Intermittent lysis on a single paper-based device to extract exosomal nucleic acid biomarkers from biological samples for downstream analysis.

As the role of exosomes in physiological and pathological processes has been properly perceived, harvesting them and their internal components is critical for subsequent applications. This study is a debut of intermittent lysis, which has been integrated into a simple and easy-to-operate procedure on a single paper-based device to extract exosomal nucleic acid biomarkers for downstream analysis. Exosomes from biological samples were captured by anti-CD63-modified papers before being intermittently lysed by high-temperature, short-time treatment with double-distilled water to release their internal components.

Comparing solution-gate and bottom-gate nanowire field-effect transistors on pH sensing with different salt concentrations and surface modifications.

Field-effect transistors (FETs) have been developed as pH sensors by using various device structures, fabrication technologies, and sensing film materials. Different transistor structures, like extended-gate (EG) FETs, floating-gate FET sensors, and dual-gate (DG) FETs, can enhance the sensor performance. In this article, we report the effects of using solution-gate and bottom-gate FET configurations on pH sensing and investigate the influence of different ionic concentrations of buffers in the measured signals.

Paper-Based Exosomal MicroRNA-21 Detection for Wound Monitoring: A Proof of Concept and Clinical Validation Trial Study.

Emerging evidence has shown that microRNAs play pivotal roles in wound healing. MicroRNA-21 (miR-21) was previously found to upregulate in order to fulfill an anti-inflammation role for wounds. Exosomal miRNAs have been identified and explored as essential markers for diagnostic medicine.

Paper/PMMA hybrid device with a microvalve-controlled design for exosome isolation and analysis.

This study proposes a paper/PMMA hybrid device designed to isolate exosomes and extract exosomal miRNA, followed by quantitative analysis. It aims to provide simplified and convenient sample preparation for potential point-of-care testing (POCT) processes. In contrast to previous work conducted by our research team, which focused on isolating exosomes and exosomal nucleic acids, this study introduces a novel approach by integrating paper and a PMMA mold with a microvalve controlled design.

Ultrasensitive Detection of Interleukin 6 by Using Silicon Nanowire Field-Effect Transistors.

Interleukin 6 (IL-6) has been regarded as a biomarker that can be applied as a predictor for the severity of COVID-19-infected patients. The IL-6 level also correlates well with respiratory dysfunction and mortality risk. In this work, three silanization approaches and two types of biorecognition elements were used on the silicon nanowire field-effect transistors (SiNW-FETs) to investigate and compare the sensing performance on the detection of IL-6.

Paper-Based Devices for Capturing Exosomes and Exosomal Nucleic Acids From Biological Samples.

Exosomes, nanovesicles derived from cells, contain a variety of biomolecules that can be considered biomarkers for disease diagnosis, including microRNAs (miRNAs). Given knowledge and demand, inexpensive, robust, and easy-to-use tools that are compatible with downstream nucleic acid detection should be developed to replace traditional methodologies for point-of-care testing (POCT) applications. This study deploys a paper-based extraction kit for exosome and exosomal miRNA analytical system with some quantifying methods to serve as an easy sample preparation for a possible POCT process.

Phosphate-Methylated Oligonucleotides as a Novel Primer for PCR and RT-PCR.

This chapter introduces neutralized DNA (nDNA) as a novel design for the primers of PCR and RT-PCR by methylating phosphate groups of some oligonucleotides in their structures. It starts with an introduction of the nDNA which possesses an electrically chimeric neutral backbone as well as the proposed standards in designing nDNA as a novel primer for PCR and RT-PCR , concluded from various experimental results presented afterward. The primary content comprises empirical data from PCR to compare nDNA and unmodified DNA as primers in terms of ability to distinguish and amplify mismatch templates, activities of polymerase enzymes, melting temperature of double-stranded sequences, and the trials and discussions on various modified positions of the nDNA primers.

Optimizing surface modification of silicon nanowire field-effect transistors by polyethylene glycol for MicroRNA detection.

MicroRNA (miRNA) sensing plays an essential role in the diagnosis of several diseases, especially cancers, for appropriate intervention and treatment. However, quantifying miRNA demands highly sensitive and selective assays which can distinguish analogous sequences with low abundance in bio-samples and determine wide range of concentrations. In this report, we present a novel technique satisfying all those requirements by modifying silicon nanowire field-effect transistors (SiNWFETs) with 2-component mixed self-assembled monolayers (mSAMs) of polyethylene glycol (PEG) at different ratios (silane-PEG-NH:silane-PEG-OH = 1:1, 1:3, and 1:5) and glutaraldehyde to immobilize DNA probes for miRNA-21 detection, a biomarker in several types of cancers.

Combination of Aptamer Amplifier and Antigen-Binding Fragment Probe as a Novel Strategy to Improve Detection Limit of Silicon Nanowire Field-Effect Transistor Immunosensors.

Detecting proteins at low concentrations in high-ionic-strength conditions by silicon nanowire field-effect transistors (SiNWFETs) is severely hindered due to the weakened signal, primarily caused by screening effects. In this study, aptamer as a signal amplifier, which has already been reported by our group, is integrated into SiNWFET immunosensors employing antigen-binding fragments (Fab) as the receptors to improve its detection limit for the first time. The Fab-SiNWFET immunosensors were developed by immobilizing Fab onto Si surfaces modified with either 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA) (Fab/APTES-SiNWFETs), or mixed self-assembled monolayers (mSAMs) of polyethylene glycol (PEG) and GA (Fab/PEG-SiNWFETs), to detect the rabbit IgG at different concentrations in a high-ionic-strength environment (150 mM Bis-Tris Propane) followed by incubation with R18, an aptamer which can specifically target rabbit IgG, for signal enhancement.

Predicting Future Prospects of Aptamers in Field-Effect Transistor Biosensors.

Aptamers, in sensing technology, are famous for their role as receptors in versatile applications due to their high specificity and selectivity to a wide range of targets including proteins, small molecules, oligonucleotides, metal ions, viruses, and cells. The outburst of field-effect transistors provides a label-free detection and ultra-sensitive technique with significantly improved results in terms of detection of substances. However, their combination in this field is challenged by several factors.

Field-Effect Transistor Biosensors for Biomedical Applications: Recent Advances and Future Prospects.

During recent years, field-effect transistor biosensors (Bio-FET) for biomedical applications have experienced a robust development with evolutions in FET characteristics as well as modification of bio-receptor structures. This review initially provides contemplation on this progress by briefly summarizing remarkable studies on two aforementioned aspects. The former includes fabricating unprecedented nanostructures and employing novel materials for FET transducers whereas the latter primarily synthesizes compact molecules as bio-probes (antibody fragments and aptamers).

Signal Enhancement of Silicon Nanowire Field-Effect Transistor Immunosensors by RNA Aptamer.

Silicon nanowire field-effect transistors (SiNW-FETs) have been demonstrated as a highly sensitive platform for label-free detection of a variety of biological and chemical entities. However, detecting signal from immunoassays by nano-FETs is severely hindered by the distribution of different charged groups of targeted entities, their binding orientation, and distances to the surface of the FET. Aptamers have been widely applied as a recognition element for plentiful biosensors because of small molecular sizes and moderate to high specific binding affinity with different types of molecules.