Polymer Nanostructures Research Articles

Polymeric nanoparticles for protein and peptide delivery

Protein- and peptide-based medications are recognized for their effectiveness and lower toxicity compared to chemical-based drugs, making them promising therapeutic agents. However, their application has been limited by numerous delivery challenges. Polymeric nanostructures have emerged as effective tools for protein delivery due to their versatility and customizability. Polymers’ inherent adaptability makes them ideal for meeting the specific demands of protein-delivery systems. Various strategies have been employed, such as enzyme inhibitors, absorption enhancers, mucoadhesive polymers, and chemical modifications of proteins or peptides. This study explores the hurdles associated with protein and peptide transport, the use of polymeric nanocarriers (both natural and synthetic) to overcome these challenges, and the techniques for fabricating and characterizing nanoparticles.

Retraction Note: Metal-ion-directed synthesis of two nanostructured coordination polymers: topological diversity and growth inhibition of human glioma cells

Retraction Note: Metal-ion-directed synthesis of two nanostructured coordination polymers: topological diversity and growth inhibition of human glioma cells

Multilayer architected polymer nanostructure for microwave absorber-based EMI shielding

Reflection-based electromagnetic interference shielding materials, though effectively stop the radiation, redirect the interference to nearby electronic devices, creating secondary pollution. In this sense, it is better to use absorption-dominant lightweight and flexible materials with high shielding effectiveness. This paper reports the fabrication of a multilayered polymer nanocomposite for enhancing electromagnetic interference shielding applications through absorption. By using a doctor-blade technique, three individual layers of poly(vinylidene fluoride) based polymer nanocomposite, each with different fillers, were prepared and stacked together to form a 3 mm thick multilayered (four-layer) composite. The fillers were 5% Ag-decorated graphene nanoplatelets, acid-functionalized MWCNT, and barium hexaferrite. Between 8 and 18 GHz, this multilayered composite absorbs a maximum of 90% of incident microwave radiation, resulting in a shielding in the range of 20–45 dB. This structure is very useful for developing flat and lightweight absorbers. For comparison, a homogeneously prepared nanocomposite comprising all these three fillers is found to give a shielding of around 53 dB with a reflection ranging between 78% and 89%.

Directing Organometallic Ring-Chain Equilibrium by Electrostatic Interactions.

Dynamic chemistry, which falls into the realm of both supramolecular and covalent chemistry, enables intriguing properties, such as structural diversity, self-healing, and adaptability. Due to robustness of covalent bonds compared to noncovalent ones, dynamic covalent chemistry has been exploited to synthesize complex molecular nanostructures at solid/liquid interfaces under ambient conditions, generally responsive to internal factors that directly regulate intermolecular covalent bonds. However, directing dynamics of covalent nanostructures, e.g., the typical ring-chain equilibria, on surface by extrinsic interactions remains elusive and challenging. Herein, we have controllably directed the ring-chain equilibrium of covalent organometallic structures by regulating intermolecular electrostatic interactions, thus achieving on-surface dynamic covalent chemistry under ultrahigh vacuum conditions. Our findings unravel the dynamic mechanism of covalent polymers governed by weak intermolecular interactions at the submolecular level, which not only bridges the gap between supramolecular and covalent chemistry but also offers great opportunities for the fabrication of adaptive polymeric nanostructures that respond to different conditions.

Homochiral “8″-shaped nanotoroids assembled from polypeptides

Figure eight-shaped (“8″-shaped) nanotoroids have been observed in DNA and proteins, however, they are rarely reported in synthetic polymer systems. Reported here is the formation of homochiral “8″-shaped nanotoroids from poly(γ-benzyl glutamate) (PBG) homopolymers. The L-type and D-type PBGs, i.e., PBLG and PBDG respectively, form left-handed and right-handed “8″-shaped chiral nanotoroids. The formation of the nanotoroids is achieved in a two-step route. Nanofibers are first self-assembled by the PBG homopolymers, which, with changing solvent nature, break into short nanofibers and twist into “8″-shaped nanotoroids. In such processes, the pendant phenyl groups of PBGs change from an extended to a contract form, which generates the internal stress driving the transition of nanofibers to “8″-shaped nanotoroids. This work not only enriches the topology and preparation method of nanotoroids, but also enhances our ability in controlling polymer nanostructures.

Solid‐State Revolution: Assessing the Potential of Solid Polymer Electrolytes in Lithium‐Ion Batteries

AbstractLithium‐ion batteries (LIBs) are crucial for achieving sustainable energy goals due to their high energy density and long cycle life. They dominate markets like consumer electronics, electric vehicles, and stationary energy storage systems. However, current LIBs use liquid electrolytes, which are toxic, flammable, and their liquid state does not resist dendrite growth, causing battery capacity decline and failure. Additionally, the limited availability of lithium and other metals makes liquid‐based LIBs less sustainable. On the other hand, solid polymer electrolytes (SPEs) offer a safer alternative as they are non‐volatile and can resist dendrite growth. However, ion transport in solids is much more restricted than in liquids, while imperfect solid‐solid interfaces contribute to interfacial resistance leading to lower ionic conductivity and increasing Ohmic losses or requiring battery operation at elevated temperatures. Chemical and mechanical degradation of these interfaces can also result in battery capacity fade, and poorer cyclic performance compared to liquid electrolytes. Understanding the ionic transport mechanisms in SPEs is critical for designing and optimizing the nanostructure of polymers and polymer/electrode interfaces to overcome these limitations. In this review, the fundamental mechanisms of ion transport in SPEs will first be explored. Various state‐of‐the‐art approaches for addressing the key challenges in SPEs and their solutions are then discussed. Furthermore, the current status of SPEs is analyzed to determine their potential for replacing liquid electrolytes in the future.

Semibatch and Continuous Electrohydrodynamic Mixing Nanoprecipitation for Scalable Polymer Nanostructure Production

Semibatch and Continuous Electrohydrodynamic Mixing Nanoprecipitation for Scalable Polymer Nanostructure Production

LOCAL DIELECTRIC SPECTROSCOPY AND ITS APPLICATION TO POLYMERS

ABSTRACT The advent of nanodielectrics, nanocomposite materials based on a polymeric matrix, and materials with physical properties ruled by interfacial effects in general demands techniques to characterize functional properties on a local scale with high spatial resolution. Scanning probe microscopies (SPMs), in their electrical modes, have emerged as indispensable tools to access physical quantities such as dielectric constant, surface potential, and static charge, with nanometer-scale lateral resolution and with surface selectivity, being influenced mainly by the outermost layer of the specimen. In this tribute, the development of various SPM electrical modes is illustrated, focusing on the measurement of dielectric permittivity and its spectroscopic extension to access the local, frequency-dependent dielectric function (local dielectric spectroscopy [LDS]). The application to nanostructured polymers in the form of ultrathin films, nanometer-scale–separated blends, and self-assembled block copolymer structures is described. LDS appears to be a promising technique for characterizing the electric properties of polymers and their composites as well as other glass formers and nanostructured systems.

The Transformative Role of Nano-SiO2 in Polymer Electrolytes for Enhanced Energy Storage Solutions

In lithium–polymer batteries, the electrolyte is an essential component that plays a crucial role in ion transport and has a substantial impact on the battery’s overall performance, stability, and efficiency. This article presents a detailed study on developing nanostructured composite polymer electrolytes (NCPEs), prepared using the solvent casting technique. The materials selected for this investigation include poly(vinyl chloride) (PVC) as the host polymer, lithium bromide (LiBr) as the salt, and silica (SiO2) as the nanofiller. The addition of nano-SiO2 dramatically enhanced the ionic conductivity of the electrolytes, with the highest value of 6.2 × 10−5 Scm−1 observed for the sample containing 7.5 wt% nano-SiO2. This improvement is attributed to an increased amorphicity resulting from the interactions between the polymer, salt, and filler components. A structural analysis of the prepared NCPEs using X-ray diffraction revealed the presence of both crystalline and amorphous phases, further validating the enhanced ionic transport. Additionally, the thermal stability of the NCPEs was found to be excellent, withstanding temperatures up to 334 °C, thereby reinforcing their potential application in lithium–polymer batteries. This work explores the electrochemical performance of a fabricated lithium-ion-conducting primary electrochemical cell (Zn + ZnSO4·7H2O|PVC: LiBr: SiO2|PbO2 + V2O5), which demonstrated an open circuit voltage of 2.15 V. The discharge characteristics of the fabricated cell were thoroughly studied, showcasing the promising potential of these NCPEs. With the support of superior morphological and electrical properties, as-prepared electrolytes offer an effective pathway for future advancements in lithium–polymer battery technology, making them a highly viable candidate for enhanced energy storage solutions.

Predicting protracted binding kinetics of polymers: Integral of first-passage times.

Capturing protracted binding kinetics of polymers onto the surface of nanoobjects is crucial for the rational design of multifunctional nanostructures, such as patchy nanoparticles and nanodrug carriers. Recently, we developed a method-integral of first-passage times (IFS)-to successfully predict nonequilibrium, kinetically stable superstructures fabricated by two star polymers. However, whether the protracted binding kinetics predicted by IFS corresponds to the actual polymer adsorption has only been incompletely explored. In this paper, we clarify this issue by using IFS to study polymer adsorption with binding ends onto a planar wall as an example. At low free-energy barriers, the IFS-predicted polymer binding kinetics is consistent with those extracted from direct simulations. At high free-energy barriers, the protracted polymer adsorption predicted by IFS coincides with those measured in experiments. Our findings demonstrate the feasibility of IFS to study long-lived formation kinetics of polymer nanostructures by spanning timescales from picoseconds to macroscopic minutes, which establishes a foundation to use IFS in different applications.

Building Therapies Layer-by-Layer: 2024 Benjamin Franklin Medal in Chemistry presented to Paula T. Hammond, Ph.D

The field of polymer science and materials engineering is advancing with new assembly processes that allow for the implementation of nanoscale structures and orders at a more affordable cost. Layer-by-layer (LbL) adsorption, which was introduced 30 years ago, has revolutionized the understanding and application of electrostatic assembly. This has resulted in a rapid expansion of the field, generating new scientific insights and engineering applications. Chemical engineers have mainly explored its use in reactive and passive membranes, drug delivery systems, and electrochemical and sensing devices. The 2024 Franklin Medal Laureate Professor Paula T. Hammond has been at the forefront of this progress.Professor Paula T. Hammond has been instrumental in the advancement of this field since its inception. The LbL method allows for the sequential and precise assembly of different charged species, from molecules and polymers to colloidal and nano-to-microscale materials. The assembly is driven by alternating charge interactions or complementary bonding, such as hydrogen bonding. LbL offers unprecedented control over materials selection, properties, and architecture by alternatingly adsorbing oppositely charged species from aqueous solutions. This near-molecular control enables the design of functional materials with widely tunable structural, optical, electrical, and chemical properties. The ability to incorporate an array of building blocks into nanoscale thin films allows for control of film composition across its thickness, which is crucial for many emerging applications. Engineering opportunities span biology, medicine, energy conversion, storage (fuel cells, batteries, electrochromic devices, and solar cells), and sensors.Professor Paula T. Hammond is recognized for being at the forefront of developing LbL and related electrostatic polymer assembly techniques that create entire families of nanostructured polymer and composite systems. Her innovative materials display outstanding static properties as well as a range of dynamic (environmentally responsive) properties. LbL offers a multitude of advantages for biological applications and excels in its impact on drug delivery. Cytocompatibility, engineering the drug loading versatility, film stability, and protecting the payload and its controlled release are paramount for the successful translation of LbL drug delivery systems.Professor Hammond has translated her scientific insights into practical applications in medicine and sustainable energy, nurturing their commercial exploration, expanding their technical impact, and inspiring a generation of soft matter nanomaterials scientists and engineers.

Nanocarrier-Based Delivery Approaches of Mangiferin: An Updated Review on Leveraging Biopharmaceutical Characteristics of the Bioactive.

In recent years, bioactive constituents from plants have been investigated as an alternative to synthetic approaches of therapeutics. Mangiferin (MGF) is a xanthone glycoside extracted from Mangifera indica and has shown numerous medicinal properties, such as antimicrobial, anti-diarrhoeal, antiviral, anti-inflammatory, antihypertensive, anti-tumours, and anti-diabetic effects. However, there are numerous challenges to its effective therapeutic usage, including its low water solubility, limited absorption, and poor bioavailability. Nano formulation approaches in recent years exhibited potential for the delivery of phytoconstituents with key benefits of high entrapment, sustained release, enhanced solubility, stability, improved pharmacokinetics, and site-specific drug delivery. Numerous techniques have been employed for the fabrication of MGF-loaded Nano formulations, and each technique has its advantages and limitations. The nanocarriers that have been employed to fabricate MGF nanoformulations for various therapeutic purposes include; polymeric nanoparticles, nanostructure, lipid carriers, polymeric micelles, Nano emulsions, microemulsion & self-microemulsifying drug delivery system, solid lipid nanoparticles, gold nanoparticles, carbon nanotubes, transfersomes, nanoliposomes, ethosomes & transethosomes, and glycethosomes. Different biopharmaceutical characteristics (size, shape, entrapment efficiency, zeta potential, in vitro drug release, ex vivo drug permeation,, and in vivo studies) of the mentioned MGF-loaded nanocarriers have been methodically discussed. Patent reports are also included to further strengthen the potential of MGF in the management of diseases.

Direct Laser Writing of Micro-Nano Filters Based on Three-Photon Polymerization.

Direct laser writing (DLW) enables the manufacturing of functional quantum dot (QD)-polymer nanostructures with the special performance desired for technological applications. However, most papers fabricate the QD-polymer photoresist based on the principle of two-photon polymerization using laser wavelengths of 750-800 nm, which cannot effectively fabricate the near-infrared QD-polymer photoresist with absorption wavelengths above 800 nm due to linear absorption. Moreover, most papers report a relatively low doping concentration of QDs. To address these issues, this study introduces three-photon DLW technology using a near-infrared 1035 nm laser to effectively avoid the linear absorption of the near-infrared PbS/CdS QD-polymer photoresist. Three kinds of QD-polymer photoresists with concentrations up to 150 mg mL-1 are prepared through surface modification of QDs. We demonstrate that three-photon DLW is feasible to fabricate high-concentration QD-polymer photoresist to produce micro/nano high-performance QD-polymer filters of visible and near-infrared light absorption. This study provides materials and process guidance for the fabrication and application of visible and near-infrared optical filters through three-photon DLW processing of various kinds of functional nanoparticles-polymer photoresist.

Hierarchically Micro- and Nanostructured Polymer via Crystallinity Alteration for Sustainable Environmental Cooling.

Cooling environments are a pervasive need in our society, with conventional air conditioners being the most popular approach. However, air conditioners rely heavily on electricity and Freon, a chemical that depletes ozone and contributes to greenhouse gas effects. To address this issue, passive daytime radiative coolers (PDRCs) have been proposed to achieve cooling by simultaneously reflecting sunlight and allowing internal heat to escape without electricity. Despite their potential, most high-performance PDRCs are composed of thick polymer films, which increases material costs during PDRC preparation and limits thermal transport. In this work, we introduced an economical and scalable solvent evaporation-based method to prepare a relatively thin hierarchically micro- and nanostructured poly(vinylidene fluoride-trifluoroethylene) via crystallinity alteration. Particularly, we find that the key to generating nanosized pores is to remove the water residual within the film without sample annealing, which significantly enhances the scattering efficiency across the solar spectrum. With our design, we demonstrate effective cooling of the outdoor environment, achieving a cooling temperature of Δ2.5 °C, with a film thickness of only 215 μm. Furthermore, our model suggested that applying this material could lead to annual energy savings of up to ∼39% in warmer climates across the country and up to 715 GJ nationwide. Developing effective PDRCs with reduced material thickness, such as the one discussed here, is imperative for implementing sustainable cooling solutions and reducing our carbon footprint.

Charging dependent electro-chemo-mechanical coupling behavior of polymer electrolytes containing immobilized anions

Theoretical models have been developed to explore the electrodeposition stability between Li metal and salt-doped polymer electrolytes. However, there is still limited investigation on the coupling behavior between mechanics and electrochemistry in those novel nano-structured polymers with immobilized anions. In this work, we employ a multiphysics modeling framework to predict the electro-chemo-mechanical behavior of polymer electrolytes containing immobilized anions. We analyze the impacts of charging conditions, stress coupling and the immobilization of anions on their ion transport, electrical and mechanical properties during charging. Strengthening stress coupling is demonstrated to improve the diffusion-driven stability of electrodeposition, by enhancing limiting applied current densities. Compared with stress coupling, immobilizing anions surprisingly sustains the non-zero interfacial Li+-ion concentrations even at high applied currents, thereby mitigating the potential diffusion-driven instability of electrodeposition. Both stress/strain and overpotentials also get reduces with increasing the concentrations of immobilized anions. This theoretical work provides insights into the strategy of redesigning polymer electrolytes, and also lays foundation for the multiphysics modeling of electrodes and full-cell battery systems.

Nanocomposites of ferrocenyl-modified gold clusters and semiconducting polymers that integrate field-effect transistor and flash memory in a single neuromorphic device

We demonstrate that electroactive thin films incorporating semiconducting polymers and deterministic functionalized gold nanoclusters (ncAu25) lead to the integration of the functions of resistive memory device and field-effect transistor within a single component (“mem-transistor”) in a neuromorphic system. Memristor functions originate from ferrocenyl-modified gold nanoclusters (ncAu25-Fc) embedded in polymethyl-methacrylate (PMMA) and devices optimized for maximum 1/0 “flash” memory effect are found to contain 15 wt. % ncAu25-Fc. Integrated memristor and neuromorphic functions are obtained by replacing PMMA with poly(3-hexylthiophene) (P3HT) in the active layer, from which transistor effects are derived. Based on the energy band diagrams of ncAu25, PMMA, and P3HT, percolation theory is used to explain the memristor 1/0 on/off ratio as a function of ncAu25-Fc concentration. The use of ncAu25-Fc with charge-tunable, ferrocene-modified ligands is critical to achieve better cluster–polymer interfaces. Our work shows that nanostructures of polymers and metalorganic frameworks bear strong potential in the field of neuromorphic devices and circuital simplification of data storage technology.

Berberine and berberine nanoformulations in cancer therapy: Focusing on lung cancer.

Lung cancer is the second most prevalent cancer and ranks first in cancer-related death worldwide. Due to the resistance development to conventional cancer therapy strategies, including chemotherapy, radiotherapy, targeted therapy, and immunotherapy, various natural products and their extracts have been revealed as alternatives. Berberine (BBR), which is present in the stem, root, and bark of various trees, could exert anticancer activities by regulating tumor cell proliferation, apoptosis, autophagy, metastasis, angiogenesis, and immune responses via modulating several signaling pathways within the tumor microenvironment. Due to its poor water solubility, poor pharmacokinetics/bioavailability profile, and extensive p-glycoprotein-dependent efflux, BBR application in (pre) clinical studies is restricted. To overcome these limitations, BBR can be encapsulated in nanoparticle (NP)-based drug delivery systems, as monotherapy or combinational therapy, and improve BBR therapeutic efficacy. Nanoformulations also facilitate the selective delivery of BBR into lung cancer cells. In addition to the anticancer activities of BBR, especially in lung cancer, here we reviewed the BBR nanoformulations, including polymeric NPs, metal-based NPs, carbon nanostructures, and others, in the treatment of lung cancer.

Cyclodextrin Nanosponges: A Revolutionary Drug Delivery Strategy.

Nanosponges are porous solid cross-linked polymeric nanostructures. This study focuses on cyclodextrin-based nanosponges. Nanosponges based on cyclodextrin can form interactions with various lipophilic or hydrophilic compounds. The release of the entrapped molecules can be altered by altering the structure to obtain either a longer or faster release kinetics. The nanosponges might increase the aqueous solubility of weakly water-soluble compounds, develop long-lasting delivery systems, or construct novel drug carriers for nanomedicine. CD-NS (cyclodextrin-based nanosponges) are evolving as flexible and promising nanomaterials for medication administration, sensing, and environmental cleanup. CD-NS are three-dimensional porous structures of cyclodextrin molecules cross-linked by a suitable polymeric network, resulting in a large surface area. This overview covers CD-NS synthesis methods and applications.

Self-Assembly of Hydrophobic Hyperbranched PLMA Homopolymer with -COOH End Groups as Effective Nanocarriers for Bioimaging Applications.

Nanomedicine is a discipline of medicine that applies all aspects of nanotechnology strategies and concepts for treatment and screening possibilities. Synthetic polymer nanostructures are among the many nanomedicine formulations frequently studied for their potential as vectors. Bioimaging is a valuable diagnostic tool, thus, there is always a demand for new excipients/nanocarriers. In this study, hydrophobic hyperbranched poly(lauryl methacrylate) (PLMA) homopolymers comprised of highly hydrophobic LMA moieties with -COOH polar end groups were synthesized by employing reversible addition-fragmentation chain transfer (RAFT) polymerization. Ethylene glycol dimethacrylate (EGDMA) was utilized as the branching agent. End groups are incorporated through the RAFT agent utilized. The resulting amphiphilic hyperbranched polymer was molecularly characterized by size exclusion chromatography (SEC), Fourier transformation infrared spectroscopy (FT-IR), and 1H-NMR spectroscopy. Pyrene, curcumin, and IR-1048 dye were hydrophobic payload molecules successfully encapsulated to show how adaptable these homopolymer nanoparticles (prepared by nanoprecipitation in water) are as dye nanocarriers. This study demonstrates a simple way of producing excipients by generating polymeric nanoparticles from an amphiphilic, hyperbranched, hydrophobic homopolymer, with a low fraction of polar end groups, for bioimaging purposes.

Polymer Microspheres Carrying Schiff-Base Ligands for Metal Ion Adsorption Obtained via Pickering Emulsion Polymerization

Several traditional methods for producing polymer microparticle adsorbents for metal ions exist, such as bulk polymerization followed by milling and crushing the material to micron-size particles, precipitation from organic solvents, and suspension polymerization utilizing surfactants. Alternative methods that are easily scalable and are environmentally friendly are in high demand. This study employs Pickering Emulsion Polymerization Technology (PEmPTech) to synthesize nanostructured polymer microspheres that incorporate Schiff-base ligands, which can be utilized for metal ion adsorption, and specifically Cu(II) ions. Our innovative approach makes use of nanoparticle-stabilized, surfactant-free emulsions/suspensions, enabling the straightforward production of ligand-bearing microspheres while allowing for the precise modulation of the polymer matrix chemistry to maximize adsorption capacities. Through this method, we demonstrate notable enhancements in Cu(II) ion adsorption, which correlates with both the polarity of the monomers used and the concentration of Schiff-base ligands within the microspheres. Notably, our results offer insights into the structure–activity relationships essential for designing tailored adsorbents. This work provides a scalable method to produce high-performance adsorbents and also contributes to sustainable methodologies by excluding harmful surfactants and solvents.