Polyetheresterurethane Based Porous Scaffolds with Tailorable Architectures by Supercritical CO2 Foaming

MRS Advances ◽  
2020 ◽  
Vol 5 (45) ◽  
pp. 2317-2330
Author(s):  
Marc Behl ◽  
Muhammad Yasar Razzaq ◽  
Magdalena Mazurek-Budzyńska ◽  
Andreas Lendlein
Keyword(s):  
Pore Size ◽  
Treatment Options ◽  
Three Dimensional ◽  
Processing Parameters ◽  
Attractive Alternative ◽  
Porous Scaffolds ◽  
Potential Candidate ◽  
High Porosity ◽  
Average Pore ◽  
Scaffold Materials

AbstractPorous three-dimensional (3D) scaffolds are promising treatment options in regenerative medicine. Supercritical and dense-phase fluid technologies provide an attractive alternative to solvent-based scaffold fabrication methods. In this work, we report on the fabrication of poly-etheresterurethane (PPDO-PCL) based porous scaffolds with tailorable pore size, porosity, and pore interconnectivity by using supercritical CO2 (scCO2) fluid-foaming. The influence of the processing parameters such as soaking time, soaking temperature and depressurization on porosity, pore size, and interconnectivity of the foams were investigated. The average pore diameter could be varied between 100–800 μm along with a porosity in the range from (19 ± 3 to 61 ± 6)% and interconnectivity of up to 82%. To demonstrate their applicability as scaffold materials, selected foams were sterilized via ethylene oxide sterilization. They showed negligible cytotoxicity in tests according to DIN EN ISO 10993-5 and 10993-12 using L929 cells. The study demonstrated that the pore size, porosity and the interconnectivity of this multi-phase semicrystalline polymer could be tailored by careful control of the processing parameters during the scCO2 foaming process. In this way, PPDO-PCL scaffolds with high porosity and interconnectivity are potential candidate materials for regenerative treatment options.

scholarly journals Minimizing Drying Shrinkage and Enhancing Impermeability of Foam Concrete Modified with Epoxy Resin

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Jianqing Gong ◽  
Ke Li
Keyword(s):  
Surface Energy ◽  
Pore Size ◽  
Epoxy Resin ◽  
Average Pore Size ◽  
Drying Shrinkage ◽  
Maximum Level ◽  
High Porosity ◽  
Foam Concrete ◽  
Average Pore ◽  
Internal Pore Structure

Relatively high drying shrinkage and permeability were two of the major challenges associated with foam concrete (FC), primarily due to its high porosity nature. This study was aimed at reducing the drying shrinkage and improving the impermeability of FC by blending and modifying it with epoxy resin (EP). Extensive laboratory testing yielded an optimum content of 4.0% EP, corresponding to a minimum drying shrinkage rate of 1.47 mm/m, which was 48% lower than that of the unmodified FC. At this optimum dosage of 4.0% EP, the permeability pressure was at a maximum level of 1.4 MPa, whereas the permeability coefficient was at its lowest value of 0.75 × 10−9  mm/h. Internal pore structure and EP distribution were characterized using the scanning electron microscopy and indicated that a microgrid structure of the FC was formed internally, featuring an increase in the number of pores, a reduction in the average pore size, and a uniform pore size distribution. Similarly, surface energy measurements using the tensiometry method yielded maximum surface energy values at 4.0% EP content, which could be used to explain the reduced drying shrinkage and the enhanced impermeability characteristics of the modified FC.

OSTEOGENESIS OF ADIPOSE-DERIVED STEM CELLS ON THREE-DIMENSIONAL, MACROPOROUS GELATIN–HYALURONIC ACID CRYOGELS

2011 ◽  
Vol 23 (02) ◽  
pp. 127-133 ◽  
Author(s):  
Liao Han Tsung ◽  
Kun-Hung Chang ◽  
Jyh Ping Chen
Keyword(s):  
Stem Cells ◽  
Cell Proliferation ◽  
Hyaluronic Acid ◽  
Pore Size ◽  
Three Dimensional ◽  
Early Gene ◽  
Osteogenic Potential ◽  
Porous Scaffolds ◽  
Adipose Derived Stem Cells ◽  
Swelling Ratio

Aim. Macroporous sponge-like gelatin–hyaluronic acid (Gl–HA) scaffolds cross-linked by EDC were produced using cryogelation technology, which allows for the preparation of highly porous scaffolds without compromising their mechanical properties, and is a more cost-efficient process than freeze drying. The aim of this study is to evaluate the osteogenic potential of porcine adipose-derived stem cells (PADSCs) in GI–HA cryogel. Method. The character of the GI–HA cryogel was evaluated. The pore size and the microstructure were observed using scanning electron microscope (SEM). The swelling ratio was measured. The PADSCs were harvested and isolated from pig inguinal area. Then, the GI–HA cryogel was seeded with PADSCs. The cryogel/ASCs mixture was cultured in osteogenic medium for 0, 3, 7, 14, and 21 days. The cell proliferation was measured by MTS. The RT-PCR of specific osteogenic gene expression such as osteocalcin (OC), RUNX2 was used to assess the osteogenic ability. The SEM was used to observe the interaction between scaffold and cells. Energy dispersive spectrum (EDS) was used to analyze the mineralization around cells. Results. The pore size was variable between 200 and 369 μm. The swelling ratio was around 8.67 ± 1.669%. The cell proliferation was increasing along with the increase of induction periods. The expression of early gene of RUNX2 and late gene of OC mean that the PADSCs were differentiated well into osteoblasts within the cryogels. The SEM detailed that the PADSCs cell can proliferate well in the pore of GI–HA scaffold. The EDS also demonstrated the mineralization of PADSCs in GI–HA scaffold after induction. Conclusions. To conclude, the PADSCs can proliferate and differentiate well into osteoblasts in the three-dimensional, porous, GI–HA cryogel.

Hydroxyapatite Nano-Particles Coating on the Pore Surface Within Poly(DL-lactic-co-glycolic acid) Scaffold

2007 ◽  
Vol 334-335 ◽  
pp. 1237-1240 ◽  
Author(s):  
Jia Shen Li ◽  
Arthur F.T. Mak
Keyword(s):  
Pore Size ◽  
Glycolic Acid ◽  
Pore Wall ◽  
Nano Particles ◽  
Porous Scaffolds ◽  
High Porosity ◽  
Pore Surface ◽  
Plga Scaffold ◽  
Novel Method

This paper describes a novel method for coating hydroxyapatite (HA, Ca10(PO4)6(OH)2) nano-particles onto poly(DL-lactic-co-glycolic acid) (PLGA) scaffold. Paraffin micro-spheres were used as porogens to create porous scaffolds and as vehicles to transfer HA into PLGA scaffold. HA nano-particles / 50% ethanol suspension was mixed with paraffin micro-spheres. The paraffin micro-spheres / HA suspension were pressed together to form a paraffin scaffold. After it was dried, the HA was coated on the surface of the paraffin spheres. Then, PLGA solution was cast into the inter space among the paraffin micro-spheres and then the solvent was evaporated. Afterwards, the paraffin micro-spheres were dissolved and removed. PLGA scaffolds with controlled pore size, good interconnectivity and high porosity were obtained. The HA nano-particles were transferred from the paraffin surface to the surface of the pore wall throughout the PLGA scaffold.

Thermal Processing of Tissue Engineering Scaffolds

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Alisa Morss Clyne
Keyword(s):  
Tissue Engineering ◽  
Thermal Processing ◽  
Three Dimensional ◽  
Processing Parameters ◽  
High Pressure Processing ◽  
Porous Scaffolds ◽  
Tissue Engineering Scaffolds ◽  
Thermally Induced ◽  
Advantages And Disadvantages ◽  
Particulate Leaching

Tissue engineering requires complex three-dimensional scaffolds that mimic natural extracellular matrix function. A wide variety of techniques have been developed to create both fibrous and porous scaffolds out of polymers, ceramics, metals, and composite materials. Existing techniques include fiber bonding, electrospinning, emulsion freeze drying, solvent casting/particulate leaching, gas foaming/particulate leaching, high pressure processing, and thermally induced phase separation. Critical scaffold properties, including pore size, porosity, pore interconnectivity, and mechanical integrity, are determined by thermal processing parameters in many of these techniques. In this review, each tissue engineering scaffold preparation method is discussed, including recent advancements as well as advantages and disadvantages of the technique, with a particular emphasis placed on thermal parameters. Improvements on these existing techniques, as well as new thermal processing methods for tissue engineering scaffolds, will be needed to provide tissue engineers with finer control over tissue and organ development.

Preparation and Research of Porous KGM/ Collagen II Composite Cartilage Scaffolds

2013 ◽  
Vol 774-776 ◽  
pp. 949-953
Author(s):  
Ming Hua Huang ◽  
Hui Dong ◽  
Di Ru Xu ◽  
Duan Cheng Wang ◽  
Yong Shun Cui ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Pore Size ◽  
Raw Materials ◽  
Average Pore Size ◽  
Crosslinking Agent ◽  
Three Dimensional ◽  
Average Pore ◽  
Blending Method ◽  
Collagen Ii

KGM and Collagen II were selected as the main raw materials and ammonia served as the crosslinking agent to prepare the porous KGM / COLII composite cartilage scaffolds by blending method and freeze-drying method. The porosity, average pore size, compressive strength and water absorption were measured on the basis of the related standard. The scaffolds were characterized by SEM and XRD. The results show that the optimal program of preparing composite cartilage scaffolds is KGM (2g), COLII (1g), freeze temperature (-20 ° C) and ammonia (0.1 ml). The optimal cartilage scaffolds are porous three-dimensional network structures which the porosity is more than 90%; the average pore size is about 200μm; the compressive strength is about 0.75Mpa and the water absorption reaches up to 892%.

Conceptual design of three-dimensional scaffolds of powder-based materials for bone tissue engineering applications

2015 ◽  
Vol 21 (6) ◽  
pp. 716-724 ◽  
Author(s):  
Ramakrishna Vasireddi ◽  
Bikramjit Basu
Keyword(s):  
Tissue Engineering ◽  
Bone Tissue Engineering ◽  
Pore Size ◽  
Bone Tissue ◽  
Bone Repair ◽  
Three Dimensional ◽  
Porous Scaffolds ◽  
Content Type ◽  
Pore Sizes ◽  
Pore Size Distributions

Purpose – The purpose of this paper is to investigate the possibility to construct tissue-engineered bone repair scaffolds with pore size distributions using rapid prototyping techniques. Design/methodology/approach – The fabrication of porous scaffolds with complex porous architectures represents a major challenge in tissue engineering and the design aspects to mimic complex pore shape as well as spatial distribution of pore sizes of natural hard tissue remain unexplored. In this context, this work aims to evaluate the three-dimensional printing process to study its potential for scaffold fabrication as well as some innovative design of homogeneously porous or gradient porous scaffolds is described and such design has wider implication in the field of bone tissue engineering. Findings – The present work discusses biomedically relevant various design strategies with spatial/radial gradient in pore sizes as well as with different pore sizes and with different pore geometries. Originality/value – One of the important implications of the proposed novel design scheme would be the development of porous bioactive/biodegradable composites with gradient pore size, porosity, composition and with spatially distributed biochemical stimuli so that stem cells loaded into scaffolds would develop into complex tissues such as those at the bone–cartilage interface.

scholarly journals Tissue Engineering 3D Porous Scaffolds Prepared from Electrospun Recombinant Human Collagen (RHC) Polypeptides/Chitosan Nanofibers

2021 ◽  
Vol 11 (11) ◽  
pp. 5096
Author(s):  
Aipeng Deng ◽  
Yang Yang ◽  
Shimei Du
Keyword(s):  
Tissue Engineering ◽  
Three Dimensional ◽  
Great Promise ◽  
Porous Scaffolds ◽  
High Porosity ◽  
Engineering Applications ◽  
Nanofibrous Scaffolds ◽  
Human Collagen ◽  
Hierarchical Pore ◽  
Nih 3T3

Electrospinning, the only method that can continuously produce nanofibers, has been widely used to prepare nanofibers for tissue engineering applications. However, electrospinning is not suitable for preparing clinically relevant three-dimensional (3D) nanofibrous scaffolds with hierarchical pore structures. In this study, recombinant human collagen (RHC)/chitosan nanofibers prepared by electrospinning were combined with porous scaffolds produced by freeze drying to fabricate 3D nanofibrous scaffolds. These scaffolds exhibited high porosity (over 80%) and an interconnected porous structure (ranging from sub-micrometers to 200 μm) covered with nanofibers. As confirmed by the characterization results, these scaffolds showed good swelling ability, stability, and adequate mechanical strength, making it possible to use the 3D nanofibrous scaffolds in various tissue engineering applications. In addition, after seven days of cell culturing, NIH 3T3 was infiltrated into the scaffolds while maintaining its morphology and with superior proliferation and viability. These results indicated that the 3D nanofibrous scaffolds hold great promise for tissue engineering applications.

scholarly journals Three-Dimensional Printing of Curcumin-Loaded Biodegradable and Flexible Scaffold for Intracranial Therapy of Glioblastoma Multiforme

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 471
Author(s):  
Ruixiu Li ◽  
Yunmei Song ◽  
Paris Fouladian ◽  
Mohammad Arafat ◽  
Rosa Chung ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Glioblastoma Multiforme ◽  
Drug Delivery System ◽  
Delivery System ◽  
Treatment Options ◽  
Three Dimensional ◽  
Great Promise ◽  
Porous Scaffolds ◽  
3D Printed

A novel drug delivery system preventing Glioblastoma multiforme (GBM) recurrence after resection surgery is imperatively required to overcome the mechanical limitation of the current local drug delivery system and to offer personalised treatment options for GBM patients. In this study, 3D printed biodegradable flexible porous scaffolds were developed via Fused Deposition Modelling (FDM) three-dimensional (3D) printing technology for the local delivery of curcumin. The flexible porous scaffolds were 3D printed with various geometries containing 1, 3, 5, and 7% (w/w) of curcumin, respectively, using curcumin-loaded polycaprolactone (PCL) filaments. The scaffolds were characterised by a series of characterisation studies and in vitro studies were also performed including drug release study, scaffold degradation study, and cytotoxicity study. The curcumin-loaded PCL scaffolds displayed versatile spatiotemporal characteristics. The polymeric scaffolds obtained great mechanical flexibility with a low tensile modulus of less than 2 MPa, and 4 to 7-fold ultimate tensile strain, which can avoid the mechanical mismatch problem of commercially available GLIADEL wafer with a further improvement in surgical margin coverage. In vitro release profiles have demonstrated the sustained release patterns of curcumin with adjustable release amounts and durations up to 77 h. MTT study has demonstrated the great cytotoxic effect of curcumin-loaded scaffolds against the U87 human GBM cell line. Therefore, 3D printed curcumin-loaded scaffold has great promise to provide better GBM treatment options with its mechanical flexibility and customisability to match individual needs, preventing post-surgery GBM recurrence and eventually prolonging the life expectancy of GBM patients.

scholarly journals Formation of Water-Channel by Propylene Glycol into Polymer for Porous Materials

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 881
Author(s):  
Seong Ho Hong ◽  
Younghyun Cho ◽  
Sang Wook Kang
Keyword(s):  
Pore Size ◽  
Propylene Glycol ◽  
Metal Salt ◽  
Water Pressure ◽  
Water Channel ◽  
Porous Membrane ◽  
High Porosity ◽  
Pressure Treatment ◽  
Average Pore ◽  
Ft Ir

In this study, a porous membrane with a cellulose acetate (CA) matrix was fabricated using propylene glycol with a water pressure treatment without a metal salt as an additive. The water pressure treatment of the fabricated CA membrane with propylene glycol yielded nanopores. The nanopores were formed as the additives in the CA chains led to plasticization. The weakened chains of the parts where the plasticization occurred were broken by the water pressure, which generated the pores. Compared to the previous study with glycerin as an additive, the size of the hydration region was controlled by the number of hydrophilic functional groups. When water pressure was applied to the CA membrane containing propylene glycol as an additive, the hydration area was small, so it was effective to control the pore size and the number of nano pores than glycerin. In addition, the number of nanopores and pore size could be easily adjusted by the water pressure. The porosity of the membrane was increased owing to the trace amount of propylene glycol, confirmed by scanning electron microscopy (SEM) and porosimetry. The interaction between the CA and propylene glycol was verified by Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Consequently, it was the optimum composition to generate pores at the CA/propylene glycol 1:0.2 ratio, and porosity of 69.7% and average pore diameter of 300 nm was confirmed. Since it is a membrane with high porosity and nano sized pores, it is expected to be applied in various fields.

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