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Abstract A fundamental objective of genomics is to track variations in gene expression program. While metabolic RNA labeling-based single-cell RNA sequencing offers insights into temporal biological processes, its limited applicability only to in vitro models challenges the study of in vivo gene expression dynamics. Herein, we introduce Dyna-vivo-seq, a strategy that enables time-resolved dynamic transcription profiling in vivo at the single-cell level by examining new and old RNAs. The new RNAs can offer an additional dimension to reveal cellular heterogeneity. Leveraging new RNAs, we discern two distinct high and low metabolic labeling populations among proximal tubular (PT) cells. Furthermore, we identify 90 rapidly responding transcription factors during the acute kidney injury in female mice, highlighting that high metabolic labeling PT cells exhibit heightened susceptibility to injury. Dyna-vivo-seq provides a powerful tool for the characterization of dynamic transcriptome at the single-cell level in living organism and holds great promise for biomedical applications.

Abstract Differential RNA expression is becoming increasingly valuable in evaluating tumor heterogeneity for a better understanding of malignant tumors and guiding personalized therapy. However, traditional techniques for analyzing cellular RNA are mainly focused on determining the absolute level of RNA, which may lead to inaccuracies in understanding tumor heterogeneity, primarily due to i) the subtle differences in certain RNA types that have similar total concentrations and ii) the existence of variations in RNA expression across different samples. Herein, a detachable DNA assembly module is proposed that is capable not only of quantifying the expression level of target RNA but also of innovatively evaluating its proportion within its RNA family population through a sequential assembly and disassembly route. Using the let‐7 family as an experimental model, a significant difference is discovered in let‐7a proportion between normal mammary epithelial cells and breast cancer cells, a characteristic that is often missed in bulk analysis of traditional techniques. By combining concentration and proportion information, the detachable DNA assembly module demonstrates markedly higher efficiency in discerning among various types of cells compared to traditional techniques. This innovative assembly module is expected to offer a new perspective to highlight tumor heterogeneity and guide personalized therapy.

Abstract Acquiring detailed spatial information about intratumor microbiota in situ is challenging, which leaves 3D distributions of microbiota within entire tumors largely unexplored. Here, a modified iDISCO‐CUBIC tissue clearing and D‐amino acid microbiome labeling‐based (miCDaL) strategy are proposed, that integrates microbiota in situ labeling, tissue clearing, and whole‐mount tissue imaging to enable 3D visualization of indigenous intratumor microbiota. Leveraging whole‐mount spatial resolution and centimeter‐scale imaging depth, the 3D biogeography of microbiota is successfully charted across various tumors at different developmental stages, providing quantitative spatial insights in relation to host tumors. By incorporating an immunostaining protocol, 3D imaging of the immunologic microenvironment is achieved in both murine and human mammary tumors that is previously assumed to be bacteria‐free. Notably, immune infiltrates, including T cells and NK cells, and tertiary lymphoid structures are conspicuously absent in bacteria‐colonized regions. This 3D imaging strategy for mapping Indigenous intratumor microbiota offers valuable insights into host–microbiota interactions.

Abstract Single-cell and spatial transcriptome sequencing, two recently optimized transcriptome sequencing methods, are increasingly used to study cancer and related diseases. Cell annotation, particularly for malignant cell annotation, is essential and crucial for in-depth analyses in these studies. However, current algorithms lack accuracy and generalization, making it difficult to consistently and rapidly infer malignant cells from pan-cancer data. To address this issue, we present Cancer-Finder, a domain generalization-based deep-learning algorithm that can rapidly identify malignant cells in single-cell data with an average accuracy of 95.16%. More importantly, by replacing the single-cell training data with spatial transcriptomic datasets, Cancer-Finder can accurately identify malignant spots on spatial slides. Applying Cancer-Finder to 5 clear cell renal cell carcinoma spatial transcriptomic samples, Cancer-Finder demonstrates a good ability to identify malignant spots and identifies a gene signature consisting of 10 genes that are significantly co-localized and enriched at the tumor-normal interface and have a strong correlation with the prognosis of clear cell renal cell carcinoma patients. In conclusion, Cancer-Finder is an efficient and extensible tool for malignant cell annotation.

Abstract To evade immune surveillance, tumor cells express ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) on the surface of their membrane, which degrades extracellular cyclic GMP‐AMP (cGAMP), thereby inhibiting the cyclic GMP‐AMP synthase (cGAS) stimulator of interferon gene (STING) DNA‐sensing pathway. To fully understand this tumor stealth mechanism, it is essential to determine whether other forms of ENPP1 with hydrolytic cGAMP activity also are present in the tumor microenvironment to regulate this innate immune pathway. Herein, it is reported that various tumor‐derived exosomes carry ENPP1, and can hydrolyze synthetic 2′3′‐cGAMP and endogenous 2′3′‐cGAMP produced by cells to inhibit cGAS‐STING pathway in immune cells. Moreover, tumor exosomal ENPP1 also can hydrolyze 2′3′‐cGAMP bound to LL‐37 (an effective transporter of 2′3′‐cGAMP) to inhibit STING signaling. Furthermore, high expression of ENPP1 in exosomes is observed isolated from human breast and lung cancer tissue, and tumor exosomal ENPP1 inhibited the immune infiltration of CD8+ T cells and CD4+ T cells. The results elucidate the essential function of tumor exosomal ENPP1 in the cGAS‐STING pathway, furthering understanding of the crosstalk between the tumor cells and immune system.

Abstract Loss of refreshment in nucleus pulposus (NP) cellularity leads to intervertebral disc (IVD) degeneration. Nevertheless, the cellular sequence of NP cell differentiation remains unclear, although an increasing body of literature has identified markers of NP progenitor cells (NPPCs). Notably, due to their fragility, the physical enrichment of NP‐derived cells has limited conventional transcriptomic approaches in multiple studies. To overcome this limitation, a spatially resolved transcriptional atlas of the mouse IVD is generated via the 10x Genomics Visium platform dividing NP spots into two clusters. Based on this, most reported NPPC‐markers, including Cathepsin K (Ctsk), are rare and predominantly located within the NP‐outer subset. Cell lineage tracing further evidence that a small number of Ctsk‐expressing cells generate the entire adult NP tissue. In contrast, Tie2, which has long suggested labeling NPPCs, is actually neither expressed in NP subsets nor labels NPPCs and their descendants in mouse models; consistent with this, an in situ sequencing (ISS) analysis validated the absence of Tie2 in NP tissue. Similarly, no Tie2‐cre‐mediated labeling of NPPCs is observed in an IVD degenerative mouse model. Altogether, in this study, the first spatial transcriptomic map of the IVD is established, thereby providing a public resource for bone biology.

Abstract Extracellular vesicle (EV) secretion is a dynamic process crucial to cellular communication. Temporally sorting EVs, i.e., separating the newly-produced ones from the pre-existing, can allow not only deep understanding of EV dynamics, but also the discovery of potential EV biomarkers that are related to disease progression or responsible to drug intervention. However, the high similarity between the nascent and pre-existing EVs makes temporal separation extremely challenging. Here, by co-translational introduction of azido groups to act as a timestamp for click chemistry labelling, we develop a microfluidic-based strategy to enable selective isolation of nascent EVs stimulated by an external cue. In two mouse models of anti-PD-L1 immunotherapy, we demonstrate the strategy’s feasibility and reveal the high positive correlation of nascent PD-L1+ EV level to tumor volume, suggesting an important role of nascent EVs in response to immunotherapy in cancer treatment.

Gene expression of cells is a heterogeneous and dynamic program involved in various biological processes. Here, authors develop Well-TEMPseq, a high-throughput, cost-effective, and accurate method for massively parallel profiling of the temporal dynamics of single-cell gene expression.

Abstract Background μ‐opioid receptor agonists (MORAs) are indispensable for analgesia in bladder cancer (BC) patients, both during surgery and for chronic pain treatment. Whether MORAs affect BC progression and metastasis remains largely unknown. This study focused on the effects of MORAs on the formation of circulating tumor cells (CTCs) in BC and aimed to provide potential therapeutic targets, which would retain the pain‐relieving effects of MORAs in BC patients without sacrificing their long‐term prognosis. Methods Different preclinical models were used to identify the effects of MORAs on the progression of BC. A novel immunocapture microfluidic chip was utilized to analyze whether MORAs affected the number of CTCs in mouse models and clinical BC patients. Bioinformatic analyses, total transcriptome sequencing, and molecular biology methods were then used to investigate the underlying mechanisms in these models and in BC cell lines. Results Mouse models of hematogenous metastasis and in situ BC demonstrated that tumor metastasis was significantly increased after MORA treatment. A significant increase in the number of mesenchymal and/or epithelial CTCs was detected after MORA treatment in both the mouse models and clinical trial patients. Mechanistically, MORAs facilitated the formation of CTCs by activating the MOR/PI3K/AKT/Slug signaling pathway, hereby promoting the epithelial‐mesenchymal transition (EMT) of BC cells, as knockdown of MOR, Slug or blockade of PI3K inhibited the EMT process and CTC formation. Conclusion MORAs promoted BC metastasis by facilitating CTC formation. The EMT‐CTC axis could be targeted for preventive measures during MORA treatment to inhibit the associated tumor metastasis or recurrence in BC patients.

The spatial transcriptome has enabled researchers to resolve transcriptome expression profiles while preserving information about cell location to better understand the complex biological processes that occur in organisms. Due to technical limitations, the current high-throughput spatial transcriptome sequencing methods (known as next-generation sequencing with spatial barcoding methods or spot-based methods) cannot achieve single-cell resolution. A single measurement site, called a spot, in these technologies frequently contains multiple cells of various types. Computational tools for determining the cellular composition of a spot have emerged as a way to break through these limitations. These tools are known as deconvolution tools. Recently, a couple of deconvolution tools based on different strategies have been developed and have shown promise in different aspects. The resulting single-cell resolution expression profiles and/or single-cell composition of spots will significantly affect downstream data mining; thus, it is crucial to choose a suitable deconvolution tool. In this review, we present a list of currently available tools for spatial transcriptome deconvolution, categorize them based on the strategies they employ, and explain their advantages and limitations in detail in order to guide the selection of these tools in future studies.

Liquid biopsy offers great promise for noninvasive cancer diagnostics, while the lack of adequate target characterization and analysis hinders its wide application. Here, the authors design a transfer learning-based algorithm to transfer lesion labels from the primary cancer cell atlas to circulating tumor cells.

Abstract The COVID‐19 pandemic, caused by SARS‐CoV‐2, has seriously threatened human life and security in recent years and has had a serious impact on economic development. A range of strategies, including antibodies, small‐molecule agents and vaccines, have been developed and widely used to combat SARS‐CoV‐2. However, the uncertain development and susceptibility to mutation of SARS‐CoV‐2 pose challenges to these approaches, making it necessary to develop a broader range of strategies to complement and expand the diversity of attacks against SARS‐CoV‐2. As promising tools against SARS‐CoV‐2, aptamers have attracted wide attention due to their unique molecular properties. In this review, we survey SARS‐CoV‐2 aptamers and aptamer‐based detection tools as well as aptamer‐based therapeutics. In addition, we analyze the potential value of aptamers in the investigation of SARS‐CoV‐2 infection mechanism and vaccine design. Finally, we look forward to the future development direction of aptamers against SARS‐CoV‐2 or other viruses.

SARS‐CoV‐2 aptamer is a favorable candidate for the recognition and detection of SARS‐CoV‐2, owing to its small size and easy synthesis. However, the issue of compromised binding affinities in real samples and targeting mutant SARS‐CoV‐2 hinder wide applications of the aptamer. In this study, it is discovered that molecular crowding could increase binding affinity of CoV2‐6C3 aptamer against RBD (Receptor Binding Domain) of SARS‐CoV‐2 via increasing the absolute value of the enthalpy change. The values of the equilibrium dissociation constant in molecular crowding decrease by 70% and 150%, respectively, against wild‐type and mutant RBD compared with those in buffer without crowding. Moreover, the detection limit of SARS‐CoV‐2 pseudovirus is up to 5 times lower under molecular crowding compared to dilute conditions. The discovery deepens the understanding of aptamer‐target interaction mechanisms in crowding conditions and provides an effective way to apply SARS‐CoV‐2 aptamer for virus recognition and detection.

Abstract Despite the fast progress in our understanding of the complex functions of gut microbiota, it is still challenging to directly investigate the in vivo microbial activities and processes on an individual cell basis. To gain knowledge of the indigenous growth/division patterns of the diverse mouse gut bacteria with a relatively high throughput, here, we propose an integrative strategy, which combines the use of fluorescent probe labeling, confocal imaging with single‐cell sorting, and sequencing. Mouse gut bacteria sequentially labeled by two fluorescent d‐amino acid probes in vivo were first imaged by confocal microscopy to visualize their growth patterns, which can be unveiled by the distribution of the two fluorescence signals on each bacterium. Bacterial cells of interest on the imaging slide were then sorted using a laser ejection equipment, and the collected cells were then sequenced individually to identify their taxa. Our strategy allows integrated acquirement of the growth pattern knowledge of a variety of gut bacteria and their genomic information on a single‐cell basis, which should also have great potential in studying many other complex bacterial systems.

Abstract Extracellular vesicles (EVs) play an important role in many physiological processes. Thus, EV analysis has a great value for the understanding of mechanisms underlying disease progress or diagnosis, prognosis and therapy. The overlapped physical and immune properties between EVs and events in body fluids, as well as the phenotypic heterogeneity of EVs, require efficient isolation and analysis methods. The unique properties of aptamers, such as facile modification and programmability, make them easily assembled as powerful platforms for EV isolation and analysis. EVs can also be used as vehicles for drug delivery, benefiting from the properties of homing ability, hypo‐immunogenicity, and strong tolerance. The affinity recognition ability to targets and the feature of single stranded DNA of aptamers make them useful in promoting the targetability of EVs and delivery of nucleic acid drugs. This review summarizes recent progress in aptamer‐based EV isolation, analysis, and aptamer‐functionalized EVs for therapeutics.

Circulating tumor cells (CTCs), as important liquid biopsy target, can provide valuable information for cancer progress monitoring and individualized treatment. However, current isolation platforms incapable of balancing capture efficiency, specificity, cell viability, and gentle release have restricted the clinical applications of CTCs. Herein, inspired by the structure and functional merits of natural membrane interfaces, we established an antibody-engineered red blood cell (RBC-Ab) affinity interface on microfluidic chip for high-performance isolation and release of CTCs. The lateral fluidity, pliability, and anti-adhesion property of the RBC microfluidic interface enabled efficient CTCs capture (96.5%), high CTCs viability (96.1%), and high CTCs purity (average 4.2-log depletion of leukocytes). More importantly, selective lysis of RBCs by simply changing the salt concentration was utilized to destroy the affinity interface for efficient and gentle release of CTCs without nucleic acid contamination. Using this chip, CTCs were successfully detected in colon cancer samples with 90% sensitivity and 100% specificity (20 patients and 10 healthy individuals). After the release process, KRAS gene mutations of CTCs were identified from all the 5 cancer samples, which was consistent with the results of tissue biopsy. We expect this RBC interface strategy will inspire further biomimetic interface construction for rare cell analysis.

Abstract While DNA-directed nano-fabrication enables the high-resolution patterning for conventional electronic materials and devices, the intrinsic self-assembly defects of DNA structures present challenges for further scaling into sub-1 nm technology nodes. The high-dimensional crystallographic defects, including line dislocations and grain boundaries, typically lead to the pattern defects of the DNA lattices. Using periodic line arrays as model systems, we discover that the sequence periodicity mainly determines the formation of line defects, and the defect rate reaches 74% at 8.2-nm line pitch. To suppress high-dimensional defects rate, we develop an effective approach by assigning the orthogonal sequence sets into neighboring unit cells, reducing line defect rate by two orders of magnitude at 7.5-nm line pitch. We further demonstrate densely aligned metal nano-line arrays by depositing metal layers onto the assembled DNA templates. The ultra-scaled critical pitches in the defect-free DNA arrays may further promote the dimension-dependent properties of DNA-templated materials.

Abstract Cellular heterogeneity is essential to biological processes, such as embryonic development, cell differentiation, and the progression of disease. Recent years have seen the development of a variety of single‐cell multiomics technologies that systemically codetect the genome, epigenome, transcriptome, and proteome for single‐cell heterogeneity evaluation comprehensively. Microfluidics has emerged as a significant tool for single‐cell multiomics techniques, enabling the analysis of the complex regulatory network associated with genome coding, epigenome regulation, and transcriptome/proteome expression in a single cell with increased detection sensitivity, accuracy, throughput, and integration. A review of state‐of‐the‐art microfluidic single‐cell multiomics analysis is presented here. Various microfluidics for isolating single cells are introduced first, highlighting their advantages, disadvantages, and applications in single‐cell sequencing. Then, a comprehensive overview of microfluidic single‐cell multiomics techniques is provided. In addition, a brief introduction of single‐cell multiomics analysis in biological applications and clinical settings will be presented. Finally, we will conclude by discussing the future challenges and prospects of this field.

Summary: Periostin, a multifunctional extracellular protein, plays an important role in inflammatory disorders and tumorigenesis. Our previous work has demonstrated that periostin deficiency inhibits colorectal cancer (CRC) progression. Here, we aim to clarify the role of periostin in the immune microenvironment of CRC. We find that periostin deficiency significantly decreases the infiltration of programmed death receptor 1 (PD-1)+ tumor-associated macrophages (TAMs) in CRC tissues. Periostin promotes the expression of PD-1 on TAMs by integrin-ILK-nuclear factor κB (NF-κB) signaling, and PD-1+ TAMs produce interleukin-6 (IL-6) and interferon γ (IFN-γ) to induce the expression of PD-L1 on colorectal tumor cells. Moreover, combined inhibition of periostin and PD-1 significantly suppresses CRC progression compared with the inhibition of periostin or PD-1 alone. In summary, our results suggest that periostin deficiency reduces the infiltration of PD-1+ TAMs and enhances the efficacy of anti-PD-1 treatment in CRC.

Transmission of bacterial endospores between the environment and people and the following germination in vivo play critical roles in both the deadly infections of some bacterial pathogens and the stabilization of the commensal microbiotas in humans. Our knowledge about the germination process of different bacteria in the mammalian gut, however, is still very limited due to the lack of suitable tools to visually monitor this process. We proposed a two-step labeling strategy that can image and quantify the endospores’ germination in the recipient’s intestines. Endospores collected from donor’s gut microbiota were first labeled with fluorescein isothiocyanate and transplanted to mice via gavage. The recipient mice were then administered with Cyanine5-tagged D-amino acid to label all the viable bacteria, including the germinated endospores, in their intestines in situ. The germinated donor endospores could be distinguished by presenting two types of fluorescent signals simultaneously. The integrative use of cell-sorting, 16S rDNA sequencing, and fluorescence in situ hybridization (FISH) staining of the two-colored bacteria unveiled the taxonomic information of the donor endospores that germinated in the recipient’s gut. Using this strategy, we investigated effects of different germinants and pre-treatment interventions on their germination, and found that germination of different commensal bacterial genera was distinctly affected by various types of germinants. This two-color labeling strategy shows its potential as a versatile tool for visually monitoring endospore germination in the hosts and screening for new interventions to improve endospore-based therapeutics.

Abstract Given the continuous and growing demand for point of care (POC) diagnostic tests, attention has been shifted toward integration and miniaturization of laboratory protocols into “sample‐in‐answer‐out” devices. Microfluidic technologies have been considered an ideal solution to address the requirements of POC diagnostics since many laboratory functions can be miniaturized and incorporated onto a single integrated chip. In this review, we summarize the advances of integrated microfluidic devices for POC diagnostics in the last 3 years. Particularly, we summarize current materials used for microfluidic chip fabrication, discuss the innovation of versatile integrated microfluidic devices, especially the strategies for simplifying sample preparation in manual or self‐driven systems, and new detection methods of microfluidic chips. In addition, we describe new integrated microfluidic devices for POC diagnostics of protein‐targeted immunodiagnostics, nucleic acid molecular tests, and small molecule metabolites analysis. We also provide future perspectives and current challenges for clinical translation and commercialization of these microfluidic technologies.

Here, the authors combine 3D printing and liquid metal filling techniques to fabricate customised probeheads for magnetic resonance experiments. They demonstrate in situ electrochemical nuclear magnetic resonance analysis, reaction monitoring with continues-flow separation and small-sample imaging.

Single-cell RNA-seq can reveal accurate and precise cell types and states. Here the authors present an scRNA-seq platform, Paired-seq, which uses differential flow resistance to achieve 95% cell utilisation efficiency for improved cell-free RNA removal and gene detection.

Abstract Objective To ascertain whether en bloc resection could reduce the risk of seeding cancer cells into the circulation during the resection of non-muscle invasive bladder cancer (NMIBC). Methods Patients with primary NMIBC were enrolled in this prospective study from October 2017 to May 2018. Patients were allocated to receive conventional transurethral resection of the bladder (TURB) or retrograde en bloc resection technique of the bladder tumor (RERBT). Blood samples (1 ml) for circulating tumor cell (CTC) enumeration were drawn from the peripheral vein prior to resection (PV1), immediately after resection of the tumor base (PV2), and at 12 h after resection (PV3). Intra-group comparisons of the changes in the number of CTCs identified among the PV1, PV2, and PV3 blood samples were performed in each group. Results A total of 21 patients (12 in the RERBT group and 9 in the TURB group) were recruited. For patients receiving TURB, the level of CTCs identified in PV3 was significantly higher than that in PV1 (p = 0.047). However, there was no significant difference in CTC counts before and after resection in the RERBT group. Conclusion RERBT did not increase the number of tumor cells in the bloodstream.

For positioning tasks of mobile robots in indoor environments, the emerging positioning technique based on visual inertial odometry (VIO) is heavily influenced by light and suffers from cumulative errors, which cannot meet the requirements of long-term navigation and positioning. In contrast, positioning techniques that rely on indoor signal sources such as 5G and geomagnetism can provide drift-free global positioning results, but their overall positioning accuracy is low. In order to obtain higher precision and more reliable positioning, this paper proposes a fused 5G/geomagnetism/VIO indoor localization method. Firstly, the error back propagation neural network (BPNN) model is used to fuse 5G and geomagnetic signals to obtain more reliable global positioning results; secondly, the conversion relationship from VIO local positioning results to the global coordinate system is established through the least squares principle; and finally, a fused 5G/geomagnetism/VIO localization system based on the error state extended Kalman filter (ES-EKF) is constructed. The experimental results show that the 5G/geomagnetism fusion localization method overcomes the problem of low accuracy of single sensor localization and can provide more accurate global localization results. Additionally, after fusing the local and global positioning results, the average positioning error of the mobile robot in the two scenarios is 0.61 m and 0.72 m. Compared with the VINS-mono algorithm, our approach improves the average positioning accuracy in indoor environments by 69.0% and 67.2%, respectively.

Infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing the rapid spread of coronavirus disease 2019 (COVID-19), has generated a public health crisis worldwide. The molecular mechanisms of SARS-CoV-2 infection and virus–host interactions are still unclear. In this study, we identified four unique microRNA-like small RNAs encoded by SARS-CoV-2. SCV2-miR-ORF1ab-1-3p and SCV2-miR-ORF1ab-2-5p play an important role in evasion of type I interferon response through targeting several genes in type I interferon signaling pathway. Particularly worth mentioning is that highly expressed SCV2-miR-ORF1ab-2-5p inhibits some key genes in the host innate immune response, such as IRF7, IRF9, STAT2, OAS1, and OAS2. SCV2-miR-ORF1ab-2-5p has also been found to mediate allelic differential expression of COVID-19-susceptible gene OAS1. In conclusion, these results suggest that SARS-CoV-2 uses its miRNAs to evade the type I interferon response and links the functional viral sequence to the susceptible genetic background of the host.

Abstract Controllable assembly and disassembly of recognition interface are vital for bioanalysis. Herein, a strategy of dynamic manipulation of trapping force by engineering a dynamic and reversible immunoaffinity microinterface (DynarFace) in a herringbone chip (DynarFace‐Chip) for liquid biopsy is proposed. The DynarFace is assembled by magnetically attracting immunomagnetic beads (IMBs) on chip substrate, with merits of convenient operation and reversible assembly. The DynarFace allows accumulating attachment of IMBs on circulating rare cell (CRC) surfaces during hydrodynamically enhanced interface collision, where accumulatively enhanced magnetic trapping force improves capture efficiency toward CRCs with medium expression of biomarkers from blood samples by 134.81% compared with traditional non‐dynamic interfaces. Moreover, magnet withdrawing‐induced disappearance of trapping force affords DynarFace disassembly and CRC release with high efficiency (>98%) and high viability (≈98%), compatible with downstream in vitro culture and gene analysis of CRCs. This DynarFace strategy opens a new avenue to accumulated capture and reversible release of CRCs, holding great potential for liquid biopsy‐based precision medicine.

Rat is a widely used mammalian model for gut microbiota research. However, due to the difficulties of individual in vitro culture of many of the gut bacteria, much information about the microbial behaviors in the rat gut remains largely unknown. Here, to characterize the in situ growth and division of rat gut bacteria, we apply a chemical strategy that integrates the use of sequential tagging with D-amino acid-based metabolic probes (STAMP) with fluorescence in situ hybridization (FISH) to rat gut microbiota. Following sequential gavages of two different fluorescent D-amino acid probes to rats, the resulting dually labeled gut bacteria provides chronological information of their in situ cell wall synthesis. After taxonomical labeling with FISH probes, most of which are newly designed in this study, we successfully identify the growth patterns of 15 bacterial species, including two that have not been cultured separately in the laboratory. Furthermore, using our labeling protocol, we record Butyrivibrio fibrisolvens cells growing at different growth stages of a complete cell division cycle, which offers a new scope for understanding basic microbial activities in the gut of mammalian hosts.

How to study the unculturable bacteria in the laboratory is one of the major challenges in human gut microbiota research. The resulting lack of microbiology knowledge of this “dark matter” greatly hinders further understanding of our gut microbiota. Here, to characterize the in vivo growth and division of human gut bacteria, we report the integrative use of STAMP (sequential tagging with D-amino acid–based metabolic probes) and fluorescence in situ hybridization (FISH) in a human microbiota-associated mouse model. After stable colonization of the human fecal microbiotas in germ-free mice, two fluorescent D-amino acid probes were sequentially administered by gavage, and the dually labeled peptidoglycan of the bacteria provided a chronological recording of their cell wall syntheses. Following taxonomic identification with FISH staining, the growth patterns of 32 species, including 5 currently unculturables, were identified. Surprisingly, we found that many bacterial species in the human microbiota were significantly shorter than those in the mouse gut microbiota. An imaging database for gut bacteria ̶ Microbiome Atlas was built for summarizing STAMP imaging of bacteria from different microbiotas, which can be contributed by the microbiota research community worldwide. This integrative imaging strategy and the database will promote our understanding of the bacterial cytology in gut microbiotas and facilitate communications among cellular microbiologists.

The wide use of cooperative missions using multiple unmanned platforms has made relative distance information an essential factor for cooperative positioning and formation control. Reducing the range error effectively in real time has become the main technical challenge. We present a new method to deal with ranging errors based on the distance increment (DI). The DI calculated by dead reckoning is used to smooth the DI obtained by the cooperative positioning, and the smoothed DI is then used to detect and estimate the non-line-of-sight (NLOS) error as well as to smooth the observed values containing random noise in the filtering process. Simulation and experimental results show that the relative accuracy of NLOS estimation is 8.17%, with the maximum random error reduced by 40.27%. The algorithm weakens the influence of NLOS and random errors on the measurement distance, thus improving the relative distance precision and enhancing the stability and reliability of cooperative positioning.