Phage-Based Profiling of Rare Single Cells Using Nanoparticle-Directed Capture

A Bio-Inspired Free-Standing Film with Versatility: From Heterogeneous CTCs Programed Isolating to Breast Cancer Molecular Typing

Developing a robust strategy for profiling heterogeneous circular tumor cells specifically, distinguishing the phenotypes of which in blood sample of cancer patient precisely, and releasing them sequentially, is significant for cancer management by liquid biopsy. Herein, a bio-inspired free-standing and flexible film composed of TiO2 nanotube and silk fibroin, fabricated with multiply dynamic bioactive surface (TSF/MDBS) by a simple and eco-friendly way including using polydopamine chemistry and dual dynamic covalent chemistry, is reported. The as-prepared TSF/MDBS binds specific peptides toward cells with epithelial biomarker and human epithelial growth factor receptor 2 (HER2) biomarker, and antifouling agents bovine serum albumin for obviating platelets and proteins adhering of blood, can capture heterogeneous CTCs with enhanced capability due to the cytocompatible soft film and exquisite surface design, and further release the captured cells as program, by specifically breaking down the covalent bonds in sequence via the action of adding biocompatible molecules fructose and glutathione. By applying the TSF/MDBS, it can be tailored into desired pieces for identifying CTCs with different phenotypes (HER2-high and HER2-low) from the unprocessed blood samples of breast cancer patients, and finally profiling these heterogeneous CTCs, to discriminate HER2 positive or negative of breast cancer patients in clinical applications.

Nanomaterial-Based Strategies for Preventing Tumor Metastasis by Interrupting the Metastatic Biological Processes

Tumor metastasis is the primary cause of cancer-related deaths. The prevention of tumor metastasis has garnered notable interest and interrupting metastatic biological processes is considered a potential strategy for preventing tumor metastasis. The tumor microenvironment (TME), circulating tumor cells (CTCs), and premetastatic niche (PMN) play crucial roles in metastatic biological processes. These processes can be interrupted using nanomaterials due to their excellent physicochemical properties. However, most studies have focused on only one aspect of tumor metastasis. Here, the hypothesis that nanomaterials can be used to target metastatic biological processes and explore strategies to prevent tumor metastasis is highlighted. First, the metastatic biological processes and strategies involving nanomaterials acting on the TME, CTCs, and PMN to prevent tumor metastasis are briefly summarized. Further, the current challenges and prospects of nanomaterials in preventing tumor metastasis by interrupting metastatic biological processes are discussed. Nanomaterial-and multifunctional nanomaterial-based strategies for preventing tumor metastasis are advantageous for the long-term fight against tumor metastasis and their continued exploration will facilitate rapid progress in the prevention, diagnosis, and treatment of tumor metastasis. Novel perspectives are outlined for developing more effective strategies to prevent tumor metastasis, thereby improving the outcomes of patients with cancer.

Single-Cell Proteomics by Barcoded Phage-Displayed Screening via an Integrated Microfluidic Chip

Recent advancements in the profiling of proteomes at the single-cell level necessitate the development of quantitative and versatile platforms, particularly for analyzing rare cells like circulating tumor cells (CTCs). In this chapter, we present an integrated microfluidic chip that utilizes magnetic nanoparticles to capture single tumor cells with exceptional efficiency. This chip enables on-chip incubation and facilitates in situ analysis of cell-surface protein expression. By combining phage-based barcoding with next-generation sequencing technology, we successfully monitored changes in the expression of multiple surface markers induced by CTC adherence. This innovative platform holds significant potential for comprehensive screening of multiple surface antigens simultaneously in rare cells, offering single-cell resolution. Consequently, it will contribute valuable insights into biological heterogeneity and human disease.

Status and developmental trends in recombinant collagen preparation technology

Recombinant collagen is a pivotal topic in foundational biological research and epitomizes the application of critical bioengineering technologies. These technological advancements have profound implications across diverse areas such as regenerative medicine, organ replacement, tissue engineering, cosmetics and more. Thus, recombinant collagen and its preparation methodologies rooted in genetically engineered cells mark pivotal milestones in medical product research. This article provides a comprehensive overview of the current genetic engineering technologies and methods used in the production of recombinant collagen, as well as the conventional production process and quality control detection methods for this material. Furthermore, the discussion extends to foresee the strides in physical transfection and magnetic control sorting studies, envisioning an enhanced preparation of recombinant collagen-seeded cells to further fuel recombinant collagen production.

Recent methodological advances towards single-cell proteomics

Studying the central dogma at the single-cell level has gained increasing attention to reveal hidden cell lineages and functions that cannot be studied using traditional bulk analyses. Nonetheless, most single-cell studies exploiting genomic and transcriptomic levels fail to address information on proteins that are central to many important biological processes. Single-cell proteomics enables understanding of the functional status of individual cells and is particularly crucial when the specimen is composed of heterogeneous entities of cells. With the growing importance of this field, significant methodological advancements have emerged recently. These include miniaturized and automated sample preparation, multi-omics analyses, and combined analyses of multiple techniques such as mass spectrometry and microscopy. Moreover, artificial intelligence and single-molecule detection technologies have advanced throughput and improved sensitivity limitations, respectively, over conventional methods. In this review, we summarize cutting-edge methodologies for single-cell proteomics and relevant emerging technologies that have been reported in the last 5 years, and provide an outlook on this research field.

M13 Bacteriophage-Assisted Recognition and Signal Spatiotemporal Separation Enabling Ultrasensitive Light Scattering Immunoassay

The demand for the ultrasensitive and rapid quantitative analysis of trace target analytes has become increasingly urgent. However, the sensitivity of traditional immunoassay-based detection methods is limited due to the contradiction between molecular recognition and signal amplification caused by the size effect of nanoprobes. To address this dilemma, we describe versatile M13 phage-assisted immunorecognition and signal transduction spatiotemporal separation that enable ultrasensitive light-scattering immunoassay systems for the quantitative detection of low-abundance target analytes. The newly developed immunoassay strategy combines the M13 phage-assisted light scattering signal fluctuations of gold nanoparticles (AuNPs) with gold in situ growth (GISG) technology. Given the synergy of M13 phage-mediated leverage effect and GISG-amplified light scattering signal modulation, the practical detection capability of this strategy can achieve the ultrasensitive and rapid quantification of ochratoxin A and alpha-fetoprotein in real samples at the subfemtomolar level within 50 min, displaying about 4 orders of magnitude enhancement in sensitivity compared with traditional phage-based ELISA. To further improve the sensitivity of our immunoassay, the biotin-streptavidin amplification scheme is implemented to detect severe acute respiratory syndrome coronavirus 2 spike protein down to the attomolar range. Overall, this study offers a direction for ultrasensitive quantitative detection of target analytes by the synergistic combination of M13 phage-mediated leverage effect and GISG-amplified light scattering signal modulation.

Microfluidic systems for particle capture and release: A review

Microfluidic technology has emerged as a promising tool in various applications, including biosensing, disease diagnosis, and environmental monitoring. One of the notable features of microfluidic devices is their ability to selectively capture and release specific cells, biomolecules, bacteria, and particles. Compared to traditional bulk analysis instruments, microfluidic capture-and-release platforms offer several advantages, such as contactless operation, label-free detection, high accuracy, good sensitivity, and minimal reagent requirements. However, despite significant efforts dedicated to developing innovative capture mechanisms in the past, the release and recovery efficiency of trapped particles have often been overlooked. Many previous studies have focused primarily on particle capture techniques and their efficiency, disregarding the crucial role of successful particle release for subsequent analysis. In reality, the ability to effectively release trapped particles is particularly essential to ensure ongoing, high-throughput analysis. To address this gap, this review aims to highlight the importance of both capture and release mechanisms in microfluidic systems and assess their effectiveness. The methods are classified into two categories: those based on physical principles and those using biochemical approaches. Furthermore, the review offers a comprehensive summary of recent applications of microfluidic platforms specifically designed for particle capture and release. It outlines the designs and performance of these devices, highlighting their advantages and limitations in various target applications and purposes. Finally, the review concludes with discussions on the current challenges faced in the field and presents potential future directions.

M13 phage: a versatile building block for a highly specific analysis platform

Viruses are changing the biosensing and biomedicine landscape due to their multivalency, orthogonal reactivities, and responsiveness to genetic modifications. As the most extensively studied phage model for constructing a phage display library, M13 phage has received much research attention as building blocks or viral scaffolds for various applications including isolation/separation, sensing/probing, and in vivo imaging. Through genetic engineering and chemical modification, M13 phages can be functionalized into a multifunctional analysis platform with various functional regions conducting their functionality without mutual disturbance. Its unique filamentous morphology and flexibility also promoted the analytical performance in terms of target affinity and signal amplification. In this review, we mainly focused on the application of M13 phage in the analytical field and the benefit it brings. We also introduced several genetic engineering and chemical modification approaches for endowing M13 with various functionalities, and summarized some representative applications using M13 phages to construct isolation sorbents, biosensors, cell imaging probes, and immunoassays. Finally, current issues and challenges remaining in this field were discussed and future perspectives were also proposed.

Fabrication of Channeled and Three-Dimensional Electrodes for the Integrated Capture and Detection of Invasive Circulating Tumor Cells during Hematogenous Metastasis

Hematogenous metastasis is the main route of cancer spreading, causing majority death of cancer patients. During this process, platelets in the blood are found increasingly essential to promote hematogenous metastasis by forming platelet-interacted circulating tumor cells (CTCs). Hence, we aim to fabricate an integrated method for the availability of capture and detection of such invasive CTCs. Specifically, a new form of channeled and conductive three-dimensional (3D) electrode is constructed by modifying a conductive layer and capture antibody on the templated and channeled poly(dimethylsiloxane) scaffold. The modified antibody enables the capture of the platelet-interacted CTC hybrid, while the conductive layer significantly facilitates electron transfer from electro-active signal molecules that are targeting platelets. Therefore, sensitive electrochemical detection of platelet-interacted CTCs has been realized. Efficient capture and sensitive detection have been demonstrated by this work. Additionally, dynamic analysis of patients' CTCs has also been conducted to provide accurate information about disease assessment and efficacy evaluation. The cut-off line was set as 5.15 nA based on the sample signals from healthy volunteers. Thus, stage III cancer patients with high risk of hematogenous metastasis have been identified. Together, this work shows the development of a new strategy for simultaneous capture and detection of the invasive CTC subtype form patient blood, which favors precise monitoring of hematogenous metastasis.

Microfluidic Mixer for In Situ Ammonia Analysis of Single Cells in Mass Spectrometry

Mass spectrometry (MS) is a powerful tool for exploring single-cell heterogeneity. However, due to the ultralow absolute content of most substances in a single cell, existing methods can only analyze high-content substances; conventional methods are incompetent for quantitative analysis of important trace-amount small-molecule metabolites such as ammonia and sulfide. Herein, a method integrating single-cell extraction, online derivatization, and MS for multifunctional and more accurate MS analysis is reported. For application, ammonia content in a single cell was analyzed, where the cellular heterogeneity in ammonia metabolism was revealed. First, the extraction room of a microfluidic probe was covered on the target single cell, and the extraction fluid was allowed to flow through a single cell and dissolve cellular ammonia. Then, the ammonia was mixed and reacted with the pretreatment reagent input from another inlet to achieve the derivatization and signal amplification, enhancing the analysis sensitivity on MS. Finally, the sample was sent to MS, and the ammonia content was successfully quantitatively evaluated by analyzing its derivative urotropine, demonstrating the potential of this method to advance single-cell mass spectrometry analysis to higher sensitivity.