Development of a Label-Free Electrochemical Immunosensor for the Detection of Prostate Cancer
Authors: Rawlinson Sean , Kanyong Prosper , McLaughlin James , Davis James 
Published: February 2020

Prostate cancer or carcinoma of the prostate is one of the most frequently diagnosed malignancies in the world. Prostate cancer is the second leading cause of cancer death in men worldwide and the fourth most common cancer overall, with more than 1.1 million new cases diagnosed in 2012, and more than 307,000 deaths from the disease1. The prevalence of the condition and mortality will clearly vary from one country to another but tends to be higher in developed countries2. Prostate cancer incidence is strongly linked to age with the lowest incidence rates being in younger men. In the UK between 2009 and 2011, only 1% of cases were diagnosed in men under 50 and an average of 36% of cases was diagnosed in men aged 75 years and over1. In a population with increasing longevity, it is likely that prostate cancer will become even more clinically prevalent in the future. This projected increase is a major concern for the public health sector, especially when there are both problems associated with the detection and the treatment of prostate cancer. Specifically, current practice in prostate cancer and staging leads to inaccurate assessments often resulting in unwanted or even unnecessary treatments that adversely affect the patient’s quality of life with little gain. It will also place a considerable burden on the healthcare provider.
The presentation will detail a new approach to the development of microfluidic paper-based electrochemical devices that will be capable of label-free multiparametric detection. Rather than examining single parameter detection, the strategy adopted here involves the laser machining of cellulose based substrates to create an array of microfluidic channels and detection wells as detailed in Figure 1. Screen printed electrodes functionalised with gold nanoparticles onto which a variety of molecular recognition elements (enzyme or antibody) are immobilised, serve as the principal detection elements. These can be independently addressed thereby providing a system which is capable of screening a panel of biomarkers relevant to the diagnosis of prostate cancer. An innovative approach to the detection methodology is taken where the use of a nitro functionalised biotin – streptavidin conjugate is employed as a redox probe through which to assess the degree of antibody-antigen binding events at the electrode array. The use of Label-free detection over traditional methods such as enzyme-linked immunosorbent assay (ELISA) provides several advantages including speed, simplicity, low cost and sensitivity, and also lays the foundations for the development of a point of care device. The design, development and bioanalytical characterisation of the prototype sensing systems will be presented and the applicability to point of care diagnosis critically assessed.

1.UK, C. R. Prostate cancer mortality statistics.(2014); 2.Ferlay J et al. GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No.11. Lyon, France: International Agency for Research on Cancer; 2013.

Figure 1