#bioactive materials

Bacteria-killing glass offers hope in fight against hospital infections

Scientists at Aston University have discovered a technique similar to medieval stained glass-making that can completely eradicate the deadliest hospital infections within hours.

Using a so-called bioactive phosphate glass containing small amounts of the metallic element cobalt, the researchers were able to achieve a "complete kill" of the deadly bacterial infections E.coli and Candida albicans (a fungal infection associated with surgery), as well as a near-complete kill of Staphylococcus aureus (the drug-resistant form of which is MRSA).

Lead researcher, Dr. Richard Martin of Aston University in Birmingham, said the findings had significant implications, offering the possibility of cheap, antimicrobial implants and coatings to combat the most common sources of infections associated with medical care.

Avoiding the need for antibiotics, it is also thought the bioactive glass could be effective against drug-resistant 'superbugs,' helping to tackle the growing problem of antimicrobial resistance (AMR).

Engineering ECM-like fibers with bioactive silk for 3-D cell culture

Biological tissues are built when cells anchor to specific sites on a 3-D microfiber network in an extracellular matrix (ECM). Scientists are keen to recreate biological tissues in the lab using bioinspired tissue engineering and genetic engineering, to form functional ECM motifs fused to recombinant silk proteins. Under adequate physiological conditions, bioengineered silk proteins and fibronectin-silk (FN-silk) can self-assemble into microfiber networks that mimic native ECM.

In a recent study, Ulrika Johansson, Mona Widhe and co-workers at the interdisciplinary departments of Biotechnology, Biomaterials Chemistry, and Immunology in Sweden developed a method to include mammalian cells into a silk solution before assembling silk into constructs, to form uniform cell-integrated tissue-like microfibers. The resulting 3-D scaffold constructs showed improved cell proliferation (growth) and homogenous cell spreading compared to cells encapsulated in hydrogel. The results of the study are now published in Scientific Reports.

The scientists confirmed cell attachment on fibronectin-silk constructs (FN-Silk) in the work by observing filamentous actin and by defining focal adhesion points of the attached, elongated cells. They maintained cell viability for 90 days in the cell-FN/silk surfaces and showed scalability of the method to macro-sized 3-D cell cultures. The silk microfiber bundles with encapsulated cells maintained biomechanical strength and extendibility much like human arterial walls.

Advanced biomaterials with silk fibroin-bioactive glass to engineer patient-specific 3-D bone grafts

The complex architecture of bone is challenging to recreate in the lab. Therefore, advances in bone tissue engineering (BTE) aim to build patient-specific grafts that assist bone repair and trigger specific cell-signaling pathways. Materials scientists in regenerative medicine and BTE progressively develop new materials for active biological repair at a site of defect post-implantation to accelerate healing through bone biomimicry.

Rapidly initiation of new bone formation at the site of implantation is a highly desirable feature in BTE, and scientists are focused on fabricating grafts that strengthen the material-bone interface after implantation. Bioactive glass can bond with bone minutes after grafting, and silk fibroin, a natural fibrous protein has potential to induce bone regeneration. Hybrid materials that exploit these properties can combine the osteogenic potential and the load-bearing capacity for potential applications in large-load bone defect models.

In a recent study, Swati Midha and co-workers developed a novel 3-D hybrid construct using silk-based inks with different bioactive glass compositions integrated to recreate a bone-mimetic microenvironment that supports osteogenic differentiation of bone marrow mesenchymal stem cell (BMSC) lines in the lab. Now published in Biomedical Materials, IOP Science, the scientists used direct writing instruments to produce the silk fibroin-gelatin-bioactive glass scaffolds (SF-G-BG). The results delivered appropriate cues to regulate the development of customized 3-D human bone constructs in vitro.

'Origami organs' can potentially regenerate tissues

Bioactive tissue paper made from organs is pliable enough to fold into origami structures

Northwestern Medicine scientists and engineers have invented a range of bioactive "tissue papers" made of materials derived from organs that are thin and flexible enough to even fold into an origami bird. The new biomaterials can potentially be used to support natural hormone production in young cancer patients and aid wound healing.

The tissue papers are made from structural proteins excreted by cells that give organs their form and structure. The proteins are combined with a polymer to make the material pliable.

In the study, individual types of tissue papers were made from ovarian, uterine, kidney, liver, muscle or heart proteins obtained by processing pig and cow organs. Each tissue paper had specific cellular properties of the organ from which it was made.

The article describing the tissue paper and its function will be published Aug. 7 in the journal Advanced Functional Materials.

"This new class of biomaterials has potential for tissue engineering and regenerative medicine as well as drug discovery and therapeutics," corresponding author Ramille Shah said. "It's versatile and surgically friendly."

New dental materials developed, with bioactive glass doped with fluoride, to stop degradation of demineralized dentin and evoke remineralization

Salvatore Sauro, Professor of dental biomaterials and minimally invasive dentistry at CEU Cardenal Herrera University, in Spain, has collaborated with several researchers from Finland, Brazil, Belgium, Germany and the UK on the development of innovative dental biomaterials for the regeneration of dental hard tissues.

Bacterial plaque causes tooth decay due to acids produced by different bacteria species; this has trigged an intense research activity for the development of novel restorative biomaterials with protective and self-healing remineralizing properties. In this new study, Salvatore Sauro, a professor of CEU Cardenal Herrera University (Spain) specialized in the development of innovative dental biomaterials, has collaborated with several researchers from Finland, Brazil, Belgium, Germany and the United Kingdom in order to accomplish this target. Indeed, this international group of research generated two new dental restorative biomaterials containing bioactive glasses, and assessed their effectiveness in reducing the enzymatic auto-degradation of collagen fibres and evoking their remineralization.

Silk proteins paired with renewable wood nanocellulose to produce the strongest artificial spider silk yet

Possibly the strongest hybrid silk fibers to date have been created by scientists in Sweden using all-renewable resources. Combining spider silk proteins with nanocellulose from wood, the process offers a low-cost and scalable way to make bioactive materials for a wide range of medical uses.

Published in ACS Nano by researchers from KTH Royal Institute of Technology in Stockholm, the technique brings together the structural and mechanical performance of inexpensive cellulose nanofibrils with the medicinal properties of spider silk, which is difficult and expensive to fabricate on a large scale.

The bioactive properties of spider silk have been known for centuries. In ancient Rome, spider webs were used to dress soldiers' battle wounds. But producing large-scale amounts of spider silk material today is an expensive process that often relies on fossil-based sources.

KTH Researcher My Hedhammar says that by comparison, wood-based nanocellulose is cheap and sustainable. Furthermore, the technique of combining it with only small amounts of spider silk protein yields a biofunctional material that can be used for such medical purposes as promoting cell growth.

A moldable scaffold for bone

A team including researchers at Rensselaer Polytechnic Institute is developing a new material that can be used to replace skull bone lost to injury, surgery, or birth defect. The bioactive foam is malleable when exposed to warm saline (similar to a sponge), allowing surgeons to easily shape it to fit irregular defects in the skull, where it hardens in place. Once implanted in the skull, specially coated pores within the foam attract bone cells, naturally regenerating bone to replace the foam, which dissolves over time.

The foam -- a shape memory polymer coated in a bioactive polydopamine -- is intended as an alternative to materials currently used to treat cranio-maxillofacial gaps. Most commonly, such gaps are filled with a bone graft surgically harvested from the patient, such as from the hip. Such rigid bone grafts are often difficult to harvest, and cannot be readily manipulated to fit within irregularly shaped bone defects, compromising healing.

The research is supported by a four-year $1.9 million grant from the National Institutes of Health (NIH), and is led by Texas A&M University associate professor Melissa Grunlan, who developed the foam.

"This is like trying to fill in a missing puzzle piece with the wrong piece," Grunlan said. "These bone defects can cause tremendous functional problems and aesthetic issues for individuals, so it was recognized that a better treatment would make a big impact."

The glass bonding adhesives market is valued at about USD 3,891.3 million in 2023, and will grow at a rate of 8.7% by the end of this decade, to touch USD 6,857.8 million by 2030. The growth has a lot to do with the use of these agents, the glass is smooth, as there will be no noticeable screws, bulging nuts and bolts. Furthermore, these materials offer protection against corrosion and possess…