Using Strontium Coated Clay Nanoparticles For Bone Regeneration And Other Biomedical Applications

The aim of this project is to coat halloysite nanotubes (HNTs) with strontium in an ecofriendly, simple, and non-expensive process. These particles, when doped in calcium phosphate cements (CPC), are predicted to increase the osteoconductive and antibacterial properties of three dimensional (3D) printed bone scaffolds. The purpose of the 3D printed bone scaffolds is to assume the same function as the bones they are replacing but with several additional functionalities. These biomaterials will have the ability to be resorbed as new bone is formed. Due to inherent osteogenic factors and antibiotics released from doped HNTs during the reparative process, it will also provide surgeons with a multi-functional construct for a diverse set of dental and orthopedic applications. The purpose of the 3D printed scaffolds will be to provide a microenvironment for normal cells along with the ability to release antimicrobial, chemotherapeutics or other drugs. The system will also enable growth factor release. Material characterization was conducted to confirm the presence of Sr on the HNTs. Cellular characterizations studies assessed cellular impact and behavior and included cytocompatibility studies, osteogenic/osteoinductive, and differentiation effects on pre-osteoblast cells and stromal cells. Material characterization studies included material strength test of the SrHNT/CPC composites. Based on the results, fabrication methods in future will be modified as needed to obtain the ideal medical construct

The Strontium-Coated Clay Nanoparticles in Calcium Phosphate Cement for Biomedical Applications

Anusha Elumalai, Yangyang Luo, and Ahmed Humayun are graduate students in Molecular Science and Nanotechnology at Louisiana Tech University. Dr. David K. Mills is a professor in the School of Biological Sciences at Louisiana Tech University. The abstract for The Strontium-Coated Clay Nanoparticles in Calcium Phosphate Cement for Biomedical Applications can be downloaded by clicking on the blue download button

Creating Structured Hydrogel Microenvironments for Regulating Stem Cell Differentiation

The development of distinct biomimetic microenvironments for regulating stem cell behavior and bioengineering human tissues and disease models requires a solid understanding of cell–substrate interactions, adhesion, and its role in directing cell behavior, and other physico-chemical cues that drive cell behavior. In the past decade, innovative developments in chemistry, materials science, microfabrication, and associated technologies have given us the ability to manipulate the stem cell microenvironment with greater precision and, further, to monitor effector impacts on stem cells, both spatially and temporally. The influence of biomaterials and the 3D microenvironment’s physical and biochemical properties on mesenchymal stem cell proliferation, differentiation, and matrix production are the focus of this review chapter. Mechanisms and materials, principally hydrogel and hydrogel composites for bone and cartilage repair that create “cell-supportive” and “instructive” biomaterials, are emphasized. We begin by providing an overview of stem cells, their unique properties, and their challenges in regenerative medicine. An overview of current fabrication strategies for creating instructive substrates is then reviewed with a focused discussion of selected fabrication methods with an emphasis on bioprinting as a critical tool in creating novel stem cell-based biomaterials. We conclude with a critical assessment of the current state of the field and offer our view on the promises and potential pitfalls of the approaches discussed

An Eco-Friendly, Simple, and Inexpensive Method for Metal-Coating Strontium onto Halloysite Nanotubes

Osteoporosis increases the risk of bone fracture by reducing bone mass and thereby increasing bone fragility. The addition of strontium (Sr) nanoparticles in bone tissue results in a strengthening of the bone, induction bone formation by osteoblasts, and reduction of bone reabsorption by osteoclasts. The use of Sr for bone tissue regeneration has gained significant research interest in recent years due to its beneficial properties in treating osteoporotic-induced bone loss. We hypothesized that Sr-coated and antibiotic-doped HNTs could be used in antimicrobial coatings and as an antibacterial drug delivery vehicle. Accordingly, we coated HNTs with strontium carbonate (SrHNT) using a simple, novel, and effective electrodeposition method. We tested the antibacterial properties of SrHNT on Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermis using the disc diffusion method. We assessed the potential cytotoxic and proliferative effects of SrHNTs on pre-osteoblasts using a Live/Dead cytotoxicity and cell proliferation assay. We successfully coated HNTs with strontium using a one-step benign coating method that does not produce any toxic waste, unlike most HNT metal-coating methods. Antibacterial tests showed that the SrHNTs had a pronounced growth inhibition effect, and cell culture studies using MC 3T3 cells concluded that SrHNTs are cytocompatible and enhance cell proliferation

An Eco-Friendly, Simple, and Inexpensive Method for Metal-Coating Strontium onto Halloysite Nanotubes

Osteoporosis increases the risk of bone fracture by reducing bone mass and thereby increasing bone fragility. The addition of strontium (Sr) nanoparticles in bone tissue results in a strengthening of the bone, induction bone formation by osteoblasts, and reduction of bone reabsorption by osteoclasts. The use of Sr for bone tissue regeneration has gained significant research interest in recent years due to its beneficial properties in treating osteoporotic-induced bone loss. We hypothesized that Sr-coated and antibiotic-doped HNTs could be used in antimicrobial coatings and as an antibacterial drug delivery vehicle. Accordingly, we coated HNTs with strontium carbonate (SrHNT) using a simple, novel, and effective electrodeposition method. We tested the antibacterial properties of SrHNT on Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermis using the disc diffusion method. We assessed the potential cytotoxic and proliferative effects of SrHNTs on pre-osteoblasts using a Live/Dead cytotoxicity and cell proliferation assay. We successfully coated HNTs with strontium using a one-step benign coating method that does not produce any toxic waste, unlike most HNT metal-coating methods. Antibacterial tests showed that the SrHNTs had a pronounced growth inhibition effect, and cell culture studies using MC 3T3 cells concluded that SrHNTs are cytocompatible and enhance cell proliferation

Effectiveness and Applications of a Metal-Coated HNT/Polylactic Acid Antimicrobial Filtration System

A broad-spectrum antimicrobial respiration apparatus designed to fight bacteria, viruses, fungi, and other biological agents is critical in halting the current pandemic’s trajectory and containing future outbreaks. We applied a simple and effective electrodeposition method for metal (copper, silver, and zinc) coating the surface of halloysite nanotubes (HNTs). These nanoparticles are known to possess potent antiviral and antimicrobial properties. Metal-coated HNTs (mHNTs) were then added to polylactic acid (PLA) and extruded to form an mHNT/PLA 3D composite printer filament. Our composite 3D printer filament was then used to fabricate an N95-style mask with an interchangeable/replaceable filter with surfaces designed to inactivate a virus and kill bacteria on contact, thus reducing deadly infections. The filter, made of a multilayered antimicrobial/mHNT blow spun polymer and fabric, is disposable, while the mask can be sanitized and reused. We used several in vitro means of assessing critical clinical features and assessed the bacterial growth inhibition against commonly encountered bacterial strains. These tests demonstrated the capability of our antimicrobial filament to fabricate N95 masks and filters that possessed antibacterial capabilities against both Gram-negative and Gram-positive bacteria