RSC Applied Polymers最新文献

Stress is a response to stimuli which disrupt the homeostasis of a cell or organism. Adenosine is a purine nucleoside which functions as an immunomodulator and signalling molecule, with elevated levels present in tissues exposed to stress. Current methods used to determine adenosine levels within the body involve chromatography coupled with mass spectrometry, which while sensitive is time consuming and costly, highlighting the need for a quicker and more cost-effective detection method. Six nanoMIPs were produced using solid-phase synthesis targeting adenosine: a plain nano-MIP, an acrylamide-dT nano-MIP (bearing an acrylamide-modified thymidine molecule), and a carboxy-dT nanoMIP (bearing a carboxy-modified thymidine molecule) were made using two different methods. The first involved glutaraldehyde as the linker molecule connecting the template to the solid phase, whilst the second used EDC/NHS coupling chemistry. This allowed us to alter the orientation of the template to present either the base or sugar outwards. SPR was used to test the nanoMIP binding affinities and selectivity against adenosine, thymidine, deoxyguanosine and deoxycytidine. It was found the binding affinities of the nanoMIPs increased with use of the modified thymidine monomers, with equilibrium dissociation constants (K_D) values of the plain nanoMIP, acrylamide-dT nanoMIP and carboxy-dT nanoMIP being 221 nM, 9.35 nM, and 2.11 nM respectively for the glutaraldehyde method. The following K_D values were obtained for the EDC/NHS method: 212 nM, 5430 nM, and 111 nM for the plain nanoMIP, acrylamide-dT nanoMIP and carboxy-dT nano-MIP respectively. This illustrated the glutaraldehyde method produced more effective nanoMIPs than using EDC/NHS. This is surprising as it is counter-intuitive to the imagined Watson–Crick pairing. When challenged with the other nucleosides, excellent selectivity was observed. Fetal bovine serum was used to test the capability of the nanoMIPs in complex matrixes with consistent results produced throughout.

Gut bacteria influence human health by digesting nutrients, modulating immune responses, and communicating with the nervous system. Orally delivered probiotics must survive the harsh environment of stomach acid to reach the gut microbiome and incur a health benefit. Here, the probiotic Lactococcus lactis was encapsulated via coaxial electrospinning into alginate-based nanofibers containing the antacid calcium carbonate. Though the high molecular weight polyethylene oxide was used to facilitate fiber formation, crosslinking the nanofibers in an aqueous solution allowed the polyethylene oxide to diffuse out of the nanofiber to form a safe for oral consumption formulation. The antacid protected the encapsulated living bacteria against acidic insults; thus, bacteria remained viable and encapsulated during submersion in a simulated stomach model. After transfer to the intestinal phase, up to 120 000 viable probiotic cells were released per gram of nanofibers demonstrating the pH-dependent delivery of the electrospun alginate nanofibers.

Ionic polymer metal composites (IPMCs) are a versatile class of ionic polymer-based transducers with excellent electromechanical properties and wide application potential in the fields of bionic robots, medical devices and wearable devices as actuators and sensors. In this perspective, we discuss the development of polymer matrices and applications of IPMCs, from actuating to multifunctional sensing. The latest ionic polymer matrixes for IPMCs show the trend toward being printable, programmable and degradable, which will facilitate multi-scenario applications of IPMCs. Regarding the applications, IPMCs have been widely used in various fields as actuators and multi-parameter sensors, and related devices will be further developed in the direction of miniaturization, integration and intelligence. Furthermore, some suggestions are put forward to facilitate the further development and wide application of IPMCs.

Polycations are scalable and affordable nanocarriers for delivering therapeutic nucleic acids. Yet, cationicity-dependent tradeoffs between nucleic acid delivery efficiency, cytotoxicity, and serum stability hinder clinical translation. Typically, the most efficient polycationic vehicles also tend to be the most toxic. For lipophilic polycations—which recruit hydrophobic interactions in addition to electrostatic interactions to bind and deliver nucleic acids—extensive chemical or architectural modifications sometimes fail to resolve intractable toxicity—efficiency tradeoffs. Here, we employ a facile post-synthetic polyplex surface modification strategy wherein poly(L-glutamic acid) (PGA) rescues toxicity, inhibits hemolysis, and prevents serum inhibition of lipophilic polycation-mediated plasmid (pDNA) delivery. Importantly, the sequence in which polycations, pDNA, and PGA are combined dictates pDNA conformations and spatial distribution. Circular dichroism spectroscopy reveals that PGA must be added last to polyplexes assembled from lipophilic polycations and pDNA; else, PGA will disrupt polycation-mediated pDNA condensation. Although PGA did not mitigate toxicity caused by hydrophilic PEI-based polycations, PGA tripled the population of transfected viable cells for lipophilic polycations. Non-specific adsorption of serum proteins abrogated pDNA delivery mediated by lipophilic polycations; however, PGA-coated polyplexes proved more serum-tolerant than uncoated polyplexes. Despite lower cellular uptake than uncoated polyplexes, PGA-coated polyplexes were imported into nuclei at higher rates. PGA also silenced the hemolytic activity of lipophilic polycations. Our work provides fundamental insights into how polyanionic coatings such as PGA transform intermolecular interactions between lipophilic polycations, nucleic acids, and serum proteins, and facilitate gentle yet efficient transgene delivery.

The photoresist is one of the key materials for the development of the modern semiconductor industry, and it not only affects the chip manufacturing process but also has an important impact on performance. Photoresists with low dielectric properties have a critical impact on the fabrication process and performance of various chips and devices. In this paper, a silicone encapsulated photoresist with low dielectric properties is reported, and it demonstrates excellent film-forming properties and lithography patterning effects, with a line width of 10 μm and a line spacing, a low dielectric constant (D_k = 2.75), a high thermal decomposition temperature (T₅ = 503.5 °C), a low coefficient of thermal expansion (CTE = 33.61 ppm per °C), and excellent mechanical properties of thin films. This type of resin has a photo-crosslinked double bond structure and a thermally cross-linked benzocyclobutene structure, in which the silicone branched structure gives the photoresist excellent patterning properties and the thermally crosslinked structure gives the film excellent thermal, electrical, and mechanical properties. The resin is expected to replace traditional polyimide photoresists and has important applications in the semiconductor industry.

Secondary electromagnetic pollution generated due to the inevitable reflection in solid/thin film conducting polymer composites has been a major barrier in realizing high-performance absorption-dominated electromagnetic interference (EMI) shielding. In the past, prodigious efforts were made to minimize the reflection by tailoring the impedance characteristics between the air and the substrate. For instance, incorporation of a microcellular scaffold (3D structure) such as foam and aerogel in a polymer matrix have been extensively investigated to tailor the surface impedance matching and achieve enhanced absorption. To date, application of the 3D graphene microcellular scaffold alone or its hybrid with other magnetic, conductive, and dielectric materials has been continuously pursued to diminish reflectivity and increase absorption via the dielectric and interfacial relaxation loss mechanism. An aerogel and foam structure contains multiscale pores (micro and nano scale pores). Through the large number of solid/air interfaces created by such pores, it can efficiently tune the impedance matching. The solid/air interface renders surplus EM wave attenuation capabilities by increasing the EM wave trajectory path via internal scattering within the pores. The 3D graphene architectures-based polymer composites show hitherto EMI shielding efficiency improvement at significantly low mass density and percolation threshold. However, most of the existing studies on 3D graphene-based composites rely on trial-and-error methods without comprehensively investigating the effect of the geometrical and microstructures aspects on the EMI shielding performance. Furthermore, the state-of-art literature does not (re)present an analytical/theoretical model that can be employed to optimize parameters appropriate for designing the absorption-dominated shielding material with diminished reflection. This review is intended to cover the latest progress and innovation around 3D graphene nanostructure-based polymer composites as EMI shielding materials. The EMI shielding properties of the composites, including graphene aerogels, foam and hybrid aerogel/foam, with other dielectric and magnetic materials are discussed along with the underlying mechanism. In addition, this review represents an input impedance model that can be utilized in conjunction with experimental design to optimize geometrical and microstructural parameters to realize an absorption-dominated shielding material. Based on the available status on 3D graphene scaffold-based composites, we summarize the current achievements and offer a route toward future developments.

The periodontium is one of the most complex tissues in the body because its structure is formed by a hierarchical combination of soft and hard tissues. Due to its complex architecture, the treatment and regeneration of damaged periodontal tissue caused by diseases is still a challenge in biomedicine. The most common disease of the periodontium is periodontitis, which occurs when the periodontium becomes infected and inflamed as a bacterial biofilm forms in the mouth. Recently, various biocompatible biomaterials made of natural and synthetic polymers have been developed for periodontal tissue regeneration or treatment due to their superior properties such as controlled drug and bioactive molecule delivery, mimicking the 3D network of tissue, biocompatibility, antibacterial and mechanical properties. In particular, biomaterials designed for drug delivery, such as hydrogels, scaffolds, films, membranes, micro/nanoparticles and fibers, and additively manufactured biomaterials have undergone in vitro and in vivo testing to confirm their potential clinical utility in periodontal regeneration and periodontitis treatment. This review explores recent advances in the use of biomaterials for the prevention and/or treatment of periodontal regeneration and periodontitis. Specifically, it emphasizes advancements in drug/biomolecule delivery and the use of additively manufactured biomaterials for addressing periodontal issues.

The technological world has undergone significant progress over the last 60 years through advances in electronics; nonetheless, a lot needs to be accomplished for constructing devices that can toggle between desired functions. This review provides a brief look at recent developments in innovative chemistries involving fine-tuning the molecular properties of polymerized ionic liquids to create new kinds of responsive organic electronic devices, thus highlighting the versatility of polymerized ionic liquids in promising a bright future for advanced organic electronics. This review also reinforces the need to customize materials for contemporary applications, as doing so can improve the functionality of sophisticated devices. In addition, the review sheds light on a novel class of materials referred to as “doubly polymerized ionic liquids”. This class of materials features negligible ionic conductivity, providing a solid groundwork for constructing ion-locked devices that can be used to attain novel technological applications. We anticipate this review will close research gaps and promote discoveries in the fields of organic electronics, polymer chemistry, and polymer physics.

Ceramic-based ferroelectric materials have long been used as functional ferroelectric materials for applications in triboelectric-energy harvesting. However, their drawbacks (brittleness, energy-intensive fabrication methods, and minimal mechanical flexibility) have intensified the search for alternatives where flexible form factors are needed. Molecular ferroelectrics are an emerging class of multifunctional materials. To date, the intriguing piezo/ferroelectric properties of these materials have led to the construction of piezoelectric nanogenerators. However, their numerous advantages warrant their expansion towards triboelectric nanogenerators (TENGs). We aimed to demonstrate the potential of a molecular ferroelectric, diisopropylammonium bromide (DIPAB), in the realm of triboelectric-energy harvesting. Combining ferroelectric properties with enhanced surface modification, we designed an electrospun-based TENG comprising DIPAB/P(VDF-TrFE) as an active negative layer. The synergistic effects emanating from highly aligned polymeric chains and ferroelectric particles in conjunction with a high surface area of the as-designed TENG generated an output voltage of 203.8 V and resulted in a maximum power density of 416.2 mW m⁻² when operated in contact separation mode. Its practical application as a sustainable power supply for low-power electronics was demonstrated through powering of commercial electrolytic capacitors and LEDs. This study presents a reliable, cost-effective, and readily scalable method for enhancing TENG performance. This strategy holds potential for application of TENGs in wearable biomechanical-energy harvesting, and paves the way for further advances involving a sustainable energy solution for wearable electronics.

Free-form creation of 3-dimensional (3D) structures, such as in additive manufacturing (AM) and 3D printing (3DP), typically requires a direct line-of-sight or physical contact between an energy source and a build material. By stepping away from this equipment paradigm, we discovered a method to achieve 3D composites inside of opaque, open-cell foams that enables unprecedented access to bicontinuous, interlocked composite structures. We found that high-intensity focused ultrasound (HIFU) provided efficient, localized heating at a focal point that could be spatially controlled within a foam matrix. Foam specimens were infused with thermally curable acrylate resin formulations, which enabled free-form creation of 3D structures as the HIFU focal point was moved throughout the interior of the foam. The 3D structure was created entirely based upon the toolpath, without any build plate or inherently sequenced layer-by-layer processes. Since the foam and cured resin were mechanically interlocked in the process, HIFU curing achieved bicontinuous composites seemingly independent of surface compatibilities between the foam and resin. Starting with commercially available polyurethane foams, we investigated combinations with different resin systems to achieve a range of mechanical properties from the final composite structures. For example, using poly(ethylene glycol) diacrylate (PEGDA) resulted in stiff, hard composite domains within the foam, whereas resins comprising 2-hydroxyethyl acrylate (HEA) led to soft, elastomeric composite structures. Multimaterial composites were also achieved, simply by displacing uncured resin from the foam and exchanging it with a different resin formulation. Control over the shape and orientation of internal structural features within the foam scaffolds also enabled controllable anisotropic mechanical responses from the composites.