An ultrasensitive electrochemiluminescence sensor for the detection of HULC based on Au@Ag/GQDs as a signal indicator

Opportunities and challenges of using high-sensitivity nanobiosensors to detect long noncoding RNAs: A preliminary review

The two types ofncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), are responsible for several biological processes within cells, such as the immune responses, cell growth and invasion, and regulation of the cell cycle. Rapidly expanding class of ncRNAs, lncRNAsinteract with other molecules to form chromatin-remodeling complexes. These potential hallmarks of diseases contribute to transcriptional and post-transcriptional regulation of several genes, possibly via cross-talk with other RNAs. Aberrant expression of lncRNAshas drawn increasing attention to the pathophysiology of different diseases, includingcancer and cardiovasculardiseases. Unfortunately, circulating lncRNAs are presented in the bloodstream at very low levels, making sensitive detection difficult. Currently, there are few methods for detecting these ncRNAs from which quantitative real-time-polymerase chain reaction (qRT-PCR) is the most routinely used technique. These techniqueslack sensitivity for intracellular detection of lncRNAs. Moreover, they are tedious and require a large sample size. Currently, nanotechnology has taken over the diagnostic field because of the tunable properties and modification opportunities. Furthermore, these conventional techniques can be merged with nanotechnology to improve detection sensitivity.This review highlights some of the most recent findings on nanotechnology-based methods and possible obstacles intheir application for moreaccurate sensing of lncRNAs.

Antifouling lipid membrane coupled with silver nanoparticles for electrochemical detection of nucleic acids in biological fluids

Electrochemical method capable of detecting specific nucleic acids in complex fluid will undoubtedly advance the diagnosis of many kinds of diseases. Herein, by coupling lipid membrane with silver nanoparticles (AgNPs), we develop a new electrochemical method for sensitive and reliable detection of nucleic acids in biological fluids. The advantages of lipid membrane especially its excellent antifouling ability is employed to enhance the applicability of the method in complex environment; while the significant solid-state Ag/AgCl response of AgNPs is used to ensure the detection sensitivity of the method. The core of this method's workflow is the target-induced Y-shape structure formation, which results in the recruitment of AgNPs to the electrode surface, producing considerable electrochemical responses used for target nucleic acid detection. Taking highly upregulated in liver cancer (HULC), a liver cancer-related long non-coding RNA as a model target, the method exhibits high sensitivity, specificity, and reproducibility with a detection limit of 0.42 fM. Moreover, the method displays desirable usability in biological fluids such as serum, which will be of great potential in clinical diagnosis.

Dual-mode glucose nanosensor as an activatable theranostic platform for cancer cell recognition and cascades-enhanced synergetic therapy

Integration of disease diagnosis and therapy is crucial in precise medicine, while the "always on" mode often hinders its clinical applications. Herein, inspired by cascaded catalysis, an integrated dual-mode glucose nanosensor as an activable theranostic platform is developed, which is further exploited for cancer cell recognition and enhanced synergistic therapy of lymph cancer. This nanosensor is prepared through the in-situ growth of silver nanoparticles (AgNPs) with the synergetic reduction of tannic acid (TA) and graphene quantum dots (GQDs), which are further decorated with glucose oxidase (GOx). A cascaded catalytic reaction is triggered by glucose, in which GOx catalyzes the oxidation of glucose into gluconic acid and hydrogen peroxide (H₂O₂), and hydroxyl radical (•OH) is further produced with the catalysis of GQDs nanozyme with peroxidase-like activity, resulting in the degradation of AgNPs@GQDs-GOx with the release of Ag⁺. Accordingly, a "turn-off" colorimetric and "turn-on" fluorescence dual-mode glucose nanosensor is fabricated, which is readily applied for cancer cell recognition via fluorescence imaging based on the high glucose level in tumor microenvironment. Moreover, the degradation of AgNPs@GQDs-GOx in response to glucose facilitates the cascades-enhanced synergistic therapy of lymph cancer with the combination of starving-like therapy, metal ion therapy and TA-induce apoptosis. This study highlights a glucose-activated theranostic nanoplatform, which provides a great opportunity for cancer-related biosensing, bioimaging and biomedical applications.

Non-Coding RNA-Based Biosensors for Early Detection of Liver Cancer

Primary liver cancer is an aggressive, lethal malignancy that ranks as the fourth leading cause of cancer-related death worldwide. Its 5-year mortality rate is estimated to be more than 95%. This significant low survival rate is due to poor diagnosis, which can be referred to as the lack of sufficient and early-stage detection methods. Many liver cancer-associated non-coding RNAs (ncRNAs) have been extensively examined to serve as promising biomarkers for precise diagnostics, prognostics, and the evaluation of the therapeutic progress. For the simple, rapid, and selective ncRNA detection, various nanomaterial-enhanced biosensors have been developed based on electrochemical, optical, and electromechanical detection methods. This review presents ncRNAs as the potential biomarkers for the early-stage diagnosis of liver cancer. Moreover, a comprehensive overview of recent developments in nanobiosensors for liver cancer-related ncRNA detection is provided.

Recent advances in heteroatom-doped graphene quantum dots for sensing applications

Graphene quantum dots (GQDs) are carbon-based fluorescent nanomaterials having various applications due to attractive properties. But the low photoluminescence (PL) yield and monochromatic PL behavior of GQDs put limitations on their real-time applications. Therefore, heteroatom doping of GQDs is recognized as the best approach to modify the optical as well as electronic properties of GQDs by modifying their chemical composition and electronic structure. In this review, the new strategies for preparing the heteroatom (N, B, S, P) doped GQDs by using different precursors and methods are discussed in detail. The particle size, emission wavelength, PL emissive color, and quantum yield of recently developed heteroatom doped GQDs are reported in this article. The investigation of structure, crystalline nature, and composition of heteroatom doped GQDs by various characterization techniques such as high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) are also described. The recent progress on the impact of mono or co-doping of heteroatoms on PL behavior, and optical, electrochemiluminescence (ECL), and electrochemical properties of GQDs is also surveyed. Further, heteroatom doped GQDs with attractive properties used in sensing of various metal ions, biomolecules, small organic molecules, etc. by using various techniques with different limits of detection are also summarized. This review provides progressive trends in the development of heteroatom doped GQDs and their various applications.

Carbon Based Nanodots in Early Diagnosis of Cancer

Detection of cancer at an early stage is one of the principal factors associated with successful treatment outcome. However, current diagnostic methods are not capable of making sensitive and robust cancer diagnosis. Nanotechnology based products exhibit unique physical, optical and electrical properties that can be useful in diagnosis. These nanotech-enabled diagnostic representatives have proved to be generally more capable and consistent; as they selectively accumulated in the tumor site due to their miniscule size. This article rotates around the conventional imaging techniques, the use of carbon based nanodots viz Carbon Quantum Dots (CQDs), Graphene Quantum Dots (GQDs), Nanodiamonds, Fullerene, and Carbon Nanotubes that have been synthesized in recent years, along with the discovery of a wide range of biomarkers to identify cancer at early stage. Early detection of cancer using nanoconstructs is anticipated to be a distinct reality in the coming years.

Electrochemiluminescence Biosensors Using Screen-Printed Electrodes

Electrogenerated chemiluminescence (also called electrochemiluminescence (ECL)) has become a great focus of attention in different fields of analysis, mainly as a consequence of the potential remarkably high sensitivity and wide dynamic range. In the particular case of sensing applications, ECL biosensor unites the benefits of the high selectivity of biological recognition elements and the high sensitivity of ECL analysis methods. Hence, it is a powerful analytical device for sensitive detection of different analytes of interest in medical prognosis and diagnosis, food control and environment. These wide range of applications are increased by the introduction of screen-printed electrodes (SPEs). Disposable SPE-based biosensors cover the need to perform in-situ measurements with portable devices quickly and accurately. In this review, we sum up the latest biosensing applications and current progress on ECL bioanalysis combined with disposable SPEs in the field of bio affinity ECL sensors including immunosensors, DNA analysis and catalytic ECL sensors. Furthermore, the integration of nanomaterials with particular physical and chemical properties in the ECL biosensing systems has improved tremendously their sensitivity and overall performance, being one of the most appropriates research fields for the development of highly sensitive ECL biosensor devices.

Recent developments in electrochemiluminescence nanosensors for cancer diagnosis applications

In recent years, electrochemiluminescence (ECL) nanosensing systems have undergone rapid development and made significant progress in ultrasensitive analysis and cell imaging. Because of the unique advantages of high selectivity, ultra-sensitivity, and good reproducibility, ECL nanosensors can open new paths for cancer diagnosis. With the development of ECL nanosensors, high-throughput analysis, visual detection and spatially resolved ECL imaging of single cells are being realized. The innovations of ECL nanosensors consist of electrochemical excitation, coreactant catalysis, light radiation and luminescence signal amplification, which involve several fields such as nanotechnology, catalysis, optics, and electrochemistry. The developments of ECL instruments also relate to imaging technology. Herein, we review the construction modes, sensing strategies and cancer diagnosis applications of ECL nanosenors. Firstly, the nano-components of the ECL sensing system are discussed. The construction and signal amplification methods of the nanosensing system are emphasized. Secondly, the high-efficiency cancer identification strategies are presented, including protein tumor marker detection, nucleic acid assay, cancer cell identification and exosome detection. The recent advances in representative examples of ECL nanosenors in cancer diagnosis are highlighted, including high-throughput ECL analysis, in situ assay, visual ECL detection, single-cell imaging diagnosis, and so on. Finally, the challenges are featured based on the recent development of the ECL nanosensing system in the clinical diagnosis. The ECL nanosensors provide effective and reliable analytical methods and open new paths for cancer diagnosis. It is noteworthy that the prospects of the ECL nanosensing system in clinical diagnosis are instructive to the developments of other nanosensor research.

Applications of Graphene Quantum Dots in Biomedical Sensors

Due to the proliferative cancer rates, cardiovascular diseases, neurodegenerative disorders, autoimmune diseases and a plethora of infections across the globe, it is essential to introduce strategies that can rapidly and specifically detect the ultralow concentrations of relevant biomarkers, pathogens, toxins and pharmaceuticals in biological matrices. Considering these pathophysiologies, various research works have become necessary to fabricate biosensors for their early diagnosis and treatment, using nanomaterials like quantum dots (QDs). These nanomaterials effectively ameliorate the sensor performance with respect to their reproducibility, selectivity as well as sensitivity. In particular, graphene quantum dots (GQDs), which are ideally graphene fragments of nanometer size, constitute discrete features such as acting as attractive fluorophores and excellent electro-catalysts owing to their photo-stability, water-solubility, biocompatibility, non-toxicity and lucrativeness that make them favorable candidates for a wide range of novel biomedical applications. Herein, we reviewed about 300 biomedical studies reported over the last five years which entail the state of art as well as some pioneering ideas with respect to the prominent role of GQDs, especially in the development of optical, electrochemical and photoelectrochemical biosensors. Additionally, we outline the ideal properties of GQDs, their eclectic methods of synthesis, and the general principle behind several biosensing techniques.

PAMAM/polyhedral nanogold-modified probes with DNAase catalysis for the amperometric electrochemical detection of metastasis-associated lung adenocarcinoma transcript 1

Abstract

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), a long non coding RNA (lncRNA) present in serum, is an important biomarker for detecting hepatocellular carcinoma (HCC). However, there are some shortcomings in current detection methods. So developing other novel MALAT1 detection methods is necessary. Electrochemical biosensors using different types of nanomaterials with various advantages may provide a suitable method for detection. Here, a new strategy for MALAT1 detection was proposed based on polyhedral nanogold-polyamide-amine dendrimers (PNG-PAMAMs). The SWCNH/Au composite was used as a capture probe immobilization matrix, and PNG-PAMAM was used as a trace label for the detection probe (DP). The strategy takes advantage of the ability of the surface of PNG to bind a capture probe whose sequence contains (GGG)₃ trimer that can bind DNAzyme hemin. Moreover, PNG may carry abundant horseradish peroxidases (HRPs) to block excess nonspecific adsorption sites, with synergistic hemin catalysis. The results show that the biosensor provides ultrasensitive detection of MALAT1 with a remarkable catalytic effect. The enhanced biosensor has a detection limit of 0.22 fmol·mL^− 1 for MALAT1, and the linear calibration of the biosensor ranged from 1 fmol·mL^− 1 to 100 pmol·mL^− 1. In addition, the electrochemical biosensor has desirable qualities compared to other detectors; for instance, it is inexpensive, highly stable, and sensitive and has good reproducibility. This assay was also successfully applied to the detection of MALAT1 in serum samples, demonstrating that the technology has potential application in the detection of MALAT1 for clinical HCC diagnosis.

Graphical Abstract

The schematic presentation ilustrates MALATI detection by biosensor with differential pulse stripping voltammetry. Polyhedral nanogold-PAMAM/horseradish peroxidases (PNG-PAMAM/HRP) detection probe with DNAzyme (hemin) sites was applied to determine MALATI. Signal was amplified by hemin/HRP/H₂O₂ catalytic system.

Electronic supplementary material

The online version of this article (10.1186/s13036-019-0149-4) contains supplementary material, which is available to authorized users.