scholarly journals 3D Superparamagnetic Scaffolds for Bone Mineralization under Static Magnetic Field Stimulation

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2834 ◽  
Author(s):  
Irina Alexandra Paun ◽  
Bogdan Stefanita Calin ◽  
Cosmin Catalin Mustaciosu ◽  
Mona Mihailescu ◽  
Antoniu Moldovan ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Magnetic Nanoparticle ◽  
Bone Mineralization ◽  
Three Dimensional ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Osteoblast Cells ◽  
Matrix Mineralization ◽  
Homogenous Distribution

We reported on three-dimensional (3D) superparamagnetic scaffolds that enhanced the mineralization of magnetic nanoparticle-free osteoblast cells. The scaffolds were fabricated with submicronic resolution by laser direct writing via two photons polymerization of Ormocore/magnetic nanoparticles (MNPs) composites and possessed complex and reproducible architectures. MNPs with a diameter of 4.9 ± 1.5 nm and saturation magnetization of 30 emu/g were added to Ormocore, in concentrations of 0, 2 and 4 mg/mL. The homogenous distribution and the concentration of the MNPs from the unpolymerized Ormocore/MNPs composite were preserved after the photopolymerization process. The MNPs in the scaffolds retained their superparamagnetic behavior. The specific magnetizations of the scaffolds with 2 and 4 mg/mL MNPs concentrations were of 14 emu/g and 17 emu/g, respectively. The MNPs reduced the shrinkage of the structures from 80.2 ± 5.3% for scaffolds without MNPs to 20.7 ± 4.7% for scaffolds with 4 mg/mL MNPs. Osteoblast cells seeded on scaffolds exposed to static magnetic field of 1.3 T deformed the regular architecture of the scaffolds and evoked faster mineralization in comparison to unstimulated samples. Scaffolds deformation and extracellular matrix mineralization under static magnetic field (SMF) exposure increased with increasing MNPs concentration. The results are discussed in the frame of gradient magnetic fields of ~3 × 10−4 T/m generated by MNPs over the cells bodies.

scholarly journals Magnetically-driven 2D cells organization on superparamagnetic micromagnets fabricated by laser direct writing

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
I. A. Paun ◽  
C. C. Mustaciosu ◽  
M. Mihailescu ◽  
B. S. Calin ◽  
A. M. Sandu
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Superparamagnetic Nanoparticles ◽  
Cell Manipulation ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Tissue Integration ◽  
Cellular Attachment ◽  
Cell Organization ◽  
Topographical Cues

Abstract We demonstrate a proof of concept for magnetically-driven 2D cells organization on superparamagnetic micromagnets fabricated by laser direct writing via two photon polymerization (LDW via TPP) of a photopolymerizable superparamagnetic composite. The composite consisted of a commercially available, biocompatible photopolymer (Ormocore) mixed with 4 mg/mL superparamagnetic nanoparticles (MNPs). The micromagnets were designed in the shape of squares with 70 µm lateral dimension. To minimize the role of topographical cues on the cellular attachment, we fabricated 2D microarrays similar with a chessboard: the superparamagnetic micromagnets alternated with non-magnetic areas of identical shape and lateral size as the micromagnets, made from Ormocore by LDW via TPP. The height difference between the superparamagnetic and non-magnetic areas was of ~ 6 µm. In the absence of a static magnetic field, MNPs-free fibroblasts attached uniformly on the entire 2D microarray, with no preference for the superparamagnetic or non-magnetic areas. Under a static magnetic field of 1.3 T, the fibroblasts attached exclusively on the superparamagnetic micromagnets, resulting a precise 2D cell organization on the chessboard-like microarray. The described method has significant potential for fabricating biocompatible micromagnets with well-defined geometries for building skin grafts adapted for optimum tissue integration, starting from single cell manipulation up to the engineering of whole tissues.

scholarly journals Advanced Micro-Actuator/Robot Fabrication Using Ultrafast Laser Direct Writing and Its Remote Control

2020 ◽  
Vol 10 (23) ◽  
pp. 8563
Author(s):  
Sangmo Koo
Keyword(s):  
Three Dimensional ◽  
Processing Technique ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Precise Control ◽  
Two Photon ◽  
Non Invasive ◽  
Acoustic Control ◽  
Fs Laser ◽  
Invasive Control

Two-photon polymerization (TPP) based on the femtosecond laser (fs laser) direct writing technique in the realization of high-resolution three-dimensional (3D) shapes is spotlighted as a unique and promising processing technique. It is also interesting that TPP can be applied to various applications in not only optics, chemistry, physics, biomedical engineering, and microfluidics but also micro-robotics systems. Effort has been made to design innovative microscale actuators, and research on how to remotely manipulate actuators is also constantly being conducted. Various manipulation methods have been devised including the magnetic, optical, and acoustic control of microscale actuators, demonstrating the great potential for non-contact and non-invasive control. However, research related to the precise control of microscale actuators is still in the early stages, and in-depth research is needed for the efficient control and diversification of a range of applications. In the future, the combination of the fs laser-based fabrication technique for the precise fabrication of microscale actuators/robots and their manipulation can be established as a next-generation processing method by presenting the possibility of applications to various areas.

scholarly journals Use of Magnetic Field for Mitigating Gyroscope Errors for Indoor Pedestrian Positioning

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2592 ◽  
Author(s):  
Ming Ma ◽  
Qian Song ◽  
Yang Gu ◽  
Zhimin Zhou
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Inertial Navigation System ◽  
Three Dimensional ◽  
Calibration Method ◽  
Rate Of Change ◽  
Superior Performance ◽  
Novel Approach ◽  
Straight Line ◽  
Magnetometer Calibration

In the field of indoor pedestrian positioning, the improved Quasi-Static magnetic Field (iQSF) method has been proposed to estimate gyroscope biases in magnetically perturbed environments. However, this method is only effective when a person walks along straight-line paths. For other curved or more complex path patterns, the iQSF method would fail to detect the quasi-static magnetic field. To address this issue, a novel approach is developed for quasi-static magnetic field detection in foot-mounted Inertial Navigation System. The proposed method detects the quasi-static magnetic field using the rate of change in differences between the magnetically derived heading and the heading derived from gyroscope. In addition, to eliminate the distortions caused by system platforms and shoes, a magnetometer calibration method is developed and the calibration is transformed from three-dimensional to two-dimensional coordinate according to the motion model of a pedestrian. The experimental results demonstrate that the proposed method can provide superior performance in suppressing the heading errors with the comparison to iQSF method.

scholarly journals A scalable photonic computer solving the subset sum problem

2020 ◽  
Vol 6 (5) ◽  
pp. eaay5853 ◽  
Author(s):  
Xiao-Yun Xu ◽  
Xuan-Lun Huang ◽  
Zhan-Ming Li ◽  
Jun Gao ◽  
Zhi-Qiang Jiao ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Propagation Speed ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Time Consumption ◽  
Subset Sum Problem ◽  
Complete Problem ◽  
Strong Robustness ◽  
Subset Sum ◽  
Np Complete

The subset sum problem (SSP) is a typical nondeterministic-polynomial-time (NP)–complete problem that is hard to solve efficiently in time with conventional computers. Photons have the unique features of high propagation speed, strong robustness, and low detectable energy level and therefore can be promising candidates to meet the challenge. Here, we present a scalable chip built-in photonic computer to efficiently solve the SSP. We map the problem into a three-dimensional waveguide network through a femtosecond laser direct writing technique. We show that the photons sufficiently dissipate into the networks and search for solutions in parallel. In the case of successive primes, our approach exhibits a dominant superiority in time consumption even compared with supercomputers. Our results confirm the ability of light to realize computations intractable for conventional computers, and suggest the SSP as a good benchmarking platform for the race between photonic and conventional computers on the way toward “photonic supremacy.”

Three-dimensional staggered herringbone mixer fabricated by femtosecond laser direct writing

2013 ◽  
Vol 15 (2) ◽  
pp. 025601 ◽  
Author(s):  
Di Lin ◽  
Fei He ◽  
Yang Liao ◽  
Jintian Lin ◽  
Changning Liu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Three Dimensional ◽  
Direct Writing ◽  
Laser Direct Writing
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