DNA scaffolds enable efficient and tunable functionalization of biomaterials for immune cell modulation.
Ontology highlight
ABSTRACT:
SUBMITTER: Huang X
PROVIDER: S-EPMC7878327 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Elastomeric, fully degradable and biocompatible biomaterials are rare, with current options presenting significant limitations in terms of ease of functionalization and tunable mechanical and degradation properties. We report a new method for covalently crosslinking tyrosine residues in silk proteins, via horseradish peroxidase and hydrogen peroxide, to generate highly elastic hydrogels with tunable properties. The tunable mechanical properties, gelation kinetics and swelling properties of these new protein polymers, in addition to their ability to withstand shear strains on the order of 100%, compressive strains greater than 70% and display stiffness between 200 - 10,000 Pa, covering a significant portion of the properties of native soft tissues. Molecular weight and solvent composition allowed control of material mechanical properties over several orders of magnitude while maintaining high resilience and resistance to fatigue. Encapsulation of human bone marrow derived mesenchymal stem cells (hMSC) showed long term survival and exhibited cell-matrix interactions reflective of both silk concentration and gelation conditions. Further biocompatibility of these materials were demonstrated with in vivo evaluation. These new protein-based elastomeric and degradable hydrogels represent an exciting new biomaterials option, with a unique combination of properties, for tissue engineering and regenerative medicine.
| S-EPMC4225629 | biostudies-literature
Project description:siRNA and microRNA are promising therapeutic agents, which are engaged in a natural mechanism called RNA interference that modulates gene expression posttranscriptionally. For intracellular delivery of such nucleic acid triggers, we use sequence-defined cationic polymers manufactured through solid phase chemistry. They consist of an oligoethanamino amide core for siRNA complexation and optional domains for nanoparticle shielding and cell targeting. Due to the small size of siRNA, electrostatic complexes with polycations are less stable, and consequently intracellular delivery is less efficient. Here we use DNA oligomers as adaptors to increase size and charge of cargo siRNA, resulting in increased polyplex stability, which in turn boosts transfection efficiency. Extending a single siRNA with a 181-nucleotide DNA adaptor is sufficient to provide maximum gene silencing aided by cationic polymers. Interestingly, this simple strategy was far more effective than merging defined numbers (4-10) of siRNA units into one DNA scaffolded construct. For DNA attachment, the 3' end of the siRNA passenger strand was beneficial over the 5' end. The impact of the attachment site however was resolved by introducing bioreducible disulfides at the connection point. We also show that DNA adaptors provide the opportunity to readily link additional functional domains to siRNA. Exemplified by the covalent conjugation of the endosomolytic influenza peptide INF-7 to siRNA via a DNA backbone strand and complexing this construct with a targeting polymer, we could form a highly functional polyethylene glycol-shielded polyplex to downregulate a luciferase gene in folate receptor-positive cells.
| S-EPMC5014462 | biostudies-other
Project description:The precise mechanisms that lead to orthopedic implant failure are not well understood; it is believed that the micromechanical environment at the bone-implant interface regulates structural stability of an implant. In this work, we seek to understand how the 3D mechanical environment of an implant affects bone formation during early osteointegration. We employed two-photon lithography (TPL) direct laser writing to fabricate 3-dimensional rigid polymer scaffolds with tetrakaidecahedral periodic geometry, herewith referred to as nanolattices, whose strut dimensions were on the same order as osteoblasts' focal adhesions (?2?m) and pore sizes on the order of cell size, ?10?m. Some of these nanolattices were subsequently coated with thin conformal layers of Ti or W, and a final outer layer of 18nm-thick TiO2 was deposited on all samples to ensure biocompatibility. Nanomechanical experiments on each type of nanolattice revealed the range of stiffnesses of 0.7-100MPa. Osteoblast-like cells (SAOS-2) were seeded on each nanolattice, and their mechanosensitve response was explored by tracking mineral secretions and intracellular f-actin and vinculin concentrations after 2, 8 and 12days of cell culture in mineralization media. Experiments revealed that the most compliant nanolattices had ?20% more intracellular f-actin and ?40% more Ca and P secreted onto them than the stiffer nanolattices, where such cellular response was virtually indistinguishable. We constructed a simple phenomenological model that appears to capture the observed relation between scaffold stiffness and f-actin concentration. This model predicts a range of optimal scaffold stiffnesses for maximum f-actin concentration, which appears to be directly correlated with osteoblast-driven mineral deposition. This work suggests that three-dimensional scaffolds with titania-coated surfaces may provide an optimal microenvironment for cell growth when their stiffness is similar to that of cartilage (?0.5-3MPa). These findings help provide a greater understanding of osteoblast mechanosensitivity and may have profound implications in developing more effective and safer bone prostheses. STATEMENT OF SIGNIFICANCE:Creating prostheses that lead to optimal bone remodeling has been a challenge for more than two decades because of a lack of thorough knowledge of cell behavior in three-dimensional (3D) environments. Literature has shown that 2D substrate stiffness plays a significant role in determining cell behavior, however, limitations in fabrication techniques and difficulties in characterizing cell-scaffold interactions have limited our understanding of how 3D scaffolds' stiffness affects cell response. The present study shows that scaffold structural stiffness affects osteoblasts cellular response. Specifically this work shows that the cells grown on the most compliant nanolattices with a stiffness of 0.7MPa expressed ?20% higher concentration of intracellular f-actin and secreted ?40% more Ca and P compared with all other nanolattices. This suggests that bone scaffolds with a stiffness close to that of cartilage may serve as optimal 3D scaffolds for new synthetic bone graft materials.
| S-EPMC5663471 | biostudies-literature
Project description:Bombyx mori silk fibroin is a promising biomaterial for tissue regeneration and is usually considered an "inert" material with respect to actively regulating cell differentiation due to few specific cell signaling peptide domains in the primary sequence and the generally stiffer mechanical properties due to crystalline content formed in processing. In the present study, silk fibroin porous 3D scaffolds with nanostructures and tunable stiffness were generated via a silk fibroin nanofiber-assisted lyophilization process. The silk fibroin nanofibers with high ?-sheet content were added into the silk fibroin solutions to modulate the self-assembly, and to directly induce water-insoluble scaffold formation after lyophilization. Unlike previously reported silk fibroin scaffold formation processes, these new scaffolds had lower overall ?-sheet content and softer mechanical properties for improved cell compatibility. The scaffold stiffness could be further tuned to match soft tissue mechanical properties, which resulted in different differentiation outcomes with rat bone marrow-derived mesenchymal stem cells toward myogenic and endothelial cells, respectively. Therefore, these silk fibroin scaffolds regulate cell differentiation outcomes due to their mechanical features.
| S-EPMC4428940 | biostudies-literature
Project description:Scaffolded DNA origami enables the fabrication of a variety of complex nanostructures that promise utility in diverse fields of application, ranging from biosensing over advanced therapeutics to metamaterials. The broad applicability of DNA origami as a material beyond the level of proof-of-concept studies critically depends, among other factors, on the availability of large amounts of pure single-stranded scaffold DNA. Here, we present a method for the efficient production of M13 bacteriophage-derived genomic DNA using high-cell-density fermentation of Escherichia coli in stirred-tank bioreactors. We achieve phage titers of up to 1.6 × 10(14) plaque-forming units per mL. Downstream processing yields up to 410 mg of high-quality single-stranded DNA per one liter reaction volume, thus upgrading DNA origami-based nanotechnology from the milligram to the gram scale.
| S-EPMC4532261 | biostudies-literature
Project description:Engineering the microbial transformation of lignocellulosic biomass is essential to developing modern biorefining processes that alleviate reliance on petroleum-derived energy and chemicals. Many current bioprocess streams depend on the genetic tractability of Escherichia coli with a primary emphasis on engineering cellulose/hemicellulose catabolism, small molecule production, and resistance to product inhibition. Conversely, bioprocess streams for lignin transformation remain embryonic, with relatively few environmental strains or enzymes implicated. Here we develop a biosensor responsive to monoaromatic lignin transformation products compatible with functional screening in E. coli. We use this biosensor to retrieve metagenomic scaffolds sourced from coal bed bacterial communities conferring an array of lignin transformation phenotypes that synergize in combination. Transposon mutagenesis and comparative sequence analysis of active clones identified genes encoding six functional classes mediating lignin transformation phenotypes that appear to be rearrayed in nature via horizontal gene transfer. Lignin transformation activity was then demonstrated for one of the predicted gene products encoding a multicopper oxidase to validate the screen. These results illuminate cellular and community-wide networks acting on aromatic polymers and expand the toolkit for engineering recombinant lignin transformation based on ecological design principles.
| S-EPMC4104913 | biostudies-literature
Project description:Applying synthetic biology to engineer gut-resident microbes provides new avenues to investigate microbe-host interactions, perform diagnostics, and deliver therapeutics. Here, we describe a platform for engineering Bacteroides, the most abundant genus in the Western microbiota, which includes a process for high-throughput strain modification. We have identified a novel phage promoter and translational tuning strategy and achieved an unprecedented level of expression that enables imaging of fluorescent-protein-expressing Bacteroides stably colonizing the mouse gut. A detailed characterization of the phage promoter has provided a set of constitutive promoters that span over four logs of strength without detectable fitness burden within the gut over 14 days. These promoters function predictably over a 1,000,000-fold expression range in phylogenetically diverse Bacteroides species. With these promoters, unique fluorescent signatures were encoded to allow differentiation of six species within the gut. Fluorescent protein-based differentiation of isogenic strains revealed that priority of gut colonization determines colonic crypt occupancy.
| S-EPMC5576361 | biostudies-literature
Project description:The number of methodologies for the immobilization of enzymes using polymeric supports is continuously growing due to the developments in the fields of biotechnology, polymer chemistry, and nanotechnology in the last years. Despite being excellent catalysts, enzymes are very sensitive molecules and can undergo denaturation beyond their natural environment. For overcoming this issue, polymer chemistry offers a wealth of opportunities for the successful combination of enzymes with versatile natural or synthetic polymers. The fabrication of functional, stable, and robust biocatalytic hybrid materials (nanoparticles, capsules, hydrogels, or films) has been proven advantageous for several applications such as biomedicine, organic synthesis, biosensing, and bioremediation. In this review, supported with recent examples of enzyme-protein hybrids, we provide an overview of the methods used to combine both macromolecules, as well as the future directions and the main challenges that are currently being tackled in this field.
| S-EPMC7406678 | biostudies-literature
Project description:The cell microenvironment plays a pivotal role in mediating cell adhesion, survival, and proliferation in physiological and pathological states. The relevance of extracellular matrix (ECM) proteins in cell fate control is an important issue to take into consideration for both tissue engineering and cell biology studies. The glycosylation of ECM proteins remains, however, largely unexplored. In order to investigate the physio-pathological effects of differential ECM glycosylation, the design of affordable chemoselective methods for ECM components glycosylation is desirable. We will describe a new chemoselective glycosylation approach exploitable in aqueous media and on non-protected substrates, allowing rapid access to glyco-functionalized biomaterials.
| S-EPMC6480084 | biostudies-literature
Project description:Various congenital and acquired urinary system abnormalities can cause structural damage to patients' bladders. This study aimed to construct and evaluate a novel surgical patch encapsulated with adipose-derived stem cells (ADSCs) for bladder tissue regeneration. The surgical patch consists of multiple biomaterials, including bladder acellular matrix (BAM), collagen type I from rat tail, microparticle emulsion cross-linking polylactic-co-glycolic acid (PLGA)-chitosan (CS) with PLGA-sodium alginate (SA), and growth factors. ADSCs were seeded on the surgical patch. Approximately 50% of the bladder was excised and replaced with a surgical patch. Histological, immunohistochemical and urodynamic analyses were performed at the 2nd, 4th, and 8th weeks after surgery, respectively. The PLGA-CS, PLGA-SA or surgical patch showed no cytotoxicity to ADSCs. PLGA-CS cross-linked with PLGA-SA at a ratio of 5:5 exhibited a loose microporous structure and was chosen as the candidate for ADSC seeding. We conducted bladder repair surgery in rats using the patch, successfully presenting urothelium layers, muscle bundles, and vessel regeneration and replacing 50% of the rat's natural bladder in vivo. Experiments through qualitative and quantitative evaluation demonstrate the application potential of the composite biomaterials in promoting the repair and reconstruction of bladder tissue.
| S-EPMC9269300 | biostudies-literature