Determining the Q-e values of polymer radicals and monomers separately through the derivation of an intrinsic Q-e scheme for radical copolymerization

Herein, we describe the first non-arbitrary determination of the Q-e values for individual polymer radicals and monomers. For this purpose, two reference monomers were subjected to a Q-e scheme, which...

Thiol-Functional Polymer Nanoparticles via Aerosol Photopolymerization

Spherical, individual polymer nanoparticles with functional –SH groups were synthesized via aerosol photopolymerization (APP) employing radically initiated thiol-ene chemistry. A series of various thiol and alkene monomer combinations were investigated based on di-, tri-, and tetrafunctional thiols with difunctional allyl and vinyl ethers, and di- and trifunctional acrylates. Only thiol and alkene monomer combinations able to build cross-linked poly(thio-ether) networks were compatible with APP, which requires fast polymerization of the generated droplet aerosol during the photoreactor passage within a residence time of half-minute. Higher monomer functionalities and equal overall stoichiometry of functional groups resulted in the best nanoparticles being spherical and individual, proven by scanning electron microscopy (SEM). The presence of reactive—SH groups in the synthesized nanoparticles as a basis for post-polymerization modifications was verified by Ellman’s test.

Advances in the Multi-Orthogonal Folding of Single Polymer Chains into Single-Chain Nanoparticles

The folding of certain proteins (e.g., enzymes) into perfectly defined 3D conformations via multi-orthogonal interactions is critical to their function. Concerning synthetic polymers chains, the “folding” of individual polymer chains at high dilution via intra-chain interactions leads to so-called single-chain nanoparticles (SCNPs). This review article describes the advances carried out in recent years in the folding of single polymer chains into discrete SCNPs via multi-orthogonal interactions using different reactive chemical species where intra-chain bonding only occurs between groups of the same species. First, we summarize results from computer simulations of multi-orthogonally folded SCNPs. Next, we comprehensively review multi-orthogonally folded SCNPs synthesized via either non-covalent bonds or covalent interactions. Finally, we conclude by summarizing recent research about multi-orthogonally folded SCNPs prepared through both reversible (dynamic) and permanent bonds.

Advances in the Multi-Orthogonal Folding of Single Polymer Chains into Single-Chain Nanoparticles

The folding of certain proteins (e.g., enzymes) into perfectly defined 3D conformations via multi-orthogonal interactions is critical to their function. Concerning synthetic polymers chains, the “folding” of individual polymer chains at high dilution via intra-chain interactions leads to so-called single-chain nanoparticles (SCNPs). This review article describes the advances carried out in recent years in the folding of single polymer chains into discrete SCNPs via multi-orthogonal interactions using different reactive chemical species where intra-chain bonding only occurs between groups of the same species. First, we summarize results from computer simulations of multi-orthogonally folded SCNPs. Next, we comprehensively review multi-orthogonally folded SCNPs synthesized via either non-covalent bonds or covalent interactions. Finally, we conclude by summarizing recent research about multi-orthogonally folded SCNPs prepared through both reversible (dynamic) and permanent bonds.

Improved Efficacy of Lovastatin from Soluplus-PEG Hybrid Polymer- Based Binary Dispersions

Background: Lovastatin is a statin drug used for lowering cholesterol in those with hypercholesterolemia to reduce the risk of cardiovascular disease. It is a BCS class II drug i.e. it has low aqueous solubility and high permeability. Objective: Improvement of solubility and in vivo efficacy was investigated by formulating binary solid dispersions. Methods: Binary solid dispersions of lovastatin were formulated in the current study using two polymers i.e. Soluplus and PEG 4000. Seven batches of solid dispersions were prepared (S1, P1, SP1, SP2, SP3, SP4, and SP5) via the solvent evaporation method. The prepared dispersions were evaluated for equilibrium solubility, FTIR, XRD, DSC, SEM studies, and further in vitro drug release were evaluated. The results revealed significant enhancement in the solubility of drug-using polymer hybrids as compared to that of individual polymer dispersion batches. Results: A significant solubility enhancement was observed with SP5 (approx 40 times) having a higher concentration of Soluplus. FTIR studies indicated no drug to polymer interaction. DSC studies revealed complete amorphization of polymer and also X-RD data is also in compliance with DSC results. In vitro drug release studies showed almost 100% release in 2h in polymer hybrid batches in comparison to individual polymer batch (S1 and P1). The best dissolution characteristics were observed in SP3 and SP5 which is also in compliance with solubility data. Further in vivo efficacy studies revealed a significant reduction in LDL, HDL, TG, AST, and ALT levels in comparison to pure drug lovastatin group and hypercholesterolemia control group. Conclusion: Hybrid polymer may be a prospective carrier system for the enhancement of solubility of BCS class II drugs.

Oxidative regulation of the mechanical strength of a C–S bond

The mechanical strength of individual polymer chains is believed to underlie a number of performance metrics in bulk materials, including adhesion and fracture toughness.

The optical signatures of molecular-doping induced polarons in poly(3-hexylthiophene-2,5-diyl): individual polymer chains versus aggregates

For molecularly doped poly(3-hexyl-thiophene) solvated individual chains can be unambiguously differentiated from aggregated ones by diagnostic polaron absorption.

CHEMICAL MODIFICATIONS OF ALGINATE AND ITS DERIVATIVES

Alginate is a polysaccharide obtained from seaweeds that are abundantly available and have shown great potential for diverse industrial applications. However, alginate lacks properties such as stability under aqueous conditions and it is difficult to control the rate of degradation of alginate-based materials, crucial for various medical applications. Therefore, researchers have modified alginate using physical or chemical approaches to enhance physical properties, biocompatibility, solubility and also to control the biodegradability of alginate-based materials. Crosslinking using ionic, covalent, photo and enzymatic approaches are one of the preferred methods for modifying the properties of alginates and its derivatives. Crosslinking binds the individual polymer chains with one another to form a network that enhances mechanical properties and stability. Among the different crosslinking approaches, ionic crosslinking provides biomaterials with limited stability whereas biomaterials with high mechanical stability can be prepared by covalent crosslinking. Although a wide variety of crosslinking chemicals and approaches are available to make alginate suitable for various applications, the methods used, properties and applications of the cross-linked materials vary significantly between studies. There are very few reports that have compared and evaluated the benefits of using different crosslinking approaches and the properties and applications of cross-linked alginate. In this review, the various methods of crosslinking alginates, their advantages, and limitations have been reviewed with particular emphasis on medical applications of alginate. The data for writing the review was obtained using search engines like Google scholar, Sci-hub and Sci finder and the keywords used include alginate, crosslinking, ionic, covalent, photo, enzymatic, biomedical applications.