Polylactic acid (PLA) is the most commonly used biodegradable polymer in clinical applications today. Examples range from drug delivery systems, tissue engineering, temporary and long-term implantable devices; constantly expanding to new fields. This is owed greatly to the polymer's favorable biocompatibility and to its safe degradation products. Once coming in contact with biological media, the polymer begins breaking down, usually by hydrolysis, into lactic acid (LA) or to carbon dioxide and water. These products are metabolized intracellularly or excreted in the urine and breath. Bacterial infection and foreign-body inflammation enhance the breakdown of PLA, through the secretion of enzymes that degrade the polymeric matrix. The biodegradation occurs both on the surface of the polymeric device and inside the polymer body, by diffusion of water between the polymer chains. The median half-life of the polymer is 30 weeks; however, this can be lengthened or shortened to address the clinical needs. Degradation kinetics can be tuned by determining the molecular composition and the physical architecture of the device. Using L-or D-chirality of the LA will greatly slow or lengthen the degradation rates, respectively. Despite the fact that this polymer is more than 150 years old, PLA remains a fertile platform for biomedical innovation and fundamental understanding of how artificial polymers can safely coexist with biological systems.

Protocells, artificial cell-like particles, capable of autonomously synthesizing RNA and proteins based on a DNA template, are emerging platforms for studying cellular functions and for revealing the origins-of-life. Here, we show for the first time that artificial lipid-based vesicles, containing the molecular machinery necessary for transcription and translation, can be used to synthesize anti-cancer proteins inside tumors. The particles were engineered as stand-alone systems, sourcing nutrients from their biological microenvironment to trigger protein synthesis. When pre-loaded with template DNA, amino acids and energy-supplying molecules protocells synthesized, up to 2×107 copies of superfolder green fluorescent protein (sfGFP) were synthesized in each liposome. A variety of proteins, having molecular weights reaching 66 kDa and with diagnostic and therapeutic activities, were synthesized inside the particles. Incubating protein producing particles, encoded to secrete Pseudomonas exotoxin A (PE) with 4T1 breast cancer cells in culture, resulted in killing of most of the malignant cells. In mice bearing 4T1 tumors, histological evaluation of the tumor tissue after a local injection of PE-producing particles, indicating robust apoptosis. Protein producing particles are synthetic-biology platforms capable of synthesizing therapeutic proteins on-demand.

Cell-free protein synthesis (CFPS) systems are important laboratory tools that are used for various synthetic biology applications. Here, we present a simple and inexpensive laboratory-scale method for preparing a CFPS system from E. coli. The procedure uses basic lab equipment, a minimal set of reagents, and requires less than one hour to process the bacterial cell mass into a functional S30-T7 extract. BL21(DE3) and MRE600 E. coli strains were used to prepare the S30-T7 extract. The CFPS system was used to produce a set of fluorescent and therapeutic proteins of different molecular weights (up to 66 kDa). This system was able to produce 40–150 μg-protein/ml, with variations depending on the plasmid type, expressed protein and E. coli strain. Interestingly, the BL21-based CFPS exhibited stability and increased activity at 40 and 45°C. To the best of our knowledge, this is the most rapid and affordable lab-scale protocol for preparing a cell-free protein synthesis system, with high thermal stability and efficacy in producing therapeutic proteins.

Progress in bottom-up synthetic biology has stimulated the development of synthetic cells (SCs), autonomous protein-manufacturing particles, as dynamic biomimetics for replacing diseased natural cells and addressing medical needs. Here, we report that SCs genetically encoded to produce proangiogenic factors triggered the physiological process of neovascularization in mice. The SCs were constructed of giant lipid vesicles and were optimized to facilitate enhanced protein production. When introduced with the appropriate genetic code, the SCs synthesized a recombinant human basic fibroblast growth factor (bFGF), reaching expression levels of up to 9⋅10 6 protein copies per SC. In culture, the SCs induced endothelial cell proliferation, migration, tube formation, and angiogenesis-related intracellular signaling, confirming their proangiogenic activity. Integrating the SCs with bioengineered constructs bearing endothelial cells promoted the remodeling of mature vascular networks, supported by a collagen-IV basement membrane–like matrix. In vivo, prolonged local administration of the SCs in mice triggered the infiltration of blood vessels into implanted Matrigel plugs without recorded systemic immunogenicity. These findings emphasize the potential of SCs as therapeutic platforms for activating physiological processes by autonomously producing biological drugs inside the body.

Targeting neurons in breast cancer with anesthetic nanoparticles inhibits nerve-cancer stimulation and tumor progression.