titanium and polytetrafluoroethylene, with good biocompatibility [6; 7; 8], aiming to maintain their structural integrity and the space beneath the membrane for a sufficient period. The main advantage is considered to be their predictability in terms of performance, and, hence, a reduced risk of long-term complications [9]. The main drawback in using this type of membrane is the necessity for its removal with a second-stage surgery. On the other hand, the advantage of bioabsorbable membranes, either synthetic (aliphatic polyesters) or natural (collagen), is their biochemical pathway resorption over time [1]. However, their main disadvantage is their unpredictability in terms of degree of resorption, with possible consequences regarding lack of rigidity [10; 11; 12; 13].  
Being the main component of periodontal and connective tissues, collagen-based degradable membranes are extensively used for GTR or GBR procedures. Collagen can be extracted industrially from bovine and porcine dermis and tendons, but during the manufacturing processes, significant structural changes may occur [14; 15]. However, extracted collagen can be modified according to the medical purpose, resulting different forms adapted to medical applications such as GBR and GTR [14; 16].  
Different types of collagen membranes, with different degrees of biodegradability, have been developed in the last decade, in order to optimize treatment strategies [1; 2; 10; 17].  
The ongoing research in this field aims to develop an ideal membrane for GBR and GTR; every membrane type offers both advantages and disadvantages, but none exactly match the need of the final user--the clinician or the dentist. Continuous research is dedicated to this topic, based on the understanding of the benefits and limitations.  
On the other hand, plasma rich in growth factors (PRGF) of autologous origin have previously been demonstrated to introduce several advantages, including the enhancement and acceleration of bone regeneration and, additionally, fast and predictable soft tissue healing [18; 19; 20; 21]. Once the platelets become activated, the growth factors and cytokines within the alpha and dense granules are released.  
The main growth factors detected in PRGF formulations are: transforming growth factor (TGF\(\beta\)1), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF-1), and platelet-derived growth factor (PDGR). Additionally, the cytokines and chemokines involved in the healing process and immunomodulatory pathway, namely interleukin (IL-1\(\beta\), IL-8), monocyte chemotactic proteins (MCP-1, MCP-2 and MCP-3), and normal T cell (RANTES), can be quantified in activated PRGF. The quality of PRGF formulations depends on the preparation methodologies and can be assessed by quantification of these therapeutic molecules. The regulation and kinetic release of all these multiple growth factors may require, in some therapeutic conditions, their association or incorporation into biomaterials or drug delivery systems.  
By using these concepts, the aim of our study was to evaluate the properties of modified collagen membranes by incorporation of PRGF into different types of commercial collagen membranes, and to investigate the resulting structural and morphological details and mechanical properties. A significant view of the mechanical behavior at nanoscale will be a valuable approach in providing clinicians with as much data as possible to help them in a successful comparison and, at the same time, to a better selection with respect to their placement and working condition [14].  
The performances of modified membranes were assessed in a comparative study, by attenuated total reflection (ATR) Fourier transform infrared (FTIR) spectroscopy, nanoindentation, atomic force microscopy (AFM) and scanning electron microscopy (SEM), starting from different commercially available collagen membranes.