Label-free high-throughput impedance-activated cell sorting.

Cell sorting holds broad applications in fields such as early cancer diagnosis, cell differentiation studies, drug screening, and single-cell sequencing. However, achieving high-throughput and high-purity in label-free single-cell sorting is challenging. To overcome this issue, we propose a label-free, high-throughput, and high-accuracy impedance-activated cell sorting system based on impedance detection and dual membrane pumps. Leveraging the low-latency characteristics of FPGA, the system facilitates real-time dual-frequency single-cell impedance detection with high-throughput (5 × 104 cells per s) for HeLa, MDA-MB-231, and Jurkat cells. Furthermore, the system accomplishes low-latency (less than 0.3 ms), label-free, high-throughput (1000 particles per s) and high-accuracy (almost 99%) single-particle sorting using FPGA-based high-precision sort-timing prediction. In experiments with Jurkat and MDA-MB-231 cells, the system achieved a throughput of up to 1000 cells per s, maintaining a pre-sorting purity of 28.57% and increasing post-sorting purity to 97.09%. These findings indicate that our system holds significant potential for applications in label-free, high-throughput cell sorting.

Fabrication of Flexible and Re-entrant Liquid-Superrepellent Surface Using Proximity and PNIPAM-Assisted Soft Lithography.

The nature-inspired flexible and re-entrant liquid-superrepellent surface has attracted significant attention due to its excellent superomniphobic performance against low-surface-tension liquids. Although conventional photolithography and molding methods offer the advantage of large-area manufacturing, they often involve multiple double-sided alignment and exposure steps, resulting in complex procedures with long processing cycles. In this study, we proposed a straightforward single-exposure ultraviolet proximity lithography method for re-entrant liquid-superrepellent surface fabrication using a photomask with a coaxial circular aperture and ring. A theoretical calculation model for the three-dimensional light intensity distribution in proximity lithography was developed for the prediction of feature sizes for both singly and doubly re-entrant microstructures. Soft lithography techniques, which rely on surface modification and the modulation of the transfer material's flexibility, efficiently optimized the fabrication of flexible re-entrant molds and patterns. By incorporating nanoclay-modified poly(N-isopropylacrylamide) (PNIPAM) into the molding process, we fabricated a three-layer hierarchical structure featuring micrometer-scale wrinkles, re-entrant microstructures, and nanoscale fluorinated silica particles, significantly enhancing the surface's robustness and pressure resistance. The resulting large-area flexible and re-entrant liquid-superrepellent surface demonstrated excellent superomniphobic self-cleaning performance and satisfactory optical transparency, as evidenced by reflection and transmission experiments, showcasing its potential applications in self-cleaning, membrane distillation, and digital microfluidics.

Label-free active single-cell encapsulation enabled by microvalve-based on-demand droplet generation and real-time image processing.

Droplet microfluidics-based single-cell encapsulation is a critical technology that enables large-scale parallel single-cell analysis by capturing and processing thousands of individual cells. As the efficiency of passive single-cell encapsulation is limited by Poisson distribution, active single-cell encapsulation has been developed to theoretically ensure that each droplet contains one cell. However, existing active single-cell encapsulation technologies still face issues related to fluorescence labeling and low throughput. Here, we present an active single-cell encapsulation technique by using microvalve-based drop-on-demand technology and real-time image processing to encapsulate single cells with high throughput in a label-free manner. Our experiments demonstrated that the single-cell encapsulation system can encapsulate individual polystyrene beads with 96.3 % efficiency and HeLa cells with 94.9 % efficiency. The flow speed of cells in this system can reach 150 mm/s, resulting in a corresponding theoretical encapsulation throughput of 150 Hz. This technology has significant potential in various biomedical applications, including single-cell omics, secretion detection, and drug screening.

Prognostic Factors in Philadelphia Chromosome-Positive Acute Myeloid Leukemia Using Fluorescence in Situ Hybridization.

BACKGROUND: Philadelphia chromosome-positive acute myeloid leukemia (Ph+ AML) is a rare leukemia subtype first classified by the World Health Organization in 2016. The incidence of Ph+ AML is approximately 0.5 - 3%, and its prognosis is poor. Ph+ AML with additional chromosomal abnormalities in children has rarely been reported, and its treatment and prognosis remain uncertain. METHODS: We retrospectively analyzed 649 patients with AML from 2006 - 2021. Six (0.9%) patients with Ph+ AML were identified and treated with conventional chemotherapy. The clinical features and prognoses were retrospectively analyzed. RESULTS: Six cases of AML with a Ph chromosome were reported. One of the six individuals exhibited a biphenotypic immunophenotype, one exhibited a simple myeloid immunophenotype, and the other four exhibited myeloid and lymphoid expression. Karyotypic analysis (R banding) was performed in six cases, four of which were classical Ph chromosomal abnormalities, two of which had additional abnormalities outside the Ph chromosome. Fluorescence in situ hybridization (FISH) analysis using the BCR/ABL fusion gene distinguished that the BCR major breakpoint break in three cases was type P210 and the BCR minor breakpoint break in three cases was type P190. The complete remission rate of the six patients in this study using conventional chemotherapy was 60%, with a median survival time of 7.5 months. CONCLUSIONS: In summary, Ph+ AML is a heterogeneous disease often associated with additional chromosomal abnormalities. Ph+ AML is seen with a lymphoid immunophenotype and alterations in associated genes such as the IGH gene. Adults were predominantly P210 and two cases in children were both P190. Conventional treatments are less effective, and there are no standard treatment regimens.

Diagnostic value of random urine protein/creatinine ratio for preeclampsia.

Objective: The 24-h urine protein remains the gold standard to diagnose proteinuria in suspected preeclamptic patients. However, this test is time consuming and sometimes inaccurate. In this study, we aimed to analyse the correlation between the random urine protein/creatinine ratio (UPCR) and 24-h urine protein and to explore the clinical value of UPCR in the diagnosis of preeclampsia. Method: We retrospectively evaluated 109 pregnant women from our hospital who had hypertensive diseases. They were grouped according to time of urine collection and disease severity to compare differences in random urine protein, urine creatinine, and UPCR. The correlation between the UPCR and 24-h urine protein was determined by Pearson's linear correlation. Results: We found no statistically significant differences in random urine protein, urine creatinine, or UPCR among the four time of sampling groups. Further, random urine protein, UPCR, and 24-h urine protein between the gestational hypertension and preeclampsia groups differed significantly (P < 0.001). Correlation analysis showed significant positive correlation between random urine protein, and 24-h urine protein, and UPCR and 24-h urine protein, with r values of 0.789 and 0.810, respectively. According to the receiver operating characteristic (ROC) curve, the optimal threshold, sensitivity, specificity, and area under the curve of UPCR for the diagnosis of preeclampsia were 0.456 g/mmol, 67.8 %, 78.3 %, and 0.747, respectively (95 % confidence interval [CI], 0.65-0.844). Conclusion: This study indicated that UPCR is significantly correlated with 24-h urine protein and is expected to replace the 24-h urine protein test as a diagnostic indicator of preeclampsia.

A high-precision automated liquid pipetting device with an interchangeable tip.

Liquid handling is a necessary act to deal with liquid samples from scientific labs to industry. However, existing pipetting devices suffer from inaccuracy and low precision when dealing with submicroliter liquids, which significantly affect their applications in low-volume quantitation. In this article, we present an automated liquid pipetting device that can aspirate liquid from microplates and dispense nanoliter droplets with high precision. Liquid aspiration is realized by using a micropump and a solenoid valve, and on-demand nanoliter droplet printing is realized by using a low-cost and interchangeable pipette tip combined with a piezoelectric actuator. Based on the microfluidic printing technology, the volumetric coefficient of variation of the dispensed liquid is less than 2% below 1 µl. A demonstration of concentration dilution for quantitative analysis has been successfully performed using the automated liquid pipetting device, demonstrating its potential in low-volume liquid handling for a wide range of biomedical applications.

Droplet Printing Enabled by Cavity Collapse Ejection.

The behavior of cavity collapse in liquids is of fundamental importance in natural and industrial applications. It is still challenging to use the phenomenon of cavity collapse ejection in on-demand droplet printing technology. In this study, we investigate the cavity collapse ejection phenomenon in the submillimeter to millimeter scale and demonstrate that the cavity capillary energy is a critical factor affecting the state of the generated jet. Based on this phenomenon, we developed a droplet printing technology that can print nanoliter satellite-free droplets from a millimeter-sized nozzle, which reduces the risk of nozzle clogging. Using this printing technology, we demonstrated the printing of a nanoparticle suspension with 60% mass loading. Finally, we also showcased the printing of various inks for different applications using this technology, demonstrating the printability of cavity collapse-ejection printing technology in functional inks and showing potential to be applied in scenarios such as bioassays, the electronics industry, and additive manufacturing.

Real-time fluorescence imaging flow cytometry enabled by motion deblurring and deep learning algorithms.

Fluorescence imaging flow cytometry (IFC) has been demonstrated as a crucial biomedical technique for analyzing specific cell subpopulations from heterogeneous cellular populations. However, the high-speed flow of fluorescent cells leads to motion blur in cell images, making it challenging to identify cell types from the raw images. In this study, we present a real-time single-cell imaging and classification system based on a fluorescence microscope and deep learning algorithm, which is able to directly identify cell types from motion-blur images. To obtain annotated datasets of blurred images for deep learning model training, we developed a motion deblurring algorithm for the reconstruction of blur-free images. To demonstrate the ability of this system, deblurred images of HeLa cells with various fluorescent labels and HeLa cells at different cell cycle stages were acquired. The trained ResNet achieved a high accuracy of 96.6% for single-cell classification of HeLa cells in three different mitotic stages, with a short processing time of only 2 ms. This technology provides a simple way to realize single-cell fluorescence IFC and real-time cell classification, offering significant potential in various biological and medical applications.

Application of Air-Coupled Ground Penetrating Radar Based on F-K Filtering and BP Migration in High-Speed Railway Tunnel Detection.

As the number and length of high-speed railway tunnels increase in China, implicit defects such as insufficient lining thicknesses, voids, and poor compaction have become increasingly common, posing a serious threat to train operation safety. It is, therefore, imperative to conduct a comprehensive census of the defects within the tunnel linings. In response to this problem, this study proposes a high-speed railway tunnel detection method based on vehicle-mounted air-coupled GPR. Building on a forward simulation of air-coupled GPR, the study proposes the F-K filtering and BP migration algorithms based on the practical considerations of random noise and imaging interference from the inherent equipment. Through multi-dimensional quantitative comparisons, these algorithms are shown to improve the spectrum entropy values and instantaneous amplitude ratios by 4.6% and 11.6%; and 120% and 180%, respectively, over the mean and bandpass filtering algorithms, demonstrating their ability to suppress clutter and enhance the internal signal prominence of the lining. The experimental results are consistent with the forward simulation trends, and the verification using the ground-coupled GPR detection confirms that air-coupled GPR can meet the requirements of high-speed railway tunnel lining inspections. A comprehensive GPR detection model is proposed to lay the foundation for a subsequent defect census of high-speed railway tunnels.

Additional endoscopic treatments for patients with positive lateral margins after endoscopic resection of early esophageal squamous cell carcinoma.

There are currently no well-established treatment strategies for early esophageal squamous cell carcinoma (ESCC) for patients with only positive lateral margin (LM+) following endoscopic resection (ER). The present study aimed to find a treatment strategy for patients with early ESCC with non-curative resection (non-CR) and only LM+ following ER. In total, 511 patients with early ESCC treated at the Fourth Hospital of Hebei Medical University (Shijiazhuang, China) with ER were retrospectively analyzed, 41 of which (8%) were patients with only LM+ after non-CR. Of these, 28 patients received re-ER and 13 received additional surgical treatment. The clinicopathological characteristics of patients were analyzed and those who underwent additional surgery vs. re-ER were compared. Residual cancer cells were found in 27 patients (27/41, 65.9%) following re-ER or additional surgery. A significant increase in residual cancer cells was observed in patients with poorly differentiated cancer and patients with multiple LM+ (P=0.03 and P=0.015, respectively). Older patients and patients with single LM+ tended to choose re-ER (P=0.023 and P=0.038, respectively). In addition, there were three cases (3/13, 23.1%) of lymph node metastasis in the additional surgery group. However, within the limited follow-up time (mean, 36.1±24.1 months), no recurrence or metastasis was found in the remaining patients. The results showed that re-ER may be a more suitable additional therapy compared with surgery for patients with LM+ following non-CR, at least in the medium-term.

Highly Uniform Droplet Generation Enabled by Microfluidic Impact Printing and Its Application in Lyophilized Microbeads Preparation.

GOAL: Research on droplet generation technology with a large volume range and high uniformity has great significance in biomedical engineering. METHODS: We explored the influence of both the liquid level height in the reservoir and the flow resistance distribution on the droplet volumes besides the nozzle size for the microfluidic impact printing (MIP) method. Finally, this droplet generation technology is applied to the preparation of lyophilized microbeads with high uniformity in volume. RESULTS: The coefficient of variation (CV) of the droplet volumes can be down to 0.55%. By adjusting the flow resistance distribution of the microchannels and the nozzle size, the droplet volume generated by the MIP system ranges from 0.4 nL to 610 nL. CONCLUSION: On-demand droplet generation with high uniformity in the range of subnanoliter to submicroliter is achieved. Furthermore, this droplet generation technology is successfully applied to the preparation of highly uniform lyophilized microbeads. SIGNIFICANCE: This large volumetric range and highly uniform droplet generation technology has tremendous application potential in fields such as digital PCR detection, pharmaceutic preparation, and the construction of concentration arrays. Furthermore, it can also be used as a high-precision liquid distribution method for processing liquid in a submicroliter.

An Improved Q-Learning-Based Sensor-Scheduling Algorithm for Multi-Target Tracking.

Target tracking is an essential issue in wireless sensor networks (WSNs). Compared with single-target tracking, how to guarantee the performance of multi-target tracking is more challenging because the system needs to balance the tracking resource for each target according to different target properties and network status. However, the balance of tracking task allocation is rarely considered in those prior sensor-scheduling algorithms, which may result in the degradation of tracking accuracy for some targets and additional system energy consumption. To address this issue, we propose in this paper an improved Q-learning-based sensor-scheduling algorithm for multi-target tracking (MTT-SS). First, we devise an entropy weight method (EWM)-based strategy to evaluate the priority of targets being tracked according to target properties and network status. Moreover, we develop a Q-learning-based task allocation mechanism to obtain a balanced resource scheduling result in multi-target-tracking scenarios. Simulation results demonstrate that our proposed algorithm can obtain a significant enhancement in terms of tracking accuracy and energy efficiency compared with the existing sensor-scheduling algorithms.

An Energy-Efficient Clustering Method for Target Tracking Based on Tracking Anchors in Wireless Sensor Networks.

As a key technology in wireless sensor networks (WSNs), target tracking plays an essential role in many applications. To improve energy efficiency, clustering is widely used in tracking to organize the network to achieve data fusion and reduce communication costs. Many existing studies make dynamic adjustments based on static clusters to track moving targets. However, the additional overhead caused by frequent cluster reconstruction and redundant data transmission is rarely considered. To address this issue, we propose a tracking-anchor-based clustering method (TACM) in this paper, in which tracking anchors are introduced to provide activation indications for sensors according to the target position. We use the rough fuzzy C-means (RFCM) algorithm to locate the anchors and use the membership table to activate sensors to form a cluster. Since there are no sending, receiving, and fusing data tasks for anchors, they are lightly burdened and can significantly reduce the frequency of being rotated. Moreover, the state of cluster members (CMs) is scheduled using the linear 0-1 programming to reduce redundant transmissions. The simulation results demonstrate that, compared with some existing clustering methods, the proposed TACM effectively reduces the energy consumption when tracking a moving target, thus prolonging the network lifetime.

Associated risk factor analysis and the prognostic impact of positive resection margins after endoscopic resection in early esophageal squamous cell carcinoma.

Endoscopic resection for early esophageal cancer has a risk of residual margins. The risk these residual margins pose have not been fully evaluated. The present study aimed to investigate the associated risk factors and prognosis of residual margins following the endoscopic resection of early esophageal squamous cell carcinoma. In total, 369 patients (381 lesions) with early esophageal squamous cell carcinoma treated in the Fourth Hospital of Hebei Medical University (Shijiazhuang, China) with endoscopic resection were retrospectively analyzed. Sex, age, location, tumor diameter, depth of tumor invasion, endoscopic treatment, endoscopic ultrasonography (EUS) before resection, work experience of endoscopists and the degree of tumor differentiation were all evaluated as potential risk factors. In addition, the prognosis of patients with positive margins were analyzed. A total of 73 patients (73/381, 19.2%) had positive margins after endoscopic resection. Amongst the 65 patients who were successfully followed up, five patients succumbed to cardiovascular and cerebrovascular diseases, one patient received radiotherapy, two patients received radiotherapy and chemotherapy whilst one patient received chemotherapy. By contrast, 12 patients received surgery and 20 patients received additional endoscopic mucosal resection or endoscopic submucosal dissection. The other 29 patients were followed up regularly and no recurrence could be found. Univariate analysis revealed that tumor diameter, endoscopic treatment, depth of invasion, EUS before resection, degree of tumor differentiation and direction of invasion were all associated with the positive margin. Multivariate logistic regression analysis then found that EUS before resection, degree of tumor differentiation and depth of tumor invasion are independent risk factors for positive margins after endoscopic resection. These results suggest that poorly differentiated lesions and deeper invasion depth can increase the risk of positive margin after endoscopic resection. As a result, EUS evaluation before resection may reduce the risk of invasion depth. In addition, for poorly differentiated lesions, more aggressive treatment regimens may be recommended for preventing recurrence.

Chemical Speciation and Leaching Behavior of Hazardous Trace Elements in Coal Combustion Products from Coal-Fired Power Stations in China.

This paper reports on the chemical speciation and leaching behavior of a selected group of hazardous trace pollutants in lignite and lignite-petcoke blend co-combustion products from three power stations in China. The evaluation of speciation results showed that, during combustion, oxidizable elements, mainly As and Mo, bound to organic matter and sulfides in coals were mostly transferred to easily water-soluble forms or to slightly acidic states in the ashes. This manner was the most readily bioavailable condition for such an environment. The evaluation of the leaching results shows that the use of petroleum coke as co-fuel has an impact on the ash composition and on the leaching behavior of some inorganic trace pollutants such as Mo and V. The leaching results compared to the European waste acceptance criteria for landfills reveal that the Mo and As' leaching yield brand the coal combustion products as materials that necessitate preventative measures to reduce their potential leaching. Future work will be focused on the application of our novel chemical stabilization method to these coal ashes to reduce the mobility of elements such as Mo and As, and other potentially leachable elements, and on the use of the resulting ash with aggregate products as a substitute for concrete production.

Polymorphisms of Cytochromes P450 and Glutathione S-Transferases Synergistically Modulate Risk for Parkinson's Disease.

Background: Environmental substances such as pesticides are well-known in link with Parkinson's disease (PD) risk. Enzymes including cytochromes P450 (CYPs), esterases and glutathione S-transferases (GSTs) are responsible for the xenobiotic metabolism and may functionally compensate each other for subtypes in the same class. We hypothesize that the genetic effects of each class modulate PD risk stronger in a synergistic way than individually. Methods: We selected 14 polymorphic loci out of 13 genes which encode enzymes in the classes of CYP, esterase, and GST, and recruited a cohort of 1,026 PD and control subjects from eastern China. The genotypes were identified using improved multiplex ligation detection reaction and analyzed using multiple models. Results: A total of 13 polymorphisms remained after Hardy-Weinberg equilibrium analysis. None of the polymorphisms were independently associated with PD risk after Bonferroni correction either by logistic regression or genetic models. In contrast, interaction analyses detected increased resistance to PD risk in individuals carrying the rs12441817/CC (CYP1A1) and rs2070676/GG + GC (CYP2E1) genotypes (P = 0.002, OR = 0.393, 95% CI = 0.216-0.715), or carrying the GSTM1-present, GSTT1-null, rs156697/AG + GG (GSTO2) and rs1695/AA (GSTP1) genotypes (P = 0.003, OR = 0.348, 95% CI = 0.171-0.706). The synergistic effect of GSTs on PD was primarily present in females (P = 0.003). No synergistic effect was observed within genotypes of esterases. Conclusion: We demonstrate a presence of synergistic but not individual impact on PD susceptibility in polymorphisms of CYPs and GSTs. The results indicate that the genetic interplay leads the way to PD development for xenobiotic metabolizing enzymes.

Effect of dietary pattern on pregnant women with gestational diabetes mellitus and its clinical significance.

Gestational diabetes mellitus (GDM) is a common obstetric disease among pregnant women. This study aimed to explore the effect of dietary pattern management to reduce the incidence of GDM. Here, we, retrospectively, analyzed the influence of dietary patterns on the occurrence of GDM and the correlation between dietary patterns and intestinal microbiome distribution and inflammation in pregnant women. Moreover, patients were assigned to the dietary pattern management group and the nondietary pattern management group, and the effects of dietary patterns on the intestinal microbiome distribution and inflammatory factors were investigated. We found that the intestinal microbiome was changed in GDM patients compared with the healthy controls. The relative abundance of probiotics Lactobacillus and Bifidobacterium significantly decreased in patients with GDM. Moreover, compared with the control group, the expression levels of interleukin-6 and tumor necrosis factor-α were significantly increased. Furthermore, dietary pattern management led to intestinal microbiome changes in patients with GDM. In conclusion, dietary pattern management could alleviate GDM via affecting the intestinal microbiome as well as inflammatory conditions in patients.

Hepatic Steatosis: CT-Based Prevalence in Adults in China and the United States and Associations With Age, Sex, and Body Mass Index.

BACKGROUND. Calibrated CT fat fraction (FFCT) measurements derived from un-enhanced abdominal CT reliably reflect liver fat content, allowing large-scale population-level investigations of steatosis prevalence and associations. OBJECTIVE. The purpose of this study was to compare the prevalence of hepatic steatosis, as assessed by calibrated CT measurements, between population-based Chinese and U.S. cohorts, and to investigate in these populations the relationship of steatosis with age, sex, and body mass index (BMI). METHODS. This retrospective study included 3176 adults (1985 women and 1191 men) from seven Chinese provinces and 8748 adults (4834 women and 3914 men) from a single U.S. medical center, all drawn from previous studies. All participants were at least 40 years old and had undergone unenhanced abdominal CT in previous studies. Liver fat content measurements on CT were cross-calibrated to MRI proton density fat fraction measurements using phantoms and expressed as adjusted FFCT measurements. Mild, moderate, and severe steatosis were defined as adjusted FFCT of 5.0-14.9%, 15.0-24.9%, and 25.0% or more, respectively. The two cohorts were compared. RESULTS. In the Chinese and U.S. cohorts, the median adjusted FFCT for women was 4.7% and 4.8%, respectively, and that for men was 5.8% and 6.2%, respectively. In the Chinese and U.S. cohorts, steatosis prevalence for women was 46.3% and 48.7%, respectively, whereas that for men was 58.9% and 61.9%, respectively. Severe steatosis prevalence was 0.9% and 1.8% for women and 0.2% and 2.6% for men in the Chinese and U.S. cohorts, respectively. Adjusted FFCT did not vary across age decades among women or men in the Chinese cohort, although it increased across age decades among women and men in the U.S. cohort. Adjusted FFCT and BMI exhibited weak correlation (r = 0.312-0.431). Among participants with normal BMI, 36.8% and 38.5% of those in the Chinese and U.S. cohorts, respectively, had mild steatosis, and 3.0% and 1.5% of those in the Chinese and U.S. cohorts, respectively, had moderate or severe steatosis. Among U.S. participants with a BMI of 40.0 or greater, 17.7% had normal liver content. CONCLUSION. Steatosis and severe steatosis had higher prevalence in the U.S. cohort than in the Chinese cohort in both women and men. BMI did not reliably predict steatosis. CLINICAL IMPACT. The findings provide new information on the dependence of hepatic steatosis on age, sex, and BMI.

A low-cost self-dispersing method of droplet array generation enabled by a simple reusable mask for bioanalysis and bioassays.

Discontinuous dewetting is an attractive technique that can produce droplet array of specific volume, geometry and at predefined location on a substrate. Droplet array has great potential in bioanalysis such as high-throughput live cell screening, digital PCR, and drug candidates. Here, we propose a self-dispersing droplet array generation method, which has advantages of low cost, simple operation, and easy large-area production ability. Droplet array of specific volumes was generated on a polymethyl methacrylate (PMMA) substrate using a simple reusable polyimide (PI) adhesive mask. Experiment shows that the generated droplet array can be used to successfully capture single particles which obeys Poisson distribution in a high-throughput manner. Furthermore, a droplet-array sandwiching chip was created based on the self-dispersion method for rapid detection of human serum albumin (HSA) at wide range of 183-11,712 µg/mL with low reagent consumption of 2.2 µL, demonstrating its potential applications in convenient high-throughput bioanalysis and bioassays.

Label-free single-cell isolation enabled by microfluidic impact printing and real-time cellular recognition.

Analysis of cellular components at the single-cell level is important to reveal cellular heterogeneity. However, current technologies to isolate individual cells are either label-based or have low performance. Here, we present a novel technique by integrating real-time cellular recognition and microfluidic impact printing (MIP) to isolate single cells with high efficiency and high throughput in a label-free manner. Specifically, morphological characteristics of polystyrene beads and cells, computed by an efficient image processing algorithm, are utilized as selection criteria to identify target objects. Subsequently, each detected single-cell object in the suspension is ejected from the microfluidic channel by impact force. It has been demonstrated that the single-cell isolating system has the ability to encapsulate polystyrene beads in droplets with an efficiency of 95%, while for HeLa cells, this has been experimentally measured as 90.3%. Single-cell droplet arrays are generated at a throughput of 2 Hz and 96.6% of the cells remain alive after isolation. This technology has significant potential in various emerging applications, including single-cell omics, tissue engineering, and cell-line development.