Afterglow Nanoprobe-Enabled Quantitative Lateral Flow Immunoassay by a Palm-Size Device for Household Healthcare.

Lateral flow immunoassay (LFIA), a classical point-of-care testing (POCT) technique, plays an important role in disease screening and healthcare monitoring. However, traditional LFIA is either designed for qualitative analysis or requires expensive equipment for quantification, limiting its use in household diagnosis. In this study, we proposed a new generation of LFIA for household health monitoring by using ultralong organic phosphorescence (UOP) nanomaterials as afterglow nanoprobes with a self-developed palm-size sensing device. The UOP nanoprobes exhibit a phosphorescence signal with a second-level lifetime, which completely avoids the interference from excitation light and biological background fluorescence. Therefore, an ultraminiaturized and low-cost UOP nanosensor was successfully designed by eliminating the complex optical path and filtering systems. We chose an inflammatory factor, C-reactive protein (CRP), for household POCT validation. The whole analysis was completed within 9 min. A limit of detection (LOD) of 0.54 ng/mL of CRP antigen was achieved with high stability and good specificity, which is comparable to laboratory instruments and fully satisfying the clinical diagnosis requirement.

Magnetic nanoprobe-enabled lateral flow assays: recent advances.

In recent years, magnetic nanoparticle sensor technologies have attracted considerable interest in the point-of-care-testing (POCT) field, especially in lateral flow immunoassays (LFIAs). Although the visual signal of magnetic nanoparticles is reduced during an inspection, it can be compensated for by magnetic induction, and detection results can be quantified by magnetic sensors. Sensors that use magnetic nanoparticles (MNPs) as markers can overcome the high background noise of complex samples. In this study, MNP signal detection strategies are described from the perspectives of magnetoresistance, magnetic flux, frequency mixing technology, and magnetic permeability, and the principles and development of each technology are introduced in detail. Typical applications of magnetic nanoparticle sensor technologies are introduced. By describing the advantages and limitations of different sensing strategies, we highlight the development and improvement directions of different sensing strategies. In general, the future development of magnetic nanoparticle sensor technologies will be toward intelligent, convenient, and mobile high-performance detection equipment.

Portable dual-channel blood enzyme analyzer for point-of-care liver function detection.

Because the liver is an important metabolic center in the human body, the reliability and timeliness of chronic liver disease diagnosis are particularly important. Alanine aminotransferase and aspartate transaminase are the two most important liver function indicators, and their test results are crucial in the diagnosis of liver diseases. However, the simultaneous detection of these two indicators is currently restricted by the need for expensive equipment and complicated detection processes. This study proposes a portable dual-channel blood enzyme analyzer (BEA) for point-of-care-testing. The device uses photometric reflectance to quantify the enzyme concentration by evaluating the reflected light intensity. The BEA also precisely controls and maintains the temperature at 37 °C ± 0.1 °C in the dual-channel assay. We assessed the responses of this system within a clinically relevant range by testing blood samples from a local hospital. The test verified that BEA for ALT and AST achieved a detection limit of 3.5 U L-1 and 4 U L-1, detection range of 4-350 U L-1 and 4-250 U L-1, coefficients of variation (CV) that were both less than 10%, and a linear correlation coefficient of 0.9827 and 0.9714 compared with a high-precision clinical biochemistry analyzer (Roche Cobas C702), respectively. We realized remote data analysis and storage through connection with smartphones, which can be applied to remote diagnostics and preventative personal disease management. Therefore, BEA has broad application prospects in the future internet of medical things.

Surface plasmonic biosensors: principles, designs and applications.

Recently, surface plasmon resonance (SPR) biosensors have been widely used in environmental monitoring, food contamination detection and diagnosing medical conditions due to their superior sensitivity, label-free detection and rapid analysis speed. This paper briefly elaborates on the development history of SPR technology and introduces SPR signal sensing principles. A summary of recent applications of SPR sensors in different fields is highlighted, including their figures of merit and limitations. Finally, the personal perspectives and future development trends about sensor preparation and design are discussed in detail, which may be critical for improving the performance of SPR sensors.

HS-GC-IMS Analysis of Volatile Organic Compounds in Different Varieties and Harvesting Times of Rhizoma gastrodiae (Tian Ma) in Yunnan Province.

Headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) coupled with principal component analysis (PCA) was used to investigate the differences in volatile organic compounds (VOCs) in four different varieties of Yunnan Huang Tian Ma (containing both winter and spring harvesting times), Yunnan Hong Tian Ma, Yunnan Wu Tian Ma, and Yunnan Lv Tian Ma. The results showed that the flavor substances of different varieties and different harvesting times of Rhizoma gastrodiae were mainly composed of aldehydes, alcohols, ketones, heterocycles, esters, acids, alkenes, hydrocarbons, amines, phenols, ethers, and nitrile. Among them, the contents of the aldehydes, alcohols, ketones, and heterocyclic compounds are significantly higher than those of other substances. The results of cluster analysis and fingerprint similarity analysis based on principal component analysis and Euclidean distance showed that there were some differences between different varieties of Yunnan Rhizoma gastrodiae and different harvesting times. Among them, Yunnan Lv Tian Ma and Wu Tian Ma contained the richest volatile components. Winter may be the best harvesting season for Tian Ma. At the same time, we speculate that the special odor contained in Tian Ma should be related to the aldehydes it is rich in, especially benzene acetaldehyde, Benzaldehyde, Heptanal, Hexanal, Pentanal, and butanal, which are aldehydes that contain a strong and special odor and are formed by the combination of these aldehydes.

A lab-on-disc centrifugal microfluidic system for ultraprecise plasma separation.

As the medical community puts forward higher requirements for the speed and convenience of disease diagnosis, point-of-care testing has become a hot research topic to overcome various kinds of healthcare problems. Blood test is considered to be highly sensitive and accurate in clinical diagnosis. However, conventional plasma separation system tends to be bulky and needs professional operations. Moreover, imprecise separation may cause residual biochemical substances such as blood cells to affect the detection results. In this work, to solve these problems, we designed a portable centrifugal microfluidic platform for automatic, rapid and ultraprecise blood separation. The disc consists of multichambers and multi-microchannels where a plasma reservoir and a cell reservoir are connected to each other and collinear with the center of the circle. This structure overcomes the weakness of low separation efficiency (when hematocrit increases) under the traditional blood separation structure (bifurcation structure). As a result, the proposed system achieved 99.9% plasma purity, 99.9% separation efficiency (with a blood hematocrit of 48%) and 32.5% plasma recovery rate in the 50s, which provides a strong guarantee for rapid blood diagnosis and analysis, especially in areas where medical resources are limited.

Smartphone-based photochemical sensor for multiplex determination of glucose, uric acid, and total cholesterol in fingertip blood.

A smartphone-based photochemical biosensor capable of realizing multiplex detection of glucose, uric acid (UA), and total cholesterol (TC) is reported here for the first time. The system was composed of a photochemical dongle, a cloud-enabled smartphone, and disposable test strips. The dongle was controlled using a microcontroller unit and was designed to convert the reflected light's intensities into optoelectronic signals for analytes quantification. Only 30 µL of the fingertip blood is needed to complete accurate and reliable measurements within 2 minutes. A cloud-enabled smartphone is connected to the dongle via Bluetooth to serve as a data receiver, and users can obtain the test results for proactive health management or remote diagnosis, while powering the dongle. We believe the proposed biosensor will contribute a lot to the point-of-care-testing and has promising prospects in contributing to the development of the Internet of Medical Things.

An automatic whole blood analyzer for renal function analysis with a centrifugal microfluidic device.

In recent years, chronic kidney disease (CKD) has received widespread attention as one of the fastest growing non-communicable diseases (NCD) worldwide. Here, a clinical biochemical detection system based on a centrifugal microfluidic chip was designed to simplify the rapid detection of renal function indices. A photosensor was used to design an optical signal acquisition structure that can detect products or substrates after enzymatic reactions of uric acid, creatinine, and urea. The weak optical signals collected from this structure were processed using a pre-designed amplifying circuit and a software algorithm to calculate absorbance. The relationship between absorbance and concentration was established according to the Beer-Lambert law. The results indicated good stability and accuracy of the system, which is 21.3 cm × 16.5 cm × 19 cm in size as compared to other detection systems due to the adoption of a centrifugal microfluidic chip. It was portable and easy to operate, in addition to its ability to rapidly detect renal function indices. This system exhibits great potential for the detection of highly integrated point-of-care testing in the future.

A low-cost compact blood enzyme analyzer based on optical sensing for point-of-care liver function testing.

Serum alanine aminotransferase (ALT) is the most sensitive indicator of liver function; therefore, in clinical practice, its detection has diagnostic significance. However, hepatotoxicity monitoring is constrained in resource-limited areas due to the high cost and expensive equipment. This article describes a low-cost, compact blood enzyme analyzer (BEA) for point-of-care (PoC) liver function testing that uses reflection photometry to quantitate the colorimetric enzyme assay results. Moreover, the analyzer incorporates rapid and constant 37 °C temperature control to ensure that human serum enzymes remain active. The BEA was used to evaluate ALT in 50 whole blood samples using PoC photochemical test strips. The test results showed a linear correlation coefficient of 0.9749 compared with a clinical-specific biochemical analyzer and coefficients of variation (CV)% less than 5%. It has a low detection limit of 3.62 U L-1 and a wide detection range of 4-480 U L-1. In addition, the BEA enables smartphone access to the Internet of Medical Things (IoMT) via Bluetooth to facilitate active chronic disease management or remote diagnosis in PoC settings. Therefore, the BEA is a promising system for health management using the IoMT.

Microfluidic flow cytometry for blood-based biomarker analysis.

Flow cytometry has proven its capability for rapid and quantitative analysis of individual cells and the separation of targeted biological samples from others. The emerging microfluidics technology makes it possible to develop portable microfluidic diagnostic devices for point-of-care testing (POCT) applications. Microfluidic flow cytometry (MFCM), where flow cytometry and microfluidics are combined to achieve similar or even superior functionalities on microfluidic chips, provides a powerful single-cell characterisation and sorting tool for various biological samples. In recent years, researchers have made great progress in the development of the MFCM including focusing, detecting, and sorting subsystems, and its unique capabilities have been demonstrated in various biological applications. Moreover, liquid biopsy using blood can provide various physiological and pathological information. Thus, biomarkers from blood are regarded as meaningful circulating transporters of signal molecules or particles and have great potential to be used as non (or minimally)-invasive diagnostic tools. In this review, we summarise the recent progress of the key subsystems for MFCM and its achievements in blood-based biomarker analysis. Finally, foresight is offered to highlight the research challenges faced by MFCM in expanding into blood-based POCT applications, potentially yielding commercialisation opportunities.

3D printed microfluidic Coulter counter for blood cell analysis.

Coulter counters are ubiquitous in everyday life; however, with reduced orifice size shrinkage, there is an increased risk of clogging. Herein, a 3D microfluidic printing-based single-use kit is presented for analyzing biological samples and performing accurate Coulter cell count analysis (e.g., white blood cells in the blood). The gem hole eliminates the traditional design concept of integration inside the detection instrument, innovatively causing it to be independent from the analysis instrument. Further, integrating the hole in the analysis box enables the design of a separate detection module. The analysis box is disposable, convenient, and hygienic; avoids cross-infection; solves the problem of clogging of tiny holes from a new perspective; and no longer requires uneconomical and inconvenient methods, such as flushing, cauterization, and fluid focusing, through solid water flow. Further development of the newly designed 3D printing analysis box can enable its extensive use in POCT (point-of-care) detection scenarios. Moreover, through mass production, the issue of cost will be eliminated.

Integrated electrochemical lateral flow immunoassays (eLFIAs): recent advances.

The discovery of electroactive nano-biomaterials and the development of flexible electrodes have increased the interest in applications of integrated electrochemical lateral flow immunoassays (eLFIAs), which integrate electrochemical nanotags and flexible electrodes on test strips that can easily detect small biomolecules. Compared with colorimetric, optical, magnetic and other highly sensitive detection methods, the electrochemical detection technique is well developed with high sensitivity, selectivity and repeatability. Moreover, the increasing compatibility of interfaces with miniature potentiometers has allowed electrochemical sensors to become more integrated, automated and intelligent, highlighting their huge potential in future developments. This review discusses the relevant eLFIA research over the past 20 years. The basic principles, electrode assemblies, electrochemical labeling strategies and electrical signal detection methods are summarized and analyzed in detail. Finally, perspectives on the current challenges facing eLFIA and its future outlook are presented.

Self-propelled Janus nanomotor as active probe for detection of pepsinogen by lateral flow immunoassay.

The feasibility of using nanomotors as active probes for lateral flow immunoassay (LFIA) is demonstrated. We synthesized Au@mSiO2@Pt Janus nanomotor, where nanolayer of Pt was deposited on the half side surface of the Au@mSiO2 nanoparticles, which can catalyze the decomposition of H2O2 to produce driving force for the nanomotor. Subsequently, the motion characteristics of the Au@mSiO2@Pt nanomotor in static fluidic environment and dynamic flow field was studied to pave the way for its practical application in lateral flow immunoassay (LFIA). At last, the Au@mSiO2@Pt nanomotor was modified with antibody and then used as active immunoassay probe in LFIA. We chose gastric function index, pepsinogen II (PG II) and pepsinogen II (PG II), as the target analytes. The results indicated that, compared with traditional Au nanoprobe, the nanomotor-based probe can significantly improve the sensitivity by increasing the probability and efficiency of antigen and antibody binding. A limit of detection (LOD) of 2.2 ng/mL for PGI, and 2.1 ng/mL for PG II was achieved. This work provides a new solution for enhancing the capability of immune detection, and we believe the nanomotor-based LFIA will have great potential in high-sensitivity point-of-care-testing in the future.

Academic-clinical nursing partnership use an evidence-based practice model.

AIMS AND OBJECTIVES: The purpose of this study was to compare the experience of a new clinical model with traditional clinical teaching and examine the effects of evidence-based practice strategies among staff and student nurses. BACKGROUND: This provides an innovative approach to nursing student clinical learning that emphasised the academic-clinical partnership with the use of a new model called the Evidence-based Clinical Academic Partnership (ECAP) model. The model incorporates three main components (a) unit transformation into an innovative hybrid version of a dedicated education unit (hDEU); (b) Evidence-in-Action (EIA) rounding; and (c) the cognitive apprenticeship theoretical framework. DESIGN: This pilot study used a mixed-method, quasi-experimental design. METHODS: The quantitative portion included a pre-test, post-test non-randomised quasi-experimental design using self-reported survey data. The qualitative methodology used was a hermeneutic phenomenological approach to data interpretation of three focus groups with staff nurses and unit leaders. SQUIRE 2.0 guidelines were followed (Ogrinc et al., 2016). CONCLUSIONS: The themes that emerged emphasised relationships and the partnership with this innovative approach to clinical teaching. The staff nurses emphasised the need for a collaborative approach and having the presence of the academic faculty member as a way to support the teaching and learning aspects with students. RELEVANCE TO CLINICAL PRACTICE: This study did provide significant contributions to the development of an innovative clinical model and highlighted the importance of the academic-clinical partnership with the education of undergraduate nursing students. The study results provided insight to the ways the hDEU framework may be strengthened, such as increased communication and partnership in the implementation of the ECAP model. Implementing curricular change to include innovative clinical models within a nursing programme is vital in this time of healthcare transformation.

Instant Preparation of Ultraclean Gold Nanothorns under Ambient Conditions for SERS Kit-Enabled Mobile Diagnosis.

Availability of surface-enhanced Raman scattering (SERS) substrates with good stability, high sensitivity, and a clean surface is crucial for the practical usefulness of the SERS technology in biochemical sensing, especially for point-of-care testing (POCT). Hereby, we develop a "ready-to-use" SERS kit, which requires only 20 s to fabricate ultraclean gold nanothorn (AuNT)-based SERS chips under ambient conditions with simple solution processing steps. By varying the thickness of the pre-coated platinum (Pt) nanolayer, we can control the size and number density of the grown AuNT. Taking advantage of the ultraclean surface of the instantly obtained fresh AuNT, Raman reporter molecules can also be immediately modified, by means of which specific detection of three analytes including H2O2, NO2-, and ClO- is realized. Furthermore, we propose the concept of an SERS kit and apply it to smartphone-based Raman analysis for POCT applications. This on-site preparation method solves the long-standing challenges hindering the practical use of SERS substrates, such as complicated fabrication processes, interference of residual surfactants, poor surface stability, and easy contamination. Besides performing SERS analysis conveniently and quickly, this SERS kit-enabled POCT technology can integrate remote data terminals and medical resources, which shows great potential for environmental protection or online-healthcare systems.

A miniaturized giant magnetic resistance system for quantitative detection of methamphetamine.

Point-of-care testing (POCT) systems have been greatly developed in recent years. Among them, lateral flow immunoassay (LFIA) based on magnetic nanoparticles (MNPs) is widely used in various fields due to the advantages of small background noise and good biocompatibility. This paper designed an ultra-sensitive giant magnetic resistance (GMR) system for the quantitative detection of methamphetamine (MET). The system uses GMRs to detect the distribution of the magnetic field intensity of MNPs captured by the test (T) and control (C) lines on LFIA. A special external interference cancellation (EIC) method and a weak-signal waveform reconstruction method were used to improve the accuracy of the detection. Finally, the T/C ratio was calculated to realize the quantitative detection of MET. The result showed good linear performance with a detection limit of 0.1 ng mL-1. The system can also be used in other fields such as disease detection, food analysis, and environmental testing.

Quantitative detection of morphine based on an up-conversion luminescent system.

An up-conversion luminescent material converts low-frequency excitation light into high-frequency emission light through photons and has the advantages of long fluorescence lifetime, narrow emission peak and low toxicity; thus, this material has many unique applications in the detection and identification of biomolecules. In this study, an ultrasensitive up-conversion luminescent system for the quantitative detection of morphine was developed. The principle of this system is based on infrared light as an excitation light source to convert light with lower energy into excitation light with higher energy. The up-conversion luminescent material is used as a label and through the processing and analysis of the excitation light intensity, the quantitative detection of morphine concentration is achieved. At the same time, the excitation light can avoid the interference and scattering phenomenon of the autofluorescence of the biological sample, which improves the system's detection sensitivity. An algorithm for light intensity processing is added to process image data, reduce the interference caused by noise during image acquisition and improve the accuracy of morphine detection. The T/C value is calculated to achieve the quantitative detection of morphine with a detection limit of 0.1 ng mg-1 and detection time within 0.5 min. The up-conversion luminescent system has the advantages of quantitative detection, convenience, portability, short detection time and low price. Thus, the system can be used for the detection of other biomolecules or for other applications such as food analysis, environmental detection, national security, etc.

Application of centrifugal microfluidics in immunoassay, biochemical analysis and molecular diagnosis.

Rapid diagnosis plays a vital role in daily life and is effective in reducing treatment costs and increasing curability, especially in remote areas with limited availability of resources. Among the various common methods of rapid diagnosis, centrifugal microfluidics has many unique advantages, such as less sample consumption, more precise valve control for sequential loading of samples, and accurately separated module design in a microfluidic network to minimize cross-contamination. Therefore, in recent years, centrifugal microfluidics has been extensively researched, and it has been found to play important roles in biology, chemistry, and medicine. Here, we review the latest developments in centrifugal microfluidic platforms in immunoassays, biochemical analyses, and molecular diagnosis, in recent years. In immunoassays, we focus on the application of enzyme-linked immunosorbent assay (ELISA); in biochemical analysis, we introduce the application of plasma and blood cell separation; and in molecular diagnosis, we highlight the application of nucleic acid amplification tests. Additionally, we discuss the characteristics of the methods under each platform as well as the enhancement of the corresponding performance parameters, such as the limit of detection, separation efficiency, etc. Finally, we discuss the limitations associated with the existing applications and potential breakthroughs that can be achieved in this field in the future.

5G-Enabled intelligent construction of a chest pain center with up-conversion lateral flow immunoassay.

Acute myocardial infarction (AMI) has become a worldwide health problem because of its rapid onset and high mortality. Cardiac troponin I (cTnI) is the gold standard for diagnosis of AMI, and its rapid and accurate detection is critical for early diagnosis and management of AMI. Using a lateral flow immunoassay with upconverting nanoparticles as fluorescent probes, we developed an up-conversion fluorescence reader capable of rapidly quantifying the cTnI concentration in serum based upon the fluorescence intensity of the test and control lines on the test strip. Reliable detection of cTnI in the range 0.1-50 ng mL-1 could be achieved in 15 min, with a lower detection limit of 0.1 ng mL-1. The reader was also adapted for use on a 5th generation (5G) mobile network enabled intelligent chest pain center. Through Bluetooth wireless communication, the results achieved using the reader on an ambulance heading to a central hospital could be transmitted to a 5G smartphone and uploaded for real-time edge computing and cloud storage. An application in the 5G smartphone allows users to upload their medical information to establish dedicated electronic health records and doctors to monitor patients' health status and provide remote medical services. Combined with mobile internet and big data, the 5G-enabled intelligent chest pain center with up-conversion lateral flow immunoassay may predict the onset of AMI and save valuable time for patients suffering an AMI.

Recent progress of inertial microfluidic-based cell separation.

Cell separation has consistently been a pivotal technology of sample preparation in biomedical research. Compared with conventional bulky cell separation technologies applied in the clinic, cell separation based on microfluidics can accurately manipulate the displacement of liquid or cells at the microscale, which has great potential in point-of-care testing (POCT) applications due to small device size, low cost, low sample consumption, and high operating accuracy. Among various microfluidic cell separation technologies, inertial microfluidics has attracted great attention due to its simple structure and high throughput. In recent years, many researchers have explored the principles and applications of inertial microfluidics and developed different channel structures, including straight channels, curved channels, and multistage channels. However, the recently developed multistage channels have not been discussed and classified in detail compared with more widely discussed straight and curved channels. Therefore, in this review, a comprehensive and detailed review of recent progress in the multistage channel is presented. According to the channel structure, the inertial microfluidic separation technology is divided into (i) straight channel, (ii) curved channel, (iii) composite channel, and (iv) integrated device. The structural development of straight and curved channels is discussed in detail. And based on straight and curved channels, the multistage cell separation structures are reviewed, with a special focus on a variety of latest structures and related innovations of composite and integrated channels. Finally, the future prospects for the existing challenges in the development of inertial microfluidic cell separation technology are presented.