Aerogels are one of the most interesting materials of the 21st century owing to their high porosity, low density, and large available surface area. Historically, aerogels have been used for highly efficient insulation and niche applications, such as interstellar particle capture. Recently, aerogels have made their way into the composite universe. By coupling nanomaterial with a variety of matrix materials, lightweight, high-performance composite aerogels have been developed for applications ranging from lithium-ion batteries to tissue engineering materials. In this paper, the current status of aerogel composites based on nanomaterials is reviewed and their application in environmental remediation, energy storage, controlled drug delivery, tissue engineering, and biosensing are discussed.
Nanoparticle-mediated cancer drug delivery remains an inefficient process. The protein corona formed on nanoparticles (NPs) controls their biological identity and, if optimized, could enhance cancer cell uptake. In this study, a hyperbranched polyester polymer (HBPE) was synthesized from diethyl malonate and used to generate NPs that were subsequently coated with normal sera (NS) collected from mice. Cellular uptake of NStreated HBPE-NPs was compared to PEGylated HBPE-NPs and was assessed using MDA-MB-231 triple-negative breast cancer (TNBC) cells as well as endothelial and monocytic cell lines. NStreated HBPE-NPs were taken up by TNBC cells more efficiently than PEGylated HBPE-NPs, while evasion of monocyte uptake was comparable. NS coatings facilitated cancer cell uptake of HBPE-NPs, even after prior interaction of the particles with an endothelial layer. NS-treated HBPE-NPs were not inherently toxic, did not induce the migration of endothelial cells that could lead to angiogenesis, and could efficiently deliver cytotoxic doses of paclitaxel (taxol) to TNBC cells. These findings suggest that HBPE-NPs may adsorb select sera proteins that improve uptake by cancer cells, and such NPs could be used to advance the discovery of novel factors that improve the bioavailability and tissue distribution of drugloaded polymeric NPs.
The ability to rapidly detect and diagnose acute viral infections is crucial for infectious disease control and management. Serology testing for the presence of virus-elicited antibodies in blood is one of the methods used commonly for clinical diagnosis of viral infections. However, standard serology-based tests have a significant limitation: they cannot easily distinguish active from past, historical infections. As a result, it is difficult to determine whether a patient is currently infected with a virus or not, and on an optimal course of action, based off of positive serology testing responses. Here, we report a nanoparticle-enabled blood test that can help overcome this major challenge. The new test is based on the analysis of virus-elicited immunoglobulin G (IgG) antibody present in the protein corona of a gold nanoparticle surface upon mixing the gold nanoparticles with blood sera. Studies conducted on mouse models of influenza A virus infection show that the test gives positive responses only in the presence of a recent acute viral infection, approximately between day 14 and day 21 following the infection, and becomes negative thereafter. When used together with the traditional serology testing, the nanoparticle test can determine clearly whether a positive serology response is due to a recent or historical viral infection. This new blood test can provide critical clinical information needed to optimize further treatment and/or to determine if further quarantining should be continued.
Nanoalloys or alloy nanoparticles containing multiple metals are of great interest because the combination of multiple metals in close proximity can grant enhanced properties including stability, activity, and selectivity arising from synergism that cannot be accessed by the combination of individual metals. In this study, we have produced nanoalloys in stable flexible electrospun hydrogel nanofibers composed of poly(acrylic acid) and poly(allylamine hydrochloride). The hydrogel fibers were loaded with metal ions such as copper and silver through an immersion in metal salt solutions followed by a chemical reduction to form the metal nanoparticles. The hydrogel matrix allowed for the absorption of metal ions into the fibers and provided a viscous environment to promote the formation of alloy particles in the small diameter range (<25 nm). The proposed fabrication process is advantageous in terms of simplicity, controllability, and versatility. The reductions of 4-nitrophenol and methylene blue were performed to test and compare the catalytic activity of monometallic nanoparticles and copper−silver bimetallic nanoparticles. The copper−silver bimetallic nanoparticles demonstrated preferred selectivity for the reduction of 4-nitrophenol and higher catalytic activity for the reduction of methylene blue. Overall, we have developed promising stable flexible nanocomposites for catalytic reduction of organic redox compounds, and other catalytic nanoalloy systems could be further studied by modification of the procedure.
Polyelectrolyte hydrogel fibers can mimic the extracellular matrix and be used for tissue scaffolding. Mechanical properties of polyelectrolyte nanofibers are crucial in manipulating cell behavior, which metal ions have been found to enable tuning. While metal ions play an important role in manipulating the mechanical properties of the fibers, evaluating the mechanical properties of a single hydrated hydrogel fiber remains a challenging task and a more detailed understanding of how ions modulate the mechanical properties of individual polyelectrolyte polymers is still lacking. In this study, dark-field microscopy and persistence length analysis help directly evaluate fiber mechanics using electrospun fibers of poly(acrylic acid) (PAA), chitosan (CS), and ferric ions as a model system. By comparing the persistence length and estimated Young’s modulus of different nanofibers, we demonstrate that persistence length analysis is a viable approach to evaluate mechanical properties of hydrated fibers. Ferric ions were found to create shorter and stiffer nanofibers, with Young’s modulus estimated at a few kilopascals. Ferric ions, at low concentration, reduce the Young’s modulus of PAA and PAA/CS fibers through the interaction between ferric ions and carboxylate groups. Such interaction was further supported by nanoscale infrared spectroscopy studies of PAA and PAA/CS fibers with different concentrations of ferric ions.
Superhydrophilic surfaces were used to achieve a uniform deposition of one-dimensional (1D) and two-dimensional (2D) nanomaterials for high performance transparent conductive films. Suspensions of silver nanowires (AgNWs, 1D) and graphene oxide (GO, 2D) were deposited on pristine glass substrates and superhydrophilic surfaces through various deposition methods. It was discovered that the coffee-ring effect, often observed during drop-casting, was suppressed by the rapid wetting of suspensions into a thin liquid sheet on superhydrophilic surfaces. Drop-casting of AgNW suspensions on superhydrophilic surfaces produced a uniform AgNW network that provided low sheet resistance (R s ) and high percent transmittance (%T) at 550 nm. The sample of a R s of 250 Ω sq −1 had a %T of 97.7, and the sample of a R s of 24.7 Ω sq −1 had a greater %T than pristine glass. Spray-coating of GO suspensions onto superhydrophilic films coated with AgNWs generated a conformal coating that reduced the areal root-mean-square roughness (Sq) from 28.4 nm down to 15.7 nm but showed limited improvement to the conductivity of the network. Conformal Au coating of the AgNW network stabilized the film against oxidation and granted mechanical stability through subsequent aqueous processing, such as spray-coating of GO films. The superhydrophilic substrates with antireflective properties were successful in generating high-performance TCFs and allowed for study of the dynamic processes of film formation from liquid dispersions of nanomaterials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.