Probing Protein Aggregation at Buried Interfaces: Distinguishing Adsorbed Protein Monomer, Dimer, and Monomer-Dimer Mixture in Situ

Protein adsorption on surfaces greatly impacts many applications such as biomedical materials, anti-biofouling coatings, bio-separation membranes, biosensors, and antibody protein drugs etc. For example, protein drug adsorption on widely used...

Advanced protein drugs and formulations

: For a long time, proteins were a subset of molecules rarely applied as therapeutically active molecules. Some of the first applications of proteins as drugs have been insulin and vaccines for supply a physiological deficiency and the prevention of diseases, respectively. Nowadays, proteins have increased their range of application, not only as drugs but also as drug delivery systems to be administered by different routes. Due to their nature, proteins show different behavior while the conditions of the environment are modified. For this reason, it has been necessary to study their behavior for predicting the correct manufacturing, storing, or combination with other possible molecules in a formulation or into the body. The application of techniques for predicting the behavior of proteins in different environments has led to associate this type of behavior into the body with the occurrence of diseases such as celiac disease or Alzheimer's disease. Thus, this work shows an overview of the main types of proteins applied as active therapeutically molecules, proteins-based drug delivery systems, and techniques for predicting their stability into the storing container and the body.

Intracellular delivery of protein drugs with an autonomously lysing bacterial system reduces tumor growth and metastases

Critical cancer pathways often cannot be targeted because of limited efficiency crossing cell membranes. Here we report the development of a Salmonella-based intracellular delivery system to address this challenge. We engineer genetic circuits that (1) activate the regulator flhDC to drive invasion and (2) induce lysis to release proteins into tumor cells. Released protein drugs diffuse from Salmonella containing vacuoles into the cellular cytoplasm where they interact with their therapeutic targets. Control of invasion with flhDC increases delivery over 500 times. The autonomous triggering of lysis after invasion makes the platform self-limiting and prevents drug release in healthy organs. Bacterial delivery of constitutively active caspase-3 blocks the growth of hepatocellular carcinoma and lung metastases, and increases survival in mice. This success in targeted killing of cancer cells provides critical evidence that this approach will be applicable to a wide range of protein drugs for the treatment of solid tumors.

Injectable Liposome Based Supramolecular Hydrogels for the Programmable Release of Multiple Protein Drugs

Directing and manipulating biological functions is at the heart of next-generation biomedical initiatives. However, the ambitious goal of engineering complex biological networks requires the ability to precisely perturb specific signaling pathways at distinct times and places. Biomaterials that can precisely control drug presentation are therefore critical for advancing next-generation biomedical initiatives such as tissue and immuno-engineering. Using lipid nanotechnology and the principles of supramolecular self-assembly, we set out to develop a novel injectable liposomal nanocomposite hydrogel platform to program the co-release of multiple protein drugs. This report details the mechanical properties and in vivo biocompatibility of these liposomal hydrogels, as well as their ability to simultaneously mediate orthogonal modes of protein release both in vitro and in vivo. Liposomal hydrogels broadly featured shear-thinning and self-healing behaviors enabling facile injectability for local drug delivery applications. By integrating modular lipid nanotechnology into our hydrogel platform, we introduced multiple mechanisms of protein release based on liposome surface chemistry. When injected into immuno-competent mice, liposomal hydrogels were both biodegradable and biocompatible. To fully validate the utility of this system for multi-protein delivery, we demonstrated the synchronized, sustained, and localized release of IgG antibody and IL-12 cytokine in vivo, despite the significant size differences between these two proteins. Overall, liposomal nanocomposite hydrogels are a highly modular platform technology with the potential to precisely coordinate biological cues both in vitro and in vivo.

Self-Encapsulation of Biomacromolecule Drugs in Porous Microscaffolds with Aqueous Two-Phase Systems

At present, the most commonly used methods of microencapsulation of protein drugs such as spray drying, multiple emulsification, and phase separation, can easily cause the problem of protein instability, which leads to low bioavailability and uncontrolled release of protein drugs. Herein, a novel method to encapsulate protein drugs into porous microscaffolds effectively and stably was described. Ammonium hydrogen carbonate (NH4HCO3) was employed to prepare porous microscaffolds. α-Amylase was encapsulated into the porous microscaffolds without denaturing conditions by an aqueous two-phase system (PEG/Sulfate). The pores were closed by heating above the glass transition temperature to achieve a sustained release of microscaffolds. The pore-closed microscaffolds were characterized and released in vitro. The integrity and activity of protein drugs were investigated to verify that this method was friendly to protein drugs. Results showed that the pores were successfully closed and a high loading amount of 9.67 ± 6.28% (w/w) was achieved. The pore-closed microscaffolds released more than two weeks without initial burst, and a high relative activity (92% compared with native one) of protein demonstrated the feasibility of this method for protein drug encapsulation and delivery.