multimodal-3d-printing-of-phantoms-to-simulate-biological-tissue

Multimodal 3D Printing of Phantoms to Simulate Biological Tissue

Biomedical optical imaging is playing an important role in diagnosis and treatment of various diseases. However, the accuracy and the reproducibility of ...

University of Science and Technology of China

Recently, interactions between one-dimensional structural stiffness of physical micro environments and cell biological process have been widely studied. However in previous studies, the influence of structural stiffness on biological process was coupled with the influence of micro fiber curvature. Therefore decoupling the influences of fiber curvature and structural stiffness on cell biological process is of prime importance. In this study, we proposed a novel cell culture substrate comprised of silicon nitride bridges whose structure stiffness can be regulated by altering the axial residual stress without changing material and geometry properties. Both theoretical calculations and finite element simulations were performed to study the influence of residual stress on structure stiffness of bridges. Then multi-positions AFM bending tests were implemented to measure local stiffness of a single micro bridge so as to verify our predictions. NIH/3T3 mouse fibroblast cells were cultured on our substrates to examine the feasibility of the substrate application for investigating cellular response to microenvironment with variable stiffness. The results showed that cells on the edge region near bridge ends were more spread, elongated and better aligned along the bridge axial direction than those on the bridge center region. The results suggest that cells can sense and respond to the differences of stiffness and stiffness gradient between the edge and the center region of the bridges, which makes this kind of substrates can be applied in some biomedical fields, such as cell migration and wound healing.

Stress stiffened silicon nitride micro bridges array as substrate with tunable stiffness for cell culture.

We propose a simple but efficient multiplex coaxial flow focusing (MCFF) process for single-step fabrication of multicompartment Janus microcapsules (MJMs) in a wide range of operating parameters. The produced MJMs consist of a multicompartmental core-shell structure with material compositions tunable in individual shell and core compartments. Potential applications of such a MJM agent are demonstrated in both benchtop and in vitro experiments. For the benchtop experiment, magnetic nanoparticles are loaded into one of the shell compartments and photopolymerized under ultraviolet light for controlled alignment and rotation of the microcapsules in a magnetic field. For the in vitro experiment, four different types of cells are encapsulated in the desired compartments of sodium alginate MJMs and co-cultured for seven days. By increasing the number of coaxial needles, we are also able to produce MJMs with three or more compartments. Our studies have shown that the proposed MCFF process is able to produce MJMs with desired material compositions and narrow size distribution. This process is inexpensive and scalable for mass production of various MJMs in its potential applications in biomedical imaging, drug delivery, and regenerative medicine.

Multiplex coaxial flow focusing for producing multicompartment Janus microcapsules with tunable material compositions and structural characteristics.

Phantoms simulating polarization characteristics of soft tissue play an important role in the development, calibration, and validation of diagnostic polarized imaging devices and of therapeutic strategy, in both laboratory and clinical settings. We propose to fabricate optical phantoms that simulate polarization characteristics of dense fibrous tissues by bonding electrospun polylactic acid (PLA) fibers between polydimethylsiloxane (PDMS) substrate with a groove. Increasing the rotational speed of an electrospinning collector helps improve the orientation of the electrospun fibers. The phantoms simulate the polarization characteristics of dense fibrous tissue of collagenous fibroma and healthy skin with high fidelity. Our experiments demonstrate the technical potential of using such phantoms for validation and calibration of polarimetric medical devices.

Article	Year
Stress stiffened silicon nitride micro bridges array as substrate with tunable stiffness for cell culture. Materials science & engineering. C, Materials for biological applications\| PubMed ID: 28415441	2017
Multiplex coaxial flow focusing for producing multicompartment Janus microcapsules with tunable material compositions and structural characteristics. Lab on a chip\| PubMed ID: 28812769	2017
Simulating orientation and polarization characteristics of dense fibrous tissue by electrostatic spinning of polymeric fibers. Biomedical optics express\| PubMed ID: 30800500	2019

Guangli Liu

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