production of the micelles by Ce6 induces cleavage of PDMA to expose PGEMA shells for significantly improved cellular internalization. The combination of photodynamic therapy and chemotherapy inside the tumor cells achieves improved antitumor efficacy. The design of ROS-responsive mixed polymeric nanocarriers represents a novel and efficient approach to realize both long blood circulation and high-efficiency cellular internalization for combined photodynamic and chemotherapy under light irradiation.

Two-dimensional (2D) halide perovskites have extraordinary optoelectronic properties and structural tunability. Among them, the Dion-Jacobson phases with the inorganic layers stacking exactly on top of each other are less explored. Herein, we present the new series of 2D Dion-Jacobson halide perovskites, which adopt the general formula of A'A n -1 Pb n I 3 n +1 (A' = 4-(aminomethyl)pyridinium (4AMPY), A = methylammonium (MA), n = 1-4). By modifying the position of the CH 2 NH 3 + group from 4AMPY to 3AMPY (3AMPY = 3-(aminomethyl)pyridinium), the stacking of the inorganic layers changes from exactly eclipsed to slightly offset. The perovskite octahedra tilts are also different between the two series, with the 3AMPY series exhibiting smaller bandgaps than the 4AMPY series. Compared to the aliphatic cation of the same size (AMP = (aminomethyl)piperidinium), the aromatic spacers increase the rigidity of the cation, reduce the interlayer spacing, and decrease the dielectric mismatch between inorganic layer and the organic spacer, showing the indirect but powerful influence of the organic cations on the structure and consequently on the optical properties of the perovskite materials. All A'A n -1 Pb n I 3 n +1 compounds exhibit strong photoluminescence (PL) at room temperature. Preliminary solar cell devices based on the n = 4 perovskites as absorbers of both series exhibit promising performances, with a champion power conversion efficiency (PCE) of 9.20% for (3AMPY)(MA) 3 Pb 4 I 13 -based devices, which is higher than the (4AMPY)(MA) 3 Pb 4 I 13 and the corresponding aliphatic analogue (3AMP)(MA) 3 Pb 4 I 13 -based ones.

Establishing a simple and accurate assay for detecting Microcystin-LR (MC-LR) is of significant important for the environment and human health. Herein, we develop a ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on internal standard (IS) methods for the sensitive and reproducible quantitative detection of MC-LR. Gap-tethered SERS-active Au@AgAu nanoparticles (NPs) are successfully prepared and the gap sizes are adjustable by simply adjusting the acidity. Gap-tethered Au@AgAu NPs exhibit gap-tunable amplified SERS activity and are served as SERS tags. The graphene oxide (GO)/Fe 3 O 4 NPs demonstrate a unique and stable Raman band from the graphitic component, making them an ideal IS for quantitative Raman analysis. In principle, Au@gap@AgAu NPs are assembled with GO/Fe 3 O 4 NPs depending on the π-π stacking interaction between GO and MC-LR aptamers. In the presence of MC-LR, Au@gap@AgAu NPs are dissociated from GO/Fe 3 O 4 NPs due to the affinity of aptamer, leading to the changes of Raman intensity of SERS tags. Quantitatively, upon correction by the IS Raman signals, the limit of detection (LOD) is as low as 9.82 pM for MC-LR. The developed protocol provides a simple and rapid approach for the sensitive and quantitative detection of MC-LR and shows great promise for applications in complex systems.

The power conversion efficiency (PCE) of halide perovskite solar cells is now comparable to that of commercial solar cells. These solar cells are generally based on multication mixed-halide perovskite absorbers with nonideal band gaps of 1.5-1.6 eV. The PCE should be able to rise further if the solar cells could use narrower-band gap absorbers (1.2-1.4 eV). Reducing the Pb content of the semiconductors without sacrificing performance is also a significant driver in the perovskite solar cell research. Here, we demonstrate that mixed Pb/Sn-based perovskites containing the oversized ethylenediammonium ( en) dication, { en}FA 0.5 MA 0.5 Sn 0.5 Pb 0.5 I 3 (FA = formamidinium, MA = methylammonium), can exhibit ideal band gaps of 1.27-1.38 eV, suitable for the assembly of single-junction solar cells with higher efficiencies. The use of en dication creates a three-dimensional (3D) hollow inorganic perovskite structure, which was verified through crystal density measurements and single-crystal X-ray diffraction structural analysis as well as nuclear magnetic resonance measurements. The { en}FA 0.5 MA 0.5 Sn 0.5 Pb 0.5 I 3 structure has massive Pb/Sn vacancies and much higher chemical stability than the same structure without en and vacancies. This new property reduces the dark current and carrier trap density and increases the carrier lifetime of the Pb/Sn-based perovskite films. Therefore, solar cells using { en}FA 0.5 MA 0.5 Sn 0.5 Pb 0.5 I 3 light absorbers have substantially enhanced air stability and around 20% improvement in efficiency. After overlaying a thin MABr top layer, we found that the {5% en}FA 0.5 MA 0.5 Sn 0.5 Pb 0.5 I 3 material gives an optimized PCE of 17.04%. The results highlight the strong promise of 3D hollow mixed Pb/Sn perovskites in achieving ideal band gap materials with higher chemical stability and lower Pb content for high-performance single-junction solar cells or multijunction solar cells serving as bottom cells.

The unique hybrid nature of 2D Ruddlesden-Popper (R-P) perovskites has bestowed upon them not only tunability of their electronic properties but also high-performance electronic devices with improved environmental stability as compared to their 3D analogs. However, there is limited information about their inherent heat, light, and air stability and how different parameters such as the inorganic layer number and length of organic spacer molecule affect stability. To gain deeper understanding on the matter we have expanded the family of 2D R-P perovskites, by utilizing pentylamine (PA) 2 (MA) n-1 Pb n I 3 n+1 ( n = 1-5, PA = CH 3 (CH 2 ) 4 NH 3 + , C5) and hexylamine (HA) 2 (MA) n-1 Pb n I 3 n+1 ( n = 1-4, HA = CH 3 (CH 2 ) 5 NH 3 + , C6) as the organic spacer molecules between the inorganic slabs, creating two new series of layered materials, for up to n = 5 and 4 layers, respectively. The resulting compounds were extensively characterized through a combination of physical and spectroscopic methods, including single crystal X-ray analysis. High resolution powder X-ray diffraction studies using synchrotron radiation shed light for the first time to the phase transitions of the higher layer 2D R-P perovskites. The increase in the length of the organic spacer molecules did not affect their optical properties; however, it has a pronounced effect on the air, heat, and light stability of the fabricated thin films. An extensive study of heat, light, and air stability with and without encapsulation revealed that specific compounds can be air stable (relative humidity (RH) = 20-80% ± 5%) for more than 450 days, while heat and light stability in air can be exponentially increased by encapsulating the corresponding films. Evaluation of the out-of-plane mechanical properties of the corresponding materials showed that their soft and flexible nature can be compared to current commercially available polymer substrates (e.g., PMMA), rendering them suitable for fabricating flexible and wearable electronic devices.

Therapeutic nanoreactors are of increasing interest in precise cancer therapy, which have been explored to in situ produce therapeutic compounds from inert prodrugs or intrinsic molecules at the target sites. However, engineering a nanoreactor with tumor activable cascade reactions for efficient cooperative cancer therapy remains a great challenge. Herein, we demonstrate a polymersome nanoreactor with tumor acidity-responsive membrane permeability to activate cascade reactions for orchestrated cooperative cancer treatment. The nanoreactors are constructed from responsive polyprodrug polymersomes incorporating ultrasmall iron oxide nanoparticles and glucose oxidase in the membranes and inner aqueous cavities, respectively. The cascade reactions including glucose consumption to generate H 2 O 2 , accelerated iron ion release, Fenton reaction between H 2 O 2 and iron ion to produce hydroxyl radicals (•OH), and •OH-triggered rapid release of parent drugs can be specifically activated by the tumor acidity-responsive membrane permeability. During this process, the orchestrated cooperative cancer therapy including starving therapy, chemodynamic therapy, and chemotherapy is realized for high-efficiency tumor suppression by the in situ consumed and produced compounds. The nanoreactor design with tumor-activable cascade reactions represents an insightful paradigm for precise cooperative cancer therapy.

The two-dimensional (2D) perovskites stabilized by alternating cations in the interlayer space (ACI) define a new type of structure with different physical properties than the more common Ruddlesden-Popper counterparts. However, there is a lack of understanding of material crystallization in films and its influence on the morphological/optoelectronic properties and the final photovoltaic devices. Herein, we undertake in situ studies of the solidification process for ACI 2D perovskite (GA)(MA) n Pb n I 3 n+1 (⟨ n⟩ = 3) from ink to solid-state semiconductor, using solvent mixture of DMSO:DMF (1:10 v/v) as the solvent and link this behavior to solar cell devices. The in situ grazing-incidence X-ray scattering (GIWAXS) analysis reveals a complex journey through disordered sol-gel precursors, intermediate phases, and ultimately to ACI perovskites. The intermediate phases, including a crystalline solvate compound and the 2D GA 2 PbI 4 perovskite, provide a scaffold for the growth of the ACI perovskites during thermal annealing. We identify 2D GA 2 PbI 4 to be the key intermediate phase, which is strongly influenced by the deposition technique and determines the formation of the 1D GAPbI 3 byproducts and the distribution of various n phases of ACI perovskites in the final films. We also confirm the presence of internal charge transfer between different n phases through transient absorption spectroscopy. The high quality ACI perovskite films deposited from solvent mixture of DMSO:DMF (1:10 v/v) deliver a record power conversion efficiency of 14.7% in planar solar cells and significantly enhanced long-term stability of devices in contrast to the 3D MAPbI 3 counterpart.

A simple magnetic electrochemical aptasensor was established for the detection of prostatic specific antigen (PSA). Ag/CdO nanoparticles (NPs) were fabricated and exhibited strong electroreduction peaks at -1.07 V, attributing to the electron transfer from Cd 2+ to Cd 0 and the superior electron transportation of Ag. Aptamer-modified Ag/CdO NPs were assembled on the surface of superparamagnetic Fe 3 O 4 /graphene oxide nanosheets (GO/Fe 3 O 4 NSs) through the hydrophobic and π-π stacking interaction of aptamers and GO NSs. These assemblies possessed superior electroactive properties, efficient electron transfer, and superparamagnetic response and could serve as sensing units for PSA detection with the aid of a magnetic electrode. With increasing concentrations of PSA, the high affinity of aptamers to PSA enabled the dissociation of Ag/CdO NPs from GO/Fe 3 O 4 NSs, decreasing the intensity of electroreduction peaks. The Ag/CdO NP-engineered magnetic electrochemical aptasensor achieved sensitive and accurate detection of PSA in the range of 50 pg/mL to 50 ng/mL. The limit of detection (LOD) was as low as 28 pg/mL. This developed protocol can be extended to a large set of strong electroactive labels for reliable tumor biomarker detection with high sensitivity and specificity.

Tin dioxide (SnO 2 ) as an efficient electron transport layer (ETL) has been demonstrated for emerging high-performance organic-inorganic hybrid perovskite solar cells (PSCs). However, the low-temperature solution-processed SnO 2 usually results in high trap-state density and current-voltage hysteresis. Here, we reported an effective strategy to solve this problem by incorporating graphene ink into the low-temperature processed SnO 2 for planar structure PSCs. The electron extraction efficiency has been significantly improved with graphene-doped SnO 2 ETL coupled with attenuated charge recombination at the ETL/perovskite interface. The power conversion efficiency (PCE) of PSCs based on the graphene-SnO 2 ETL reached over 18% with negligible hysteresis. Incorporation of graphene into the ETL layer also enhanced the device stability retaining 90% of the initial PCE value after storing in ambient condition with a relative humidity of 40 ± 5% for 300 h. Our results provide an important insight into further efficiency boost in SnO 2 -based low-temperature processed PSCs.

Low-dimensional halide perovskites have recently attracted intense interest as alternatives to the three-dimensional (3D) perovskites because of their greater tunability and higher environmental stability. Herein, we present the new homologous 2D series (NH 3 C m H 2 m NH 3 )(CH 3 NH 3 ) n-1 Pb n I 3 n+1 ( m = 4-9; n = 1-4), where m represents the carbon-chain number and n equals layer-thickness number. Multilayer ( n > 1) 2D perovskites incorporating diammonium cations were successfully synthesized by the solid-state grinding method for m = 4 and 6 and by the solution method for m = 7-9. Structural characterization by single-crystal X-ray diffraction for the m = 8 and m = 9 series ( n = 1-4) reveals that these compounds adopt the Cc space group for even n members and Pc for odd n members. The optical bandgaps are 2.15 eV for two-layer ( n = 2), 2.01 eV for three-layer ( n = 3), and 1.90 eV for four-layer ( n = 4). The materials exhibit excellent solution processability, and casting thin-films of the n = 3 members was successfully accomplished. The films show a clear tendency for the higher- m members to have preferred orientation on the glass substrate, with m = 8 exhibiting almost perfect vertical layer orientation and m = 9 displaying both vertical and parallel layer orientation, as confirmed by grazing-incidence wide-angle X-ray scattering (GIWAXS) measurements. The vertical layer orientation for the (NH 3 C 8 H 16 NH 3 )(CH 3 NH 3 ) 2 Pb 3 I 10 member results in the best thermal, light, and air stability within this series, thus showing excellent potential for solar cell applications.

Relative to normal cells, tumor cells lack adequate capability of reactive oxygen scavenging. Thus, tumor cells can be selectively killed by increasing the concentration of reactive oxygen species in tumor tissue. In this report, we construct an integrated multifunctional polymeric nanoparticle which can selectively improve hydrogen peroxide (H 2 O 2 ) levels in tumor tissue and convert them into more active hydroxyl radicals by Fenton reaction. First, the diblock copolymers containing polyethylene glycol (PEG) and poly(glutamic acid) modified by β-cyclodextrin (β-CD) were synthesized. The block copolymer, ferrocenecarboxylic acid hexadecyl ester (DFc), and ascorbyl palmitate (PA) were coassembled in aqueous solution to obtain stable core-shell micelles through the inclusion complexation between β-CD moieties in the block copolymer and ferrocene (Fc) groups from DFc. After intravenous injection, the particles achieved significant accumulation in tumor tissue where ascorbic acid at the pharmacological concentration promotes the production of H 2 O 2 , and subsequently Fenton reaction was catalyzed by Fc groups to produce hydroxyl radicals to efficiently kill cancer cells and suppress tumor growth. The micellar systems possess great potentials toward cancer therapy through synergistic H 2 O 2 production and conversion into hydroxyl radicals specifically in tumor tissue.

The newly introduced class of 3D halide perovskites, termed "hollow" perovskites, has been recently demonstrated as light absorbing semiconductor materials for fabricating lead-free perovskite solar cells with enhanced efficiency and superior stability. Hollow perovskites derive from three-dimensional (3D) AMX 3 perovskites ( A = methylammonium (MA), formamidinium (FA); M = Sn, Pb; X = Cl, Br, I), where small molecules such as ethylenediammonium cations ( en) can be incorporated as the dication without altering the structure dimensionality. We present in this work the inherent structural properties of the hollow perovskites and expand this class of materials to the Pb-based analogues. Through a combination of physical and spectroscopic methods (XRD, gas pycnometry, 1 H NMR, TGA, SEM/EDX), we have assigned the general formula (A) 1- x ( en) x (M) 1-0.7 x (X) 3-0.4 x to the hollow perovskites. The incorporation of en in the 3D perovskite structure leads to massive M and X vacancies in the 3D [ MX 3 ] framework, thus the term hollow. The resulting materials are semiconductors with significantly blue-shifted direct band gaps from 1.25 to 1.51 eV for Sn-based perovskites and from 1.53 to 2.1 eV for the Pb-based analogues. The increased structural disorder and hollow nature were validated by single crystal X-ray diffraction analysis as well as pair distribution function (PDF) analysis. Density functional theory (DFT) calculations support the experimental trends and suggest that the observed widening of the band gap is attributed to the massive M and X vacancies, which create a less connected 3D hollow structure. The resulting materials have superior air stability, where in the case of Sn-based hollow perovskites it exceeds two orders of temporal magnitude compared to the conventional full perovskites of MASnI 3 and FASnI 3 . The hollow perovskite compounds pose as a new platform of promising light absorbers that can be utilized in single junction or tandem solar cells.

The three-dimensional hybrid organic-inorganic perovskites have shown huge potential for use in solar cells and other optoelectronic devices. Although these materials are under intense investigation, derivative materials with lower dimensionality are emerging, offering higher tunability of physical properties and new capabilities. Here, we present two new series of hybrid two-dimensional (2D) perovskites that adopt the Dion-Jacobson (DJ) structure type, which are the first complete homologous series reported in halide perovskite chemistry. Lead iodide DJ perovskites adopt a general formula A'A n-1 Pb n I 3 n+1 (A' = 3-(aminomethyl)piperidinium (3AMP) or 4-(aminomethyl)piperidinium (4AMP), A = methylammonium (MA)). These materials have layered structures where the stacking of inorganic layers is unique as they lay exactly on top of another. With a slightly different position of the functional group in the templating cation 3AMP and 4AMP, the as-formed DJ perovskites show different optical properties, with the 3AMP series having smaller band gaps than the 4AMP series. Analysis on the crystal structures and density functional theory (DFT) calculations suggest that the origin of the systematic band gap shift is the strong but indirect influence of the organic cation on the inorganic framework. Fabrication of photovoltaic devices utilizing these materials as light absorbers reveals that (3AMP)(MA) 3 Pb 4 I 13 has the best power conversion efficiency (PCE) of 7.32%, which is much higher than that of the corresponding (4AMP)(MA) 3 Pb 4 I 13 .

Developing dopant-free hole transporting layers (HTLs) is critical in achieving high-performance and robust state-of-the-art perovskite photovoltaics, especially for the air-sensitive tin-based perovskite systems. The commonly used HTLs require hygroscopic dopants and additives for optimal performance, which adds extra cost to manufacturing and limits long-term device stability. Here we demonstrate the use of a novel tetrakis-triphenylamine (TPE) small molecule prepared by a facile synthetic route as a superior dopant-free HTL for lead-free tin-based perovskite solar cells. The best-performing tin iodide perovskite cells employing the novel mixed-cation ethylenediammonium/formamidinium with the dopant-free TPE HTL achieve a power conversion efficiency as high as 7.23%, ascribed to the HTL's suitable band alignment and excellent hole extraction/collection properties. This efficiency is one of the highest reported so far for tin halide perovskite systems, highlighting potential application of TPE HTL material in low-cost high-performance tin-based perovskite solar cells.

Therapeutic nanoreactors have been proposed to treat cancers through in situ transformation of low-toxicity prodrugs into toxic therapeutics in the body. However, the in vivo applications are limited by low tissue-specificity and different tissue distributions between sequentially injected nanoreactors and prodrugs. Herein, we construct a block copolymer prodrug-based polymersome nanoreactor that can achieve novel orchestrated oxidation/chemotherapy of cancer via specific activation at tumor sites. The block copolymers composed of poly(ethylene glycol) (PEG) and copolymerized monomers of camptothecin (CPT) and piperidine-modified methacrylate [P(CPTMA-co-PEMA)] were optimized to self-assemble into polymersomes in aqueous solution for encapsulation of glucose oxidase (GOD) to obtain GOD-loaded polymersome nanoreactors (GOD@PCPT-NR). GOD@PCPT-NR maintained inactive in normal tissues upon systemic administration. After deposition in tumor tissues, tumor acidity-triggered protonation of PPEMA segments resulted in high permeability of the polymersome membranes and oxidation reaction of diffused glucose and O 2 under the catalysis of GOD. The activation of the reaction generated H 2 O 2 , improving the oxidative stress in tumors. Simultaneously, a high level of H 2 O 2 further activated PCPTMA prodrugs, releasing active CPT drugs. High tumor oxidative stress and released CPT drugs synergistically killed cancer cells and suppressed tumor growth via oxidation/chemotherapy. Our study provides a new strategy for engineering therapeutic nanoreactors in an orchestrated fashion for cancer therapy.

Electron-selective layers (ESLs) and hole-selective layers (HSLs) are critical in high-efficiency organic-inorganic lead halide perovskite (PS) solar cells for charge-carrier transport, separation, and collection. We developed a procedure to assess the quality of the ESL/PS junction by measuring potential distribution on the cross section of SnO 2 -based PS solar cells using Kelvin probe force microscopy. Using the potential profiling, we compared three types of cells made of different ESLs but otherwise having an identical device structure: (1) cells with PS deposited directly on bare fluorine-doped SnO 2 (FTO)-coated glass; (2) cells with an intrinsic SnO 2 thin layer on the top of FTO as an effective ESL; and (3) cells with the SnO 2 ESL and adding a self-assembled monolayer (SAM) of fullerene. The results reveal two major potential drops or electric fields at the ESL/PS and PS/HSL interfaces. The electric-field ratio between the ESL/PS and PS/HSL interfaces increased in devices as follows: FTO < SnO 2 -ESL < SnO 2 + SAM; this sequence explains the improvements of the fill factor (FF) and open-circuit voltage (V oc ). The improvement of the FF from the FTO to SnO 2 -ESL cells may result from the reduction in voltage loss at the PS/HSL back interface and the improvement of V oc from the prevention of hole recombination at the ESL/PS front interface. The further improvements with adding an SAM is caused by the defect passivation at the ESL/PS interface, and hence, improvement of the junction quality. These nanoelectrical findings suggest possibilities for improving the device performance by further optimizing the SnO 2 -based ESL material quality and the ESL/PS interface.

Tin-based perovskites have very comparable electronic properties to lead-based perovskites and are regarded as possible lower toxicity alternates for solar cell applications. However, the efficiency of tin-based perovskite solar cells is still low and they exhibit poor air stability. Here, we report lead-free tin-based solar cells with greatly enhanced performance and stability using so-called "hollow" ethylenediammonium and methylammonium tin iodide ({en}MASnI 3 ) perovskite as absorbers. Our results show that en can improve the film morphology and most importantly can serve as a new cation to be incorporated into the 3D MASnI 3 lattice. When the cation of en becomes part of the 3D structure, a high density of SnI 2 vacancies is created resulting in larger band gap, larger unit cell volume, lower trap-state density, and much longer carrier lifetime compared to classical MASnI 3 . The best-performing {en}MASnI 3 solar cell has achieved a high efficiency of 6.63% with an open circuit voltage of 428.67 mV, a short-circuit current density of 24.28 mA cm -2 , and a fill factor of 63.72%. Moreover, the {en}MASnI 3 device shows much better air stability than the neat MASnI 3 device. Comparable performance is also achieved for cesium tin iodide solar cells with en loading, demonstrating the broad scope of this approach.

The improved antioxidant system of cancer cells renders them well-adaptive to the intrinsic oxidative stress in tumor tissues. On the other hand, cancer cells are more sensitive to elevated tumor oxidative stress as compared with normal cells due to their deficient reactive oxygen species-eliminating systems. Oxidation therapy of cancers refers to the strategy of killing cancer cells through selectively increasing the oxidative stress in tumor tissues. In this article, to amplify the oxidation therapy, we develop integrated nanoparticles with the properties to elevate tumor oxidative stress and concurrently suppress the antioxidative capability of cancer cells. The amphiphilic block copolymer micelles of poly(ethylene glycol)-b-poly[2-((((4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)benzyl)oxy)carbonyl)oxy)ethyl methacrylate] (PEG-b-PBEMA) are integrated with palmitoyl ascorbate (PA) to form hybrid micelles (PA-Micelle). PA molecules at pharmacologic concentrations serve as a prooxidant to upregulate the hydrogen peroxide (H 2 O 2 ) level in tumor sites and the PBEMA segment exhibits H 2 O 2 -triggered release of quinone methide for glutathione depletion to suppress the antioxidative capability of cancer cells, which synergistically and selectively kill cancer cells for tumor growth suppression. Given the significantly low side toxicity against normal tissues, this novel integrated nanoparticle design represents a novel class of nanomedicine systems for high-efficiency oxidation therapy with the potentials to be translated to clinical applications.

The amphiphilic block copolymer anticancer drug nanocarriers clinically used or in the progress of clinical trials frequently suffer from modest final therapeutic efficacy due to a lack of intelligent features. For example, the biodegradable amphiphilic block copolymer, poly(ethylene glycol)-b-poly(d,l-lactide) (PEG-PDLLA) has been approved for clinical applications as a paclitaxel (PTX) nanocarrier (Genexol-PM) due to the optimized pharmacokinetics and biodistribution; however, a lack of intelligent features limits the intracellular delivery in tumor tissue. To endow the mediocre polymer with smart properties via a safe and facile method, we introduced a matrix metalloproteinase (MMP)-responsive peptide GPLGVRGDG into the block copolymer via efficient click chemistry and ring-opening polymerization to prepare PEG-GPLGVRGDG-PDLLA (P1). P1 was further self-assembled into micellar nanoparticles (NPs) to load PTX, which show MMP-2-triggered dePEGylation due to cleavage of the peptide linkage. Moreover, the residual VRGDG sequences are retained on the surface of the NPs after dePEGylation, which can serve as ligands to facilitate the cellular uptake. The cytotoxicity of PTX loaded in P1 NPs against 4T1 cells is significantly enhanced as compared with free PTX or PTX-loaded PEG-GPLGVRG-PDLLA (P2) and PEG-PDLLA (P3) NPs. In vivo studies confirmed that PTX-loaded P1 NPs show prolonged blood circulation, which are similar to P2 and P3 NPs but exhibit more-efficient accumulation in the tumor site. Ultimately, PTX-loaded P1 NPs display statistically significant improvement of antitumor activity against tumor-bearing mice via systemic administration. Therefore, the strategy by facile incorporation of a responsive peptide linkage between PEG and PDLLA is a promising approach to improving the therapeutic efficacy of anticancer-drug-loaded amphiphilic block copolymer micelles.

Smart nanocarriers attract considerable interest in the filed of precision nanomedicine. Dynamic control of the interaction between nanocarriers and cells offers the feasibility that in situ activates cellular internalization at the targeting sites. Herein, we demonstrate a novel class of enzyme-responsive asymmetric polymeric vesicles self-assembled from matrix metalloproteinase (MMP)-cleavable peptide-linked triblock copolymer, poly(ethylene glycol)-GPLGVRG-b-poly(ε-caprolactone)-b-poly(3-guanidinopropyl methacrylamide) (PEG-GPLGVRG-PCL-PGPMA), in which the cell-penetrating PGPMA segments asymmetrically distribute in the outer and inner shells with fractions of 9% and 91%, respectively. Upon treatment with MMP-2 to cleave the stealthy PEG shell, the vesicles undergo morphological transformation into fused multicavity vesicles and small nanoparticles, accompanied by redistribution of PGPMA segments with 76% exposed to the outside. The vesicles after dePEGylation show significantly increased cellular internalization efficiency (∼10 times) as compared to the original ones due to the triggered availability of cell-penetrating shells. The vesicles loading hydrophobic anticancer drug paclitaxel (PTX) in the membrane exhibit significantly enhanced cytotoxicity against MMP-overexpressing HT1080 cells and multicellular spheroids. The proposed vesicular system can serve as a smart nanoplatform for in situ activating intracellular drug delivery in MMP-enriched tumors.

Radiosensitizer plays an important role in the cancer radiotherapy for efficient killing of hypoxic cancer cells at a low radiation dose. However, the commercially available small molecular radiosensitizers show low efficiency due to poor bioavailability in tumor tissues. In this report, we develop a novel amphiphilic block copolymer radiosensitizer, metronidazole-conjugated poly(ethylene glycol)- b -poly(γ-propargyl-l-glutamate) (PEG- b -P(PLG- g -MN)), which can be self-assembled into core-shell micelles (MN-Micelle) with an optimal size of ∼60 nm in aqueous solution. In vitro cytotoxicity evaluation indicated that MN-Micelle sensitized the hypoxic cancer cells more efficiently under radiation with the sensitization enhancement ratio (SER) of 1.62 as compared with that of commercially available sodium glycididazole (GS; SER = 1.17) at the metronidazole-equivalent concentration of 180 μg/mL. Upon intravenous injection of MN-Micelle into the tumor-bearing mice, high tumor deposition was achieved, which finally suppressed tumor growth completely after electron beam radiation at a low radiation dose of 4 Gy. MN-Micelle with outstanding performance as an in vivo radiosensitizer holds great potentials for translation into radiotherapy application.

There have been significant advancements in electric vehicles (EVs) in recent years. However, the different changing patterns in emissions at upstream and on-road stages and complex atmospheric chemistry of pollutants lead to uncertainty in the air quality benefits from fleet electrification. This study considers the Yangtze River Delta (YRD) region in China to investigate whether EVs can improve future air quality. The Community Multiscale Air Quality model enhanced by the two-dimensional volatility basis set module is applied to simulate the temporally, spatially, and chemically resolved changes in PM 2.5 concentrations and the changes of other pollutants from fleet electrification. A probable scenario (Scenario EV1) with 20% of private light-duty passenger vehicles and 80% of commercial passenger vehicles (e.g., taxis and buses) electrified can reduce average PM 2.5 concentrations by 0.4 to 1.1 μg m -3 during four representative months for all urban areas of YRD in 2030. The seasonal distinctions of the air quality impacts with respect to concentration reductions in key aerosol components are also identified. For example, the PM 2.5 reduction in January is mainly attributed to the nitrate reduction, whereas the secondary organic aerosol reduction is another essential contributor in August. EVs can also effectively assist in mitigating NO 2 concentrations, which would gain greater reductions for traffic-dense urban areas (e.g., Shanghai). This paper reveals that the fleet electrification in the YRD region could generally play a positive role in improving regional and urban air quality.

Achieving high open-circuit voltage (V oc ) for tin-based perovskite solar cells is challenging. Here, we demonstrate that a ZnS interfacial layer can improve the V oc and photovoltaic performance of formamidinium tin iodide (FASnI 3 ) perovskite solar cells. The TiO 2 -ZnS electron transporting layer (ETL) with cascade conduction band structure can effectively reduce the interfacial charge recombination and facilitate electron transfer. Our best-performing FASnI 3 perovskite solar cell using the cascaded TiO 2 -ZnS ETL has achieved a power conversion efficiency of 5.27%, with a higher V oc of 0.380 V, a short-circuit current density of 23.09 mA cm -2 , and a fill factor of 60.01%. The cascade structure is further validated with a TiO 2 -CdS ETL. Our results suggest a new approach for further improving the performance of tin-based perovskite solar cells with a higher V oc .