A novel Fourier transform infrared (FT-IR) microscopy method was developed and used to analyze the diffusion of lipase CalB in two different resins during immobilization. The method consisted of a streamlined sample preparation process and an automated transmission FT-IR microscopic measurement using a commercial benchtop device. The immobilization of CalB was performed on a hydrophobic resin containing aromatic groups (ECR1030M based on divinylbenzene) and on a hydrophilic resin containing ester groups and thus oxygen (ECR8204M based on methacrylate) and FT-IR revealed that the kinetic of immobilization and the distribution of the enzyme on the two resins were completely different. Furthermore, the technique revealed that CalB was immobilized on the external surface only in the case of the hydrophobic ECR1030M in a layer of about 50–70 µm, whereas when immobilized on the hydrophilic carrier ECR8204M the interaction of the enzyme with the carrier was uniform over the full diameter of the polymer bead. The enzyme activity however was higher on the hydrophobic support ECR1030M.

A host–guest-based fluorescent composite with a large Stokes shift was synthesized by intercalating 2,2′-(thiophene-2,5-diyl)bis(benzo[d]oxazol-6-amine) (BBTA) into the nanochannels of zeolite L (ZL) and sealing the pores with (3-aminopropyl)triethoxysilane (APTES). To confirm the orientation of the amino groups in BBTA, a single crystal of 2,5-bis(6-nitrobenzo[d]oxazol-2-yl)thiophene (BBTN) was grown and examined by X-ray crystallography. The evidence of successful intercalation of BBTA into the nanochannels of ZL was provided by fluorescence spectrometry, gas sorption and fluorescence microscopy. BBTA showed a Stokes shift of 6641 cm⁻¹ (157 nm) in ethanol and 4611 cm⁻¹ (93 nm) in toluene. The BBTA-ZL composite (BBTA-ZL-s) showed a Stokes shift of 5677 cm⁻¹ (123 nm) in toluene, and 5450 cm⁻¹ (124 nm) in ethanol. In addition, the degree of loading was determined and stability against leaching was confirmed. We report the synthesis of this novel composite dye material with potential applications where free dyes are not applicable and which retains a large Stokes shift, independent of its chemical environment.

Natural dyes and pigments are currently sought by industries as environmentally friendly alternatives for the dyestuff markets. As source of direct green coloration, Psiadia altissima, an endemic fast-growing species from Madagascar, is used by the local population to dye silk and raffia fibers. It is also known for its phytochemical and biological properties, and ecological adaptability. The chemical compound responsible for the coloration and the reaction to obtain the green dyes has never been investigated to date. This current study aims to understand these dyeing properties by validating the use of P. altissima to dye fibers green. Extraction and dyeing tests were conducted with five different types of natural fibers followed by the characterization of the stability of the coloration. Chemical composition of the extracts, especially the compounds responsible for the green dye were determined by fractionation, chromatography and NMR spectroscopy. Natural dyeing gives the expected green hues on wool with good wash fastness. The green coloration has been identified to originate from an oxidation of dicaffeoylquinic acids under alkaline conditions on proteinic fibers. These results highlight the potential of P. altissima as a promising sustainable source of green dye for the textile industry.