Welcoming Remarks

Silk fibroin proteins purified from Bombyx mori silkworm cocoons are used to create biopolymer solutions, forming versatile biomaterials.^[1] These proteins offer tunable mechanical properties, limited inflammatory response activation, non-thrombogenicity, and controlled biodegradability.^[2] Silk scaffolds are useful in tissue engineering and wound healing due to features like enzymatic degradation and the potential for cellular integration. Customizable silk fibroin sponges demonstrate adjustable characteristics such as pore size, elastic modulus, and crystalline content, showing promise as a scaffold to facilitate tissue regeneration. Adjusting fabrication parameters such as freezing temperature, water annealing time, and degumming time enables fine-tuning of enzymatic degradation rates of silk scaffolds.^[3] This research quantifies the relationship between parameter alterations and enzyme degradation rates via a kinetic model. Previous work shows faster degradation rates with lower silk fibroin molecular weight and lower polymer concentrations. Experimental mass loss data over time supports this hypothesis. However, predicting in vivo scaffold degradation remains challenging. This study compares discrete and continuous sampling techniques for monitoring the degradation of sponges over time, varying formulation parameters like extraction time and silk concentration. While we have explored methodologies before, our results show that use of the oven to dry the samples quickly altered the structural integrity and crystalline composition of the scaffolds. We showed this by evaluating scanning electron microscopy images over time during the degradation process when using either discrete or continuous sampling methods, as shown in Figure 1. While the continuous method has the advantage of following the same sample over the course of the experiment, our data fit a modified first order reaction rather than the anticipated Michaelis-Menten kinetic model, leading us to further explore the role of structural changes on the resulting data. In this study, we hypothesized that utilizing the discrete method would eliminate changes in sponge structure due to the elimination of the repeated use of oven dried samples. We then confirmed that the data fit a Michaelis-Menten kinetic model. This approach improves the accuracy of degradation prediction and provides insight into the influence of low heat (40^oC) on protein secondary structure in porous silk sponges.