Search results for "polymers"
showing 10 items of 3567 documents
PEG-benzofulvene copolymer hydrogels for antibody delivery.
2010
A new amphiphilic copolymer have been synthesized starting from the hydrosoluble polyaspartylhydrazide (PAHy) polymer, by grafting both hydrophilic PEG(2000) chains and hydrophobic palmitic acid (C(16)) moieties on polymer backbone, and the structure of obtained PAHy-PEG(2000)-C(16) copolymer have been characterized by 2D (1)H/(13)C NMR experiments. PAHy-PEG(2000)-C(16) copolymer showed the ability of self-assembling in aqueous media giving a core-shell structure and resulted potentially useful for encapsulating and dissolving hydrophobic drug. The formation of micellar core-shell structure has been investigated by 2D (1)H NMR NOESY experiments. The presence of cross-peaks for protons of C(…
Hybrid assemblies based on a gadolinium-containing polyoxometalate and a cationic polymer with spermine side chains for enhanced MRI contrast agents.
2013
Supramolecular assembly: Spherical and stable hybrid assemblies based on a cationic polymer with spermine side chains and an anionic Gd(3+)-containing polyoxometalate cluster (GdW) are prepared by electrostatic interaction. The T1-weighted MRI performance of GdW is enhanced about three times in the assemblies; meanwhile, the assemblies show good biocompatibility, which enables them to be promising candidates for MRI contrast agents.
Recent advances on thermosensitive and pH-sensitive liposomes employed in controlled release
2019
Nanotechnology has recently gained lots of interest in drug delivery due to its potential to improve the therapeutic outcomes of various diseases. Particularly, a wide range of different nano-sized vesicles has been investigated for drug delivery. Among them, one of the most attractive and well-investigated nanocarriers are liposomes. Although liposomes have several advantages such as low toxicity, biodegradability and biocompatibility as well as accumulate in tumor site via enhanced permeability and retention (EPR) effect, inefficient drug delivery to the target cells could affect the therapeutic purpose of most of conventional liposomal formulations. Therefore, new systems of drug release…
New gellan gum-graft-poly(D,L-lactide-co-glycolide) copolymers as promising bioinks: Synthesis and characterization
2020
This research focused on the aim of tackling the urgent demand of printable biomaterials, hence we synthetized and characterized three gellan gum-graft-poly(d,l-lactide-co-glycolide) copolymers (GGm-PLGA a, b and c) which differed in the graft substitution degree. We investigated the effect of the polyester chain grafted onto hydrophilic backbone of gellan gum in terms of physicochemical properties and the ability of the system to print 3D cell laden constructs. In particular, we evaluated thermo-rheological, ionotropic crosslinking, shear thinning, swelling and stability properties of these copolymers and their derived biomaterials and findings related to the degree of functionalization. M…
Effect of biobased plasticizers, used as dispersing aids, on mechanical, rheological and thermal properties of micro fibrillated cellulose (MFC)/poly…
2022
Micro Fibrillated Cellulose (MFC) has gained interest both in academia and industry, but some critical issues must be overcome to exploit the industrial MFC/biocomposites uses. In particular, the first drawback is related to the MFC agglomeration during the primary processing. Encouraging results have been obtained using plasticizers, as dispersing aids, during the extrusion that optimizes the process parameters based on the variation of the melt viscosity. However, even if the plasticizer addition counterbalances the excessive biocomposite stiffness, caused by the addition of the MFC, its eventual migration from the finished product needs to be evaluated to avoid toughness reductions as we…
Silver Oxide Mediated Monotosylation of Poly(ethylene glycol) (PEG): Heterobifunctional PEG via Polymer Desymmetrization
2017
Heterobifunctional poly(ethylene glycol)s (PEGs) are key structures for bioconjugation in the context of the “PEGylation” strategy to enhance blood circulation times of, for example, peptide drugs or “stealth” liposomes. The formation of heterobifunctional PEGs from symmetric PEG diols is challenging because of limited yields of the targeted monofunctional product and difficulties associated with separation steps. On the basis of a detailed comparison of reaction conditions, we have investigated a “polymer desymmetrization” strategy to maximize the yields of monofunctional PEG tosylate. The tosylation reaction in the presence of the heterogeneous catalyst silver oxide and potassium iodide i…
Thermal transformation of micro-crystalline cellulose in phosphoric acid
2011
Use of crude oil derivatives such as diesel and gasoline is becoming unsuitable due to their detriment to environment and to the increasing worldwide energy demand which is driving crude oil reservoirs towards exhaustion. Replacement of diesel and gasoline with biofuels (i.e. biodiesel and bioethanol, respectively) is very desirable. In fact, biofuels are not only environmentally sustainable, but also potentially inexhaustible due to the large amounts of waste biomasses from which they can be retrieved. In the present study, a model compound (micro-crystalline cellulose) was dissolved in phosphoric acid and converted at 80 °C to glucose, thereby providing the possible substrate for fermenta…
Effect of actively targeted copolymer coating on solid tumors eradication by gold nanorods-induced hyperthermia.
2020
Efforts in the field of anticancer therapy are increasingly focusing on the development of localized and selective treatments. Photothermal therapy (PTT) can lead to a spatially confined death of cancer cells, exploiting an increasing in temperature generated after UV-NIR irradiation of peculiar materials. Herein, a new actively targeted gold-based drug delivery system, named PHEA-LA-Fol-AuNRs/Iri, was explored for hyperthermia and chemotherapy colon cancer treatment. Gold nanorods were stabilized using a folate-derivative of α,β-poly(N-2-hydroxyethyl)-D,L-aspartamide (PHEA-LA-PEG-FA) as coating agent and then loaded with the antineoplastic drug irinotecan (Iri). The efficacy of empty and i…
Efficient Shielding of Polyplexes Using Heterotelechelic Polysarcosines
2018
Shielding agents are commonly used to shield polyelectrolyte complexes, e.g. polyplexes, from agglomeration, precipitation in complex media, like blood, and thus enhance their circulation times in vivo. Since up to now primarily poly(ethylene glycol) (PEG) has been investigated to shield non-viral carriers for systemic delivery, we report on the use of polysarcosine (pSar) as a potential alternative for steric stabilization. A redox-sensitive, cationizable lipo-oligomer structure (containing two cholanic acids attached via a bioreducible disulfide linker to an oligoaminoamide backbone in T-shape configuration) was equipped with azide-functionality by solid phase supported synthesis. After m…
Modifying the body distribution of HPMA-based copolymers by molecular weight and aggregate formation.
2011
There is a recognized need to create well-defined polymer probes for in vivo and clinical positron emission tomography (PET) imaging to guide the development of new generation polymer therapeutics. Using the RAFT polymerization technique in combination with the reactive ester approach, here we have synthesized well-defined and narrowly distributed N-(2-hydroxypropyl)methacrylamide homopolymers (pHPMA) (P1* and P2*) and random HPMA copolymers consisting of hydrophilic HPMA and hydrophobic lauryl methacrylate comonomers (P3* and P4*). The polymers had molecular weights below (P1* and P3*) and above the renal threshold (P2* and P4*). Whereas the homopolymers dissolve in isotonic solution as in…