A Fluorescence Study on Surface Properties of Cationic Gemini Surfactant with Some Special Alcohols

Alcohols are very important additives and played a measure role as co-surfactants in various industrial and research applications. While, Gemini surfactants are mainly used as effective emulsifiers, antifoaming agents, bactericidal agents, coating agents and corrosion inhibitors etc. Therefore, it is important to study about the variations in alkanol concentrations which affects the aggregation number and other related parameters. Surface properties of gemini surfactant butanediyl-1,4-bis(dimethyldodecylammonium bromide) (12-4-12) has been studied by using fluorescence method. This method has been used to calculate the aggregation number (Nagg) and the other related parameters like dielectric constant (D), Stern Volmer binding constant (KSV) of mixed system. This method is also very important for the calculation of the micropolarity of the mixed system (gemini/alcohol). The micropolarity has been obtained with the help of the ratio of intensity of peaks (I1/I3) of the pyrene fluorescence emission spectrum. Cetylpridinium chloride and pyrene were used as quencher and probe, respectively. Keywords: Gemini surfactant, special alcohols, aggregation number, micropolarity

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

Mechanochemistry is an emerging and reliable alternative to conventional solution (batch) synthesis of complex molecules under green and solvent-free conditions. In this regard, we report here on the conjugation of a dextran polysaccharide with a fluorescent probe, a phenylboronic acid (PBA)-functionalized boron dipyrromethene (BODIPY) applying the ball milling approach. The ball milling formation of boron esters between PBA BODIPY and dextran proved to be more efficient in terms of reaction time, amount of reactants, and labelling degree compared to the corresponding solution-based synthetic route. PBA-BODIPY dextran assembles into nanoparticles of around 200 nm by hydrophobic interactions. The resulting PBA-BODIPY dextran nanoparticles retain an apolar interior as proved by pyrene fluorescence, suitable for the encapsulation of hydrophobic drugs with high biocompatibility while remaining fluorescent.

Synthesis of Amphiphilic Statistical Copolymers Bearing Methoxyethyl and Phosphorylcholine Groups and Their Self-Association Behavior in Water

Biocompatible amphiphilic statistical copolymers P(MEA/MPCm) composed of 2-methoxyethyl acrylate (MEA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) were prepared with three different mol% of the hydrophilic unit MPC (m = 6, 12 and 46 mol%). The monomer reactivity ratios of MEA (rMEA) and MPC (rMPC) were 0.53 and 2.21, respectively. The rMEA × rMPC value of 1.17 demonstrated that statistical copolymerization was successful. P(MEA/MPC12) and P(MEA/MPC46) copolymers did not undergo aggregation in water, whereas the P(MEA/MPC6) copolymer formed micelles in water with a hydrodynamic radius (Rh) of 96.9 nm and a critical aggregation concentration, which was determined using pyrene fluorescence, at 0.0082 g/L. The restricted motion of the protons in the hydrophobic MEA units in the micelles’ cores provided additional evidence of self-association in P(MEA/MPC6).

Physicochemical Properties of A New PEGylated Polybenzofulvene Brush for Drug Encapsulation

A new polymer brush was synthesized by spontaneous polymerization of benzofulvene macromonomer 6-MOEG-9-T-BF3k bearing a nona(ethylene glycol) side chain linked to the 3-phenylindene scaffold by means of a triazole heterocycle. The polymer structure was studied by SEC-MALS, NMR spectroscopy, and MALDI-TOF MS techniques, and the results supported the role of oligomeric initiatory species in the spontaneous polymerization of polybenzofulvene derivatives. The aggregation features of high molecular weight poly-6-MOEG-9-T-BF3k-FE were investigated by pyrene fluorescence analysis, dynamic light scattering studies, and transmission electron microscopy, which suggested a tendency towards the formation of spherical objects showing dimensions in the range of 20–200 nm. Moreover, poly-6-MOEG-9-T-BF3k-FE showed an interesting cytocompatibility in the whole concentration range tested that, besides its aggregation features, makes this polybenzofulvene brush a good polymer candidate for nanoencapsulation and delivery of drug molecules. Finally, the photo-physical features of poly-6-MOEG-9-T-BF3k-FE could allow the biodistribution of the resulting drug delivery systems to be monitored by fluorescence microscopy techniques.

Synthesis and biophysical characterization of oligonucleotides modified with O2′-alkylated RNA monomers featuring substituted pyrene moieties

Oligonucleotides modified with monomers V or Y display up to 22-fold increases in pyrene fluorescence emission upon binding with complementary RNA.