Hollow Microrods Research Articles

Immunogenic Material Vaccine for Cancer Immunotherapy by Structure-Dependent Immune Cell Trafficking and Modulation.

Inherently immunogenic materials offer enormous prospects in enhancing vaccine efficacy. However, the understanding and improving material adjuvanticity remain elusive. Herein how the structural presentation of immunopotentiators in a material governs the dynamic dialogue between innate and adaptive immunity for enhanced cancer vaccination is reported. The immunopotentiator manganese into six differing structures that resemble the architectures of two types of pathogens (spherical viruses or rod-like bacteria) is precisely manipulated. The results reveal that innate immune cells accurately sense and respond to the architectures, of which two outperformed material candidates (151nm hollow spheres and hollow microrods with an aspect ratio of 4.5) show higher competence in creating local proinflammatory environment with promoted innate immune cell influx and stimulation on dendritic cells (DCs). In combination with viral peptides, model proteins, or cell lysate antigens, the outperformed microrod material remarkably primes antigen-specific CD8 cytolytic T cells. In prophylactic and therapeutic regimens, the microrod adjuvanted vaccines display optimal aptitude in tumor suppression in four aggressive murine tumor models, by promoting the infiltration of heterogeneous cytolytic effector cells while decreasing suppressive immunoregulatory populations in tumors. This study demonstrates that a rationally selected architecture of immunogenic materials potentially advances the clinical reality of cancer vaccination.

Synthesis of ZnO nanosheets @In2O3 hollow micro-rods heterostructures for enhanced ethanol gas sensing performance

In this paper, the ZnO nanosheets @In2O3 hollow microrods heterostructures were successfully prepared by co-precipitation and annealing methods. It was observed by SEM and TEM that the surface of the In2O3 hollow microrods was uniformly coated with porous ZnO nanosheets, which increased the specific surface area of ZnO@In2O3 composites. The In2O3 hollow microrods functions as electron transport channels and facilitate the transfer of electrons between ZnO nanosheets, consequently elevating the base resistance of sensors. The maximum sensor response of ZnO@In2O3-2 (the molar ratio of ZnO and In2O3 is 5:2) was 269.1 for 100 ppm ethanol at the optimal working temperature of 200 ºC, which is about 30.9 times higher than that of pure ZnO nanosheets (8.7) and 19.1 times higher than that of pure In2O3 (14.1). Additionally, the ZnO@In2O3-2 composites exhibit rapid response-recovery times, excellent selectivity and favorable stability. The improved gas sensing performance of ZnO@In2O3-2 heterostructures were ascribed to its heterogeneous structure building, abundant oxygen vacancies, large specific surface area and internal electric field through characterized by XPS, EPR, and BET.

Facile Construction of Porous ZnMn2O4 Hollow Micro-Rods as Advanced Anode Material for Lithium Ion Batteries.

Spinel ZnMn2O4 is considered a promising anode material for high-capacity Li-ion batteries due to their higher theoretical capacity than commercial graphite anode. However, the insufficient cycling and rate properties seriously limit its practical application. In this work, porous ZnMn2O4 hollow micro-rods (ZMO HMRs) are synthesized by a facile co-precipitation method coupled with annealing treatment. On the basis of electrochemical analyses, the as-obtained samples are first characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and scanning electron microscopy techniques. The influences of different polyethylene glycol 400 (PEG 400) additions on the formation of the hollow rod structure are also discussed. The abundant multi-level pore structure and hollow feature of ZMO HMRs effectively alleviate the volume expansion issue, rendering abundant electroactive sites and thereby guaranteeing convenient Li+ diffusion. Thanks to these striking merits, the ZMO HMRs anode exhibits excellent electrochemical lithium storage performance with a reversible specific capacity of 761 mAh g-1 at a current density of 0.1 A g-1, and a long-cycle specific capacity of 529 mAh g-1 after 1000 cycles at 2.0 A g-1 and keep a remarkable rate capability. In addition, the assembled ZMO HMRs-based full cells deliver an excellent rate capacity, and when the current density returns to 0.05 A g-1, the specific capacity can still reach 105 mAh g-1 and remains at 101 mAh g-1 after 70 cycles, maintaining a material-level energy density of approximately 273 Wh kg-1. More significantly, such striking electrochemical performance highlights that porous ZMO HMRs could be a promising anode candidate material for LIBs.

Porous ZnMn2O4 hollow microrods: Facile construction and excellent electrochemical performances for lithium ion batteries

Porous ZnMn2O4 hollow microrods have been constructed through a facile co-precipitation method followed by an annealing process. The plausible formation mechanism for the unique architecture of ZnMn2O4 microrods was proposed and discussed in detail. It is found that the calcination temperature plays a key role in determining the microstructures of ZnMn2O4. On the whole, 700 °C is the optimal temperature, which not only makes the as-constructed ZnMn2O4 microrods (denoted as ZMO-700) the porous and hollow architecture, but also owns a good crystallinity, high porosity and large specific surface area. When used as anode materials for lithium ion batteries, the ZMO-700 exhibits outstanding electrochemical performances. It both possesses a high reversible capacity of 902 mAh g−1 after 320 cycles at 0.5 C, and presents an excellent rate capability in the current rate region of 0.1–5 C, especially deliveries a high capacity of 223 mAh g−1 at 5 C. The significant enhancement in the electrochemical performances should be attributed to the synergistic effect of the porous hollow architecture and the micro-nano hierarchical structure for the as-constructed ZnMn2O4 anode.

Minimally invasive co-injection of modular micro-muscular and micro-vascular tissues improves in situ skeletal muscle regeneration

Various conventional treatment strategies for volumetric muscle loss (VML) are often hampered by the extreme donor site morbidity, the limited availability of quality muscle flaps, and complicated, as well as invasive surgical procedures. The conventional biomaterial-based scaffolding systems carrying myoblasts have been extensively investigated towards improving the regeneration of the injured muscle tissues, as well as their injectable forms. However, the applicability of such designed systems has been restricted due to the lack of available vascular networks. Considering these facts, here we present the development of a unique set of two minimally invasively injectable modular microtissues, consisting of mouse myoblast (C2C12)-laden poly(lactic-co-glycolic acid) porous microspheres (PLGA PMs), or the micro-muscles, and human umbilical vein endothelial cell (HUVEC)-laden poly(ethylene glycol) hollow microrods (PEG HMs), or the microvessels. Besides systematic in vitro investigations, the myogenic performance of these modular composite microtissues, when co-injected, was explored in vivo using a mouse VML model, which confirmed improved in situ muscle regeneration and remolding. Together, we believe that the construction of these injectable modular microtissues and their combination for minimally invasive therapy provides a promising method for in situ tissue healing.

Ionic liquid assisted synthesis of h-MoO3 hollow microrods and their application for electrochemical sensing of Imidacloprid pesticide in vegetables

Herein, we demonstrate the ionic liquid (1-butyl-3-methylimidazolium bromide [BMIM]+ [Br]−) assisted solvo-hydrothermal synthesis of novel hexagonal MoO3 hollow microrods (h-MoO3 HRs). The h-MoO3 HRs were preferentially obtained through the formation of electric double layer and strong electrostatic interactions of ionic liquids with colloidal particles, including the electrons and ions. As-synthesized h-MoO3 HRs were further anchored on glassy carbon electrode (h-MoO3 HRs/GCE) and directly employed as a working electrode towards the electrochemical sensing of Imidacloprid (IMD) pesticide. The electrochemical response of IMD at h-MoO3 HRs/GCE was verified by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The h-MoO3 HRs/GCE electrode exhibited two distinct quasireversible redox couple towards IMD. From the CV and DPV, the sensitivity was calculated to be 2.02 × 10−1 A L mol−1 cm−2 and 1.39 × 10−1 A L mol−1 cm−2, respectively. Under optimal conditions, h-MoO3 HRs/GCE sense IMD with wide linear range of CV from 38.7 to 114 μM and from DPV 38.7 to 132 μM. The estimated detection limits from CV and DPV was calculated as 8.3 and 5.9 μM, respectively. In view of practical application, the proposed electrochemical sensor h-MoO3 HRs/GCE is successfully applied for the detection of IMD at low levels in vegetable samples.

Synergistic Modulation of Active Sites and Charge Transport: N/S Co-doped C Encapsulated NiCo2O4/NiO Hollow Microrods for Boosting Oxygen Evolution Catalysis.

Developing high-efficiency and cost-effective electrocatalysts for the oxygen evolution reaction (OER) is crucial for various energy conversion systems. Herein, N/S co-doped C encapsulated hollow NiCo2O4/NiO hexagonal rods (HNHR@N/S-C) as the electrocatalysts for OER have been successfully prepared with rational control of structure and composition. Experimental and theoretical results have highlighted that the NiCo2O4/NiO heterojunction in the obtained electrocatalyst can provide abundant active Ni and Co sites for the OER, leading to the highly enhanced OER performance. Moreover, attributed to the hierarchical hollow structure, which can provide a large surface area, and the improved electric conductivity with a coating of the N/S co-doped carbon layer, which can facilitate charge transport during the catalytic processes, a remarkable OER activity over HNHR@N/S-C with a low overpotential (η) of 285 mV (at j = 10 mA cm-2) and a Tafel slope of 53.0 mV decade-1 has been achieved, which is comparable to that of the noble metal catalyst IrO2. Because of the protection of the N/S doped C layer coating, HNHR@N/S-C can also maintain the current density of 10 mA cm-2 for at least 12 h in alkaline media without obvious losses of activity.

Facile metal-organic frameworks-templated fabrication of hollow indium oxide microstructures for chlorine detection at low temperature

Metal oxides with the hollow microstructure by the facile synthetic strategy are hopeful in applications for photocatalysis, supercapacitor, and gas sensor owing to their large surface areas, porosity ratio and rich active sites. In this work, indium oxide porous hollow rods (In2O3 PHRs) are successfully prepared using metal-organic frameworks (MOFs) as the template. The morphology of In2O3 PHRs is hexagonal hollow micro-rods with a porous structure. The investigation on the gas-sensing performance reveals that the In2O3 PHRs sensor displays outstanding sensitivity and selectivity toward 10 ppm chlorine gas (Cl2) at low operational temperature (160 °C). Furthermore, the In2O3 PHRs sensor displays a low detection limit (3.2 ppb) and short response and recovery time (38/13 s). The unique morphology and abundant oxygen vacancies are conduced to the excellent gas-sensing activities, which is benefited from the utilization and decomposition of In-MOFs precursor. In addition, the gas sensing mechanism of reducing gases and oxidizing gases is deduced in detail for the In2O3 PHRs sensor.

Preparation and NH3 Gas-Sensing Properties of Double-Shelled Hollow ZnTiO3 Microrods.

A novel double-shelled hollow (DSH) structure of ZnTiO3 microrods was prepared by self-templating route with the assistance of poly(diallyldimethylammonium chloride) (PDDA) in an ethylene glycol (EG) solution, which was followed by calcining. Moreover, the NH3 gas-sensing properties of the DSH ZnTiO3 microrods were studied at room temperature. The morphology and composition of DSH ZnTiO3 microrods films were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The formation process of double-shelled hollow microrods was discussed in detail. The comparative gas-sensing results revealed that the DSH ZnTiO3 microrods had a higher response to NH3 gas at room temperature than those of the TiO2 solid microrods and DSH ZnTiO3 microrods did in the dark. More importantly, the DSH ZnTiO3 microrods exhibited a strong response to low concentrations of NH3 gas at room temperature.

Graphene oxide-wrapped dipotassium terephthalate hollow microrods for enhanced potassium storage.

Unique graphene oxide-wrapped organic dipotassium terephthalate hollow microrods were synthesised using an abundant and renewable organic resource. They exhibit enhanced potassium storage compared to bulk K2TP, which can be ascribed to the fast K+ ion transfer kinetics, high electronic conductivity and short diffusion distance.

Preparation of Straight and Orderly Polypyrrole Microrods through Soft Template Methods

The straight and orderly microrods of polypyrrole(PPy) was synthesized in a microemulsion system consisted of cetyltrimethylammonium bromide(CTAB), n-pentanol, water and pyrrole by chemical oxidative polymerization, in which CTAB was used as soft templates and APS was used as the oxidant. Fourier-transform infrared spectroscopy (FTIR) was used to characterize the structure of the PPy microrods. Transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) was used to characterize the morphology of the samples. We discussed the impact of temperature, the adding way of the oxidant, the amount of cosurfactant n-pentanol to the morphology of PPy microrods. The results showed that straight and orderly PPy microrods with a diameter about 300nm and a length up to 20μm were synthesized when the temperature was kept at room temperature (25°C), the dropping time of APS was more than 1.5h, the ratio of CTAB to n-pentanol was 0.6:1, and the polymerization time was about 24h. We studied the growth process of PPy microrods by HTEM analysis. HTEM images revealed that the growth process of PPy changed from hollow microrods, semi-hollow microrods, and finally solid microrods.

Escherichia coli Bacteria-Templated Synthesis of Nanoporous Cadmium Sulfide Hollow Microrods for Efficient Photocatalytic Hydrogen Production

A simple sonochemical method has been utilized to synthesize nanoporous hollow structures of semiconducting cadmium sulfide (CdS) using Escherichia coli bacteria as template. To enable adsorption and reaction throughout the E. coli cell envelope, the cell permeability is enhanced by suitable ethanol treatment while preserving the morphology. With cadmium acetate and thioacetamide as reactants, CdS nanostructures in the form of monodisperse quantum dots, nearly monodisperse nanocrystals, and nanoporous hollow microrods are controllably formed on ethanol-treated E. coli with increasing reaction time. Additionally, nanorod antennas have been fabricated by utilizing the pili formed during the growth phase of the bacteria. The CdS crystal structure can be tuned from being pure cubic to a mixture of cubic and hexagonal or pure hexagonal by simply adjusting the sulfur/cadmium molar ratio of the reactants. Photoanodes fabricated using the hexagonal structured CdS nanoporous hollow microrods exhibit excellent perf...