Sub-100 nm carriers by template polymerization for drug delivery applications

Size-controlled drug delivery systems (DDSs) have gained significant attention in the field of pharmaceutical sciences due to their potential to enhance drug efficacy, minimize side effects, and improve patient compliance. This review provides a concise overview of the preparation method, advancements, and applications of size-controlled drug delivery systems focusing on the sub-100 nm size DDSs. The importance of tailoring the size for achieving therapeutic goals is briefly mentioned. We highlight the concept of "template polymerization", a well-established method in covalent polymerization that offers precise control over molecular weight. We demonstrate the utility of this approach in crafting a monolayer of a polymer around biomolecule templates such as DNA, RNA, and protein, achieving the generation of DDSs with sizes ranging from several tens of nanometers. A few representative examples of small-size DDSs that share a conceptual similarity to "template polymerization" are also discussed. This review concludes by briefly discussing the drug release behaviors and the future prospects of "template polymerization" for the development of innovative size-controlled drug delivery systems, which promise to optimize drug delivery precision, efficacy, and safety.

Self-Assembled Photonic Microsensors with Strong Aggregation-Induced Emission for Ultra-Trace Quantitative Detection

Ultratrace quantitative detection based on fluorescence is highly desirable for many important applications such as environmental monitoring or disease diagnosis, which however has remained a great challenge because of limited and irregular fluorescence responses to analytes at ultralow concentrations. Herein the problem is circumvented via local enrichment and detection of analytes within a microsensor, that is, photonic porous microspheres grafted with aggregation-induced emission gens (AIEgens). The obtained microspheres exhibit dual structural and molecular functions, namely, bright structural colors and strong fluorescence. Large fluorescence quenching induced by nitrophenol compounds in an aqueous environment is observed at ultralow concentrations (10^-12-10^-8 mol/L), enabling quantitative detection at a ppb level (ng/L). This is achieved within a porous structure with good connectivity between the nanopores to improve analyte diffusion, an internal layer of poly(ethylene oxide) (PEO) for analyte enrichment via hydrogen bonding, and homogeneous distribution of AIEgens within the PEO layer for enhanced fluorescence quenching. The fluorescent porous microspheres can be readily obtained in a single step templated by well-ordered water-in-oil-in-water double emulsion droplets with AIE amphiphilic bottlebrush block copolymers as the effective stabilizer.

Antioxidant Activity of Synthetic Polymers of Phenolic Compounds

In recent years, developing potent antioxidants has been a very active area of research. In this context, phenolic compounds have been evaluated for their antioxidant activity. However, the use of phenolic compounds has also been limited by poor antioxidant activity in several in vivo studies. Polymeric phenols have received much attention owing to their potent antioxidant properties and increased stability in aqueous systems. To be truly effective in biological applications, it is important that these polymers be synthesized using benign methods. In this context, enzyme catalyzed synthesis of polymeric phenols has been explored as an environmentally friendly and safer approach. This review summarizes work in enzymatic syntheses of polymers of phenols. Several assays have been developed to determine the antioxidant potency of these polymeric phenols. These assays are discussed in detail along with structure-property relationships. A deeper understanding of factors affecting antioxidant activity would provide an opportunity for the design of versatile, high performing polymers with enhanced antioxidant activity.

Carboxymethyl Cellulose (CMC) as a Template for Laccase-Assisted Oxidation of Aniline

Polyaniline (PANi) is a conducting polymer which has been subject of intensive research on the exploitation of new products and applications. The main aim of the work is the development of a conductive bacterial cellulose (BC)-based material by enzymatic-assisted polymerization of aniline. For this, we study the role of carboxymethyl cellulose (CMC) as a template for the in situ polymerization of aniline. Bacterial cellulose was used as the supporting material for the entrapment of CMC and for the in situ oxidation reactions. The amount of CMC entrapped inside BC was optimized as well as the conditions for laccase-assisted oxidation of aniline. The new oligomers were evaluated by spectrometric techniques, namely 1H NMR and MALDI-TOF, and the functionalized BC surfaces were analyzed by thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and reflectance spectrophotometry. The conductivity of the developed materials was evaluated using the four-probe methodology. The oligomers obtained after reaction in the presence of CMC as template display a similar structure as when the reaction is conducted only in BC. Though, after oxidation in the presence of this template, the amount of oligomers entrapped inside BC/CMC is considerably higher conferring to the material greater electrical conductivity and coloration. The use of CMC as a template for aniline oxidation on BC seems to be a promising and cheap strategy to improve the yield of functionalization and increment the properties of the materials, namely electrical conductivity and coloration.

Polymers from Bamboo Extracts Produced by Laccase

A green methodology for the production of polymers from bamboo powder was investigated. The optimal conditions for the extraction of components from bamboo were defined by incubating the powder in an acetate buffer (pH 5) under boiling for 2 h. Native laccase from Myceliophthora thermophila was used afterwards to oxidize the extracts from the final resulting extraction liquid. The reduction of the free OH content after enzymatic oxidation, as well as the ¹H NMR data, confirmed the efficient polymerization of the extracts. The bamboo powder samples were also subjected to high compression and curing, in the absence and in the presence of laccase, to evaluate the hardness of the tablets formed by enzymatic bonding events. The results revealed a higher hardness when the tablets were produced in the presence of laccase, confirming the role of the catalyst on the precipitation of colloidal lignin and phenolic extractives. Herein we produce new oligomers/polymers by laccase oxidation of the extracts resulting from a clean method boiling. At the same time, the data open up new routes for the exploitation of new lignocellulosic materials by the direct application of the enzyme on the bamboo powder material.

Laccase: a green catalyst for the biosynthesis of poly-phenols

Laccases (benzene diol: oxidoreductases, EC 1.10.3.2) are able to catalyze the oxidation of various compounds containing phenolic and aniline structures using dissolved oxygen in water. Laccase structural features and catalytic mechanisms focused on the polymerization of aromatic compounds are reported. A description about the most recent research on the biosynthesis of chemicals and polymers is made. Selected applications of this technology are considered as well as the advantages, shortcomings and future needs related with the use of laccases.

Removal of bisphenol A and its derivatives from aqueous medium through laccase-catalyzed treatment enhanced by addition of polyethylene glycol

In this study, enzymatic removal of bisphenol A (BPA) from the aqueous medium was investigated through the generation of water-insoluble oligomers, and this procedure was applied to removal of bisphenol derivatives. The experimental parameters, such as the temperature, pH value, enzyme concentration, and concentration and molecular weight of polyethylene glycol (PEG), were determined for the laccase-catalyzed treatment of BPA. The optimum conditions were determined to be pH 7.0 and 40°C in the absence of PEG. Water-insoluble oligomers generated under these conditions were readily removed by filtration or centrifugation. The optimum pH value was decreased to 5.0 in the presence of PEG and the laccase dose was reduced to one-fiftieth of that in the absence of PEG. This indicates that the addition of PEG protects the enzymatic activity and prevents capture of laccase molecules in the oligomers. The oligomers generated in the presence of PEG were removed from the aqueous medium by filtration with a membrane filter or by centrifugation. The oligomers were completely filtrated out with a filter paper by decreasing the pH value to 3.0. In addition, several bisphenol derivatives were also treated and subsequently removed by adjusting the laccase dose in the presence of PEG using the above procedure.