Constructing Silk Fibroin-Based Three-Dimensional Microfluidic Devices via a Tape Mask-Assisted Multiple-Step Etching Technique

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

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Is Dialdehyde Chitosan a Good Substance to Modify Physicochemical Properties of Biopolymeric Materials?

International Journal of Molecular Sciences ◽

10.3390/ijms22073391 ◽

2021 ◽

Vol 22 (7) ◽

pp. 3391

Author(s):

Sylwia Grabska-Zielińska ◽

Alina Sionkowska ◽

Ewa Olewnik-Kruszkowska ◽

Katarzyna Reczyńska ◽

Elżbieta Pamuła

Keyword(s):

Mechanical Properties ◽

Tissue Engineering ◽

Physicochemical Properties ◽

Silk Fibroin ◽

Three Dimensional ◽

Microscopy Imaging ◽

Maximum Deformation ◽

One Step ◽

Chitosan Blends ◽

Fourier Transfer Infrared Spectroscopy

The aim of this work was to compare physicochemical properties of three dimensional scaffolds based on silk fibroin, collagen and chitosan blends, cross-linked with dialdehyde starch (DAS) and dialdehyde chitosan (DAC). DAS was commercially available, while DAC was obtained by one-step synthesis. Structure and physicochemical properties of the materials were characterized using Fourier transfer infrared spectroscopy with attenuated total reflectance device (FTIR-ATR), swelling behavior and water content measurements, porosity and density observations, scanning electron microscopy imaging (SEM), mechanical properties evaluation and thermogravimetric analysis. Metabolic activity with AlamarBlue assay and live/dead fluorescence staining were performed to evaluate the cytocompatibility of the obtained materials with MG-63 osteoblast-like cells. The results showed that the properties of the scaffolds based on silk fibroin, collagen and chitosan can be modified by chemical cross-linking with DAS and DAC. It was found that DAS and DAC have different influence on the properties of biopolymeric scaffolds. Materials cross-linked with DAS were characterized by higher swelling ability (~4000% for DAS cross-linked materials; ~2500% for DAC cross-linked materials), they had lower density (Coll/CTS/30SF scaffold cross-linked with DAS: 21.8 ± 2.4 g/cm3; cross-linked with DAC: 14.6 ± 0.7 g/cm3) and lower mechanical properties (maximum deformation for DAC cross-linked scaffolds was about 69%; for DAS cross-linked scaffolds it was in the range of 12.67 ± 1.51% and 19.83 ± 1.30%) in comparison to materials cross-linked with DAC. Additionally, scaffolds cross-linked with DAS exhibited higher biocompatibility than those cross-linked with DAC. However, the obtained results showed that both types of scaffolds can provide the support required in regenerative medicine and tissue engineering. The scaffolds presented in the present work can be potentially used in bone tissue engineering to facilitate healing of small bone defects.

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Comparative Study of Silk Fibroin-Based Hydrogels and Their Potential as Material for 3-Dimensional (3D) Printing

Molecules ◽

10.3390/molecules26133887 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3887

Author(s):

Watcharapong Pudkon ◽

Chavee Laomeephol ◽

Siriporn Damrongsakkul ◽

Sorada Kanokpanont ◽

Juthamas Ratanavaraporn

Keyword(s):

3D Printing ◽

Silk Fibroin ◽

Biomedical Applications ◽

Mechanical Stability ◽

Three Dimensional ◽

Structure Stability ◽

3 Dimensional ◽

Critical Technology ◽

Box Structure ◽

High Degree

Three-dimensional (3D) printing is regarded as a critical technology in material engineering for biomedical applications. From a previous report, silk fibroin (SF) has been used as a biomaterial for tissue engineering due to its biocompatibility, biodegradability, non-toxicity and robust mechanical properties which provide a potential as material for 3D-printing. In this study, SF-based hydrogels with different formulations and SF concentrations (1–3%wt) were prepared by natural gelation (SF/self-gelled), sodium tetradecyl sulfate-induced (SF/STS) and dimyristoyl glycerophosphorylglycerol-induced (SF/DMPG). From the results, 2%wt SF-based (2SF) hydrogels showed suitable properties for extrusion, such as storage modulus, shear-thinning behavior and degree of structure recovery. The 4-layer box structure of all 2SF-based hydrogel formulations could be printed without structural collapse. In addition, the mechanical stability of printed structures after three-step post-treatment was investigated. The printed structure of 2SF/STS and 2SF/DMPG hydrogels exhibited high stability with high degree of structure recovery as 70.4% and 53.7%, respectively, compared to 2SF/self-gelled construct as 38.9%. The 2SF/STS and 2SF/DMPG hydrogels showed a great potential to use as material for 3D-printing due to its rheological properties, printability and structure stability.

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