Study of Living Cell Distribution During Inkjet Printing of Bioink

2017 ◽  
Author(s):  
Mengyun Zhang ◽  
Srikumar Krishnamoorthy ◽  
Hongtao Song ◽  
Changxue Xu
Keyword(s):  
Inkjet Printing ◽  
Living Cell ◽  
Biomedical Applications ◽  
Cell Number ◽  
Experimental Results ◽  
Cell Distribution ◽  
Nozzle Orifice ◽  
Drop On Demand ◽  
The Mean ◽  
Cell Motion

Inkjet printing as a viable technology has been widely adapted for various biomedical applications, such as 3D biofabrication which utilizes the droplets generated from inkjet printing of bioink to build 3D viable structures. One of the key challenges is cell distribution which is cell number embedded per droplet/microsphere. It significantly affects the post-printing cell viability and proliferation. This paper focuses on the effect of excitation voltage on the living cell distribution during drop-on-demand inkjet printing of bioink containing living cells. The cell distribution results are compared under two different excitation voltages of 40V and 50V. The normal distribution is used to fit the experimental results. It is found that 1) at both 40V and 50V, the mean cell number of the experimental results is always smaller than the theoretical value due to cell motion inside the nozzle; and 2) the mean cell number errors are 3% at 40V and 18% at 50V, which is due to different ligament flow near the nozzle orifice. The resulting knowledge benefits efficient and effective fabrication of 3D cellular constructs with uniform cell distribution.

Phase Diagram of Pinch-off Behaviors During Drop-on-Demand Inkjetting of Alginate Solutions

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Changxue Xu ◽  
Zhengyi Zhang ◽  
Yong Huang ◽  
Heqi Xu
Keyword(s):  
Phase Diagram ◽  
Inkjet Printing ◽  
Biomedical Applications ◽  
Elastic Stress ◽  
Deborah Number ◽  
Process Conditions ◽  
Dimensionless Numbers ◽  
Drop On Demand ◽  
Capillary Stress ◽  
Complex Process

Viscoelastic polymer solutions have been extensively utilized in inkjet printing for a variety of biomedical applications. The pinch-off of viscoelastic jets is a key step toward the generation of droplets in inkjet printing. This complex process is governed by the interplay of four stresses, including inertial stress, capillary stress, viscous stress, and elastic stress. Depending on polymer solution properties and process conditions, four types of pinch-off phenomenon were observed during inkjetting of viscoelastic alginate solutions. In this study, material properties of alginate solutions with different concentrations have been characterized, and three dimensionless numbers (Ohnesorge number Oh, Deborah number De, and Weber number We) have been proposed to analyze different pinch-off behaviors. The phase diagram in terms of these three dimensionless numbers has been constructed to classify the regimes for different pinch-off types during inkjetting of viscoelastic alginate solutions. It is found that (1) at low De and Oh, the capillary stress is mainly balanced by the inertial stress, resulting in front pinching. (2) At medium De and low Oh, with the increase of We, the pinch-off type may change from front pinching to hybrid pinching to exit pinching. (3) At low Oh and high De, the capillary stress is mainly balanced by the elastic stress, resulting in exit pinching. (4) At high Oh and De, the viscoelastic effect is dominant. With the increase of We, middle pinching turns to be exit pinching due to the increase in the initial ligament diameter near the forming droplet.

Fabrication of 3D Temperature Sensor Using Magnetostrictive Inkjet Printhead

2020 ◽  
Vol 64 (5) ◽  
pp. 50405-1-50405-5
Author(s):  
Young-Woo Park ◽  
Myounggyu Noh
Keyword(s):  
Flexible Electronics ◽  
Inkjet Printing ◽  
Temperature Sensor ◽  
Computer Aided Design ◽  
Low Cost ◽  
Three Dimensional ◽  
Drop On Demand ◽  
Aided Design ◽  
Nanoparticle Ink ◽  
Inkjet Printhead

Abstract Recently, the three-dimensional (3D) printing technique has attracted much attention for creating objects of arbitrary shape and manufacturing. For the first time, in this work, we present the fabrication of an inkjet printed low-cost 3D temperature sensor on a 3D-shaped thermoplastic substrate suitable for packaging, flexible electronics, and other printed applications. The design, fabrication, and testing of a 3D printed temperature sensor are presented. The sensor pattern is designed using a computer-aided design program and fabricated by drop-on-demand inkjet printing using a magnetostrictive inkjet printhead at room temperature. The sensor pattern is printed using commercially available conductive silver nanoparticle ink. A moving speed of 90 mm/min is chosen to print the sensor pattern. The inkjet printed temperature sensor is demonstrated, and it is characterized by good electrical properties, exhibiting good sensitivity and linearity. The results indicate that 3D inkjet printing technology may have great potential for applications in sensor fabrication.

scholarly journals Assessing the Functional Properties of TiZr Nanotubular Structures for Biomedical Applications, through Nano-Scratch Tests and Adhesion Force Maps

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 900
Author(s):  
Maria Vardaki ◽  
Aida Pantazi ◽  
Ioana Demetrescu ◽  
Marius Enachescu
Keyword(s):  
Surface Roughness ◽  
Functional Properties ◽  
Bacterial Adhesion ◽  
Biomedical Applications ◽  
Adhesion Force ◽  
Roughness Parameters ◽  
Force Microscopy ◽  
Atomic Force ◽  
The Mean ◽  
Scratch Tests

In this work we present the results of a functional properties assessment via Atomic Force Microscopy (AFM)-based surface morphology, surface roughness, nano-scratch tests and adhesion force maps of TiZr-based nanotubular structures. The nanostructures have been electrochemically prepared in a glycerin + 15 vol.% H2O + 0.2 M NH4F electrolyte. The AFM topography images confirmed the successful preparation of the nanotubular coatings. The Root Mean Square (RMS) and average (Ra) roughness parameters increased after anodizing, while the mean adhesion force value decreased. The prepared nanocoatings exhibited a smaller mean scratch hardness value compared to the un-coated TiZr. However, the mean hardness (H) values of the coatings highlight their potential in having reliable mechanical resistances, which along with the significant increase of the surface roughness parameters, which could help in improving the osseointegration, and also with the important decrease of the mean adhesion force, which could lead to a reduction in bacterial adhesion, are providing the nanostructures with a great potential to be used as a better alternative for Ti implants in dentistry.

scholarly journals Contour Detection for Fibre of Preserved Szechuan Pickle Based on Dilated Convolution

2019 ◽  
Vol 9 (13) ◽  
pp. 2684 ◽  
Author(s):  
Hongyang Li ◽  
Lizhuang Liu ◽  
Zhenqi Han ◽  
Dan Zhao
Keyword(s):  
Edge Detection ◽  
State Of The Art ◽  
Contour Detection ◽  
Experimental Results ◽  
Contour Method ◽  
Class Differences ◽  
Dilated Convolution ◽  
The Mean ◽  
Art Performance

Peeling fibre is an indispensable process in the production of preserved Szechuan pickle, the accuracy of which can significantly influence the quality of the products, and thus the contour method of fibre detection, as a core algorithm of the automatic peeling device, is studied. The fibre contour is a kind of non-salient contour, characterized by big intra-class differences and small inter-class differences, meaning that the feature of the contour is not discriminative. The method called dilated-holistically-nested edge detection (Dilated-HED) is proposed to detect the fibre contour, which is built based on the HED network and dilated convolution. The experimental results for our dataset show that the Pixel Accuracy (PA) is 99.52% and the Mean Intersection over Union (MIoU) is 49.99%, achieving state-of-the-art performance.

Vibratory Feeding by Nonsinusoidal Vibration—Optimum Wave Form

1985 ◽  
Vol 107 (2) ◽  
pp. 188-195 ◽  
Author(s):  
S. Okabe ◽  
Y. Kamiya ◽  
K. Tsujikado ◽  
Y. Yokoyama
Keyword(s):  
Experimental Results ◽  
Wave Form ◽  
Velocity Wave ◽  
The Mean ◽  
Straight Lines ◽  
Vibratory Conveyor ◽  
Theoretical Results ◽  
Vibratory Feeding

This paper presents the conveying velocity on a vibratory conveyor whose track is vibrated by nonsinusoidal vibration. The velocity wave form of the vibrating track is approximated by six straight lines, and five distortion factors of the wave form are defined. Considering the modes of motion of the particle, the mean conveying velocity is calculated for various conditions. Referring to these results, the optimum wave form is clarified analytically. The theoretical results show that the mean conveying velocity is considerably larger than that of ordinary feeders if the proper conveying conditions are chosen. The theoretical results are confirmed by experimental results.

scholarly journals Adaptive Broadcasting Mechanism for Bandwidth Allocation in Mobile Services

2014 ◽  
Vol 2014 ◽  
pp. 1-14
Author(s):  
Gwo-Jiun Horng ◽  
Chi-Hsuan Wang ◽  
Chih-Lun Chou
Keyword(s):  
Analytical Model ◽  
Bandwidth Allocation ◽  
Data Dissemination ◽  
Data Access ◽  
Experimental Results ◽  
Bandwidth Utilization ◽  
Access Latency ◽  
The Mean ◽  
Access Efficiency ◽  
Broadcast Program

This paper proposes a tree-based adaptive broadcasting (TAB) algorithm for data dissemination to improve data access efficiency. The proposed TAB algorithm first constructs a broadcast tree to determine the broadcast frequency of each data and splits the broadcast tree into some broadcast wood to generate the broadcast program. In addition, this paper develops an analytical model to derive the mean access latency of the generated broadcast program. In light of the derived results, both the index channel’s bandwidth and the data channel’s bandwidth can be optimally allocated to maximize bandwidth utilization. This paper presents experiments to help evaluate the effectiveness of the proposed strategy. From the experimental results, it can be seen that the proposed mechanism is feasible in practice.

scholarly journals High-precision 3D inkjet technology for live cell bioprinting

2019 ◽  
Vol 5 (2) ◽  
pp. 27 ◽  
Author(s):  
Daisuke Takagi ◽  
Waka Lin ◽  
Takahiko Matsumoto ◽  
Hidekazu Yaginuma ◽  
Natsuko Hemmi ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Cell Types ◽  
Cell Number ◽  
Live Cell ◽  
Drop On Demand ◽  
Long Time ◽  
Spatial Positioning ◽  
Different Cell Types ◽  
Membrane Vibrations

In recent years, bioprinting has emerged as a promising technology for the construction of three-dimensional (3D) tissues to be used in regenerative medicine or in vitro screening applications. In the present study, we present the development of an inkjet-based bioprinting system to arrange multiple cells and materials precisely into structurally organized constructs. A novel inkjet printhead has been specially designed for live cell ejection. Droplet formation is powered by piezoelectric membrane vibrations coupled with mixing movements to prevent cell sedimentation at the nozzle. Stable drop-on-demand dispensing and cell viability were validated over an adequately long time to allow the fabrication of 3D tissues. Reliable control of cell number and spatial positioning was demonstrated using two separate suspensions with different cell types printed sequentially. Finally, a process for constructing stratified Mille-Feuille-like 3D structures is proposed by alternately superimposing cell suspensions and hydrogel layers with a controlled vertical resolution. The results show that inkjet technology is effective for both two-dimensional patterning and 3D multilayering and has the potential to facilitate the achievement of live cell bioprinting with an unprecedented level of precision.

scholarly journals Quantum Calculations to Estimate the Heat of Hydrogenation Theoretically

2020 ◽  
Author(s):  
Ali Amir Khairbek
Keyword(s):  
Unsaturated Hydrocarbon ◽  
Experimental Results ◽  
Basis Set ◽  
Good Linear ◽  
Complete Basis ◽  
Complete Basis Set ◽  
Complete Basis Set Limit ◽  
The Mean ◽  
Experimental Values ◽  
Linear Correlations

Standard enthalpies of hydrogenation of 29 unsaturated hydrocarbon compounds were calculated in the gas phase by CCSD(T) theory with complete basis set cc-pVXZ, where X = DZ, TZ, as well as by complete basis set limit extrapolation. Geometries of reactants and products were optimized at the M06-2X/6-31g(d) level. This M06-2X geometries were used in the CCSD(T)/cc-pVXZ//M06-2X/6-31g(d) and cc-pV(DT)Z extrapolation calculations. (MAD) the mean absolute deviations of the enthalpies of hydrogenation between the calculated and experimental results that range from 8.8 to 3.4 kJ mol−1 based on the Comparison between the calculation at CCSD(T) and experimental results. The MAD value has improved and decreased to 1.5 kJ mol−1 after using complete basis set limit extrapolation. The deviations of the experimental values are located inside the “chemical accuracy” (±1 kcal mol−1 ≈ ±4.2 kJ mol−1) as some results showed. A very good linear correlations between experimental and calculated enthalpies of hydro-genation have been obtained at CCSD(T)/cc-pVTZ//M06-2X/6-31g(d) level and CCSD(T)/cc-pV(DT)Z extrapolation levels (SD =2.11 and 2.12 kJ mol−1, respectively).

scholarly journals Reversible glomerular hypertrophy in adult patients with primary focal segmental glomerulosclerosis.

1997 ◽  
Vol 8 (11) ◽  
pp. 1668-1678
Author(s):  
K Nishimoto ◽  
H Shiiki ◽  
T Nishino ◽  
H Uyama ◽  
M Iwano ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Focal Segmental Glomerulosclerosis ◽  
Mesangial Cell ◽  
Mesangial Cells ◽  
Cell Number ◽  
Glomerular Hypertrophy ◽  
Control Subjects ◽  
Segmental Glomerulosclerosis ◽  
The Mean ◽  
Glomerular Tuft

The present study was performed to assess the pathogenetic role of glomerular hypertrophy in patients with primary focal segmental glomerulosclerosis (FSGS). We studied 14 patients with FSGS by morphometry. In seven patients, minimal change nephrotic syndrome (MCNS) was diagnosed on the first renal biopsy, but FSGS was diagnosed on the second biopsy (MCNS-FSGS group). Seven other patients with FSGS on the first biopsy underwent second biopsies while in remission (FSGS-R group). Biopsy results were compared with biopsies from 10 patients with MCNS and seven control subjects. Nonsclerotic glomeruli were examined. The mean glomerular tuft area, whole glomerular area, and number of mesangial cells were significantly increased in both biopsies from the MCNS-FSGS group and in the first biopsies obtained during the nephrotic stage of the FSGS-R group, compared with control subjects and patients with MCNS. Biopsies from FSGS patients in remission showed that the mean glomerular tuft area and number of mesangial cells were significantly decreased. The fractional extracellular matrix area (extracellular matrix area/glomerular tuft area) and mesangial cell density (mesangial cell number/glomerular tuft area) in FSGS during both nephrotic and remission stages were the same as those in control subjects and patients with MCNS. The present study suggests that glomerular hypertrophy precedes the development of glomerulosclerosis in FSGS and is reversible when patients are in remission. These features support the pathogenetic importance of glomerular hypertrophy in patients with primary FSGS.

Understanding Microdroplet Formations for Biomedical Applications

2008 ◽  
Author(s):  
Salil Desai ◽  
Anthony Moore ◽  
Benjamin Harrison ◽  
Jagannathan Sankar
Keyword(s):  
Drug Delivery ◽  
Sodium Chloride ◽  
Sodium Alginate ◽  
Calcium Chloride ◽  
Biomedical Applications ◽  
Tissue Scaffolds ◽  
Ambient Conditions ◽  
On Demand ◽  
Drop On Demand

This paper focuses on understanding microdroplet formation of sodium alginate biopolymer at various concentrations utilizing drop-on-demand inkjet technology. We investigate the effect of sodium chloride on the rheology of sodium alginate and derive a correlation between the size of the droplet versus the size of the microcapsules formed. Varying sizes of microcapsules are formed based on different concentrations of calcium chloride solvent. This understanding will give insight for fabricating drug delivery capsules and tissue scaffolds that are subject to extreme ambient conditions when interfaced with in-vivo environments.

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