1
|
Konnova S, Fakhrullin R, Akhatova F, Lama N, Lvov Y, Cavallaro G, Lazzara G, Fakhrullin R. Magnetic coiffure: Engineering of human hair surfaces with polyelectrolyte-stabilised magnetite nanoparticles. CHEMICAL ENGINEERING JOURNAL ADVANCES 2022. [DOI: 10.1016/j.ceja.2022.100389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
|
2
|
Weiand E, Ewen JP, Koenig PH, Roiter Y, Page SH, Angioletti-Uberti S, Dini D. Coarse-grained molecular models of the surface of hair. SOFT MATTER 2022; 18:1779-1792. [PMID: 35112700 DOI: 10.1039/d1sm01720a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We present a coarse-grained molecular model of the surface of human hair, which consists of a supported lipid monolayer, in the MARTINI framework. Using coarse-grained molecular dynamics (MD) simulations, we identify a lipid grafting distance that yields a monolayer thickness consistent with both atomistic MD simulations and experimental measurements of the hair surface. Coarse-grained models for fully-functionalised, partially damaged, and fully damaged hair surfaces are created by randomly replacing neutral thioesters with anionic sulfonate groups. This mimics the progressive removal of fatty acids from the hair surface by bleaching and leads to chemically heterogeneous surfaces. Using molecular dynamics (MD) simulations, we study the island structures formed by the lipid monolayers at different degrees of damage in vacuum and in the presence of polar (water) and non-polar (n-hexadecane) solvents. We also use MD simulations to compare the wetting behaviour of water and n-hexadecane droplets on the model surfaces through contact angle measurements, which are compared to experiments using virgin and bleached hair. The model surfaces capture the experimentally-observed transition of the hair surface from hydrophobic (and oleophilic) to hydrophilic (and oleophobic) as the level of bleaching damage increases. By selecting surfaces with specific damage ratios, we obtain contact angles from the MD simulations that are in good agreement with experiments for both solvents on virgin and bleached human hairs. To negate the possible effects of microscale curvature and roughness of real hairs on wetting, we also conduct additional experiments using biomimetic surfaces that are co-functionalised with fatty acids and sulfonate groups. In both the MD simulations and experiments, the cosine of the water contact angle increases linearly with the sulfonate group surface coverage with a similar slope. We expect that the proposed systems will be useful for future molecular dynamics simulations of the adsorption and tribological behaviour of hair, as well as other chemically heterogeneous surfaces.
Collapse
Affiliation(s)
- Erik Weiand
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK.
- Institute of Molecular Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
- Thomas Young Centre for the Theory and Simulation of Materials, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
| | - James P Ewen
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK.
- Institute of Molecular Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
- Thomas Young Centre for the Theory and Simulation of Materials, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
| | - Peter H Koenig
- Corporate Functions Analytical and Data & Modeling Sciences, Mason Business Center, The Procter and Gamble Company, Cincinnati, 45224 Ohio, USA
| | - Yuri Roiter
- Corporate Functions Analytical and Data & Modeling Sciences, Mason Business Center, The Procter and Gamble Company, Cincinnati, 45224 Ohio, USA
| | - Steven H Page
- Corporate Functions Analytical and Data & Modeling Sciences, Mason Business Center, The Procter and Gamble Company, Cincinnati, 45224 Ohio, USA
| | - Stefano Angioletti-Uberti
- Institute of Molecular Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
- Thomas Young Centre for the Theory and Simulation of Materials, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
- Department of Materials, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
| | - Daniele Dini
- Department of Mechanical Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK.
- Institute of Molecular Science and Engineering, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
- Thomas Young Centre for the Theory and Simulation of Materials, Imperial College London, South Kensington Campus, SW7 2AZ London, UK
| |
Collapse
|
3
|
Luengo GS, Fameau AL, Léonforte F, Greaves AJ. Surface science of cosmetic substrates, cleansing actives and formulations. Adv Colloid Interface Sci 2021; 290:102383. [PMID: 33690071 DOI: 10.1016/j.cis.2021.102383] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/22/2022]
Abstract
The development of shampoo and cleansing formulations in cosmetics is at a crossroads due to consumer demands for better performing, more natural products and also the strong commitment of cosmetic companies to improve the sustainability of cosmetic products. In order to go beyond traditional formulations, it is of great importance to clearly establish the science behind cleansing technologies and appreciate the specificity of cleansing biological surfaces such as hair and skin. In this review, we present recent advances in our knowledge of the physicochemical properties of the hair surface from both an experimental and a theoretical point of view. We discuss the opportunities and challenges that newer, sustainable formulations bring compared to petroleum-based ingredients. The inevitable evolution towards more bio-based, eco-friendly ingredients and sustainable formulations requires a complete rethink of many well-known physicochemical principles. The pivotal role of digital sciences and modelling in the understanding and conception of new ingredients and formulations is discussed. We describe recent numerical approaches that take into account the specificities of the hair surface in terms of structuration, different methods that study the adsorption of formulation ingredients and finally the success of new data-driven approaches. We conclude with practical examples on current formulation efforts incorporating bio-surfactants, controlling foaming and searching for new rheological properties.
Collapse
|
4
|
Cheong LZ, Zhao W, Song S, Shen C. Lab on a tip: Applications of functional atomic force microscopy for the study of electrical properties in biology. Acta Biomater 2019; 99:33-52. [PMID: 31425893 DOI: 10.1016/j.actbio.2019.08.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/17/2019] [Accepted: 08/13/2019] [Indexed: 12/11/2022]
Abstract
Electrical properties, such as charge propagation, dielectrics, surface potentials, conductivity, and piezoelectricity, play crucial roles in biomolecules, biomembranes, cells, tissues, and other biological samples. However, characterizing these electrical properties in delicate biosamples is challenging. Atomic Force Microscopy (AFM), the so called "Lab on a Tip" is a powerful and multifunctional approach to quantitatively study the electrical properties of biological samples at the nanometer level. Herein, the principles, theories, and achievements of various modes of AFM in this area have been reviewed and summarized. STATEMENT OF SIGNIFICANCE: Electrical properties such as dielectric and piezoelectric forces, charge propagation behaviors play important structural and functional roles in biosystems from the single molecule level, to cells and tissues. Atomic force microscopy (AFM) has emerged as an ideal toolkit to study electrical property of biology. Herein, the basic principles of AFM are described. We then discuss the multiple modes of AFM to study the electrical properties of biological samples, including Electrostatic Force Microscopy (EFM), Kelvin Probe Force Microscopy (KPFM), Conductive Atomic Force Microscopy (CAFM), Piezoresponse Force Microscopy (PFM) and Scanning ElectroChemical Microscopy (SECM). Finally, the outlook, prospects, and challenges of the various AFM modes when studying the electrical behaviour of the samples are discussed.
Collapse
|
9
|
Velasco MVR, Baby AR, Sarruf FD, Kaneko TM, Samad RE, Vieira Júnior ND, de Freitas AZ. Prospective ultramorphological characterization of human hair by optical coherence tomography. Skin Res Technol 2009; 15:440-3. [DOI: 10.1111/j.1600-0846.2009.00386.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Velasco MVR, Dias TCDS, Freitas AZD, Júnior NDV, Pinto CASDO, Kaneko TM, Baby AR. Hair fiber characteristics and methods to evaluate hair physical and mechanical properties. BRAZ J PHARM SCI 2009. [DOI: 10.1590/s1984-82502009000100019] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hair thread is a natural fiber formed by keratin, a protein containing high concentration of sulfur coming from the amino acid cystine. The main physical proprieties of the hair depend mostly on its geometry; the physical and mechanical properties of hair involve characteristics to improve: elasticity, smoothness, volume, shine, and softness due to both the significant adherence of the cuticle scales and the movement control (malleability), as well as the easiness of combing, since they reduce the fibers static electricity. The evaluation of these effects on hair may be carried out by several methods, as: optical and electron microscopy, mechanical resistance measuring, shine evaluation and optical coherence tomography (OCT).
Collapse
|