Direct detection of carcinoembryonic antigen autoantibodies in clinical human serum samples using a surface plasmon resonance sensor

Promising Applications of Nanotechnology in Cancer Diagnostics and Therapeutics

Cancer is characterized by the accumulation of genetic mutations in cells by different types of mutagens such as physical, chemical, and biological. Consequently, normal cell cycles get interrupted. Conventional techniques used for diagnosis include. Various conventional techniques used for cancer diagnosis include immunological assays, histopathogical tests, polymerase chain reaction, computed tomography, magnetic resonance, radiation therapy, and many more. These techniques are expensive, time consuming, tedious, adverse effects to healthy cells and requirement of skilled personnel for their operation. Therefore nanomaterials based biosensors have been used for the sensitive, selective, economic and quick detection of cancer biomarkers. Electrochemical biosensors have shown profound impact in efficient diagnosis of cancers that facilitate the effective treatment of patient in acute stage. Nanomaterials including inorganic, organic and polymeric nanomaterials have been used in the treatment of different types of cancers. Nanoapproaches have offered several merits including site-specific, require traces amount of therapeutic molecules, limited toxicity, avoid drug resistance, more efficient, sensitive and reliable than conventional chemotherapeutics and radiation therapies. Therefore, future research should be focussed on development of highly inventive nanotools for the diagnosis and therapeutics of cancers.

Potential of surface plasmon resonance biosensors in cancer detection

A review is made of 71 papers on surface plasmon resonance biosensors, published between 2005 and 2020, mostly in the last decade. The reviewed papers are divided into two groups, depending on the validation of the developed biosensor. Validated biosensors are briefly characterized, while those that are not validated are listed in a table. Focus is placed on applications of SPR biosensors in testing the effectiveness of cancer markers and in the discovery of new cancer markers. Seven new markers are proposed, two of them having high sensitivity and diagnostic selectivity as determined by ROC curves. Papers concerning the determination of micro RNA and large particles such as vesicles, exosomes and cancer cells are also reviewed.

Construction of electrochemical aptasensor of carcinoembryonic antigen based on toehold-aided DNA recycling signal amplification

Carcinoembryonic antigen (CEA), serves as a broad-spectrum tumor marker, and plays an important role in reflecting the existence, therapeutic evaluation, development, monitoring and prognosis of many types of cancer. An electrochemical aptasensor was designed for CEA detection based on toehold-aided DNA recycling. A partially hybridized Probe-4 (i.e. P2/P3/P4) was self-assembled on the surface of a gold electrode serving as the sensing platform. For CEA detection, CEA can bind with aptamer and free probe-1 (P1) can hybridize with P4, triggering toehold-aided DNA recycling. This enables the hybridization of more probe-5 (P5) (labeled with methylene blue (MB)) with P4, causing more methylene blue (MB) to be brought close to the electrode surface. An amplified current signal was thus generated due to more MB in the electrode surface. The proposed design showed good linearity between current response and log CEA concentration ranging from 0.1 to 50 ng·mL^-1, with a detection limit of 20 pg mL^-1. This aptasensor also showed high specificity for CEA detection, and was successfully used in spiked biological samples.

A novel nitrogen and sulfur co-doped carbon dots-H2O2 chemiluminescence system for carcinoembryonic antigen detection using functional HRP-Au@Ag for signal amplification

A novel nitrogen and sulfur co-doped carbon dots (NS-CDs)-H₂O₂ chemiluminescence (CL) system was developed to detect carcinoembryonic antigen (CEA) by taking advantage of dual-signal amplification of functional Au@Ag nanoparticles (NPs) nanoprobes. Horseradish peroxidase (HRP) and the complementary DNA were co-immobilized onto Au@Ag NPs surface to shape the functional nanoprobes (HRP-Au@Ag-cDNA) for signal amplification. In this proposal, HRP-Au@Ag-cDNA was specifically hybridized with CEA aptamer-functionalized magnetic beads to form the double-strand hybridization nanocomposites (HRP-Au@Ag-dsDNA-MB). Upon the addition of CEA, the CEA aptamer preferred to bind with CEA instead of double-strand hybridization interaction, thus HRP-Au@Ag-dsDNA-MB was dehybridized and the HRP-Au@Ag-cDNA nanoprobe was released. The synergistic catalytic effects of HRP and Au @Ag NPs endow the nanoprobe producing a dual CL signal amplification in the NS-CDs-H₂O₂ CL system. The CL intensity of the developed strategy enhanced with CEA concentration increasing in the range of 0.3-80 ng mL^-1. Benefiting from the synergistic effect, a detection limit as low as 94 pg mL^-1 was obtained. Moreover, successful application of this CL sensing platform was achieved for the determination of CEA in human serum samples, demonstrating the promising prospect in the early tumor warning and therapeutic monitoring.

Protein functionalised self assembled monolayer based biosensor for colon cancer detection

We report results of the studies relating to the fabrication of a surface plasmon resonance (SPR) based label-free immunosensor for real-time monitoring of endothelin-1 (ET-1), a colon cancer biomarker. A gold disk modified with a self-assembled monolayer (SAM) of 11-mercaptoundecanoic acid (11-MUA) was functionalised via covalent immobilization of monoclonal anti-ET-1 antibodies using EDC-NHS (1-(3-(dimethylamine)-propyl)-3-ethylcarbodiimide hydrochloride, N-hydroxy succinimide) chemistry. This immunosensing platform (ethanolamine/anti-ET-1/11-MUA/Au) was characterized via atomic force microscopy (AFM), contact angle (CA) and Fourier transform infrared (FT-IR) spectroscopic techniques. The fabricated SPR electrode was further used to detect ET-1 in the broad concentration range 2-100 pg mL^-1, with a detection limit of 0.30 pg mL^-1 and remarkable sensitivity of 2.18 m^o pg^-1mL. The adsorption mechanism was studied using monophasic model and the values of association (k_a) and dissociation (k_d) constants for anti-ET-1 and ET-1 binding were calculated to be 4.4 ± 0.4 × 10⁵ M^-1 s^-1 and 2.04 ± 0.0003 × 10^-3 s^-1, respectively. The results obtained via analysis of serum samples of colorectal cancer patients were found to be in good agreement with those obtained from enzyme-linked immunosorbent assay (ELISA) technique. Further, electrochemical studies were performed to prove the efficacy of the fabricated platform as a point of care device for the detection of ET-1.

Screening and Biosensor-Based Approaches for Lung Cancer Detection

Early diagnosis of lung cancer helps to reduce the cancer death rate significantly. Over the years, investigators worldwide have extensively investigated many screening modalities for lung cancer detection, including computerized tomography, chest X-ray, positron emission tomography, sputum cytology, magnetic resonance imaging and biopsy. However, these techniques are not suitable for patients with other pathologies. Developing a rapid and sensitive technique for early diagnosis of lung cancer is urgently needed. Biosensor-based techniques have been recently recommended as a rapid and cost-effective tool for early diagnosis of lung tumor markers. This paper reviews the recent development in screening and biosensor-based techniques for early lung cancer detection.

Antibody to human α-fetoprotein inhibits cell growth of human hepatocellular carcinoma cells by resuscitating the PTEN molecule: in vitro experiments

It has been proposed that α-fetoprotein (AFP) is a new member of the intracellular signaling molecule family of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway via interaction with the phosphatase and tensin homolog (PTEN). In this study, the effects of anti-human AFP antibody on the functions of PTEN were examined using an AFP-producing human hepatoma cell line. The antibody caused significant inhibition of cell growth, compared to a normal IgG control, with the accumulation of intracellular immune complexes followed by significant reduction of cytosolic functional AFP. Decrease in the amount of AKT phosphorylated on serine (S) 473 indicated that PI3K/AKT signaling was suppressed in the cells. S380-phosphorylated PTEN increased markedly by the second day after antibody treatment, with slight but significant increase in the PTEN protein level. Since phosphorylation at S380 is critical for PTEN stability, the increase in S380-phosphorylated PTEN indicated maintenance of the number of PTEN molecules and the related potential to control PI3K/AKT signaling. p53 protein (P53) significantly, but slightly increased during antibody treatment, because PTEN expression increased the stability and function of P53 via both molecular interactions. P53 phosphorylated at S20 or at S392 dramatically increased, suggesting an increase in the stability, accumulation and activation of P53. Glucose transporter 1 (GLUT1) increased immediately after antibody treatment, pointing to a deficiency of glucose in the cells. Immunofluorescence cytology revealed that antibody-treatment re-distributed GLUT1 molecules throughout the cytoplasm with a reduction of their patchy localization on the cell surface. This suggested that translocation of GLUT1 depends on the PI3K/AKT pathway, in particular on PTEN expression. Antibody therapy targeted at AFP-producing tumor cells showed an inhibitory effect on the PI3K/AKT pathway via the liberation, restoration and functional stabilization of PTEN. PTEN simultaneously induced both P53 activation and intracellular translocation of GLUT1, since these are closely associated with PTEN.

Preventive DNA vaccination against CEA-expressing tumors with anti-idiotypic scFv6.C4 DNA in CEA-expressing transgenic mice

Carcinoembryonic antigen (CEA) is expressed during embryonic life and in low level during adult life. Consequently, the CEA is recognized by the immune system as a self-antigen and thus CEA-expressing tumors are tolerated. Previously, we constructed a single chain variable fragment using the 6.C4 (scFv6.C4) hybridoma cell line, which gave rise to antibodies able to recognize CEA when C57/Bl6 mice were immunized. Here, the scFv6.C4 ability to prevent the CEA-expressing tumor growth was assessed in CEA-expressing transgenic mice CEA2682. CEA2682 mice immunized with the scFv6.C4 expressing plasmid vector (uP/PS-scFv6.C4) by electroporation gave rise to the CEA-specific AB3 antibody after the third immunization. Sera from immunized mice reacted with CEA-expressing human colorectal cell lines CO112, HCT-8, and LISP-1, as well as with murine melanoma B16F10 cells expressing CEA (B16F10-CEA). Cytotoxic T lymphocytes (CTL) from uP/PS-scFv6.C4 immunized mice lysed B16F10-CEA (56.7%) and B16F10 expressing scFv6.C4 (B16F10-scFv6.C4) (46.7%) cells, against CTL from uP-immunized mice (10%). After the last immunization, 5 × 105 B16F10-CEA cells were injected into the left flank. All mice immunized with the uP empty vector died within 40 days, but uP/PS-scFv6.C4 vaccinated mice (40%) remained free of tumor for more than 100 days. Splenocytes obtained from uP/PS-scFv6.C4 vaccinated mice showed higher T-cell proliferative activity than those from uP vaccinated mice. Collectively, DNA vaccination with the uP-PS/scFv6.C4 plasmid vector was able to give rise to specific humoral and cellular responses, which were sufficient to retard growth and/or eliminate the injected B16F10-CEA cells.

Detection of antibodies against hepatitis B virus surface antigen and hepatitis C virus core antigen in plasma with a waveguide-mode sensor

In large-scale disasters, such as huge significant earthquakes, on-site examination for blood typing and infectious disease screening will be very helpful to save lives of victims who need surgical treatment and/or blood transfusion. However, physical damage, such as building collapse, electric power failure and traffic blockage, disrupts the capacity of the medical system. Portable diagnostic devices are useful in such cases of emergency. In this study, we evaluated a waveguide-mode sensor for detection of anti-hepatitis virus antibodies. First, we examined whether we can detect antigen-antibody interaction on a sensor chip immobilized hepatitis B virus surface (HBs) antigen and hepatitis C virus (HCV) core antigen using monoclonal mouse antibodies for HBs antigen and HCV core antigen. We obtained significant changes in the reflectance spectra, which indicate specific antigen-antibody interaction for anti-HBs antibody and anti-HCV antibody. Next, we examined the effect of horseradish peroxidase-conjugated secondary antibody using aminoethyl carbazole as the peroxidase substrate and found that the colorimetric reaction increases detection sensitivity for anti-HBs antibody more than 300 times. Finally, we successfully detected anti-HBs antibody in human blood samples with an enhancing method using a peroxidase reaction. Thus, a portable device utilizing a waveguide-mode sensor may be applied to on-site blood testing in emergency settings.

Surface Plasmon Resonance Clinical Biosensors for Medical Diagnostics

The design and application of sensors for monitoring biomolecules in clinical samples is a common goal of the sensing research community. Surface plasmon resonance (SPR) and other plasmonic techniques such as localized surface plasmon resonance (LSPR) and imaging SPR are reaching a maturity level sufficient for their application in monitoring biomolecules in clinical samples. In recent years, the first examples for monitoring antibodies, proteins, enzymes, drugs, small molecules, peptides, and nucleic acids in biofluids collected from patients afflicted with a series of medical conditions (Alzheimer's, hepatitis, diabetes, leukemia, and cancers such as prostate and breast cancers, among others) demonstrate the progress of SPR sensing in clinical chemistry. This Perspective reviews the current status of the field, showcasing a series of early successes in the application of SPR for clinical analysis and detailing a series of considerations regarding sensing schemes, exposing issues with analysis in biofluids, and comparing SPR with ELISA, while providing an outlook of the challenges currently associated with plasmonic materials, instrumentation, microfluidics, bioreceptor selection, selection of a clinical market, and validation of a clinical assay for applying SPR sensors to clinical samples. Research opportunities are proposed to further advance the field and transition SPR biosensors from research proof-of-concept stage to actual clinical applications.

Discovery and Validation of Agonistic Angiotensin Receptor Autoantibodies as Biomarkers of Adverse Outcomes

BACKGROUND

Agonistic angiotensin II type 1 receptor autoantibodies (AT1RaAbs) have not been associated with functional measures or risk for adverse health outcomes. AT1RaAbs could be used to stratify patient risk and to identify patients who can benefit from angiotensin receptor blocker treatment.

METHODS

Demographic and physiological covariates were measured in a discovery set of community-dwelling adults from Baltimore (N=255) and AT1RaAb associations with physical function tests and outcomes assessed. A group from Chicago (N=60) was used for validation of associations and to explore the impact of angiotensin receptor blocker treatment.

RESULTS

The Baltimore group had 28 subjects with falls, 32 frail subjects, and 5 deaths. Higher AT1RaAbs correlated significantly with interleukin-6 (Spearman r=0.33, P<0.0001), systolic blood pressure (Spearman r=0.28, P<0.0001), body mass index (Spearman r=0.28, P<0.0001), weaker grip strength (Spearman r=-0.34, P<0.01), and slower walking speed (Spearman r=-0.30, P<0.05). Individuals with high AT1RaAbs were 3.9 (95% confidence interval, 1.38-11.0) times more likely to be at high risk after adjusting for age (P<0.05). Every 1 µg/mL increase in AT1RaAbs increased the odds of falling 30% after adjusting for age, sex, body mass index, and blood pressure. The Chicago group had 46 subjects with falls and 60 deaths. Serum AT1RaAb levels were significantly correlated with grip strength (Spearman r=-0.57, P<0.005), walking speed (Spearman r=-0.47, P<0.005), and falls (Spearman r=0.30, P<0.05). Every 1 µg/mL increase in AT1RaAbs, decreased time to death by 9% after adjusting for age, sex, body mass index, and blood pressure. Chronic treatment with angiotensin receptor blockers was associated with better control of systolic blood pressure and attenuation of decline in both grip strength and time to death.

CONCLUSIONS

In older individuals, higher AT1RaAb levels were associated with inflammation, hypertension, and adverse outcomes. Angiotensin receptor blocker treatment may blunt the harm associated with high levels of AT1RaAb.

Emerging microfluidic devices for cancer cells/biomarkers manipulation and detection

Circulating tumour cells (CTCs) are active participants in the metastasis process and account for ∼90% of all cancer deaths. As CTCs are admixed with a very large amount of erythrocytes, leukocytes, and platelets in blood, CTCs are very rare, making their isolation, capture, and detection a major technological challenge. Microfluidic technologies have opened-up new opportunities for the screening of blood samples and the detection of CTCs or other important cancer biomarker-proteins. In this study, the authors have reviewed the most recent developments in microfluidic devices for cells/biomarkers manipulation and detection, focusing their attention on immunomagnetic-affinity-based devices, dielectrophoresis-based devices, surface-plasmon-resonance microfluidic sensors, and quantum-dots-based sensors.

Fluorescence resonance energy transfer biosensor between upconverting nanoparticles and palladium nanoparticles for ultrasensitive CEA detection

An ultrasensitive biosensor for carcinoembryonic antigen (CEA) was constructed based on fluorescence resonance energy transfer (FRET) between upconverting nanoparticles (UCPs) and palladium nanoparticles (PdNPs). PdNPs was synthesized by the addition of a solution of Na2PdCl4 into a mixture of N2H4·H2O as the reducing agent and 11-mercaptoundecanoic acid (MUDA) as the stabilizer. The CEA aptamer (5'-NH2-ATACCAGCTTATTCAATT-3') was conjugated to hexanedioic acid (HDA) modified UCPs (HDA-UCPs) through an EDC-NHS coupling protocol. The coordination interaction between nitrogen functional groups of the CEA aptamer and PdNPs brought UCPs and PdNPs in close proximity, which resulted in the fluorescence quenching of UCPs to an extent of 85%. And the non-specific fluorescence quenching caused by PdNPs towards HDA-UCPs was negligible. After the introduction of CEA into the UCPs-CEA aptamer-PdNPs fluorescence quenching system, the CEA aptamer preferentially combined with CEA accompanied by the conformational change which weakened the coordination interaction between the CEA aptamer and PdNPs. So fluorescence recovery of UCPs was observed and a linear relationship between the fluorescence recovery of UCPs and the concentration of CEA was obtained in the range from 2pg/mL to 100pg/mL in the aqueous buffer with the detection limit of 0.8pg/mL. The ultrasensitive detection of CEA was also realized in diluted human serum with a linear range from 4pg/mL to 100pg/mL and a detection limit of 1.7pg/mL. This biosensor makes the most of the high quenching ability of PdNPs towards UCPs with negligible non-specific fluorescence quenching and has broad application prospects in biochemistry.

Significance of Rumex vesicarius as anticancer remedy against hepatocellular carcinoma: a proposal-based on experimental animal studies

Rumex vesicarius is an edible herb distributed in Egypt and Saudi Arabia. The whole plant has significant value in folk medicine and it has been used to alleviate several diseases. Hepatocellular carcinoma (HCC), the major primary malignant tumor of the liver, is one of the most life-threatening human cancers. The goal of the current study was to explore the potent role of Rumex vesicarius extract against HCC induced in rats. Thirty adult male albino rats were divided into 3 groups: (I): Healthy animals received orally 0.9% normal saline and served as negative control group, (II): HCC group in which rats were orally administered N-nitrosodiethylamine NDEA, (III): HCC group treated orally with R. vesicarius extract in a dose of 400 mg/kg b.wt daily for two months. ALT and AST, ALP and γ-GT activities were estimated. CEA, AFP, AFU, GPC-3, Gp-73 and VEGF levels were quantified. Histopathological examination of liver tissue sections was also carried out. The results of the current study showed that the treatment of the HCC group with R. vesicarius extract reversed the significant increase in liver enzymes activity, CEA, AFP, AFU, glypican 3, golgi 73 and VEGF levels in serum as compared to HCC-untreated counterparts. In addition, the favorable impact of R. vesicarius treatment was evidenced by the marked improvement in the histopathological features of the liver of the treated group. In conclusion, the present experimental setting provided evidence for the significance of R. vesicarius as anticancer candidate with a promising anticancer potential against HCC. The powerful hepatoprotective properties, the potent antiangiogenic activity and the effective antiproliferative capacity are responsible for the anticancer effect of this plant.

Effects of bipyramidal gold nanoparticles and gold nanorods on the detection of immunoglobulins

The influence of different shapes of gold nanoparticles and techniques (SPR and SWV) on the sensitivity of biosensors was investigated, using IgG detection as a model system.

Choosing a suitable method for the identification of replication origins in microbial genomes

As the replication of genomic DNA is arguably the most important task performed by a cell and given that it is controlled at the initiation stage, the events that occur at the replication origin play a central role in the cell cycle. Making sense of DNA replication origins is important for improving our capacity to study cellular processes and functions in the regulation of gene expression, genome integrity in much finer detail. Thus, clearly comprehending the positions and sequences of replication origins which are fundamental to chromosome organization and duplication is the first priority of all. In view of such important roles of replication origins, tremendous work has been aimed at identifying and testing the specificity of replication origins. A number of computational tools based on various skew types have been developed to predict replication origins. Using various in silico approaches such as Ori-Finder, and databases such as DoriC, researchers have predicted the locations of replication origins sites for thousands of bacterial chromosomes and archaeal genomes. Based on the predicted results, we should choose an effective method for identifying and confirming the interactions at origins of replication. Here we describe the main existing experimental methods that aimed to determine the replication origin regions and list some of the many the practical applications of these methods.

Surface plasmon resonance: advances of label-free approaches in the analysis of biological samples

Surface plasmon resonance sensors have made vast advancements in the sensing technology and the number of applications achievable. New developments in surface plasmon resonance sensors have gained considerable momentum promoted by the urgent needs of fast, reliable and label-free methods for detection and quantification of analytes in molecular biology, medicine and other life sciences. However, even if enormous improvements in the limits of detections have been achieved, this technology still faces important challenges to be translated to clinical practice or in-field measurements. This paper reviews the important recent advances of this technology for the label-free detection in real biological samples and we discussed the key challenges to be overcome to transit from prototypes to commercial biosensors.

Detection of Bacillus thuringiensis Cry1Ab protein based on surface plasmon resonance immunosensor

Two novel surface plasmon resonance immunosensors were fabricated for detection of the Bacillus thuringiensis Cry1Ab protein and to demonstrate their performance in analyzing Cry1Ab protein in crop samples. Sensor 2 was modified by 1,6-hexanedithiol, Au/Ag alloy nanoparticles, 3-mercaptopropionic acid, and protein A (or not [sensor 1]), with Cry1Ab monoclonal antibody. As a result, both of the immunosensors exhibited satisfactory linear responses in the Cry1Ab protein concentration ranges of 10 to 500ngml(-1) and 8 to 1000ngml(-1), and the detection limits were 5.0 and 4.8ngml(-1), respectively. The immunosensors possessed good specificity and acceptable reproducibility. In addition, crop samples could be analyzed after a simple treatment. The transgenic crops could be easily identified from the conventional ones by the two immunosensors.

Recent advances in application of biosensors in tissue engineering

Biosensors research is a fast growing field in which tens of thousands of papers have been published over the years, and the industry is now worth billions of dollars. The biosensor products have found their applications in numerous industries including food and beverages, agricultural, environmental, medical diagnostics, and pharmaceutical industries and many more. Even though numerous biosensors have been developed for detection of proteins, peptides, enzymes, and numerous other biomolecules for diverse applications, their applications in tissue engineering have remained limited. In recent years, there has been a growing interest in application of novel biosensors in cell culture and tissue engineering, for example, real-time detection of small molecules such as glucose, lactose, and H2O2 as well as serum proteins of large molecular size, such as albumin and alpha-fetoprotein, and inflammatory cytokines, such as IFN-g and TNF-α. In this review, we provide an overview of the recent advancements in biosensors for tissue engineering applications.

Surface plasmon resonance applications in clinical analysis

In the last 20 years, surface plasmon resonance (SPR) and its advancement with imaging (SPRi) emerged as a suitable and reliable platform in clinical analysis for label-free, sensitive, and real-time monitoring of biomolecular interactions. Thus, we report in this review the state of the art of clinical target detection with SPR-based biosensors in complex matrices (e.g., serum, saliva, blood, and urine) as well as in standard solution when innovative approaches or advanced instrumentations were employed for improved detection. The principles of SPR-based biosensors are summarized first, focusing on the physical properties of the transducer, on the assays design, on the immobilization chemistry, and on new trends for implementing system analytical performances (e.g., coupling with nanoparticles (NPs). Then we critically review the detection of analytes of interest in molecular diagnostics, such as hormones (relevant also for anti-doping control) and biomarkers of interest in inflammatory, cancer, and heart failure diseases. Antibody detection is reported in relation to immune disorder diagnostics. Subsequently, nucleic acid targets are considered for revealing genetic diseases (e.g., point mutation and single nucleotides polymorphism, SNPs) as well as new emerging clinical markers (microRNA) and for pathogen detection. Finally, examples of pathogen detection by immunosensing were also analyzed. A parallel comparison with the reference methods was duly made, indicating the progress brought about by SPR technologies in clinical routine analysis.

Anti-vascular endothelial growth factor receptor (VEGFR) 2 autoantibody identification in glioblastoma patient using single B cell-based antibody gene cloning

Antibody direct cloning from single B cells is simple and efficient and has been successful in antibody identification of infectious diseases. However, although a recent whole-exome sequencing revealed abundant heterogeneic mutation accumulation in cancers, identification and synthesis of autoantibodies against specific cancer-associated antigens is still difficult in cancer patients owing to the very small number of B cells producing autoantibodies. In the present study, to identify autoantibodies targeting tumor antigens, we measured the titer of autoantibodies in high-grade glioma patients' plasma and identified two patients with elevated autoantibodies to a few transmembrane proteins. Specific B cells producing autoantibody against vascular endothelial growth factor receptor (VEGFR) 2 were immunostained with labeled protein and anti-human IgG antibody, and then collected by a single cell sorter. Finally, 22 antibody genes were successfully identified using direct IgG cloning from single B cell mRNA, and two antibody clones were found to have significant VEGFR2-specific binding affinity. The current direct human IgG gene cloning technique for identifying human antibodies derived from IgG-memory B cells avoids time-consuming procedures such as phage display-based antibody-library screening, and therefore may be applicable to identifying human autoantibodies in a variety of disorders including cancers even when antibody elevation is not detected because of a very small number of memory B cells.

Preparation of graphene oxide-based surface plasmon resonance biosensor with Au bipyramid nanoparticles as sensitivity enhancer

A sensitive and selective wavelength-modulation surface plasmon resonance (SPR) biosensor based on graphene oxide (GO) and Au bipyramids (AuBPs) is reported for determination of bovine IgM. GO sheets with lengths of 100-300 nm are synthesized and assembled on amine-modified Au film. The large surface area and abundant functional groups of GO allow the efficient immobilization of antibody. AuBPs are nanoparticles with a penta-twinned crystal structure, which have a sharp localized surface plasmon resonance (LSPR) band because of their high monodispersity. In the optimal conditions, the GO-based biosensor with AuBPs as sensitivity enhancers shows a satisfactory response to bovine IgM in the concentration range of 0.03-32 μg mL(-1). For contrast, traditional biosensor, GO-based biosensor and GO-based biosensor with Au nanorods (AuNRs) as sensitivity enhancers for antigen detection were also investigated. Consequently, the as-prepared GO sheets function as promising support for antibody and GO-based SPR biosensor using AuBPs as enhancers has the highest sensitivity among the four types of biosensors.

Non-specific adsorption of crude cell lysate on surface plasmon resonance sensors

Non-specific adsorption of the molecular components of biofluids is ubiquitous in the area of biosensing technologies, severely limiting the use of biosensors in real-world applications. The surface chemistries developed to prevent non-specific adsorption of crude serum are not necessarily suited for sensing in other biosamples. In particular, the diagnostic potential of differential expression of proteins in tissues makes cell lysate attractive for disease diagnostics using solid biopsies. However, crude cell lysate poses a significant challenge for surface chemistries because of a large concentration of highly adherent lipids. Contrary to the non-specific adsorption in crude serum being suppressed by hydrophilic surfaces, the surface plasmon resonance (SPR) analysis of serine-, aspartic-acid-, histidine-, leucine-, and phenylalanine-based peptide monolayers revealed that hydrophobic and positively charged peptides decreased non-specific adsorption when using lysate from HEK 293FT cells. A polyethylene glycol (PEG) monolayer resulted in 2-fold greater fouling than the best peptide [3-MPA-(His)2(Leu)2(Phe)2-OH] under the same conditions. Matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry (MALDI-TOF/TOF MS) analysis of the adsorbate from cell lysate confirmed that lipids are the main source of non-specific adsorption. Importantly, the mass spectrometry (MS) study revealed that both the number of lipids identified and their intensity decreased with decreasing non-specific adsorption. A peptide monolayer thus provides an efficient mean to suppress non-specific adsorption from this human cell lysate.

Early lung cancer diagnosis by biosensors

Lung cancer causes an extreme threat to human health, and the mortality rate due to lung cancer has not decreased during the last decade. Prognosis or early diagnosis could help reduce the mortality rate. If microRNA and tumor-associated antigens (TAAs), as well as the corresponding autoantibodies, can be detected prior to clinical diagnosis, such high sensitivity of biosensors makes the early diagnosis and prognosis of cancer realizable. This review provides an overview of tumor-associated biomarker identifying methods and the biosensor technology available today. Laboratorial researches utilizing biosensors for early lung cancer diagnosis will be highlighted.

Changes of Serum Trace Elements, AFP, CEA, SF, T3, T4 and IGF-II in Different Periods of Rat Liver Cancer

OBJECTIVE

Based on liver cancer model built in SD rats, the contents of trace elements (Cu, Fe, Zn, Ca and Mg), AFP, CEA, SF, TH and IGF-II in serum were measured at different stages to explore the molecular changes during the rat liver cancer development.

METHODS

The SD rat liver cancer model was built by using diethylnitrosamine (DENA) as the mutagen. During 16 weeks of DENA gavage, blood samples were taken in the 14th, 28th, 56th, 77th, 105th and 112th days respectively after the first day of gavage with DENA, then the contents of five trace elements (Cu, Fe, Zn, Ca and Mg), T3, T4, IGF-II, AFP, CEA and SF in serum were determined.

RESULTS

During the development of the rat liver cancer, in the test group, the Cu content significantly increased in serum, while the contents of Fe, Zn and Ca significantly decreased. The content of Mg showed no significant change. AFP and CEA of the test group showed same expression level with the control group; while the content of SF was lower than that of the control group when cancerization appeared. T3 and T4 increased at the first stage and then went down, and the content of IGF-II was always high.

CONCLUSION

Cu, Fe, Zn, Ca, T3, T4, SF and IGF-II are closely related to the development of liver cancer. The changes of their contents in the development of cancer could enlighten the researches on cancer pathogenesis and prevention.

Development of a novel two dimensional surface plasmon resonance sensor using multiplied beam splitting optics

A novel two dimensional surface plasmon resonance (SPR) sensor system with a multi-point sensing region is described. The use of multiplied beam splitting optics, as a core technology, permitted multi-point sensing to be achieved. This system was capable of simultaneously measuring nine sensing points. Calibration curves for sucrose obtained on nine sensing points were linear in the range of 0–10% with a correlation factor of 0.996–0.998 with a relative standard deviation of 0.090–4.0%. The detection limits defined as S/N = 3 were 1.98 × 10⁻⁶–3.91 × 10⁻⁵ RIU. This sensitivity is comparable to that of conventional SPR sensors.

Protein analytical assays for diagnosing, monitoring, and choosing treatment for cancer patients

Cancer treatment is often hindered by inadequate methods for diagnosing the disease or insufficient predictive capacity regarding therapeutic efficacy. Targeted cancer treatments, including Bcr-Abl and EGFR kinase inhibitors, have increased survival for some cancer patients but are ineffective in other patients. In addition, many patients who initially respond to targeted inhibitor therapy develop resistance during the course of treatment. Molecular analysis of cancer cells has emerged as a means to tailor treatment to particular patients. While DNA analysis can provide important diagnostic information, protein analysis is particularly valuable because proteins are more direct mediators of normal and diseased cellular processes. In this review article, we discuss current and emerging protein assays for improving cancer treatment, including trends toward assay miniaturization and measurement of protein activity.

Proteomic technologies for the study of osteosarcoma

Osteosarcoma is the most common primary bone cancer of children and is established during stages of rapid bone growth. The disease is a consequence of immature osteoblast differentiation, which gives way to a rapidly synthesized incompletely mineralized and disorganized bone matrix. The mechanism of osteosarcoma tumorogenesis is poorly understood, and few proteomic studies have been used to interrogate the disease thus far. Accordingly, these studies have identified proteins that have been known to be associated with other malignancies, rather than being osteosarcoma specific. In this paper, we focus on the growing list of available state-of-the-art proteomic technologies and their specific application to the discovery of novel osteosarcoma diagnostic and therapeutic targets. The current signaling markers/pathways associated with primary and metastatic osteosarcoma that have been identified by early-stage proteomic technologies thus far are also described.

Proteomic technologies for the identification of disease biomarkers in serum: advances and challenges ahead

Serum is an ideal biological sample that contains an archive of information due to the presence of a variety of proteins released by diseased tissue, and serum proteomics has gained considerable interest for the disease biomarker discovery. Easy accessibility and rapid protein changes in response to disease pathogenesis makes serum an attractive sample for clinical research. Despite these advantages, the analysis of serum proteome is very challenging due to the wide dynamic range of proteins, difficulty in finding low-abundance target analytes due to the presence of high-abundance serum proteins, high levels of salts and other interfering compounds, variations among individuals and paucity of reproducibility. Sample preparation introduces pre-analytical variations and poses major challenges to analyze the serum proteome. The label-free detection techniques such as surface plasmon resonance, microcantilever, few nanotechniques and different resonators are rapidly emerging for the analysis of serum proteome and they have exhibited potential to overcome few limitations of the conventional techniques. In this article, we will discuss the current status of serum proteome analysis for the biomarker discovery and address key technological advancements, with a focus on challenges and amenable solutions.

Fe3O4 nanoparticles-enhanced SPR sensing for ultrasensitive sandwich bio-assay

Magnetic nanoparticles (MNPs) have been receiving increasing attention because of its great potentials in bioseparation. However, the separation products are difficult to be detected by general method due to their extremely small size. Here, we demonstrate that MNPs can greatly enhance the signal of surface plasmon resonance spectroscopy (SPR). Features of MNPs-aptamer conjugates as a powerful amplification reagent for ultrasensitive immunoassay are reported in this work for the first time. In order to evaluate the sensing ability of MNPs-aptamer conjugates as an amplification reagent, a sandwich SPR sensor is constructed by using thrombin as model analyte. Thrombin, captured by immobilized anti-thrombin aptamer on SPR gold film, is sensitively detected by SPR spectroscopy with a lowest detection limit of 0.017 nM after MNPs-aptamer conjugates is used as amplification reagent. At the same time, the excellent selectivity of the present biosensor is also confirmed by using three kinds of proteins (BSA, human IgM and human IgE) as controls. These results confirm that MNPs is a powerful sandwich element and an excellent amplification reagent for SPR based sandwich immunoassay and SPR has a great potential for the detection of MNPs-based bioseparation products.

Biosensors for diagnostic applications

Biosensors combine a transducer with a biorecognition element and thus are able to transform a biochemical event on the transducer surface directly into a measurable signal. By this they have the potential to provide rapid, real-time, and accurate results in a comparatively easy way, which makes them promising analytical devices. Since the first biosensor was introduced in 1962 as an "enzyme electrode" for monitoring glucose in blood, medical applications have been the main driving force for further biosensor development. In this chapter we outline potential biosensor setups, focusing on transduction principles, biorecognition layers, and biosensor test formats, with regard to potential applications. A summary of relevant aspects concerning biosensor integration in efficient analytical setups is included. We describe the latest applications of biosensors in diagnostic applications focusing on detection of molecular biomarkers in real samples. An overview of the current state and future trends of biosensors in this field is given.

Serum-based ALYGNSA immunoassay for the prostate cancer biomarker, total prostate-specific antigen (tPSA)

Prostate-specific antigen (PSA) is a serum glycoprotein overproduced by the prostate in prostate cancer (> or = 4 ng/mL in the bloodstream). An immunoassay for total PSA (tPSA) was developed using the ALYGNSA method to enhance capture antibody orientation and a limit of detection of 0.63 ng/mL was reported, a limit 15-fold lower than a commercial tPSA ELISA assay. This ALYGNSA assay, however, was performed using only buffer-based proteins and blocking agents (Mackness et al., Anal Bioanal Chem 396:681-686, 2010). To improve the clinical application of this system, a serum-based tPSA ALYGNSA was developed employing human serum. This assay also resulted in a limit of detection of 0.63 ng/mL of tPSA protein. The findings reported here provide support for the clinical application of this assay for diagnosis, progression, treatment, and possible recurrence of prostate cancer.