Spatial Confinement Effect Research Articles

2D/1D nested hollow porous ZnIn2S4/g-C3N4 heterojunction based on morphology modulation for photocatalytic CO2 reduction

The two-dimensional (2D) composite one-dimensional (1D) heterojunction structure is one of the main strategies for constructing composite photocatalysts for photocatalytic reduction of carbon dioxide (CO2). However, morphology modulation for 2D/1D heterojunction is an important way to enhance performance. In this study, a unique 2D/1D ZnIn2S4/g-C3N4 nested hollow porous heterojunction structure was constructed by an in-situ growth method with spatial confinement effect. The synergy between 1D g-C3N4 and 2D ZnIn2S4, achieved through advanced morphology modulation at an optimal ratio of 3:1, results in the formation of the CZ-3 photocatalyst. This unique configuration enables a simultaneous high yield of carbon monoxide (CO) and methane (CH4), achieving 79.96 μmol/g and 17.33 μmol/g respectively, under visible light irradiation without the need for sacrificial agents. The core of this enhanced photocatalytic performance is attributed to the employment of a type-II heterojunction mechanism, which optimizes the transfer of photogenerated carriers. Ultraviolet-visible diffuse reflection spectrum, photoluminescence spectrum and photoelectrochemical analysis reveal the effect of morphology on photocatalytic performance in terms of visible light absorption, photogenerated carrier pairs separation and electronic band structure of heterojunction. By combining the advantages of 2D/1D structural benefits with the efficient charge dynamics of a type-II heterojunction, this work provides new ideas for improving the morphology of composite heterojunction photocatalysts with 2D/1D structure to enhance the photocatalytic CO2 reduction performance.

Space confinement effect of carbon nanotube-alumina strip support on the Cu-Co catalysts for CO2 methanation

The present work reported the space confinement effect of carbon nanotube-alumina strip (CAS) support on the Cu-Co bimetallic catalyst or the single Cu, Co catalysts for the CO2 methanation. CAS, made by extrusion of nanotubes and Al-based sol and high temperature calcination, was a macroscopic support with sufficient mesopores and hydrophobic property. Cu-Co/CAS catalysts exhibited high catalytic activity for methanation of CO2 (H2/CO2=3:1), where CO2 conversion was 49.62% and CH4 selectivity was 95.98% at temperature as low as 250 ℃ and 1.5 MPa, and showed advantage significantly over those with the supports of individual nanotube or pure Alumina support. The comparison suggested the hydrophobicity of carbon nanotubes can effectively remove water from the metal active sites, enhancing the equilibrium of reverse water gas shift and CO methanation reactions, as compared to alumina support. Additionally, CAS support had a spatial confinement effect that increased the contact time of CO2 or intermediates with the active sites, compared with individual nanotube support. XPS and Raman spectroscopy validated the presence of oxygen vacancies of CAS, promoting the CO2 methanation. H2-TPR results, in combination with DFT calculations, confirmed that the CAS supports enabled the Cu-Co active phase by changing their electronic structures, to possess a strong adsorption activation capacity for H2 at low temperatures with high performance for CO2 methanation.

Spatial confinement offered by a blocker on the laser-induced breakdown spectroscopy of Ti plasma

Spatial confinement effects offered by a blocker on the laser-induced plasma parameters of titanium (Ti) are evaluated using the Optical Emission Spectroscopy technique. Nd:YAG (1064 nm, 10 ns) laser is used as an irradiation source. To observe the spatial confinement effects, an Al blocker at different distances of 4, 6, and 8 mm from the target is placed along the plume path. All the measurements are performed under the Ar environment at different pressures. It is observed that with increasing laser irradiance plasma parameters such as excitation temperature (Te) and electron number density (ne) increase, whereas it is vice versa true for increasing blocker distances. Without the blocker, the maximum values of Te and ne are about 7000 K and 1.4 × 1018 cm−3, respectively, at an Ar pressure of 50 Torr. A significant increase in emission intensity along with Te ≈ 9810 K and ne ≈ 2.2 × 1018 cm−3 is achieved in the presence of blocker. The results show that spatial confinement is responsible for the enhancement of Te and ne, which is attributed to the increased collisional frequency of plasma species after compression by shockwaves. The ablation pressure and shock pressure are also analytically evaluated and vary from 0.15 to 0.25 GPa and from 0.1 to 0.2 GPa, respectively, with increasing laser irradiance. With increasing blocker distances from 4 to 8 mm, the work done by reflected shockwaves to compress the plume varies from 0.02 to 0.002 mJ.

Spatial confinement modulates endothelial cell behavior and traction force in 3D hydrogel microgrooves

The mechanical environment of vascular endothelial cells (ECs) encompasses a wide range of curvatures due to variations in blood vessel diameters. Integrins, key mediators of cell-matrix interactions, establish connections between the extracellular matrix and the actin cytoskeleton, influencing diverse cellular behaviors. In this study, we explored the impact of spatial confinement on human umbilical vein ECs (HUVECs) cultured within three-dimensional hydrogel microgrooves of varying curvatures and the underlying role of integrins in mediating cellular responses. Employing maskless lithography, we successfully fabricated precise and wall curvatures-controlled hydrogel microgrooves, conferring spatial constraints on the cells. Our investigations revealed substantial alterations in HUVEC behavior within the hydrogel microgrooves with varying sidewall curvatures, marked by reduced cell size, enhanced orientation, and increased apoptosis. Interestingly, microgroove curvature emerged as a crucial factor influencing cell orientation and apoptosis, with rectangular microgrooves eliciting distinct changes in cell orientation, while ring-form microgrooves exhibited higher apoptosis rates. The side-wall effect in the 20 μm region near the microgroove wall had the greatest influence on cell orientation and apoptosis. HUVECs within the microgrooves exhibited elevated integrin expression, and inhibition of αV-integrin by cilengitide significantly curtailed cell apoptosis without affecting proliferation. Additionally, integrin-mediated cell traction force closely correlated with the spatial confinement effect. Cilengitide not only reduced integrin and focal adhesion expression but also attenuated cell traction force and cytoskeletal actin filament alignment. Overall, our findings elucidate the spatial confinement of ECs in hydrogel microgrooves and underscores the pivotal role of integrins, particularly αV-integrin, in mediating cell traction force and apoptosis within this microenvironment.

In-situ targeted removal of naphthalene from groundwater by peroxymonosulfate activation using molecularly imprinted activated carbon: Efficacy, mechanism and applicability

Efficient removal of low-concentration refractory polycyclic aromatic hydrocarbons (PAHs) pollutants is crucial for ensuring groundwater safety. In this study, surface molecularly imprinted catalyst (MIP@AC) was developed based on activated carbon (AC) and molecular imprinting technology, and then MIP@AC was introduced into the simulated permeable reaction barrier to evaluate the performance of MIP@AC activated peroxymonosulfate (PMS) in in-situ targeted remediation of naphthalene (NAP) contaminated groundwater. The results showed that the relative adsorption selectivity coefficient and relative degradation selectivity coefficient of the MIP@AC material relative to the non-imprinted material AC was as high as 31.47 and 10.88, respectively; that is, MIP@AC can better resist the interference of competitive pollutants and achieve efficient targeted removal of NAP. Additionally, the reactive oxygen species (ROS) yield was higher in the MIP@AC/PMS system compared to the AC/PMS system. The target pollutant NAP was precisely enriched in the imprinted cavity of the MIP@AC, realizing that ROS production and pollutant degradation occurred simultaneously in the MIP@AC imprinted cavity. Therefore, the spatial confinement effect of the imprinted cavity shortened the mass transfer distance between the ROS and NAP, thereby reducing the loss of ROS due to self-quenching. Besides, Cl- significantly promoted the targeted removal of NAP, while HCO3- had a slight inhibitory effect; humic acid had no effect because of its larger molecular structure, which does not fit into the small imprinted cavities preferred by NAP. Importantly, the MIP@AC/PMS system demonstrated effective anti-complex matrix interference ability and targeted removal performance for NAP under natural groundwater conditions. This study can promote further research on the surface molecularly imprinted catalyst/PMS system as a new strategy for in-situ targeted remediation technology of contaminated groundwater.

Spatial confinement of Co3O4 in hollow carbon sphere to boost peroxymonosulfate activation for effective degradation of organic pollutants

Herein, hollow carbon sphere (HCS) is constructed via hard template method for loading the Co3O4, and obtained catalyst (namely Co3O4/HCS) is then employed to activate peroxymonosulfate (PMS) for the removal of tetracycline (TC). Owing to high specific surface area and good conductivity of HCS, Co3O4 modified with HCS exhibits low interface resistance and fast charge transfer rate. Meanwhile, hollow structure of HCS can provide spatial confinement effect for Co3O4 and accelerate the mass transfer process between Co3O4 and PMS. As predicted, peroxy bond break of PMS over Co3O4/HCS is significantly boosted compared with pure Co3O4, so reaction system can produce more SO4•–, OH•, 1O2 and high-valent metal complexes to conduct TC degradation. Importantly, Co3O4/HCS-mediated electron transfer process between PMS and TC is also involved in TC degradation. As a result, Co3O4/HCS shows excellent performance in TC degradation, and the highest removal efficiency of TC is more than 95 % within 10 min. Benefiting from the protective effect of HCS, only a small amount of Co ion is released from Co3O4/HCS during the reaction process. Besides, Co3O4/HCS possesses good reusability and anti-interference ability. In short, current work provides a promising catalyst for PMS activation to treat wastewater containing antibiotic.

Logic Signal Amplification System for Sensitive Electrochemiluminescence Detection and Subtype Identification of Cancer Cells.

Achieving sensitive detection and accurate identification of cancer cells is vital for diagnosing and treating the disease. Here, we developed a logic signal amplification system using DNA tetrahedron-mediated three-dimensional (3D) DNA nanonetworks for sensitive electrochemiluminescence (ECL) detection and subtype identification of cancer cells. Specially designed hairpins were integrated into DNA tetrahedral nanostructures (DTNs) to perform a catalytic hairpin assembly (CHA) reaction in the presence of target microRNA, forming hyperbranched 3D nanonetworks. Benefiting from the "spatial confinement effect," the DNA tetrahedron-mediated catalytic hairpin assembly (DTCHA) reaction displayed significantly faster kinetics and greater cycle conversion efficiency than traditional CHA. The resulting 3D nanonetworks could load a large amount of Ru(phen)32+, significantly enhancing its ECL signal, and exhibit detection limits for both miR-21 and miR-141 at the femtomolar level. The biosensor based on modular logic gates facilitated the distinction and quantification of cancer cells and normal cells based on miR-21 levels, combined with miR-141 levels, to further identify different subtypes of breast cancer cells. Overall, this study provides potential applications in miRNA-related clinical diagnostics.

Ordered porous copper sulfide with hollow interior for superior electrochemical CO2 to formate conversion

Targeted for superior formate production from electrochemical carbon dioxide (CO2) reduction, hollow ordered porous copper sulfide cuboctahedra (HOP CuS-CO) with controlled shell thicknesses were designed and synthesized in this study. Uniform and interconnected pores are evenly distributed in the hollow shells of HOP CuS-CO. Capitalizing on the merits of porous cages, HOP CuS-CO exhibit outstanding formate production with a Faradaic efficiency up to 70.3 % and catalytic stability of 26 h under an applied potential of −1.1 V versus reversible hydrogen electrode (vs. RHE). In situ Raman spectroscopy results reveal that the adsorption of HCOO* intermediates is promoted on the catalyst surfaces of HOP CuS-CO due to a spatial confinement effect, which leads to highly efficient CO2 to formate conversion. The present study offers insights for designing materials toward superior formate production from electrochemical CO2 reduction.

Diamine‐Assistant Synthesis of Cu@MFI Catalysts for Ethanol Dehydrogenation

AbstractEncapsulation of metal particles into zeolites is an attractive strategy for stabilizing metal species. Nevertheless, most metal cations tend to precipitate under basic and hydrothermal conditions without the use of effective anchoring agents. Herein, low‐cost diamines of ethylenediamine and propanediamine were selected as effective chelators, which stabilized the Cu species under basic conditions and then anchored them into the framework of MFI (silicate‐1) during the hydrothermal process. The obtained Cu@MFI−R catalyst showed >96 % ethanol conversion and 98 % acetaldehyde selectivity in the 300 h time on stream, demonstrating superior advantages over the impregnation method prepared Cu/MFI catalysts. Characterization of Cu@MFI−R catalysts revealed that Cu nanoparticles were fixed in the framework of MFI, producing abundant Cu+ species for ethanol conversion. Additionally, the spatial confinement effects inhibited Cu+ reduction and aggregations, affording a high catalyst stability. Differently, over Cu/MFI catalysts, the unconfined Cu+ species were prone to be reduced into Cu0 during the reaction, resulting in the Cu particles aggregation and activity depression.

Efficient isomerization of glucose into fructose by MgO-doped lignin-derived ordered mesoporous carbon

The conversion of glucose into fructose can transform cellulose into high-value chemicals. This study introduces an innovative synthesis method for creating an MgO-based ordered mesoporous carbon (MgO@OMC) catalyst, aimed at the efficient isomerization of glucose into fructose. Throughout the synthesis process, lignin serves as the exclusive carbon precursor, while Mg2+ functions as both a crosslinking agent and a metallic active center. This enables a one-step synthesis of MgO@OMC via a solvent-induced evaporation self-assembly (EISA) method. The synthesized MgO@OMCs exhibit an impeccable 2D hexagonal ordered mesoporous structure, in addition to a substantial specific surface area (378.2 m2/g) and small MgO nanoparticles (1.52 nm). Furthermore, this catalyst was shown active, selective, and reusable in the isomerization of glucose to fructose. It yields 41 % fructose with a selectivity of up to 89.3 % at a significant glucose loading of 7 wt% in aqueous solution over MgO0.5@OMC-600. This performance closely rivals the current maximum glucose isomerization yield achieved with solid base catalysts. Additionally, the catalyst retains a fructose selectivity above 60 % even after 4 cycles, a feature attributable to its extended ordered mesoporous structure and the spatial confinement effect of the OMCs, bestowing it with high catalytic efficiency.

Versatile Fe3O4-impregnated catalytic ceramic membrane for effective atrazine removal: Confined catalytic oxidation processes, reactive oxygen species selectivity and performance in real wastewater

An Fe3O4-impregnated catalytic ceramic membrane (CCM) was fabricated through a facile ethylene glycol-gel-assisted wet impregnation method. Ethylene glycol played a dual role, acting as a reducing agent for iron (III) nitrate salt and a chelating agent to disperse catalyst uniformly in the CCM. The resulting 5xFe3O4-CCM efficiently activated peroxymonosulfate (PMS) to generate reactive oxygen species (ROS), achieving a 99% removal of atrazine (ATZ) within a short hydraulic retention time (HRT) of 5.7 s. This was facilitated by the spatial confinement effect in CCMs, enhancing the interaction among ATZ, ROS and CCM. The versatile 5xFe3O4-CCM could also effectively activate H2O2 and peroxydisulfate (PDS). It demonstrated robustness in real wastewater matrices (settled water and RO-reject) collected from local water reclamation and treatment plants. The 5xFe3O4-CCM exhibited self-cleaning properties in reducing fouling of CCM by humic acid. ROS scavenging experiments and electron paramagnetic resonance (EPR) spectroscopy revealed the pivotal role of SO4•-, •OH, and 1O2 in ATZ removal. The co-existing anion species HCO3- showed a strong inhibitory effect on ATZ degradation compared to other ionic species (NO3- and Cl-), attributed to different scavenging reaction rate of both SO4•- and •OH by anions in generating less reactive species. Possible degradation pathways of 5xFe3O4-CCM/PMS were proposed based on the LC-QTOF analysis, including oxidation, dealkylation, dealkylation-hydroxylation, dechlorination-hydroxylation of both s-triazine ring and side chain. The toxicity of the ATZ by-products was assessed, revealing reduced toxicity after treatment. With optimized operating parameters, Fe3O4-CCM can be utilized effectively in different advanced oxidation processes (AOPs) and real wastewater matrices.

Heteroatoms-doped hierarchically porous graphene as electrode material for supercapacitors with ultra-high capacitance

In this work, a dual-templating pyrolysis strategy is successfully developed to synthesize a highly crumpled graphene (N-TRPG-800). The achievement of the graphene is based on the carbonization of the d(+)-glucosamine hydrochloride and the spatial confinement effect of the graphitic carbon nitride (g-C3N4) in the presence of zinc nanoparticles (Zn NPs). During the pyrolysis process, the d(+)-glucosamine hydrochloride first polymerizes into the layers of g-C3N4, which is derived from melamine. Afterwards, a further increase in pyrolysis temperature leads to the decomposition of g-C3N4 and the generation of reducing NH3 gas, which eventually resulting in the formation of 2D ultrathin structure and high heteroatoms doping degree. Simultaneously, the volatilization of the Zn NPs also plays a key role in the pore formation and the hierarchical structure generation. As a result, the as-synthesized graphene sheets simultaneously possesses hierarchical porous structure, high heteroatoms-doped degree, and large specific surface area (506 m2 g−1). Electrochemical measurements show that the N-TRPG-800 exhibits an ultrahigh supercapacitance of 471 F g−1 at 0.2 A g−1 in a three-electrode mode, approaching the theoretical capacitance of 550 F g−1 of graphene, which is superior to that of the state-of-the-art heteroatom-doped porous carbons in literature.

A TiO2 nanotube photoanode (blue TiO2 nanotube/RuO2/BiVO4) for efficient acetaminophen degradation and nitrogen removal

To simultaneously remove organic carbon and nitrogen, especially from wastewater containing organic amine compounds, a nanotube photoanode was prepared by depositing RuO2 and BiVO4 nanoparticles in and on a blue TiO2 nanotube substrate (BTNT/RuO2/BiVO4). The synthesized materials were systematically characterized by scanning electron microscope, energy-dispersive X-ray, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical tests. Acetaminophen, a commonly used pharmaceutical with an amine group, was used as the model pollutant to examine the performance of the prepared electrodes. The results indicated that acetaminophen could be degraded by 100 % in 180 min over BTNT/RuO2/BiVO4 with a rate constant of 0.0338 min−1, which was 25.0 and 1.1 times higher than those obtained over BTNT/BiVO4 and BTNT/RuO2, respectively. Meanwhile, 81.3 % of total nitrogen could be removed. Compared with BTNT/BiVO4 and BTNT/RuO2, BTNT/RuO2/BiVO4 had a significant synergistic effect, and the synergy index reached to 47.7 %. Additionally, BTNT/RuO2/BiVO4 exhibited good stability, high current efficiency (63.2 %) and low energy consumption (0.020 kWh·g COD−1). The good performance of BTNT/RuO2/BiVO4 was mainly attributed to the enhanced formation of ClO· resulted from the synergistic interaction between RuO2 and BiVO4 due to the spatial confinement effect. Lastly, a possible reaction mechanism via ClO· over BTNT/RuO2/BiVO4 was proposed.

A dual-core 3D DNA nanomachine based on DNAzyme positive feedback loop for highly sensitive MicroRNA imaging in living cells

A double 3D DNA walker nanomachine by DNAzyme self-driven positive feedback loop amplification for the detection of miRNA was constructed. This method uses two gold nanoparticles as the reaction core, and because of the spatial confinement effect the local concentration of the reactants increase the collision efficiency was greatly improved. Meanwhile, the introduction of positive feedback loop promotes the conversion efficiency. In presence of miRNA-21, a large amount of DNAzyme was released and hydrolyze the reporter probe, resulting the recovery of fluorescence signal. The linear range for miRNA-21 is 0.5–60 pmol/L, and the detection limit is 0.41 pmol/L (S/N = 3). This nanomachine has been successfully used for accurate detection of miRNA-21 expression levels in cell lysates. At the same time, it can enter cells for intracellular miRNA-21 fluorescence imaging, distinguishing tumor cells from normal cells. This combination of in vitro detection and imaging analysis of living cells can achieve the goal of jointly detecting cancer markers through multiple pathways, providing new ideas for early diagnosis and screening of diseases.

MOF‐derived 1D/3D N‐doped porous carbon for spatially confined electrochemical CO2 reduction to adjustable syngas

AbstractElectrochemical reduction of CO2 to syngas (CO and H2) offers an efficient way to mitigate carbon emissions and store intermittent renewable energy in chemicals. Herein, the hierarchical one‐dimensional/three‐dimensional nitrogen‐doped porous carbon (1D/3D NPC) is prepared by carbonizing the composite of Zn‐MOF‐74 crystals in situ grown on a commercial melamine sponge (MS), for electrochemical CO2 reduction reaction (CO2RR). The 1D/3D NPC exhibits a high CO/H2 ratio (5.06) and CO yield (31 mmol g−1 h−1) at −0.55 V, which are 13.7 times and 21.4 times those of 1D porous carbon (derived from Zn‐MOF‐74) and N‐doped carbon (carbonized by MS), respectively. This is attributed to the unique spatial environment of 1D/3D NPC, which increases the adsorption capacity of CO2 and promotes electron transfer from the 3D N‐doped carbon framework to 1D carbon, improving the reaction kinetics of CO2RR. Experimental results and charge density difference plots indicate that the active site of CO2RR is the positively charged carbon atom adjacent to graphitic N on 1D carbon and the active site of HER is the pyridinic N on 1D carbon. The presence of pyridinic N and pyrrolic N reduces the number of electron transfer, decreasing the reaction kinetics and the activity of CO2RR. The CO/H2 ratio is related to the distribution of N species and the specific surface area, which are determined by the degree of spatial confinement effect. The CO/H2 ratios can be regulated by adjusting the carbonization temperature to adjust the degree of spatial confinement effect. Given the low cost of feedstock and easy strategy, 1D/3D NPC catalysts have great potential for industrial application.

Boosting photoelectrochemical water oxidation by self-assembled Co@β-cyclodextrin supramolecules modified on BiVO4 photoanode

Severe charge recombination and poor surface water oxidation kinetics are key restrictions of BiVO4 photoanode for efficient photoelectrochemical (PEC) water oxidation. In order to overcome this issue, we introduce Co@β-cyclodextrin (Co@β-CD) supramolecule as oxidation evolution catalyst (OEC) into BiVO4 photoanode for the first time via a facile two-step immersion method. The optimal Co@β-CD/BiVO4 photoanode displays a remarkable photocurrent density of 5.3 mA cm−2 at 1.23 VRHE, which is ca. 3.5 times as high as that of pristine BiVO4 photoanode. Further analyses indicate that photogenerated holes could quickly transfer from BiVO4 to Co sites through β-CD, thereby suppressing charge recombination. Moreover, due to the spatial confinement effect of β-CD, the dispersed Co sites in Co@β-CD are considered to possess the high catalytic activity in similar with single-atom catalyst, which accelerates the surface water oxidation kinetics. This work not only demonstrates the superiority of supramolecule/semiconductor composite photoanode, but also provides a facile preparation route for the large-scale preparation of high-performance photoanodes.

The confinement effect on phase change materials by physicochemical structure of wood-based materials

The impact of the three-dimensional graded porous structure and active functional groups of wood on phase change materials (PCM) is worthy of consideration. It often results in a decrease in the actual latent heat (A) of wood-based composite phase change materials (WCPCM) compared to the theoretical latent heat (T). In this study, natural balsa wood was initially chosen as the encapsulation carrier for paraffin wax (PW) and polyethylene glycol (PEG) to explore the impact of interface effects on PCM. The results demonstrate that the A/T ratio of WCPCM prepared with balsa wood and PW is 0.99, which is higher than that of WCPCM prepared with balsa wood and PEG (0.96) due to the interface confinement effects caused by hydrogen bonding. Subsequently, delignified balsa wood (LW) and hemicellulose-removal balsa wood (HW) were utilized to encapsulate PW, and the spatial confinement effects on PCM were discussed. Delignification resulted in the opening of pits. While hemicellulose removal resulted in the generation of more mesoporous structures in wood. This resulted in a specific surface area of 19.204 m2/g, which is 142.2% larger than that of LW. Both of these changes improved the permeability of balsa wood, leading to an encapsulation efficiency of 88.1% (LW) and 89.6% (HW) for PW, respectively. However, due to the spatial confinement effects of nanoscale pores, the A/T value of HW/PW (HWP) is lower (0.93) than that of PW encapsulated with LW (0.96), ultimately resulting in a lower latent heat for HWP (172.8 J/g) compared to LWP (174.8 J/g). This study provides theoretical insights into selecting PCMs and encapsulation matrices in future research.

Imaging mRNA in vitro and in vivo with nanofirecracker probes via intramolecular hybridization chain reaction

Hybridization chain reaction (HCR) based enzyme-free amplification techniques have recently been developed for the visualization of intracellular messenger RNA (mRNA). However, the slow kinetics and potential interference with the intricate biological environments hinder its application in the clinic and in vivo. Herein, we designed a nanofirecracker probe-based strategy using intramolecular hybridization chain reaction (IHCR) amplifier for rapid, efficient, sensitive, specific detection and imaging of survivin mRNA both in vitro and vivo. Two probes, HP1 and HP2, in IHCR were simultaneously incorporated into a DNA nanowire scaffolds to bring HP1 and HP2 to close proximity on the assembled nanowire scaffolds. Empowered by the DNA nanowire scaffolds and spatial confinement effect, the nanofirecracker probe-based IHCR sensing system exhibited improved biostability, accelerated reaction kinetics, and enhanced signal amplification. This new strategy has been successfully applied to imaging mRNA in both cultured cells and in mice. Importantly, this novel sensing method was capable of detecting survivin mRNA in clinical blood samples from subjects with colorectal cancer. Thus, this novel nanofirecracker probe-based IHCR strategy holds great potential in advancing both biomedical research and in molecular diagnostics.

Carbon vacancies and spatial confinement effects of VC-FCN0.3 prepared by spatial self-corrosion strategy achieved eco-friendly photocatalytic degradation to bisphenol F

The widespread use of bisphenol F (BPF) as the commonly used alternative to bisphenol A (BPA) in the industry and its hazardous effects on ecological system and human health have attracted widespread attention. In this study, VC-FCN0.3 hollow nanotube structure with confinement space effects and combined carbon vacancies was constructed by the spatial self-corrosion strategy, which effectively addressed the inherent limitations of conventional carbon nitride and achieved 100% removal rate of BPF within 2 h under visible light. Carbon vacancies not only accelerated the transfer of photogenerated carriers, but also enhanced the adsorption and activation of oxygen that accelerating the production of ·O2−, the main active species in this system. In addition, the special spatial structure shortened the mass transfer distance between the target pollutants and the active species. What's more, VC-FCN0.3 showed excellent, stable, and eco-friendly photocatalytic degradation of bisphenol F over a wide pH range and in five water matrices, contributing effectively to the solution of purification of wastewater containing bisphenol analogues.

Strong Dimensional and Structural Dependencies of Hot Carrier Effects in InGaAs Nanowires: Implications for Photovoltaic Solar Cells.

III-V nanowire structures are among the promising material systems with applications in hot carrier solar cells. These nanostructures can meet the requirements for such photovoltaic devices, i.e., the suppression of thermalization loss, an efficient hot carrier transport, and enhanced photoabsorption thanks to their unique one-dimensional (1D) geometry and density-of-states. Here, we investigate the effects of spatial confinement of photogenerated hot carriers in InGaAs-InAlAs core-shell nanowires, which presents an ideal class of hot carrier solar cell materials due to its suitable electronic properties. Using steady-state photoluminescence spectroscopy, our study reveals that by increasing the degree of spatial confinement and Auger recombination, the effects of hot carriers increase, which is in good agreement with theoretical modeling. However, for thin nanowires, the temperature of hot carriers decreases as the effects of crystal disorder increase. This observation is confirmed by probing the extent of the disorder-induced Urbach tail and linked to the presence of a higher density of stacking defects in the limit of thin nanowires. These findings expand our knowledge of hot carrier thermalization in nanowires, which can be applied for designing efficient 1D hot carrier absorbers for advanced-concept photovoltaic solar cells.