scholarly journals A Review of Fast Bubble-Driven Micromotors Powered by Biocompatible Fuel: Low-Concentration Fuel, Bioactive Fluid and Enzyme

Micromachines ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 537 ◽  
Author(s):  
Qingjia Chi ◽  
Zhen Wang ◽  
Feifei Tian ◽  
Ji’an You ◽  
Shuang Xu
Keyword(s):  
Drug Delivery ◽  
Hydrogen Peroxide ◽  
Environmental Protection ◽  
Glucose Oxidase ◽  
Cell Separation ◽  
High Speed ◽  
Recoil Effect ◽  
Low Concentration ◽  
Practical Applications ◽  
Good Biocompatibility

Micromotors are extensively applied in various fields, including cell separation, drug delivery and environmental protection. Micromotors with high speed and good biocompatibility are highly desirable. Bubble-driven micromotors, propelled by the recoil effect of bubbles ejection, show good performance of motility. The toxicity of concentrated hydrogen peroxide hampers their practical applications in many fields, especially biomedical ones. In this paper, the latest progress was reviewed in terms of constructing fast, bubble-driven micromotors which use biocompatible fuels, including low-concentration fuels, bioactive fluids, and enzymes. The geometry of spherical and tubular micromotors could be optimized to acquire good motility using a low-concentration fuel. Moreover, magnesium- and aluminum-incorporated micromotors move rapidly in water if the passivation layer is cleared in the reaction process. Metal micromotors demonstrate perfect motility in native acid without any external chemical fuel. Several kinds of enzymes, including catalase, glucose oxidase, and ureases were investigated to serve as an alternative to conventional catalysts. They can propel micromotors in dilute peroxide or in the absence of peroxide.

Recent Patents on the Angular Contact Ball Bearing of High-Speed Motorized Spindle

2020 ◽  
Vol 13 ◽  
Author(s):  
Yudong Bao ◽  
Linkai Wu ◽  
Yanling Zhao ◽  
Chengyi Pan
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Rapid Development ◽  
Ceramic Materials ◽  
Development Trend ◽  
Numerical Control ◽  
Angular Contact Ball Bearing ◽  
Practical Applications ◽  
High Speed Cutting ◽  
Advantages And Disadvantages

Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

scholarly journals The Impact of Lipid Handling and Phase Distribution on the Acoustic Behavior of Microbubbles

Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 119
Author(s):  
Simone A.G. Langeveld ◽  
Inés Beekers ◽  
Gonzalo Collado-Lara ◽  
Antonius F. W. van der Steen ◽  
Nico de Jong ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Molecular Imaging ◽  
High Speed ◽  
Phase Distribution ◽  
Direct Method ◽  
Ultrasound Contrast Agents ◽  
Lipid Phase ◽  
Acoustic Behavior ◽  
Ultrasound Molecular Imaging ◽  
The Impact

Phospholipid-coated microbubbles are ultrasound contrast agents that can be employed for ultrasound molecular imaging and drug delivery. For safe and effective implementation, microbubbles must respond uniformly and predictably to ultrasound. Therefore, we investigated how lipid handling and phase distribution affected the variability in the acoustic behavior of microbubbles. Cholesterol was used to modify the lateral molecular packing of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC)-based microbubbles. To assess the effect of lipid handling, microbubbles were produced by a direct method, i.e., lipids directly dispersed in an aqueous medium or indirect method, i.e., lipids first dissolved in an organic solvent. The lipid phase and ligand distribution in the microbubble coating were investigated using confocal microscopy, and the acoustic response was recorded with the Brandaris 128 ultra-high-speed camera. In microbubbles with 12 mol% cholesterol, the lipids were miscible and all in the same phase, which resulted in more buckle formation, lower shell elasticity and higher shell viscosity. Indirect DSPC microbubbles had a more uniform response to ultrasound than direct DSPC and indirect DSPC-cholesterol microbubbles. The difference in lipid handling between direct and indirect DSPC microbubbles significantly affected the acoustic behavior. Indirect DSPC microbubbles are the most promising candidate for ultrasound molecular imaging and drug delivery applications.

scholarly journals Microparticles, Microspheres, and Microcapsules for Advanced Drug Delivery

2019 ◽  
Vol 87 (3) ◽  
pp. 20 ◽  
Author(s):  
Miléna Lengyel ◽  
Nikolett Kállai-Szabó ◽  
Vince Antal ◽  
András József Laki ◽  
István Antal
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Freeze Drying ◽  
Delivery Systems ◽  
The Novel ◽  
Practical Applications ◽  
Inhaled Insulin ◽  
Formulation Factors ◽  
Novel Drug ◽  
Significant Production

Microparticles, microspheres, and microcapsules are widely used constituents of multiparticulate drug delivery systems, offering both therapeutic and technological advantages. Microparticles are generally in the 1–1000 µm size range, serve as multiunit drug delivery systems with well-defined physiological and pharmacokinetic benefits in order to improve the effectiveness, tolerability, and patient compliance. This paper reviews their evolution, significance, and formulation factors (excipients and procedures), as well as their most important practical applications (inhaled insulin, liposomal preparations). The article presents the most important structures of microparticles (microspheres, microcapsules, coated pellets, etc.), interpreted with microscopic images too. The most significant production processes (spray drying, extrusion, coacervation, freeze-drying, microfluidics), the drug release mechanisms, and the commonly used excipients, the characterization, and the novel drug delivery systems (microbubbles, microsponges), as well as the preparations used in therapy are discussed in detail.

Researches on Preparation of Photosan Loaded Magnetic Silica Anoparticles and their Anti-Tumor Effects in Photodynamic Therapy

2012 ◽  
Vol 622-623 ◽  
pp. 821-826
Author(s):  
Yu Wen ◽  
Xiao Feng Deng ◽  
Liang Liang Liu ◽  
Shu Yun Shi ◽  
Li Xiong
Keyword(s):  
Drug Delivery ◽  
Photodynamic Therapy ◽  
Drug Delivery System ◽  
Delivery System ◽  
Sol Gel ◽  
Haematoporphyrin Derivative ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Good Biocompatibility ◽  
Low Solubility

Photodynamic therapy (PDT) is an effective, noninvasive and nontoxic therapeutics for cancer and some other diseases. It is becoming a alternative of traditional therapeutics for cancers. But the efficacy of PDT was restricted by insufficient selectivity and low solubility. In this study, novel multifunctional silica-based magnetic nanoparticles were prepared as targeting drug delivery system to achieve higher specificity and better solubility. Haematoporphyrin derivative (photosan) was used as photosensitizer. Magnetite nanoparticles (Fe3O4) and photosan were incorporated in silica nanoparticles by microemulsion and sol-gel methods. The prepared nanoparticles were characterized by X-ray diffraction, and transmission electron microscopy. The nanoparticles possessed good biocompatibility and could cause remarkable photodynamic anti-tumor effects. These suggested that photosan-Fe3O4 nanoparticles had great potential as effective drug delivery system in targeting photodynamic therapy.

scholarly journals Enzymatically triggered rupture of polymersomes

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1014-1020 ◽  
Author(s):  
Woo-Sik Jang ◽  
Seung Chul Park ◽  
Ellen H. Reed ◽  
Kevin P. Dooley ◽  
Samuel F. Wheeler ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Glucose Oxidase

Polymersomes are robust vesicles made from di-block co-polymers. We have engineered a two step enzymatic cascade to trigger the release of contents from polymersomes, in which extravesicular glucose oxidase makes hydrogen peroxide, when then penetrates the membrane and is converted by entrapped catalase to oxygen, leading to vesicle failure.

Three-Dimensional Holey-Graphene Architectures for Highly Sensitive Enzymatic Electrochemical Determination of Hydrogen Peroxide

2019 ◽  
Vol 19 (11) ◽  
pp. 7404-7409 ◽  
Author(s):  
Aihua Jing ◽  
Gaofeng Liang ◽  
Hao Shi ◽  
Yixin Yuan ◽  
Quanxing Zhan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Hydrogen Peroxide ◽  
Graphene Oxide ◽  
Three Dimensional ◽  
Electrochemical Determination ◽  
High Specific Surface Area ◽  
3D Graphene ◽  
Practical Applications ◽  
Transmission Electron ◽  
Mild Defect

Three-dimensional (3D) graphene with high specific surface area, excellent conductivity and designed porosity is essential for many practical applications. Herein, holey graphene oxide with nano pores was facilely prepared via a convenient mild defect-etching reaction and then fabricated to 3D nanostructures via a reduction method. Based on the 3D architectures, a novel enzymatic hydrogen peroxide sensor was successfully fabricated. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize the 3D holey graphene oxide architectures (3DHGO). Cyclic voltammetry (CV) was used to evaluate the electrochemical performance of 3DHGO at glassy carbon electrode (GCE). Excellent electrocatalytic activity to the reduction of H2O2 was observed, and a linear range of 5.0×10-8~5.0×10-5 M with a detection limit of 3.8×10-9 M was obtained. These results indicated that 3DHGO have potential as electrochemical biosensors.

scholarly journals A GREEN APPROACH FOR THE SYNTHESIS OF DRUG DELIVERY SYSTEM, MESOPOROUS SILICA GRAFTED ACRYLAMIDE –β- CYCLODEXTRIN COMPOSITE, FOR THE CONTROLLED RELEASE OF CURCUMIN

2018 ◽  
Vol 11 (9) ◽  
pp. 372
Author(s):  
Manohar D Mullassery ◽  
Noeline B Fernandez ◽  
Surya R ◽  
Diana Thomas
Keyword(s):  
Drug Delivery ◽  
Controlled Delivery ◽  
X Ray Diffraction ◽  
In Vitro Biocompatibility ◽  
Green Approach ◽  
Solvent Free Conditions ◽  
Good Biocompatibility ◽  
Biocompatibility Study

Objective: The scope of the present study was the preparation and characterization of a novel composite acrylamide β-cyclodextrin grafted 3-aminopropyltriethoxysilane bentonite (AMCD-g-APSB), for the controlled delivery of curcumin (CUR).Methods: AMCD-g-APSB, was synthesized by solvent-free conditions using microwave irradiation. The structure and surface morphology of the composite was established using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermal analysis, etc.Results: The swelling percentage of the composite depends on both time and pH of the medium. The maximum swelling of the composite occurred at a pH of 7.4. The maximum drug encapsulation was occurring at a pH 3. About 96.5% of drug was loaded at pH 3. In vitro biocompatibility study was performed, and the result showed good biocompatibility of the composite in the concentration range 2.5–50 μg/ml.Conclusions: Drug delivery study of the composite proved that CUR could be successfully released in a controlled manner in the colon without much loses of the drug in the stomach.

scholarly journals A High-Speed Elliptic Curve Cryptography Processor for Teleoperated Systems Security

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Yong Xiao ◽  
Weibin Lin ◽  
Yun Zhao ◽  
Chao Cui ◽  
Ziwen Cai
Keyword(s):  
Elliptic Curve ◽  
Elliptic Curve Cryptography ◽  
High Speed ◽  
High Performance ◽  
Prime Field ◽  
Practical Applications ◽  
Cell Library ◽  
Cryptographic Algorithm ◽  
Human Operators ◽  
Key Length

Teleoperated robotic systems are those in which human operators control remote robots through a communication network. The deployment and integration of teleoperated robot’s systems in the medical operation have been hampered by many issues, such as safety concerns. Elliptic curve cryptography (ECC), an asymmetric cryptographic algorithm, is widely applied to practical applications because its far significantly reduced key length has the same level of security as RSA. The efficiency of ECC on GF (p) is dictated by two critical factors, namely, modular multiplication (MM) and point multiplication (PM) scheduling. In this paper, the high-performance ECC architecture of SM2 is presented. MM is composed of multiplication and modular reduction (MR) in the prime field. A two-stage modular reduction (TSMR) algorithm in the SCA-256 prime field is introduced to achieve low latency, which avoids more iterative subtraction operations than traditional algorithms. To cut down the run time, a schedule is put forward when exploiting the parallelism of multiplication and MR inside PM. Synthesized with a 0.13 um CMOS standard cell library, the proposed processor consumes 341.98k gate areas, and each PM takes 0.092 ms.

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