This paper presents the generation and evaluation of a novel potential drug delivery platform for biologics, based on recombinant spider silk. Targeting CD40 for activation of antigen presenting cells, in order to overcome tumor induced T cell tolerance, have shown promising results in cell and animal models. However, further trials have gained limited results due to severe side reactions. To overcome this, we have investigated a strategy for a localized CD40 activation. A CD40 agonist based on a single chain variable fragment (scFv<inf>CD40</inf>) was enzymatically coupled to silk structures, that were then used to stimulate cells in vitro. A reporter cell line responsive to CD40 agonists was used to evaluate the bioactivity of the developed scFv<inf>CD40</inf>-silk, and to optimize the method. Once the bioactivity was confirmed, human primary B cells derived from healthy donors were stimulated with the scFv<inf>CD40</inf>-silk construct. The resulting B cell response was characterized both by upregulated surface expression of the activation marker CD86 (3 fold), suggesting an improved antigen-presenting capacity, and by B cell proliferation (4 fold) generating an expanded B cell population. The detected upregulation of the costimulatory molecule CD86 on the B cells implies a potential of the functionalized silk to steer the tumor-specific T cell response from tolerance to immune activation, including the onset of appropriate effector functions. Finally, we investigated the usability of the novel silk format microspheres for CD40-mediated cell activation in vitro. Here, we were able to demonstrate that scFv<inf>CD40</inf>-coupled silk microspheres gave a pronounced activation of the CD40-expressing reporter cell line, supporting the suitability of silk microspheres for the delivery of biologics with immune modulatory purposes.

Elongated protein‐based micro‐ and nanostructures are of great interest for a wide range of biomedical applications, where they can serve as a backbone for surface functionalization and as vehicles for drug delivery. Current production methods for protein constructs lack precise control of either shape and dimensions or render structures fixed to substrates. This work demonstrates production of recombinant spider silk nanowires suspended in solution, starting with liquid bridge induced assembly (LBIA) on a substrate, followed by release using ultrasonication, and concentration by centrifugation. The significance of this method lies in that it provides i) reproducability (standard deviation of length <13% and of diameter <38%), ii) scalability of fabrication, iii) compatibility with autoclavation with retained shape and function, iv) retention of bioactivity, and v) easy functionalization both pre‐ and post‐formation. This work demonstrates how altering the function and nanotopography of a surface by nanowire coating supports the attachment and growth of human mesenchymal stem cells (hMSCs). Cell compatibility is further studied through integration of nanowires during aggregate formation of hMSCs and the breast cancer cell line MCF7. The herein‐presented industrial‐compatible process enables silk nanowires for use as functionalizing agents in a variety of cell culture applications and medical research.

In this work we present three different ways to characterize the mechanical properties of spider silk nanomembranes. The nanomembranes are formed by self-assembly at the liquid:air interface of a standing solution from which they can be lifted. The mechanical properties are evaluated by (1) manually dropping lead bullets onto the nanomembrane, (2) motorized lowering of a cylindrical indenter to record force-deformation characteristics, and (3) using a standard bulging experiments. Using these methods we show that the nanomembranes are both strong and flexible opening up for applications as pneumatic actuators in MEMS microvalves, or as cell layer actuators in organ-on-a-chip. 

The composition of serum proteins is reflecting the current health status and can, with the right tools, be used to detect early signs of disease, such as an emerging cancer. An earlier diagnosis of cancer would greatly increase the chance of an improved outcome for the patients. However, there is still an unmet need for proficient tools to decipher the information in the blood proteome, which calls for further technological development. Here, we present a proof-of-concept study that demonstrates an alternative approach for multiplexed protein profiling of serum samples in solution, using DNA barcoded scFv antibody fragments and next generation sequencing. The outcome shows high accuracy when discriminating samples derived from pancreatic cancer patients and healthy controls and represents a scalable alternative for serum analysis. Brofelth, Ekstrand et al use DNA barcoded scFv antibody fragments and next generation sequencing for multiplex profiling of proteins in serum from pancreatic cancer patients with high accuracy. This approach can potentially be used in high throughput precision diagnosis.

Biologically compatible membranes are of high interest for several biological and medical applications. Tissue engineering, for example, would greatly benefit from ultrathin, yet easy‐to‐handle, biodegradable membranes that are permeable to proteins and support cell growth. In this work, nanomembranes are formed by self‐assembly of a recombinant spider silk protein into a nanofibrillar network at the interface of a standing aqueous solution. The membranes are cm‐sized, free‐standing, bioactive and as thin as 250 nm. Despite their nanoscale thickness, the membranes feature an ultimate engineering strain of over 220% and a toughness of 5.2 MPa. Moreover, they are permeable to human blood plasma proteins and promote cell adherence and proliferation. Human keratinocytes seeded on either side of the membrane form a confluent monolayer within three days. The significance of these results lays in the unique combination of nanoscale thickness, elasticity, toughness, biodegradability, protein permeability and support for cell growth, as this may enable new applications in tissue engineering including bi‐layered in vitro tissue models and support for clinical transplantation of coherent cell layers.

A method for manufacturing shaped polymers of surface-active macromolecules, in particular silk, is provided. The method is comprising the steps of: • a) depositing an aqueous solution of the surface-active macromolecules on a surface, wherein the aqueous solution of the surface-active macromolecules is deposited in the form of a droplet, and wherein the surface is a hydrophobic micropatterned surface adapted to prevent the aqueous solution from penetrating into the pattern and to receive the droplet of the aqueous solution of the surface-active macromolecules and retain its droplet state; and • b) forming shaped polymers of the surface-active macromolecules on the surface.   

This paper reports on the first formation of a thin bio-functionalized spider silk tube, supported by an internal micromachined scaffold, in which both the inside and outside of the tube wall are freely accessible. The silk tube could potentially be used as an artificial blood vessel in an in vitro tissue scaffold, where endothelial cells and tissue cells can grow on both sides of the silk tube.

Mucoadhesion is defined as the adhesion of a material to the mucus gel covering the mucous membranes. The mechanisms controlling mucoadhesion include nonspecific electrostatic interactions and specific interactions between the materials and the mucins, the heavily glycosylated proteins that form the mucus gel. Mucoadhesive materials can be used to develop mucosal wound dressings and noninvasive transmucosal drug delivery systems. Spider silk, which is strong, biocompatible, biodegradable, nontoxic, and lightweight would serve as an excellent base for the development of such materials. Here, we investigated two variants of the partial spider silk protein 4RepCT genetically engineered in order to functionalize them with mucoadhesive properties. The pLys-4RepCT variant was functionalized with six cationically charged lysines, aiming to provide nonspecific adhesion from electrostatic interactions with the anionically charged mucins, while the hGal3-4RepCT variant was genetically fused with the Human Galectin-3 Carbohydrate Recognition Domain which specifically binds the mucin glycans Gal beta 1-3GlcNAc and Gal beta 1-4GlcNAc. First, we demonstrated that coatings, fibers, meshes, and foams can be readily made from both silk variants. Measured by the adsorption of both bovine submaxillary mucin and pig gastric mucin, the newly produced silk materials showed enhanced mucin binding properties compared with materials of wild-type (4RepCT) silk. Moreover, we showed that pLys-4RepCT silk coatings bind mucins through electrostatic interactions, while hGal3-4RepCT silk coatings bind mucins through specific glycan-protein interactions. We envision that the two new mucoadhesive silk variants pLys-4RepCT and hGal3-4RepCT, alone or combined with other biofunctional silk proteins, constitute useful new building blocks for a range of silk protein-based materials for mucosal treatments.