Magnetic capture of polydopamine-encapsulated Hela cells for the analysis of cell surface proteins

Single-Cell Nanoencapsulation: Chemical Synthesis of Artificial Cell-in-Shell Spores

Nature has evolved adaptive strategies to protect living cells and enhance their resilience against hostile environments, exemplified by bacterial and fungal spores. Inspired by cryptobiosis in nature, chemists have designed and synthesized artificial "cell-in-shell" structures, endowed with the protective and functional capabilities of nanoshells. The cell-in-shells hold the potential to overcome the inherent limitations of biologically naı̈ve cells, enabling the acquisition of exogenous phenotypic traits through the chemical process known as single-cell nanoencapsulation (SCNE). This review highlights recent advancements in the development of artificial spores, with sections organized based on the categorization of material types utilized in SCNE, specifically organic, hybrid, and inorganic types. Particular emphasis is placed on the cytoprotective and multifunctional roles of nanoshells, demonstrating potential applications of SCNEd cells across diverse fields, including synthetic biology, biochemistry, materials science, and biomedical engineering. Furthermore, the perspectives outlined in this review propose future research directions in SCNE, with the goal of achieving fine-tuned precision in chemical modulation at both intracellular and pericellular levels, paving the way for the design and construction of customized artificial spores tailored to meet specific functional needs.

FLOT2 promotes nasopharyngeal carcinoma progression through suppression of TGF-β pathway via facilitating CD109 expression

In nasopharyngeal carcinoma (NPC), the TGF-β/Smad pathway genes are altered with inactive TGF-β signal, but the mechanisms remain unclear. RNA-sequencing results showed that FLOT2 negatively regulated the TGF-β signaling pathway via up-regulating CD109 expression. qRT-PCR, western blot, ChIP, and dual-luciferase assays were used to identify whether STAT3 is the activating transcription factor of CD109. Co-IP immunofluorescence staining assays were used to demonstrate the connection between FLOT2 and STAT3. In vitro and in vivo experiments were used to detect whether CD109 could rescue the functional changes of NPC cells resulting from FLOT2 alteration. IHC and Spearman correlation coefficients were used to assay the correlation between FLOT2 and CD109 expression in NPC tissues. Our results found that FLOT2 promotes the development of NPC by inhibiting TGF-β signaling pathway via stimulating the expression of CD109 by stabilizing STAT3, which provides a potential therapeutic strategy for NPC treatment.

Electrochemiluminescence sensing of HeLa cells labeled with biotinylated ruthenium complex using bipolar electrode based on microwell modified optical fiber

Biotinylated ruthenium complexes exhibit improved photoluminescent (PL) properties when they bind with streptavidin, making them useful labels or probes in bio-related analysis. However, their ECL properties are still unknown to date. Herein, we reported the use of [Ru(bpy)2(biot-bpy)]2+ complexes as a new ECL luminophore, which was functionalized with biotin moiety and exhibited higher ECL efficiency after binding to streptavidin. Moreover, [Ru(bpy)2(biot-bpy)]2+ complexes could be attached to HeLa cells through the biotin-streptavidin binding. A microwell bipolar electrode (MBE) prepared at one end of an optical fiber bundle was applied to produce ECL of the labeled HeLa cells, which was remotely detected at the other end. The [Ru(bpy)2(biot-bpy)]2+-streptavidin binding effect together with the high surface/volume ratio of MBE promoted the ECL generation on HeLa cells, which was applied to sensitively detect HeLa cells with a linear range from 1.56 × 102 to 6.74 × 106 cells/mL and a detection limit of 83 cells/mL. Moreover, ECL images were successfully acquired to resolve the emission on each HeLa cell. Such cytosensor based on [Ru(bpy)2(biot-bpy)]2+ and MBE may extend the applications of ECL for cell detections.

Recent Advances in the Nanoshells Approach for Encapsulation of Single Probiotics

The intestine, often referred to as the "second brain" of the human body, houses a vast microbial community that plays a crucial role in maintaining the host's balance and directly impacting overall health. Probiotics, a type of beneficial microorganism, offer various health benefits when consumed. However, probiotics face challenges such as acidic conditions in the stomach, bile acids, enzymes, and other adverse factors before they can colonize the intestinal tissues. At present, pills, dry powder, encapsulation, chemically modified bacteria, and genetically engineered bacteria have emerged as the preferred method for the stable and targeted delivery of probiotics. In particular, the use of nanoshells on the surface of single probiotics has shown promise in regulating their growth and differentiation. These nanoshells can detach from the probiotics' surface upon reaching the intestine, facilitating direct contact between the probiotics and intestinal mucosa. In this perspective, we provide an overview of the current developments in the formation of nanoshells mediated by single probiotics. We also discuss the advantages and disadvantages of different nanocoating strategies and explore future trends in probiotic protection.

A Decade of Advances in Single-Cell Nanocoating for Mammalian Cells

Strategic advances in the single-cell nanocoating of mammalian cells have noticeably been made during the last decade, and many potential applications have been demonstrated. Various cell-coating strategies have been proposed via adaptation of reported methods in the surface sciences and/or materials identification that ensure the sustainability of labile mammalian cells during chemical manipulation. Here an overview of the methodological development and potential applications to the healthcare sector in the nanocoating of mammalian cells made during the last decade is provided. The materials used for the nanocoating are categorized into polymers, hydrogels, polyphenolic compounds, nanoparticles, and minerals, and the corresponding strategies are described under the given set of materials. It also suggests, as a future direction, the creation of the cytospace system that is hierarchically composed of the physically separated but mutually interacting cellular hybrids.

Rapid isolation and proteome analysis of urinary exosome based on double interactions of Fe3O4@TiO2-DNA aptamer

There are accumulating evidence that proteins carried by exosomes in urine are most possibly used as biomarkers or therapeutic carriers for certain diseases. The isolation of exosomes is therefore highly desirable for aiding the downstream protein analysis. Particularly, urine is a dynamic biological fluid changing within a short time, resulting in that the separation of urinary exosome requires more efficient technology. Here, a new biocompatible material (denoted as Fe₃O₄@TiO₂-CD63 aptamer) is designed and synthesized for rapid exosome isolation from human urine, depending on the double interactions of TiO₂ with phosphate groups as well as aptamers with specific exosome proteins. Moreover, within 10 min, 92.6% exosomes with intact structure are captured from urine by Fe₃O₄@TiO₂-CD63 aptamers, from which 999 proteins are detected through LC-MS/MS.

RaftProt V2: understanding membrane microdomain function through lipid raft proteomes

Cellular membranes feature dynamic submicrometer-scale lateral domains termed lipid rafts, membrane rafts or glycosphingolipid-enriched microdomains (GEM). Numerous proteomics studies have been conducted on the lipid raft proteome, however, interpretation of individual studies is limited by potential undefined contaminant proteins. To enable integrated analyses, we previously developed RaftProt (http://lipid-raft-database.di.uq.edu.au/), a searchable database of mammalian lipid raft-associated proteins. Despite being a highly used resource, further developments in annotation and utilities were required. Here, we present RaftProt V2 (http://raftprot.org), an improved update of RaftProt. Besides the addition of new datasets and re-mapping of all entries to both UniProt and UniRef IDs, we have implemented a stringent annotation based on experimental evidence level to assist in identification of possible contaminant proteins. RaftProt V2 allows for simultaneous search of multiple proteins/experiments at the cell/tissue type and UniRef/Gene level, where correlations, interactions or overlaps can be investigated. The web-interface has been completely re-designed to enable interactive data and subset selection, correlation analysis and network visualization. Overall, RaftProt aims to advance our understanding of lipid raft function through integrative analysis of datasets collected from diverse tissue and conditions. Database URL: http://raftprot.org.

An overview on enrichment methods for cell surface proteome profiling

Cell surface proteins are essential for many important biological processes, including cell-cell interactions, signal transduction, and molecular transportation. With the characteristics of low abundance, high hydrophobicity, and high heterogeneity, it is difficult to get a comprehensive view of cell surface proteome by direct analysis. Thus, it is important to selectively enrich the cell surface proteins before liquid chromatography with mass spectrometry analysis. In recent years, a variety of enrichment methods have been developed. Based on the separation mechanism, these methods could be mainly classified into three types. The first type is based on their difference in the physicochemical property, such as size, density, charge, and hydrophobicity. The second one is based on the bimolecular affinity interaction with lectin or antibody. And the third type is based on the chemical covalent coupling to free side groups of surface-exposed proteins or carbohydrate chains, such as primary amines, carboxyl groups, glycan side chains. In addition, metabolic labeling and enzymatic reaction-based methods have also been employed to selectively isolate cell surface proteins. In this review, we will provide a comprehensive overview of the enrichment methods for cell surface proteome profiling.

Proteomic Analysis of Lipid Rafts from RBL-2H3 Mast Cells

Lipid rafts are highly ordered membrane microdomains enriched in cholesterol, glycosphingolipids, and certain proteins. They are involved in the regulation of cellular processes in diverse cell types, including mast cells (MCs). The MC lipid raft protein composition was assessed using qualitative mass spectrometric characterization of the proteome from detergent-resistant membrane fractions from RBL-2H3 MCs. Using two different post-isolation treatment methods, a total of 949 lipid raft associated proteins were identified. The majority of these MC lipid raft proteins had already been described in the RaftProtV2 database and are among highest cited/experimentally validated lipid raft proteins. Additionally, more than half of the identified proteins had lipid modifications and/or transmembrane domains. Classification of identified proteins into functional categories showed that the proteins were associated with cellular membrane compartments, and with some biological and molecular functions, such as regulation, localization, binding, catalytic activity, and response to stimulus. Furthermore, functional enrichment analysis demonstrated an intimate involvement of identified proteins with various aspects of MC biological processes, especially those related to regulated secretion, organization/stabilization of macromolecules complexes, and signal transduction. This study represents the first comprehensive proteomic profile of MC lipid rafts and provides additional information to elucidate immunoregulatory functions coordinated by raft proteins in MCs.