Preparation of Gold Nanoparticle–DNA Conjugates

This unit describes the preparation of conjugates between nanometer‐scale gold particles and synthetic oligonucleotides. Oligonucleotide‐functionalized gold nanoparticles are finding increased use in both the construction of complex, tailored nanostructures and the optimization of DNA sequence analysis. The protocols in this unit outline the synthesis, purification, and characterization of nanoparticle‐DNA conjugates for applications in nanotechnology and biotechnology. Separate procedures are presented for nanoparticles functionalized with just one or a few oligonucleotide strands and for nanoparticles functionalized with a dense layer of oligonucleotide strands. The different physical and chemical properties of these two types of conjugates are discussed, as are their stability and utility in different environments.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/143655/1/cpnc1202.pd

Functional nanostructures by NiCCo-PISA of helical poly(aryl isocyanide) copolymers

Herein, we present a straightforward and versatile methodology to achieve functional polymeric nano-objects that contain helical cores. Nickel-catalysed coordination polymerisation-induced self-assembly (NiCCo-PISA) of helical poly(aryl isocyanide) amphiphilic diblock copolymers was..

Isoselective Ring-Opening Polymerization of rac-Lactide From Chiral Takemoto’s Organocatalysts:Elucidation of Stereocontrol

Despite significant advances in organocatalysis, stereoselective polymerization reactions utilizing chiral organocatalysts have received very little attention, and much about the underlying mechanisms remains unknown. Here, we report that both commercially available (R,R)- and (S,S)-enantiomers of chiral thiourea-amine Takemoto’s organocatalysts promote efficient control and high isoselectivity at room temperature of the ring-opening polymerization (ROP) of racemic lactide by kinetic resolution, yielding highly isotactic, semicrystalline and metal-free polylactide (PLA). Kinetic investigations and combined analyses of the resulting PLAs have allowed the stereocontrol mechanism, which eventually involves both enantiomorphic site control and chain-end control, to be determined. Moreover, epimerization of rac-LA to meso-LA is identified as being responsible for the introduction of some stereoerrors during the ROP process

Stereoselective ROP of rac- and meso-lactides using achiral TBD as catalyst

1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD) polymerizes rac-lactide (rac-LA) to form highly isotactic polylactide (PLA) with a Pm = 0.88, while meso-LA yields heterotactic PLA (Pm ~ 0.8) at −75 °C. The stereocontrol of the cryogenic-based ring-opening polymerization comes from a perfect imbrication of both chiral LA and the propagating chiral end-group interacting with the achiral TBD catalyst

Consensus on circulatory shock and hemodynamic monitoring. Task force of the European Society of Intensive Care Medicine.

OBJECTIVE: Circulatory shock is a life-threatening syndrome resulting in multiorgan failure and a high mortality rate. The aim of this consensus is to provide support to the bedside clinician regarding the diagnosis, management and monitoring of shock. METHODS: The European Society of Intensive Care Medicine invited 12 experts to form a Task Force to update a previous consensus (Antonelli et al.: Intensive Care Med 33:575-590, 2007). The same five questions addressed in the earlier consensus were used as the outline for the literature search and review, with the aim of the Task Force to produce statements based on the available literature and evidence. These questions were: (1) What are the epidemiologic and pathophysiologic features of shock in the intensive care unit ? (2) Should we monitor preload and fluid responsiveness in shock ? (3) How and when should we monitor stroke volume or cardiac output in shock ? (4) What markers of the regional and microcirculation can be monitored, and how can cellular function be assessed in shock ? (5) What is the evidence for using hemodynamic monitoring to direct therapy in shock ? Four types of statements were used: definition, recommendation, best practice and statement of fact. RESULTS: Forty-four statements were made. The main new statements include: (1) statements on individualizing blood pressure targets; (2) statements on the assessment and prediction of fluid responsiveness; (3) statements on the use of echocardiography and hemodynamic monitoring. CONCLUSIONS: This consensus provides 44 statements that can be used at the bedside to diagnose, treat and monitor patients with shock

Multicomponent nanoparticles via self-assembly with cross-linked block copolymer surfactants

We describe a simple and versatile protocol to prepare water-soluble multifunctional nanostructures by encapsulation of different nanoparticles in shell cross-linked, block copolymer micelles. This method permits simultaneous incorporation of different nanoparticle properties within a nanoscale micellar container. We have demonstrated the co-encapsulation of magnetic (??-Fe2O3 and Fe3O4), semiconductor (CdSe/ZnS), and metal (Au) nanoparticles in different combinations to form multicomponent micelles that retain the precursor particles' distinct properties. Because these multifunctional hybrid nanostructures spontaneously assemble from solution by simultaneous desolvation of nanoparticles and amphiphilic block copolymer components, we anticipate that this can be used as a general protocol for preparing multifunctional nanostructures without explicit multimaterial synthesis or surface functionalization of nanoparticles.close878

Carbon nanotube-protein carriers enhance size-dependent self-adjuvant antibody response to haptens

Carbon nanotubes (CNTs) are nanomaterials with interesting emerging applications. Their properties make CNTs excellent candidates for use as new nanovehicles in drug delivery, immunization and diagnostics. In the current study, we assessed the immune-response-amplifying properties of CNTs to haptens by using azoxystrobin, the first developed strobilurin fungicide, asamodel analyte. Anazoxystrobin derivative bearingacarboxylated spacer arm (hapten AZc6) was covalently coupled to bovine serum albumin (BSA), and the resulting BSA-AZc6 conjugate was covalently linked to four functionalized CNTs of different shapes and sizes, varying in diameter and length. These four types of CNT-based constructs were obtained using efficient, fast, and easy functionalization procedures based on microwave-assisted chemistry. New Zealand rabbits and BALB/c mice were immunized with BSA-AZc6 alone and with the four CNT-BSA-AZc6 constructs, both with and without Freund's adjuvant. The IgG-type antibody responses were assessed in terms of the titer and affinity, paying special attention to the relationship between the immune response and the size and shape of the employed CNTs. Immunization with CNT-BSA-AZc6 resulted in enhanced titers and excellent affinities for azoxystrobin. More important, remarkable IgG responses were obtained even in the absence of an adjuvant, thus proving the self-adjuvanting capability of CNTs. Immunogens were able to produce strong anti-azoxystrobin immune responses in rabbits even when administered at a BSA-AZc6 conjugate dose as low as 0.05 μg. The short and thick CNT-BSA-AZc6 construct produced the best antibody response under all tested conditions. © 2013 Elsevier B.V. All rights reserved.This work was supported by the Ministerio de Educación y Ciencia (AGL2009-12940-C02-01/02/ALI) and cofinanced by the FEDER funds. J.P. was hired by Consejo Superior de Investigaciones Científicas (CSIC) under a predoctoral I3P contract. J.V.M. was also hired by CSIC with a postdoctoral contract under the Ramón y Cajal Program. All contracts were cofinanced by the Ministerio de Ciencia e Innovación and the European Social Fund. TEM images were obtained in the SCSIE Microscopy Service of the University of Valencia.Peer Reviewe

Self-catalysed folding of single chain nanoparticles (SCNPs) by NHC-mediated intramolecular benzoin condensation

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