Toward Bioactive Hydrogels: A Tunable Approach via Nucleic Acid-Collagen Complexation.

Purpose: Nucleic acid-collagen complexes (NACCs) are unique biomaterials formed by binding short, monodisperse single-stranded DNA (ssDNA) with type I collagen. These complexes spontaneously generate microfibers and nanoparticles of varying sizes, offering a versatile platform with potential applications in tissue engineering and regenerative medicine. However, the detailed mechanisms behind the nucleic acid-driven assembly of collagen fibers still need to be established.

Multifunctional DNA-Collagen Biomaterials: Developmental Advances and Biomedical Applications.

The complexation of nucleic acids and collagen forms a platform biomaterial greater than the sum of its parts. This union of biomacromolecules merges the extracellular matrix functionality of collagen with the designable bioactivity of nucleic acids, enabling advances in regenerative medicine, tissue engineering, gene delivery, and targeted therapy. This review traces the historical foundations and critical applications of DNA-collagen complexes and highlights their capabilities, demonstrating them as biocompatible, bioactive, and tunable platform materials.

Exploring the Fibrous Nature of Single-Stranded DNA-Collagen Complexes: Nanostructural Observations and Physicochemical Insights.

Nucleic acid-collagen complexes (NACCs) are a self-assembled biomimetic fibrillary platform arising from the spontaneous complexation of single-stranded DNA (ssDNA) oligonucleotides and collagen. NACCs merge the extracellular matrix functionality of collagen with the tunable bioactivity of ssDNA as aptamers for broad biomedical applications. We hypothesize that NACCs offer a hierarchical architecture across multiple length scales that significantly varies compared to native collagen.

The Effects of Simulated and Real Microgravity on Vascular Smooth Muscle Cells.

As considerations are being made for the limitations and safety of long-term human spaceflight, the vasculature is important given its connection to and impact on numerous organ systems. As a major constituent of blood vessels, vascular smooth muscle cells are of interest due to their influence over vascular tone and function. Additionally, vascular smooth muscle cells are responsive to pressure and flow changes.

Spaceflight effects on human vascular smooth muscle cell phenotype and function.

The cardiovascular system is strongly impacted by the hazards of spaceflight. Astronauts spending steadily increasing lengths of time in microgravity are subject to cardiovascular deconditioning resulting in loss of vascular tone, reduced total blood volume, and diminished cardiac output. Appreciating the mechanisms by which the cells of the vasculature are altered during spaceflight will be integral to understanding and combating these deleterious effects as the human presence in space advances.

Sex as a Biological Variable in Tissue Engineering and Regenerative Medicine.

Although sex differences have been noted in cellular function and behavior, therapy efficacy, and disease incidence and outcomes, the adoption of sex as a biological variable in tissue engineering and regenerative medicine remains limited. Furthering the development of personalized, precision medicine requires considering biological sex at the bench and in the clinic. This review provides the basis for considering biological sex when designing tissue-engineered constructs and regenerative therapies by contextualizing sex as a biological variable within the tissue engineering triad of cells, matrices, and signals.

Hemocompatibility of all-trans retinoic acid-loaded citrate polymer coatings for vascular stents.

Purpose: Current strategies implementing drug-eluting polymer stent coatings fail to fully address the lasting effects of endothelial suppression which ultimately result in delayed reendothelialization and thrombogenic complications. The present study investigates the hemocompatibility of all-trans retinoic acid loaded poly (1,8-octanediol-co-citrate) coatings (AtRA-POC coatings) for advanced intravascular stent technology. The ability of these materials in supporting endothelial restoration via migration and proliferation while inhibiting smooth muscle cell growth is also explored.

Ancestry of cells must be considered in bioengineering.

Bioengineered platforms, intended to be used in the investigation of human health and disease, often incorporate cells of unknown ancestry or that lack diversity. To develop tools and platforms that benefit the entire human population, we must consider the ancestry of cells and intentionally diversify the cells we use in our designs.

Ancestral Background Is Underreported in Regenerative Engineering.

Purpose: The ancestral background of human cells may play a role in cells' behavior and response to therapeutic interventions in vitro. We investigate the prevalence of ancestry reporting in current biological research and suggest that increased reporting would be beneficial to the field.

Methods: Articles published over a six-month period in ten different journals were reviewed for their use of human primary cells and immortalized cell lines, and were analyzed based on whether or not the ancestral or ethnic information of cell donors was ascertainable.

Engineering Vascular Grafts with Multiphase Structures.

Blood vessels in the body are multiphasic organs with microenvironmental niches specific to the cells that inhabit each section. Electrospinning is a fabrication technique used to produce nano- to microfibrous architectures capable of mimicking native extracellular matrix structure. Likewise, polycitrate elastomers are favorable luminal materials for vascular applications because of their hemocompatibility and mechanical properties.

The Effects of Simulated Microgravity on Macrophage Phenotype.

The effects of spaceflight, including prolonged exposure to microgravity, can have significant effects on the immune system and human health. Altered immune cell function can lead to adverse health events, though precisely how and to what extent a microgravity environment impacts these cells remains uncertain. Macrophages, a key immune cell, effect the inflammatory response as well as tissue remodeling and repair.

Sex-Specific Response to Combinations of Shear Stress and Substrate Stiffness by Endothelial Cells In Vitro.

By using a full factorial design of experiment, the combinatorial effects of biological sex, shear stress, and substrate stiffness on human umbilical vein endothelial cell (HUVEC) spreading and Yes-associated protein 1 (YAP1) activity are able to be efficiently evaluated. Within the range of shear stress (0.5-1.

Macrophages in microgravity: the impact of space on immune cells.

The effects of a microgravity environment on the myriad types of immune cells present within the human body have been assessed both by bench-scale simulation and suborbital methods, as well as in true spaceflight. Macrophages have garnered increased research interest in this context in recent years. Their functionality in both immune response and tissue remodeling makes them a unique cell to investigate in regards to gravisensitive effects as well as parameters of interest that could impact astronaut health.

Self-assembled VEGF-R2 targeting DNA aptamer-collagen fibers stimulate an angiogenic-like endothelial cell phenotype.

Vascularization of engineered tissue is one of the hallmark challenges of tissue engineering. Leveraging self-assembled nucleic acid-collagen complexes (NACCs), we mixed a VEGF-R2 targeting aptamer or its receptor agonist divalent assembly with type I collagen to assemble NACC microfibers. Human umbilical vein endothelial cells (HUVECs) quickly remodeled these fibers into tubulogenic-like structures over 48 h.

Fund Black scientists.

Our nationwide network of BME women faculty collectively argue that racial funding disparity by the National Institutes of Health (NIH) remains the most insidious barrier to success of Black faculty in our profession. We thus refocus attention on this critical barrier and suggest solutions on how it can be dismantled.

Oligomer Length Defines the Self-Assembly of Single-Stranded DNA-Collagen Complex Fibers.

Collagen and single-stranded DNA (ssDNA) complex to self-assemble into fibers depending on the length of the ssDNA and the relative amounts of collagen and ssDNA in solution. We report for the first time that when monodisperse, random sequences of ssDNA in the range of 15-90 nucleotides and type I collagen were mixed together at room temperature, fibers several tens of micrometers in length and as large as 10 μm in diameter were formed. Fiber formation was rapid and spontaneous, requiring no further treatment after mixing.

Anti-VEGF-R2 Aptamer and RGD Peptide Synergize in a Bifunctional Hydrogel for Enhanced Angiogenic Potential.

Hydrogels have gained interest for use in tissue regeneration and wound healing because of their absorbing and swelling properties as well as their ability to mimic the natural extracellular matrix. Their use in wound healing specifically may be in the form of a patch or wound dressing or they may be administered within the wound bed as a filler, gel in situ, to promote healing. Thiolated hyaluronic acid-polyethylene diacrylate (tHA-PEGDA) hydrogels are ideal for this purpose due to their short gelation times at physiological temperature and pH.

Let's Talk About Sex-Biological Sex Is Underreported in Biomaterial Studies.

Precision medicine aims to better individualize healthcare. It requires that biomaterials be designed for the physiological characteristics of a specific patient. To make this a reality, biomaterials research and development must address differences of biological sex.

Mineralized DNA-collagen complex-based biomaterials for bone tissue engineering.

DNA is a highly polyanionic biomolecule that complexes with both collagen and hydroxyapatite. By combining these complexes, we synthesized nucleic-acid collagen complexes (NACC) mineralized with hydroxyapatite. The composite complexes were made using a short, monodisperse single-stranded DNA, type I collagen, and mineralizing medium.

Palm readings: Manicaria saccifera palm fibers are biocompatible textiles with low immunogenicity.

Plant-based fibers are a potential alternative to synthetic polymer fibers that can yield enhanced biocompatibility and mechanical properties matching those properties of tissue. Given the unique morphology of the bract of the Manicaria saccifera palm, being an interwoven meshwork of fibers, we believe that these fibers with this built-in structure could prove useful as a tissue engineering scaffold material. Thus, we first investigated the fiber's in vitro biocompatibility and immunogenicity.

In vitro and in vivo biocompatibility assessment of free radical scavenging nanocomposite scaffolds for bone tissue regeneration.

Bone is the second most transplanted tissue in the world, resulting in increased demand for bone grafts leading to the fabrication of synthetic scaffold grafting alternatives. Fracture sites are under increased oxidative stress after injuries, affecting osteoblast function and hindering fracture healing and remodeling. To counter oxidative stress, free radical scavenging agents, such as cerium oxide nanoparticles, have gained traction in tissue engineering.

Multi-layer approaches to scaffold-based small diameter vessel engineering: A review.

Cardiovascular disease is one of the leading causes of death in the world. A characteristic symptom of cardiovascular disease is occlusion of vessels. Once vascular occlusion occurs there is a critical need to re-establish flow to prevent ischemia in the downstream tissues.

Vascular Endothelial Cell Behavior in Complex Mechanical Microenvironments.

The vascular mechanical microenvironment consists of a mixture of spatially and temporally changing mechanical forces. This exposes vascular endothelial cells to both hemodynamic forces (fluid flow, cyclic stretching, lateral pressure) and vessel forces (basement membrane mechanical and topographical properties). The vascular mechanical microenvironment is "complex" because these forces are dynamic and interrelated.

Fabrication of a bilayer scaffold for small diameter vascular applications.

One of the greatest challenges plaguing cardiovascular tissue engineering has been the development of a compliant vascular graft. In this work, we report the development of a synthetic vascular graft with compliance similar to native arteries at physiological pressures. A bilayer scaffold was fabricated from a solid polymeric lumen made from poly(1,8 octanediol-co-citrate) (POC) and a microfibrous medial layer composed of type I collagen, elastin, and POC.

Mechanical and degradation property improvement in a biocompatible Mg-Ca-Sr alloy by thermomechanical processing.

Magnesium-based alloys have attracted interest as a potential material to comprise biomedical implants that are simultaneously high-strength and temporary, able to provide stabilization before degrading safely and able to be excreted by the human body. Many alloy systems have been evaluated, but this work reports on improved properties through hot extrusion of one promising alloy: Mg-1.0 wt% Ca-0.