Alginate: properties and biomedical applications

Hydrogel: Preparation, characterization, and applications: A review

https://www.farm.ucl.ac.be/Full-texts-FARM/Danhier-2010-2.pdf

To exploit the tumor microenvironment: Passive and active tumor targeting of nanocarriers for anti-cancer drug delivery

In medicine, nanotechnology has sparked a rapidly growing interest as it promises to solve a number of issues associated with conventional therapeutic agents, including their poor water solubility (at least, for most anticancer drugs), lack of targeting capability, nonspecific distribution, systemic toxicity, and low therapeutic index. Over the past several decades, remarkable progress has been made in the development and application of engineered nanoparticles to treat cancer more effectively. For example, therapeutic agents have been integrated with nanoparticles engineered with optimal sizes, shapes, and surface properties to increase their solubility, prolong their circulation half-life, improve their biodistribution, and reduce their immunogenicity. Nanoparticles and their payloads have also been favorably delivered into tumors by taking advantage of the pathophysiological conditions, such as the enhanced permeability and retention effect, and the spatial variations in the pH value. Additionally, targeting ligands (e.g., small organic molecules, peptides, antibodies, and nucleic acids) have been added to the surface of nanoparticles to specifically target cancerous cells through selective binding to the receptors overexpressed on their surface. Furthermore, it has been demonstrated that multiple types of therapeutic drugs and/or diagnostic agents (e.g., contrast agents) could be delivered through the same carrier to enable combination therapy with a potential to overcome multidrug resistance, and real-time readout on the treatment efficacy. It is anticipated that precisely engineered nanoparticles will emerge as the next-generation platform for cancer therapy and many other biomedical applications.

Engineered Nanoparticles for Drug Delivery in Cancer Therapy

Future perspectives and recent advances in stimuli-responsive materials

A detailed study of the pH- and sugar-responsive behavior of poly(3-acrylamidophenylboronic acid pinacol ester)-b-poly(N,N-dimethylacrylamide) (PAPBAE-b-PDMA) block copolymers is presented. Reversible addition-fragmentation chain transfer (RAFT) polymerization of the pinacol ester of 3- acrylamidophenylboronic acid resulted in homopolymers with molecular weights between 12,000 and 37,000 g/mol. The resulting homopolymers were employed as macro-chain trans- fer agents during the polymerization of N,N-dimethylacryla- mide (DMA). Successful chain extension and removal of the pinacol protecting groups to yield poly(3-acrylamidophenylbor- onic acid)-b-PDMA (PAPBA-b-PDMA) with free boronic acid moieties resulted in pH- and sugar-responsive block copoly- mers that were subsequently investigated for their behavior in aqueous solution. The PAPBA-b-PDMA block copolymers were capable of solution self-assembly due to the PAPBA block being water-insoluble below its pKa. The resulting aggregates were demonstrated to solubilize and release model hydropho- bic compounds, as demonstrated by fluorescence studies. Dis- sociation of the aggregates was induced by raising the pH above the pKa of the boronic acid residues or by adding sugars capable of forming boronate esters. Aggregate size, dissocia- tion kinetics, and the effect of various sugars were considered. The critical sugar concentration needed to induce aggregate dissociation was tuned by incorporation of hydrophilic DMA units within the PAPBA responsive segment to yield PDMA-b- poly(3-acrylamidophenylboronic acid-co-DMA) block copoly- mers. V C 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 50: 3373-3382, 2012

Tuning the Sugar-Response of Boronic Acid Block Copolymers

Polymeric nanoaggregate drug-delivery compositions including boron-containing copolymers are described. The drug-delivery compositions may further include a therapeutic agent comprising a nucleic acid, a polynucletide, a peptide, a polypeptide, a protein, a pharmaceutical or any combinations thereof. Methods for making the polymeric nanoaggregate compositions including at least one therapeutic agent (for example, insulin) as well as methods for administration of these compositions to mammals are also set forth. The disclosure also describes compositions and methods for controlled drug delivery. Further, polymeric nanoaggregate boron-containing compositions including insulin and methods for monitoring and regulating blood glucose levels of a mammal are also described. The disclosure also describes methods for treatment and/or control of diabetes mellitus by administering polymeric nanoaggregate boron-containing compositions including insulin to a mammal in need.

Boronic acid-containing block copolymers for controlled drug delivery

Biological‐ and Field‐Responsive Polymers: Expanding Potential in Smart Materials

Atom transfer radical polymerization (ATRP) was used to graft poly(methyl methacrylate), PMMA, onto poly(methylphenylphosphazene), [(Me)(Ph)PN]
 n
 , PMPP. A two-step process was used to convert a portion of the methyl substituents on [(Me)(Ph)PN]
 n
 to –CH2C(CH3)2OH groups and then to bromoalkyl groups, –CH2C(CH3)2OC(=O)C(CH3)2Br, the latter of which served as initiation sites for ATRP of methyl methacrylate (MMA) in the presence of CuCl/bipyridine. Variations in the length of the grafted chains were investigated and the graft copolymers were compared to the parent polymer and blends of similar composition. The new bromoalkyl derivatives of [(Me)(Ph)PN]
 n
 and the PMPP–graft–PMMA copolymers were characterized by elemental analysis, 1H and 31P NMR spectroscopy, size exclusion chromatography (SEC), and differential scanning calorimetry (DSC).

Jennifer N. Cambre

Papers

Tuning the Sugar-Response of Boronic Acid Block Copolymers

Boronic acid-containing block copolymers for controlled drug delivery

Biological‐ and Field‐Responsive Polymers: Expanding Potential in Smart Materials

Poly(methylphenylphosphazene)–Graft–Poly(methyl Methacrylate) Copolymers Via Atom Transfer Radical Polymerization