Thermophoretic glycan profiling of extracellular vesicles for triple-negative breast cancer management.

Triple-negative breast cancer (TNBC) is a highly metastatic and heterogeneous type of breast cancer with poor outcomes. Precise, non-invasive methods for diagnosis, monitoring and prognosis of TNBC are particularly challenging due to a paucity of TNBC biomarkers. Glycans on extracellular vesicles (EVs) hold the promise as valuable biomarkers, but conventional methods for glycan analysis are not feasible in clinical practice. Here, we report that a lectin-based thermophoretic assay (EVLET) streamlines vibrating membrane filtration (VMF) and thermophoretic amplification, allowing for rapid, sensitive, selective and cost-effective EV glycan profiling in TNBC plasma. A pilot cohort study shows that the EV glycan signature reaches 91% accuracy for TNBC detection and 96% accuracy for longitudinal monitoring of TNBC therapeutic response. Moreover, we demonstrate the potential of EV glycan signature for predicting TNBC progression. Our EVLET system lays the foundation for non-invasive cancer management by EV glycans.

DNA-Based Nanomaterials for Analysis of Extracellular Vesicles.

Extracellular vesicles (EVs) are cell-derived nanovesicles comprising a myriad of molecular cargo such as proteins and nucleic acids, playing essential roles in intercellular communication and physiological and pathological processes. EVs have received substantial attention as noninvasive biomarkers for disease diagnosis and prognosis. Owing to their ability to recognize protein and nucleic acid targets, DNA-based nanomaterials with excellent programmability and modifiability provide a promising tool for the sensitive and accurate detection of molecular cargo carried by EVs. In this perspective, recent advancements in EV analysis using a variety of DNA-based nanomaterials are summarized, which can be broadly classified into three categories: linear DNA probes, DNA nanostructures, and hybrid DNA nanomaterials. The design, construction, advantages, and disadvantages of different types of DNA nanomaterials, as well as their performance for detecting EVs are reviewed. The challenges and opportunities in the field of EV analysis by DNA nanomaterials are also discussed.

Selective In Situ Analysis of Mature microRNAs in Extracellular Vesicles Using a DNA Cage-Based Thermophoretic Assay.

Mature microRNAs (miRNAs) in extracellular vesicles (EVs) are involved in different stages of cancer progression, yet it remains challenging to precisely detect mature miRNAs in EVs due to the presence of interfering RNAs (such as longer precursor miRNAs, pre-miRNAs) and the low abundance of tumor-associated miRNAs. By leveraging the size-selective ability of DNA cages and polyethylene glycol (PEG)-enhanced thermophoretic accumulation of EVs, we devised a DNA cage-based thermophoretic assay for highly sensitive, selective, and in situ detection of mature miRNAs in EVs with a low limit of detection (LoD) of 2.05 fM. Our assay can profile EV mature miRNAs directly in serum samples without the interference of pre-miRNAs and the need for ultracentrifugation. A clinical study showed that EV miR-21 or miR-155 had an overall accuracy of 90 % for discrimination between breast cancer patients and healthy donors, which outperformed conventional molecular probes detecting both mature miRNAs and pre-miRNAs. We envision that our assay can advance EV miRNA-based diagnosis of cancer.

Cascaded microfluidic circuits for pulsatile filtration of extracellular vesicles from whole blood for early cancer diagnosis.

Tumor-derived extracellular vesicles (EVs) hold the potential to substantially improve noninvasive early diagnosis of cancer. However, analysis of nanosized EVs in blood samples has been hampered by lack of effective, rapid, and standardized methods for isolating and detecting EVs. To address this difficulty, here we use the electric-hydraulic analogy to design cascaded microfluidic circuits for pulsatile filtration of EVs via integration of a cell-removal circuit and an EV-isolation circuit. The microfluidic device is solely driven by a pneumatic clock pulse generator, allowing for preprogrammed, clog-free, gentle, high-yield, and high-purity isolation of EVs directly from blood within 30 minutes. We demonstrate its clinical utility by detecting protein markers of isolated EVs from patient blood using a polyethylene glycol-enhanced thermophoretic aptasensor, with 91% accuracy for diagnosis of early-stage breast cancer. The cascaded microfluidic circuits can have broad applications in the field of EV research.

One-Step Thermophoretic AND Gate Operation on Extracellular Vesicles Improves Diagnosis of Prostate Cancer.

Circulating extracellular vesicles (EVs) have emerged as a valuable source of cancer biomarkers. However, the high degree of EV heterogeneity and the complexity of clinical samples pose a challenge in the sensitive identification of tumor-derived EVs. Here we introduce a one-step thermophoretic AND gate operation (Tango) assay that integrates polyethylene glycol (PEG)-enhanced thermophoretic accumulation of EVs and simultaneous AND gate operation on EV membranes by dual-aptamers recognition. By using the Tango assay to detect tumor-derived EVs with co-presence of EpCAM and PSMA directly from serum in a homogeneous, separation-free format, we can discriminate prostate cancer (PCa) patients from benign prostatic hyperplasia (BPH) patients in the diagnostic gray zone with an accuracy of 91 % in 15 min. Our approach streamlines EV enrichment and AND gate operation on EVs in a single assay, providing a rapid, straightforward, and powerful method for precise and non-invasive diagnosis of cancer.

Cost-effectiveness analysis of the prevention of mother-to-child transmission of HIV.

BACKGROUND: The number of HIV-positive pregnant women accounted for about 10% of China's total over the past few years in Liangshan Prefecture, Sichuan province in China. Although cost-effectiveness of the PMTCT of HIV have been evaluated in other previous studies, no specific study has been conducted in Liangshan prefecture, nor has the expenses paid individually by HIV-positive pregnant women been included. The purpose of this study was to evaluate both the short-term and long-term cost-effectiveness of PMTCT of HIV in Liangshan Prefecture from the social perspective. METHODS: From December 2018 to January 2019, individual expenses and the other costs were collected: individual expenses of 133 recruited HIV-positive pregnant women registered in the National Information System of Prevention of Mother-to-Child Transmission of HIV, Syphilis, and HBV, and the other costs from local maternal and child healthcare hospitals, Centers for Disease Control and Prevention, and general hospitals. The costs, the number of pediatric infections averted from being HIV infected were analyzed. And, Life years gained by pediatric infections averted were calculated by using a life table. Besides, Direct benefit was calculated through a Markov mode. Furthermore, One-way sensitivity analysis was conducted for key variables affecting the benefit-cost ratio. RESULTS: The estimated number of pediatric infections averted was 164.The total cost was USD 114.1 million, including direct medical costs, direct non-medical costs, and indirect costs, which were USD 54.2 million, USD 53.4 million, and USD 6.5 million, respectively. 630.6 person-years discounted to 2017 were gained at a 3% annual rate, and cost per life year gained was USD 1809.50. Direct benefits were USD 198.4 million, indirect benefits USD 82.5 million, and the benefit-cost ratio was 1.5. The sensitivity analysis showed that if PMTCT costs hypothetically ranged from USD 85.6 million to USD 142.6 million, benefit-cost ratio would vary from 1.0 to 2.3. CONCLUSIONS: PMTCT of HIV in Liangshan Prefecture was very cost-effective. It was a great economic burden of PMTCT on HIV-positive pregnant women and their families to take individual expenses. Therefore, it could be suggested that individual expenses should be covered as much as possible by different types of financing.

Rapid One-Step Detection of Viral Particles Using an Aptamer-Based Thermophoretic Assay.

Rapid and sensitive identification of viral pathogens such as SARS-CoV-2 is a critical step to control the pandemic disease. Viral antigen detection can compete with gold-standard PCR-based nucleic acid diagnostics in terms of better reflection of viral infectivity and reduced risk of contamination from enzymatic amplification. Here, we report the development of a one-step thermophoretic assay using an aptamer and polyethylene glycol (PEG) for direct quantitative detection of viral particles. The assay relies on aptamer binding to the spike protein of SARS-CoV-2 and simultaneous accumulation of aptamer-bound viral particles in laser-induced gradients of temperature and PEG concentration. Using a pseudotyped lentivirus model, a limit of detection of ∼170 particles µL-1 (26 fM of the spike protein) is achieved in 15 min without the need of any pretreatment. As a proof of concept, the one-step thermophoretic assay is used to detect synthetic samples by spiking viral particles into oropharyngeal swabs with an accuracy of 100%. The simplicity, speed, and cost-effectiveness of this thermophoretic assay may expand the diagnostic tools for viral pathogens.

Protein analysis of extracellular vesicles to monitor and predict therapeutic response in metastatic breast cancer.

Molecular profiling of circulating extracellular vesicles (EVs) provides a promising noninvasive means to diagnose, monitor, and predict the course of metastatic breast cancer (MBC). However, the analysis of EV protein markers has been confounded by the presence of soluble protein counterparts in peripheral blood. Here we use a rapid, sensitive, and low-cost thermophoretic aptasensor (TAS) to profile cancer-associated protein profiles of plasma EVs without the interference of soluble proteins. We show that the EV signature (a weighted sum of eight EV protein markers) has a high accuracy (91.1 %) for discrimination of MBC, non-metastatic breast cancer (NMBC), and healthy donors (HD). For MBC patients undergoing therapies, the EV signature can accurately monitor the treatment response across the training, validation, and prospective cohorts, and serve as an independent prognostic factor for progression free survival in MBC patients. Together, this work highlights the potential clinical utility of EVs in management of MBC.

Molecular Identification of Tumor-Derived Extracellular Vesicles Using Thermophoresis-Mediated DNA Computation.

Molecular profiling of tumor-derived extracellular vesicles (tEVs) holds great promise for non-invasive cancer diagnosis. However, sensitive and accurate identification of tEVs is challenged by the heterogeneity of EV phenotypes which reflect different cell origins. Here we present a DNA computation device mediated by thermophoresis for detection of tEVs. The strategy leverages the aptamer-based logic gate using multiple protein biomarkers on single EVs as the input and thermophoretic accumulation to amplify the output signals for highly sensitive and specific profiling of tEVs. Employing this platform, we demonstrate a high accuracy of 97% for discrimination of breast cancer (BC) patients and healthy donors in a clinical cohort (n = 30). Furthermore, molecular phenotyping assessed by tEVs is in concordance with the results from tissue biopsy in BC patients. The thermophoresis-mediated molecular computation on EVs thus provides new opportunities for accurate detection and classification of cancers.

Nucleic Acids Analysis.

Nucleic acids are natural biopolymers of nucleotides that store, encode, transmit and express genetic information, which play central roles in diverse cellular events and diseases in living things. The analysis of nucleic acids and nucleic acids-based analysis have been widely applied in biological studies, clinical diagnosis, environmental analysis, food safety and forensic analysis. During the past decades, the field of nucleic acids analysis has been rapidly advancing with many technological breakthroughs. In this review, we focus on the methods developed for analyzing nucleic acids, nucleic acids-based analysis, device for nucleic acids analysis, and applications of nucleic acids analysis. The representative strategies for the development of new nucleic acids analysis in this field are summarized, and key advantages and possible limitations are discussed. Finally, a brief perspective on existing challenges and further research development is provided.

Nanosensors for Diagnosis of Infectious Diseases.

Infectious diseases have become a severe global public health problem. Timely and accurate diagnosis of infected individuals is the key step to control the spread of infectious diseases. Nanosensors that combine the advantages of nanomaterials and biosensing technology have been utilized for sensitive, selective, and rapid disease diagnosis and gained great attention within the chemistry, biology, and medical communities. This review presents a broad overview of a wide range of nanosensors for diagnosis of infectious diseases using different methodologies. We also outline point-of-care nanosensing methods and discuss their use in pathogen detection. This review concludes with challenges and opportunities for diagnosis of infectious diseases using nanosensors.

A fully automated centrifugal microfluidic system for sample-to-answer viral nucleic acid testing.

The outbreak of virus-induced infectious diseases poses a global public-health challenge. Nucleic acid amplification testing (NAAT) enables early detection of pandemic viruses and plays a vital role in preventing onward transmission. However, the requirement of skilled operators, expensive instrumentation, and biosafety laboratories has hindered the use of NAAT for screening and diagnosis of suspected patients. Here we report development of a fully automated centrifugal microfluidic system with sample-in-answer-out capability for sensitive, specific, and rapid viral nucleic acid testing. The release of nucleic acids and the subsequent reverse transcription loop-mediated isothermal amplification (RT-LAMP) were integrated into the reaction units of a microfluidic disc. The whole processing steps such as injection of reagents, fluid actuation by rotation, heating and temperature control, and detection of fluorescence signals were carried out automatically by a customized instrument. We validate the centrifugal microfluidic system using oropharyngeal swab samples spiked with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) armored RNA particles. The estimated limit of detection for armored RNA particles is 2 copies per reaction, the throughput is 21 reactions per disc, and the assay sample-to-answer time is approximately 70 min. This enclosed and automated microfluidic system efficiently avoids viral contamination of aerosol, and can be readily adapted for virus detection outside the diagnostic laboratory. ELECTRONIC SUPPLEMENTARY MATERIAL: Supplementary material is available for this article at 10.1007/s11426-020-9800-6 and is accessible for authorized users.

Bimetallic nanoparticles against multi-drug resistant bacteria.

We discovered two antibacterial bimetallic nanoparticles (AuRh and AuRu NPs), that possess antibacterial activities against multi-drug resistant (MDR) Gram-negative bacteria and can cure wound infections. None of the nanoparticles comprising just one of these metals elements shows any antibiotic activities.

Detection of Circulating Tumor Cells by Fluorescence Microspheres-Mediated Amplification.

Here we describe a fluorescent microspheres-based separation and analysis that enables the isolation of circulating tumor cells (CTCs) from whole blood of patients with metastatic cancer and the identification of isolated CTCs in situ without immunostaining. This approach uses antibody-functionalized fluorescent polystyrene (PS) microspheres that can selectively bind to CTCs. The binding of CTCs and fluorescent PS microspheres leads to the formation of complexes of CTCs and fluorescent PS microspheres, thereby the CTCs are size-amplified and labeled simultaneously. A pyramidal microcavity array (PMCA) is fabricated using microfabrication technology to create a precise microfilter structure with a high aspect ratio. The PMCA filter device can effectively isolate microspheres-labeled CTCs, while allow hematologic cells to deform and pass through. Using this approach, CTCs are isolated and identified in 15 of 18 patients with metastatic colorectal cancer. This approach will open new possibilities for CTCs isolation and identification and can serve a versatile platform to facilitate CTCs analysis in diverse biomedical applications.

Thermophoretic Detection of Exosomal microRNAs by Nanoflares.

Exosomal microRNAs (miRNAs) are reliable and noninvasive biomarkers for the early diagnosis of cancer. Yet, accurate and feasible detection of exosomal miRNAs is often hampered by the low abundance of miRNAs in exosomes and the requirement for RNA extraction in large sample volumes. Here we show a thermophoretic sensor implemented with nanoflares for in situ detection of exosomal miRNAs, without resorting to either RNA extraction or target amplification. Thermophoretic accumulation of nanoflare-treated exosomes leads to an amplified fluorescence signal upon the binding of exosomal miRNAs to nanoflares, allowing for direct and quantitative measurement of exosomal miRNAs down to 0.36 fM in 0.5 µL serum samples. One of the best markers, exosomal miR-375, showed an accuracy of 85% for detection of estrogen receptor-positive breast cancer at early stages (stages I, II). This work provides a feasible tool to improve the diagnosis of cancer.

A liquid metal composite by ZIF-8 encapsulation.

A new composite material positioning a liquid metal core within a zeolitic imidazolate framework shell is developed. The core-shell interactions along with the structure/properties of the composite material can be easily regulated by the ligand/metal ion ratio. Enhanced photothermal conversion of the liquid metal core is achieved after ZIF-8 encapsulation.

Microfluidics-Based Biomaterials and Biodevices.

The rapid development of microfluidics technology has promoted new innovations in materials science, particularly by interacting with biological systems, based on precise manipulation of fluids and cells within microscale confinements. This article reviews the latest advances in microfluidics-based biomaterials and biodevices, highlighting some burgeoning areas such as functional biomaterials, cell manipulations, and flexible biodevices. These areas are interconnected not only in their basic principles, in that they all employ microfluidics to control the makeup and morphology of materials, but also unify at the ultimate goals in human healthcare. The challenges and future development trends in biological application are also presented.

A Self-Contained Chemiluminescent Lateral Flow Assay for Point-of-Care Testing.

Immunoassays whose readouts rely on chemiluminescence are increasingly useful for a broad range of analytical applications, but they are rarely made into point-of-care (POC) format because of the complex reagents required (some reagents have to be stored in low temperatures, and some reagents have to be freshly made right before the assay). This study reports a self-contained chemiluminescent lateral flow assay (CLFA), which prestores all necessary reagents. This CLFA contains three parts: the normal lateral flow assay (LFA) strip, the chemiluminescence substrate pad, and the polycarbonate (PC) holder. On the LFA strip, we simultaneously labeled horseradish peroxidase (HRP) and antibody on the gold nanoparticles (AuNPs) for the conjugate pad. For the substrate pad, we used sodium perborate as the oxidant and lyophilized the chemiluminescence substrate on the glass fiber, which allows long-term storage. After the transfer of substrate from the substrate pad to the nitrocellulose (NC) membrane, we captured the chemiluminescence signal for the quantification of the targets. The HRP on the AuNPs can amplify the chemiluminescence signal efficiently. We used this CLFA system to detect both macromolecules and small molecules successfully. This self-contained and easily processable device is exceedingly appropriate for rapid detection and is a convenient platform for POC testing.

An automated and portable microfluidic chemiluminescence immunoassay for quantitative detection of biomarkers.

Microfluidic platforms capable of automated, rapid, sensitive, and quantitative detection of biomarkers from patient samples could make a major impact on clinical or point-of-care (POC) diagnosis. In this work, we realize an automated diagnostic platform composed of two main components: (1) a disposable, self-contained, and integrated microfluidic chip and (2) a portable instrument that carries out completely automated operations. To demonstrate its potential for real-world application, we use injection molding for mass fabrication of the main components of disposable microfluidic chips. The assembled three-layered chip with on-chip mechanical valves for fluid control consists of (1) a top silicone fluidic layer with embedded zigzag microchannels, reagent reservoirs and a negative pressure port, (2) a middle tinfoil layer with patterned antibody/antigen stripes, and (3) a bottom silicone substrate layer with waste reservoirs. The versatility of the microfluidics-based system is demonstrated by implementation of a chemiluminescence immunoassay for quantitative detection of C-reactive protein (CRP) and testosterone in real clinical samples. This lab-on-a-chip platform with features of quantitation, portability and automation provides a promising strategy for POC diagnosis.

High-Performance Electrochemical Catalysts Based on Three-Dimensional Porous Architecture with Conductive Interconnected Networks.

The electrochemical applications of traditional carbon nanomaterials such as carbon nanotubes (CNTs) and graphene (G) powders are significantly impeded by their poor three-dimensional (3D) conductivity and lack of hierarchical porous structure. Here, we have constructed a 3D highly conductive CNTs networks and further combined it with mesoporous carbon (mC) for the creation of a core-shell structured (CNT@mC) composite sponge that featured 3D conductivity and hierarchical porous structure. In the composite sponge, interconnected CNTs efficiently eliminates the contact resistance and the hierarchical pores significantly facilitate the mass transport. The electron transfer rates, electroactive surface area and catalytic activity of the CNT@mC composite sponge based catalysts were tested in the direct methanol fuel cells (DMFCs) and electrochemical sensors. In DMFCs, the Pd nanoparticles deposited CNT@mC showed significantly improved catalytic activity and methanol oxidization current. As for amperometric sensing of endocrine disrupting compounds (EDCs), CNT@mC-based catalyst gave a liner range from 10 nM to 1 mM for bisphenol A (BPA) detection and showed great promise for simultaneous detection of multiple EDCs. BPA recovery from environmental water further indicated the potential practical applications of the sensor for BPA detection. Finally, the electrochemical performance of CNT@mC were also investigated in impedimetric sensors. Good selectivity was obtained in impedimetric sensing of BPA and the detection limit was measured to be 0.3 nM. This study highlighted the exceptional electrochemical properties of the CNT@mC composite sponge enabled by its 3D conductivity and hierarchical porous structure. The strategy described may further pave a way for the creation of novel functional materials through integrating multiple superior properties into a single nanostructure for future clean energy technologies and environmental monitoring systems.