Infoscience

Thesis

Bioinspired Selective Surface Deposition of Fragrance Delivery Systems

The perception of pleasantness€ in many of the consumer goods is provided by volatile chemical compounds called fragrances. While the volatility of fragrances is essential to provide a pleasant olfactory response, it presents at the same time a technological problem, such that their premature evaporation and degradation may occur prior to the application during the storage. Another crucial aspect that affects the performance of the consumer goods is the deposition of these delivery systems to the target of interest. The potential strategies to improve the deposition of fragrance delivery systems are much less explored compared to their preparation and predominantly based on the physiochemical optimization of the surface/interface properties, such as hydrophobicity and charge of the existing delivery systems. However, the extent of depositions achieved using these strategies are typically modest. Phage display is an in vitro evolutionary selection technique that is widely used to identify substrate selective short peptide ligands. Although it has been predominantly used to isolate biomolecule binding ligands, its scope has been expanded in the last decade and it has also found use to identify €œhard and €œsoft material binders. From this aspect, phage display may also provide short peptide ligands that can bind to i. e. cotton and hair surfaces under laundry and hair wash conditions. These ligands can be considered as a €œtool€ to improve the deposition of any fragrance delivery system upon their chemical incorporation via orthogonal functional groups. This Thesis aims to explore the feasibility of phage display identified peptides to selectively deposit fragrance delivery systems on cotton fabric and human hair surfaces and it can be subdivided into 4 Chapters. Chapter 1 provides a summary for the identification and characterization of €œsoft matter binding peptides via phage display. Herein, soft matter will be subdivided into three general classes: synthetic polymers, small organic molecules and natural polymers. Chapter 2 proposes a general synthetic method for the preparation of water soluble peptide-polymer conjugates that proceeds at mild conditions without the requirement of peptide protecting groups. Chapter 3 describes the preparation of fragrance delivery systems that can selectively deposit onto cotton fabric under laundry wash conditions. The Chapter will first show the identification of cotton fabric binding peptides via phage display experiments. In the next steps, the strongest cotton binding peptide will be incorporated into two different model fragrance delivery systems that are based on linear polymers and nanoparticles. Chapter 4 applies the general strategy described in Chapter 3 to a more challenging task: Selectively depositing fragrance delivery systems onto hair under shampoo conditions. First, the feasibility of phage display to identify hair binding peptides under shampoo conditions will be demonstrated. Subsequently, two of the peptide-polymer conjugates described in Chapter 2 will be used as a model for hair targeting fragrance delivery systems. In the final section, the influence of the stringency of the shampoo conditions as well as the steric hindrance in the peptide terminal domains to the deposition of these peptides onto hair will be assessed.

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