Fluid Release Evaluation of BNC and PLGA-Loaded BNC

Native and PLGA-loaded BNC were investigated for their fluid-releasing capabilities using a method previously reported by Zahel et al. [42 (link)]. Briefly, an aqueous solution containing 142 mmol L⁻¹ sodium chloride as well as 2.5 mmol L⁻¹ calcium chloride (both Carl Roth) was prepared. Subsequently, 35% (w/w) gelatin (Bloom 180, Carl Roth) was suspended in this solution and incubated at 60 °C until fully dissolved. Afterward, Petri dishes with a diameter of 100 mm were filled with 37 g of the gelatin solution each, tightly sealed, and incubated at 25 °C for 3 h to allow the gelation of gelatin. Subsequently, the Petri dishes were weighed, the BNC samples were placed on the gelatin surface afterward and the dishes were tightly sealed. After 48 h of incubation, the BNC samples were removed, and the dishes were weighed again. The fluid release (FR) was calculated according to Equation (5):
where m_after represents the weight of the Petri dishes after incubation, m_before the weight of the Petri dishes before incubation, and A the contact area between BNC fleece and gelatin gel. Experiments were performed in triplicates and repeated once.