3D Cell Structures Research Articles

3D cellular structures and co-cultures formed through the contactless magnetic manipulation of cells on adherent surfaces.

A magnet array is employed to manipulate diamagnetic cells that are contained in paramagnetic medium to demonstrate for the first time the contactless bioprinting of three-dimensional (3D) cellular structures and co-cultures of breast cancer MCF-7 and endothelial HUVEC at prescribed locations on tissue culture treated well plates. Sequential seeding of different cell lines and the spatial displacement of the magnet array creates co-cultured cellular structures within a well without using physically intrusive well inserts. Both monotypic and co-culture experiments produce morphologically rich 3D cell structures that are otherwise absent in regular monolayer cell cultures. The magnetic contactless bioprinting of cells provides further insight into cell behaviour, invasion strategies and transformations that are useful for potential applications in drug screening, 3D cell culture formation and tissue engineering.

Vascular Endothelial-Breast Epithelial Cell Coculture Model Created from 3D Cell Structures.

Endothelial cell interactions with normal and cancerous breast epithelial cells have been widely studied in tissue growth and development, as well as in angiogenesis and metastasis. Despite the understanding that 3D multicellular architecture is critical to the cell phenotype, 3D vascular structures have not yet been cocultured with 3D breast spheroids in vitro. The objective of this study was therefore to create a hierarchical, multiscale model of vascular endothelial-breast epithelial cell interactions in which both cell types were assembled into their 3D architectures. The model was successfully fabricated by adding preformed breast spheroids onto preformed endothelial tube-like networks. Through this model, we observed that breast spheroids maintain vascular tube-like networks. Over time, breast epithelial cells migrate out of the spheroid structure along the endothelial networks. This research shows that 3D cell structures serve as an important building block for creating multicellular coculture models to study physiologically relevant cell-cell interactions.

Silica with 3D Mesocellular Pore Structure Used as Support for Cobalt Fischer-Tropsch Catalyst

The typical MCM-41 and SBA-15 silica types were modified in order to expand their pores by addition of a swelling agent at mild conditions. The MCM- 41, SBA-15 and Pore-expanded (PE) mesoporous silicas, i.e., PE-SBA-15 and PE-MCM-41 were synthesized by the atrane route and used as supports in the preparation of cobalt Fischer–Tropsch catalysts. The synthetized silicas presented a homogeneous morphology with narrow pore size distribution of 1D, 2D and 3D pore structures. The most interesting pore structure and size was presented by the PE-SBA-15 silica, which showed a 3D spherical cell structure of 30 nm diameter interconnected by small window pores of 7 nm of diameter. These supports were used in cobalt catalyst preparation. The characterization results showed that the pore structure and pore size affected the growth of cobalt oxide particles and cobalt-silica interaction. These factors played an important role on the cobalt dispersion and Degree of Reduction (DOR). Co/SBA-15 and Co/PE-SBA-15 catalysts presented similar physicochemical properties related with the Co3O4, but the pore size and structure of the support was different. All the catalysts were tested in Fischer-Tropsch reaction at close to industrial conditions. Co/PE-SBA-15 catalyst showed the best CO conversion and selectivity to long-chain hydrocarbons, results attributed to the higher degree of reduction of cobalt but mainly to the open network with 3D structure pores of the silica support which reduced the diffusion limitations of the reactants and products.

Novel Bioreactor-System for <i>In Situ</i>-Cultivation of Artificial Tissue

A bioreactor is a device simulating physiological environments for different biotechnological applications. In highly promising research fields like tissue engineering micro-sized bioreactors were utilized successfully promoting mammalian cells to grow and build 3D cell structures similar to in vivo environments. For any practical application and even for improved R&D it is necessary to generate and maintain a physiological environment over the whole cultivation period (hours, days or weeks, in case of artificial organs even up to months). Depending on the field of application physiological environments can comprise different parameters. In case of mammalian cell lines these parameters require a complex supply and monitoring system. Thus, we developed a semi-automated bioreactor-system for long-term cultivation of different mammalian cell types imitating physiological conditions. The system included detection and control of the following parameters: temperature, pH-value, gas concentration and the continuous supply with nutrients. A micro fluidic network was established enabling a high through-put cultivating system as bioreactor-system. The bioreactor-system consists of several micro-sized chambers in a microliter scale (the related article discussing the micro-sized chambers “Miniaturized Flow-Through Bioreactor for Processing and Testing in Pharmacology” by Boehme et al is published within this issue). The chambers were placed in a polymeric slide each with an individual medium supply and disposal. Every single chamber thus was connected to an individual syringe-based micro-pump setup and supplied by nutrients solution with a velocity of 100μl/h. The pH-value was observed optically and controlled via CO2 supply. All gas interchanges into every single chamber were realized via semi permeable membranes. The required temperature was adjusted via an appropriate custom-fit heating system utilizing MOSFETs allocated on an aluminum board along the slides. Two slides each were housed in a PMMA case. This bioreactor-system is a first prototype for larger systems aiming for the parallel operation of up to 100 micro-sized reaction chambers.

On Generating High-Quality Random Numbers

Random numbers are highly used in applications like computer simulation, gambling, statistical sampling and cryptography. Only a high-entropy random source can produce a better quality of random data. In this paper, we work on the generation of high-quality random numbers based on cellular automata (CA). We propose three-dimensional (3D) CA to generate a random sequence. We also propose various enhancements to CA-based pseudorandom number generator (CA-PRNG) and discuss its five variants by using two-dimensional (2D) and 3D CA. We analyze the switching between 2D and 3D CA for the same sequence to achieve high-quality randomness. We provide the architectures, CA rules and the algorithms for all the proposed variants with respect to 2D and 3D cell structures. We have done a software implementation of all the proposed variants and tested their produced sequences by using the internationally accepted standard for random numbers known as DIEHARD. The analysis of our results is made as per the recommendations of ANSI standards. A very similar criteria are applied to compare all the methods. Based on our results we are able to find the best CA-PRNG for producing high-quality random sequence.

Two-Photon Microscopy of the Mouse Peripheral Cornea Ex Vivo.

To investigate the 3-dimensional (3D) cell and extracellular matrix (ECM) structure of mouse peripheral corneas in normal and corneal neovascularization tissues using 2-photon microscopy (TPM) based on both intrinsic and extrinsic moxifloxacin contrasts. Peripheral corneas in freshly enucleated mouse eyes were imaged by TPM based on both intrinsic and extrinsic contrasts. Intrinsic autofluorescence and second harmonic generation were used to image cells and ECM collagen, respectively. Moxifloxacin ophthalmic solution was applied to image cells. The peripheral cornea, limbus, and sclera were imaged in 3D. In addition to normal mice, mouse models of suture-induced corneal neovascularization were imaged to visualize changes in the microstructure. Complex 3D cell and ECM structures in the cornea, limbus, and sclera were visualized by TPM. TPM images based on intrinsic contrasts visualized both cell and ECM structures, and TPM images based on moxifloxacin visualized cell structures with enhanced contrast. On the limbus side of the mouse peripheral cornea, TPM images visualized the vasculature in the limbus, the trabecular meshwork/Schlemm canal, iris, and ciliary body. On the scleral side, TPM images visualized cell and ECM structures in the sclera and multiple cell layers below the sclera. TPM images of the peripheral cornea in the corneal neovascularization condition visualized the extension of vasculature from the limbus to the cornea. TPM imaging based on both intrinsic and external moxifloxacin contrasts visualized detailed 3D cell and ECM microstructures in the mouse peripheral cornea. TPM based on moxifloxacin might be advantageous for studying cell structures by enhancing image contrast.

Interaction of microtubules with the actin cytoskeleton via cross-talk of EB1-containing +TIPs and γ-actin in epithelial cells.

Actin microfilaments and microtubules are both highly dynamic cytoskeleton components implicated in a wide range of intracellular processes as well as cell-cell and cell-substrate interactions. The interactions of actin filaments with the microtubule system play an important role in the assembly and maintenance of 3D cell structure. Here we demonstrate that cytoplasmic actins are differentially distributed in relation to the microtubule system. LSM, 3D-SIM, proximity ligation assay (PLA) and co-immunoprecipitation methods applied in combination with selective depletion of β- or γ-cytoplasmic actins revealed a selective interaction between microtubules and γ-, but not β-cytoplasmic actin via the microtubule +TIPs protein EB1. EB1-positive comet distribution analysis and quantification have shown more effective microtubule growth in the absence of β-actin. Our data represent the first demonstration that microtubule +TIPs protein EB1 interacts mainly with γ-cytoplasmic actin in epithelial cells.

Automation Highlights from the Literature

Automation Highlights from the Literature

Observation of the Oil Content of Fried Lotus (Nelumbo nuciferaGaertn.) Root Slices by Confocal Laser Scanning Microscopy Based on Three-Dimensional Model

Microstructures of fried lotus root slices were observed using confocal laser scanning microscopy (CLSM) in fluorescent modes. The three-dimensional (3D) cell structure and morphology of samples were analyzed, for the first time, using 3D reconstructed fluorescent images to determine the cell morphology, oil location and content. Results show that oil was mainly located in the intercellular spaces, broken cells and voids created by the cutting operation, as well as in the wrinkles and distortions caused by the water leakage after frying, cell detachment, starch swelling and rapid dehydration of the first cell layer. Besides, the image stacks obtained by CLSM were processed independently to determine the oil-volume measurements using objective threshold selection. The 3D image data were used for quantitative characterization of oil content by calculating the oil volume. A good correlation between the CLSM results and normal analysis is obtained with the correlation coefficients of 0.892 and 0.875 in calibration and predication, respectively. This study demonstrated that CLSM could determine the oil location and content in fried snacks. Practical Application One of the most important quality parameters for the oil uptake of vacuum fried (VF) and atmospheric fried (AF) lotus root slices were determined and compared under the same frying condition. Microstructures of fried root slices of lotus (Nelumbo nucifera Gaertn.) were observed using CLSM in fluorescent modes. The three-dimensional (3D) cell structure and morphology of samples were analyzed, for the first time, using 3D reconstructed fluorescent images to determine the cell morphology, oil location and content. This optimal way of fried and fired condition was selected by the analytical results of CLSM.

Shape-controlled high cell-density microcapsules by electrodeposition

Cell encapsulation within alginate-poly-l-lysine (PLL) microcapsules has been developed to provide a miniaturized three-dimensional (3D) microenvironment with an aqueous core while promoting development of encapsulated cells into high cell-density structures. In this paper, a novel method for fabricating shape-controlled alginate-PLL microcapsules to construct 3D cell structures based on electrodeposition method is provided. Two-dimensional Ca-alginate cell-laden gel membranes were electrodeposited onto a micro-patterned electrode and further detached from the electrode. The PLL was coated onto the gel structures to form alginate-PLL complex as an outer shell and sodium citric solution was utilized to melt the internal alginate to achieve miniaturized 3D microcapsules (sphere, cuboid, and rod shape). By this proposed method, rat liver cells (RLC-18) formed multi-cellular aggregates with high cell-density after cultivation for 2weeks. Statement of SignificanceThe use of alginate-poly-l-lysine (PLL) microcapsules has shown great potential in fabricating 3D cell structures with high cell density. Despite their success related to their ability to provide a miniaturized microenvironment with an aqueous core, alginate-PLL microcapsules has drawback such as a limited shape-control ability. Because of the mechanism of Ca-induced alginate gel formation, it is still difficult to precisely control the gelation process to produce alginate-PLL microcapsules with specific shape. The present study provides an electrodeposition-based method to generate shape-controlled microcapsules for 3D cell structures. Sphere, cuboid, and rod shaped microcapsules of RLC-18 cells were produced for long-term culture to obtain desired morphologies of cell aggregates.

The variation in elastic modulus throughout the compression of foam materials

We present a comprehensive experimental study of the variation in apparent unloading elastic modulus of polymer (largely elastic), aluminium (largely plastic) and fibre-reinforced cement (quasi-brittle) closed-cell foams throughout uniaxial compression. The results show a characteristic “zero-yield-stress” response and thereafter a rapid increase in unloading modulus during the supposedly “elastic” regime of the compressive stress–strain curve. The unloading modulus then falls with strain due to the localised cell-wall yielding or failure in the pre-collapse stage and the progressive cell crushing in the plateau stage, before rising sharply during the densification stage which is associated with global cell crushing and foam compaction. A finite element model based on the actual 3D cell structure of the aluminium foam imaged by X-ray computed tomography (CT) predicts an approximately linear fall of elastic modulus from zero strain until a band of collapsed cells forms. It shows that the subsequent gradual decrease in modulus is caused by the progressive collapse of cells. The elastic modulus rises sharply after the densification initiation strain has been reached. However, the elastic modulus is still well below that of the constituent material even when the “fully” dense state is approached. This work highlights the fact that the unloading elastic modulus varies throughout compression and challenges the idea that a constant elastic modulus can be applied in a homogenised foam model. It is suggested that the most representative value of elastic modulus may be obtained by extrapolating the measured unloading modulus to zero strain.

Flow control for cell growth by movement of magnetic particles utilizing electromagnetic force

Three-dimensional (3D) cell structures are required to fabricate artificial organ. Inkjet technology is applied for fabrication of 3D cell structures in order to fabricate artificial organ and inve...

Redox-active Microcapsules as Drug Delivery System in Breast Cancer Cells and Spheroids

The purpose of our study was to develop new delivery systems for drugs effective against breast cancer by using biodegradable and biocompatible capsules. Redox-active microcapsules based on thiolated polymethacrylic acid (PMA) were employed. The interaction of these PMASH capsules with breast cancer cells and the mechanism of their internalization was investigated. PMASH biocompatibility was evaluated by MTT assay. To analyze their potential as drug carrier, we incorporated doxorubicin into the capsules. Confocal microscopy observations showed the presence of capsules inside the cells. Although some drug molecules still appeared co-localized with PMASH capsules, strong doxorubicin fluorescence was observed both in the cytoplasm and nucleus, indicating the disassembling of the capsule into PMASH-drug conjugate after internalization. These results were confirmed by both flow cytometry (time course of capsule uptake) and scanning electron microscopy. PMASH capsules were also internalized in 3D cell structures (spheroids) suggesting their potential use as drug delivery system for treatment of human diseases.

Effect of fibronectin-gelatin coating on 3D assembly of urothelial tissue constructs in vitro

Event Abstract Back to Event Effect of fibronectin-gelatin coating on 3D assembly of urothelial tissue constructs in vitro James P. Turner1, Julianne T. Jett2 and Jiro Nagatomi1 1 Clemson University, Bioengineering, United States 2 Clemson University, Biological Sciences, United States Introduction: Currently, limited solutions are available to regenerate the damaged urothelial layer caused by congenital bladder disorders, cancer of the bladder, and trauma. The goal of the present study is to develop a 3D urothelial tissue construct in vitro using the layer-by-layer cell assembly technique. Specifically, urothelial cells differentiated from human adipose-derived stem cells (hADSCs) were subjected to coating with alternating layers of fibronectin and gelatin prior to seeding and culturing. Cell morphology, phenotypic marker expression, and barrier function of the constructs were examined. Materials and Methods: For urothelial differentiation, hADSCs were cultured in defined keratinocyte serum-free media (KSFM) with supplementation. UROtsa cells were cultured in DMEM supplemented with 10% FBS and 1% Glutamax. Cells were coated via suspension in 9 alternating layers of fibronectin and gelatin at 0.04 mg/mL concentration. Coated cells were placed in either fibronectin-coated or fibronectin-gelatin multilayer-coated Transwell® inserts. To achieve an 8-layered tissue, hADSCs and UROtsa cells were seeded at 8.0x105 and 2.0x106 cells per well, respectively and cultured for at least 24 hours and up to 10 days. At the end of the prescribed time period, cells on insert membranes were fixed and sectioned for H&E staining, and immunostaining for CK-17, CK-20, UPIb, and ZO-1. Permeability across hADSC and UROtsa multilayers was measured using fluorescently labeled dextran (4 kDa, FITC; 70 kDa rhodamine B) and a microplate reader. Results and Discussion: Fibronectin-gelatin-coated, hADSC-derived urothelial cells on fibronectin-coated membrane showed aggregation after 24 hours indicating incomplete formation of a multilayer. In contrast, fibronectin-gelatin-coated UROtsa cells cultured on a fibronectin-gelatin-coated membrane displayed uniform layering and expression of tight junction protein ZO-1. Uncoated cells or cells seeded on an uncoated membrane exhibited a scattered appearance and less expression of ZO-1. Together, these results suggest that the fibronectin-gelatin coating facilitates cell-cell and membrane adhesion in UROtsa cells, which is critical for formation of 3D tissue constructs. In addition, permeability studies showed that there was significant difference in transcellular and paracellular transports between cell-seeded and empty culture inserts. However, results were similar between coated and uncoated hADSCs and UROtsa cells indicating that further maturation time may be necessary to create barrier function in the 3D multilayered cell constructs. Conclusion: The results of the present study provided evidence that the cellular microenvironment modified by ECM proteins would make a significant impact on the formation of 3D multilayered cell structure. Further experimentation is, however, needed to determine the effect of other parameters such as cell maturation and numbers of hADSC-derived urothelial cells on the barrier function of the multilayer construct, which is not only useful for regenerative medicine, but also as test platforms for drug screening and other experimentations in vitro. Keywords: Regenerative Medicine, Tissue Engineering, stem cell, 3D scaffold Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: New Frontier Oral Topic: Biomaterials in constructing tissue substitutes Citation: Turner JP, Jett JT and Nagatomi J (2016). Effect of fibronectin-gelatin coating on 3D assembly of urothelial tissue constructs in vitro. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.00319 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers James P Turner Julianne T Jett Jiro Nagatomi Google James P Turner Julianne T Jett Jiro Nagatomi Google Scholar James P Turner Julianne T Jett Jiro Nagatomi PubMed James P Turner Julianne T Jett Jiro Nagatomi Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. 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3D X-rays application for precision measurement of the cell structure of extruded polystyrene

While the thermal performance of existing insulation materials have been determined by blister gases, the thermal performance of future insulation materials will be dependent on the cell size and independent foam content as we use eco-friendly blister gases with a higher thermal conductivity. However, with the current technology we are only able to guess the whole cell size and independent foam content through SEM applied 2D fragmentary scanning but are still far from the level of accurate cell structure data extraction. Under this situation, we utilized X-ray CT scanned 3D images to identify and shape the cell structure and proposed a method of inferring the whole distribution and independent foam content as accurately as possible. According to X-ray CT scanning images and SEM images, the shape was similar but according to tracer applied CT scanning images, the cell size distribution was 380∼400 pm within the range of the general insulation diameter distribution which had the highest reliability. As for extrusion foaming polystyrene, we need additional image processing to identify the independent foam content as its density is too low. So, it is recommended to raise the 3D cell structure completeness of XPS by improving the scanning accuracy.

Abstract 307: Determination of cell surface receptors CD44 and ErbB2 in NovaMatrix-3D - a 3D cell culture system

Abstract NovaMatrix-3D is an alginate-based cell culture system comprising an alginate foam matrix and an alginate immobilizing solution. Cells are first suspended in a solution of sodium alginate that is then applied to the foam. As the foam absorbs the cell suspension, gelation occurs in situ as calcium ions are donated from the foam which effectively cross-links the added alginate. A hydrogel forms in the pores of the foam entrapping the cells throughout the foam. Cell immobilization occurs at room temperature and physiological pH. Cell localization and multi-cellular structures formed within the transparent gel can be visualized using confocal microscopy after vital staining of cells within the gel. A unique aspect of using an alginate-based foam matrix for 3D cell growth is that cells and intact multi-cellular structures can be retrieved for further analysis by adding calcium chelating agents such as citrate that dissolve the gel. While the retrieval of intact 3D structures is a simple one-step process, it is of interest to evaluate if imaging of cellular receptors can be performed on cells within the 3D hydrogel. Results show that two cell receptors, CD44 and ErbB2, which are upregulated in SKOV-3 cells, can be detected and imaged on multicellular spheroids within the 3D alginate matrix. First, the receptor status of CD44 and ErbB2 were established for SKOV-3 cells growing as a traditional 2D cell culture using flow cytometry. SKOV-3 cells were then immobilized in NovaMatrix-3D using 150 μM RGD-alginate. The presence of RGD has previously been shown to accelerate cell proliferation and 3D cell growth of SKOV-3. After 12 days of growth, multicellular spheroids formed. The alginate hydrogel disks where then treated with FITC-anti-CD44, Pacific Blue-anti-CD44, or an FITC-conjugated Affibody directed against ErbB2. Hydrogel discs were also treated with relevant isotypic controls. Confocal microscopy was used to detect and image cellular receptors. The results show that the CD44 hyaluronan receptor could be detected and imaged using two different antibodies. Furthermore, another cell receptor, ErbB2, was visualized using an Affibody. Therefore, it may not be necessary to retrieve multi-cellular structures from NovaMatrix-3D in order to visualize and image cellular receptors. Traditionally immobilization of cells within an alginate hydrogel has been used to provide immune-protection to cells used in forming an artificial organ, for example pancreatic islets. However, the alginate hydrogel formed in NovaMatrix-3D is comprised of a lower alginate concentration, has a lower, non-saturating concentration of calcium as a cross-linking ion, and has a more open pore structure. These attributes facilitate influx of antibodies which allows in situ immuno-staining and imaging of cellular receptors. The ability to stain cellular receptors on 3D cell structures within an alginate hydrogel make NovaMatrix-3D an even more versatile cell culture system. Citation Format: John Michael Dornish, Therese Andersen. Determination of cell surface receptors CD44 and ErbB2 in NovaMatrix-3D - a 3D cell culture system. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 307. doi:10.1158/1538-7445.AM2015-307

3D printing of layered brain-like structures using peptide modified gellan gum substrates

The brain is an enormously complex organ structured into various regions of layered tissue. Researchers have attempted to study the brain by modeling the architecture using two dimensional (2D) in vitro cell culturing methods. While those platforms attempt to mimic the in vivo environment, they do not truly resemble the three dimensional (3D) microstructure of neuronal tissues. Development of an accurate in vitro model of the brain remains a significant obstacle to our understanding of the functioning of the brain at the tissue or organ level. To address these obstacles, we demonstrate a new method to bioprint 3D brain-like structures consisting of discrete layers of primary neural cells encapsulated in hydrogels. Brain-like structures were constructed using a bio-ink consisting of a novel peptide-modified biopolymer, gellan gum-RGD (RGD-GG), combined with primary cortical neurons. The ink was optimized for a modified reactive printing process and developed for use in traditional cell culturing facilities without the need for extensive bioprinting equipment. Furthermore the peptide modification of the gellan gum hydrogel was found to have a profound positive effect on primary cell proliferation and network formation. The neural cell viability combined with the support of neural network formation demonstrated the cell supportive nature of the matrix. The facile ability to form discrete cell-containing layers validates the application of this novel printing technique to form complex, layered and viable 3D cell structures. These brain-like structures offer the opportunity to reproduce more accurate 3D in vitro microstructures with applications ranging from cell behavior studies to improving our understanding of brain injuries and neurodegenerative diseases.

Blind Depth-variant Deconvolution of 3D Data in Wide-field Fluorescence Microscopy.

This paper proposes a new deconvolution method for 3D fluorescence wide-field microscopy. Most previous methods are insufficient in terms of restoring a 3D cell structure, since a point spread function (PSF) is simply assumed as depth-invariant, whereas a PSF of microscopy changes significantly along the optical axis. A few methods that consider a depth-variant PSF have been proposed; however, they are impractical, since they are non-blind approaches that use a known PSF in a pre-measuring condition, whereas an imaging condition of a target image is different from that of the pre-measuring. To solve these problems, this paper proposes a blind approach to estimate depth-variant specimen-dependent PSF and restore 3D cell structure. It is shown by experiments on that the proposed method outperforms the previous ones in terms of suppressing axial blur. The proposed method is composed of the following three steps: First, a non-parametric averaged PSF is estimated by the Richardson Lucy algorithm, whose initial parameter is given by the central depth prediction from intensity analysis. Second, the estimated PSF is fitted to Gibson's parametric PSF model via optimization, and depth-variant PSFs are generated. Third, a 3D cell structure is restored by using a depth-variant version of a generalized expectation-maximization.

AM技術を応用した金属製三次元セル構造の作成方法(<特集>3Dプリンタで注目されるAdditive Manufacturingの新潮流)

AM技術を応用した金属製三次元セル構造の作成方法(<特集>3Dプリンタで注目されるAdditive Manufacturingの新潮流)

Precision printing of gelatin utilizing electrostatic inkjet

The precision printing of biomaterials is essential for fabricating bio devices, and two-dimensional (2D) and three-dimensional (3D) cell structures. To fabricate 3D cell structure artificially, biomaterials should be installed between cells to support the gravity force of cells. In general, the viscosity of ink from biomaterials is relatively high. An electrostatic inkjet is used for the bioprinting of cells and biomaterials because it has good merits, i.e., high printing resolution and good capability to eject highly viscous ink. In this paper, gelatin, an important biomaterial is printed using an electrostatic inkjet. The width of the finest printed line is 6 µm. The precisely printed line can be used as a scaffold of living cells.