International Journal of Basic and Applied Biology Print ISSN: 2394-5820, Online ISSN: 2349-2539, Volume 2, Number 6; July-September, 2015, pp. 364-367 © Krishi Sanskriti Publications http://www.krishisanskriti.org/ijbab.html Characterization of Fibrous Scaffold using Quantitative Nano-Mechanical Mapping Mode of Atomic Force Microscope Mohammad A. Hussain 1 , Adnan Memic 2 , Nazeeh S. Alothmani 3 , Rabah W. Al-dhaheri 4 , Faten Al-hazmi 5 , Hani A. Alhadrami 6 and Ali Khademhosseini 7 1,2,3,4,5,6 KAU, Jeddah, KSA 7 Harvard-MIT, USA E-mail: 1 mhussain2@kau.edu.sa, 2 amemic@kau.edu.sa, 3 nothmany@kau.edu.sa, 4 raldhaheri@kau.edu.sa, 5 fialhazmi@kau.edu.sa, 6 hanialhadrami@kau.edu.sa, 7 khademh@gmail.com, Abstract—Electrospun polymeric fibers with nano and submicron diameters amalgamated with inorganic nanoparticles, in particular, those constructed with uniform reinforcements can be used as scaffolds in tissue engineering. Importantly it warrants a characterization of their mechanical properties particularly at the nanoscale. The PeakForce Quantitative NanoMechanics (PF-QNM) AFM mode allows to probe nanomechanical properties of the material namely, DMT modulus, adhesion, dissipation and deformation, at the same time along with topographical imaging. In this paper we present results of PF-QNM characterization of three kinds of electrospun nanofibers made from a 1:1 blend of two polymers: PCL and PMMA with further addition of inorganic nanoparticles (Ag and ZnO) at three ratios thereby adding another degree of nanocomposition to the resulting nanocompoite nanofiber scaffold. The results showed the inorganic nanoparticles Ag and ZnO, with different shapes and sizes, appearing at the surface of the nanofibers. Heterogeneous Ag and ZnO nanoparticle distribution was observed on the nano fiber mesh. The Ag and ZnO contents were different at different locations along the nanofibers lengths based on their ratios in three different types of nanofiber mesh. The different ratios of Ag:ZnO inorganic nanoparticles affected the DMT Modulus as well as hydrophilic nature of the three kinds of nanofiber surfaces. Increasing ZnO amount increased both the hardness and water contact angle of the nanofiber mesh. For the same increase in the (Ag:ZnO) ratio, ZnO doubled the %increase in hydrophobicity as compared to Ag. From Ag:ZnO (30:30) to (100:30) increased the water contact angle by 8% while altering the ratio (30:100) increased it by 16%. The average DMT modulus was 0.62 ± 0.26 MPa for control mesh, 2.22 ± 0.61 MPa for Ag:ZnO (30:30), 5.62 ± 1.39 MPa for Ag:ZnO (100:30), and 63.87 ± 81.82 MPa for Ag:ZnO (30:100) mesh. 1. INTRODUCTION The last decade has seen an increasing trend in designing scaffolds for tissue engineering from biodegradable polymeric fibers with nano and submicron diameters specifically produced by electrospinning method. Partly successes in using such scaffolds are attributable to structural similarity to the extracellular matrix (ECM), convenient porosity for cellular proliferation, high surface area to volume ratio, reduced immunogenicity and biodegradability among others [1]. After implantation of such scaffolds, in biomechanical environment of the body, however the fibers in the scaffolds are subjected to stresses and strains in physiological conditions, thereby standing a chance to permanent deformation or even failure to scaffold structure. Therefore, there is a pressing need to characterize their mechanical properties, especially at the nanoscale as well as to assess resulting surface properties such as wettability. 1.1 Nano-mechanical properties. Atomic force microscopy (AFM) in the family of scanning probe microscopy has emerged as a promising tool with a host of powerful techniques that have been employed in imaging of the components of biomaterials scaffolds and probing selected mechanical properties under physiological conditions [2-4]. The PeakForce Quantitative NanoMechanics (PF-QNM) is relatively a new addition to the host of techniques allowing to measure nano-mechanical properties of the materials including reduced Young`s modulus, adhesion, dissipation, and deformation concurrently with topographical height imaging [5]. 1.2 Wettability. Wettability pertains to the interaction between solid and fluid phases at the interface. Strictly the contact angle of the fluid with the solid phase at which the liquid–vapor interface meets the solid–liquid interface, explains the wettability. This in turn is determined by a force balance between adhesive and cohesive forces. An increasing tendency of a drop to spread out over a flat, decreases the contact angle, thereby providing an inverse measure of wettability. A contact angle less than 90° (low contact angle) usually indicates that wetting of the