Publications by authors named "Jiahua Ni"

M2 macrophages promote adipose tissue thermogenesis which dissipates energy in the form of heat to combat obesity. However, the regulation of M2 macrophages by thermogenic adipocytes is unclear. Here, it is identified magnesium (Mg) as a thermogenic adipocyte-secreted factor to promote M2 macrophage polarization.

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Improving the comprehensive performance of low alloyed Mg is a significant challenge for biomedical applications. This paper developed a high-performance Mg-Zn alloy with uniform ultrafine grains and nano-precipitates through a straightforward, high-temperature reciprocating equal channel angle extrusion (ECAP) process and researched the microstructure, mechanical property, degradation behaviour, and biocompatibility of the developed alloy. Results showed that the lean Mg-2Zn alloy successfully refined grain to about 1 μm and produced plenty of nano-particles with uniform distribution, providing high comprehensive mechanical properties (YS: 235 MPa, UTS: 267 MPa, EL: 15.

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We develop soft and stretchable fatigue-resistant hydrogel optical fibers that enable optogenetic modulation of peripheral nerves in naturally behaving animals during persistent locomotion. The formation of polymeric nanocrystalline domains within the hydrogels yields fibers with low optical losses of 1.07 dB cm, Young's modulus of 1.

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Osteosarcoma, the most common primary malignant bone tumor, is characterized by malignant cells producing osteoid or immature bone tissue. Most osteosarcoma patients require reconstructive surgery to restore the functional and structural integrity of the injured bone. Metal orthopedic implants are commonly used to restore the limb integrity in postoperative patients.

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Article Synopsis
  • Current semi-crystalline structures of cryogels limit their use in soft devices because of uncontrolled freezing, which adversely affects performance.
  • A new strategy is introduced that involves fully amorphizing the polymer to achieve multifunctionality by using antifreeze salts to control the freezing process, leading to better polymer chain aggregation.
  • The result is a new type of cryogel with exceptional properties like tissue-like softness, high stretchability, transparency, self-adhesion, rapid self-healing, and improved ionic conductivity, paving the way for advanced skin-like electronic applications.
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Background: Research on the growth mechanism of titanium dioxide (TiO) nanotube arrays fabricated by anodic oxidation is essential to achieve artificial control of the microstructure and to expand their applications. In our previous work, we reported the preparation of highly ordered large-diameter double-wall TiO nanotube arrays prepared by high voltage anodization.

Methods: In this paper, we observed and analyzed the initial growth process of large-diameter double-wall TiO nanotube arrays anodized at 120 V in ethylene glycol electrolyte containing aluminum fluoride (NHF) and water (HO), such as the evolution of surface and cross-sectional morphologies, the influence of current density on growth rate, the transition process from nanoholes to nanotubes, and the evolution of dimples on the remaining substrate.

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Article Synopsis
  • Sporopollenin is a tough and chemically stable biopolymer that forms the outer layer of plant spores and pollen, which has unique structural characteristics compared to other biopolymers.* -
  • Researchers successfully created synthetic versions of sporopollenin that match parts of the pine sporopollenin structural model, demonstrating strong mechanical and thermal properties.* -
  • This study paves the way for designing new durable materials inspired by natural sporopollenin and offers insights into how sporopollenin is produced in plants.*
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Moderately regulating vascularization and immune microenvironment of wound site is necessary to achieve scarless wound healing of the skin. Herein, we have prepared an angiogenesis-promoting and scar-preventing band-aid with a core-shell structure, that consists of MXene-loaded nanofibers (MNFs) as the core and dopamine-hyaluronic acid hydrogel (H) as the shell (MNFs@V-H@DA) to encapsulate a growth factor (vascular endothelial growth factor, VEGF, abbreviated as V) and HS donor (diallyl trisulfide, DATS, abbreviated as DA). The continuous release of DA from this system produced HS, which would successfully induce macrophages to polarize into M2-lile phenotype, regulating the immune microenvironment and inhibiting an excessive inflammatory response at the wound sites.

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Imaging-guided photothermal therapy (PTT)/photodynamic therapy (PDT) for cancer treatment are beneficial for precise localization of the malignant lesions and combination of multiple cell killing mechanisms in eradicating stubborn thermal-resistant cancer cells. However, overcoming the adverse impact of tumor hypoxia on PDT efficacy remains a challenge. Here, carrier-free nano-theranostic agents are developed (AIBME@IR780-APM NPs) for magnetic resonance imaging (MRI)-guided synergistic PTT/thermodynamic therapy (TDT).

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Hydrogen has been used to suppress tumor growth with considerable efficacy. Inhalation of hydrogen gas and oral ingestion of hydrogen-rich saline are two common systemic routes of hydrogen administration. We have developed a topical delivery method of hydrogen at targeted sites through the degradation of magnesium-based biomaterials.

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Biodegradable magnesium (Mg) implants spontaneously releasing therapeutic agents against tumors are an intriguing therapeutic approach for both tissue repair and tumor treatment. Anastomotic staples are extensively used for wound closure after surgical resection in patients with colorectal tumors. However, the safety of Mg anastomosis implants for intestinal closure and the effect of tumor suppression remain elusive.

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Lean alloy (low alloyed) is beneficial for long-term sustainable development of metal materials. Creating a nanocrystalline microstructure is a desirable approach to improve biodegradability and mechanical properties of lean biomedical Mg alloy, but it is nearly impossible to realize. In the present study, the bulk nanocrystalline Mg alloy (average grain size: ~70 nm) was successfully obtained by hot rolling process of a lean Mg-2wt.

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Gallbladder cancer can be difficult to detect in its early stages and is prone to metastasize, causing bile duct obstruction, which is usually treated by stent implantation in clinic. However, the commonly used biliary stents are non-degradable, which not only prone to secondary blockage, but also need to be removed by secondary surgery. Biodegradable magnesium (Mg) is expected to one of the promising candidates for degradable biliary stents due to its excellent physicochemical property and biocompatibility.

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The common treatment of epithelial ovarian cancer is aggressive surgery followed by platinum-based cytotoxic chemotherapy. However, residual tumor cells are resistant to chemotherapeutic drugs during postoperative recurrence. The treatment of ovarian cancer requires breakthroughs and advances.

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Microchannels in hydrogels play an essential role in enabling a smart contact lens. However, microchannels have rarely been created in commercial hydrogel contact lenses due to their sensitivity to conventional microfabrication techniques. Here, we report the fabrication of microchannels in poly(2-hydroxyethyl methacrylate) (poly(HEMA)) hydrogels that are used in commercial contact lenses with a three-dimensional (3D) printed mold.

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Because of excellent corrosion resistance, biocompatibility, high toughness, high hardness and moderate mechanical strength, Ta metals have excellent prospects for biomedical applications, especially implants. Many substances that interact directly with cells to affect their behavior have nanoscale topologies whose processes affect cells are also on the order of nanometer size. In this work, the surface of the nanotube structure is observed and the inner and outer diameters of the nanotubes are measured by scanning electron microscope (SEM).

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Microstructural design was a long-term sustainable development method to improve the biodegradability and mechanical properties of low alloyed biomedical Mg alloys. In this study, the microstructural features (including grain size, deformation twin, deformed grains, sub-grains, and recrystallized grains) of the MZ2 ((Mg-2Zn (wt%)) alloy were controlled by different single-passed rolling reductions at high temperature. Besides the effect of grain size, we found that deformation twins and deformed grains influenced corrosion performance.

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Mg-based implants are used in biomedical applications predominantly because of their degradable property. In this paper, the effect of local misorientations (intragranular misorientation) on the corrosion behavior of high-purity Mg (HPM) was systematically investigated according to microstructure characterization and corrosion measurements. The results showed that local misorientation introduced into grains by deformation could result in corrosion around the grain boundary (GB), which ultimately reduces the corrosion resistance of HPM.

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There is an increasing need to develop conducting hydrogels for bioelectronic applications. In particular, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) hydrogels have become a research hotspot due to their excellent biocompatibility and stability. However, injectable PEDOT:PSS hydrogels have been rarely reported.

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Crevice-induced corrosion is not desirable to occur in metallic magnesium (Mg) during many industrial applications. However, orthopedic implants made of Mg alloys have been demonstrated to degrade faster between the joining surface of bone plates and screws after implantation, suggesting the crevice corrosion may occur in the physiological environment. In this paper, a resin device is designed to parallel high purity magnesium (HP-Mg) plates with closely spaced slits.

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A highly ordered TiO nanotube array has been prepared on a commercial pure titanium substrate in a hydrofluoric (HF) electrolyte using a DC power source through two-step anodic oxidation. The morphology, composition, wettability and surface energy of the nanotube array have been characterized by using a field-emission scanning electron microscope (FE-SEM), a transmission electron microscope (JEM-2010) with energy-dispersive X-ray spectrometer EDX (INCA OXFORD), X-ray diffraction method, an atomic force microscope (AFM), an optical contact angle measuring device and the Owens method with two liquids. The electrochemical behaviours of anodic oxidation films with different structures have been investigated in Sodium Lactate Ringer's Injection at 37±1°C by potentiodynamic polarization curve and electrochemical impedance spectroscopy.

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Cells secrete substances that are essential to the understanding of numerous immunological phenomena and are extensively used in clinical diagnoses. Countless techniques for screening of biomarker secretion in living cells have generated valuable information on cell function and physiology, but low volume and real-time analysis is a bottleneck for a range of approaches. Here, a simple, highly sensitive assay using a high-throughput micropillar and microwell array chip (MIMIC) platform is presented for monitoring of biomarkers secreted by cancer cells.

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Background And Study Aims:  Computed tomography (CT) and magnetic resonance image (MRI) data have been widely used to for navigation in various neurosurgical operations. However, delicate intracranial structures cannot be displayed using only one imaging method. Navigation with multimodality imaging was developed to better visualize these structures in glioma removal, but whether it is useful in endoscopic transsphenoidal surgery is unknown.

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Magnesium is a type of reactive metal, and is susceptible to galvanic corrosion. In the present study, the impact of coexistence of Ti on the corrosion behavior of high purity Mg (HP Mg) was investigated both in vitro and in vivo. Increased corrosion rate of HP Mg was demonstrated when Mg and Ti discs were not in contact.

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