Disposal Immunosensor for Sensitive Electrochemical Detection of Prostate-Specific Antigen Based on Amino-Rich Nanochannels Array-Modified Patterned Indium Tin Oxide Electrode

Sensitive detection of prostate-specific antigens (PSA) in serum is essential for the prevention and early treatment of prostate cancer. Simple and disposable electrochemical immunosensors are highly desirable for screening and mobile detection of PSAs in high-risk populations. Here, an electrochemical immunosensor was constructed based on amino-rich nanochannels array-modified patterned, inexpensive, and disposable indium tin oxide (ITO) electrodes, which can be employed for the sensitive detection of PSA. Using an amino-group-containing precursor, a vertically ordered mesoporous silica nanochannel film (VMSF) containing amino groups (NH2-VMSF) was rapidly grown on ITO. When NH2-VMSF contained template surfactant micelle (SM), the outer surface of NH2-VMSF was directionally modified by aldehyde groups, which enabled further covalent immobilization of the recognitive antibody to prepare the immuno-recognitive interface. Owing to the charge-based selective permeability, NH2-VMSF can electrostatically adsorb negatively charged redox probes in solution (Fe(CN)63−/4−). The electrochemical detection of PSA is realized based on the mechanism that the antigen–antibody complex can reduce the diffusion of redox probes in solution to the underlying electrode, leading to the decrease in electrochemical signal. The constructed immunosensor can achieve sensitive detection of PSA in the range from 10 pg/mL to 1 μg/mL with a limit of detection (LOD) of 8.1 pg/mL. Sensitive detection of PSA in human serum was also achieved. The proposed disposable immunosensor based on cheap electrode and nanochannel array is expected to provide a new idea for developing a universal immunosensing platform for sensitive detection of tumor markers

Disposable Amperometric Label-Free Immunosensor on Chitosan–Graphene-Modified Patterned ITO Electrodes for Prostate Specific Antigen

A facile and highly sensitive determination of prostate-specific antigen (PSA) is of great significance for the early diagnosis, monitoring and prognosis of prostate cancer. In this work, a disposable and label-free electrochemical immunosensing platform was demonstrated based on chitosan–graphene-modified indium tin oxide (ITO) electrode, which enables sensitive amperometric determination of PSA. Chitosan (CS) modified reduced graphene oxide (rGO) nanocomposite (CS–rGO) was easily synthesized by the chemical reduction of graphene oxide (GO) using CS as a dispersant and biofunctionalizing agent. When CS–rGO was modified on the patterned ITO, CS offered high biocompatibility and reactive groups for the immobilization of recognition antibodies and rGO acted as a transduction element and enhancer to improve the electronic conductivity and stability of the CS–rGO composite film. The affinity-based biosensing interface was constructed by covalent immobilization of a specific polyclonal anti-PSA antibody (Ab) on the amino-enriched electrode surface via a facile glutaraldehyde (GA) cross-linking method, which was followed by the use of bovine serum albumin to block the non-specific sites. The immunosensor allowed the detection of PSA in a wide range from 1 to 5 ng mL−1 with a low limit of detection of 0.8 pg mL−1. This sensor also exhibited high selectivity, reproducibility, and good storage stability. The application of the prepared immunosensor was successfully validated by measuring PSA in spiked human serum samples

Synchronization Analysis of Fractional-Order Neural Networks With Adaptive Intermittent-Active Control

This paper concentrates on the study of adaptive control for the synchronization of fractional-order neural networks. Instead of classical adaptive control updating method, an intermittent-active updating strategy is proposed to adaptively tune the control gain in a fractional-order fashion. Moreover, quantization is brought into the control design to take into account the restricted bandwidth in signal transmission. Note that the suggested controller is basic yet effective in terms of the fractional-order system. The main theorem is established with the method of reduction to absurdity as well as Lyapunov stability theorem. Finally, simulation calculation is conducted to validate the effectiveness of our proposed method

Structural and Functional Characteristics of Soil Fungal Communities near Decomposing Moso Bamboo Stumps

Background and Objectives: Fungi degrade lignin and other fibers, thus playing an essential role in the decomposition of Phyllostachys edulis (Carrière) J.Houz. (Moso bamboo) stumps. Herein, we characterized key soil fungal communities near different levels of decomposing Moso bamboo stumps (mildly, moderately, and heavily decayed). Materials and Methods: High-throughput sequencing technology was used to analyze the soil fungal communities inside and outside of mild, moderate, and heavy decomposing Moso bamboo stumps. Results: We found nine phyla, 30 classes, 77 orders, 149 families, and 247 genera of soil fungi near the bamboo stumps. Soil fungi OTUs and diversity and richness indices were lower outside than inside the stumps, and decreased with increasing degrees of decay. Inside the bamboo stumps, Soil fungi OTUs and diversity and richness indices were the highest and lowest in moderate and heavy decay bamboo stumps, respectively. Ascomycota dominated inside (from 81% to 46%) and outside (from 69% to 49%) the stumps, and their relative abundance gradually decreased with decomposition, whereas that of Basidiomycota increased outside the stumps (from 17% to 49%). Two-way ANOVA showed that the interaction between the two factors of occurring inside and outside the bamboo stumps and the degree of decay, significantly affected Chytridiomycota and Penicillium (p p < 0.05). The abundance of different genera was significantly correlated with saprotrophic functional groups. Conclusion: Changes in the structure and functional groups of soil fungal communities may play an important role during different levels of decomposition of Moso bamboo stumps. This study provides a scientific basis for screening functional fungal strains that promote the decomposition of Moso bamboo stumps

Transdermal Delivery of Anti-Obesity Compounds to Subcutaneous Adipose Tissue with Polymeric Microneedle Patches

Excess white adipose tissue (WAT), or obesity, is the leading cause of many diseases. Combating obesity is, however, challenging due to the fact that laboratory-proven anti-obesity compounds lose effectiveness or/and cause severe side-effects while being delivered via conventional routes. Here, a new strategy is reported using disposable transdermal patches equipped with detachable polymeric microneedle (MN) arrays for painless and bloodless drug delivery to subcutaneous WAT. In contrast to the current methods to reduce energy intake, MN-patches are used to deliver anti-obesity compounds to increase energy expenditure by transforming calorie-storing white fat into calorie-burning brown fat. Specifically, prominent WAT browning and reduction effects are demonstrated by β3-adrenoceptor agonist and thyroid hormone T3 transdermally delivered from rapidly dissolving MNs on mice. Furthermore, using a diet-induced obese mouse model, it is shown that β3-adrenoceptor agonist released by slowly dissolving MNs can effectively promote WAT browning and suppress gaining of body fat and weight, without the need of daily administration. Such an MN approach can achieve a much lower effective dose as compared to systemic administration and enables long-term home-based treatment.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)NMRC (Natl Medical Research Council, S’pore)Accepted versio