Silk Fibroin Improves the Biological Properties of Egg White-Based Bioink for the Bioprinting of Tissue Engineering Materials.

Egg white (EW) is a common nutritious food with excellent heat gelation and biocompatibility, but its application in biomaterials is considerably limited. Silk fibroin (SF) is a protein-based fiber with both excellent mechanical properties and biocompatibility, and its application in biomaterials has attracted much attention. Here, the EW/SF composite scaffold was first synthesized with GMA-modified EW/SF composite bioink (G-EW/SF). When homogenized EW and SF were individually grafted with glycidyl methacrylate (GMA), the grafted EW (G-EW) and SF (G-SF) were mixed in different proportions and then added to I2959. The resulting G-EW/SF composite bioink could be bioprinted into various EW/SF composite scaffolds. Among them, the compressive modulus of EW/SF (50%) composite scaffolds incorporating 50% G-SF was significantly improved. It had a three-dimensional (3D) polypore structure with an average pore size of 61 µm and was mainly composed of ß-sheet structures. Compared with the EW scaffold alone, the thermal decomposition temperature of the EW/SF scaffold was 10 °C higher, and the residual rate after 9 days of enzymatic hydrolysis had increased by about 18%. The scaffold prolonged the sustained release of insulin and promoted the adhesion, growth, and proliferation of the L-929 cells. Therefore, the EW/SF composite scaffolds with good cell proliferation ability and certain mechanical properties can be used in different applications including cells, drugs, and tissues. These results provide new prospects for the application of the EW protein to medical tissue engineering materials.

Functional movement screen dataset collected with two Azure Kinect depth sensors.

This paper presents a dataset for vision-based autonomous Functional Movement Screen (FMS) collected from 45 human subjects of different ages (18-59 years old) executing the following movements: deep squat, hurdle step, in-line lunge, shoulder mobility, active straight raise, trunk stability push-up and rotary stability. Specifically, shoulder mobility was performed only once by different subjects, while the other movements were repeated for three episodes each. Each episode was saved as one record and was annotated from 0 to 3 by three FMS experts. The main strength of our database is twofold. One is the multimodal data provided, including color images, depth images, quaternions, 3D human skeleton joints and 2D pixel trajectories of 32 joints. The other is the multiview data collected from the two synchronized Azure Kinect sensors in front of and on the side of the subjects. Finally, our dataset contains a total of 1812 recordings, with 3624 episodes. The size of the dataset is 190 GB. This dataset provides the opportunity for automatic action quality evaluation of FMS.

Silk Protein Composite Bioinks and Their 3D Scaffolds and In Vitro Characterization.

This paper describes the use of silk protein, including fibroin and sericin, from an alkaline solution of Ca(OH)2 for the clean degumming of silk, which is neutralized by sulfuric acid to create calcium salt precipitation. The whole sericin (WS) can not only be recycled, but completely degummed silk fibroin (SF) is also obtained in this process. The inner layers of sericin (ILS) were also prepared from the degummed silk in boiling water by 120 °C water treatment. When the three silk proteins (SPs) were individually grafted with glycidyl methacrylate (GMA), three grafted silk proteins (G-SF, G-WS, G-ILS) were obtained. After adding I2959 (a photoinitiator), the SP bioinks were prepared with phosphate buffer (PBS) and subsequently bioprinted into various SP scaffolds with a 3D network structure. The compressive strength of the SF/ILS (20%) scaffold added to G-ILS was 45% higher than that of the SF scaffold alone. The thermal decomposition temperatures of the SF/WS (10%) and SF/ILS (20%) scaffolds, mainly composed of a ß-sheet structures, were 3 °C and 2 °C higher than that of the SF scaffold alone, respectively. The swelling properties and resistance to protease hydrolysis of the SP scaffolds containing sericin were improved. The bovine insulin release rates reached 61% and 56% after 5 days. The L929 cells adhered, stretched, and proliferated well on the SP composite scaffold. Thus, the SP bioinks obtained could be used to print different types of SP composite scaffolds adapted to a variety of applications, including cells, drugs, tissues, etc. The techniques described here provide potential new applications for the recycling and utilization of sericin, which is a waste product of silk processing.

Sodium N-lauryl amino acids derived from silk protein can form catanionic aggregates with cytarabine as novel anti-tumor drug delivery systems.

A sodium N-lauryl amino acids (shortly silk sericin surfactant, SSS) is synthesized with lauryl chloride and sericin amino acids recovered from silk industrial waste. The purpose of this study is to explore whether the sericin surfactant can be used as a potential drug delivery carrier. By controlling the proportion of cationic drugs, cytarabine hydrochloride (CH) and anionic SSS, the aggregation behavior, slow release capability and toxicological effects of catanionic aggregates or vesicles, formed through CH and SSS, have been investigated in detail. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and zeta potential analysis showed that the aggregate solution could form a stable vesicle structure when the mass fraction of CH is less than or equal to 0.3. The drug release results showed that the cumulative release rate of the catanionic aggregation solution with CH mass fraction of 0.2 reached a maximum at 18 h, being approximately 9 times greater than that of pure cytarabine. The CH/SSS aggregates had a significant sustained release effect compared with the control group. At the same time, vesicles formed by SSS and CH have better anti-tumor effects compared with the pure drug group. In summary, sericin surfactant from silk industrial waste has a potential use as a drug delivery carrier.

Silk sericin has significantly hypoglycaemic effect in type 2 diabetic mice via anti-oxidation and anti-inflammation.

The sericin protein from silk-processing waste added to the normal diet at 0.8% (g%) level was administered orally to type 2 diabetic (T2D) mice to investigate its hypoglycaemic effects and mechanism. The oral protein is in the form of silk sericin hydrolysate, obtained from a boiling treatment of 0.025% calcium hydroxide solution. The protein significantly decreased fasting blood glucose, fasting plasma insulin, and glycosylated serum protein levels; improved oral glucose tolerance and insulin tolerance, and enhanced antioxidative activities. The protein could ameliorate the pathological damage in pancreatic ß-cells and the liver tissue. It enhanced the expression of key proteins and enzymes, including insulin receptor, insulin receptor substrate, PI3K, phosphorylated-AKT, hepatic kinase, GLUT4, glycogen synthase, GSK3ß, GLK, PFK1, PKM2, and AMPKα, which are related to insulin metabolism and glycolysis. The protein also reduced the expression of G6Pase, PCK, and ACC, which are related to gluconeogenesis and lipid metabolism in the liver, and decreased the expression of TNF-α, IL-6, P65, and IKKß related to inflammation. In general, sericin could maintain normal glucose levels and regulate insulin secretion, insulin and lipid metabolism, and inhibition of inflammation. Therefore, sericin protein could be developed into a novel functional health food with significantly hypoglycaemic effect.

Gynura divaricata ameliorates hepatic insulin resistance by modulating insulin signalling, maintaining glycolipid homeostasis and reducing inflammation in type 2 diabetic mice.

Diabetes mellitus, one of the fastest growing epidemics worldwide, has become a serious health problem in modern society. Gynura divaricata (GD), an edible medicinal plant, has been shown to have hypoglycaemic effects. The molecular mechanisms by which GD improves hepatic insulin resistance (IR) in mice with type 2 diabetes (T2D) remain largely unknown. The aerial parts of GD were prepared in a lyophilized powder, which was added into the diet of T2D mice for 4 weeks. GD could result in an obvious decrease in fasting blood glucose and insulin levels in T2D mice. Meanwhile, the underlying mechanisms involved in the insulin-signalling pathway, glucose metabolism, lipid metabolism and inflammatory reaction in the liver tissue were also investigated by western blot, which indicated that GD further ameliorated hepatic IR by activating the PI3K/p-AKT pathway, decreasing the levels of hepatic phosphoenolpyruvate carboxykinase and glucose-6-phosphatase and increasing the levels of glucokinase and peroxisome proliferator-activated receptor-γ in the livers of T2D mice. GD has the potential to alleviate both hyperglycaemia and hepatic IR in T2D mice. Therefore, GD might be a promising functional food or medicine for T2D treatment.