DNAzyme-based ultrasensitive immunoassay: Recent advances and emerging trends.

Immunoassay, as the most commonly used method for protein detection, is simple to operate and highly specific. Sensitivity improvement is always the thrust of immunoassays, especially for the detection of trace quantities. The emergence of artificial enzyme, i.

Polydopamine Nanoparticles-Based Three-Line Lateral Flow Immunoassay for COVID-19 Detection.

Currently, the global trend of several hundred thousand new confirmed COVID-19 patients per day has not abated significantly. Serological antibody detection has become an important tool for the self-screening of people. While the most commonly used colorimetric lateral flow immunoassay (LFIA) methods for the detection of COVID-19 antibodies are limited by low sensitivity and a lack of quantification ability.

Similar color analysis based on deep learning (SCAD) for multiplex digital PCR a single fluorescent channel.

Digital PCR (dPCR) has recently attracted great interest due to its high sensitivity and accuracy. However, the existing dPCR depends on multicolor fluorescent dyes and multiple fluorescent channels to achieve multiplex detection, resulting in increased detection cost and limited detection throughput. Here, we developed a deep learning-based similar color analysis method, namely SCAD, to achieve multiplex dPCR in a single fluorescent channel.

Artificial intelligence-assisted colorimetric lateral flow immunoassay for sensitive and quantitative detection of COVID-19 neutralizing antibody.

Currently, vaccination is the most effective medical measure to improve group immunity and prevent the rapid spread of COVID-19. Since the individual difference of vaccine effectiveness is inevitable, it is necessary to evaluate the vaccine effectiveness of every vaccinated person to ensure the appearance of herd immunity. Here, we developed an artificial intelligent (AI)-assisted colorimetric polydopamine nanoparticle (PDA)-based lateral flow immunoassay (LFIA) platform for the sensitive and accurate quantification of neutralizing antibodies produced from vaccinations.

Quantifying and Adjusting Plasmon-Driven Nano-Localized Temperature Field around Gold Nanorods for Nucleic Acids Amplification.

Fast nucleic acid (NA) amplification has found widespread biomedical applications, where high thermocycling rate is the key. The plasmon-driven nano-localized thermocycling around the gold nanorods (AuNRs) is a promising alternative, as the significantly reduced reaction volume enables a rapid temperature response. However, quantifying and adjusting the nano-localized temperature field remains challenging for now.

A digitalized isothermal nucleic acid testing platform based on a pump-free open droplet array microfluidic chip.

Digital PCR has shown great potential for quantitative nucleic acid testing (NAT), but most existing platforms are dependent on large auxiliary equipment (, vacuum pump, amplification instrument, fluorescence microscope) to achieve target dispersion, amplification, signal capture and result analysis. Such complex, expensive and bulky NAT platforms have limited their applications in resource-limited areas, especially for point-of-care testing (POCT). In this work, we designed a digital isothermal NAT platform based on a pump-free open droplet array microfluidic chip.

A Portable Digital Loop-Mediated Isothermal Amplification Platform Based on Microgel Array and Hand-Held Reader.

Digital polymerase chain reaction (dPCR) has found widespread applications in molecular diagnosis of various diseases owing to its sensitive single-molecule detection capability. However, the existing dPCR platforms rely on the auxiliary procedure to disperse DNA samples, which needs complicated operation, expensive apparatus, and consumables. Besides, the complex and costly dPCR readers also impede the applications of dPCR for point-of-care testing (POCT).

Taqman-MGB nanoPCR for Highly Specific Detection of Single-Base Mutations.

Purpose: Detection of single-base mutations is important for real-time monitoring of tumor progression, therapeutic effects, and drug resistance. However, the specific detection of single-base mutations from excessive wild-type background sequences with routine PCR technology remains challenging. Our objective is to develop a simple and highly specific qPCR-based single-base mutation detection method.

A fast and ultrasensitive ELISA based on rolling circle amplification.

A highly sensitive ELISA is critical for early diagnosis and biomarker discovery of various diseases. Although various ELISA technologies have been developed with high sensitivity, they are limited by poor repeatability, high cost, the dependence on complex equipment and/or a prolonged reaction time. To this end, we developed a fast and ultrasensitive ELISA (termed RELISA) based on rolling circle amplification (RCA) and enzymatic signal amplification.

Microneedle patch for the ultrasensitive quantification of protein biomarkers in interstitial fluid.

The detection and quantification of protein biomarkers in interstitial fluid is hampered by challenges in its sampling and analysis. Here we report the use of a microneedle patch for fast in vivo sampling and on-needle quantification of target protein biomarkers in interstitial fluid. We used plasmonic fluor-an ultrabright fluorescent label-to improve the limit of detection of various interstitial fluid protein biomarkers by nearly 800-fold compared with conventional fluorophores, and a magnetic backing layer to implement conventional immunoassay procedures on the patch and thus improve measurement consistency.

Fully integrated microfluidic devices for qualitative, quantitative and digital nucleic acids testing at point of care.

Benefiting from emerging miniaturized and equipment-free nucleic acid testing (NAT) technologies, fully integrated NAT devices at point of care (POC) with the capability of "sample-in-answer-out" are proceeding at a break-neck speed to eliminate complex operations and reduce the risk of contamination. Like the development of polymerase chain reaction (PCR) technology (the standard technique for NAT), the detection signal of fully integrated NAT devices has evolved from qualitative to quantitative and recently to digital readout, aiming at expanding their extensive applications through gradually improving detection sensitivity and accuracy. This review firstly introduces the existing commercial products, and then illustrates recent fully integrated microfluidic devices for NAT at POC from the aspect of detection signals (i.

An upconversion nanoparticle-based photostable FRET system for long-chain DNA sequence detection.

The fluorescence resonance energy transfer (FRET)-based diagnosis method has been widely used in fast and accurate diagnosis. However, the traditional FRET-based diagnosis method is unable to detect long-chain DNA sequences, due to the limitation of the distance between the donor and acceptor, while the long-chain DNA sequence enables higher selectivity and is quite important for confirming many major diseases. Therefore, it is urgently needed to develop an efficient FRET system for long-chain DNA detection.

Ultrafast Photonic PCR Based on Photothermal Nanomaterials.

Over the past few decades, PCR has been the gold standard for detecting nucleic acids (NAs) in various biomedical fields. However, there are several limitations associated with conventional PCR, such as complicated operation, need for bulky equipment, and, in particular, long thermocycling time. Emerging nanomaterials with photothermal effects have shown great potential for developing a new generation of PCR: ultrafast photonic PCR.

Paper-based point-of-care immunoassays: Recent advances and emerging trends.

Immunoassay has been routinely used in hospitals and central labs. Nowadays, to further meet the requirement of widespread applications of immunoassays, it is urgently needed to produce a simplified, rapid and low-cost immunoassay to perform tests on site. To this end, paper-based point-of-care (POC) immunoassays have attracted intensive interests in recent years.

A portable and universal upconversion nanoparticle-based lateral flow assay platform for point-of-care testing.

Upconversion nanoparticle-based lateral flow assays (UCNP-LFAs) have attracted significant attention in point-of-care testing (POCT) applications, due to the long-term photostability and enhanced signal-to-background noise ratio. The existing UCNP-LFAs generally require peripheral equipment for exciting fluorescent signals and reading out fluorescence results, which are generally bulky and expensive. Herein, we developed a miniaturized and portable UCNP-LFA platform, which is composed of a LFA detection system, an UCNP-LFA reader and a smartphone-assisted UCNP-LFA analyzer.

Point-of-Care Periodontitis Testing: Biomarkers, Current Technologies, and Perspectives.

Periodontitis has become one of the most universal chronic inflammatory diseases worldwide. Subclinical symptom progression, ultimately leading to permanent damage, calls for early diagnosis and long-term monitoring. However, traditional clinical diagnostic methods are complex and expensive, and cannot meet these requirements.

Capillary blood for point-of-care testing.

Clinically, blood sample analysis has been widely used for health monitoring. In hospitals, arterial and venous blood are utilized to detect various disease biomarkers. However, collection methods are invasive, painful, may result in injury and contamination, and skilled workers are required, making these methods unsuitable for use in a resource-limited setting.

Pen-on-paper strategy for point-of-care testing: Rapid prototyping of fully written microfluidic biosensor.

Paper-based microfluidic biosensors have recently attracted increasing attentions in point-of-care testing (POCT) territories benefiting from their affordable, accessible and eco-friendly features, where technologies for fabricating such biosensors are preferred to be equipment free, easy-to-operate and capable of rapid prototyping. In this work, we developed a pen-on-paper (PoP) strategy based on two custom-made pens, i.e.

Improved LFIAs for highly sensitive detection of BNP at point-of-care.

Heart failure (HF) has become a major cause of morbidity and mortality with a significant global economic burden. Although well-established clinical tests could provide early diagnosis, access to these tests is limited in developing countries, where a relatively higher incidence of HF is present. This has prompted an urgent need for developing a cost-effective, rapid and robust diagnostic tool for point-of-care (POC) detection of HF.

Household Fluorescent Lateral Flow Strip Platform for Sensitive and Quantitative Prognosis of Heart Failure Using Dual-Color Upconversion Nanoparticles.

Heart failure (HF) is the end-stage of cardiovascular diseases, which is associated with a high mortality rate and high readmission rate. Household early diagnosis and real-time prognosis of HF at bedside are of significant importance. Here, we developed a highly sensitive and quantitative household prognosis platform (termed as UC-LFS platform), integrating a smartphone-based reader with multiplexed upconversion fluorescent lateral flow strip (LFS).

A fully disposable and integrated paper-based device for nucleic acid extraction, amplification and detection.

Nucleic acid testing (NAT) has been widely used for disease diagnosis, food safety control and environmental monitoring. At present, NAT mainly involves nucleic acid extraction, amplification and detection steps that heavily rely on large equipment and skilled workers, making the test expensive, time-consuming, and thus less suitable for point-of-care (POC) applications. With advances in paper-based microfluidic technologies, various integrated paper-based devices have recently been developed for NAT, which however require off-chip reagent storage, complex operation steps and equipment-dependent nucleic acid amplification, restricting their use for POC testing.

Antiproliferative Activity and Cellular Uptake of Evodiamine and Rutaecarpine Based on 3D Tumor Models.

Evodiamine (EVO) and rutaecarpine (RUT) are promising anti-tumor drug candidates. The evaluation of the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids of cancer cells would better recapitulate the native situation and thus better reflect an in vivo response to the treatment. Herein, we employed the 3D culture of MCF-7 and SMMC-7721 cells based on hanging drop method and evaluated the anti-proliferative activity and cellular uptake of EVO and RUT in 3D multicellular spheroids, and compared the results with those obtained from 2D monolayers.

Labeling and long-term tracking of bone marrow mesenchymal stem cells in vitro using NaYF4:Yb(3+),Er(3+) upconversion nanoparticles.

Unlabelled: Mesenchymal stem cells (MSCs) hold great promise as cell therapy candidate in clinics. However, the underlying mechanisms remain elusive due to the lack of effective cell tracking approaches during therapeutic processes. In this study, we successfully synthesized and utilized NaYF4:Yb(3+),Er(3+) upconversion nanoparticles (UCNPs) to label and track rabbit bone marrow mesenchymal stem cells (rBMSCs) during the osteogenic differentiation in vitro.

Three-dimensional quick response code based on inkjet printing of upconversion fluorescent nanoparticles for drug anti-counterfeiting.

Medicine counterfeiting is a serious issue worldwide, involving potentially devastating health repercussions. Advanced anti-counterfeit technology for drugs has therefore aroused intensive interest. However, existing anti-counterfeit technologies are associated with drawbacks such as the high cost, complex fabrication process, sophisticated operation and incapability in authenticating drug ingredients.