The Bioanalytical and Biomedical Applications of Polymer Modified Substrates

Extending the Shelf-Life of Immunoassay-Based Microfluidic Chips through Freeze-Drying Sublimation Techniques

Point-of-care testing (POCT) platforms utilizing immunoassay-based microfluidic chips offer a robust and specific method for detecting target antibodies, demonstrating a wide range of applications in various medical and research settings. Despite their versatility and specificity, the adoption of these immunoassay chips in POCT has been limited by their short shelf-life in liquid environments, attributed to the degradation of immobilized antibodies. This technical limitation presents a barrier, particularly for resource-limited settings where long-term storage and functionality are critical. To address this challenge, we introduce a novel freeze-dry sublimation process aimed at extending the shelf-life of these microfluidic chips without compromising their functional integrity. This study elaborates on the mechanisms by which freeze-drying preserves the bioactivity of the immobilized antibodies, thereby maintaining the chip's performance over an extended period. Our findings reveal significant shelf-life extension, making it possible for these POCT platforms to be more widely adopted and practically applied, especially in settings with limited resources. This research paves the way for more accessible, long-lasting, and effective POCT solutions, breaking down previous barriers to adoption and application.

Recent advances in metal-family flame retardants: a review

The use of polymer materials is inextricably linked to our manufacturing life. However, most of them are easily combusted in the air and the combustion process generates a large amount of toxic fumes and dangerous smoke. This can result in injuries and property damage, as well as limiting their use. It is essential to enhance the flame-retardant properties and smoke suppression performance by using multiple flame retardants. Metal-based flame retardants have a unique chemical composition. They are environmentally friendly flame retardants, which can impart good smoke suppression, flame retardancy to polymers and further reduce the production of toxic gases. The differences in the compounds formed between the transition metals and the main group metals make them act differently as flame retardants for polymers. As a result, this study presents the research progress and flame-retardant mechanism of flame-retardant polymers for flame retardants from different groups of metals in the periodic table of elements in a systematic manner. In view of the differences between the main group metals and transition metals, the mechanism of their application in flame retardant polymer materials is carefully detailed, as are their distinct advantages and disadvantages. And ultimately, prospects for the development of transition metals and main group metals are outlined. It is hoped that this paper will provide valuable references and insights for scholars in the field.

Surface modification for improving immunoassay sensitivity

Immunoassays are widely performed in many fields such as biomarker discovery, proteomics, drug development, and clinical diagnosis. There is a growing need for high sensitivity of immunoassays to detect low abundance analytes. As a result, great effort has been made to improve the quality of surfaces, on which the immunoassay is performed. In this review article, we summarize the recent progress in surface modification strategies for improving the sensitivity of immunoassays. The surface modification strategies can be categorized into two groups: antifouling coatings to reduce background noise and nanostructured surfaces to amplify the signals. The first part of the review summarizes the common antifouling coating techniques to prevent nonspecific binding and reduce background noise. The techniques include hydrophilic polymer based self-assembled monomers, polymer brushes, and surface attached hydrogels, and omniphobicity based perfluorinated surfaces. In the second part, some common nanostructured surfaces to amplify the specific detection signals are introduced, including nanoparticle functionalized surfaces, two dimensional (2D) nanoarrays, and 2D nanomaterial coatings. The third part discusses the surface modification techniques for digital immunoassays. In the end, the challenges and the future perspectives of the surface modification techniques for immunoassays are presented.

A Review of Research on the Effect of Temperature on the Properties of Polyurethane Foams

Temperature is one of the main factors affecting the properties of polyurethane foams, and there are large differences in the mechanical properties of polyurethane foams at different temperatures. To understand the effect of temperature on the mechanical properties of polyurethane foams and to provide a theoretical basis for the application of polyurethane foams in extreme environments, this paper systematically describes the research on the effect of mold temperature, raw material temperature, and environmental temperature on the microstructure and mechanical properties of polyurethane foams in the formation and service stages of rigid polyurethane foams by domestic and foreign scholars, and summarizes the effect of temperature on the mechanical properties of polyurethane foams and the mechanism of action. A review of the literature shows that the effect of different temperatures on the mechanical properties of polyurethane foams can be summarized. The literature review shows that there are certain changes in the foaming process, pore structure, and mechanical properties of polyurethane foams at different temperatures, and the increase in temperature generally leads to the increase in pore size, decrease in density, and decrease in mechanical properties of polyurethane foams.

Thermoresponsive and antibacterial two-dimensional polyglycerol-interlocked-polynipam for targeted drug delivery

Two-dimensional polymeric networks are a new class of polymers with interesting physicochemical and biological properties. They promise a wide range of future biomedical applications including pathogen interactions, drug delivery, bioimaging, photothermal, and photodynamic therapy, owing to their unique features, such as high surface area and multivalent interactions at nano-biointerfaces. In this work, a thermosensitive two-dimensional polymeric network consisting poly(N-isopropylacrylamide) (pNIPAM) chains that are mechanically interlocked by a polyglycerol platform was synthesized and used for bacteria incapacitation. Two-dimensional hyperbranched polyglycerol (2D-hPG) was synthesized by a graphene-assisted strategy and used for encapsulation of azobisisobutyronitrile (AIBN). Radical polymerization of N-isopropylacrylamide by encapsulated AIBN resulted in thermoresponsive platforms with ~ 500 nm lateral size and 20-50 nm thickness. Due to its porous structure, 2D-PNPG was able to efficiently load antibiotics, such as tetracycline (TC) and amoxicillin (AMX). The rate of release of antibiotics from 2D-PNPG and the antibacterial activity of the system correlated with the variation of temperature as a result of the thermosensitivity of 2D-PNPG. This study shows that two-dimensional polymers are efficient platforms for future biomedical applications including drug delivery and bacteria incapacitation.

Graphical abstract

Thermoresponsive two-dimensional nanomaterials with the ability of loading therapeutic agents and antibacterial activity are synthesized and characterized.