Angiogenic Rg1 /Sr-Doped TiO2 Nanowire/Poly(Propylene Fumarate) Bone Cement Composites

Radiopaque Crystalline, Non-Crystalline and Nanostructured Bioceramics

Radiopacity is sometimes an essential characteristic of biomaterials that can help clinicians perform follow-ups during pre- and post-interventional radiological imaging. Due to their chemical composition and structure, most bioceramics are inherently radiopaque but can still be doped/mixed with radiopacifiers to increase their visualization during or after medical procedures. The radiopacifiers are frequently heavy elements of the periodic table, such as Bi, Zr, Sr, Ba, Ta, Zn, Y, etc., or their relevant compounds that can confer enhanced radiopacity. Radiopaque bioceramics are also intriguing additives for biopolymers and hybrids, which are extensively researched and developed nowadays for various biomedical setups. The present work aims to provide an overview of radiopaque bioceramics, specifically crystalline, non-crystalline (glassy), and nanostructured bioceramics designed for applications in orthopedics, dentistry, and cancer therapy. Furthermore, the modification of the chemical, physical, and biological properties of parent ceramics/biopolymers due to the addition of radiopacifiers is critically discussed. We also point out future research lacunas in this exciting field that bioceramists can explore further.

Intrinsically radiopaque biomaterial assortments: a short review on the physical principles, X-ray imageability, and state-of-the-art developments

X-ray attenuation ability, otherwise known as radiopacity of a material, could be indisputably tagged as the central and decisive parameter that produces contrast in an X-ray image. Radiopaque biomaterials are vital in the healthcare sector that helps clinicians to track them unambiguously during pre and post interventional radiological procedures. Medical imaging is one of the most powerful resources in the diagnostic sector that aids improved treatment outcomes for patients. Intrinsically radiopaque biomaterials enable themselves for visual targeting/positioning as well as to monitor their fate and further provide the radiologists with critical insights about the surgical site. Moreover, the emergence of advanced real-time imaging modalities is a boon to the contemporary healthcare systems that allow to perform minimally invasive surgical procedures and thereby reduce the healthcare costs and minimize patient trauma. X-ray based imaging is one such technologically upgraded diagnostic tool with many variants like digital X-ray, computed tomography, digital subtraction angiography, and fluoroscopy. In light of these facts, this review is aimed to briefly consolidate the physical principles of X-ray attenuation by a radiopaque material, measurement of radiopacity, classification of radiopaque biomaterials, and their recent advanced applications.

Polymer Scaffolds-Enhanced Bone Regeneration in Osteonecrosis Therapy

Osteonecrosis without effective early treatment eventually leads to the collapse of the articular surface and causes arthritis. For the early stages of osteonecrosis, core decompression combined with bone grafting, is a procedure worthy of attention and clinical trial. And the study of bone graft substitutes has become a hot topic in the area of osteonecrosis research. In recent years, polymers have received more attention than other materials due to their excellent performance. However, because of the harsh microenvironment in osteonecrosis, pure polymers may not meet the stringent requirements of osteonecrosis research. The combined application of polymers and various other substances makes up for the shortcomings of polymers, and to meet a broad range of requirements for application in osteonecrosis therapy. This review focuses on various applying polymers in osteonecrosis therapy, then discusses the development of biofunctionalized composite polymers based on the polymers combined with different bioactive substances. At the end, we discuss their prospects for translation to clinical practice.

Engineered three-dimensional scaffolds for enhanced bone regeneration in osteonecrosis

Osteonecrosis, which is typically induced by trauma, glucocorticoid abuse, or alcoholism, is one of the most severe diseases in clinical orthopedics. Osteonecrosis often leads to joint destruction, and arthroplasty is eventually required. Enhancement of bone regeneration is a critical management strategy employed in osteonecrosis therapy. Bone tissue engineering based on engineered three-dimensional (3D) scaffolds with appropriate architecture and osteoconductive activity, alone or functionalized with bioactive factors, have been developed to enhance bone regeneration in osteonecrosis. In this review, we elaborate on the ideal properties of 3D scaffolds for enhanced bone regeneration in osteonecrosis, including biocompatibility, degradability, porosity, and mechanical performance. In addition, we summarize the development of 3D scaffolds alone or functionalized with bioactive factors for accelerating bone regeneration in osteonecrosis and discuss their prospects for translation to clinical practice.

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Engineered three-dimensional scaffolds boost bone regeneration in osteonecrosis.

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The ideal properties of three-dimensional scaffolds for osteonecrosis treatment are discussed.

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Bioactive factors-functionalized three-dimensional scaffolds are promising bone regeneration devices for osteonecrosis management.

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The challenges and opportunities of engineered three-dimensional scaffolds for osteonecrosis therapy are predicted.

Strontium ranelate simultaneously improves the radiopacity and osteogenesis of calcium phosphate cement

In a minimally invasive surgery of osteoporotic fractures, high radiopacity is necessary to monitor the delivery and positioning of injectable cements and good osteogenesis is indispensable. In this work, strontium ranelate (SrR), an agent for treating osteoporosis, is firstly used as a radiopaque agent for calcium phosphate cement (CPC). The addition of SrR does not affect the hydration products of CPC, but prolonged the setting time and decreased the compressive strength. The injectability of the cement was higher than 85% when SrR content is more than 10 wt%. The radiopacity of CPC is significantly improved by SrR and higher than cortical bone when the content of SrR is more than 5 wt%. The concentration of Sr ions released from CPC is increased by the increasing content of SrR, which is among 17-1329 μM. Moreover, CPCs with SrR significantly promote the osteogenic differentiation of mouse bone marrow mesenchymal stem cells and inhibit the osteoclastogenic differentiation of RAW264.7 cells. Based on its good radiopacity and osteogenesis, suppressed osteoclastogenesis and appropriate physicochemical properties, the radiopaque CPC with more than 10 wt% SrR is prospective to be a promising biomaterial for osteoporotic fracture repairing in minimal invasive surgery.

Preparation and cytocompatibility of a novel bismuth aluminate/calcium phosphate cement with high radiopacity

In a minimally invasive surgery, using a bone cement being radiologically detectable is vital to the success of the procedure and avoiding cement leakage in the early stage. The radiopacity of calcium phosphate cement (CPC) is inadequate, thus limiting its clinic application in this area. In this work, bismuth aluminate (BiA) was employed as a radiopaque agent for CPC. The influences of BiA on physicochemical, radiopaque and in vitro biocompatible properties of CPC were investigated. With the increasing content of BiA, the setting time and the compressive strength of CPC were augmented, while the injectability of the cement pastes was reduced. The radiopacity of CPC was significantly improved by adding more than 6 wt.% BiA. CPC specimens with less than 12 wt.% BiA showed good cellular affinity. Moreover, the CPC containing 6 and 9 wt.% BiA promoted the cell growth and ALP activity of mouse bone marrow mesenchymal stem cells when compared with the control. On the basis of its improved radiopacity and cytocompatibility, the radiopaque CPC with 6 ~ 9 wt.% BiA is expected to be a potential substitute for bone defect restoration via minimally invasive surgery. CPC with bismuth aluminate reveals better radiopacity and cell affinity along with proper physicochemical properties.