A New Eye Dual-readout Method for MiRNA Detection based on Dissolution of Gold nanoparticles via LSPR by CdTe QDs Photoinduction

Nanoplasmonic biosensors for precision medicine

Nanoplasmonic biosensors have a huge boost for precision medicine, which allows doctors to better understand diseases at the molecular level and to improve the earlier diagnosis and develop treatment programs. Unlike traditional biosensors, nanoplasmonic biosensors meet the global health industry's need for low-cost, rapid and portable aspects, while offering multiplexing, high sensitivity and real-time detection. In this review, we describe the common detection schemes used based on localized plasmon resonance (LSPR) and highlight three sensing classes based on LSPR. Then, we present the recent applications of nanoplasmonic in other sensing methods such as isothermal amplification, CRISPR/Cas systems, lab on a chip and enzyme-linked immunosorbent assay. The advantages of nanoplasmonic-based integrated sensing for multiple methods are discussed. Finally, we review the current applications of nanoplasmonic biosensors in precision medicine, such as DNA mutation, vaccine evaluation and drug delivery. The obstacles faced by nanoplasmonic biosensors and the current countermeasures are discussed.

Gold Nanoparticles as a Biosensor for Cancer Biomarker Determination

Molecular biology applications based on gold nanotechnology have revolutionary impacts, especially in diagnosing and treating molecular and cellular levels. The combination of plasmonic resonance, biochemistry, and optoelectronic engineering has increased the detection of molecules and the possibility of atoms. These advantages have brought medical research to the cellular level for application potential. Many research groups are working towards this. The superior analytical properties of gold nanoparticles can not only be used as an effective drug screening instrument for gene sequencing in new drug development but also as an essential tool for detecting physiological functions, such as blood glucose, antigen-antibody analysis, etc. The review introduces the principles of biomedical sensing systems, the principles of nanomaterial analysis applied to biomedicine at home and abroad, and the chemical surface modification of various gold nanoparticles.

Formation of miRNA Nanoprobes-Conjugation Approaches Leading to the Functionalization

Recently, microRNAs (miRNA) captured the interest as novel diagnostic and prognostic biomarkers, with their potential for early indication of numerous pathologies. Since miRNA is a short, non-coding RNA sequence, the sensitivity and selectivity of their detection remain a cornerstone of scientific research. As such, methods based on nanomaterials have emerged in hopes of developing fast and facile approaches. At the core of the detection method based on nanotechnology lie nanoprobes and other functionalized nanomaterials. Since miRNA sensing and detection are generally rooted in the capture of target miRNA with the complementary sequence of oligonucleotides, the sequence needs to be attached to the nanomaterial with a specific conjugation strategy. As each nanomaterial has its unique properties, and each conjugation approach presents its drawbacks and advantages, this review offers a condensed overview of the conjugation approaches in nanomaterial-based miRNA sensing. Starting with a brief recapitulation of specific properties and characteristics of nanomaterials that can be used as a substrate, the focus is then centered on covalent and non-covalent bonding chemistry, leading to the functionalization of the nanomaterials, which are the most commonly used in miRNA sensing methods.

Exploitation of N-Gene of SARS-CoV-2 to Develop a New Rapid Assay by ASOs@AuNPs

A naked-eye (equipment-free), label-free (cost-effective), and RNA extraction-free (to speed up) method for SARS-CoV-2 (as a case study of RNA viruses) detection is developed. Here, the DNA is being used as a template for in situ formation of anisotropic gold nanoparticles (AuNPs) without any chemical modification or DNA labeling. In this study, synthesized AuNPs for the direct detection of N-gene (nucleocapsid phosphoprotein) of SARS-CoV-2 are exploited. To this aim, antisense oligonucleotides (ASOs) with an extra poly guanine tail (G12) were designed. Thus, in the presence of its viral target RNA gene and ASOs@AuNPs-RNA hybridization, there was a red shift in its localized surface plasmon resonance (LSPR), and the intensity of the LSPR peak at 690 nm of throat swab samples was compared to the threshold cycle (Ct) of a reverse-transcriptase real-time polymerase chain reaction (RT-qPCR) (as a gold standard). Results suggested that the plasmonic biosensor can detect a very low amount of SARS-CoV-2 with a detection limit close to RT-qPCR. Simplicity of the new conjugation method with hybridization and annealing without amplification and denaturation steps enabled it to perform in a microfluidic paper-based analytical device.

Building Polyvalent DNA-Functionalized Anisotropic AuNPs Using Poly-Guanine-mediated In-Situ Synthesis For LSPR-Based Assays: Case Study on OncomiR-155

DNA functionalized gold nanoparticles (DNA-AuNPs) hold great promise for numerous biomedical applications, especially the building of well-defined nanosystems. Previously reported methods for the preparation of DNA-AuNPs all rely on the use of DNA bearing free thiol or disulfide groups at their 3'/5' ends. But here we report a novel polyvalent DNA-AuNPs conjugation approach by in-situ fast synthesis of AuNPs at the polyguanine (G₁₂ ) strands. As confirmed by both TEM images and gel electrophoresis analysis, many poly G strand can form an individual anisotropic AuNP and so each AuNP functionalized with a dense layer of DNA, resulting in the formation of polyvalent (p)DNA-AuNPs. The general applicability of this novel approach was further verified in hybridization test and UV-Vis spectroscopy results show that pDNA-AuNPs conjugation is more attractive in biomedical diagnosis and specific sequence detection like microRNA-155 by using an extra-strand poly G with "sticky end" that are complementary to the target sequence.

A fluorescent microarray platform based on catalytic hairpin assembly for MicroRNAs detection

The DNA microarray has distinctive advantages of high-throughput and less complicated operations, but tends to have a relatively low sensitivity. Catalytic hairpin assembly (CHA) is one of the most promising enzyme-free, isothermal DNA circuit for high efficient signal amplification. Here, a microarray-based catalytic hairpin assembly (mi-CHA) biosensing method has been developed to detect various miRNAs in a single test simultaneously. The target miRNA can trigger conformational transformations of hairpin-structured DNA probes on the chip surface and lead to the specific signal amplification. A significant advantage of this approach is that each duplex produced by the solid-phase CHA will be immobilized on the certain location of the chip and release fluorescent signal via the universal domain, eliminating the requirement of different fluorophores. This method has manifested a high detection sensitivity of human cancer-associated miRNAs (miR-21 and miR-155) down to 1.33 fM and promised a high specificity to distinguish single-base mismatches. Furthermore, the practicability of this method was demonstrated by analyzing target miRNAs in human serum and cancer cells. The experimental results suggest that the proposed method has high-throughput analytical potential and could be applied to many other clinical diagnosis.

Nanotechnology in emerging liquid biopsy applications

Liquid biopsy is considered as the most attractive alternative to traditional tissue biopsies. The major advantages of this approach lie in the non-invasive procedure, the rapidness of sample collection and the potential for early cancer diagnosis and real-time monitoring of the disease and the treatment response. Nanotechnology has dynamically emerged in a wide range of applications in the field of liquid biopsy. The benefits of using nanomaterials for biosensing include high sensitivity and detectability, simplicity in many cases, rapid analysis, the low cost of the analysis and the potential for portability and personalized medicine. The present paper reports on the nanomaterial-based methods and biosensors that have been developed for liquid biopsy applications. Most of the nanomaterials used exhibit great analytical performance; moreover, extremely low limits of detection have been achieved for all studied targets. This review will provide scientists with a comprehensive overview of all the nanomaterials and techniques that have been developed for liquid biopsy applications. A comparison of the developed methods in terms of detectability, dynamic range, time-length of the analysis and multiplicity, is also provided.

Photonic technologies for liquid biopsies: recent advances and open research challenges

The recent development of sophisticated techniques capable of detecting extremely low concentrations of circulating tumor biomarkers in accessible body fluids, such as blood or urine, could contribute to a paradigm shift in cancer diagnosis and treatment. By applying such techniques, clinicians can carry out liquid biopsies, providing information on tumor presence, evolution, and response to therapy. The implementation of biosensing platforms for liquid biopsies is particularly complex because this application domain demands high selectivity/specificity and challenging limit-of-detection (LoD) values. The interest in photonics as an enabling technology for liquid biopsies is growing owing to the well-known advantages of photonic biosensors over competing technologies in terms of compactness, immunity to external disturbance, and ultra-high spatial resolution. Some encouraging experimental results in the field of photonic devices and systems for liquid biopsy have already been achieved by using fluorescent labels and label-free techniques and by exploiting super-resolution microscopy, surface plasmon resonance, surface-enhanced Raman scattering, and whispering gallery mode resonators. This paper critically reviews the current state-of-the-art, starting from the requirements imposed by the detection of the most common circulating biomarkers. Open research challenges are considered together with competing technologies, and the most promising paths of improvement are discussed for future applications.

Role of miR-155 in pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a non-infectious, non-specific intestinal inflammatory disease, and its incidence is increasing year by year. A better understanding of the pathogenesis of IBD can help to find more suitable treatment methods for this disease. Recently, a large number of studies have shown that miR-155 plays an important role in the pathogenesis of IBD. It can regulate TH17 differentiation through the Jarid2/notch1 signaling pathway and by regulating type 2 macrophage differentiation. It also regulates T-regulatory cells by inhibiting cytotoxic T lymphocyte-associated antigen-4; intestinal myelofibrosis through suppressor of cytokine signaling 1; and DNA double-strand break deposition to affect intestinal inflammation. This article reviews the immune mechanism of action of miR-155 in IBD.