Multifunctional Devices for Rapid Point-of-Care Diagnostics

Molecularly imprinted polymers (MIPs) composed of cavities corresponding to the shape and functionalities of the target analyte have shown promising applications in (bio)sensing. MIPs are defined as chemically synthesised materials, which can be exploited as potential biomimetic antibodies to detect specific biomarkers with a high accuracy.1 The advantages of these synthetic tailor-made materials include physical and chemical stability, reusability, easy synthesis, and cost-efficiency.2 However, imprinting of large biomolecules, for example, proteins, still remains a challenge due to their complex structure, large dimensions, and limited stability and solubility.3 To overcome these issues, the technique of epitope imprinting has been employed. This approach creates selective recognition cavities for biomacromolecules using only a small specific part of the protein (epitope) thus, avoiding the challenges associated with templating the entire protein.4

Currently, conducting polymers (CPs) have become an attractive material for the development of (bio)sensors due to their excellent ability to immobilize biomolecules and their rapid electron transfer.5 CPs are described as polymers constructed of a conjugated n system on their backbone, which enables the movement of electrons within the polymeric chain and is responsible for their unique electrical properties.6 The incorporation of CPs into MIPs results in molecularly imprinted conducting polymers (MICPs), which can be directly deposited on to electrode surfaces.7 MICPs can be exploited to establish a relationship between the concentration of a target analyte whilst simultaneously measuring the electrical property. However, there appear to be issues associated with CPs including poor solubility, stability and processability.8 This has led to the discovery of hybrid conducting polymers (HPCs), which are described as polymers possessing combined properties of both inorganic/organic nanoparticles and CPs. The use of HCPs increases conductivity, and this is attributed to their electron delocalization. Ultimately, the use of CPs alone is not adequate to fulfil the required characteristics for a highly sensitive and selective (bio)sensor. However, combining the construction of MIPs with the incorporation of HCPs (MIHCPs) can lead to the development of an increasingly selective and sensitive diagnostic device.

The aims of this project will be to design a MIHCP for the identification and determination of biomarkers for specific infections in order to prevent the unnecessary distribution of antibiotics and decrease the time taken for treatment. The synthesis of this MIHCP will employ epitope imprinting and electrochemical analysis, with the intention to develop a point-of-care device, which will be of universal distribution. This project will involve a variety of characterisations including UV spectroscopy, field emission scanning electron microscopy, electrochemical impedance spectroscopy , thermogravimetric analysis, differential scanning calorimetry and dynamic mechanical analysis.

Bi-weekly meetings have been arranged between Dr Hannah Leese and I to discuss progress and any concerns that may arise. Monthly meetings have been arranged between Hannah, my secondary supervisors (Dr Pedro Estrella and Dr Despina Moschou) and I. The date of my first attempt of confirmation will take place in 1 year and a specific date will be arranged closer to the time.

1. R. Xing, et al., (2019) Chem. Sci. 10, 1831-1835.
2. X. Li, et al., (2015) Sensor. Actuator. B. Chem. 208, 559-568.
3. M. Dinc et al., (2018) Chemistry Select 3, 4277-4282.
4. M. Dinc, et al., (2019) Trends Anal. Chem. 114, 202-217.
5. S. Nambiar, J. Yeow, (2011) Biosens. Bioelectron. 26, 1825-1832.
6. A. Rahman, et al., (2008) Electro. Sens. Based Org. Conjugated Poly. 8, 118-141.
7. A. Gonzalez-Vogel et al., (2019) Sens. & Actuat.: B Chemical 295, 186-193.
8. C. Sanchez, et al., (2005) J. Mater. Chem. 15, 3559-3592.