Functional toner for office laser printer and its application for printing of paper-based superwettable patterns and devices

Abstract Laserjet printing is a kind of facile and digital do-it-yourself strategies, which is of importance to fabricate inexpensive paper-based microfluidic devices. However, the printed hydrophobic barrier is not hydrophobic enough due to the weak hydrophobicity and requires subsequent heating, which can lead to the pyrolysis of cellulose in the paper and influence the detection results. Here, for the first time, we report a kind of functional toner including toner and polydopamine (PDA) nanocapsules which contains oleic acid modified ferric tetroxide (OA-Fe3O4) and octadecylamine (ODA), which is suitable for printing with desired shapes and sizes to lead to formation of superhydrophobic barriers. Moreover, patterns printed with functional toner have good stability, including resistance to moisture, ultraviolet (UV) and bending. Finally, a proof-of-concept of metal and nitrite ions testing is demonstrated using colorimetric analysis, and the results show that the printed devices successfully perform instant detection of ions. The developed functional toner offers easy fabrication, cost-effectiveness and mass production of paper-based devices. In general, this strategy provides a new idea and technical support for the rapid prototyping of microfluidic paper-based analytical devices (μPADs) using laserjet printing

Convexity, polyconvexity and finite element implementation of a four-fiber anisotropic hyperelastic strain energy density—Application to the modeling of femoral, popliteal and tibial arteries

International audienceComputational analysis of the nonlinear mechanical properties of anisotropic hyperelastic materials aims at a better understanding of its physiology and pathophysiology under different loading conditions. This has an important role in biomechanics, surgical, clinical diagnostic and design of medical devices. This study investigates the modeling of arterial tissues made of a four-fiber family by using an anisotropic hyperelastic model. This model is based on the theory of polynomial invariant and was implemented in the university finite element code FER. The convex property of the strain energy function is investigated as well as the positive definite nature of the tangent stiffness matrix used within the framework of a finite element analysis. This allows us to guarantee the invertibility of the linearized problem and the uniqueness of the solution computed at each step of the Newton–Raphson scheme used to solve nonlinear problems

Electrospun Nanofiber Materials for Photothermal Interfacial Evaporation

Photothermal interfacial evaporation with low cost and environmental friendliness has attracted much attention. However, there are still many problems with this technology, such as heat loss and salt accumulation. Due to their different structures and adjustable chemical composition, electrospun nanofiber materials generally exhibit some unique properties that provide new approaches to address the aforementioned issues. In this review, the rational design principles for improving the total efficiency of solar evaporation are described for thermal/water management systems and salt-resistance strategies. And we review the state-of-the-art advancements in photothermal evaporation based on nanofiber materials and discuss their derivative applications in desalination, water purification, and power generation. Finally, we highlight key challenges and opportunities in both fundamental research and practical applications to inform further developments in the field of interfacial evaporation

Rhein-based necrosis-avid MRI contrast agents for early evaluation of tumor response to microwave ablation therapy

PURPOSE: Early evaluation of tumor response to thermal ablation therapy can help identify untreated tumor cells and then perform repeated treatment as soon as possible. The purpose of this work was to explore the potential of rhein-based necrosis-avid contrast agents (NACAs) for early evaluation of tumor response to microwave ablation (MWA). METHODS: 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was performed to test the cytotoxicity of rhein-based NACAs against HepG2 cells. Rat models of liver MWA were used for investigating the effectiveness of rhein-based NACAs in imaging the MWA lesion, the optimal time period for post-MWA MRI examination, and the metabolic behaviors of 68 Ga-labeled rhein-based NACAs. Rat models of orthotopic liver W256 tumor MWA were used for investigating the time window of rhein-based NACAs for imaging the MWA lesion, the effectiveness of these NACAs in distinguishing the residual tumor and the MWA lesion, and their feasibility in early evaluating the tumor response to MWA. RESULTS: Gadolinium 2,2',2''-(10-(2-((4-(4,5-Dihydroxy-9,10-dioxo-9,10-dihydroanthracene-2-carboxamido)butyl)amino)-2-oxoethyl)-1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid (GdL2 ) showed low cytotoxicity and high quality in imaging the MWA region. The optimal time period for post-MWA MRI examination using GdL2 was 2 to 24 h after the treatment. During 2.5 to 3.5 h postinjection, GdL2 can better visualize the MWA lesion in comparison with gadolinium 2-[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid (Gd-DOTA), and the residual tumor would not be enhanced. The tumor response to MWA as evaluated by using GdL2 -enhanced MRI was consistent with histological examination. CONCLUSION: GdL2 appears to be a promising NACA for the tumor response assessment after thermal ablation therapies.status: publishe

Synthesis and Evaluation of Diindole-Based MRI Contrast Agent for In Vivo Visualization of Necrosis

PURPOSE: Noninvasive imaging of cell necrosis can provide an early evaluation of tumor response to treatments. Here, we aimed to design and synthesize a novel diindole-based magnetic resonance imaging (MRI) contrast agent (Gd-bis-DOTA-diindolylmethane, Gd-DIM) for assessment of tumor response to therapy at an early stage. PROCEDURES: The oil-water partition coefficient (Log P) and relaxivity of Gd-DIM were determined in vitro. Then, its necrosis avidity was examined in necrotic cells in vitro and in rat models with microwave ablation-induced muscle necrosis (MAMN) and ischemia reperfusion-induced liver necrosis (IRLN) by MRI. Visualization of tumor necrosis induced by combretastatin A-4 disodium phosphate (CA4P) was evaluated in rats bearing W256 orthotopic liver tumor by MRI. Finally, DNA binding assay was performed to explore the possible necrosis-avidity mechanism of Gd-DIM. RESULTS: The Log P value and T1 relaxivity of Gd-DIM is - 2.15 ± 0.01 and 6.61 mM-1 s-1, respectively. Gd-DIM showed predominant necrosis avidity in vitro and in vivo. Clear visualization of the tumor necrosis induced by CA4P was achieved at 60 min after administration of Gd-DIM. DNA binding study indicated that the necrosis-avidity mechanism of Gd-DIM may be due to its binding to exposed DNA in necrotic cells. CONCLUSION: Gd-DIM may serve as a promising necrosis-avid MRI contrast agent for early assessment of tumor response to therapy.status: publishe