OMEF biochip for evaluating red blood cell deformability using dielectrophoresis as a diagnostic tool for type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2DM) is a prevalent and debilitating disease with numerous health risks, including cardiovascular diseases, kidney dysfunction, and nerve damage. One important aspect of T2DM is its association with the abnormal morphology of red blood cells (RBCs), which leads to increased blood viscosity and impaired blood flow. Therefore, evaluating the mechanical properties of RBCs is crucial for understanding the role of T2DM in cellular deformability.

Next-Generation Microfluidics for Biomedical Research and Healthcare Applications.

Microfluidic systems offer versatile biomedical tools and methods to enhance human convenience and health. Advances in these systems enables next-generation microfluidics that integrates automation, manipulation, and smart readout systems, as well as design and three-dimensional (3D) printing for precise production of microchannels and other microstructures rapidly and with great flexibility. These 3D-printed microfluidic platforms not only control the complex fluid behavior for various biomedical applications, but also serve as microconduits for building 3D tissue constructs-an integral component of advanced drug development, toxicity assessment, and accurate disease modeling.

Spike- and nucleocapsid-based gold colloid assay toward the development of an adhesive bandage for rapid SARS-CoV-2 immune response detection and screening.

Immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies are important biomarkers used for the diagnosis and screening of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in both symptomatic and asymptomatic individuals. These antibodies are highly specific to the spike (S) and nucleocapsid (N) proteins of the SARS-CoV-2 virus. This paper outlines the development steps of a novel hybrid (vertical-lateral-vertical) flow assay in the form of a finger-stick point-of-care device, similar to an adhesive bandage, designed for the timely detection and screening of IgM and IgG immune responses to SARS-CoV-2 infections.

Affinity-Based Microfluidics Combined with Atomic Force Microscopy for Isolation and Nanomechanical Characterization of Circulating Tumor Cells.

In this chapter, we present the materials and methods required to isolate and characterize circulating tumor cells (CTCs) from blood samples of cancer patients based on our newly developed microfluidic technologies. In particular, the devices presented herein are designed to be compatible with at\omic force microscopy (AFM) for post-capture nanomechanical investigation of CTCs. Microfluidics is well-established as a technology for isolating CTCs from the whole blood of cancer patients, and AFM is a gold standard for quantitative biophysical analysis of cells.

3D Generation of Multipurpose Atomic Force Microscopy Tips.

In this work, 3D polymeric atomic force microscopy (AFM) tips, referred to as 3DTIPs, are manufactured with great flexibility in design and function using two-photon polymerization. With the technology holding a great potential in developing next-generation AFM tips, 3DTIPs prove effective in obtaining high-resolution and high-speed AFM images in air and liquid environments, using common AFM modes. In particular, it is shown that the 3DTIPs provide high-resolution imaging due to their extremely low Hamaker constant, high speed scanning rates due to their low quality factor, and high durability due to their soft nature and minimal isotropic tip wear; the three important features for advancing AFM studies.

Characterizing circulating tumor cells using affinity-based microfluidic capture and AFM-based biomechanics.

Elasticity and bio-adhesiveness of circulating tumor cells (CTCs) are important biomarkers of cancer. CTCs are rare in blood, thus their capture and atomic force microscopy (AFM)-based biomechanical characterization require use of multifunctional microfluidic device. Here, we describe procedures for fabrication of such device, AFM-Chip, and give details on its use in affinity-based CTC capture, and integration with AFM via reversable physical assembly.

A Method to Efficiently Cryopreserve Mammalian Cells on Paper Platforms.

This protocol describes a simple method to cryopreserve mammalian cells within filter papers as an alternative to conventional slow-freezing approach. The method involves treating paper fibers with fibronectin, using low concentrations of the cryoprotectant dimethyl sulfoxide (DMSO), and slow freezing cells to -80 °C at a 1 °C min rate. In our method, the biocompatibility, large surface area, 3D porosity and fiber flexibility of the paper, in combination with the fibronectin treatment, yield recovery of cells comparable to conventional approaches, with no additional fine-tuning to freezing and thawing procedures.

Cryopreservable arrays of paper-based 3D tumor models for high throughput drug screening.

Three-dimensional (3D) tumor models have gained increased attention in life-science applications as they better represent physiological conditions of in vivo tumor microenvironments, and thus, possess big potential for guiding drug screening studies. Although various techniques proved effective in growing cancer cells in 3D, their procedures are typically complex, time consuming, and expensive. Here, we present a versatile, robust, and cost-effective method that utilizes a paper platform to create cryopreservable high throughput arrays of 3D tumor models.

Airplug-mediated isolation and centralization of single T cells in rectangular microwells for biosensing.

Sorting cells in a single cell per microwell format is of great interest to basic biology studies, biotherapeutics, and biosensing including cell phenotyping. For instance, isolation of individual immune T cells in rectangular microwells has been shown to empower the multiplex cytokine profiling at the single cell level for therapeutics applications. The present study, however, shows that there is an existing bias in temporal cytokine sensing that originates from random "unpredicted" positions of loaded cells within the rectangular microwells.

Paper-Based Cell Cryopreservation.

The continuous development of simple and practical cell cryopreservation methods is of great importance to a variety of sectors, especially when considering the efficient short- and long-term storage of cells and their transportation. Although the overall success of such methods has been increased in recent years, there is still need for a unified platform that is highly suitable for efficient cryogenic storage of cells in addition to their easy-to-manage retrieval. Here, a paper-based cell cryopreservation method as an alternative to conventional cryopreservation methods is presented.

AFM-compatible microfluidic platform for affinity-based capture and nanomechanical characterization of circulating tumor cells.

Circulating tumor cells (CTCs) carried by the patient's bloodstream are known to lead to the metastatic spread of cancer. It is becoming increasingly clear that an understanding of the nanomechanical characteristics of CTCs, such as elasticity and adhesiveness, represents advancements in tracking and monitoring cancer progression and metastasis. In the present work, we describe a combined microfluidic-atomic force microscopy (AFM) platform that uses antibody-antigen capture to routinely isolate and nanomechanically characterize CTCs present in blood samples from prostate cancer patients.

Responses of Acinetobacter baumannii Bound and Loose Extracellular Polymeric Substances to Hyperosmotic Agents Combined with or without Tobramycin: An Atomic Force Microscopy Study.

In this work, contributions of extracellular polymeric substances (EPS) to the nanoscale mechanisms through which the multidrug-resistant Acinetobacter baumannii responds to antimicrobial and hyperosmotic treatments were investigated by atomic force microscopy. Specifically, the adhesion strengths to a control surface of silicon nitride (SiN) and the lengths of bacterial surface biopolymers of bound and loose EPS extracted from A. baumannii biofilms were quantified after individual or synergistic treatments with hyperosmotic agents (NaCl and maltodextrin) and an antibiotic (tobramycin).

The relative composition of actin isoforms regulates cell surface biophysical features and cellular behaviors.

Background: Cell surface mechanics is able to physically and biomechanically affect cell shape and motility, vesicle trafficking and actin dynamics. The biophysical properties of cell surface are strongly influenced by cytoskeletal elements. In mammals, tissue-specific expression of six actin isoforms is thought to confer differential biomechanical properties.

Role of overexpressed CFA/I fimbriae in bacterial swimming.

Enterotoxigenic Escherichia coli CFA/I is a protective antigen and has been overexpressed in bacterial vectors, such as Salmonella Typhimurium H683, to generate vaccines. Effects that overexpressed CFA/I may engender on the bacterial host remain largely unexplored. To investigate, we constructed a high CFA/I expression strain, H683-pC2, and compared it to a low CFA/I expression strain, H683-pC, and to a non-CFA/I expression strain, H683-pY.

Capture efficiency of Escherichia coli in fimbriae-mediated immunoimmobilization.

Capturing pathogens on a sensor surface is one of the most important steps in the design of a biosensor. The efficiency of a biosensor at capturing pathogens has direct bearing on its sensitivity. In this work we investigated the capturing of Escherichia coli on substrates modified with antibodies targeting different types of fimbriae: K88ab (F4), K88ac (F4), K99 (F5), 987P (F6), F41, and CFA/I.

Antibody selection for immobilizing living bacteria.

We report a comparative study of the efficacy of immobilizing living bacteria by means of seven antibodies against bacterial surface antigens associated with Salmonella enterica Serovar Typhimurium. The targeted bacterial antigens were CFA/I fimbriae, flagella, lipopolysaccharides (LPS), and capsular F1 antigen. The best immobilization of S.

Bacteria survive multiple puncturings of their cell walls.

A bacterial cell wall is a highly dynamic multilayer structure interfacing the cytoplasm to the outside environment. It supports a multitude of chemical and biological processes necessary for life. It is therefore postulated that damage to the structure of bacterial cell wall would threaten cell integrity and result in cell death.

Porphyrin as an ideal biomarker in the search for extraterrestrial life.

A key issue in astrobiological research is identifying target molecules that are unambiguously biological in origin and can be easily detected and recognized. We suggest porphyrin derivatives as an ideal target, because these chromophores are global in distribution and found in virtually all living organisms on Earth, including microorganisms that may approximate the early evolution of life on Earth. We discuss the inherent qualities that make porphyrin ideally suited for astrobiological research and discuss methods for detecting porphyrin molecules in terrestrial sedimentary environments.