University of Twente Student Theses


Conceptual design of a microfluidic-based platform for medical diagnosis

Groot, D.J.A. de (2020) Conceptual design of a microfluidic-based platform for medical diagnosis.

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Abstract:Benchmark Electronics is an electronics manufacturer mainly active in the medical sector. Benchmark’s office in Almelo offers customers R&D, high-tech manufacturing, and design engineering services. Through previous graduation assignments and internal projects, Benchmark has been working on a universal platform for microfluidic-based medical diagnosis. The platform is to be suitable for both research purposes and for use as a POC testing device. As Benchmark’s platform is currently under development, the concept is not very clear yet, and significant parts are yet to be concretised. This thesis aims to concretise the functions of the platform, the system and its components, a preliminary requirements specification, user interactions, and most importantly establish a design language. For this thesis I spent twelve weeks working for Benchmark Electronics in Almelo. The results are to be used for marketing purposes, and for the continued development of the platform. Microfluidics is the technology of manipulating very small amounts of liquid (internal volumes less than 100 μL) on a microfluidic chip. This technology allows for complete chemical processes to be embedded onto one microfluidic chip, in the form of a so-called LOC. LOC analytics has various benefits compared to traditional analytical chemistry, such as faster chemical analysis, parallel experiments, lower risk of contamination, lower reagent consumption, and lower operator skill requirements. This makes LOC technology very suitable to be used in POC diagnosis devices. In order to perform analysis on a microfluidic chip, various chip-to-world connections need to be established to control on chip behaviour (pump liquids, provide pressure or electricity). In contrast with the competition, Benchmark’s platform is capable of automatically making these chip-to-world connections, given that the chip is proprietarily developed in line with the standard. This means that the reagents necessary for the on-chip reaction with the to-be-analysed sample are administered to the chip by the device. From this stem the basic functional requirements of the platform: ▪ It shall be able to accept a test cartridge and connect to the microfluidic chip. ▪ It shall be able to store reagents and administer these reagents to the chip when conducting a test. ▪ For testing, it should be able to conduct analysis via fluorescence spectroscopy. Important next are what use-situations exist for the platform. For this, POC and laboratory-use were recognised as the most important. 1) In a POC setting, the device will be used by a medical professional like a GP or physician to carry out a medical assay for a patient. Instead of sending the sample to a medical laboratory with a long throughput time, the medical professional can carry out the test in-practice, which leads to better healthcare. For the POC use-case, tests are proprietary and predefined. 2) In the laboratory use-case, the platform will be used for the development of new microfluidic chips, complex diagnostics, and drug development. For this use-case, important is the ability to monitor reactions closely and accurately, and to be able to carry out a large variety of (not per-se predefined) tests. On top of this, the laboratory variant shall have a door for the operator to access the internals of the device. Now that the core functions of the device and its functional variants are concretised, the project enters the design-phase. First, a general investigation was done into literature describing points of attention for designing in the medical space. This, and various form studies of existing devices, formed the basis of inspiration for exploratory ideation. Concepts where defined ranging three design directions, which were based on the spatial orientation of the internal mechanism components (see figure). Three design directions based on orientation of components Through various feedback meetings and continuous iterator, a near-final concept was chosen and made into a physical model (see figure on the next page). The model effectively demonstrated the scale of the device, and relevant the affordances such as the screen and cartridge slot. To test some of these affordances and key man-machine-interfaces a semi-functional mock-up was made of the UI and a small user-test was conducted, revealing some small improvements for finalizing the design. Photos of the model and the important user interactions The design was finalized after a thorough design review. The final device (see next page) features a glossy white HDPE body with a black glass panel facing the user. Embedded within the glass are the display, capacitive fingerprint-scanner and ON-button, and the reagent slide. Slightly lower, embedded in the body of the device, is the cover behind which the reagents are stored. Through here, the operator can exchange and refill reagent reservoirs. The side of the device features an interface for modular expansions, such as a module for extra reagent storage. The laboratory variant also includes a door for the operator to access the internals. The device is relatively small, with a footprint of only 23x35 cm and a total hight of 40 cm. It is estimated to weigh under 8 kg and should be very portable with the integrated carrying handle. To aid in portability, the device includes a sophisticated power supply, with surge protector and battery. Furthermore, the chapter on future design directions describes some ideas for peripherals to the device to make it more rugged (e.g. screen protector and foam padding)
Item Type:Essay (Bachelor)
Faculty:ET: Engineering Technology
Subject:42 biology, 44 medicine, 50 technical science in general, 52 mechanical engineering
Programme:Industrial Design BSc (56955)
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