Abstract:Biocomposite scaffolds of lithium (Li)-containing mesoporous bioglass and monomethoxy poly(ethylene glycol)-poly(D,L-lactide-
co
-glycolide)-poly(L-lysine) (mPEG-PLGA-
b
-PLL) copolymer were fabricated in this study. The results showed that the water absorption and degradability of Li-containing mesoporous bioglass/mPEG-PLGA-
b
-PLL composite (l-MBPC) scaffolds were obviously higher than Li-containing bioglass/mPEG-PLGA
-b
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“…In addition, histological staining indicated that the new bone was immature bone or osteoid. This may be related to the porosity, particle size and/or surface topography of BCP, which all play key roles in its osteoinduction [ 40 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, we expect BCP to show more active bone regeneration than β-TCP alone. Other factors, including surface topography, porosity and particle size, may also affect the performance of bone graft materials and were considered in this study [39,40]. Currently, ideal bone induction biomaterials are considered to exhibit three key characteristics [41].…”
Section: Mesenchymal Stem Cell (Msc) Recruitment and Osteoblast Diffementioning
The immune response of a biomaterial determines its osteoinductive effect. Although the mechanisms by which some immune cells promote regeneration have been revealed, the biomaterial-induced immune response is a dynamic process involving multiple cells. Currently, it is challenging to accurately regulate the innate and adaptive immune responses to promote osteoinduction in biomaterials. Herein, we investigated the roles of macrophages and dendritic cells (DCs) during the osteoinduction of biphasic calcium phosphate (BCP) scaffolds. We found that osteoinductive BCP directed M2 macrophage polarization and inhibited DC maturation, resulting in low T cell response and efficient osteogenesis. Accordingly, a dual-targeting nano-in-micro scaffold (BCP loaded with gold nanocage, BCP-GNC) was designed to regulate the immune responses of macrophages and DCs. Through a dual-wavelength photosensitive switch, BCP-GNC releases interleukin-4 in the early stage of osteoinduction to target M2 macrophages and then releases dexamethasone in the later stage to target immature DCs, creating a desirable inflammatory environment for osteogenesis. This study demonstrates that biomaterials developed to have specific regulatory capacities for immune cells can be used to control the early inflammatory responses of implanted materials and induce osteogenesis.
“…In addition, histological staining indicated that the new bone was immature bone or osteoid. This may be related to the porosity, particle size and/or surface topography of BCP, which all play key roles in its osteoinduction [ 40 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Therefore, we expect BCP to show more active bone regeneration than β-TCP alone. Other factors, including surface topography, porosity and particle size, may also affect the performance of bone graft materials and were considered in this study [39,40]. Currently, ideal bone induction biomaterials are considered to exhibit three key characteristics [41].…”
Section: Mesenchymal Stem Cell (Msc) Recruitment and Osteoblast Diffementioning
The immune response of a biomaterial determines its osteoinductive effect. Although the mechanisms by which some immune cells promote regeneration have been revealed, the biomaterial-induced immune response is a dynamic process involving multiple cells. Currently, it is challenging to accurately regulate the innate and adaptive immune responses to promote osteoinduction in biomaterials. Herein, we investigated the roles of macrophages and dendritic cells (DCs) during the osteoinduction of biphasic calcium phosphate (BCP) scaffolds. We found that osteoinductive BCP directed M2 macrophage polarization and inhibited DC maturation, resulting in low T cell response and efficient osteogenesis. Accordingly, a dual-targeting nano-in-micro scaffold (BCP loaded with gold nanocage, BCP-GNC) was designed to regulate the immune responses of macrophages and DCs. Through a dual-wavelength photosensitive switch, BCP-GNC releases interleukin-4 in the early stage of osteoinduction to target M2 macrophages and then releases dexamethasone in the later stage to target immature DCs, creating a desirable inflammatory environment for osteogenesis. This study demonstrates that biomaterials developed to have specific regulatory capacities for immune cells can be used to control the early inflammatory responses of implanted materials and induce osteogenesis.
“…Membranes used in GBR are expected to have multiple functions such as inducing proliferation/differentiation of osteoblasts while inhibiting that of osteoclasts, and antibacterial properties. Several reports indicate that Li that can promote bone formation ( Zamani et al, 2009 ; Chen and Alman, 2009 ; Cai et al, 2015 ; Zhang et al, 2018 ), and a few ( Tay et al, 2012 ; Moghanian et al, 2018 ) imply that it has antibacterial potential, thus it may be suitable for improving membrane properties. To our knowledge, Li has not been incorporated into electrospun membranes before.…”
Lithium (Li) reportedly has anti-bacterial properties. Thus, it is an ideal option to modify barrier membranes used for guided bone regeneration to inhibit the bacterial adhesion. The aims of this study were to fabricate and characterize nanofibrous poly(L-lactic acid) (PLLA) membranes containing Li, and investigate their antibacterial effects on Porphyromonas gingivalis and Actinobacillus actinomycetemcomitans in vitro. Li (5%Li, 10%Li, and 15%Li)-loaded nanofibrous PLLA membranes were fabricated using an electrospinning technique, and characterized via scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, a contact angle measuring device, and a universal testing machine. Sustained release of Li ions was measured over a 14-day period and biocompatibility of the Li-PLLA membranes was investigated. Evaluation of bacterial adhesion and antibacterial activity were conducted by bacterial colony counting, LIVE/DEAD staining and inhibition zone method using P.gingivalis and A.actinomycetemcomitans. Of the three Li-loaded membranes assessed, the 10%Li-PLLA membrane had the best mechanical properties and biocompatibility. Adhesion of both P.gingivalis and A.actinomycetemcomitans on Li-PLLA membranes was significantly lower than adhesion on pure PLLA membranes, particularly with regard to the 10%Li and 15%Li membranes. Significant antibacterial activity of Li-PLLA were also observed against according to the inhibition zone test. Given their better mechanical properties, biocompatibility, and antibacterial activity, PLLAs with 10%Li are a better choice for future clinical utilization. The pronounced antibacterial effects of Li-loaded PLLA membranes sets the stage for further application in guided bone regeneration.
“…2018, 19, 826; doi:10.3390/ijms19030826 lithium application exhibited beneficial effects on bone healing following distraction osteotomy in the tibia of rats. Bone mineral density, quantity of newly formed mature bone tissue and bone mass regeneration were increased in rats who received a lithium solution through gastric gavage in comparison to those receiving a saline solution, pointing to accelerated callus ossification and bone healing mediated by lithium[179].To further utilize the beneficial effects of lithium on bone regeneration, various biodegradable lithium containing scaffolds have been developed and tested for their potential in bone regeneration, whereby preliminary experiments on lithium release, toxicity and osteoblastic cell activity on such scaffolds were promising[180,181]. In vitro experiments comparing pure HAp with lithium-doped…”
The regeneration of bone tissue is a main purpose of most therapies in dental medicine. For bone regeneration, calcium phosphate (CaP)-based substitute materials based on natural (allo- and xenografts) and synthetic origins (alloplastic materials) are applied for guiding the regeneration processes. The optimal bone substitute has to act as a substrate for bone ingrowth into a defect, while it should be resorbed even in the time frame needed for complete regeneration up to the condition of restitution ad integrum. In this context, the modes of action of CaP-based substitute materials have been frequently investigated and it has been shown that such materials strongly influence regenerative processes such as osteoblast growth or differentiation and also on osteoclastic resorption due to different physicochemical properties of the materials. However, the material characteristics needed for the required ratio between the formation of new bone tissue and material degradation has not been found until now. The addition of different substances such as collagen or growth factors and also of different cell types have already been tested but did not allow for sufficient or prompt application. Moreover, metals or metal ions are differently used as basis or as supplement for different materials in the field of bone regeneration. Moreover, it has already been shown that different metal ions are integral components of bone tissue playing functional roles in the physiological cellular environment as well as in the course of bone healing. The present review focuses on frequently used metals as integral parts of materials designated for bone regeneration with the aim to give an overview of currently existing knowledge about the effects of metals in the field of bone regeneration.
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