Glow-in-the-Dark Patterned PET Nonwoven Using Air-Atmospheric Plasma Treatment and Vitamin B2-Derivative (FMN).

Flavin mononucleotide (FMN) derived from Vitamin B2, a bio-based fluorescent water-soluble molecule with visible yellow-green fluorescence, has been used in the scope of producing photoluminescent and glow-in-the-dark patterned polyester (PET) nonwoven panels. Since the FMN molecule cannot diffuse inside the PET fiber, screen printing, coating, and padding methods were used in an attempt to immobilize FMN molecules at the PET fiber surface of a nonwoven, using various biopolymers such as gelatin and sodium alginate as well as a water-based commercial polyacrylate. In parallel, air atmospheric plasma activation of PET nonwoven was carried for improved spreading and adhesion of FMN bearing biopolymer/polymer mixture. Effectively, the plasma treatment yielded a more hydrophilic PET nonwoven, reduction in wettability, and surface roughness of the plasma treated fiber with reduced water contact angle and increased capillary uptake were observed. The standard techniques of morphological properties were explored by a scanning electron microscope (SEM) and atomic force microscopy (AFM). Films combining each biopolymer and FMN were formed on PS (polystyrene) Petri-dishes. However, only the gelatin and polyacrylate allowed the yellow-green fluorescence of FMN molecule to be maintained on the film and PET fabric (seen under ultraviolet (UV) light). No yellow-green fluorescence of FMN was observed with sodium alginate. Thus, when the plasma-activated PET was coated with the gelatin mixture or polyacrylate bearing FMN, the intense photoluminescent yellow-green glowing polyester nonwoven panel was obtained in the presence of UV light (370 nm). Screen printing of FMN using a gelatin mixture was possible. The biopolymer exhibited appropriate viscosity and rheological behavior, thus creating a glow-in-the-dark pattern on the polyester nonwoven, with the possibility of one expression in daylight and another in darkness (in presence of UV light). A bio-based natural product such as FMN is potentially an interesting photoluminescent molecule with which textile surface pattern designers may create light-emitting textiles and interesting aesthetic expressions.

Toward Bioluminescent Materials by Plasma Treatment of Microfibrous Nonwovens, Followed by Immobilization of One or Both Enzyme(s) (Luciferase and FMN Reductase) Involved in Luminescent Bacteria.

Bioluminescent living organisms emit light through a specific biocatalyzed reaction involving a luciferin substrate and a luciferase enzyme. The present work investigated the possibility of creating optimal luminescence by immobilization of one or both the enzymes Luciferase (Luc) and FMN reductase (Red) involved in a bioluminescent bacterial system onto a plasma-activated microfibrous PET nonwoven. Parameters affecting the catalytic activity and efficiency of the bacterial system in aqueous medium were determined by luminescence intensity measurements using a luminometer. Two types of plasma, air atmospheric plasma (ATMP) and cold remote plasma (CRPNO) treatment, were used to activate the PET nonwoven. Further, one or both enzyme(s) were immobilized using a physical adsorption technique, without or with the use of natural biopolymers (gelatin and starch) and bovine serum albumin-BSA protein, to improve enzyme stability and activity. Coimmobilization of both Red and Luc enzymes on the CRPNO plasma-activated nonwoven in the presence of BSA led to the maximum luminescence. As high as 60,000 RLU equivalent to that of an LED light used for calibration was observed and showed stable intensity up to 6 min. Fiber surface analysis was tested using wettability tests (water contact angle and capillary uptake), while scanning electron microscopy, atomic force microscopy, and electron spectroscopy for chemical analysis showed changes in fiber surface morphology and chemical functional groups. A considerable increase in "N" atom content after coimmobilization of enzymes in the presence of BSA was detected. This study is the first successful attempt to use a biomimetic strategy for immobilization of enzymes involved in bacterial luminescence on a plasma-activated microfibrous nonwoven in an attempt to attain bioluminescent materials.

Color-changing intensified light-emitting multifunctional textiles via digital printing of biobased flavin.

Flavin mononucleotide (biobased flavin), widely known as FMN, possesses intrinsic fluorescence characteristics. This study presents a sustainable approach for fabricating color-changing intensified light-emitting textiles using the natural compound FMN via digital printing technologies such as inkjet and chromojet. The FMN based ink formulation was prepared at 5 different concentrations using water and glycerol-based systems and printed on cotton duck white (CD), mercerized cotton (MC), and polyester (PET) textile woven samples. After characterizing the printing inks (viscosity and surface tension), the photophysical and physicochemical properties of the printed textiles were investigated using FTIR, UV/visible spectrophotometry, and fluorimetry. Furthermore, photodegradation properties were studied after irradiation under UV (370 nm) and visible (white) light. Two prominent absorption peaks were observed at around 370 nm and 450 nm on K/S spectral curves because of the functionalization of FMN on the textiles via digital printing along with the highest fluorescence intensities obtained for cotton textiles. Before light irradiation, the printed textiles exhibited greenish-yellow fluorescence at 535 nm for excitation at 370 nm. The fluorescence intensity varied as a function of the FMN concentration and the solvent system (water/glycerol). With 0.8 and 1% of FMN, the fluorescence of the printed textiles persisted even after prolonged light irradiation; however, the fluorescence color shifted from greenish-yellow color to turquoise blue then to white, with the fluorescence quantum efficiency values (φ) increasing from 0.1 to a value as high as 1. Photodegradation products of the FMN with varying fluorescence wavelengths and intensities would explain the results. Thus, a color-changing light-emitting fluorescent textile was obtained after prolonged light irradiation of textile samples printed using biobased flavin. Furthermore, multifunctional properties such as antibacterial properties against E. coli were observed only for the printed cotton textile while increased ultraviolet protection was observed for both cotton and polyester printed fabrics for the high concentration of FMN water-based and glycerol-based formulations. The evaluation of fluorescence properties using digital printing techniques aimed to provide more sustainable solutions, both in terms of minimum use of biobased dye and obtaining the maximum yield.

Study of photoluminescence property on cellulosic fabric using multifunctional biomaterials riboflavin and its derivative Flavin mononucleotide.

Flavins are ubiquitous in nature and participate in various biochemical reactions mainly in the form of coenzyme Flavin mononucleotide (FMN) or as precursor such as Riboflavin (RF). Both flavins, RF and FMN are multifunctional bio-based molecules yielding yellow coloration and exhibit photoluminescence, UV protection, and redox properties. The aim of the present research study was to investigate the diffusion method as a technique to obtain photoluminescent cellulosic fabric using multifunctional RF and FMN. The photoluminescent moiety RF and FMN exhibited three maximum absorbance peaks at about 270 nm, 370 nm and 446 nm in aqueous solution at pH 7. The solutions of RF and FMN with concentration 4% and 20% (owf) at pH 7 were prepared and used in diffusion method for cellulosic fabric dyeing. The study involved the determination of color performance and evaluation of luminescence property of the dyed fabric using UV-visible spectrophotometer and photoluminescence spectroscopy, respectively. Under monochromatic UV lamp exposure emitting at 370 nm, the dyed fabric showed an intense emission of greenish yellow color, which was later confirmed by the intense photoluminescence observed at a wavelength of about 570 nm. The study demonstrates the theoretical evaluation of quantum efficiency (φ) obtaining maximum φ value of 0.28. Higher color strength value and improved wash fastness were obtained by treatment with different biobased mordants such as tannic acid and citric acid as well as calcium chloride for both RF and FMN. Additionally, ultraviolet (UV) protection ability for both RF and FMN dyed fabric were determined and showed UPF factor of 50+ and 35 respectively. The work allowed us to explore the photoluminescence property of riboflavin and Flavin mononucleotide for its application in the field of textiles as a new scope of producing photoluminescent textile along with multifunctional properties such as coloration and UV protection.