52 HAIR CARE No application 1 application 5 application 10 application
Figure 1: Fluorescence microscopy images of the peptide penetrating hair
Learn phase (iterative optimisation) The insights gleaned from the rigorous testing phase are critical for informing iterative optimisation. This continuous feedback loop allows researchers to fine-tune both the peptide design and the production parameters. For instance, if a peptide shows promising
binding but suboptimal strength, the design may be re-evaluated. Similarly, fermentation conditions - e.g. nutrient composition, temperature, pH, aeration - are adjusted to maximise peptide yield and ensure consistent quality.
The two main selection criteria driving this
optimisation are superior performance on hair (demonstrated efficacy) and high production efficiency (scalability and cost-effectiveness), ensuring the transition from laboratory discovery to a commercially viable product.
Scaling up Following successful optimisation at lab scale, the fermentation process is scaled up for industrial production. This involves cultivating the genetically modified microorganisms under carefully controlled, large-scale bioreactor conditions. Sugar serves as the primary carbon and
energy source, while nitrogen is supplied as a key component for microbial cell growth and subsequent keratin peptide biosynthesis. Maintaining an optimal environment for these microorganisms is essential for the efficient and high-quality production of this biomimetic ingredient at commercial volumes. The final stages involve advanced
purification and solubilisation techniques. After fermentation, downstream processing commences with harvesting the peptide- producing cells. A series of stringent purification steps
are then applied, utilising techniques such as chromatography and filtration, to isolate the keratin peptide at increasing levels of purity. This multi-stage purification ensures the removal of cellular debris, residual media components, and host cell proteins, leading to a highly pure active ingredient. Finally, hydrolysis is precisely controlled
to convert the purified keratin into the desired peptide sizes, specifically around an average molecular weight of ~900 Da. This precise peptide sizing is crucial for optimising the peptide’s penetration, binding and overall performance.
PERSONAL CARE September 2025 The final product is supplied as a 5% active
solution in water, preserved with benzyl alcohol, ensuring stability and ease of formulation. The resulting active is also 99% naturally derived (ISO 16128), vegan-suitable, phenoxyethanol-free, and EU/UK REACH compliant.
Mechanism of action: molecular- level interaction and keratin recharge The efficacy of this biomimetic keratin peptide is directly attributed to its molecular-level interaction with the hair. Unlike many traditional repair actives that primarily form a superficial film or provide temporary external repair, the peptide is designed to integrate seamlessly within the hair fibre. Its human hair-identical sequence allows it to specifically target and bind to regions within the hair’s cortex, effectively providing a ‘keratin recharge’. Hair keratin is composed of both α-keratins,
which form complex filament structures within the cortex and amorphous keratin associated proteins (KAPs) which surround the filaments and keep them stable. These structures are rich in cysteine residues which form crucial disulphide bonds that provide significant mechanical strength and stability to the hair. Damage from chemical treatments (e.g.
bleaching, colouring), heat styling, and mechanical stress (e.g. brushing, combing) can lead to the breakage of these disulphide bonds, as well as the degradation of peptide bonds. This results in weakened, brittle hair with compromised integrity and reduced mechanical properties. The biomimetic peptide, with its precise
structure, is designed to penetrate the cuticle and enter the hair cortex. Once inside, its unique sequence allows it to selectively bind facilitating a ‘recharge’ process where the peptide effectively supplements and stabilises the damaged keratin network. While not forming new covalent disulphide bonds in the same way as claimed by some first-generation bond builders, its integration enhances the overall structural cohesion and hydrophobicity of the keratin matrix. This leads to an improvement in the mechanical properties and thermal stability of the hair, mimicking the performance characteristics of healthy, undamaged hair.
Performance studies and data The performance benefits and molecular mechanism of the biomimetic peptide have been rigorously evaluated using a range of
market-leading laboratory tests, providing robust scientific substantiation for its claims.
Hair fibre penetration and keratin binding studies To directly visualise and quantify the interaction of the peptide with hair, a combination of advanced fluorescence imaging and targeted peptide binding assays was employed.
Fluorescence microscopy methodology The peptide was conjugated with 5(6)-carboxytetramethylrhodamine N-succinimidyl ester (TAMRA-SE), a fluorescent dye chosen for its yellow-orange emission (excitation ~540 nm; emission ~588 nm), minimising interference from the hair’s natural autofluorescence. Unbound dye was removed via washing and filtration to ensure fluorescence originated only from the bound peptide. The labelled peptide solution
(approximately 0.2%–0.7% active) was topically applied to hair fibres under three conditions: single, 5x, and 10x repeated applications. After each treatment cycle, fibres were rinsed to eliminate unbound protein. 20–30 treated fibres were embedded in ice and sectioned into 10 µm slices using a cryostat. Sections were mounted on slides for imaging using a Leica DM2500 with LAS X software. This approach enabled precise visualisation
and localisation of the fluorescently labelled peptide within the hair fibre structure, demonstrating its ability to recharge keratin internally (Figure 1).
Peptide binding study methodology To delve deeper into the specific molecular interactions, a targeted peptide assay was developed. This methodology involved the systematic subdivision of full keratin amino acid sequences into smaller, synthetically produced peptide segments. Each of these synthesised peptide segments was subsequently immobilised onto the solid-phase substrate of individual wells within a 96-well microplate. Following immobilisation, each well
was treated with a solution containing a fluorescently tagged peptide and incubated under controlled conditions to facilitate peptide binding. To ensure removal of any non-bound material, the microplate underwent a rigorous washing procedure, repeated twice. The extent of peptide binding to the immobilised keratin fragments was then quantitatively assessed using a fluorescence microplate reader. The
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