Measurement of serum prostate cancer markers using a nanopore thin film based optofluidic chip

Predicting the Diagnosis of Prostate Cancer with a Novel Blood-Based Biomarker: Comparison of Its Performance with Prostate-Specific Antigen

The purpose of this study was to assess the efficacy, specificity, and predictive value of a newly discovered biomarker, Zinc finger-like1 protein (referred to as neuroendocrine marker, NEM) for the detection of prostate cancer (PCa). We retrospectively analyzed banked plasma samples from 508 men, with a median age of 67 years (range 48-97), to compare the performance of NEM and PSA in predicting subsequent histologic PCa. The cohort consisted of four groups of patients visiting a urology clinic: (1) patients not diagnosed with either benign prostatic disease or prostate cancer (PCa) were defined as normal; (2) patients diagnosed with benign hyperplasia (BPH) but not PCa; (3) patients with confirmed PCa; and (4) patients with cancer other than PCa. The normal men displayed a mean NEM plasma level of 0.948 ± 0.051 ng/mL, which increased to 1.813 ± 0.315 ng/mL in men with BPH, 86.49 ± 15.51 ng/mL in men with PCa, and 10.47 ± 1.029 ng/mL in men with other Ca. The corresponding concentrations of prostate-specific antigen (PSA) in these subjects were 1.787 ± 0.135, 5.405 ± 0.699, 35.77 ± 11.48 ng/mL, and 8.036 ± 0.518, respectively. Receiver operating characteristic (ROC) curve analysis was performed to compare NEM and PSA performance, and the Jouden Index for each biomarker was calculated to determine cut-off points for each biomarker. The area under the ROC curve to predict PCa was 0.99 for NEM and 0.81 for PSA (p < 0.0001). The cut-off for NEM was at 1.9 ng/mL, with sensitivity of 98% and specificity of 97%. The corresponding PSA values were 4.4 ng/mL, with sensitivity of 76% and specificity of 95%. The predictive value of each biomarker in a patient was matched with his pathologic data to determine the accuracy of each biomarker. NEM was more accurate than PSA in differentiating cancer from benign conditions, such as BPH or prostatitis. In conclusion, NEM was a better predictor of PCa than PSA in patients visiting urology clinics. NEM tests, either alone or in conjunction with other biomarkers, provide a reliable, non-invasive, and inexpensive test to remarkably reduce false positives and thereby reduce the number of diagnostic biopsies and associated painful procedures and the loss of quality of life.

Detection of Biological Molecules Using Nanopore Sensing Techniques

Modern biomedical sensing techniques have significantly increased in precision and accuracy due to new technologies that enable speed and that can be tailored to be highly specific for markers of a particular disease. Diagnosing early-stage conditions is paramount to treating serious diseases. Usually, in the early stages of the disease, the number of specific biomarkers is very low and sometimes difficult to detect using classical diagnostic methods. Among detection methods, biosensors are currently attracting significant interest in medicine, for advantages such as easy operation, speed, and portability, with additional benefits of low costs and repeated reliable results. Single-molecule sensors such as nanopores that can detect biomolecules at low concentrations have the potential to become clinically relevant. As such, several applications have been introduced in this field for the detection of blood markers, nucleic acids, or proteins. The use of nanopores has yet to reach maturity for standardization as diagnostic techniques, however, they promise enormous potential, as progress is made into stabilizing nanopore structures, enhancing chemistries, and improving data collection and bioinformatic analysis. This review offers a new perspective on current biomolecule sensing techniques, based on various types of nanopores, challenges, and approaches toward implementation in clinical settings.

Zinc finger protein‑like 1 is a novel neuroendocrine biomarker for prostate cancer

Prostate‑derived calcitonin (CT) and its receptor induce tumorigenicity and increase metastatic potential of prostate cancer (PC). CT‑inducible genes in human prostate were identified by subtraction hybridization. Among these genes, zinc finger protein like 1 (ZFPL1) protein was interesting since it was abundantly expressed in malignant prostates but was almost absent in benign prostates. ZFPL1 expression was upregulated by CT and androgens, and ZFPL1 protein was secreted by prostate tumor cells through exosomal secretion. Serum levels of ZFPL1 in cancer patients were at least 4‑fold higher than those in the sera of cancer‑free individuals. Cell biology of ZFPL1 suggests its localization in Golgi bodies and exosomes, and its colocalization with chromogranin A and CD44. These results suggested that ZFPL1 is secreted by tumor cells of neuroendocrine (NE)/stem cell phenotype. The knockdown of endogenous ZFPL1 in (PC) cells led to a remarkable decrease in cell proliferation, and invasion while increasing their apoptosis. As expected, the overexpression of ZFPL1 in prostate cells had an opposite effect on these functions. The knockdown of ZFPL1 in PC cells also decreased Akt phosphorylation, suggesting the actions of ZFPL1 may be mediated through the PI3K‑Akt pathway. Moreover, the present results revealed that ZFPL1 is released by tumors cells of NE or androgen‑independent phenotype and its serum levels are significantly higher in cancer patients, suggesting that it may serve as a blood‑based non‑invasive biomarker of aggressive PC.

Modified ELISA for Ultrasensitive Diagnosis

An enzyme-linked immunosorbent assay (ELISA) can be used for quantitative measurement of proteins, and improving the detection sensitivity to the ultrasensitive level would facilitate the diagnosis of various diseases. In the present review article, we first define the term 'ultrasensitive'. We follow this with a survey and discussion of the current literature regarding modified ELISA methods with ultrasensitive detection and their application for diagnosis. Finally, we introduce our own newly devised system for ultrasensitive ELISA combined with thionicotinamide adenine dinucleotide cycling and its application for the diagnosis of infectious diseases and lifestyle-related diseases. The aim of the present article is to expand the application of ultrasensitive ELISAs in the medical and biological fields.

On chip detection of glial cell-derived neurotrophic factor secreted from dopaminergic cells under magnetic stimulation

Glial cell-derived neurotrophic factor (GDNF) is a small protein potently promoting the survival of dopaminergic and motor neurons. GDNF can be secreted from different types of cells including the dopaminergic neural cell line, N27. N27 cells, a rat dopaminergic neural cell line, is regarded as a suitable in vitro model for Parkinson's disease (PD) research. For PD treatment, transcranial magnetic stimulation (TMS), a noninvasive therapeutic method, showed beneficial clinical effects, but the mechanism for its benefit is not understood. Because GDNF is a potent neurotrophic factor, it is of great value to evaluate if GDNF secretion from N27 cells can be affected by magnetic stimulation (MS). However, the current methods for detecting GDNF are time-consuming and expensive. In this paper we outline the detection of GDNF secretion from N27 cells by ultrasensitive nanopore thin film sensors (nanosensor) for the first time. As low as 2 pg/mL GDNF can be readily detected by the nanosensor. Furthermore, we show that MS can promote GDNF secretion from N27 cells. Specifically, the GDNF concentration in N27 cell-conditioned media under MS treatment shows statistically significant increase up to 2-fold after 5 days in vitro in comparison with the control. This nanosensor along with the in vitro PD model N27 cells provides a low-cost, easy-to-use, sensitive approach for studying potential cell biological mechanisms of the clinical benefits of MS on PD.

Evaluation of E2F3 and survivin expression in peripheral blood as potential diagnostic markers of prostate cancer

Background

Prostate cancer (PC) incidence has risen globally. As there are no current independent biomarkers with high diagnostic efficiency to detect PC, this study was performed to investigate the relative gene expression levels of E2F3 and survivin in the whole blood of PC, benign prostate hyperplasia (BPH), and normal control individuals and to explore their diagnostic value.

Material and methods

Participants of the study were divided into three groups; normal control group (n=25), BPH patients (n=25), and PC patients (n=75). The E2F3 and survivin gene expression levels were assessed using real-time qPCR in addition to the measurement of free and total levels of prostate-specific antigen (PSA) using electrochemiluminescence assays.

Results

Survivin relative gene expression was over-expressed in PC and BPH patients compared to the normal control group, whereas, E2F3 did not differ significantly among the studied groups. Compared to PSA, E2F3 and survivin mRNA expression levels had lower diagnostic efficacy to differentiate PC from normal and BPH individuals with an area under curve (AUC) of 0.471 and 0.727, respectively. Further, survivin expression level was associated with increased the risk of PC.

Conclusion

Survivin and E2F3 relative expression levels in peripheral blood had low diagnostic performance to detect PC and individuals with high survivin expression levels may have higher risk to develop PC.

Nanopore blockade sensors for ultrasensitive detection of proteins in complex biological samples

Nanopore sensors detect individual species passing through a nanoscale pore. This experimental paradigm suffers from long analysis times at low analyte concentration and non-specific signals in complex media. These limit effectiveness of nanopore sensors for quantitative analysis. Here, we address these challenges using antibody-modified magnetic nanoparticles ((anti-PSA)-MNPs) that diffuse at zero magnetic field to capture the analyte, prostate-specific antigen (PSA). The (anti-PSA)-MNPs are magnetically driven to block an array of nanopores rather than translocate through the nanopore. Specificity is obtained by modifying nanopores with anti-PSA antibodies such that PSA molecules captured by (anti-PSA)-MNPs form an immunosandwich in the nanopore. Reversing the magnetic field removes (anti-PSA)-MNPs that have not captured PSA, limiting non-specific effects. The combined features allow detecting PSA in whole blood with a 0.8 fM detection limit. Our ‘magnetic nanoparticle, nanopore blockade’ concept points towards a strategy to improving nanopore biosensors for quantitative analysis of various protein and nucleic acid species.

Nanopore sensors have long analysis times when analytes are at low concentration and non-specific signals in complex media. Here the authors use antibody-modified magnetic nanoparticles to detect prostate-specific antigen at sub-femtomolar concentrations in blood.

Hyaluronate-Functionalized Graphene for Label-Free Electrochemical Cytosensing

Electrochemical sensors for early tumor cell detection are currently an important area of research, as this special region directly improves the efficiency of cancer treatment. Functional graphene is a promising alternative for selective recognition and capture of target cancer cells. In our work, an effective cytosensor of hyaluronate-functionalized graphene (HG) was prepared through chemical reduction of graphene oxide. The as-prepared HG nanostructures were characterized with Fourier transform infrared spectroscopy and transmission electron microscopy coupled with cyclic voltammograms and electrochemical impedance spectroscopy, respectively. The self-assembly of HG with ethylene diamine, followed by sodium hyaluronate, enabled the fabrication of a label-free electrochemical impedance spectroscopy cytosensor with high stability and biocompatibility. Finally, the proposed cytosensor exhibited satisfying electrochemical behavior and cell-capture capacity for human colorectal cancer cells HCT-116, and also displayed a wide linear range, from 5.0 × 10² cells∙mL-1 to 5.0 × 10⁶ cells∙mL-1, and a low detection limit of 100 cells∙mL-1 (S/N = 3) for quantification. This work paves the way for graphene applications in electrochemical cytosensing and other bioassays.

An aptamer nanopore-enabled microsensor for detection of theophylline

This paper reports an aptamer-based nanopore thin film sensor for detecting theophylline in the buffer solution and complex fluids including plant extracts and serum samples. Compared to antibody-based detection, aptamer-based detection offers many advantages such as low cost and high stability at elevated temperatures. Experiments found that this type of sensor can readily detect theophylline at a concentration as low as 0.05µM, which is much lower than the detection limit of current lab-based equipment such as liquid chromatography (LC). Experiments also found that the aptamer-based sensor has good specificity, selectivity, and reasonable reusability with a significantly improved dynamic detection range. By using the same nanopore thin film sensors as the reference sensors to further mitigate the non-specific binding effect, the theophylline in plant extracts and serum has been detected. Only a small amount (~1μL) of plant extracts or serum samples is required to measure theophylline. Its low cost and ease-of-operation make this type of sensor suitable for point-of-care application to monitor the theophylline level of patients in real time.

Nanomaterial-based biosensors for detection of prostate specific antigen

Screening serum for the presence of prostate specific antigen (PSA) belongs to the most common approach for the detection of prostate cancer. This review (with 156 refs.) addresses recent developments in PSA detection based on the use of various kinds of nanomaterials. It starts with an introduction into the field, the significance of testing for PSA, and on current limitations. A first main section treats electrochemical biosensors for PSA, with subsections on methods based on the use of gold electrodes, graphene or graphene-oxide, carbon nanotubes, hybrid nanoparticles, and other types of nanoparticles. It also covers electrochemical methods based on the enzyme-like activity of PSA, on DNA-, aptamer- and biofuel cell-based methods, and on the detection of PSA via its glycan part. The next main section covers optical biosensors, with subsections on methods making use of surface plasmon resonance (SPR), localized SPR and plasmonic ELISA-like schemes. This is followed by subsections on methods based on the use of fiber optics, fluorescence, chemiluminescence, Raman scattering and SERS, electrochemiluminescence and cantilever-based methods. The most sensitive biosensors are the electrochemical ones, with lowest limits of detection (down to attomolar concentrations), followed by mass cantilever sensing and electrochemilumenescent strategies. Optical biosensors show lower performance, but are still more sensitive compared to standard ELISA. The most commonly applied nanomaterials are metal and carbon-based ones and their hybrid composites used for different amplification strategies. The most attractive sensing schemes are summarized in a Table. The review ends with a section on conclusions and perspectives.

Tunable Magneto-Optical Kerr Effects of Nanoporous Thin Films

Magnetoplasmonics, combining magnetic and plasmonic functions, has attracted increasing attention owing to its unique magnetic and optical properties in various nano-architectures. In this work, Ag, CoFeB and ITO layers are fabricated on anodic aluminum oxide (AAO) porous films to form hybrid multi-layered nanoporous thin films by magnetron sputtering deposition process. The designed nanostructure supports localized surface plasmon resonance (LSPR) and tunable magneto-optical (MO) activity, namely, the sign inversion, which can be controlled by AAO porous film geometry (pore diameter and inter-pore spacing) flexibly. The physical mechanism of this special MO phenomena is further analyzed and discussed by the correlation of Kerr rotation and electronic oscillations controlled by the surface plasmon resonance that is related to the nanoporous structure.