**Elisa Bacelo 1,2, Marta Alves da Silva 1,2, Cristina Cunha 2,3, Susana Faria 4, Agostinho Carvalho 2,3, Rui L. Reis 1,2,5, Albino Martins 1,2,\* and Nuno M. Neves 1,2,5**


Received: 19 February 2019; Accepted: 28 March 2019; Published: 8 April 2019

**Abstract:** Rheumatoid arthritis (RA) is an autoimmune disease that affects the synovial cavity of joints, and its pathogenesis is associated with an increased expression of pro-inflammatory cytokines, namely tumour necrosis factor-alpha (TNF-α). It has been clinically shown to have an adequate response to systemic administration of TNF-α inhibitors, although with many shortcomings. To overcome such limitations, the immobilization of a TNF-α antibody on a nanofibrous substrate to promote a localized action is herein proposed. By using this approach, the antibody has its maximum therapeutic efficacy and a prolonged therapeutic benefit, avoiding the systemic side-effects associated with conventional biological agents' therapies. To technically achieve such a purpose, the surface of electrospun nanofibers is initially activated and functionalized, allowing TNF-α antibody immobilization at a maximum concentration of 6 μg/mL. Experimental results evidence that the biofunctionalized nanofibrous substrate is effective in achieving a sustained capture of soluble TNF-α over time. Moreover, cell biology assays demonstrate that this system has no deleterious effect over human articular chondrocytes metabolism and activity. Therefore, the developed TNF-capturing system may represent a potential therapeutic approach for the local management of severely affected joints.

**Keywords:** antibody immobilization; electrospun nanofibers; TNF-α capture; human articular chondrocytes; rheumatoid arthritis
