Bioactive glasses: where are we and where are we going?

Bioactive glasses caused a revolution in healthcare and paved the way for modern biomaterial-driven regenerative medicine. The first 45S5 glass composition, invented by Larry Hench fifty years ago, was able to bond to living bone and to stimulate osteogenesis through the release of biologically-active ions. 45S5-based glass products have been successfully implanted in millions of patients worldwide, mainly to repair bone and dental defects and, over the years, many other bioactive glass compositions have been proposed for innovative biomedical applications, such as soft tissue repair and drug delivery. The full potential of bioactive glasses seems still yet to be fulfilled, and many of today’s achievements were unthinkable when research began. As a result, the research involving bioactive glasses is highly stimulating and requires a cross-disciplinary collaboration among glass chemists, bioengineers, and clinicians. The present article provides a picture of the current clinical applications of bioactive glasses, and depicts six relevant challenges deserving to be tackled in the near future. We hope that this work can be useful to both early-stage researchers, who are moving with their first steps in the world of bioactive glasses, and experienced scientists, to stimulate discussion about future research and discover new applications for glass in medicine

Potential of bioactive glasses for cardiac and pulmonary tissue engineering

Repair and regeneration of disorders affecting cardiac and pulmonary tissues through tissue-engineering-based approaches is currently of particular interest. On this matter, different families of bioactive glasses (BGs) have recently been given much consideration with respect to treating refractory diseases of these tissues, such as myocardial infarction. The inherent properties of BGs, including their ability to bond to hard and soft tissues, to stimulate angiogenesis, and to elicit antimicrobial effects, along with their excellent biocompatibility, support these newly proposed strategies. Moreover, BGs can also act as a bioactive reinforcing phase to finely tune the mechanical properties of polymer-based constructs used to repair the damaged cardiac and pulmonary tissues. In the present study, we evaluated the potential of different forms of BGs, alone or in combination with other materials (e.g., polymers), in regards to repair and regenerate injured tissues of cardiac and pulmonary systems

Analysis of immumoreactivity of heterologously expressed non-structural protein 4B (NS4B) from Hepatitis C Virus (HCV) genotype 1a

Background: Detection of hepatitis C virus specific antibodies is the initial step in chronic HCV diagnosis. HCV NS4B is among the most immunogenic HCV antigens and has been widely used in commercial Enzyme Immunoassays (EIA). Additionally, NS4B, a key protein in the virus replication, can be an alternative target for antiviral therapy. Objectives: Development of a new method for high-level expression and purification of NS4B coding region was the aim of the report. Materials and Methods: Viral RNA was purified from the serum of an HCV positive patient and NS4B coding region was amplified using nested RT-PCR. PCR products were cloned into pET102/D-TOPO expression vector and transformed into E. coli BL21. Induction was performed by adding 1mM isopropyl-β-D-thiogalactopyranoside (IPTG) to the culture medium. Immunoreactivity of the purified recombinant proteins was evaluated by immunoblotting and indirect enzymelinked immunosorbent assay (ELISA). Results: The recombinant NS4B protein was expressed and its immunoreactivity was confirmed by ELISA and western blotting. Conclusions: The directional TOPO cloning provides an efficient and easy platform for heterologous expression of immunoreactiveHCV NS4B. © 2015 Kowsar Medical Publishing Company. All rights reserved

Establishment of a new immunological method for direct detection of Mycobacterium in solution

Background/PurposeTuberculosis (TB) is a crucial health problem. Prevention of the disease requires rapid diagnosis. Rapid liquid culture systems, nucleic acid amplification tests, and high-performance liquid chromatography (HPLC) are among the rapid tests used for detecting Mycobacterium species. However, these tests are expensive and require extensive equipment and expertise, which is hardly affordable in resource-poor countries. Although direct microscopy is performed routinely as an initial step for detection of the bacteria, it is not sufficiently sensitive. As a result, we thought of establishing a low-cost immunological test that can potentially replace direct microscopy with higher sensitivity and specificity.MethodsThe assay is based on pre-incubation of biotinylated rabbit antibody against Antigen 60 (A60) with a solution containing Bacillus Calmette-Guérin (BCG) or Mycobacterium tuberculosis (MTB) followed by incubation with a streptavidin–alkaline phosphatase (STA–ALP) conjugate. The test is devised in enzyme-linked immunosorbent assay (ELISA) and non-ELISA formats, therefore it does not require extensive facilities and expertise.ResultsThe ELISA format showed a 100-fold improvement in the lower detection limit of BCG compared with direct microscopy. With the non-ELISA formats, there was a 2- and 16-fold improvement for the cartridge assay and the microfuge tube assay, respectively.ConclusionIn conclusion, we successfully detected BCG and MTB in solution using the new immunological method. Our results are very promising and the new immunological method could potentially replace direct microscopy with higher sensitivity and specificity

Nanotechnology for angiogenesis: Opportunities and challenges

Angiogenesis plays a critical role within the human body, from the early stages of life (i.e., embryonic development) to life-threatening diseases (e.g., cancer, heart attack, stroke, wound healing). Many pharmaceutical companies have expended huge efforts on both stimulation and inhibition of angiogenesis. During the last decade, the nanotechnology revolution has made a great impact in medicine, and regulatory approvals are starting to be achieved for nanomedicines to treat a wide range of diseases. Angiogenesis therapies involve the inhibition of angiogenesis in oncology and ophthalmology, and stimulation of angiogenesis in wound healing and tissue engineering. This review aims to summarize nanotechnology-based strategies that have been explored in the broad area of angiogenesis. Lipid-based, carbon-based and polymeric nanoparticles, and a wide range of inorganic and metallic nanoparticles are covered in detail. Theranostic and imaging approaches can be facilitated by nanoparticles. Many preparations have been reported to have a bimodal effect where they stimulate angiogenesis at low dose and inhibit it at higher doses. This journal i

Hydroxyapatite Nanoparticles for Improved Cancer Theranostics

Beyond their well-known applications in bone tissue engineering, hydroxyapatite nanoparticles (HAp NPs) have also been showing great promise for improved cancer therapy. The chemical structure of HAp NPs offers excellent possibilities for loading and delivering a broad range of anticancer drugs in a sustained, prolonged, and targeted manner and thus eliciting lower complications than conventional chemotherapeutic strategies. The incorporation of specific therapeutic elements into the basic composition of HAp NPs is another approach, alone or synergistically with drug release, to provide advanced anticancer effects such as the capability to inhibit the growth and metastasis of cancer cells through activating specific cell signaling pathways. HAp NPs can be easily converted to smart anticancer agents by applying different surface modification treatments to facilitate the targeting and killing of cancer cells without significant adverse effects on normal healthy cells. The applications in cancer diagnosis for magnetic and nuclear in vivo imaging are also promising as the detection of solid tumor cells is now achievable by utilizing superparamagnetic HAp NPs. The ongoing research emphasizes the use of HAp NPs in fabricating three-dimensional scaffolds for the treatment of cancerous tissues or organs, promoting the regeneration of healthy tissue after cancer detection and removal. This review provides a summary of HAp NP applications in cancer theranostics, highlighting the current limitations and the challenges ahead for this field to open new avenues for research

Using bioactive glasses in the management of burns

The management of burn injuries is considered an unmet clinical need and, to date, no fully satisfactory solution exists to this problem. This mini-review aims to explore the potential of bioactive glasses (BGs) for burn care due to the therapeutic effects of their ionic dissolution products. BGs have been studied for more than 40 years and boast a long successful history in the substitution of damaged tissues, especially bone. Considering their exceptional versatility and attractive characteristics, these synthetic materials have also recently been proposed in the treatment of soft tissue-related disorders such as skin wounds. Specifically, improving fibroblast proliferation, inducing angiogenesis, and eliciting antibacterial activity (with the additional advantage of avoiding administration of antibiotics) are all considered as key added values carried by BGs in the treatment of burn injuries. However, some issues deserve careful consideration while proceeding with the research, including the selection of suitable BG compositions, appropriate forms of application (e.g., BG fibers, ointments or composite patches), as well as the procedures for reliable in vivo testing. © 2019 Kargozar, Mozafari, Hamzehlou and Baino

Nanostructured bioactive glasses: A bird's eye view on cancer therapy

Bioactive glasses (BGs) arewell known for their successful applications in tissue engineering and regenerative medicine. Recent experimental studies have shown their potential usability in oncology, either alone or in combination with other biocompatible materials, such as biopolymers. Direct contact with BG particles has been found to cause toxicity and death in specific cancer cells (bone-derived neoplastic stromal cells) in vitro. Nanostructured BGs (NBGs) can be doped with anticancer elements, such as gallium, to enhance their toxic effects against tumor cells. However, the molecular mechanisms and intracellular targets for anticancer compositions of NBGs require further clarification. NBGs have been successfully evaluated for use in various well-established cancer treatment strategies, including cancer hyperthermia, phototherapy, and anticancer drug delivery. Existing results indicate that NBGs not only enhance cancer cell death, but can also participate in the regeneration of lost healthy tissues. However, the application of NBGs in oncology is still in its early stages, and numerous unanswered questions must be addressed. For example, the impact of the composition, biodegradation, size, and morphology of NBGs on their anticancer efficacy should be defined for each type of cancer and treatment strategy. Moreover, it should be more clearly assessed whether NBGs can shrink tumors, slow/stop cancer progression, or cure cancer completely. In this regard, the use of computational studies (in silico methods) is highly recommended to design the most effective glass formulations for cancer therapy approaches and to predict, to some extent, the relevant properties, efficacy, and outcomes. This article is categorized under: Implantable Materials and Surgical Technologies > Nanomaterials and Implants Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease

Bone tissue engineering using human cells: A comprehensive review on recent trends, current prospects, and recommendations

The use of proper cells for bone tissue engineering remains a major challenge worldwide. Cells play a pivotal role in the repair and regeneration of the bone tissue in vitro and in vivo. Currently, a large number of differentiated (somatic) and undifferentiated (stem) cells have been used for bone reconstruction alone or in combination with different biomaterials and constructs (e.g., scaffolds). Although the results of the cell transplantation without any supporting or adjuvant material have been very effective with regard to bone healing. Recent advances in bone scaffolding are now becoming new players affecting the osteogenic potential of cells. In the present study, we have critically reviewed all the currently used cell sources for bone reconstruction and discussed the new horizons that are opening up in the context of cell-based bone tissue engineering strategies. © 2019 by the authors