Advances in microneedles for transdermal diagnostics and sensing applications.

Microneedles, the miniaturized needles, which can pierce the skin with minimal invasiveness open up new possibilities for constructing personalized Point-of-Care (POC) diagnostic platforms. Recent advances in microneedle-based POC diagnostic systems, especially their successful implementation with wearable technologies, enable biochemical detection and physiological recordings in a user-friendly manner. This review presents an overview of the current advances in microneedle-based sensor devices, with emphasis on the biological basis of transdermal sensing, fabrication, and application of different types of microneedles, and a summary of microneedle devices based on various sensing strategies. It concludes with the challenges and future prospects of this swiftly growing field. The aim is to present a critical and thorough analysis of the state-of-the-art development of transdermal diagnostics and sensing devices based on microneedles, and to bridge the gap between microneedle technology and pragmatic applications.

Diagnostic value of Status Epilepticus Severity Score for survival conditions of patients with status epilepticus: A PRISMA-compliant systematic review and meta-analysis.

OBJECTIVE: In recent years, the Status Epilepticus Severity Score (STESS) has been widely used to predict survival conditions of patients with status epilepticus (SE). However, the diagnostic value of STESS has not yet been evaluated. We therefore performed this meta-analysis to assess the overall diagnostic accuracy of STESS for predicting survival condition of patients with SE. METHODS: Systemic searches for relevant published studies were conducted in EMBASE, PubMed, Web of Science, and Cochrange databases up to July 2, 2017. Quality Assessment of Diagnostic Accuracy Studies (QUADAS) was used to evaluate the quality of included studies. All statistical analyses were performed using Stata12.0 and Meta-DiSc software. RESULTS: A total of 11 studies including 12 observations with 1356 patients were included in this meta-analysis. Summary estimates of the diagnostic value of STESS for survival condition of patients with SE were listed as follows: sensitivity, 0.81 (95% confidence intervals (CI): 0.76-0.85); specificity, 0.53 (95% CI: 0.50-0.56); positive likelihood ratio (PLR), 1.86 (95% CI: 1.57-2.21); negative likelihood ratio (NLR), 0.38 (95% CI: 0.30-0.48); diagnostic odds ratio (DOR), 5.24 (95% CI: 3.49-7.87); and area under the curve (AUC), 0.81. Metaregression analysis showed that ethnicity, study design, publish year, and sample size did not significantly influence the diagnostic performance statistically (all P>0.05). CONCLUSIONS: The STESS is a promising candidate for predicting survival condition of patients with SE. However, the potential tool should be validated in well-designed studies with larger sample sizes.

Determination of the activity of telomerase in cancer cells by using BSA-protected gold nanoclusters as a fluorescent probe.

Gold nanoclusters (AuNCs) protected with a bovine serum albumin (BSA) coating are known to emit red fluorescence (peaking at 650 nm) on photoexcitation with ultraviolet light (365 nm). On addition of Cu(II) ions, fluorescence is quenched because Cu(II) complexes certain amino acid units in the BSA chain. Fluorescence is, however, restored if pyrophosphate (PPi) is added because it will chelate Cu(II) and remove it from the BSA coating on the AuNCs. Because PPi is involved in the function of telomerase, the BSA@AuNCs loaded with Cu(II) can act as a fluorescent probe for determination of the activity of telomerase. A fluorescent assay was worked out for telomerase that is highly sensitive and has a wide linear range (10 nU to 10 fM per mL). The fluorescent probe was applied to the determination of telomerase activity in cervix carcinoma cells via imaging. It is shown that tumor cells can be well distinguished from normal cells by monitoring the differences in intracellular telomerase activity. Graphical abstract Gold nanoclusters (AuNCs) protected by bovine serum albumin (BSA) and displaying red photoluminescence were prepared as fluorescent probe for the determination of telomerase activity and used for imaging of cervix carcinoma (HeLa) cells.

Sensitive determination of Hg(II) based on a hybridization chain recycling amplification reaction and surface-enhanced Raman scattering on gold nanoparticles.

A method was developed for the determination of mercuric ion Hg(II). It is based on hybridization chain reaction (HCR) and surface-enhanced Raman scattering (SERS). Raman signal DNA and streptavidin were self-assembled on gold nanoparticles as a novel signal nanoprobe (AuNP-sDNA). A thymine-mercury(II)-thymine structure was immobilized on magnetic beads (MBs). The HCR makes use of two hairpin probes that are initiated by the trigger DNA to form a stable nicked dsDNA structure (MB-TS-hDNAs). A large number of the binding sites is provided to connect the signal nanoprobe. The stable sandwich structure (MB-TS-hDNA/AuNP-sDNA) was isolated by applying a magnetic field and used in the amplification step. In this way, Hg(II) can be determined sensitively after multiple signal amplification. The SERS signal, measured at 1499 cm-1, increases linearly in the 0.1 pM to 10 nM Hg(II) concentration range, and the limit of detection is 0.08 pM (at an S/N ratio of 3). The method was applied to the detection of Hg(II) in spiked environment water samples, with recoveries ranging from 96 to 119%. Graphical abstract Schematic of a method based on the use of a stable T-Hg(II)-T structure and a self-assembled nanoprobe. It was applied to the trace Hg(II) detection based on hybridization chain reaction (HCR) and surface-enhanced Raman scattering (SERS).

Antifouling Electrochemiluminescence Biosensor Based on Bovine Serum Albumin Hydrogel for the Accurate Detection of p53 Gene in Human Serum.

To detect biomarkers in complex samples, it is fundamental to avoid the nonspecific adsorption of impurities to improve the selectivity of biosensors. In this study, a sensitive antifouling electrochemiluminescence biosensor was proposed based on bovine serum albumin (BSA)- and exonuclease III (Exo III)-mediated nucleic acid cycle signal amplification strategy. Ti3C2Tx-NH4, which has a large surface area and high metal conductivity, was crosslinked with BSA to improve the conductivity of the sensing interface, which shows antifouling performance excellently due to the electrical neutrality and good hydrophilicity of BSA hydrogel. The cyclic amplification strategy based on Exo III and DNA hybridization chain reaction significantly amplified the electrochemiluminescence signal and improved the sensitivity of p53 gene detection. The linear range of the biosensor is 1 fM-1 nM with a detection limit of 0.26 fM. More importantly, the sensor showed excellent selectivity when it was used to detect the p53 gene in real samples, such as serum. Thus, this unique antifouling sensing interface is expected to construct various electrochemical biosensors in clinical diagnosis and biopathological analysis.

Alpha-aminoisobutyric acid incorporated peptides for the construction of electrochemical biosensors with high stability and low fouling in serum.

An effective strategy to construct low fouling electrochemical biosensors for assaying serum biomarkers was proposed based on specially designed α-aminoisobutyric acid (Aib) incorporated peptides. The Aib-peptides were designed to be of antifouling properties, and at the same to incorporate Aib residues in their interior to enhance the hydrolytic stability. In order to construct the electrochemical biosensor, two kinds of Aib-peptides labelled with biotin were modified on the electrode surface: One with cysteine terminal for easy attachment to the electrode modified with gold nanoparticles, the other with unique terminal peptide sequence for specific binding of immunoglobulin G (IgG), and they were connected through the streptavidin-biotin affinity system. Owing to the interposition of Aib residues, the peptides as well as the constructed biosensors showed excellent antifouling performances and enhanced stability against enzymatic degradation in serum. Furthermore, the IgG biosensor constructed with the Aib-peptides displayed a very low detection limit (29.5 pg mL-1) and a broad linear range (100 pg mL-1 - 10 µg mL-1), and it was able to assay IgG in clinical human sera with decent accuracy and reliability. This strategy provides a new path for the construction of stable antifouling biosensors based on functional peptides for practical biomarker assaying in real clinical samples.

An ultrasensitive biosensor for prostate specific antigen detection in complex serum based on functional signal amplifier and designed peptides with both antifouling and recognizing capabilities.

The development of biosensors capable of averting biofouling and detecting biomarkers in complex biological media remains a challenge. Herein, an ultralow fouling and highly sensitive biosensor based on specifically designed antifouling peptides and a signal amplification strategy was designed for prostate specific antigen (PSA) detection in human serum. A low fouling layer of poly(ethylene glycol) (PEG) doped the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was electrodeposited on the electrode surface, followed by the immobilization of streptavidin and further attachment of biotin-labelled peptides. The peptide was designed to include PSA specific recognition domain (HSSKLQK) and antifouling domain (PPPPEKEKEKE), and the terminal of the peptide was functionalized with -SH group. DNA functionalized gold nanorods (DNA/AuNRs) were then attached to the electrode, and methylene blue (MB) molecules were adsorbed to the DNA to form the signal amplifier. In the presence of PSA, the peptide was specifically cleaved and resulted in the loss of AuNRs together with DNA and MB, and thus significant decrease of the current signal. The biosensor exhibited a low limit of detection (LOD) of 0.035 pg mL-1 (S/N = 3), with a wide linear range from 0.10 pg mL-1 to 10.0 ng mL-1, and it was able to detect PSA in real human serum owing to the presence of the antifouling peptides, indicating great potential of the constructed biosensor for practical application.

Antifouling biosensors for reliable protein quantification in serum based on designed all-in-one branched peptides.

Antifouling electrochemical biosensors based on designed all-in-one branched peptides that combine anchoring, doping, antifouling and recognizing functions were constructed to support sensitive and reliable protein quantification in complex serum samples.

Overexpression of HOXC10 promotes glioblastoma cell progression to a poor prognosis via the PI3K/AKT signalling pathway.

OBJECTIVE: The HOX gene is expressed in neoplasias occurred in multiple tissues, such as the colon, lung and breast. However, the effects of the HOX gene on glioblastoma (GBM) remain poorly understood. We examined HOXC10 expression in GBM tissues and cells, analysed its effect on GBM prognosis, and finally assessed its possible underlying mechanisms in this study. METHODS: HOXC10 expression levels and its prognostic effects on GBM tissues were analysed based on The Cancer Genome Atlas (TCGA) and ONCOMINE database. Overall survival (OS) analysis was performed using the Kaplan-Meier method and log rank test. Then, the expression of HOXC10 was detected in four GBM cell lines using quantitative real-time reverse transcription-PCR (qRT-PCR). In addition, small interfering RNA (si-RNA) was utilised in the U87 cell line with the highest HOXC10 expression to facilitate subsequent in vitro cell experiment. Cell proliferation, migration and invasion were assessed using the Cell Counting Kit-8 (CCK-8) and colony formation assay, wound healing, Transwell assay, respectively in GBM U87 cell after HOXC10 knockdown. Key proteins related to the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) signalling pathway were measured by western blotting. RESULTS: HOXC10 expression was significantly increased in GBM tissues and cell lines, leading a poor OS in GBM patients. Knockdown of HOXC10 could inhibit the GBM U87 cells proliferation, migration and invasion, as well as decreased expression levels of key proteins in PI3K/AKT signalling pathway. CONCLUSION: HOXC10 was overexpressed in GBM tissues and cells, and associated with poor prognosis in GBM patients. Moreover, HOXC10 knockdown inhibited U87 cell proliferation, migration and invasion, which were potentially related to PI3K/AKT signalling pathway activation. Our findings revealed that HOXC10 represent a promising biological target for GBM treatment in the future.

Aptamer based strategy for cytosensing and evaluation of HER-3 on the surface of MCF-7 cells by using the signal amplification of nucleic acid-functionalized nanocrystals.

The electrochemical detection of cell lines of MCF-7 (human breast cancer) has been reported, using magnetic beads for the separation tool and high-affinity DNA aptamers for signal recognition. The high specificity was obtained by using the magnetic beads and aptamers, and the good sensitivity was realized with the signal amplification of DNA capped CdS or PbS nanocrystals. The ASV (anodic stripping voltammetry) technology was employed for the detection of cadmic cation and lead ions, for electrochemical assay of the amount of the target cells and biomarkers on the membrane of target cells, respectively. This electrochemical method could respond to as low as 100 cells mL(-1) of cancer cells with a linear calibration range from 1.0×10(2) to 1.0×10(6) cells mL(-1), showing very high sensitivity. Moreover, the amounts of HER-3 which were overexpressed on MCF-7 cells were calculated correspond to be 3.56×10(4) anti-HER-3 antibody molecules. In addition, the assay was able to differentiate between different types of target and control cells based on the aptamers and magnetic beads used in the assay, indicating the wide applicability of the assay for early and accurate diagnose of cancers.