Preparation of porous collagen/hyaluronic acid hybrid scaffolds for biomimetic functionalization through biochemical binding affinity

Lee, Su Jin,Kim, So Yeon,Lee, Young Moo Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of Biomedical Materials Research Part B Vol. No.

<P>This study demonstrated the feasibility of introducing an avidin–biotin system to three-dimensional and highly porous scaffolds for the purpose of designing scaffolds that have binding affinity with bioactive molecules for various biomimetic modifications. Porous hybrid scaffolds composed of collagen and hyaluronic acid (HA) were prepared by a novel overrun process. The overrun-processed scaffolds showed a uniform dual-pore structure because of the injection of gas bubbles and ice recrystallization during the fabrication process and had a higher porosity than scaffolds prepared by a conventional freeze-drying method. The mechanical strength and biodegradation kinetics were controlled by the method of preparation and the composition of collagen/HA. Collagen/HA scaffolds did not show any significant adverse effects on cell viability even after 10 days of incubation. The fibroblasts cultured in the overrun-processed scaffolds were widely distributed and had proliferated on the surfaces of the macropores in the scaffolds, whereas the cells that were seeded in the freeze-dried scaffolds had attached mainly on the dense surface of the scaffolds. As the collagen content in the scaffolds increased, the cellular ingrowth into the inner pores of the scaffolds decreased because of the high affinity between the collagen and the cells. Measurements obtained via confocal microscopy revealed that the porous collagen/HA scaffolds could be functionalized with the biotin by incorporating avidin. Therefore, the present biotinylation approach may allow the incorporation of various bioactive molecules (DNA, growth factors, drug, peptide, etc) into the three-dimensional porous scaffolds. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2007</P>

3D printed mesh reinforcements enhance the mechanical properties of electrospun scaffolds

Nicholas W. Pensa,Andrew S. Curry,Paul P. Bonvallet,Nathan F. Bellis,Kayla M. Rettig,Michael S. Reddy,Alan W. Eberhardt,Susan L. Bellis 한국생체재료학회 2019 생체재료학회지 Vol.23 No.4

Background: There is substantial interest in electrospun scaffolds as substrates for tissue regeneration and repair due to their fibrous, extracellular matrix-like composition with interconnected porosity, cost-effective production, and scalability. However, a common limitation of these scaffolds is their inherently low mechanical strength and stiffness, restricting their use in some clinical applications. In this study we developed a novel technique for 3D printing a mesh reinforcement on electrospun scaffolds to improve their mechanical properties. Methods: A poly (lactic acid) (PLA) mesh was 3D-printed directly onto electrospun scaffolds composed of a 40:60 ratio of poly(ε-caprolactone) (PCL) to gelatin, respectively. PLA grids were printed onto the electrospun scaffolds with either a 6mm or 8mm distance between the struts. Scanning electron microscopy was utilized to determine if the 3D printing process affected the archtitecture of the electrospun scaffold. Tensile testing was used to ascertain mechanical properties (strength, modulus, failure stress, ductility) of both unmodified and reinforced electrospun scaffolds. An in vivo bone graft model was used to assess biocompatibility. Specifically, reinforced scaffolds were used as a membrane cover for bone graft particles implanted into rat calvarial defects, and implant sites were examined histologically. Results: We determined that the tensile strength and elastic modulus were markedly increased, and ductility reduced, by the addition of the PLA meshes to the electrospun scaffolds. Furthermore, the scaffolds maintained their matrix-like structure after being reinforced with the 3D printed PLA. There was no indication at the graft/tissue interface that the reinforced electrospun scaffolds elicited an immune or foreign body response upon implantation into rat cranial defects. Conclusion: 3D-printed mesh reinforcements offer a new tool for enhancing the mechanical strength of electrospun scaffolds while preserving the advantageous extracellular matrix-like architecture. The modification of electrospun scaffolds with 3D-printed reinforcements is expected to expand the range of clinical applications for which electrospun materials may be suitable.

Synergetic Cues of Bioactive Nanoparticles and Nanofibrous Structure in Bone Scaffolds to Stimulate Osteogenesis and Angiogenesis

Kim, Jung-Ju,El-Fiqi, Ahmed,Kim, Hae-Won American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.3

<P>Providing a nanotopological physical cue in concert with a bioactive chemical signal within 3D scaffolds, while it being considered a promising approach for bone regeneration, has yet to be explored. Here, we develop 3D porous scaffolds that are networked to be a nanofibrous structure and incorporated with bioactive glass nanoparticles (BGn) to tackle this issue. The presence of BGn and nanofibrous structure (BGn + nanofibrous) substantially increased the surface area, hydro-affinity and protein loading capacity of scaffolds. In particular, the BGn released Si and Ca ions to the levels known to be biologically effective, offering the bone scaffold an ability to deliver therapeutic ions. The mesenchymal stem cells (MSCs) from rats exhibited significantly accelerated adhesion events including cell anchorage, cytoskeletal extensions, and the expression of adhesion signaling molecules on the BGn/nanofibrous scaffolds. The cells gained a more rapid proliferation and migration (penetration) ability over 2 weeks within the BGn + nanofibrous scaffolds than within either nanofibrous,or BGn scaffolds. The osteogenesis of MSCs, as confirmed by the expressions of bone-associated genes and proteins) as well as the cellular mineralization was significantly stimulated by the BGn and nanofibrous topology in a synergistic manner. The behaviors of endothelial cells (HUVECs) including cell migration and tubule networking were also enhanced when influenced by the BGn and nanofibrous scaffolds (but more,by BGn than by nanofiber). A subcutaneous tissue implantation of the scaffolds further evidenced the in vivo stimulation of neo-blood vessel formation by the BGn + nanofibrous cues, suggesting the possible promising role in bone regeneration. Taken together, the therapeutic ions and nanofibrous topology implemented within 3D scaffolds are considered to play synergistic actions in osteogenesis and angiogenesis, implying the potential usefulness of the BGn + nanofibrous scaffolds for bone tissue engineering.</P>

The Effect of Bone Morphogenic Protein-2 (BMP-2)-Immobilizing Heparinized-Chitosan Scaffolds for Enhanced Osteoblast Activity

윤영필,김성은,강은영,김학준,박경순,송해룡 한국조직공학과 재생의학회 2013 조직공학과 재생의학 Vol.10 No.3

The aim of orthopedic and dental tissue engineering is to generate synthetic bone-graft tissue substitutes. It is generally comprised through the combination of viable cells, a scaffolding material, and sometimes the inclusion of bone morphogenic proteins. The object of this study is to develop novel bone-grafting scaffolds that enhance osteoblast activity. We were fabricated the chitosan scaffolds with channel-shaped and spherically shaped pore morphologies. Also, Bone morphogenic protein-2 (BMP-2) was sequentially immobilized to the heparinized-chitosan (Hep-chitosan)scaffolds. Osteoblast activities of all chitosan scaffolds were investigated by a cell proliferation assay, alkaline phosphatase (ALP) activity, calcium deposition, and the expression of osteogenic markers. The results showed that BMP-2-immobilizing heparinized-chitosan (BMP-2/Hep-chitosan) scaffolds significantly enhanced ALP activity and calcium deposition of the osteoblast cells when compared with chitosan scaffolds only. Also, mRNA expressions of osteocalcin and osteopontin of osteoblast cells cultured on BMP-2 (100 ng)/Hep-chitosan scaffolds were increased versus chitosan scaffolds only. Taken together, BMP-2 (100 ng)/Hep-chitosan scaffolds could achieve the functions of excellent osteoblast promotion. Therefore, osteoinductive protein-functionalizing scaffold substrates such as BMP-2/Hepchitosan scaffolds are a promising material for the enhanced osteoblast activity in orthopedic and dental fields

In <i>vitro</i> biocompatibility of vapour phase polymerised conductive scaffolds for cell lines

Choi, Jong Seob,Park, Jin Seul,Kim, Boram,Lee, Byong-Taek,Yim, Jin-Heong Butterworth Scientific Ltd. etc. 2017 Polymer Vol. No.

<P><B>Abstract</B></P> <P>Conductive polymers have been intensively studied for their potential applications in cell therapy, neural regeneration, and drug delivery. They can also be used as scaffolds for tissue engineering. Ideal scaffolds are porous, interconnected structures that allow cell entry and can thus mimic in <I>vivo</I> three-dimensional (3D) tissue regeneration. In the present study, poly(3,4-ethylenedioxythiophene)-silica and polypyrrole-silica composites were fabricated by a two-step procedure for use as 3D conductive porous scaffolds. A hybrid conductive composite layer was first formed by vapour phase polymerisation on a 3D microparticle assembly. Microparticles were then selectively removed, yielding a highly porous skeletal structure. The in <I>vitro</I> biocompatibility of the scaffolds was investigated by culturing with HepG2 and MC3T3-E1 cells, and evaluating cell viability with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and examining cell morphology by scanning electron and confocal microscopy. We found that the two scaffolds effectively promoted cell proliferation, indicating that conductive polymer-based scaffolds can be useful for investigating the behaviour of muscle and nerve cells under electrical stimulation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PEDOT-SiO<SUB>2</SUB> and PPy-SiO<SUB>2</SUB> based 3D conductive porous scaffolds were prepared by VPP. </LI> <LI> In <I>vitro</I> biocompatibility of the scaffolds was confirmed by culturing with two kinds of cells. </LI> <LI> The scaffolds can be useful for studying the behaviour of cells under electrical stimulation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>In this paper, we investigated the biocompatible study of 3D conductive scaffolds mechanically and electrically enhanced by simultaneous co-vaporized VPP.</P> <P>[DISPLAY OMISSION]</P>

브라켓의 변위가 비계 구조 안전성에 미치는 영향 분석

김동현 ( Dong Hyun Kim ),이형도 ( Hyung Do Lee ),원정훈 ( Jeong-hun Won ),정성훈 ( Sung Hoon Jung ) 한국안전학회 2017 한국안전학회지 Vol.32 No.3

This study examined the structural behavior of bracket scaffolds reflecting the influence of bracket`s deflection. Even though the supporting condition of bracket scaffolds is different to that of general earth-supported scaffolds, there is no clear standards about the installation of bracket scaffolds. To compare the structural behaviors of the earth-supported scaffolds without settlements in columns and those of bracket scaffolds installed on the bracket structure, the finite element analysis was performed. The results show that the differential settlement between the scaffold columns installed on the bracket was occurred due to the deflection of the bracket. The differential settlement gave birth to remarkable secondary stress to the scaffold columns. It is resonable to locate all scaffold columns on the brackets, and if unavoidable situation is faced at a site, the horizontal members should not placed alone without columns on the brackets. Moreover, the structural analysis should be performed to ensure structural safety of bracket scaffolds before installation. In addition, the location of wall connection to the structures is recommended to the scaffolds columns installed on the brackets.

In-vitro Studies on Copper Nanoparticles and Nano-hydroxyapatite Infused Biopolymeric Composite Scaffolds for Bone Bioengineering Applications

Shikha Kumari,Abha Mishra,Divakar Singh,Chenzhong Li,Pradeep Srivastava 한국생물공학회 2023 Biotechnology and Bioprocess Engineering Vol.28 No.1

This research study deals with the development of copper nanoparticles (CN) and nano-hydroxyapatite (nHAP) infused chitosan (C) and gelatin (G) based nanocomposite scaffolds for bone tissue engineering applications. Human-origin osteoblast cells (MG-63) were seeded over the scaffolds to investigate the novel biomimetic extracellular matrix system. The scanning electron microscopy (SEM) showed an average pore size between 100-146 μm for all the C-G-nHAP-CN based scaffolds. The in-vitro degradation study showed 74-83% degradation for CN-based scaffolds. For 0.03% CN based scaffold degradation rate (84%) was very close to the control scaffold. Swelling ratio was highest for the chitosan scaffold and it was in the range between 5.25-5.93 mg/mL for other scaffolds. Compressive moduli were highest for 0.03% CN scaffold (3.32 MPa) which was relatively very high in comparison to C-G-nHAP scaffold with 2.4 MPa strength in a wet state. Stress-strain graphs also show the maximum displacement by 0.03% CN scaffold. The functional and structural analysis for the scaffolds showed the presence of nHAP in the scaffold and CN peaks within the composite structure. Differential scanning colorimetry testing showed reduced crystallinity in CN-based scaffolds with a melting temperature of 320ºC. Their 2D cell behaviour in the Electrical Cell Impedance System (ECIS) study showed maximum cell spreading and growth in 0.02% CN-based scaffold. The cell-seeded composite was tested for 3-(4,5-dimethylthiazolyl-2)-2,5- diphenyltetrazolium bromide (MTT), 4,6-diamidino-2- phenylindole (DAPI), and acridine orange and propidium iodide (AOPI) assay for testing its cytocompatibility for MG-63 cell line. Cell proliferation and cell spreading was observed by SEM in all the CN-based scaffolds. Alkaline phosphatase (ALP) activity was highest in 0.03% CN scaffold with 2.0 optical density (OD) value. Alizarin Red Stain (ARS) staining was performed to support this study. It can be statistically depicted that nHAP and 0.03% CNbased scaffold could be potential biomaterial for minor to severe bone-related tissue regeneration applications.

Chondrogenesis using mesenchymal stem cells and PCL scaffolds

Kim, Hye-Joung,Lee, Jin-Ho,Im, Gun-Il Wiley Subscription Services, Inc., A Wiley Company 2010 Journal of biomedical materials research. Part A Vol.a92 No.2

<P>We tested the in vitro feasibility of porous PCL (poly(ϵ-caprolactone)) as a scaffold for cartilage tissue engineering from mesenchymal stem cells (MSCs) and determined the effects of various surface treatments. Three porous PCL scaffold modifications were examined: (1) PCL/Pluronic F127, (2) PCL/collagen, and (3) PCL/Pluronic F127/collagen, in addition to (4) PCL-only. MSCs (5 × 10<SUP>5</SUP>) were seeded in PCL scaffolds of pore size 100–150 μm, and after 3 weeks of in vitro culture, MSC-scaffolds were investigated for gross appearance, DNA amount, glycosaminoglycan (GAG) content, chondrogenic gene expression, and histology. Grossly, the cell-scaffold complexes became harder, and were more easily manipulated with a forceps after 3 weeks of culture. The three surface-treated scaffolds had higher DNA contents than did the PCL-only scaffold, and the GAG contents in PCL/collagen and PCL/F127/collagen scaffolds were higher than those seen in the PCL-only scaffold. Real-time PCR showed that Sox-9 and COL2A1 mRNA levels were remarkably elevated in PCL/collagen and PCL/F127/collagen scaffolds versus the PCL-only scaffold. On the other hand, Col1A1 and Col10A1 mRNA levels were lower in the three modified PCL scaffolds than in the PCL-only scaffold. Histological findings generally concurred with GAG and RT-PCR findings, and demonstrated the affinity of PCL-based scaffolds for MSCs and the potentials of these scaffold to induce chondrogenic differentiation. Cells showed more differentiated appearance and more abundant extracellular matrix formation in PCL/collagen and PCL/collagen/F127 scaffolds. Our findings suggest that PCL-based porous scaffolds may be useful carriers for MSC transplantation in the cartilage tissue engineering field, and that collagen-based surface modifications further enhance the chondrogenic differentiation of MSCs. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res, 2010</P>

Insights into the Therapeutic Potential of Heparinized Collagen Scaffolds Loading Human Umbilical Cord Mesenchymal Stem Cells and Nerve Growth Factor for the Repair of Recurrent Laryngeal Nerve Injury

Yongqin Pan,Genlong Jiao,Jingge Yang,Rui Guo,Jinyi Li,Cunchuan Wang 한국조직공학과 재생의학회 2017 조직공학과 재생의학 Vol.14 No.3

Recurrent laryngeal nerve (RLN) injury can result in unilateral or bilateral vocal cords paralysis, thereby causing a series of complications, such as hoarseness and dyspnea. However, the repair of RLN remains a great challenge in current medicine. This study aimed to develop human umbilical mesenchymal stem cells (HuMSCs) and nerve growth factor (NGF)-loaded heparinized collagen scaffolds (HuMSCs/NGF HC-scaffolds) and evaluate their potential in the repair of RLN injury. HuMSCs/NGF HC-scaffolds were prepared through incorporating HuMSCs and NGF into heparinized collagen scaffolds that were prefabricated by freeze-drying in a template. The resulting scaffolds were characterized by FTIR, SEM, porosity, degradation in vitro, NGF release in vitro and bioactivity. A rabbit RLN injury model was constructed to appraise the performance of HuMSCs/NGF HC-scaffolds for nerve injury repair. Electrophysiology, histomorphology and diagnostic proteins expression for treated nerves were checked after application of various scaffolds. The results showed that the composite scaffolds with HuMSCs and NGF were rather helpful for the repair of broken RLN. The RLN treated with HuMSCs/NGF HC-scaffolds for 8 weeks produced a relatively normal electromyogram, and the levels of calciumbinding protein S100, neurofilament and AchE pertinent to nerve were found to be close to the normal ones but higher than those resulted from other scaffolds. Taken together, HuMSCs/NGF HC-scaffolds exhibited a high score on the nerve injury repair and may be valuable for the remedy of RLN injury.

Cellular and Soft Tissue Compatibility to High Interconnectivity between Pores of Chitosan Scaffold

Park, Sang-Jun,Kim, Min-Sup,Yu, Seong-Mi,Gu, Bon-Kang,Kim, Jong-Il,Kim, Chun-Ho 한국고분자학회 2012 Macromolecular Research Vol.20 No.4

In the field of tissue engineering and regenerative medicine, porosity, pore size, and pore interconnectivity of three-dimensional scaffolds affect cellular attachment, proliferation and, migration, and degree of tissue infiltration. In this study, porous chitosan scaffolds with macropores interconnected by micropores were prepared using a thermally induced phase-separation process. Water adsorption properties of scaffolds were investigated by soaking in phosphate-buffered saline (PBS) at room temperature. The chitosan scaffold with macropores interconnected by micropores (CS-10B) adsorbed PBS more rapidly than a chitosan scaffold containing only macropores (CS). An investigation of cell attachment and distribution showed that human dermal fibroblasts (HDFs) culture on chitosan scaffolds $in$ $vitro$ were present on both the surface and cross-sections of the CS-10B scaffold, but only on the surface of the CS scaffold. Studies of tissue responses to the prepared scaffolds, evaluated by subcutaneous implantation in rats, showed that the organization of tissues in the CS-10B scaffold was superior to that in the CS scaffold, and the CS-10B implant degraded faster than the CS implant $in$ $vivo$. The high interconnectivity of porous scaffolds with macropores interconnected by micropores enhanced biocompatibility and biodegradability, suggesting the excellent potential applications of such chitosan scaffolds in the field of tissue engineering and regenerative medicine.