Touchable cell biophysics property recognition platforms enable multifunctional blood smart health care

A Miniature Modular Fluorescence Flow Cytometry System

Fluorescence flow cytometry is a powerful instrument to distinguish cells or particles labelled with high-specificity fluorophores. However, traditional flow cytometry is complex, bulky, and inconvenient for users to adjust fluorescence channels. In this paper, we present a modular fluorescence flow cytometry (M-FCM) system in which fluorescence channels can be flexibly arranged. Modules for particle focusing and fluorescence detection were developed. After hydrodynamical focusing, the cells were measured in the detection modules, which were integrated with in situ illumination and fluorescence detection. The signal-to-noise ratio of the detection reached to 33.2 dB. The crosstalk among the fluorescence channels was eliminated. The M-FCM system was applied to evaluate cell viability in drug screening, agreeing well with the commercial cytometry. The modular cytometry presents several outstanding features: flexibility in setting fluorescence channels, cost efficiency, compact construction, ease of operation, and the potential to upgrade for multifunctional measurements. The modular cytometry provides a multifunctional platform for various biophysical measurements, e.g., electrical impedance and refractive-index detection. The proposed work paves an innovative avenue for the multivariate analysis of cellular characteristics.

Gradient Hydrogels Spatially Trapped Optical Cell Profiling for Quantitative Blood Cellular Osmotic Analysis

The quantitative exploration of cellular osmotic responses and a thorough analysis of osmotic pressure-responsive cellular behaviors are poised to offer novel clinical insights into current research. This underscores a paradigm shift in the long-standing approach of colorimetric measurements triggered by red cell lysis. In this study, we engineered a purpose-driven optofluidic platform to facilitate the goal. Specifically, creating photocurable hydrogel traps surmounts a persistent challenge─optical signal interference from fluid disturbances. This achievement ensures a stable spatial phase of cells and the acquisition of optical signals for accurate osmotic response analysis at the single-cell level. Leveraging a multigradient microfluidic system, we constructed gradient osmotic hydrogel traps and developed an imaging recognition algorithm, empowering comprehensive analysis of cellular behaviors. Notably, this system has successfully and precisely analyzed individual and clustered cellular responses within the osmotic dimension. Prospective clinical testing has further substantiated its feasibility and performance in that it demonstrates an accuracy of 92% in discriminating complete hemolysis values (n = 25) and 100% in identifying initial hemolysis values (n = 25). Foreseeably, this strategy should promise to advance osmotic pressure-related cellular response analysis, benefiting further investigation and diagnosis of related blood diseases, blood quality, drug development, etc.

Confinement-enhanced microalgal individuals biosensing for digital atrazine assay

Microalgal sensors are widely recognized for their high sensitivity, accessibility, and low cost. However, the current dilemma of motion-induced spatial phase changes and concentration-related multiple scattering interferes with induced test instability and limited sensitivity, which has hindered their practical applications. Here, a differentiated strategy, named confinement-enhanced microalgal biosensing (C-EMB), is developed and proposed to pave the way. The in-situ printed microgel trap is designed to confine Chlamydomonas reinhardtii individuals, stabilizing their spatial phase. The microgel trap arrays are introduced to eliminate the multiple scattering of microalgae, breaking the existing effective concentration in traditional microalgal sensing and enabling sensitive assays. The integration with lab-on-a-chip technology and a developed digital imaging algorithm empower portable and automated detection. With this system, a microalgae analyzer is developed for atrazine detection, featuring a linear range of 0.04-100 μg/L. We assess the system's performance through practical atrazine assays on commercial food, using a double-blind test against a standard instrument. Our results demonstrate the good accuracy and test stability of this system with the mean bias atrazine detection in corn and sugarcane juice samples (SD) were 1.661 μg/L (3.122 μg/L) and 3.144 μg/L (4.125 μg/L), respectively. This method provides a new paradigm of microalgal sensors and should advance the further applications of microalgal sensors in commercial and practical settings.

A microfluidic hemostatic diagnostics platform: Harnessing coagulation-induced adaptive-bubble behavioral perception

Clinical viscoelastic hemostatic assays, which have been used for decades, rely on measuring biomechanical responses to physical stimuli but face challenges related to high device and test cost, limited portability, and limited scalability.. Here, we report a differential pattern using self-induced adaptive-bubble behavioral perception to refresh it. The adaptive behaviors of bubble deformation during coagulation precisely describe the transformation of viscoelastic hemostatic properties, being free of the precise and complex physical devices. And the integrated bubble array chip allows microassays and enables multi-bubble tests with good reproducibility. Recognition of the developed bubble behaviors empowers automated and user-friendly diagnosis. In a prospective clinical study (clinical model development [n = 273]; clinical assay [n = 44]), we show that the diagnostic accuracies were 99.1% for key viscoelastic hemostatic assay indicators (reaction time [R], kinetics time [K], alpha angle [Angle], maximum amplitude [MA], lysis at 30 min [LY30]; n = 220) and 100% (n = 44) for hypercoagulation, healthy, and hypocoagulation diagnoses. This should provide fresh insight into existing paradigms and help more clinical needs.

Valve-Adjustable Optofluidic Bio-Imaging Platform for Progressive Stenosis Investigation

The clinical evidence has proven that valvular stenosis is closely related to many vascular diseases, which attracts great academic attention to the corresponding pathological mechanisms. The investigation is expected to benefit from the further development of an in vitro model that is tunable for bio-mimicking progressive valvular stenosis and enables accurate optical recognition in complex blood flow. Here, we develop a valve-adjustable optofluidic bio-imaging recognition platform to fulfill it. Specifically, the bionic valve was designed with in situ soft membrane, and the internal air-pressure chamber could be regulated from the inside out to bio-mimic progressive valvular stenosis. The developed imaging algorithm enhances the recognition of optical details in blood flow imaging and allows for quantitative analysis. In a prospective clinical study, we examined the effect of progressive valvular stenosis on hemodynamics within the typical physiological range of veins by this way, where the inhomogeneity and local enhancement effect in the altered blood flow field were precisely described and the optical differences were quantified. The effectiveness and consistency of the results were further validated through statistical analysis. In addition, we tested it on fluorescence and noticed its good performance in fluorescent tracing of the clotting process. In virtue of theses merits, this system should be able to contribute to mechanism investigation, pharmaceutical development, and therapeutics of valvular stenosis-related diseases.

Magnetically Actuated Hydrogel Stamping-Assisted Cellular Mechanical Analyzer for Stored Blood Quality Detection

Cellular mechanical property analysis reflecting the physiological and pathological states of cells plays a crucial role in assessing the quality of stored blood. However, its complex equipment needs, operation difficulty, and clogging issues hinder automated and rapid biomechanical testing. Here, we propose a promising biosensor assisted by magnetically actuated hydrogel stamping to fulfill it. The flexible magnetic actuator triggers the collective deformation of multiple cells in the light-cured hydrogel, and it allows for on-demand bioforce stimulation with the advantages of portability, cost-effectiveness, and simplicity of operation. The magnetically manipulated cell deformation processes are captured by the integrated miniaturized optical imaging system, and the cellular mechanical property parameters are extracted from the captured images for real-time analysis and intelligent sensing. In this work, 30 clinical blood samples with different storage durations (<14 days and >14 days) were tested. A deviation of 3.3% in the differentiation of blood storage durations by this system compared to physician annotation demonstrated its feasibility. This system should broaden the application of cellular mechanical assays in diverse clinical settings.

Convenient tumor 3D spheroid arrays manufacturing via acoustic excited bubbles for in situ drug screening

The quick and convenient fabrication of in vitro tumor spheroids models has been pursued for clinical drug discovery and personalized therapy. Here, uniform three-dimensional (3D) tumor spheroids are quickly constructed by acoustically excited bubble arrays in a microfluidic chip and performed drug response testing in situ. In detail, bubble oscillation excited by acoustic waves induces second radiation force, resulting in the cells rotating and aggregating into tumor spheroids, which obtain controllable sizes ranging from 30 to 300 μm. These spherical tumor models are located in microfluidic networks, where drug solutions with gradient concentrations are generated from 0 to 18 mg mL^-1, so that the cell spheroids response to drugs can be monitored conveniently and efficiently. This one-step tumor spheroids manufacturing method significantly reduces the model construction time to less than 15 s and increases efficiency by eliminating additional transfer processes. These significant advantages of convenience and high-throughput manufacturing make the tumor models promising for use in tumor treatment and point-of-care diagnosis.

Design and Fabrication of a Fully-Integrated, Miniaturised Fluidic System for the Analysis of Enzyme Kinetics

The lab-on-a-chip concept, enabled by microfluidic technology, promises the integration of multiple discrete laboratory techniques into a miniaturised system. Research into microfluidics has generally focused on the development of individual elements of the total system (often with relatively limited functionality), without full consideration for integration into a complete fully optimised and miniaturised system. Typically, the operation of many of the reported lab-on-a-chip devices is dependent on the support of a laboratory framework. In this paper, a demonstrator platform for routine laboratory analysis is designed and built, which fully integrates a number of technologies into a single device with multiple domains such as fluidics, electronics, pneumatics, hydraulics, and photonics. This facilitates the delivery of breakthroughs in research, by incorporating all physical requirements into a single device. To highlight this proposed approach, this demonstrator microsystem acts as a fully integrated biochemical assay reaction system. The resulting design determines enzyme kinetics in an automated process and combines reservoirs, three-dimensional fluidic channels, optical sensing, and electronics in a low-cost, low-power and portable package.

Portable Prussian Blue-Based Sensor for Bacterial Detection in Urine

Bacterial infections can affect the skin, lungs, blood, and brain, and are among the leading causes of mortality globally. Early infection detection is critical in diagnosis and treatment but is a time- and work-consuming process taking several days, creating a hitherto unmet need to develop simple, rapid, and accurate methods for bacterial detection at the point of care. The most frequent type of bacterial infection is infection of the urinary tract. Here, we present a wireless-enabled, portable, potentiometric sensor for E. coli. E. coli was chosen as a model bacterium since it is the most common cause of urinary tract infections. The sensing principle is based on reduction of Prussian blue by the metabolic activity of the bacteria, detected by monitoring the potential of the sensor, transferring the sensor signal via Bluetooth, and recording the output on a laptop or a mobile phone. In sensing of bacteria in an artificial urine medium, E. coli was detected in ~4 h (237 ± 19 min; n = 4) and in less than 0.5 h (21 ± 7 min, n = 3) using initial E. coli concentrations of ~10³ and 10⁵ cells mL^-1, respectively, which is under or on the limit for classification of a urinary tract infection. Detection of E. coli was also demonstrated in authentic urine samples with bacteria concentration as low as 10⁴ cells mL^-1, with a similar response recorded between urine samples collected from different volunteers as well as from morning and afternoon urine samples.

Space-time-regulated imaging analyzer for smart coagulation diagnosis

The development of intelligent blood coagulation diagnoses is awaited to meet the current need for large clinical time-sensitive caseloads due to its efficient and automated diagnoses. Herein, a method is reported and validated to realize it through artificial intelligence (AI)-assisted optical clotting biophysics (OCB) properties identification. The image differential calculation is used for precise acquisition of OCB properties with elimination of initial differences, and the strategy of space-time regulation allows on-demand space time OCB properties identification and enables diverse blood function diagnoses. The integrated applications of smartphones and cloud computing offer a user-friendly automated analysis for accurate and convenient diagnoses. The prospective assays of clinical cases (n = 41) show that the system realizes 97.6%, 95.1%, and 100% accuracy for coagulation factors, fibrinogen function, and comprehensive blood coagulation diagnoses, respectively. This method should enable more low-cost and convenient diagnoses and provide a path for potential diagnostic-markers finding.

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An ultraportable optofluidic analyzer empowers convenient coagulation diagnoses

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The system enables optical clotting biophysics (OCB) properties acquisition and process

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Coagulation function diagnoses uses intelligent OCB properties identification

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Space-time regulation of OCB properties endow it capability to diverse diagnoses

Hydrogel Stamping for Rapid, Multiplexed, Point-of-Care Immunostaining of Cells and Tissues

In the era of precision oncology, multicolor fluorescence imaging has become a core technology for multiplexed molecular analysis of cellular and tissue specimens. However, conventional solution-based staining is labor-intensive and time-consuming and requires considerable expertise to yield optimal results, which creates difficulties for employing this technology in resource-limited settings. Here, we report a new immunostaining method based on hydrogel stamping, which is simple, fast, easy to use, and reproducible. We showed that a hydrophilic hydrogel stamp could effectively transfer fluorescent antibodies to targets and withdraw an excess solution when the reaction is completed, obviating the need for extra washing. This unique property allows for quality immunostaining in 5 min for cells using one-eighth of antibody consumption compared to the conventional solution-based method. Furthermore, we implemented fluorescence quenching and immunocycling with hydrogel staining for multiplexed analysis of 9 protein markers at a single cell level. Finally, we applied the immunocycling method to human breast cancer tissue samples and showed quality immunostaining over a large area (∼2 cm²) in 30 min for molecular subtyping of breast cancer. The hydrogel immunostaining could open new opportunities for rapid, automated, and multiplexed profiling in compact point-of-care systems for molecular cancer diagnosis.

Microfluidic-based in vitro thrombosis model for studying microplastics toxicity

The potential impact of microplastics (MPs) on health has caused great concern, and a toxicology platform that realistically reproduces the system behaviour is urgently needed to further explore and validate MP-related health issues. Herein, we introduce an optically assisted thrombus platform to reveal the interaction of MPs with the vascular system. The risk of accumulation has also been evaluated using a mouse model, and the effect of MPs on the properties of the thrombus are validated via in vitro experiments. The microfluidic system is endothelialized, and the regional tissue injury-induced thrombosis is then realized through optical irradiation. Whole blood is perfused with MPs, and the invasion process visualized and recorded. The mouse model shows a cumulative risk in the blood with continuous exposure to MPs (P-value < 0.0001). The on-chip results show that MP invasion leads to decreased binding of fibrin to platelets (P-value < 0.0001), which is consistent with the results of the in vitro experiments, and shows a high risk of thrombus shedding in real blood flow compared with normal thrombus. This work provides a new method to further reveal MP-related health risks.