The efficacy of several cell therapy products is directly impacted by trypsinization, which can diminish the engrafting capacity of transplanted cells by cleaving cell surface receptors. Thermoresponsive surfaces can alleviate this drawback, enabling temperature-driven and enzyme-free cell harvesting. However, the production of thermoresponsive surfaces relies on dedicated and complex equipment, often involving protocols dependent on high surface activation energies that prevent the development of scalable and universal platforms. In this work, we developed thermoresponsive copolymers incorporating styrene units that enable the copolymer adsorption on tissue culture polystyrene surfaces from an alcoholic solution in a short time, regardless of the vessel size and geometry, and without any particular equipment. In this way, the procedure can be performed with minimal effort by the end user on any surface. The thermoresponsive copolymers were synthesized via reversible addition–fragmentation chain transfer polymerization, providing high control over the polymer microstructure, a key parameter for tuning its cloud point and architecture. Block copolymers comprising a thermoresponsive segment and a polystyrene block exhibited optimal adhesion on conventional cell culture surfaces and permitted a more efficient temperature-mediated harvesting of adipose-derived stromal cells and Chinese hamster ovary cells compared to their statistical counterparts. To expand the application of this polymer deposition protocol to serum-free cell culture, we also considered the polymer modification with the tripeptide arginine-glycine-aspartic acid, known to promote the cell adhesion to synthetic substrates. The incorporation of this peptide enabled the collection in serum-free conditions of intact cell sheets from surfaces prepared shortly before their usage.
Engineered polylactic acid (PLA) nanoparticles synthesized from oligo(lactic acid) macromonomers have been studied over the last decades for controlled drug delivery. These macromonomers are typically produced via ring‐opening polymerization (ROP) of the cyclic dimer lactide, initiated by 2‐hydroxyethyl methacrylate (HEMA). This reaction route, despite leading to well‐defined macromonomers, relies on the production of lactide from lactic acid, which burdens the ROP overall cost for more than 30%. In this work, we report the synthesis of PLA‐based macromonomers by direct polycondensation of lactic acid in the presence of HEMA as a valuable alternative to ROP. In particular, we compare the two processes side by side, focusing on the production of three HEMA‐LAn macromonomers, with n = 2, 4, and 6. Detailed kinetic models are developed for both reaction systems, and the corresponding parameters are estimated by fitting the experimental data. Through these models, the reaction kinetics as well as the time evolution of the entire chain length distributions of the products from polycondensation and ROP could be reliably predicted. This way, we demonstrated that polycondensation is a valuable alternative to ROP only for macromonomers with an average chain length of up to 4 and that ROP remains the main route to longer chains, when a strict control over the chain length distribution is required.
Over the last few years, oil companies have devoted much effort to decrease the amount of water that is pumped up with oil, especially from mature reservoirs, where the water production is huge. In addition to reducing the profit margin, the water extracted from an oil field is polluted by different organic and inorganic compounds and must be properly treated before being discharged or reinjected. Alternatively, it must be disposed of with high treatment and/or disposal costs. To overcome costs associated with water treatment/disposal, mechanical and chemical strategies aimed at reducing the amount of extracted water (i.e., water shut-off) are applied. Among them, hydrophilic polymeric micro-and nanogels are promising materials that are gaining increasing interest. They are three-dimensional networks able to retain water by increasing in size and thus creating a physical barrier to the water flowing. In this work, nano-and microabsorbent particles made up of crosslinked poly(methacrylic acid-co-oligo(ethylene glycol) methyl ether methacrylate) p(MAA-co-OEGMA) were synthesized via inverse suspension polymerization in Lamix, an aromatic-free hydrocarbon blend. The formulation was optimized in terms of OEGMA mole fraction to achieve a high swelling in seawater and hence high efficacy in the water shut-off. Finally, the suspension was modified to be produced on a ton scale and injected into an open-hole, partially depleted oil reservoir for a first pilot field test. One-year monitoring was conducted by evaluating the oil productivity as well as the water fraction (i.e., water cut) under conventional extraction procedures. This trial assessed a 30% decrease in the water cut, as well as an increase in the oil production from 5 to 30 m 3 /day. This confirmed the developed microgels as a promising tool for water shut-off.
Redispersible polymer powders (RDPPs), i.e., additives obtained from core-shell nanoparticles and commercialized in the form of a dry powder, find intensive application in the concrete industry. However, they are mainly produced from fossil resources. Therefore, the development of bio-based RDPPs is important to reduce the carbon footprint of these additives. In this work, two types of core-shell nanoparticles with a high percentage of bio-based content are synthesized and show to be good candidates as RDPPs. In the first case, up to 75% of bio-based content is obtained by combining lauryl acrylate, derived from coconut and palm kernel oil, as main core material, with isobornyl methacrylate, coming from pine resin, exploited to create the outer harder shell. In the second case, a degradable macromonomer obtained by the ring opening polymerization of lactide using 2-hydroxyethyl methacrylate as initiator is used as the core-forming monomer to obtain degradable RDPPs. In both cases, the particles are synthesized with a two-step emulsion polymerization process conducted in one pot and then spray-dried to obtain the RDPPs of interest. The morphology and redispersibility of the powders are characterized. Finally, their use as concrete additives is preliminarily assessed by evaluating their effect on changes in the surface morphologies of concrete specimens.
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.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2025 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.