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Article
Publication date: 18 April 2017

Saahil V. Mehendale, Liliana F. Mellor, Michael A. Taylor, Elizabeth G. Loboa and Rohan A. Shirwaiker

This study aims to investigate the effect of three-dimensional (3D)- bioplotted polycaprolactone (PCL) scaffold geometry on the biological and mechanical characteristics of human…

Abstract

Purpose

This study aims to investigate the effect of three-dimensional (3D)- bioplotted polycaprolactone (PCL) scaffold geometry on the biological and mechanical characteristics of human adipose-derived stem cell (hASC) seeded constructs.

Design/methodology/approach

Four 3D-bioplotted scaffold disc designs (Ø14.5 × 2 mm) with two levels of strand–pore feature sizes and two strand laydown patterns (0°/90° or 0°/120°/240°) were evaluated for hASC viability, proliferation and construct compressive stiffness after 14 days of in vitro cell culture.

Findings

Scaffolds with the highest porosity (smaller strand–pore size in 0°/120°/240°) yielded the highest hASC proliferation and viability. Further testing of this design in a 6-mm thick configuration showed that cells were able to penetrate and proliferate throughout the scaffold thickness. The design with the lowest porosity (larger strand–pore size in 0°/90°) had the highest compression modulus after 14 days of culture, but resulted in the lowest hASC viability. The strand laydown pattern by itself did not influence the compression modulus of scaffolds. The 14-day cell culture also did not cause significant changes in compressive properties in any of the four designs.

Originality/value

hASC hold great potential for musculoskeletal tissue engineering applications because of their relative ease of harvest, abundance and differentiation abilities. This study reports on the effects of 3D-bioplotted scaffold geometry on mechanical and biological characteristics of hASC-seeded PCL constructs. The results provide the basis for future studies which will use this optimal scaffold design to develop constructs for hASC-based osteochondral tissue engineering applications.

Details

Rapid Prototyping Journal, vol. 23 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 October 2015

Yan Li, Dichen Li, Bingheng Lu, Dajing Gao and Jack Zhou

The purpose of this paper is to review the current status of additive manufacturing (AM) used for tissue engineering (TE) scaffold. AM processes are identified as an effective…

1097

Abstract

Purpose

The purpose of this paper is to review the current status of additive manufacturing (AM) used for tissue engineering (TE) scaffold. AM processes are identified as an effective method for fabricating geometrically complex objects directly from computer models or three-dimensional digital representations. The use of AM technologies in the field of TE has grown rapidly in the past 10 years.

Design/methodology/approach

The processes, materials, precision, applications of different AM technologies and their modified versions used for TE scaffold are presented. Additionally, future directions of AM used for TE scaffold are also discussed.

Findings

There are two principal routes for the fabrication of scaffolds by AM: direct and indirect routes. According to the working principle, the AM technologies used for TE scaffold can be generally classified into: laser-based; nozzle-based; and hybrid. Although a number of materials and fabrication techniques have been developed, each AM technique is a process based on the unique property of the raw materials applied. The fabrication of TE scaffolds faces a variety of challenges, such as expanding the range of materials, improving precision and adapting to complex scaffold structures.

Originality/value

This review presents the latest research regarding AM used for TE scaffold. The information available in this paper helps researchers, scholars and graduate students to get a quick overview on the recent research of AM used for TE scaffold and identify new research directions for AM in TE.

Details

Rapid Prototyping Journal, vol. 21 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 26 July 2013

Wei Huang, Xianglin Zhang, Quan Wu and Bin Wu

The purpose of this paper is to introduce a novel and concise technique of fabricating HA/β‐TCP composite ceramic scaffolds for bone tissue engineering via extrusion deposition…

Abstract

Purpose

The purpose of this paper is to introduce a novel and concise technique of fabricating HA/β‐TCP composite ceramic scaffolds for bone tissue engineering via extrusion deposition method.

Design/methodology/approach

A new rapid prototyping (RP) machine called motor assisted micro‐syringe (MAM) system is used in the authors' research. It is implemented to control the morphology, pore size and porosity of scaffolds precisely and to optimize their mechanical properties in this study.

Findings

In the fabrication process, HA/β‐TCP ceramic composite slurry with prominent uniformity, stability and liquidity is prepared by deliberating the influential factors such as its ingredient, pH and viscosity. After optimizing the system parameters, scaffolds with homogeneous and interconnected pores in sizes ranging from 50 to 580 μm were obtained, and the whole process had excellent stability and repeatability. The average compressive strength of scaffolds with a porosity of around 50% reaches 50.33 MPa after sintered in microwave furnace at 1,200°C for 30 min.

Research limitations/implications

Degradation rates and biological properties concluding experiments in vitro and vivo should be further investigated.

Practical implications

The paper describes a brief method with excellent stability and repeatability which is practical for manufacturing composite ceramic scaffolds with desirable structures and strength.

Originality/value

The mentioned method can be used in tissue engineering, not only proper for ceramics scaffolds but many medical application fields such as implants.

Details

Rapid Prototyping Journal, vol. 19 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 9 March 2010

Florencia Edith Wiria, Novella Sudarmadji, Kah Fai Leong, Chee Kai Chua, E. Wei Chng and Chian Chai Chan

In recent years, selective laser sintering (SLS) has been used in the biomedical field, including building small‐scaled biomedical devices such as tissue engineering scaffolds and…

1233

Abstract

Purpose

In recent years, selective laser sintering (SLS) has been used in the biomedical field, including building small‐scaled biomedical devices such as tissue engineering scaffolds and drug delivery devices. A compact adaptation system for the SLS is needed to obtain a more effective and efficient way of sintering small‐scale prototypes so as to reduce powder wastage. Limitations of available smaller‐scale adaptation devices include the need of additional electrical supplies for the device. The purpose of this paper is to report the development of such a system to be mounted at the SLS part bed without any additional energy supply.

Design/methodology/approach

The compact adaptation device works on the concept of transferring the motion of the SLS part bed onto the part bed of the compact adaptation device. The device is an integrated attachment that is fixed onto the building platform of the SLS. The gear system of the device lifts the powder supply bed at both sides of the device simultaneously when the part bed at the center of the device is lowered. To further increase powder saving, an improved powder delivery system named alternative supply mechanism (ASM) is mounted on top of the roller to be coupled together with the compact adaptation device.

Findings

Powder saving up to 6.5 times compared to using full build version of the Sinterstation 2500 has been achieved by using the compact adaptation device. Furthermore, powder wastage has been reduced by 84 percent when using the ASM compared to the compact adaptation device alone.

Originality/value

The paper demonstrates the development and viability of adaptation devices for SLS to significantly reduce powder consumption by using solely mechanical means to build small parts without using external power supply.

Details

Rapid Prototyping Journal, vol. 16 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 6 August 2019

Jingrong Li, Zhijia Xu, Qinghui Wang, Guanghua Hu and Yingjun Wang

The three-dimensional porous scaffold is an important concept in tissue engineering and helps to restore or regenerate a damaged tissue. Additive manufacturing (AM) technology…

Abstract

Purpose

The three-dimensional porous scaffold is an important concept in tissue engineering and helps to restore or regenerate a damaged tissue. Additive manufacturing (AM) technology makes the production of custom-designed scaffolds possible. However, modeling scaffolds with intricate architecture and customized pore size and spatial distribution presents a challenge. This paper aims to achieve coupling control of pore size and spatial distribution in bone scaffolds for AM.

Design/methodology/approach

First, the proposed method assumes that pore size and spatial distribution have already been transformed from the requirements of scaffolds as inputs. Second, the structural characteristics of scaffolds are explicitly correlated with an all-hexahedron meshing method for scaffold design so that the average pore size could be controlled. Third, the highly coupled internal mesh vertices are adjusted based on a random strategy so that the pore size and spatial distribution conform to their respective desired values. Fourth, after the adjustment, the unit pore cell based on a triply periodic minimal surface was mapped into the hexahedrons through a shape function, thereby ensuring the interconnectivity of the porous scaffold.

Findings

The case studies of three bone scaffolds demonstrate that the proposed approach is feasible and effective to simultaneously control pore size and spatial distribution in porous scaffolds.

Practical implications

The proposed method may make it more flexible to design scaffolds with controllable internal pore architecture for AM.

Originality/value

In the control approach, the highly coupled mesh vertices are adjusted through a random strategy, which can determine the moving direction and range of a vertex dynamically and biasedly, thus ensuring the feasibility and efficiency of the proposed method.

Article
Publication date: 9 April 2018

Hoejin Kim, Yirong Lin and Tzu-Liang Bill Tseng

The usage of additive manufacturing (AM) technology in industries has reached up to 50 per cent as prototype or end-product. However, for AM products to be directly used as final…

4608

Abstract

Purpose

The usage of additive manufacturing (AM) technology in industries has reached up to 50 per cent as prototype or end-product. However, for AM products to be directly used as final products, AM product should be produced through advanced quality control process, which has a capability to be able to prove and reach their desire repeatability, reproducibility, reliability and preciseness. Therefore, there is a need to review quality-related research in terms of AM technology and guide AM industry in the future direction of AM development.

Design/methodology/approach

This paper overviews research progress regarding the QC in AM technology. The focus of the study is on manufacturing quality issues and needs that are to be developed and optimized, and further suggests ideas and directions toward the quality improvement for future AM technology. This paper is organized as follows. Section 2 starts by conducting a comprehensive review of the literature studies on progress of quality control, issues and challenges regarding quality improvement in seven different AM techniques. Next, Section 3 provides classification of the research findings, and lastly, Section 4 discusses the challenges and future trends.

Findings

This paper presents a review on quality control in seven different techniques in AM technology and provides detailed discussions in each quality process stage. Most of the AM techniques have a trend using in-situ sensors and cameras to acquire process data for real-time monitoring and quality analysis. Procedures such as extrusion-based processes (EBP) have further advanced in data analytics and predictive algorithms-based research regarding mechanical properties and optimal printing parameters. Moreover, compared to others, the material jetting progresses technique has advanced in a system integrated with closed-feedback loop, machine vision and image processing to minimize quality issues during printing process.

Research limitations/implications

This paper is limited to reviewing of only seven techniques of AM technology, which includes photopolymer vat processes, material jetting processes, binder jetting processes, extrusion-based processes, powder bed fusion processes, directed energy deposition processes and sheet lamination processes. This paper would impact on the improvement of quality control in AM industries such as industrial, automotive, medical, aerospace and military production.

Originality/value

Additive manufacturing technology, in terms of quality control has yet to be reviewed.

Abstract

Purpose

Additive manufacturing (AM) or solid freeform fabrication (SFF) technique is extensively used to produce intrinsic 3D structures with high accuracy. Its significant contributions in the field of tissue engineering (TE) have significantly increased in the recent years. TE is used to regenerate or repair impaired tissues which are caused by trauma, disease and injury in human body. There are a number of novel materials such as polymers, ceramics and composites, which possess immense potential for production of scaffolds. However, the major challenge is in developing those bioactive and patient-specific scaffolds, which have a required controlled design like pore architecture with good interconnectivity, optimized porosity and microstructure. Such design not only supports cell proliferation but also promotes good adhesion and differentiation. However, the traditional techniques fail to fulfill all the required specific properties in tissue scaffold. The purpose of this study is to report the review on AM techniques for the fabrication of TE scaffolds.

Design/methodology/approach

The present review paper provides a detailed analysis of the widely used AM techniques to construct tissue scaffolds using stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling (FDM), binder jetting (BJ) and advanced or hybrid additive manufacturing methods.

Findings

Subsequently, this study also focuses on understanding the concepts of TE scaffolds and their characteristics, working principle of scaffolds fabrication process. Besides this, mechanical properties, characteristics of microstructure, in vitro and in vivo analysis of the fabricated scaffolds have also been discussed in detail.

Originality/value

The review paper highlights the way forward in the area of additive manufacturing applications in TE field by following a systematic review methodology.

Details

Rapid Prototyping Journal, vol. 27 no. 6
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 1 April 2005

Li Geng, Wei Feng, Dietmar W. Hutmacher, Yoke San Wong, Han Tong Loh and Jerry Y.H. Fuh

This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds.

3671

Abstract

Purpose

This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds.

Design

A desktop rapid prototyping robot dispensing (RPBOD) system has been developed to fabricate scaffolds for tissue engineering (TE) applications. The system is a computer‐controlled four‐axis machine with a multiple‐dispenser head. Neutralization of the acetic acid by the sodium hydroxide results in a precipitate to form a gel‐like chitosan strand. The scaffold properties were characterized by scanning electron microscopy, porosity calculation and compression test. An example of fabrication of a freeform hydrogel scaffold is demonstrated. The required geometric data for the freeform scaffold were obtained from CT‐scan images and the dispensing path control data were converted form its volume model. The applications of the scaffolds are discussed based on its potential for TE.

Findings

It is shown that the RPBOD system can be interfaced with imaging techniques and computational modeling to produce scaffolds which can be customized in overall size and shape allowing tissue‐engineered grafts to be tailored to specific applications or even for individual patients.

Research limitations/implications

Important challenges for further research are the incorporation of growth factors, as well as cell seeding into the 3D dispensing plotting materials. Improvements regarding the mechanical properties of the scaffolds are also necessary.

Originality/value

One of the important aspects of TE is the design scaffolds. For customized TE, it is essential to be able to fabricate 3D scaffolds of various geometric shapes, in order to repair tissue defects. RP or solid free‐form fabrication techniques hold great promise for designing 3D customized scaffolds; yet traditional cell‐seeding techniques may not provide enough cell mass for larger constructs. This paper presents a novel attempt to fabricate 3D scaffolds, using hydrogels which in the future can be combined with cells.

Details

Rapid Prototyping Journal, vol. 11 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 23 October 2021

Fangfang Sun, Tianze Wang and Yong Yang

Rapid prototyping (RP) technology is widely used in many fields in recent years. Bone tissue engineering (TE) is an interdisciplinary field involving life sciences, engineering…

Abstract

Purpose

Rapid prototyping (RP) technology is widely used in many fields in recent years. Bone tissue engineering (TE) is an interdisciplinary field involving life sciences, engineering and materials science. Hydroxyapatite (HAp) are similar to natural bone and it has been extensively studied due to its excellent biocompatibility and osteoconductivity. This paper aims to review nanoscaled HAp-based scaffolds with high porosity fabricated by various RP methods for bone regeneration.

Design/methodology/approach

The review focused on the fabrication methods of HAp composite scaffolds through RP techniques. The paper summarized the evaluation of these scaffolds on the basis of their biocompatibility and biodegradability through in vitro and in vivo tests. Finally, a summary and perspectives on this active area of research are provided.

Findings

HAp composite scaffold fabricated by RP methods has been widely used in bone TE and it has been deeply studied by researchers during the past two decades. However, its brittleness and difficulty in processing have largely limited its wide application in TE. Therefore, the formability of HAp combined with biocompatible organic materials and fabrication techniques could be effectively enhanced, and it can be used in bone TE applications finally.

Originality/value

This review paper presented a comprehensive study of the various types of HAp composite scaffold fabricated by RP technologies and introduced their potential application in bone TE, as well as future roadmap and perspective.

Details

Rapid Prototyping Journal, vol. 28 no. 3
Type: Research Article
ISSN: 1355-2546

Keywords

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