CellScale User Publication Highlight: Multiparametric Analysis of Tissue Spheroids

CellScale User Publication Highlight: Multiparametric Analysis of Tissue Spheroids

Tissue spheroids (TS) are being increasingly recognized as a powerful tool to create 3D human tissues. This complex cell and matrix composition is formed without scaffolds and can recapitulate the architecture and functional characteristics of native tissue. TS is extremely attractive as an alternative to animal testing in drug discovery and cancer research, however the fabrication of TS is widely diverse and does not follow a protocol that tracks spheroids size, growth and morphology over time. Here, Dr. Elena Bulanova and her team at the Laboratory for Biotechnology Research 3D Bioprinting Solutions in Russia has presented a straightforward procedure for fabricating and characterizing TS with defined properties and uniform predictable geometry. Her solution applies to different cell types and uses non-adhesive technology.
In their comprehensive study,  they have established that different cell types contributed to different growth patterns, where diameter and roundness parameters were tracked over time up to 9 days. TS morphology and viability were also found to be cell-type specific. Using the CellScale MicroTester, the team could evaluate the mechanical properties of TS and discovered them to vary significantly depending on cell type. The image below shows the setup of the MicroTester for the experiment and the graph below shows the Elastic Modulus of TS for different cell types and maturation time.

 

To read the full article, click here: https://doi.org/10.1002/biot.201900217

To read more about Dr. Bulanova’s research, click here: https://scholar.google.com/citations?user=V8gGRS0AAAAJ&hl=en

To read about mechanical testing of miniaturized needle arrays, click here.

CellScale User Publication Highlight: Promoting Maturation of hiPSC-derived Cardiomyocytes with Re-entrant Waves

CellScale User Publication Highlight: Promoting Maturation of hiPSC-derived Cardiomyocytes with Re-entrant Waves

Human-induced pluripotent stem cell (hiPSC) derived cardiomyocytes present themselves as an abundant resource for tissue engineering, drug screening and regenerative-medicine applications. However, they are available in an immature state, mimicking poorly the physiology of adult human cardiomyocytes. There are methods to increase the maturation and function of hiPSC-derived cardiomyocytes, although each of them presents shortfalls such as heavy metal poisoning and difficulty in mass stimulation. Dr. Li Liu, Y Sawa and their team and her team from Osaka University Graduate School of Medicine has published in Nature journal an article about their success in creating a platform capable of promoting rapid formation of hiPSC-derived cardiomyocytes into 3D self-organized tissue rings (SOTRs). In addition, they constructed a mathematical model to characterize the long-term behavior of the reentrant waves (ReW) within the cardiac tissue. The image above shows the schematics and actual images of the SOTRs from their experiment.

The SOTRs created were studied for beating frequency and ReW speed in relation to the ring diameter. They were also analyzed for specific gene expression, Ca2+ handling properties, oxygen-consumption rate and contractile force. To measure the contractile force, the team used the CellScale MicroTester in a 3-point bending test setup while immersed in a temperature-controlled water bath. The graph below shows the maximum contraction force at 2 different ReWs.

To read the full article, click here: https://doi.org/10.1038/s42003-020-0853-0

To read more about Dr. Liu’s research, click here: http://www.dma.jim.osaka-u.ac.jp/view?l=en&u=10008971&f1=I&f2=I90&sm=field&sl=en&sp=1

To read about another publication with the CellScale MicroTester, click here.

CellScale User Publication Highlight: A Wireless Smart Bandage with Miniaturized Needle Arrays

CellScale User Publication Highlight: A Wireless Smart Bandage with Miniaturized Needle Arrays

Patients with type II diabetes experience chronic wounds, a condition where wounds fail to self-heal after 3 months. Physiological processes leading to wound healing such as vascularization are disrupted and biofilms form on the wound bed that are resistant to topical antibiotics treatment. Dr. Ali Tamayol and his team from the University of Nebraska-Lincoln published a study in the journal of Advanced Functional Materials about a wearable and programmable bandage that can deliver vital drugs into the deeper layers of the wound bed, past the biofilm. They achieve this with miniaturized needle arrays (MNAs) that induce minimal pain and inflammation compared to other invasive methods. The programmable portion allows a physician to remotely administer therapeutics as needed.

To fabricate the MNAs, the team used a multimaterial 3D printer that created hollow MNAs out of a biocompatible resin. Needle spacings, needle lengths, base sizes and opening diameters could be customized for various wound types. To investigate the mechanical properties of the printed needles (more specifically its breakage force), compression force testing with the CellScale UniVert was done at 200N. This same instrument was also employed to investigate penetration and retraction force of the MNAs on pig skin (see image below), as well as the bonding strength of the MNA island to a PDMS substrate holding microchannels for drug delivery.

To read the full article about their design, fabrication and tests, click here: https://doi.org/10.1002/adfm.201905544
To read more about Dr. Tamayol’s research, click here: http://tamayol-lab.weebly.com/

To read about a low-cost, pilot-scale, melt-processing system, click here.

CellScale User Publication Highlight: A Low-cost, Pilot-scale, Melt Processing System

CellScale User Publication Highlight: A Low-cost, Pilot-scale, Melt Processing System

Melt processing is a manufacturing technique to create plastics with different size, shape and function. It is a continuous manufacturing process  which improves the manufacturing speed and decreases costs to fabricate parts. In the biology field, components made by melt processing tend to have reduced microbial contamination because of the heat and pressure used in the process, making these devices safer. That being said, academic researchers tend to avoid melt-processing techniques despite the advantages because of the high cost of equipment, large volumes of materials for pilot-scale tests and the large dead-volume of high value research materials it would require. Dr. Jonathan Pokorski and David Wirth from the University of California present a study that yielded the schematics for a low-cost, low-volume injection-molding device. They have proven the device to successfully produce PLA, PLGA and PCL polymer composites at sub-milliliter volume, which caters to the sample size used in most academic labs.

To fabricate this benchtop injection molding instrument, the team repurposed 3D printer parts and a pneumatically-driven piston to fill specially machined aluminum molds (see image above). The polymer samples were manufactured with a variety of fillers and analyzed to see the distribution of those fillers. Analyses included Energy Dispersive X-Ray Spectroscopy (EDS) and mechanical tension testing with the CellScale UniVert. Below graphs show the mechanical properties (Elongation at Break, Young’s Modulus and Ultimate Strength) of injection molded composite materials at varying injection temperature compared to literature values of pristine PLA.

To read the full article, click here: https://doi.org/10.1016/j.polymer.2019.121802
To read more about Dr. Pokorski’s research, click here: https://profiles.ucsd.edu/jonathan.pokorski

To read about the effects of cyclic and shear stretch on inflammation and tissue formation, click here.

CellScale User Publication Highlight: The Effect of Cyclic Stretch and Shear Stretch on Inflammation and Tissue Formation

CellScale User Publication Highlight: The Effect of Cyclic Stretch and Shear Stretch on Inflammation and Tissue Formation

Resorbable synthetic scaffolds work to encourage tissue regeneration by allowing immune cells (e.g., macrophages) to infiltrate and attract tissue-producing cells that deposit new extracellular matrix (ECM). The deposited tissue is then remodeled to possess native-like structural and functional properties while the scaffold slowly degrades. However due to a mismatch between scaffold properties and its eventual mechanical loading, issues such as early stenosis and aneurysm occurs. Dr. Carlijn V. C. Bouten and her team at the Eindhoven University of Technology sought to uncover the underlying mechanism behind premature graft failure by creating a model that mimics the transient local inflammatory and biomechanical environments that drive scaffold-guided tissue regeneration. In particular, they looked at the mutual roles of physiological levels of shear stress and cyclic stretch on macrophage/fibroblast-mediated neotissue formation.

For their experiment setup, the team used polycaprolactone bis-urea (PCL-BU) which was electrospun into vascular scaffolds. The CellScale BioTester measured the stiffness through biaxial tensile testing prior to seeding them with human primary monocytes and (myo)fibroblasts. Next, they were cultured under healthy levels of shear stress for 20 days in their custom-built bioreactor before they were analyzed. The image above nicely summarizes the setup and initial results.

One interesting discovery in the paper was that shear stress played a role to reduce the increased stiffness of the scaffolds caused by cyclic stress. The graphs below highlight the Elastic Modulus in the axial and circumferential direction of the scaffolds. The combination of shear stress and cyclic stress produced a specimen with negligible change in stiffness when compared to a static model.

To read their full discovery and results, click here: http://dx.doi.org/10.1101/755157
To read more about Dr. Bouten’s research, click here: https://www.tue.nl/en/research/researchers/carlijn-bouten/

To read about axial torsion on the annulus fibrosus, click here.

CellScale User Publication Highlight: Hyperelastic Characterization of Mesh for Abdominal Hernia Repair

CellScale User Publication Highlight: Hyperelastic Characterization of Mesh for Abdominal Hernia Repair

When an abdominal hernia occurs, major surgery is often required to repair it and maintain the intact lining of the abdominal sac. However, the rate of surgical failure of this procedure is high along with a hernia recurrence rate of 24-50%. Prosthetic biomaterials providing reinforcement to the repair can reduce the hernia recurrence rate down to 4-24%, though there are new factors to consider such as biomechanical compatibility and material mechanical behavior. Dr. Georgina Carbajal de la Torre and her team from the Universidad Michoacana de San Nicolas de Hidalgo analyzed in this paper mechanical properties of materials used in abdominal wall repair and proposed a new mechanical model and methodology that more adequately describes such materials.

Using the CellScale UniVert, 2 commercial meshes underwent tension tests in longitudinal and transversal directions as shown above. Force-strain graphs were generated (shown below), and data was fitted into a five-parameter Mooney-Rivlin model. Further simulation can be obtained with finite element analysis.

The knowledge gained from this research can go toward proper selection of synthetic meshes for hernia repair based on a finer understanding of their mechanical behavior.

To read the full article, click here: https://doi.org/10.1557/adv.2019.399

To read more about Dr. Carbajal de la Torre’s research, click here: http://bit.ly/36ZqvMI

To read about a new testing method for viscoelasticity of biomaterials, click here.