Extraction and Characterization of Human Adipose Tissue-Derived Collagen: Toward Xeno-Free Tissue Engineering.

Background: Collagen is a key component of connective tissue and has been frequently used in the fabrication of medical devices for tissue regeneration. Human-originated collagen is particularly appealing due to its low immune response as an allograft biomaterial compared to xenografts and its ability to accelerate the regeneration process. Ethically and economically, adipose tissues available from liposuction clinics are a good resource to obtain human collagen.

FeS-incorporated 3D PCL scaffold improves new bone formation and neovascularization in a rat calvarial defect model.

199Three-dimensional (3D) scaffolds composed of various biomaterials, including metals, ceramics, and synthetic polymers, have been widely used to regenerate bone defects. However, these materials possess clear downsides, which prevent bone regeneration. Therefore, composite scaffolds have been developed to compensate these disadvantages and achieve synergetic effects.

3D-printed gelatin methacrylate (GelMA)/silanated silica scaffold assisted by two-stage cooling system for hard tissue regeneration.

Among many biomaterials, gelatin methacrylate (GelMA), a photocurable protein, has been widely used in 3D bioprinting process owing to its excellent cellular responses, biocompatibility and biodegradability. However, GelMA still shows a low processability due to the severe temperature dependence of viscosity. To overcome this obstacle, we propose a two-stage temperature control system to effectively control the viscosity of GelMA.

Preparation and Characterization of Human Adipose Tissue-Derived Extracellular Matrix, Growth Factors, and Stem Cells: A Concise Review.

Background: Human adipose tissue is routinely discarded as medical waste. However, this tissue may have valuable clinical applications since methods have been devised to effectively isolate adipose-derived extracellular matrix (ECM), growth factors (GFs), and stem cells. In this review, we analyze the literature that devised these methods and then suggest an optimal method based on their characterization results.

A cell-printing approach for obtaining hASC-laden scaffolds by using a collagen/polyphenol bioink.

In the cell-printing process, bioink has been considered as an extremely important component for successful fabrication of macroscale cell-laden structures. Bioink should be non-toxic, biocompatible, and printable. To date, alginate has been widely used as a whole or partial component of bioink because it is non-toxic to embedded cells and even it can provide good printability with rapid gelation under calcium ions.

Fabrication of hASCs-laden structures using extrusion-based cell printing supplemented with an electric field.

Unlabelled: In this study, we proposed a hybrid cell-printing technique that combines a conventional extrusion-based cell-printing process with an electrohydrodynamic jet. The electric field stabilized the extruded struts of cell-embedding-hydrogel and reduced the damage to dispensed cells caused by the high wall shear stress in the dispensing nozzle. The new cell-printing process was optimized in terms of various processing parameters, applied electric field strength, nozzle movement speed, and distance between the nozzle tip and working stage.

An Innovative Collagen-Based Cell-Printing Method for Obtaining Human Adipose Stem Cell-Laden Structures Consisting of Core-Sheath Structures for Tissue Engineering.

Three-dimensional (3D) cell printing processes have been used widely in various tissue engineering applications due to the efficient embedding of living cells in appropriately designed micro- or macro-structures. However, there are several issues to overcome, such as the limited choice of bioinks and tailor-made fabricating strategies. Here, we suggest a new, innovative cell-printing process, supplemented with a core-sheath nozzle and an aerosol cross-linking method, to obtain multilayered cell-laden mesh structure and a newly considered collagen-based cell-laden bioink.

Optimal size of cell-laden hydrogel cylindrical struts for enhancing the cellular activities and their application to hybrid scaffolds.

Biomedical scaffolds must be mechanically stable and highly porous three-dimensional (3D) structures to allow efficient cell-to-cell and cell-to-substrate interactions, induce blood vessel formation, and transfer oxygen, nutrients, and metabolic waste. A 3D cell-laden hybrid scaffold consisting of a combination of structural synthetic polymers and a cell-laden hydrogel is an outstanding biomedical scaffold due to its controllable mechanical properties, multiple cell loading, and homogeneous cell-distribution within the scaffold. But although this hybrid scaffold is better than conventional scaffolds, some issues must still be overcome.

Cell-printed hierarchical scaffolds consisting of micro-sized polycaprolactone (PCL) and electrospun PCL nanofibers/cell-laden alginate struts for tissue regeneration.

Hierarchical scaffolds consisting of micro-sized struts with inter-layered nanofibers between the struts are mechanically stable and biologically superior to conventionally fabricated rapid-prototyped scaffolds and electrospun nanofibers. However, although the hierarchical scaffolds overcome various disadvantages of conventional scaffolds, there are still some limitations, such as low cell migration in the thickness direction and non-homogeneous cell proliferation. To overcome these deficiencies, a new hierarchical scaffold supplemented with osteoblast-like cell (MG63)-laden alginate struts is proposed.

Regeneration of chronic tympanic membrane perforation using 3D collagen with topical umbilical cord serum.

Chronic tympanic membrane (TM) perforation is one of the most common otology complications. Current surgical management of TM perforation includes myringoplasty and tympanoplasty. The purpose of this study was to evaluate the efficacy and feasibility of three dimensional (3D) porous collagen scaffolds with topically applied human umbilical cord serum (UCS) for the regeneration of chronic TM perforation in guinea pigs.

Mastoid obliteration using three-dimensional composite scaffolds consisting of polycaprolactone/β-tricalcium phosphate/collagen nanofibers: an in vitro and in vivo study.

Two different composite scaffolds, solid-freeform-fabricated PCL/β-TCP supplemented with and without collagen nanofibers are fabricated. These scaffolds are evaluated whether a combination of collagen nanofibers with PCL/β-TCP can promote osteogenesis in a mastoid obliteration. To assess the effects of the cellular activities of osteoblast-like-cells (MG63), SEM images and MTT assays are conducted.

Fabrication of electrospun biocomposites comprising polycaprolactone/fucoidan for tissue regeneration.

In this study, we designed a new biocomposite comprising electrospun polycaprolactone (PCL)/fucoidan, in which the fucoidan has various beneficial biological functions, including anticoagulant, antiviral, and immunomodulatory activity. To obtain the composite scaffolds, a mixture of PCL and fucoidan was electrospun using various compositions (1, 2, 3, and 10 wt.%) of fucoidan powders.

Three-dimensional hierarchical composite scaffolds consisting of polycaprolactone, β-tricalcium phosphate, and collagen nanofibers: fabrication, physical properties, and in vitro cell activity for bone tissue regeneration.

β-Tricalcium phosphate (β-TCP) and collagen have been widely used to regenerate various hard tissues, but although Bioceramics and collagen have various biological advantages with respect to cellular activity, their usage has been limited due to β-TCP's inherent brittleness and low mechanical properties, along with the low shape-ability of the three-dimensional collagen. To overcome these material deficiencies, we fabricated a new hierarchical scaffold that consisted of a melt-plotted polycaprolactone (PCL)/β-TCP composite and embedded collagen nanofibers. The fabrication process was combined with general melt-plotting methods and electrospinning.