Early detection of cancer is vital for the successful treatment of the disease. Hence, a rapid and sensitive diagnosis is essential before the cancer is spread out to the other body organs. Here we ...describe the development of a point-of-care immunosensor for the detection of the cancer biomarker (total prostate-specific antigen, tPSA) using surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) sensor platforms in human serum samples. K D of the antibody used toward PSA was calculated as 9.46 × 10–10 M, indicating high affinity of the antibody used in developing the assay. By performing a sandwich assay using antibody-modified nanoparticles concentrations of 2.3 ng mL–1 (Au, 20 nm) and 0.29 ng mL–1 (8.5 pM) (Au, 40 nm) tPSA in 75% human serum were detected using the developed assay on an SPR sensor chip. The SPR sensor results were found to be comparable to that achieved using a QCM sensor platform, indicating that both systems can be applied for disease biomarkers screening. The clinical applicability of the developed immunoassay can therefore be successfully applied to patient’s serum samples. This demonstrates the high potential of the developed sensor devices as platforms for clinical prostate cancer diagnosis and prognosis.
Point-of-care diagnostic devices present a viable option for the rapid and sensitive detection and analysis of cancer markers. With the growing number of cancer cases being diagnosed worldwide and ...the increased number of fatalities due to late disease detection, biosensors can play an important role in the early diagnosis of cancer. Molecular profiles of patients are being increasingly studied using new molecular tools such as genomic and proteomic techniques. These methods combined with bioinformatics tools are generating new data which is being employed in the elucidation of new disease biomarkers. As with many disease conditions finding specific and sensitive markers that are associated with only one type of the disease can be difficult. In addition to this, the level of the biomarkers in biological fluids can vary depending on different disease conditions and stages. A number of molecular markers are therefore usually evaluated for cancer diagnosis and these can include proteins, peptides, over/under expression of gene markers and gene mutations. This review provides an overview of the biosensor technology available today, areas which are currently being developed and researched for cancer markers diagnosis—and a consideration of future prospects for the technology.
A surface plasmon resonance (SPR) sensor developed for the rapid, sensitive and specific detection of cardiac troponin T (cTnT) in serum samples is reported in this work. An extensive optimisation of ...assay parameters was conducted to achieve optimal detection strategy. Both direct and sandwich immunoassay formats were investigated and optimised. The response obtained was enhanced further by the use of gold nanoparticles (AuNPs) conjugated to the anti-cTnT detection antibody. A regeneration method was developed to enable the reuse of the SPR sensor for multiple sample application. The SPR immunosensor showed good reproducibility for cTnT detection in the concentration range of 25–1000ngmL−1 and 5–400ngmL−1 for the direct and sandwich assays in buffer, respectively. The linear regression analysis was performed and R2 value was found as 0.99 for both assays. In order to optimise the sensor for serum analysis, nonspecific binding of serum proteins was reduced through the use of additives in the dilution buffer. To achieve greater sensitivity, the performance of the cTnT immunosensor sandwich assay in human serum was evaluated using non-modified and AuNP modified detector antibodies. A detection limit (LOD) for the immunosensor in 50% serum was assessed as 5ngmL−1 cTnT for the standard sandwich assay and 0.5ngmL−1 cTnT when using AuNP conjugated detector antibodies with a linear dynamic range of 0.5–40ngmL−1. The dissociation constant was found as 3.28 × 10−9M using Langmuir binding model which indicates high affinity between cTnT and its antibody. The proposed SPR immunosensor has a promising potential to be developed for point-of-care testing for the early diagnosis of acute myocardial infarction (AMI). This method can also be used for the rapid detection of biomarkers in central nervous system diseases.
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•SPR sensor for Cardiac Troponin T monitoring is developed.•The use of fully automated biosensor system can play an important role in the diagnosis of acute myocardial infarction.•Development of highly specific and sensitive biosensor platform can aid in early detection.•The amplification of the sensor signal using nanoparticles help in achieving better sensitivity in 50% human serum.•The technology provides easy-to-use, reliable and cost-effective sensing tool.
The accidental contamination of Salmonella in raw and processed foods is a major problem for the food industry worldwide. At present many of the currently used methods for Salmonella detection are ...time and labour intensive. Therefore, rapid detection is a key to the prevention and identification of problems related to health and safety. This paper describes the application of a new quartz crystal microbalance (QCM) instrument with a microfluidic system for the rapid and real time detection of Salmonella Typhimurim. The QCMA-1 bare gold sensor chip which contain two sensing array was modified by covalently immobilising the monoclonal capture antibody on the active spot and a mouse IgG antibody on the control spot using a conventional amine coupling chemistry (EDC-NHS). The binding of the Salmonella cells onto the immobilised anti-Salmonella antibody alters the sensor frequency which was correlated to cells concentration in the buffer samples. Salmonella cells were detected using direct, sandwich, and sandwich assay with antibody conjugated gold-nanoparticles. The performance of the QCM immunosensor developed with gold-nanoparticles gave the highest sensitivity with a limit of detection (LOD) ~10–20 colony forming unit (CFU) ml−1 compared to direct and sandwich assay (1.83×102CFUml−1 and 1.01×102CFUml−1, respectively). The sensor showed good sensitivity and selectivity for Salmonella in the presence of other bacteria in real food samples and helped in reducing the pre-enrichment step, hence, demonstrating the potential of this technology for the rapid and sensitive microbial analysis.
Quartz crystal microbalance immunosensor for Salmonella Typhimurium Display omitted
•Immobilisation of biomolecules to sensor surface is a crucial step for biosensors sensitivity.•Development of a fully automated immunosensor based on QCM sensor chip for Salmonella detection enabled rapid analysis.•Use of gold nanoparticles enhanced the sensitivity of the QCM sensor.•Cross reactivity and specificity of the sensor signal in real food samples.
A quartz crystal microbalance (QCM) sensor platform was used to develop an immunosensor for the detection of food pathogen Campylobacter jejuni. Rabbit polyclonal antibodies and commercially ...available mouse monoclonal antibodies against C. jejuni were investigated to construct direct, sandwich and gold-nanoparticles (AuNPs) amplified sandwich assays. The performance of the QCM immunosensor developed using sandwich assay by utilising the rabbit polyclonal antibody as the capture antibody and conjugated to AuNPs as the detection antibody gave the highest sensitivity. This sensor achieved a limit of detection (LOD) of 150 colony forming unit (CFU)mL−1 of C. jejuni in solution. The QCM sensor showed excellent sensitivity and specificity for Campylobacter detection with low cross reactivity for other foodborne pathogens such as Salmonella Typhimurium, (7%) Listeria monocytogenes (3%) and Escherichia coli (0%). The development of this biosensor would help in the sensitive detection of Campylobacter which can result in reducing pre-enrichment steps; hence, reducing assay time. This work demonstrates the potential of this technology for the development of a rapid and sensitive detection method for C. jejuni.
•QCM sensor for Campylobacter detection has been developed.•A fully automated sensor can play a major role in diagnosing foodborne pathogens.•Highly specific, sensitive sensor platform can aid in early detection of C. jejuni.•Amplification of sensor signal with nanoparticles achieved high sensitivity.•The technology provides reliable and cost-effective sensing tool.
Molecularly imprinted polymers (MIPs) are artificial receptor ligands which can recognize and specifically bind to a target molecule. They are more resistant to chemical and biological damage and ...inactivation than antibodies. Therefore, target specific-MIP nanoparticles are aimed to develop and implemented to biosensors for the detection of biological toxic agents such as viruses, bacteria, and fungi toxins that cause many diseases and death due to the environmental contamination. For the first time, a molecularly imprinted polymer (MIP) targeting the bacteriophage MS2 as the template was investigated using a novel solid-phase synthesis method to obtain the artificial affinity ligand for the detection and removal of waterborne viruses through optical-based sensors. A high affinity between the artificial ligand and the target was found, and a regenerative MIP-based virus detection assay was successfully developed using a new surface plasmon resonance (SPR)-biosensor which provides an alternative technology for the specific detection and removal of waterborne viruses that lead to high disease and death rates all over the world.
•NanoMIPs were produced for target pharmaceutical.•MIPs capable of capturing target pharmaceutical diclofenac specifically.•A novel optical based sensor was developed for affinity based diclofenac ...assays.•LC–MS analysis confirmed high affinity results of the sensor.•A long shelf life was found for MIPs to capture its target.
Nanoparticles synthesised using molecular imprinting (MIP) with high affinity for diclofenac were produced and applied in the development of an optical sensor based on surface plasmon resonance (SPR). MIPs were synthesised with diclofenac as the template using solid-phase synthesis with photopolymerisation, a method which allows the template to be reused successfully. Particle size of ∼132.3nm±3.2 was achieved with low polydispersity index (0.1), which confirms the quality of the synthesised nanoMIPs. The MIPs were then immobilised on the surface of the SPR-2 gold sensor chips via covalent coupling using EDC/NHS. An affinity based-diclofenac assay was then constructed on the surface of the sensor. The diclofenac drug was then successfully detected in the concentration range of 1.24–80ngmL−1. The nanoMIP sensor surfaces were then regenerated using glycine–hydrochloric acid solution and reused for subsequent analysis indicating the stability of the sensor surface. Kinetic data analysis indicated a dissociation constant of 1.48×10−9M was achieved. Cross reactivity studies were conducted against other pharmaceuticals using the developed sensor. The nanoMIP affinity towards diclofenac was also confirmed by eluting a diclofenac solution through a solid phase–nanoMIP columns (SPE) and analysing the eluents using an LC–MS. The developed SPR sensor with the nanoMIP showed good potential for using the technology for the capture and detection of diclofenac in water.
In this work, two human epidermal growth factor receptors, HER-1 and HER-2, were selected as biomarkers to enable the detection of breast cancer. Therefore, two biosensors were developed using gold ...sensor chips coupled with amperometric detection of the enzyme label horse radish peroxidase (HRP). The biosensors/immunosensors relied on indirect sandwich enzyme-linked immunosorbent assays with monoclonal antibodies (Ab) against HER-1 and HER-2 attached to the sensors to capture the biomarkers. Detection polyclonal antibodies followed by secondary anti-rabbit (for HER-1) and anti-goat (for HER-2) IgG antibody-HRP were then applied for signal generation. In buffer, the developed sensors showed limits of detections (LOD) of 1.06 ng mL
and 0.95 ng mL
and limits of quantification (LOQ) of 2.1 ng mL
and 1.5 ng mL
for HER-1 and HER-2, respectively. In 100% (undiluted) serum, LODs of 1.2 ng mL
and 1.47 ng mL
and LOQs of 1.5 ng mL
and 2.1 ng mL
were obtained for HER-1 and HER-2, respectively. Such limits of detections are within the serum clinical range for the two biomarkers. Furthermore, gold nanoparticles (AuNP) labelled with secondary anti-rabbit and anti-goat IgG antibody-HRP were then used to enhance the assay signal and increase the sensitivity. In buffers, LODs of 30 pg mL
were seen for both sensors and LOQs of 98 pg mL
and 35 pg mL
were recorded for HER-1 and HER-2, respectively. For HER-2 the AuNPs biosensor was also tested in 100% serum obtaining a LOD of 50 pg mL
and a LOQ of 80 pg mL
. The HER-2 AuNP electrochemical immunosensor showed high specificity with very low cross-reactivity to HER-1. These findings demonstrate that the two developed sensors can enable early detection as well as monitoring of disease progression with a beneficial impact on patient survival and clinical outcomes.
Comparative and comprehensive investigations for adenovirus recognition and detection were conducted using plastic and natural antibodies to compare three different strategies. The implementation of ...molecularly imprinted polymer (MIP) technology for specific and sensitive recognition of viruses with the combination of biosensors was reported. Plastic antibodies (MIPs nanoparticles) were produced for adenovirus by employing a novel solid phase synthesis method. MIP receptors were then characterised using dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques prior to immobilisation on a surface plasmon resonance (SPR) sensor as affinity receptor for adenovirus detection. Two different templates were also imprinted as control MIPs (vancomycin-MIP and MS2-MIP). The specific recognition of adenovirus was investigated in the concentration range of 0.01–20pM and the limit of detection was achieved as 0.02pM. As an alternative to MIP receptors, direct and sandwich assays were developed for adenovirus quantification using natural antibodies. The detection limit of direct and sandwich assays were found as 0.3pM and 0.008pM, respectively. The kinetic data analyses were performed for three different adenovirus recognition methods and cross-reactivity studies were also conducted using MS2 phage as control virus and an excellent specificity was achieved with all assays types. This work confirmed the suitability of the MIPs SPR sensor for the detection of viruses.
•Plastic antibodies (MIPs) were synthesised for target virus (adenovirus) and controls.•MIPs capable of specific recognition and quantification of adenovirus.•Natural antibody-based arrays were developed as alternative methods.•High specificity and sensitivity were achieved with natural and plastic antibodies.•Successful implementation of virus-MIPs into an optical-based biosensor.
Universally, cardiovascular disease (CVD) is recognised as the prime cause of death with estimates exceeding 20 million by 2015 due to heart disease and stroke. Facts regarding the disease, its ...classification and diagnosis are still lacking. Hence, understanding the issues involved in its initiation, its symptoms and early detection will reduce the high risk of sudden death associated with it. Biosensors developed to be used as rapid screening tools to detect disease biomarkers at the earliest stage and able to classify the condition are revolutionising CVD diagnosis and prognosis.
Advances in interdisciplinary research areas have made biosensors faster, highly accurate, portable and environmentally friendly diagnostic devices. The recent advances in microfluidics and the advent of nanotechnology have resulted in the development of improved diagnostics through reduction of analysis time and integration of several clinical assays into a single, portable device as lab-on-a-chip (LOC). The development of such affinity based systems is a major drive of the rapidly growing nanotechnology industry which involves a multidisciplinary research effort encompassing nanofluidics, microelectronics and analytical chemistry. This review summarised the classification of CVD, the biomarkers used for its diagnosis, biosensors and their application including the latest developments in the field of heart-disease detection.
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•Heart diseases are the world׳s biggest killer; cause over 17.5 million deaths annually.•Biomarkers and biosensors are playing a crucial role in the diagnostic revolution of the disease.•Development of highly specific and sensitive biosensor platforms can provide early detection.•Simultaneous analysis of multiple markers using blood sample greatly enhances the applicability.•Technology provides miniaturised, easy-to-use, reliable and cost-effective sensing tools.
