Initiating fibro-proliferation through interfacial interactions of myoglobin colloids with collagen in solution

- Lyophilisomes of globular protein, Myoglobin have been designed at pH 4.5 and 7.5.
- Surface charge distributions in these lyophilisomes are important to control intermolecular electrostatic interactions with collagen, a fibrous protein.
- Rheological properties and the chemical potential at the interface of Myoglobin lyophilisomes-collagen solution can help model fibro-proliferation.

This work examines fibro-proliferation through interaction of myoglobin (Mb), a globular protein with collagen, an extracellular matrix fibrous protein. Designed colloids of Mb at pH 4.5 and 7.5 have been mixed with collagen solution at pH 7.5 and 4.5 in different concentrations altering their surface charges. For the Mb colloids, 100-200 nm sizes have been measured from Transmission electron micrographs and zeta sizer. CD spectra shows a shift to beta sheet like structure for the protein in the colloids. Interaction at Mb/Collagen interface studied using Dilational rheology, Quartz crystal microbalance with dissipation and Differential Scanning calorimetry show that the perturbation is not only by the charge compensation arising from the difference in pH of the colloids and collagen, but also by the organized assembly of collagen at that particular pH. Results demonstrate that positive Mb colloids at pH 4.5, having more% of entrained water stabilize the collagen fibrils (pH 7.5) around them. Ensuing dehydration leads to effective cross-linking and inherently anisotropic growth of fibrils/fibres of collagen. In the case of Mb colloids at pH 7.5, the fibril formation seems to supersede the clustering of Mb suggesting that the fibro-proliferation is both pH and hydrophilic-hydrophobic balance dependent at the interface.

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