A review on stereolithography and its applications in biomedical engineering

Stereolithography is a solid freeform technique (SFF) that was introduced in the late 1980s. Although many other techniques have been developed since then, stereolithography remains one of the most powerful and versatile of all SFF techniques. It has the highest fabrication accuracy and an increasing number of materials that can be processed is becoming available. In this paper we discuss the characteristic features of the stereolithography technique and compare it to other SFF techniques. The biomedical applications of stereolithography are reviewed, as well as the biodegradable resin materials that have been developed for use with stereolithography. Finally, an overview of the application of stereolithography in preparing porous structures for tissue engineering is given.

Biomedical engineering for healthy ageing. Predictive tools for falls

Falls are common and burdensome accidents among the elderly. About one third of the population aged 65 years or more experience at least one fall each year. Fall risk assessment is believed to be beneficial for fall prevention. This thesis is about prognostic tools for falls for community-dwelling older adults. We provide an overview of the state of the art. We then take different approaches: we propose a theoretical probabilistic model to investigate some properties of prognostic tools for falls; we present a tool whose parameters were derived from data of the literature; we train and test a data-driven prognostic tool. Finally, we present some preliminary results on prediction of falls through features extracted from wearable inertial sensors. Heterogeneity in validation results are expected from theoretical considerations and are observed from empirical data. Differences in studies design hinder comparability and collaborative research. According to the multifactorial etiology of falls, assessment on multiple risk factors is needed in order to achieve good predictive accuracy.

Rapid prototyping for biomedical engineering: current capabilities and Challenges

A new set of manufacturing technologies has emerged in the past decades to address market requirements in a customized way and to provide support for research tasks that require prototypes. These new techniques and technologies are usually referred to as rapid prototyping and manufacturing technologies, and they allow prototypes to be produced in a wide range of materials with remarkable precision in a couple of hours. Although they have been rapidly incorporated into product development methodologies, they are still under development, and their applications in bioengineering are continuously evolving. Rapid prototyping and manufacturing technologies can be of assistance in every stage of the development process of novel biodevices, to address various problems that can arise in the devices' interactions with biological systems and the fact that the design decisions must be tested carefully. This review focuses on the main fields of application for rapid prototyping in biomedical engineering and health sciences, as well as on the most remarkable challenges and research trends.

QUT Medical Engineering Research Facility (MERF) annual report 2009

DIRECTOR’S OVERVIEW by Professor Mark Pearcy This report for 2009 is the first full year report for MERF. The development of our activities in 2009 has been remarkable and is testament to the commitment of the staff to the vision of MERF as a premier training and research facility. From the beginnings in 2003, when a need was identified for the provision of specialist research and training facilities to enable close collaboration between researchers and clinicians, to the realisation of the vision in 2009 has been an amazing journey. However, we have learnt that there is much more that can be achieved and the emphasis will be on working with the university, government and external partners to realise the full potential of MERF by further development of the Facility. In 2009 we conducted 28 workshops in the Anatomical and Surgical Skills Laboratory providing training for surgeons in the latest techniques. This was an excellent achievement for the first full year as our reputation for delivering first class facilities and support grows. The highlight, perhaps, was a course run via our video link by a surgeon in the USA directing the participants in MERF. In addition, we have continued to run a small number of workshops in the operating theatre and this promises to be an avenue that will be of growing interest. Final approval was granted for the QUT Body Bequest Program late in 2009 following the granting of an Anatomical Accepting Licence. This will enable us to expand our capabilities by provide better material for the workshops. The QUT Body Bequest Program will be launched early in 2010. The Biological Research Facility (BRF) conducted over 270 procedures in 2009. This is a wonderful achievement considering less then 40 were performed in 2008. The staff of the BRF worked very hard to improve the state of the old animal house and this resulted in approval for expanded use by the ethics committees of both QUT and the University of Queensland. An external agency conducted an Occupational Health and Safety Audit of MERF in 2009. While there were a number of small issues that require attention, the auditor congratulated the staff of MERF on achieving a good result, particularly for such an early stage in the development of MERF. The journey from commissioning of MERF in 2008 to the full implementation of its activities in 2009 has demonstrated the potential of this facility and 2010 will be an exciting year as its activities are recognised and further expanded building development is pursued.

Force-controlled automatic microassembly of tissue engineering scaffolds

This paper presents an automated system for 3D assembly of tissue engineering (TE) scaffolds made from biocompatible microscopic building blocks with relatively large fabrication error. It focuses on the pin-into-hole force control developed for this demanding microassembly task. A beam-like gripper with integrated force sensing at a 3 mN resolution with a 500 mN measuring range is designed, and is used to implement an admittance force-controlled insertion using commercial precision stages. Visual-based alignment followed by an insertion is complemented by a haptic exploration strategy using force and position information. The system demonstrates fully automated construction of TE scaffolds with 50 microparts whose dimension error is larger than 5%.

Fabrication using a rapid prototyping system and in vitro characterization of PEG-PCL-PLA scaffolds for tissue engineering

n the field of tissue engineering new polymers are needed to fabricate scaffolds with specific properties depending on the targeted tissue. This work aimed at designing and developing a 3D scaffold with variable mechanical strength, fully interconnected porous network, controllable hydrophilicity and degradability. For this, a desktop-robot-based melt-extrusion rapid prototyping technique was applied to a novel tri-block co-polymer, namely poly(ethylene glycol)-block-poly(epsi-caprolactone)-block-poly(DL-lactide), PEG-PCL-P(DL)LA. This co-polymer was melted by electrical heating and directly extruded out using computer-controlled rapid prototyping by means of compressed purified air to build porous scaffolds. Various lay-down patterns (0/30/60/90/120/150°, 0/45/90/135°, 0/60/120° and 0/90°) were produced by using appropriate positioning of the robotic control system. Scanning electron microscopy and micro-computed tomography were used to show that 3D scaffold architectures were honeycomb-like with completely interconnected and controlled channel characteristics. Compression tests were performed and the data obtained agreed well with the typical behavior of a porous material undergoing deformation. Preliminary cell response to the as-fabricated scaffolds has been studied with primary human fibroblasts. The results demonstrated the suitability of the process and the cell biocompatibility of the polymer, two important properties among the many required for effective clinical use and efficient tissue-engineering scaffolding.