Determination of Total PSA Using Magnetic Beads and a Re‐usable Screen Printed Carbon Electrode Array

Abstract

[a] 1IntroductionProstate cancer accounts for 10 %o fa ll deaths from cancer [1,2] and the prostate specific antigen (PSA) is the best serumm arkerc urrently available for the preoperative diagnosis and screening for this cancer. PSA in serum circulates under two forms (free PSA(fPSA) [3] and complexed,b eing the predominanto ne the complex with a 1-antichymotripsin (PSA-ACT) [4].I np rostate cancer diagnosis,t he sum of both forms noted total PSA (tPSA) is used to determine somec ut off.Avalue of tPSA above 10.0 ng/mL is regardeda sp ositive and indicates high probability of prostate cancer;b elow 4.0 ng/mL the result is considered negativea nd indicatesl ow probability of prostate cancer;b etween 4.0 ng/mL and 10 ng/mLt he result is in the so-called "grey zone" [5].T he quantitative detection of PSA has been carried out using optical methods including fluorescent labeling [6,7],s urface enhanced Raman scattering (SERS) [8],s urface Plasmon resonance (SPR) [9],o relectrochemicalm ethods [10][11][12].Point-of-care testing (POCT)i sn ecessary and thus traditional techniques utilizing highly expensive, immovable analytical equipment such as gas Chromatography-Mass Spectrometers are not feasible for sensing outside the laboratories [13-17] Screen-printing is aw ell establish technique for the reliable fabrication of robust biosensors, due to its low cost and applicability to mass production. Screen-printed electrodes (SPEs) in particular can combine ease of use and portability with simple,i nexpensive screen-printedt echniques and nowadays it can be found different designsoft his device [18][19][20][21][22].Despite manye fforts have been made in developing sensors for PSA detection, many challenges still need to be addressed such as their miniaturization, simplification of the fabrication steps and cost reduction.Magnetic beads (MBs)are used in bioassay with the capability to increase surface area to improve sensitivity [23].M ore important, MBs are easy to manipulate with the help of magnet and make possible the biological reaction events could be performed awayf rom the electrode surface [24],e ffectively reducing the complexity and time required for sensing application. Their use minimizes matrix effect due to washing and separation procedures and, since the beads are in suspension, allows faster assay kineticst ob ea chieved [25].M oreoverM Bs can be easily functionalized with differentl inkageg roups uch as streptavidin [26][27][28],t osyl groups [29][30][31][32], amino groups [33][34][35],a ntibodies or proteins [36][37][38][39].T he only problem represented by the use of the MBsi st hat the recognition elementisnot in direct contact with the surface electrode. To avoid this and to achieve greater sensitivity,i th as been proposed the use of magnetized electrode surface through either the inclusion in the electrode material of magneticp articles [40] or through the placement of small magnets below the surface of the working electrode [41,42].T his allows concentrating the MBs on the electrode surface for t...

Label‐free Voltammetric Immunosensor for Prostate Specific Antigen Detection

“…Lately, a lot of immunoassay methods related to PSA detection have been reported including enzyme‐linked immunosorbent‐assays (ELISA) , electrochemical immunoassays , chemiluminescent immunoassays and bioluminescent immunoassay . Although those methods are reliable, most of them require long measurement procedures, high costs, complex equipment, highly qualified personnel and are not appropriate for massive decentralized assays.…”

“…Table displays the electroanalytical characteristics of recent reported electrochemical immunosensor for PSA detection and those of the developed immunosensor. As it can be seen, the proposed immunosensor improves the width of the concentration range and the LOD in comparison with some of the recent reported sensors . Although other immunosensors show lower LOD that the achieved in this work (Table ), it has to be considered that the construction of these biosensors involves more complex schemes and higher costs (since more materials, reagents and/or steps are needed).…”

A novel electroconductive interface based on Fe3O4 magnetic nanoparticle and cysteamine functionalized AuNPs: Preparation and application as signal amplification element to minoring of antigen‐antibody immunocomplex and biosensing of prostate cancer

“…Compared with other immunosensors reported by analytical studies (Table ), the developed immunosensor showed better analytical performance in view of the linear range and the limit of detection. Such excellent sensing performance can be attributed following factors of (a) excellent conductivity and unique structural features Fe 3 O 4 , (b) large active surface area of Fe 3 O 4 modified electrode provides high density and a favorable microenvironment for oriented antibody immobilization retaining the biological activity, and (c) to further enhance the electrochemical signal, CysA‐AuNPs/TB labeled HRP‐Ab2 was used as a tracer for good catalytic reduction of [Fe (CN) 6 ] 3‐/4‐ .…”

“…Compared with other immunosensors reported by analytical studies (Table 1), [24][25][26][27][28][29]31 the developed immunosensor showed better analytical performance in view of the linear range and the limit of As shown in Figure S5, the current signal of the proposed immunosensor was compared with the current signal obtained in threefold excess of different interfering species. There are no significant changes in the signals observed, and the interference was nearly negligible, suggesting the acceptable selectivity of the fabricated immunosensor for the determination of PSA.…”

Electrochemical Biosensing in Cancer Diagnostics and Follow‐up

“…Biscay et al. investigated a screening device using magnetic beads as solid phase to develop an immunoassay for the detection of total PSA (tPSA) in serum. Here, the tPSA detection was performed by using superparamagnetic beads (1 mm) modified with streptavidin and an 8‐channel screen printed electrode array.…”