Glycosaminoglycan stiffness evaluation by means of molecular mechanics approach for tendon functional analysis

Recent studies have shown that the glycosaminoglycans (GAGs) bound to decorin act like bridges between contiguous collagen fibrils connecting adjacent fibril every 64-68 nm; this architecture would suggest their possible role in providing the mechanical integrity of the tendon structure. The present work investigates the GAG stiffens and the ability of decorin GAGs to transfer forces between adjacent fibrils. A typical GAG associated to decorin - chondroitin-6-sulphate - has been evaluated through the molecular mechanics approach. The obtained GAG stiffness is piece-wise linear with an initial plateau at low strains (<800 %) and a high stiffness region (3.1 10^-11 N/nm) afterwards. By introducing the calculated GAG stiffness in a multi-fibril model, miming the tendon architecture, the stress-strain behaviour of the collagen fibre has been also calculated.