Nanoarchitectonics of S-Scheme Heterojunction Photocatalysts: A Nanohouse Design Improves Photocatalytic Nitrate Reduction to Ammonia Performance.

Photocatalytic nitrate reduction reaction (NitRR) is a promising route for environment remediation and sustainable ammonia synthesis. To design efficient photocatalysts, the recently emerged nanoarchitectonics approach holds great promise. Here, we report a nanohouse-like S-scheme heterjunction photocatalyst with high photocatalytic NitRR performance. The nano-house has a floor of plate-like metal organic framework-based photocatalyst (NH2-MIL-125), on which another photocatalyst Co(OH)2 nanosheet is grown while ZIF-8 hollow cages are also constructed as the surrounding wall/roof. Experimental and simulation results indicate that the positively charged, highly porous and hydrophobic ZIF-8 wall can modulate the environment in the nanohouse by (i) NO3- enrichment / NH4+ discharge and (ii) suppression of the competitive hydrogen evolution reaction. In combination with the enhanced electron-hole separation and strong redox capability in the NH2-MIL-125@Co(OH)2 S-scheme heterjunction confined in the nano-house, the designed photocatalyst delivers an ammonia yield of 2454.9 µmol g-1 h-1 and an apparent quantum yield of 8.02% at 400 nm in pure water. Our work provides new insights into the design principles of advanced photocatalytic NitRR photocatalyst.

Enabling Logistics Automation in Nanofactory: Cobalt Phosphide Embedded Metal-Organic Frameworks for Efficient Electrocatalytic Nitrate Reduction to Ammonia.

Electrocatalytic nitrate reduction reaction (NitRR) in neutral condition offers a promising strategy for green ammonia synthesis and wastewater treatment, the rational design of electrocatalysts is the cornerstone. Inspired by modern factory design where both machines and logistics matter for manufacturing, it is reported that cobalt phosphide (CoP) nanoparticles embedded in zinc-based zeolite imidazole frameworks (Zn-ZIF) function as a nanofactory with high performance. By selective phosphorization of ZnCo bimetallic zeolite imidazole framework (ZnCo-ZIF), the generated CoP nanoparticles act as "machines" (active sites) for molecular manufacturing (NO3 - to NH4 + conversion). The purposely retained framework (Zn-ZIFs) with positive charge promotes logistics automation, i.e., the automatic delivery of NO3 - reactants and timely discharge of NH4 + products in-and-out the nanofactory due to electrostatic interaction. Moreover, the interaction between Zn-ZIF and CoP modulates the Co sites into electron insufficient state with upshifted d-band center, facilitating the reduction/hydrogenation of NO3 - to ammonia and restricting the competitive hydrogen evolution. Consequently, the assembled CoP/Zn-ZIF nanofactory exhibits superior NitRR performances with a high Faraday efficiency of ≈97% and a high ammonia yield of 0.89 mmol cm-1 h-1 in neutral condition, among the best of reported electrocatalysts. The work provides new insights into the design principles of efficient NitRR electrocatalysts.

Highly efficient nitrogen fixation over S-scheme heterojunction photocatalysts with enhanced active hydrogen supply.

Photocatalytic N2 fixation is a promising strategy for ammonia (NH3) synthesis; however, it suffers from relatively low ammonia yield due to the difficulty in the design of photocatalysts with both high charge transfer efficiency and desirable N2 adsorption/activation capability. Herein, an S-scheme CoSx/ZnS heterojunction with dual active sites is designed as an efficient N2 fixation photocatalyst. The CoSx/ZnS heterojunction exhibits a unique pocket-like nanostructure with small ZnS nanocrystals adhered on a single-hole CoSx hollow dodecahedron. Within the heterojunction, the electronic interaction between ZnS and CoSx creates electron-deficient Zn sites with enhanced N2 chemisorption and electron-sufficient Co sites with active hydrogen supply for N2 hydrogenation, cooperatively reducing the energy barrier for N2 activation. In combination with the promoted photogenerated electron-hole separation of the S-scheme heterojunction and facilitated mass transfer by the pocket-like nanostructure, an excellent N2 fixation performance with a high NH3 yield of 1175.37 µmol g-1 h-1 is achieved. This study provides new insights into the design of heterojunction photocatalysts for N2 fixation.

A Pioglitazone Nanoformulation Designed for Cancer-Associated Fibroblast Reprogramming and Cancer Treatment.

The recent focus of cancer therapeutics research revolves around modulating the immunosuppressive tumor microenvironment (TME) to enhance efficacy. The tumor stroma, primarily composed of cancer-associated fibroblasts (CAFs), poses significant obstacles to therapeutic penetration, influencing resistance and tumor progression. Reprogramming CAFs into an inactivated state has emerged as a promising strategy, necessitating innovative approaches. This study pioneers the design of a nanoformulation using pioglitazone, a Food and Drug Administration-approved anti-diabetic drug, to reprogram CAFs in the breast cancer TME. Glutathione (GSH)-responsive dendritic mesoporous organosilica nanoparticles loaded with pioglitazone (DMON-P) are designed for the delivery of cargo to the GSH-rich cytosol of CAFs. DMON-P facilitates pioglitazone-mediated CAF reprogramming, enhancing the penetration of doxorubicin (Dox), a therapeutic drug. Treatment with DMON-P results in the downregulation of CAF biomarkers and inhibits tumor growth through the effective delivery of Dox. This innovative approach holds promise as an alternative strategy for enhancing therapeutic outcomes in CAF-abundant tumors, particularly in breast cancer.

Doping Regulation Stabilizing δ-MnO2 Cathode for High-Performance Aqueous Aluminium-ion Batteries.

δ-MnO2 is a promising cathode material for aqueous aluminium-ion batteries (AAIBs) for its layered crystalline structure with large interlayer spacing. However, the excellent Al ion storage performance of δ-MnO2 cathode remains elusive due to the frustrating structural collapse during the intercalation of high ionic potential Al ion species. Here, it is discovered that introducing heterogeneous metal dopants with high bond dissociation energy when bonded to oxygen can significantly reinforce the structural stability of δ-MnO2 frameworks. This reinforcement translates to stable cycling properties and high specific capacity in AAIBs. Vanadium-doped δ-MnO2 (V-δ-MnO2 ) can deliver a high specific capacity of 518 mAh g-1 at 200 mA g-1 with remarkable cycling stability for 400 cycles and improved rate capabilities (468, 339, and 285 mAh g-1 at 0.5, 1, and 2 A g-1 , respectively), outperforming other doped δ-MnO2 materials and the reported AAIB cathodes. Theoretical and experimental studies indicate that V doping can substantially improve the cohesive energy of δ-MnO2 lattices, enhance their interaction with Al ion species, and increase electrical conductivity, collectively contributing to high ion storage performance. These findings provide inspiration for the development of high-performance cathodes for battery applications.

Robust Covalent Organic Framework Photocatalysts for H2O2 Production: Linkage Position Matters.

Covalent organic frameworks (COFs) are promising photocatalysts for hydrogen peroxide (H2O2) synthesis. However, the nature of organic polymers makes the balance between high activity and stability challenging. We demonstrate that the linkage position matters in the design of robust COF photocatalysts with durable high activity without sacrificial reagents. COFs with ortho- and para-linkages (o-COFs and p-COFs) were constructed by 1,3,5-triformylphloroglucinol with benzene-, pyridine-, pyrazine-orthodiamines and paradiamines. The pyrzaine-containing o-COFs with two pyridinic nitrogen atoms exhibited a H2O2 production rate of 4396 µmol g-1 h-1 together with long-time continuous H2O2 photosynthesis performance in pure water (48 h), superior to the corresponding p-COFs. A four-step reaction mechanism is proposed by density function calculations. Moreover, the active sites and origin of stability enhancement for o-COFs are clarified. This work provides a simple and effective molecular design strategy in the design of robust COF photocatalysts for artificial H2O2 photosynthesis.

Mesoporous nanoperforators as membranolytic agents via nano- and molecular-scale multi-patterning.

Plasma membrane lysis is an effective anticancer strategy, which mostly relying on soluble molecular membranolytic agents. However, nanomaterial-based membranolytic agents has been largely unexplored. Herein, we introduce a mesoporous membranolytic nanoperforators (MLNPs) via a nano- and molecular-scale multi-patterning strategy, featuring a spiky surface topography (nanoscale patterning) and molecular-level periodicity in the spikes with a benzene-bridged organosilica composition (molecular-scale patterning), which cooperatively endow an intrinsic membranolytic activity. Computational modelling reveals a nanospike-mediated multivalent perforation behaviour, i.e., multiple spikes induce nonlinearly enlarged membrane pores compared to a single spike, and that benzene groups aligned parallelly to a phospholipid molecule show considerably higher binding energy than other alignments, underpinning the importance of molecular ordering in phospholipid extraction for membranolysis. Finally, the antitumour activity of MLNPs is demonstrated in female Balb/c mouse models. This work demonstrates assembly of organosilica based bioactive nanostructures, enabling new understandings on nano-/molecular patterns co-governed nano-bio interaction.

Steam activation of porous concave polymer nanospheres for high-efficient chromium and cadmium removal.

The issue of heavy metal contamination in water is a global concern, and the development of highly efficient adsorbent materials is crucial for the removal and detoxification of heavy metals. Polymer-based materials have emerged as a promising class of adsorbents due to their ability to capture heavy metal pollutants and reduce them to less toxic forms. The limited surface area of conventional polymer adsorbents makes them less effective for high-capacity adsorption. Herein, we present a low-temperature steam activation approach to address this challenge. This activation approach leads to a remarkable increase of over 20 times in the surface area of concave aminophenol-formaldehyde (APF) polymer nanospheres (from 45 to 961 m2/g) while preserving their reductive functional groups. The activated concave APF nanospheres were evaluated for their adsorption capabilities towards two typical heavy metal ions (i.e., Cr(VI) and Cd(II)) in aqueous solutions. The maximum adsorption capacities achieved were 1054 mg g-1 for Cr(VI) and 342 mg g-1 for Cd(II), which are among the highest performances reported in the literature and are much higher than the capacities of the non-activated APF nanospheres. Additionally, approximately 71.5 % of Cr(VI) was simultaneously reduced to Cr(III) through the benzenoid amine pathway during adsorption, highlighting the crucial role of the steam activation strategy in enhancing the capability of polymer adsorbents.

High-efficiency Electroreduction of O2 into H2 O2 over ZnCo Bimetallic Triazole Frameworks Promoted by Ligand Activation.

Co-based metal-organic frameworks (MOFs) as electrocatalysts for two-electron oxygen reduction reaction (2e- ORR) are highly promising for H2 O2 production, but suffer from the intrinsic activity-selectivity trade-off. Herein, we report a ZnCo bimetal-triazole framework (ZnCo-MTF) as high-efficiency 2e- ORR electrocatalysts. The experimental and theoretical results demonstrate that the coordination between 1,2,3-triazole and Co increases the antibonding-orbital occupancy on the Co-N bond, promoting the activation of Co center. Besides, the adjacent Zn-Co sites on 1,2,3-triazole enable an asymmetric "side-on" adsorption mode of O2 , favoring the reduction of O2 molecules and desorption of OOH* intermediate. By virtue of the unique ligand effect, the ZnCo-MTF exhibits a 2e- ORR selectivity of ≈100 %, onset potential of 0.614 V and H2 O2 production rate of 5.55 mol gcat -1 h-1 , superior to the state-of-the-art zeolite imidazole frameworks. Our work paves the way for the design of 2e- ORR electrocatalysts with desirable coordination and electronic structure.

Engineered Silica Nanoparticles for Nucleic Acid Delivery.

The development of nucleic acid-based drugs holds great promise for therapeutic applications, but their effective delivery into cells is hindered by poor cellular membrane permeability and inherent instability. To overcome these challenges, delivery vehicles are required to protect and deliver nucleic acids efficiently. Silica nanoparticles (SiNPs) have emerged as promising nanovectors and recently bioregulators for gene delivery due to their unique advantages. In this review, a summary of recent advancements in the design of SiNPs for nucleic acid delivery and their applications is provided, mainly according to the specific type of nucleic acids. First, the structural characteristics and working mechanisms of various types of nucleic acids are introduced and classified according to their functions. Subsequently, for each nucleic acid type, the use of SiNPs for enhancing delivery performance and their biomedical applications are summarized. The tailored design of SiNPs for selected type of nucleic acid delivery will be highlighted considering the characteristics of nucleic acids. Lastly, the limitations in current research and personal perspectives on future directions in this field are presented. It is expected this opportune review will provide insights into a burgeoning research area for the development of next-generation SiNP-based nucleic acid delivery systems.

Mesoporous silica/organosilica nanoparticles for cancer immunotherapy.

Cancer is one of the fatal diseases in the history of humankind. In this regard, cancer immunotherapeutic strategies have revolutionized the traditional mode of cancer treatment. Silica based nano-platforms have been extensively applied in nanomedicine including cancer immunotherapy. Mesoporous silica nanoparticles (MSN) and mesoporous organosilica nanoparticles (MON) are attractive candidates due to the ease in controlling the structural parameters as needed for the targeted immunotherapeutic applications. Especially, the MON provide an additional advantage of controlling the composition and modulating the biological functions to actively synergize with other immunotherapeutic strategies. In this review, the applications of MSN, MON, and metal-doped MSN/MON in the field of cancer immunotherapy and tumor microenvironment regulation are comprehensively summarized by highlighting the structural and compositional attributes of the silica-based nanoplatforms.

Engineering Crystallinity Gradients for Tailored CaO2 Nanostructures: Enabling Alkalinity-Reinforced Anticancer Activity with Minimized Ca2+/H2O2 Production.

CaO2 nanoparticles (CNPs) can produce toxic Ca2+ and H2O2 under acidic pH, which accounts for their intrinsic anticancer activity but at the same time raises safety concerns upon systemic exposure. Simultaneously realizing minimized Ca2+/H2O2 production and enhanced anticancer activity poses a dilemma. Herein, we introduce a "crystallinity gradient-based selective etching" (CGSE) strategy, which is realized by creating a crystallinity gradient in a CNP formed by self-assembled nanocrystals. The nanocrystals distributed in the outer layer have a higher crystallinity and thus are chemically more robust than those distributed in the inner layer, which can be selectively etched. CGSE not only leads to CNPs with tailored single- and double-shell hollow structures and metal-doped compositions but more surprisingly enables significantly enhanced anticancer activity as well as tumor growth inhibition under limited Ca2+/H2O2 production, which is attributed to an alkalinity-reinforced lysosome-dependent cell death pathway.

Origin of Cycle Performance in the Ag2O/TiO2 Heterostructure Photocatalyst.

In recent years, many studies on photocatalysis focused on improving efficiency. However, the cycle performance is also an important index for industrialization. Here, an Ag2O/TiO2 heterostructure photocatalyst is prepared for continuous photodegradation of methylene blue (MB) under visible light, and the samples after the first and fifth round reactions are recycled to study the microstructure evolution of the photocatalyst. The results show that the performance is obviously improved in the second round and remains stable in the following reaction round. Due to the charge transfer, Ag2O/TiO2 gradually changes to Ag2O@Ag-TiO2-x during the photocatalytic reaction. The resulting localized surface plasmon resonance effect and the change of the interface structure greatly increase the number of carriers and prolong the lifetime of carriers. Such variations of microstructures and photoelectric properties of the samples due to the charge transfer and redox reaction on the surface of the photocatalyst dominate the cycle performance.

Silica nanoparticles: A review of their safety and current strategies to overcome biological barriers.

Silica nanoparticles (SNP) have gained tremendous attention in the recent decades. They have been used in many different biomedical fields including diagnosis, biosensing and drug delivery. Medical uses of SNP for anti-cancer, anti-microbial and theranostic applications are especially prominent due to their exceptional performance to deliver many different small molecules and recently biologics (mRNA, siRNA, antigens, antibodies, proteins, and peptides) at targeted sites. The physical and chemical properties of SNP such as large specific surface area, tuneable particle size and porosity, excellent biodegradability and biocompatibility make them an ideal drug delivery and diagnostic platform. Based on the available data and the pre-clinical performance of SNP, recent interest has driven these innovative materials towards clinical application with many of the formulations already in Phase I and Phase II trials. Herein, the progress of SNP in biomedical field is reviewed, and their safety aspects are analysed. Importantly, we critically evaluate the key structural characteristics of SNP to overcome different biological barriers including the blood-brain barrier (BBB), skin, tumour barrier and mucosal barrier. Future directions, potential pathways, and target areas towards rapid clinical translation of SNP are also recommended.

A hierarchical spatial assembly approach of silica-polymer composites leads to versatile silica/carbon nanoparticles.

Assembly of silica and polymer in the absence of surfactant templates is an emerging strategy to construct intricate nanostructures, whereas the underlying mechanism and structural versatility remain largely unexplored. We report a hierarchical spatial assembly strategy of silica-polymer composites to produce silica and carbon nanoparticles with unprecedented structures. The assembly hierarchy involves a higher length scale asymmetric A-B-A core-shell-type spatial assembly in a composite sphere, and a nanoscale assembly in the middle layer B in which the silica/polymer ratio governs the assembled structures of silica nanodomains. Through an in-depth understanding of the hierarchical spatial assembly mechanism, a series of silica and carbon nanoparticles with intriguing and controllable architectures are obtained that cannot be easily achieved via conventional surfactant-templating approaches. This work opens an avenue toward the designed synthesis of nanoparticles with precisely regulated structures.

Epitaxial growth of metal-organic framework nanosheets into single-crystalline orthogonal arrays.

Construction of two-dimensional nanosheets into three-dimensional regular structures facilitates the mass transfer and exploits the maximum potential of two-dimensional building blocks in applications such as catalysis. Here, we report the synthesis of metal-organic frameworks with an orthogonal nanosheet array. The assembly involves the epitaxial growth of single crystalline metal-organic framework nanosheets with a naturally non-preferred facet exposure as the shell on a cubic metal-organic framework as the core. The nanosheets, despite of two typical shapes and crystallographic orientations, also form a single crystalline orthogonally arrayed framework. The density and size of nanosheets in the core-shell-structured composite metal-organic frameworks can be well adjusted. Moreover, metal-organic frameworks with a single composition and hollow orthogonal nanosheet array morphology can be obtained. Benefiting from the unusual facet exposure and macroporous structure, the designed structure exhibits improved electrocatalytic oxygen evolution activity compared to conventional nanosheets.

Engineering nanoparticle toolkits for mRNA delivery.

The concept of using mRNA to produce its own medicine in situ in the body makes it an ideal drug candidate, holding great potential to revolutionize the way we approach medicine. The unique characteristics of mRNA, as well as its customizable biomedical functions, call for the rational design of delivery systems to protect and transport mRNA molecules. In this review, a nanoparticle toolkit is presented for the development of mRNA-based therapeutics from a drug delivery perspective. Nano-delivery systems derived from either natural systems or chemical synthesis, in the nature of organic or inorganic materials, are summarised. Delivery strategies in controlling the tissue targeting and mRNA release, as well as the role of nanoparticles in building and boosting the activity of mRNA drugs, have also been introduced. In the end, our insights into the clinical and translational development of mRNA nano-drugs are presented.

Spatial Specific Janus S-Scheme Photocatalyst with Enhanced H2 O2 Production Performance.

Photocatalytic oxygen reduction reaction (ORR) for H2 O2 production in the absence of sacrificing agents is a green approach and of great significance, where the design of photocatalysts with high performance is the central task. Herein, a spatial specific S-scheme heterojunction design by introducing a novel semiconducting pair with a S-scheme mechanism in a purpose-designed Janus core-shell-structured hollow morphology is reported. In this design, TiO2 nanocrystals are grown inside the inner wall of resorcinol-formaldehyde (RF) resin hollow nanocakes with a reverse bumpy ball morphology (TiO2 @RF). The S-scheme heterojunction preserves the high redox ability of the TiO2 and RF pair, the spatial specific Janus design enhances the charge separation, promotes active site exposure, and reduces the H2 O2 decomposition to a large extent. The TiO2 @RF photocatalyst shows a high H2 O2 yield of 66.6 mM g-1  h-1 and solar-to-chemical conversion efficiency of 1.11%, superior to another Janus structure (RF@TiO2 ) with the same heterojunction but a reversed Janus spatial arrangement, and most reported photocatalysts under similar reaction conditions. The work has paved the way toward the design of next-generation photocatalysts for green synthesis of H2 O2 production.

Mesoporous Organosilica Nanoparticles with Tetrasulphide Bond to Enhance Plasmid DNA Delivery.

Cellular delivery of plasmid DNA (pDNA) specifically into dendritic cells (DCs) has provoked wide attention in various applications. However, delivery tools that achieve effective pDNA transfection in DCs are rare. Herein, we report that tetrasulphide bridged mesoporous organosilica nanoparticles (MONs) have enhanced pDNA transfection performance in DC cell lines compared to conventional mesoporous silica nanoparticles (MSNs). The mechanism of enhanced pDNA delivery efficacy is attributed to the glutathione (GSH) depletion capability of MONs. Reduction of initially high GSH levels in DCs further increases the mammalian target of rapamycin complex 1 (mTORc1) pathway activation, enhancing translation and protein expression. The mechanism was further validated by showing that the increased transfection efficiency was apparent in high GSH cell lines but not in low GSH ones. Our findings may provide a new design principle of nano delivery systems where the pDNA delivery to DCs is important.