Simple and low-cost manufacturing of customisable drug delivery devices and flexible sensors for biomedical applications

Tan, Deck Khong (2021) Simple and low-cost manufacturing of customisable drug delivery devices and flexible sensors for biomedical applications. Doctoral thesis (PhD), University of Sussex.

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Abstract

In recent years, 3D printing technologies have been adopted into the medical and pharmaceutical industry for the fabrication of personalised medicines, oral dosage forms, medical implants, medical devices, tissue engineering applications, and many more. However, the use of 3D printing, in particular the low-cost Fused Deposition Modelling (FDM) 3D printing technique, has been limited due to the limited number of biocompatible materials suitable for pharmaceutical and biomedical applications. In this study, the FDM 3D printing technique was being explored for the fabrication of pharmaceutical products as it is the most widely available and easily accessible 3D printing technology.

In order to improve the usability of FDM 3D printing for pharmaceutical and biomedical applications, the studies to fabricate several different biocompatible filaments composition that can be used for drug loading were carried out. Firstly, filaments made of several pharmaceutical grade polymers were being developed using hot-melt extrusion (HME). Three types of biocompatible polymeric filaments have been developed. They are (Polylactic Acid) PLA-based, (Hydroxypropyl Cellulose) HPC-based and (Polycaprolactone) PCL-based. These filaments were added with a plasticiser, polyethylene glycol (PEG), to improve their processability and physicochemical properties of the produced filaments so that they can used in an FDM 3D printer. The HPC-based filaments were loaded with a model drug, theophylline, that exhibits poor aqueous solubility, whereas the PCL-based filaments were loaded with a readily soluble model drug, metformin. The studies showed that the filaments were effective in sustaining the release of both drug, and the sustain release properties of the filaments can be adjusted by altering the composition of the polymers.

The studies showed that the HME technology is very compatible with FDM 3D printing as it is able to produce 3D printable filaments by mixing different polymeric materials. The filaments can also be loaded with a desired drug at a required dose to allow the 3D printing of drug delivery systems. This technique allows the fabrication of personalised drug delivery systems in-house. It can be beneficial for clinics and hospitals in remote areas as the lead times can be reduced when in-house fabrication is possible. The ability to fabricate personalised medicines at hand also means that the dose can drug release patterns can be altered for the patients at any point of time when required. Apart from that, this technique can change way medicines are transported and stored, which could potentially help save cost on transportation and inventory. In addition to medicines, the FDM 3D printing technique can also be used to produce other personalised drug delivery systems such as microneedles, braces and implants of various shapes due to the flexibility of the 3D printing process.

The other aspect of this research was on the fabrication of biomedical sensors that can potentially be integrated with the 3D printed drug delivery systems to form a smart drug delivery device. The idea of smart drug delivery device is that it is capable of continuous monitoring the health of a patient and then administer drug to the patient whenever it is required. The development of such smart medical devices has been one of the hottest interests in the biomedical sector. One of the main issues with such technologies is the high cost which has caused the technologies to be not so affordable for many people. Therefore, the studies to fabricate some simple biomedical sensors such as a temperature sensor and a glucose sensor using simple and cost-effective manufacturing technique were being explored. The fabrication techniques used are FDM 3D printing and a thin-film fabrication technique that involves deposition of material using a thermal evaporator. Low-cost manufacturing techniques were being explored in order to help reduce manufacturing cost which could help improve the affordability of such technologies. The fabricated temperature and glucose sensors exhibit great stability in performance and mechanical flexibility. The flexibility allows the sensors to be conformable to curved surfaces such as the skin. Hence, the sensors are suitable to be used as a wearable device or integrated into some other medical devices to form a smart medical device.

Item Type: Thesis (Doctoral)
Schools and Departments: School of Life Sciences > Chemistry
Subjects: R Medicine > R Medicine (General) > R856 Biomedical engineering. Electronics. Instrumentation
T Technology > TP Chemical technology > TP0248.13 Biotechnology
Depositing User: Library Cataloguing
Date Deposited: 05 Aug 2021 08:12
Last Modified: 05 Aug 2021 08:12
URI: http://sro.sussex.ac.uk/id/eprint/100912

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