Magnetic Nanoparticles in MR Imaging and Drug Delivery

Immobilization is often the key to optimizing the operational performance of an enzyme in industrial processes, particularly for use in non-aqueous media. Different methods for the immobilization of enzymes are critically reviewed. The methods are divided into three main categories, viz. (i) binding to a prefabricated support (carrier), (ii) entrapment in organic or inorganic polymer matrices, and (iii) cross-linking of enzyme molecules. Emphasis is placed on relatively recent developments, such as the use of novel supports, e.g., mesoporous silicas, hydrogels, and smart polymers, novel entrapment methods and cross-linked enzyme aggregates (CLEAs).

http://largens.com/biochemlab/peroxidase2.pdf

Enzyme immobilization: The quest for optimum performance

/pdf/degradable-controlled-release-polymers-and-polymeric-1y322ha58z.pdf

Degradable Controlled-Release Polymers and Polymeric Nanoparticles: Mechanisms of Controlling Drug Release

Biocompatibility, Pharmaceutical and Biomedical Applications L. Harivardhan Reddy,†,‡ Jose ́ L. Arias, Julien Nicolas,† and Patrick Couvreur*,† †Laboratoire de Physico-Chimie, Pharmacotechnie et Biopharmacie, Universite ́ Paris-Sud XI, UMR CNRS 8612, Faculte ́ de Pharmacie, IFR 141, 5 rue Jean-Baptiste Cleḿent, F-92296 Chat̂enay-Malabry, France Departamento de Farmacia y Tecnología Farmaceútica, Facultad de Farmacia, Campus Universitario de Cartuja s/n, Universidad de Granada, 18071 Granada, Spain ‡Pharmaceutical Sciences Department, Sanofi, 13 Quai Jules Guesdes, F-94403 Vitry-sur-Seine, France

Magnetic nanoparticles: design and characterization, toxicity and biocompatibility, pharmaceutical and biomedical applications.

Design and fabrication of magnetic nanoparticles for targeted drug delivery and imaging

The present Communication compares the thermosensitivity in dilute aqueous solutions of well-defined copolymers composed of 95% of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and 5% of oligo(ethylene glycol) methacrylate (OEGMA, Mn = 475 g·mol-1) and poly(N-isopropylacrylamide) (PNIPAM) samples having similar degrees of polymerization and chain-ends. The thermoresponsive behavior of P(MEO2MA-co-OEGMA) was found to be overall comparable, and in some cases, superior to PNIPAM. Hence, P(MEO2MA-co-OEGMA) copolymers can be considered as ideal structures, which combine both the properties of poly(ethylene glycol) and PNIPAM in a single macromolecule.

Point by point comparison of two thermosensitive polymers exhibiting a similar LCST: is the age of poly(NIPAM) over?

Preparation of Ideal PEG Analogues with a Tunable Thermosensitivity by Controlled Radical Copolymerization of 2-(2-Methoxyethoxy)ethyl Methacrylate and Oligo(ethylene glycol) Methacrylate

The phase transitions in water of well-defined copolymers of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA, Mn = 475 g mol-1) were studied by means of 1H NMR, dynamic light scattering (DLS) and turbidimetry. These copolymers were synthesized by atom transfer radical polymerization (ATRP) in order to obtain macromolecules with a homogeneous chain-to-chain comonomer composition and therefore with a narrow phase transition. As previously reported, copolymers containing 10 mol % of OEGMA per chain (Mn = 20 100 g mol-1 ; Mw/Mn = 1.35) exhibited a sharp LCST in water around 40 °C, whereas copolymers having 20 mol % of OEGMA per chain (Mn = 19 500 g mol-1; Mw/Mn = 1.32) precipitated slightly above 50 °C. DLS indicated that these phase transitions are most likely due to a reversible coil-to-globule transition. Moreover covalently cross-linked networks of MEO2MA and OEGMA were synthesized by ATRP in the presence of the cross-linker ethylene glycol dimethacrylate. The...

About the Phase Transitions in Aqueous Solutions of Thermoresponsive Copolymers and Hydrogels Based on 2-(2-methoxyethoxy)ethyl Methacrylate and Oligo(ethylene glycol) Methacrylate

One-pot synthesis of pegylated ultrasmall iron-oxide nanoparticles and their in vivo evaluation as magnetic resonance imaging contrast agents.

Co-polymers of 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methyl ether methacrylate (OEGMA300, M n = 300 g/mol) of various composition were synthesized at 60°C in ethanol solution either by conventional radical polymerization (RP) or atom transfer radical polymerization (ATRP). Both techniques led to co-polymers P(MEO2MA-co-OEGMA300) in high yields. However, ATRP provided better defined co-polymers with controlled molecular weight, composition and molecular weight distribution. Nevertheless, all the samples exhibited a lower critical solution temperature (LCST) in aqueous medium (i.e., pure deionized water or physiological buffer). Sharp and reversible phase transitions were observed in all cases by turbidimetry and dynamic light scattering. This thermoresponsive behavior was demonstrated to be directly linked to the MEO2MA/OEGMA300 composition of the formed co-polymers. Thus, the LCST of the co-polymers could be precisely adjusted in the temperature range 28–65°C.

https://www.tandfonline.com/doi/pdf/10.1163/156855509X448316

Ann Hoth

Papers

Point by point comparison of two thermosensitive polymers exhibiting a similar LCST: is the age of poly(NIPAM) over?

Preparation of Ideal PEG Analogues with a Tunable Thermosensitivity by Controlled Radical Copolymerization of 2-(2-Methoxyethoxy)ethyl Methacrylate and Oligo(ethylene glycol) Methacrylate

About the Phase Transitions in Aqueous Solutions of Thermoresponsive Copolymers and Hydrogels Based on 2-(2-methoxyethoxy)ethyl Methacrylate and Oligo(ethylene glycol) Methacrylate

One-pot synthesis of pegylated ultrasmall iron-oxide nanoparticles and their in vivo evaluation as magnetic resonance imaging contrast agents.

Design of Oligo(ethylene glycol)-Based Thermoresponsive Polymers: an Optimization Study