Bioreactors Design, Types, Influencing Factors and Potential Application in Dentistry. A Literature Review

Recent advancement in vascularized tissue-engineered bone based on materials design and modification

Bone is one of the most vascular network-rich tissues in the body and the vascular system is essential for the development, homeostasis, and regeneration of bone. When segmental irreversible damage occurs to the bone, restoring its vascular system by means other than autogenous bone grafts with vascular pedicles is a therapeutic challenge. By pre-generating the vascular network of the scaffold in vivo or in vitro, the pre-vascularization technique enables an abundant blood supply in the scaffold after implantation. However, pre-vascularization techniques are time-consuming, and in vivo pre-vascularization techniques can be damaging to the body. Critical bone deficiencies may be filled quickly with immediate implantation of a supporting bone tissue engineered scaffold. However, bone tissue engineered scaffolds generally lack vascularization, which requires modification of the scaffold to aid in enhancing internal vascularization. In this review, we summarize the relationship between the vascular system and osteogenesis and use it as a basis to further discuss surgical and cytotechnology-based pre-vascularization strategies and to describe the preparation of vascularized bone tissue engineered scaffolds that can be implanted immediately. We anticipate that this study will serve as inspiration for future vascularized bone tissue engineered scaffold construction and will aid in the achievement of clinical vascularized bone.

Antibiofilm properties of silver nanoparticles incorporated into polymethyl methacrylate used for dental applications

BACKGROUND

Acrylic resins used in dental and biomedical applications do not have antimicrobial properties, their surface is susceptible to colonization of microorganisms.

OBJECTIVE

The aim of this study was to evaluate the antibiofilm properties of silver nanoparticles (AgNPs) deposited in a polymethyl methacrylate (PMMA) surface against a Staphylococcus aureus biofilm.

METHODS

The PMMA was impregnated with AgNPs by using the in-situ polymerization method. To determine the solubility of the incorporated silver (Ag+) atomic absorption spectrophotometry was used (AAS) at 24 h, 48 h, 7 days, and 30 days. Thirty specimens of PMMA with AgNPs and without NP (control group) were assembled in the CDC Biofilm Bioreactor system with a cell suspension of S. aureus. The specimens were removed at 6, 12, 24, 48, and 72 h to determine the viability profile and quantify the Arbitrary Fluorescence Units (AFU).

RESULTS

The AgNPs showed an irregular and quasispherical shape with an average size of 25 nm. AAS analysis demonstrated a low solubility of Ag+. The formation of the S. aureus biofilm increased as the evaluation periods continued up to 72 h. The experimental group showed poor growth, and a decrease in the intensity of the fluorescence demonstrated a statistically significant inhibition of the formation of the biofilm (P < 0.05) in relation to the control group at 6, 12, 24, 48, and 72 h.

CONCLUSION

AgNPs incorporated into PMMA decreased the growth and maturation of S. aureus biofilm.

Genetic Manipulation and Bioreactor Culture of Plants as a Tool for Industry and Its Applications

In recent years, there has been a considerable increase in interest in the use of transgenic plants as sources of valuable secondary metabolites or recombinant proteins. This has been facilitated by the advent of genetic engineering technology with the possibility for direct modification of the expression of genes related to the biosynthesis of biologically active compounds. A wide range of research projects have yielded a number of efficient plant systems that produce specific secondary metabolites or recombinant proteins. Furthermore, the use of bioreactors allows production to be increased to industrial scales, which can quickly and cheaply deliver large amounts of material in a short time. The resulting plant production systems can function as small factories, and many of them that are targeted at a specific operation have been patented. This review paper summarizes the key research in the last ten years regarding the use of transgenic plants as small, green biofactories for the bioreactor-based production of secondary metabolites and recombinant proteins; it simultaneously examines the production of metabolites and recombinant proteins on an industrial scale and presents the current state of available patents in the field.

Current Trends in In Vitro Modeling to Mimic Cellular Crosstalk in Periodontal Tissue

Clinical evidence indicates that in physiological and therapeutic conditions a continuous remodeling of the tooth root cementum and the periodontal apparatus is required to maintain tissue strength, to prevent damage, and to secure teeth anchorage. Within the tooth's surrounding tissues, tooth root cementum and the periodontal ligament are the key regulators of a functional tissue homeostasis. While the root cementum anchors the periodontal fibers to the tooth root, the periodontal ligament itself is the key regulator of tissue resorption, the remodeling process, and mechanical signal transduction. Thus, a balanced crosstalk of both tissues is mandatory for maintaining the homeostasis of this complex system. However, the mechanobiological mechanisms that shape the remodeling process and the interaction between the tissues are largely unknown. In recent years, numerous 2D and 3D in vitro models have sought to mimic the physiological and pathophysiological conditions of periodontal tissue. They have been proposed to unravel the underlying nature of the cell-cell and the cell-extracellular matrix interactions. The present review provides an overview of recent in vitro models and relevant biomaterials used to enhance the understanding of periodontal crosstalk and aims to provide a scientific basis for advanced regenerative strategies.