Porous vaterite containers of 400 nm size are studied with respect to intracellular drug delivery applications. A generic crystal phase transition from vaterite to calcite serves as a novel payload release mechanism, which reveals a delayed burst-release. This will permit control of the pharmacokinetics allowing for applications like preventive drug administration or scheduled application of pharmaceuticals during long term therapy. Experiments with two types of payloads, providing different molecular weights and zeta-potentials, demonstrate a flexible way of tailoring the payload delivery time via the molecular properties of the cargo. A dual in vitro cellular uptake experiment with human ovarian carcinoma cells ES2 and human fibroblasts MRC5 shows no cytotoxicity, no influence on cell viability, and fast penetration of substance-loaded containers into cells. Flow cytometry analysis proves high uptake rates and 3D microscopy analysis reveals the intracellular distribution

In spite of commercially available products, the complete and sustained repair of damaged articular cartilage still presents various challenges. Among biomaterials proposed for cartilage repair, silk fibroin (SF) has been recently proposed as a material template for porous scaffolds cultured with chondrocytes and investigated in static and dynamic conditions. In addition to fibroin-based constructs, literature has reported that the combination of hyaluronic acid (HA) with other scaffold materials can protect the chondral phenotype and the cells in vitro response to the scaffold. In this study, the effect of the addition of HA on the physical properties of SF sponges, with and without cross-linking with genipin, was investigated. Salt-leached scaffolds were characterized in terms of morphology and structural and physical properties, as well as mechanical performance. Un-cross-linked sponges resulted in the physical separation of highly hydrophilic HA from the SF, while cross-linking prevented this phenomenon, resulting in a homogeneous blend. The presence of HA also influenced fibroin crystallinity and tended to decrease the cross-linking degree of the scaffolds when compared to the pure SF material.

Silk fibroin and sericin have been widely used as a biomaterial for many different purposes. In this study, the properties of crosslinked fibroin/sericin 90/10 films have been investigated using two different crosslinkers poly(ethylene glycol) diglycidyl ether 600 (PEG-DE) and genipin. The films were characterized by molecular weight, fibroin conformation, crystallinity, and thermal stability. Both PEG-DE and genipin cross-linkers stabilized the random/α-helix structures in the fibroin and prevented phase separation between fibroin and sericin that occurs with non-crosslinked materials. The genipin crosslinked film displayed highest elongation at break and tensile strength. The in vitro cytotoxicity of the materials was assessed by lactate dehydrogenase activity and the viability was based on the tetrazolium salt and WST-1 tests. All films exhibited good biocompatibility and supported cell adhesion and proliferation.