Preparation of biotinylated glyconanoparticles via a photochemical process and study of their bioconjugation to streptavidin

Photochemistry for Well-Defined Polymers in Aqueous Media: From Fundamentals to Polymer Nanoparticles to Bioconjugates

This review article highlights recent developments in the field of photochemistry and photochemical reversible deactivation radical polymerization applied to aqueous polymerizations. Photochemistry is a topic of significant interest in the fields of organic, polymer, and materials chemistry because it allows challenging reactions to be performed under mild conditions. Aqueous polymerization is of significant interest because water is an environmentally benign solvent, and the use of water enables complex polymer self-assembly and bioconjugation processes to occur. This review focuses on powerful new developments in photochemical aqueous polymerization reactions and their applications to the synthesis of well-defined polymer nano-objects and bioconjugates. It is anticipated that these aqueous photopolymerizations will enable the next generation of self-assembled structures and biohybrid materials to be developed under mild and environmentally friendly conditions.

Telechelic polymers from reversible-deactivation radical polymerization for biomedical applications

Strategies for the synthesis of telechelic polymers by reversible-activation radical polymerization for biomedical applications are covered spanning from drug delivery and targeting to theranostics and sensing.

Applications of Gold Nanoparticles in Biosensors

Gold nanoparticles (AuNPs) as one of the most stable metal nanoparticles have demonstrated extensive applications in recent years. This paper will give a focus on the AuNPs as biosensors, due to their inertness, unique optical properties, high surface area, and various surface functionalization methods. Synthesis of AuNps and the surface functionalization will be discussed in the first part. The size, shape, and stability can be controlled by different synthetic methods, while reductant usually needed. By surface functionalization with different molecules such as polymers, nucleic acids, and proteins, AuNPs will aggregate when specified molecule linkages showing up enables selective detections. The application in biosensing to detect proteins, oligonucleotide, glucose, and heavy metals will be exemplified, followed by the summary and future perspective part in the conclusion.

Fluorescent gold nanoparticles with chain-end grafted RAFT copolymers: influence of the polymer molecular weight and type of chromophore

Fluorescence of gold nanoparticles functionalized with chain-end grafted RAFT copolymers increases with polymer corona thickness.

Glyconanoparticles and their interactions with lectins

Glyconanoparticles and their interactions with lectins.

Glycopolymer code based on well-defined glycopolymers or glyconanomaterials and their biomolecular recognition

Advances in the glycopolymer technology have allowed the preparation of more complex and well-defined glycopolymers/particles with several architectures from linear to globular structures (such as micelles, dendrimers, and nanogels). In the last decade, functionalized self-assembled/decided nano-objects and scaffolds containing glycopolymers were designed to develop many biological and biomedical applications in diseases treatments such as pathogen detection, inhibitors of toxins, and lectin-based biosensors. These studies will facilitate the understanding and investigation of the sugar code on the carbohydrate-lectin interactions, which are significantly influenced by the glycopolymer architecture, valency, size, and density of binding elements. In this context, these advanced and selected glycopolymers/particles showing specific interactions with various lectins are highlighted.

Selectivity among two lectins: probing the effect of topology, multivalency and flexibility of "clicked" multivalent glycoclusters

The design of multivalent glycoconjugates has been developed over the past decades to obtain high-affinity ligands for lectin receptors. While multivalency frequently increases the affinity of a ligand for its lectin through the so-called "glycoside cluster effect", the binding profiles towards different lectins have been much less investigated. We have designed a series of multivalent galactosylated glycoconjugates and studied their binding properties towards two lectins, from plant and bacterial origins, to determine their potential selectivity. The synthesis was achieved through copper(I)-catalysed azide-alkyne cycloaddition (CuAAC) under microwave activation between propargylated multivalent scaffolds and an azido-functionalised carbohydrate derivative. The interactions of two galactose-binding lectins from Pseudomonas aeruginosa (PA-IL) and Erythrina cristagalli (ECA) with the synthesized glycoclusters were studied by hemagglutination inhibition assays (HIA), surface plasmon resonance (SPR) and isothermal titration microcalorimetry (ITC). The results obtained illustrate the influence of the scaffold's geometry on the affinity towards the lectin and also on the relative potency in comparison with a monovalent galactoside reference probe.

Impact of pre-concentration to covalently biofunctionalize suspended nanoparticles

The effective biofunctionalization of nanoparticles is crucial for biomedical applications. In this study we investigated the covalent biofunctionalization of magnetic nanoparticles based on carbodiimide activation. An important aspect in the covalent biofunctionalization of nanoparticles has been neglected, namely pre-concentration. Exploiting the electrostatic attraction forces between a protein and the nanoparticle surface will favor the covalent immobilization. We showed that low ionic strength buffers with a pH slightly lower than the pI of the selected biomolecules is needed to increase the yield of covalent immobilization. Additionally, it is demonstrated that the covalently immobilized proteins are bioactive, relying on a sandwich assay using gold nanoparticles as reporter labels.

Nanoparticle-based vaginal drug delivery systems for HIV prevention

IMPORTANCE OF THE FIELD

Several strategies are being investigated for the prevention of heterosexual transmission of HIV. Of these, topical vaginal drug delivery systems, microbicides, are being actively pursued. HIV prevention by means of a topical microbicide has several drug delivery challenges. These challenges include the vaginal mucosal barriers and potential degradation of the drugs in the vaginal lumen due to pH and enzymes present. Also, new drugs being evaluated as microbicides have specific mechanisms of action, which in some cases require drug targeting to a specific site of action. Nanoparticles provide a delivery strategy for targeted or controlled delivery to the vagina which can be applied in the field of HIV prevention.

AREAS COVERED IN THE REVIEW

This review summarizes nanoparticulate systems and their use in mucosal delivery to date. The sexual transmission of HIV along with the various targets to prevent transmission are discussed as well as the potential opportunities, challenges and advantages in using a nanoparticle-based approach for microbicidal drug delivery.

WHAT THE READER WILL GAIN

This review provides a general understanding of vaginal drug delivery, its challenges, and nanoparticulate delivery systems. Additionally, insight will be gained as to the limited existing application of this technology to the field of HIV prevention.

TAKE HOME MESSAGE

To date, few studies have been published that exploit nanoparticle-based microbicidal delivery to the vagina. The use of nanoparticles for vaginal drug delivery provides an approach to overcome the existing barriers to success.

Synthesis of a pyridyl disulfide end-functionalized glycopolymer for conjugation to biomolecules and patterning on gold surfaces

A pyridyl disulfide end-functionalized polymer with N-acetyl-d-glucosamine pendant side-chains was synthesized by atom transfer radical polymerization (ATRP). The glycopolymer was prepared from a pyridyl disulfide initiator catalyzed by a Cu(I)/Cu(II)/2,2'-bipyridine system in a mixture of methanol and water at 30 degrees C. The final polymer had a number-average molecular weight (M(n)) of 13.0 kDa determined by (1)H NMR spectroscopy and a narrow polydispersity index (1.12) determined by gel permeation chromatography (GPC). The pyridyl disulfide end-group was then utilized to conjugate the glycopolymer to a double-stranded short interfering RNA (siRNA). Characterization of the glycopolymer-siRNA by polyacrylamide gel electrophoresis (PAGE) showed 97% conjugation. The activated disulfide polymer was also patterned on gold via microcontact printing. The pyridyl disulfide allowed for ready immobilization of the glycopolymer into 200 microm sized features on the surface.

Study of transfection efficiencies of cationic glyconanoparticles of different sizes in human cell line

The growing attention toward the synthesis and uses of gold nanoparticles for biomedical applications is based on their biocompatibility, ease of functionalization, and unique optical and electronic properties. Recently, the gold nanoparticles are also found to induce the size-dependent interactions with living tissues. It has been found that gold nanoparticles of different sizes are uptaken by the cells in vitro and by the organs of living specimens in vivo at different rates. Herein, we report the use of gold nanoparticles of different sizes as a gene delivery agent. The gold nanoparticles of 10, 40, and 100 nm diameter were surface functionalized with cationic glycopolymer, and their biocompatibility under physiological conditions was investigated. The stable nanoparticles were then complexed with enhanced cyanine fluorescence protein plasmid (pECFP) and their transfection efficiencies in Hela cell line were studied. It was found that gold nanoparticles of 40 nm core diameter exhibit highest transfection efficiencies compared to the other sizes of nanoparticles studied.