Internal Hollow Structure Research Articles

A comparison of the proto-dolomite induced by cyanobacteria and halophilic bacteria: implications for dolomite-inducing microbe identification

This study investigates the morphological and mineralogical characteristics of proto-dolomite induced by two specific microorganisms with varying lifestyles: the extremely halophilic bacterium Vibrio harveyi QPL2 and the cyanobacterium Leptolyngbya boryana. Halophilic bacterially-induced proto-dolomite (HBD) and cyanobacterially-induced proto-dolomite (CBD) were subjected to comprehensive characterization techniques, including X-ray diffraction, scanning electron microscopy, Focused Ion Beam, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The results indicate that both HBD and CBD exhibit a low degree of crystallinity and possess comparable molar ratios of MgCO3 to CaCO3. Moreover, neither of them exhibits the ordered structure of ideal dolomite. HBD and CBD exhibit notable distinctions in external morphology and internal structure. HBD forms a subunit aggregate with a less dense surface and numerous pinhole structures resulting from bacterial survival. In contrast, CBD adopts a bispherical shape with a relatively dense surface and minimal indications of cyanobacterial survival. Both HBD and CBD have an internal hollow structure. However, HBD is characterized by sparse population and loosely arranged subunits, while CBD features only a central cavity. Additionally, HBD particles are smaller compared to CBD particles. These morphological differences suggest that HBD primarily grows through bacterial surface-dependent processes, whereas the growth of CBD is not directly reliant on the surface of cyanobacteria. Compositionally, the weight percentage of crystalline water in CBD exceeded that of HBD with a value of 29.42 % compared to 5.9 %. This increase in internal crystalline water enables a faster conversion of CBD to the ordered ideal dolomite in a specific diagenetic environment. This study implies that the morphology and composition of microbial proto-dolomite may aid in identifying the type of dolomite-inducing microbes.

One-step synthesis of seamlessly contacted non-precious metal cocatalyst modified CdS hollow nanoflowers spheres for photocatalytic hydrogen production

This study ingeniously synthesized a novel CdS/NiS hollow nanoflower sphere (HNS) using a one-step method to enhance photocatalytic hydrogen production activity. Compared to conventional preparation methods, this approach features seamlessly interfaced contact that facilitates efficient electron transfer across the interface. The internal hollow structure allows for multiple light reflections, maximizing light absorption, while the exterior shell and inner surfaces simultaneously offer active sites for reactions. The modification with non-noble metal NiS enables the extraction of electrons from CdS to the NiS surface, achieving rapid charge separation. Furthermore, adsorption-free energy calculations reveal that the NiS surface is more conducive to photocatalytic hydrogen generation, providing additional reaction active sites. The results demonstrate a hydrogen production rate of 2.18 mmol g–1 h–1 for CdS/NiS HNS, which is 9.48 times greater than that of pristine CdS. This work presents a novel approach for synthesizing seamlessly interfaced contacts between photocatalysts and cocatalysts, offering new insight into efficient one-step synthesis for enhanced photocatalytic performance.

Fabrication of Tuneable Tissue-Mimicking Phantom for Optical Methods.

Tissue mimicking optical phantoms are commonly used to calibrate or validate the performance of near-infrared spectroscopy or tomography. Human tissue is not only irregular in shape, but also exhibits dynamic behaviour, which can cause changes in optical properties. However, existing phantoms lack complex structures and/or continuously varying optical properties. The project aimed to design, fabricate and characterise a novel phantom system for testing near-infrared imaging devices. We designed a dynamic tissue-mimicking phantom platform which features arbitrary internal shapes and variable optical properties. The solid part of phantom was made of silicone material with absorbing and scattering properties similar to the brain. We printed a semi-ellipsoidal sphere (a major axis=20 mmand a minor axis=the third axis=12 mm) using a water-soluble material polyvinyl alcohol (PVA). The shape was placed at the depth of 5 mm in the silicone bulk. The desired internal hollow structure was formed after curing and submerging the phantom in water. The liquid part contained dyes and Intralipid. The optical properties within the internal shape were adjusted by injecting the liquid solutions of varying dye concentrations with a syringe pump at a constant rate. The phantom was measured by a frequency domain near-infrared spectroscopy (FD NIRS) and imaged by a time domain near-infrared optical tomography (TD NIROT). A dynamic phantom system with a complex internal structure and varying optical properties was created. Changes in light intensity were detected by the FD NIRS. The internal structure of this phantom was accurately recovered by NIROT image reconstruction. We successfully developed a novel phantom system with an internal complex shape and continuously adjustable optical properties. This phantom was accurately imaged using NIROT, and the changing light intensity was detected by NIRS. It is a valuable tool for validating optical technologies.

Graphene Hollow Micropatterns via Capillarity-Driven Assembly for Drug Storage and Neural Cell Alignment.

Electrical conductivity, cell-guided surface topology, and drug storage capacity of biomaterials are attractive properties for the repair and regeneration of anisotropic tissues with electrical sensitivity, such as nerves. However, designing and fabricating implantable biomaterials with all these functions remain challenging. Herein, we developed a freestanding graphene substrate with micropatterned surfaces by a simple templating method. Importantly, the raised surface micropatterns had an internal hollow structure. The morphology results showed that the template microgroove width and the graphene nanosheet size were important indicators of the formation of the hollow structures. Through real-time monitoring and theoretical analysis of the formation process, it was found that the main formation mechanism was the delamination and interlayer movement of the graphene nanosheets triggered by the evaporation-induced capillary force. Finally, we achieved the controlled release of loaded microparticles and promoted the orientation of rat dorsal root ganglion neurons by applying an electric field to the hollow micropatterns. This capillarity-induced self-assembly strategy paves the way for the development of high-performance graphene micropatterned films with a hollow structure that have potential for clinical application in the repair of nerve injury.

Simulations on the oxidation of Al-Mg alloy nanoparticles using the ReaxFF reactive force field

Nanoalloy holds multiple complex morphologies in combustion. However, the underlying mechanism, which is crucial to advance technical application of the nanoalloy, remains a challenging mystery. Herein, we performed a ReaxFF reactive molecular dynamics simulation on Al-Mg alloy nanoparticles (AMNPs) as a case study to further analyze oxidation behavior. Results showed that the evolution of AMNPs in combustion can be divided into three stages: (1) AMNPs first undergo phase separation and aggregate into Mg and Al phases; (2) Mg atoms rapidly diffuse to the surface and are oxidized; (3) Oxygen atoms diffuse inward and oxidize Al atoms. The inward diffusion of oxygen atoms is particularly hindered at the interface between Mg oxide shell and Al oxide layer. AMNPs prefer to form internal hollow structures at lower temperature and high oxygen concentration. The outward diffusion of Mg atoms causes the core to be gradually hollowed out. The spilled Mg atoms are oxidized and attached to the surface of alumina. The structure of Mg oxide (surface layer)-Al oxide (middle layer)-hollow (core) is finally formed. In addition, micro-explosion and external Mg oxide shell inhibit the agglomeration of nanoparticles. The study provides insight into the complex interactions between Al-Mg nanoalloy and oxygen.

Morphological and physicochemical characteristics, biological functions, and biomedical applications of diatom frustule

Diatoms are the most important contributors to marine primary production, and their most distinctive feature is the silicified cell wall, known as frustule. Recent years, abundant evidences demonstrate that frustule is essential for diatoms metabolic activities, such as nutrients uptake, protection against ultraviolet radiation, deterrent to predation, resistance to parasites, light harvesting, CO2 capture, and position control. Besides that, due to the uniform composition of silica, internal hollow structure, multilayer porous valve, high thermal stability, and functionally active surface, frustule, as the most exquisite biosilica in the earth, also shows huge potentiality in biomedical field serving as promising bionanomaterials. Considering that the architecture features and physicochemical properties of frustule underlie its biological functions and biomedical applications, therefore, this review starts from the morphological and physicochemical characteristics, and then introduces the biological functions and biomedical applications of the frustule.

Self-supported hollow-Co3O4@CNT: A versatile anode and cathode host material for high-performance lithium-ion and lithium-sulfur batteries

Inferior specific capacity and sluggish redox kinetics are the most stubborn problems lithium-ion and lithium-sulfur batteries (LIBs and LSBs) are facing, respectively. Here we report a facile fabrication of self-supported hollow Co 3 O 4 @carbon nanotubes on carbon cloth (H-Co 3 O 4 @CNT/CC) through a mild pyrolysis-oxidation process. The additive- and binder-free H-Co 3 O 4 @CNT/CC shows excellent electrochemical performances as both LIBs and LSBs electrodes. As a robust integrated anode for LIBs, the areal capacities are 2.72 mAh cm −2 at the current density of 0.5 C over 1000 cycles. While as a durable cathode host for LSBs, favorable areal capacities of 2.37 mAh cm −2 are maintained with a low capacity decay of 0.11 % per cycle at the sulfur loading of 6 mg cm −2 and current density of 1 C after 400 cycles. Electrochemical technology, ex situ Raman spectroscopy and DFT calculations are performed to comprehensively analyze H-Co 3 O 4 @CNT/CC via thermodynamics and kinetics. It is demonstrated that the hierarchically hollow interior structure, strong adsorb ability of Co 3 O 4 toward polysulfides and three-dimensional (3D) inter-connected conductive carbon framework are responsible for the high areal capacity, fast redox kinetics and cycling durability. The synergistic effect of different components and structures of hollow-Co 3 O 4 @CNT, which have internal hollow structure, incorporation of Co 3 O 4 into elastic buffering framework and high porosity, contributes greatly to the superior electrochemical performances in terms of high areal capacity, good rate capability and ultralong cycling stability. • The integrated electrode possesses the merits of hollow nanostructured Co 3 O 4 and 3D inter-connected conductive network. • Electrochemical technology and DFT calculations are performed to comprehensively analyze H-Co 3 O 4 @CNT/CC. • H-Co 3 O 4 @CNT/CC delivers high areal capacities of 2.72 mAh cm -2 after 1000 cycles at 0.5 C as anode.

Electrochemical behaviors of porous spherical spinel H1.6Mn1.6O4 with high Li+ adsorption capacity

A self-assembled spherical H1.6Mn1.6O4 adsorbent with surface porous and internal hollow structure was successfully synthesized. Due to the special surface porous and internal hollow structure, the adsorbent exposes channels and interfaces for ions migration and ad/desorption, and also provides sites for charge transfer. At an initial Li+ concentration of 400 mg/L, the spherical adsorbent adsorption capacity of lithium can efficiently reach an extreme 47.54 mg/g in 360 min (the traditional adsorption route is 44.36 mg/g at 2880 min) without alkaline assistance by applying the electrochemical adsorption technique. In the multiple MCl (M = Li, Na, K, Rb, Cs) solution with each metal ion molar concentration of 14.41 mmol/L, the adsorbent adsorption capacity keeps 89.71% of a single LiCl solution. After the 5th cycle, the adsorption capacity to lithium remains at 94.98% (the traditional adsorption route is 86.65%) of the initial adsorption value. According to the analysis of cyclic voltammetry (CV) curves, it is found that the key kinetic factor limiting the adsorption rate is that the ions migration rate cannot catch up with the electrons transfer rate during the adsorption process. Furthermore, the electric field self-promotes the pH of the solution, and the corresponding alkaline environment is favorable for the adsorption behaviors. In the actual salt lakes brine, the 1st electrochemical adsorption capacity of the adsorbent for lithium is 3.26 mmol/g (Salt lake B), and the 5th adsorption capacity is 83.74% of the 1st adsorption value.

Effective adsorption and acceleration redox conversion towards lithium polysulfide by nanorod-like Sb-doped SnO2 nanofibers for high-performance lithium-sulfur battery

Lithium-sulfur batteries (LSBs) have attracted increasing attention due to high theoretical energy density and low cost of sulfur. However, there are still many challenges regarding sulfur cathodes such as the “shuttle effect” of polysulfides, insulating properties of sulfur and Li2S2/Li2S, and the sluggish redox kinetics. In this study, the nanorod-like Sb-doped SnO2 nanofibers (ATO NFs) with hollow structure were prepared by the electro-blown spinning technology and calcination processes, and used as a sulfur host for cathode materials. The internal hollow structure and the nanorod-like structure on the surface of the nanofibers with the increased specific surface area are beneficial to load sulfur and improve transport channels of electrons and lithium ions. And the hollow nanofibers also can well accommodate to huge volume changes in the reaction process. More importantly, the ATO NFs with hollow structure have good physical confinement and chemical adsorption performance to polysulfides. Based on these merits, the ATO NFs composite cathode exhibits a high initial discharge specific capacity of 765.3 mAh g−1 and maintains 550.6 mAh g−1 after 900 cycles at a rate of 2 C with 1.9 mg cm−2 sulfur loading. More importantly, high initial area discharge specific capacity of the electrode is 5.5 mAh cm−2 at 0.1 C with sulfur loading of 5.6 mg cm−2. Even, at a rate of 0.2 C, the area capacity still is stabilized at 3.5 mAh cm−2 after 100 cycles. The work illustrates that the ATO NFs for LSBs exhibit good cycling stability over a long period of time, entering the ranks of high performance and ultra-stable capacity. And it also facilitate to expand the scope of application of ATO NFs in other related energy storage fields.

Polypyrrole Modified MoS2 Nanorod Composites as Durable Pseudocapacitive Anode Materials for Sodium-Ion Batteries.

As a typical two-dimensional layered metal sulfide, MoS2 has a high theoretical capacity and large layer spacing, which is beneficial for ion transport. Herein, a facile polymerization method is employed to synthesize polypyrrole (PPy) nanotubes, followed by a hydrothermal method to obtain flower-rod-shaped MoS2/PPy (FR-MoS2/PPy) composites. The FR-MoS2/PPy achieves outstanding electrochemical performance as a sodium-ion battery anode. After 60 cycles under 100 mA g−1, the FR-MoS2/PPy can maintain a capacity of 431.9 mAh g−1. As for rate performance, when the current densities range from 0.1 to 2 A g−1, the capacities only reduce from 489.7 to 363.2 mAh g−1. The excellent performance comes from a high specific surface area provided by the unique structure and the synergistic effect between the components. Additionally, the introduction of conductive PPy improves the conductivity of the material and the internal hollow structure relieves the volume expansion. In addition, kinetic calculations show that the composite material has a high sodium-ion transmission rate, and the external pseudocapacitance behavior can also significantly improve its electrochemical performance. This method provides a new idea for the development of advanced high-capacity anode materials for sodium-ion batteries.

PH-responsive mesoporous Fe2O3–Au nanomedicine delivery system with magnetic targeting for cancer therapy

Chemotherapy is the prime tool for the clinical treatment of cancer. The efficiency of treatment has been greatly improved with the assistance of nanomedicine delivery systems. However, it still meets the challenge of inefficient drug delivery and damage to normal tissues caused by uncontrolled drug release. Considering the various processes of nanomedicine acting on cancer cells, a pH-responsive mesoporous Fe2O3–Au nanomedicine delivery system with magnetic targeting was designed to achieve controlled drug release and improve the safety and efficiency. Fe2O3 particles were constructed with external mesopores and internal hollow structures, while Au nanoparticles were connected on the surface of Fe2O3 particles through pH-responsive valence bonds to encapsulate the drug. The Fe2O3–Au nanomedicine delivery system was equipped with magnetic targeting function, which could be induced by an external magnetic field to increase the drug concentration to kill cancer cells as well as reduce damage to normal cells. Meanwhile, based on the pH-responsive feature, the drug embedded could only be released in the weakly acidic condition of the cancer environment, while the nanomedicine delivery system remained closed in normal tissues. The Fe2O3–Au nanomedicine delivery system possessed the functions of pH responsiveness and magnetic targeting, enhancing safety and efficiency and providing a promising method for cancer therapy.

Concurrent thermal conductivity measurement and internal structure observation of individual one-dimensional materials using scanning transmission electron microscopy

The thermal conductivity of individual nanomaterials can vary from sample to sample due to the difference in geometries and internal structures, and thus, concurrent structure observation and thermal conductivity measurement at the nanoscale are highly desired but challenging. Here, we have developed an experimental method that allows concurrently the in situ thermal conductivity measurement and the real-time internal structure observation of a single one-dimensional (1D) material using scanning transmission electron microscopy (STEM) in a scanning electron microscope. In this method, the two ends of the 1D nanomaterial are bonded on a tungsten probe and a suspended platinum nanofilm, respectively. The platinum nanofilm serves simultaneously as a heater and a resistance thermometer, ensuring highly sensitive thermal measurements. The platinum nanofilm is fabricated on the edge of the silicon wafer so that the electron beam can transmit through the 1D material and be detected by the STEM detector, which caters for real-time observation of the inner nanostructure. Using this method, we in situ measured the thermal conductivities of two cup-stacked carbon nanotubes and concurrently observed the internal hollow structures. We found that the sample with more structural disorders had a lower thermal conductivity. Our measurement method can pave the way to the sample-by-sample elucidation of the structure–property relationship for 1D materials.

Enzymeless copper microspheres@carbon sensor design for sensitive and selective acetylcholine screening in human serum

Follow up of neuronal disorders, such as Alzheimer’s and Parkinson’s diseases using simple, sensitive, and selective assays is urgently needed in clinical and research investigation. Here, we designed a sensitive and selective enzymeless electrochemical acetylcholine sensor that can be used in human fluid samples. The designed electrode consisted of a micro spherical construction of Cu-metal decorated by a thin layer of carbon (CuMS@C). A simple and one-pot synthesis approach was used for Cu-metal controller formation with a spherical like structures. The spherical like structure was formed with rough outer surface texture, circular build up, homogeneous formation, micrometric spheres size (0.5 −1 µm), and internal hollow structure. The formation of a thin layer of carbon materials on the surface of CuMS sustained the catalytic activity of Cu atoms and enriched negatively charge of the surface. CuMS@C acted as a highly active mediator surface that consisted of Cu metal as a highly active catalyst and carbons as protecting, charge transport, and attractive surface. Therefore, the CuMS@C surface morphology and composition played a key role in various aspects such as facilitated ACh diffusion/loading, increased the interface surface area, and enhanced the catalytic activity. The CuMS@C acted as an electroactive catalyst for ACh electrooxidation and current production, due to the losing of two electrons. The fabricated CuMS@C could be a highly sensitive and selective enzymeless sensor for detecting ACh with a detection limit of 0.1 µM and a wide linear range of 0.01 – 0.8 mM. The designed ACh sensor assay based on CuMS@C exhibited fast sensing property as well as sensitivity, selectivity, stability, and reusability for detecting ACh in human serum samples. This work presents the design of a highly active electrode surface for direct detection of ACh and further clinical investigation of ACh levels.

Flammulina velutipes-like Co@NCNTs enhancing the electromagnetic wave absorption performance

Magnetic nitrogen-doped carbon nanotubes have been recognized as promising microstructures for electromagnetic wave absorption, benefiting from the internal hollow structure, excellent electrical conductivity and easy functionalization. Herein, a new composite composed of the thin-wall carbon nanotubes coated with the cobalt nanoparticles (hereafter labelled as: Co@NCNTs) on the tip was designed and synthesized through high temperature pyrolysis process. Revealed by scanning electron microscopy and X-ray photoelectron spectroscopy, the geometric and electronic structures of product were susceptible to the carbonization temperature. With the multiple dielectric polarization relaxations, higher magnetism and good impedance matching, the flammulina velutipes-like Co@NCNTs-700 exhibited the strongest dielectric loss, magnetic loss and electromagnetic wave absorption performance. The minimum reflection loss value and effective absorption bandwidth was determined to be −21.0 dB at 4.96 GHz and 5.28 GHz, respectively, superior to the previous reports. Furthermore, the thickness is at 2 mm and the filler mass loading is only 10%. Therefore, our present Co@NCNTs materials will be an ultralight material as potential high-efficiency EMW absorber.

Size-Dependent Synthesis of Hollow Co3O4 Nanocubes Derived from Co-Fe PBA as Battery-Type Electrode Materials for Hybrid Supercapacitors

Hollow nanostructures with enlarged surface areas are highly attractive electrode materials for supercapacitors. In this work, the size-dependent synthesis of hollow Co3O4 nanocubes via a facile ionic exchange reaction between Co-Fe Prussian blue analogues (PBAs) and alkali solution is reported. By adjusting the concentration of sodium citrate to control the reaction kinetics during nucleation and growth, four different sizes of Co-Fe PBAs were synthesized. It was also found that a Co-Fe PBA of about 140 nm can be easily converted into a well-defined internal hollow structure, while Co-Fe PBAs with smaller or larger sizes are challenged in generating a hollow structure. Benefitting from the inner voids and thin shell architecture, the derived hollow Co3O4 nanocubes exhibit a high specific capacity of 296.6C cm−2 at 2 mA cm−2, and a rate capability of 64.5% when the current density is increased to 60 mA cm−2. Furthermore, a hybrid supercapacitor (HSC) was fabricated with hollow Co3O4 nanocubes as the cathode and activated carbon as the anode, respectively. The HSC provided a maximum energy density of 14.1 Wh kg−1 at 464.7 W kg−1. Moreover, it retained the excellent cycling stability of 85.7% of the original capacity over 5000 continuous charging and discharging processes.

Silicon-Nanotube-Mediated Intracellular Delivery Enables Ex Vivo Gene Editing.

Engineered nano-bio cellular interfaces driven by vertical nanostructured materials are set to spur transformative progress in modulating cellular processes and interrogations. In particular, the intracellular delivery-a core concept in fundamental and translational biomedical research-holds great promise for developing novel cell therapies based on gene modification. This study demonstrates the development of a mechanotransfection platform comprising vertically aligned silicon nanotube (VA-SiNT) arrays for ex vivo gene editing. The internal hollow structure of SiNTs allows effective loading of various biomolecule cargoes; and SiNTs mediate delivery of those cargoes into GPE86 mouse embryonic fibroblasts without compromising their viability. Focused ion beam scanning electron microscopy (FIB-SEM) and confocal microscopy results demonstrate localized membrane invaginations and accumulation of caveolin-1 at the cell-NT interface, suggesting the presence of endocytic pits. Small-molecule inhibition of endocytosis suggests that active endocytic process plays a role in the intracellular delivery of cargo from SiNTs. SiNT-mediated siRNA intracellular delivery shows the capacity to reduce expression levels of F-actin binding protein (Triobp) and alter the cellular morphology of GPE86. Finally, the successful delivery of Cas9 ribonucleoprotein (RNP) to specifically target mouse Hprt gene is achieved. This NT-enhanced molecular delivery platform has strong potential to support gene editing technologies.

Sulfur@nitrogen-doped carbon yolk@shell nanospheres synthesized via in situ oxidation for Lithium–Sulfur batteries

How to construct the advanced sulfur cathode material with both high conductivity and well-defined structure is an important direction for Li–S batteries. In present study, we report a facile in situ method to prepare [email protected] carbon ([email protected]–C) [email protected] nanospheres (NSs) as cathodes for Lithium–Sulfur (Li–S) batteries. The In-situ synthesis strategy eliminates the problem of diffusion of LiPSs caused by sulfur accumulated on the outer surface of N–C. Moreover, the [email protected] structure reduces volume expansion upon lithiation through internal hollow structure and provides physical confinement and chemical adsorption of LiPSs by enclosed N–C outer shell. In addition, the electronic conductivity and reaction kinetic rate increased due to the doped nitrogen. As expected, the [email protected]–C NSs cathodes exhibited superior electrochemical performance for Li–S batteries (616 mAh g−1 at 1.0 C after 500 cycles).

Fabrication and characterization of PMMA/TiH2 energetic microcapsules with a hollow structure

ABSTRACT Energetic hollow microcapsules (EHMs) were designed as dual-functional sensitizers for emulsion explosive with pentane/TiH2 and poly(methyl methacrylate) (PMMA) as core and shell, respectively. SEM and particle size analyses showed that the PMMA/TiH2 energetic microcapsules had spherical morphology, narrow size distribution and internal hollow structure. The results of detonation performance and thermal safety experiments showed that the EHMs could be added in emulsion explosive as composite energetic sensitizers, which could provide “hot spots” and improve the detonation performance of emulsion explosive without affecting its safety. This method introduces an innovative way for the development of insensitive high-energy emulsion explosive, which would be applied to engineering blasting for hard rock mining and some military fields.

Glutathione Induced Transformation of Partially Hollow Gold-Silver Nanocages for Cancer Diagnosis and Photothermal Therapy.

Gold-silver nanocages (GSNCs) are widely used in cancer imaging and therapy due to excellent biocompatibility, internal hollow structures, and tunable optical properties. However, their possible responses toward the tumor microenvironment are still not well understood. In this study, it is demonstrated that a kind of relatively small sized (35 nm) and partially hollow GSNCs (absorbance centered at 532 nm) can enhance the intrinsic photoacoustic imaging performances for blood vessels around tumor sites. More importantly, the high concentration of glutathione around the tumor cells' microenvironment may induce the aggregation, disintegration, and agglomeration of these GSNCs sequentially, allowing significant shifts in the absorbance spectrum of GSNCs to the near-infrared (NIR) region. This enhanced absorbance in the NIR region entails the significant photothermal therapy (PTT) effect. In vivo experiments, including photoacoustic microscopy (PAM) for cancer diagnosis and PTT in tumor model mice, also show coincident consequences. Taken together, the slightly hollow GSNCs may assist PAM-based tumor diagnosis and induce a tumor targeted PTT effect. This work paves a new avenue for the development of an alternative tumor diagnostic and therapeutic strategy.

Double layered dielectric elastomer by vapor encapsulation casting for highly deformable and strongly adhesive triboelectric materials

Triboelectric generators (TEG), based on contact electrification and electro-static induction, has received a significant attention because of their numerous applications. To improve the electrified surface charge density in TEG, increasing the surface area of dielectric materials or forming internal hollow structures are typically employed to increase capacitance. However, the fabrication processes of such structures are complex and time-consuming. Here, we provide a facile and cost-effective synthesis method for the porous PDMS based TEG via a novel vapor encapsulation casting (VEC). The double dielectric layer composed of the porous and dense PDMS layers are formed in-site through VEC. The thickness and the thickness ratio of the double dielectric layer can be precisely controlled by adjusting the uncured PDMS thickness and vapor penetration depth. The double dielectric layer TEG (DTEG) exhibits the improved harvesting performance because the porous dielectric layer increases the capacitance and compressibility, while the dense layer passivates the fully open pores which reduce the charging surface area as completely opening through the dielectric layer without contacting the bottom electrode. We obtain the maximum output voltage of 345 V and short circuit current of 3 μA/cm2 from DTEG having 0.95 porous thickness ratio, resulting 330% enhancement in the power output as compared to the dense PDMS based TEG. We further investigate the performance of DTEG under various operating conditions. We also demonstrate the operation of Bluetooth distance/temperature sensors using capacitors charged by DTEG.