Cytotoxicity of corrosion products of degradable Fe-based stents: relevance of pH and insoluble products

Effect of TiC Nanoparticles on a Zn-Al-Cu System for Biodegradable Cardiovascular Stent Applications

Despite being a weaker metal, zinc has become an increasingly popular candidate for biodegradable implant applications due to its suitable corrosion rate and biocompatibility. Previous studies have experimented with various alloy elements to improve the overall mechanical performance of pure Zn without compromising the corrosion performance and biocompatibility; however, the thermal stability of biodegradable Zn alloys has not been widely studied. In this study, TiC nanoparticles were introduced for the first time to a Zn-Al-Cu system. After hot rolling, TiC nanoparticles were uniformly distributed in the Zn matrix and effectively enabled phase control during solidification. The Zn-Cu phase, which was elongated and sharp in the reference alloy, became globular in the nanocomposite. The strength of the alloy, after introducing TiC nanoparticles, increased by 31% from 259.7 to 340.3 MPa, while its ductility remained high at 49.2% elongation to failure. Fatigue performance also improved greatly by adding TiC nanoparticles, increasing the fatigue limit by 47.6% from 44.7 to 66 MPa. Furthermore, TiC nanoparticles displayed excellent phase control capability during body-temperature aging. Without TiC restriction, Zn-Cu phases evolved into dendritic morphologies, and the Al-rich eutectic grew thicker at grain boundaries. However, both Zn-Cu and Al-rich eutectic phases remained relatively unchanged in shape and size in the nanocomposite. A combination of exceptional tensile properties, improved fatigue performance, better long-term stability with a suitable corrosion rate, and excellent biocompatibility makes this new Zn-Al-Cu-TiC material a promising candidate for biodegradable stents and other biodegradable applications.

Recent advances in Fe-based bioresorbable stents: Materials design and biosafety

Fe-based materials have received more and more interests in recent years as candidates to fabricate bioresorbable stents due to their appropriate mechanical properties and biocompatibility. However, the low degradation rate of Fe is a serious limitation for such application. To overcome this critical issue, many efforts have been devoted to accelerate the corrosion rate of Fe-based stents, through the structural and surface modification of Fe matrix. As stents are implantable devices, the released corrosion products (Fe2+ ions) in vessels may alter the metabolism, by generating reactive oxygen species (ROS), which might in turn impact the biosafety of Fe-based stents. These considerations emphasize the importance of combining knowledge in both materials and biological science for the development of efficient and safe Fe-based stents, although there are still only limited numbers of reviews regarding this interdisciplinary field. This review aims to provide a concise overview of the main strategies developed so far to design Fe-based stents with accelerated degradation, highlighting the fundamental mechanisms of corrosion and the methods to study them as well as the reported approaches to accelerate the corrosion rates. These approaches will be divided into four main sections, focusing on (i) increased active surface areas, (ii) tailored microstructures, (iii) creation of galvanic reactions (by alloying, ion implantation or surface coating of noble metals) and (iv) decreased local pH induced by degradable surface organic layers. Recent advances in the evaluation of the in vitro biocompatibility of the final materials and ongoing in vivo tests are also provided.

Physiomimetic biocompatibility evaluation of directly printed degradable porous iron implants using various cell types

Additively manufactured (AM) degradable porous metallic biomaterials offer unique opportunities for satisfying the design requirements of an ideal bone substitute. Among the currently available biodegradable metals, iron has the highest elastic modulus, meaning that it would benefit the most from porous design. Given the successful preclinical applications of such biomaterials for the treatment of cardiovascular diseases, the moderate compatibility of AM porous iron with osteoblast-like cells, reported in earlier studies, has been surprising. This may be because, as opposed to static in vitro conditions, the biodegradation products of iron in vivo are transported away and excreted. To better mimic the in situ situations of biodegradable biomaterials after implantation, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static conditions to the conditions with dynamic in situ-like fluid flow perfusion in a bioreactor. Furthermore, the compatibility of these scaffolds with four different cell types was evaluated to better understand the implications of these implants for the complex process of natural wound healing. These included endothelial cells, L929 fibroblasts, RAW264.7 macrophage-like cells, and osteoblastic MG-63 cells. The biodegradation rate of the scaffolds was significantly increased in the perfusion bioreactor as compared to static immersion. Under either condition, the compatibility with L929 cells was the best. Moreover, the compatibility with all the cell types was much enhanced under physiomimetic dynamic flow conditions as compared to static biodegradation. Our study highlights the importance of physiomimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro. STATEMENT OF SIGNIFICANCE: Additively manufactured (AM) degradable porous metals offer unique opportunities for the treatment of large bony defects. Despite the successful preclinical applications of biodegradable iron in the cardiovascular field, the moderate compatibility of AM porous iron with osteoblast-like cells was reported. To better mimic the in vivo condition, we compared the biodegradation behavior and cytocompatibility of AM porous iron under static condition to dynamic perfusion. Furthermore, the compatibility of these scaffolds with various cell types was evaluated to better simulate the process of natural wound healing. Our study suggests that AM porous iron holds great promise for orthopedic applications, while also highlighting the importance of physio-mimetic culture conditions and cell type selection when evaluating the cytocompatibility of degradable biomaterials in vitro.

Vitamin E protective effects on genomic and cellular damage caused by paediatric preventive supplementation for anaemia: an experimental model

Iron deficiency is the leading cause of anaemia. In Argentina, the prevalence of anaemia and iron deficiency is very high; for that reason, the Argentine Society of Pediatrics recommends daily ferrous sulphate supplementation as a preventive treatment strategy. Alternatively, weekly ferrous sulphate supplementation has also been shown to be effective for anaemia prevention. Excess iron could be related to oxidative stress, which may in turn cause cytomolecular damage. Both can be prevented with vitamin E supplementation. We evaluated the effect of both daily and weekly ferrous sulphate supplementation combined with two doses of vitamin E on cell viability, oxidative stress and cytomolecular damage in peripheral blood cultured in vitro. The experimental design included the following groups: untreated negative control, two vitamin E controls (8·3 and 16·6 µg/ml), weekly ferrous sulphate supplementation (0·55 mg/ml) with each vitamin E dose, daily ferrous sulphate supplementation (0·14 mg/ml) with each vitamin E dose and a positive control. Daily ferrous sulphate supplementation decreased cell viability and increased the levels of reactive oxygen species, lipid peroxidation and cytomolecular damage (P < 0·5) compared with the weekly supplementation, probably due to the excess iron observed in the former. Vitamin E seemed to reduce ferrous sulphate-induced oxidative stress and genomic damage.

Experimental study on novel biodegradable Zn-Fe-Si alloys

Bioabsorbable metals are increasingly attracting attention for their potential use as materials for degradable implant devices. Zinc (Zn) alloys have shown great promises due to their good biocompatibility and favorable degradation rate. However, it has been difficult to maintain an appropriate balance among strength, ductility, biocompatibility, and corrosion rate for Zn alloys historically. In this study, the microstructure, chemical composition, mechanical properties, biocompatibility, and corrosion rate of a new ternary zinc-iron-silicon (Zn-Fe-Si) alloy system was studied as a novel material for potential biodegradable implant applications. The results demonstrated that the in situ formed Fe-Si intermetallic phases enhanced the mechanical strength of the material while maintaining a favorable ductility. With Fe-Si reinforcements, the microhardness of the Zn alloys was enhanced by up to 43%. The tensile strength was increased by up to 76% while elongation to failure remained above 30%. Indirect cytotoxicity testing showed the Zn-Fe-Si system had good biocompatibility. Immersion testing revealed the corrosion rate of Zn-Fe-Si system was not statistically different from pure Zn. To understand the underlying phase formation mechanism, the reaction process in this ternary system during the processing was also studied via phase evolution and Gibbs free energy analysis. The results suggest the Zn-Fe-Si ternary system is a promising new material for bioabsorbable metallic medical devices.

Utility of Biogenic Iron and Its Bimetallic Nanocomposites for Biomedical Applications: A Review

Nanotechnology mainly deals with the production and application of compounds with dimensions in nanoscale. Given their dimensions, these materials have considerable surface/volume ratios, and hence, specific characteristics. Nowadays, environmentally friendly procedures are being proposed for fabrication of Fe nanoparticles because a large amount of poisonous chemicals and unfavorable conditions are needed to prepare them. This work includes an inclusive overview on the economical and green procedures for the preparation of such nanoparticles (flower, fruits, tea, carbohydrates, and leaves). Pure and bimetallic iron nanoparticles, for instance, offer a high bandwidth and excitation binding energy and are applicable in different areas ranging from antibacterial, anticancer, and bioimaging agents to drug delivery systems. Preparation of nano-sized particles, such as those of Fe, requires the application of high quantities of toxic materials and harsh conditions, and naturally, there is a tendency to develop more facile and even green pathways (Sultana, Journal of Materials Science & Technology, 2013, 29, 795–800; Bushra et al., Journal of hazardous materials, 2014, 264, 481–489; Khan et al., Ind. Eng. Chem. Res., 2015, 54, 76–82). This article tends to provide an overview on the reports describing green and biological methods for the synthesis of Fe nanoparticles. The present review mainly highlights selenium nanoparticles in the biomedical domain. Specifically, this review will present detailed information on drug delivery, bioimaging, antibacterial, and anticancer activity. It will also focus on procedures for their green synthesis methods and properties that make them potential candidates for various biomedical applications. Finally, we provide a detailed future outlook.

Accelerated biodegradation of iron-based implants via tantalum-implanted surface nanostructures

In recent years, pure iron (Fe) has attracted significant attention as a promising biodegradable orthopedic implant material due to its excellent mechanical and biological properties. However, in physiological conditions, Fe has an extremely slow degradation rate with localized and irregular degradation, which is problematic for practical applications. In this study, we developed a novel combination of a nanostructured surface topography and galvanic reaction to achieve uniform and accelerated degradation of an Fe implant. The target-ion induced plasma sputtering (TIPS) technique was applied on the Fe implant to introduce biologically compatible and electrochemically noble tantalum (Ta) onto its surface and develop surface nano-galvanic couples. Electrochemical tests revealed that the uniformly distributed nano-galvanic corrosion cells of the TIPS-treated sample (nano Ta–Fe) led to relatively uniform and accelerated surface degradation compared to that of bare Fe. Furthermore, the mechanical properties of nano Ta–Fe remained almost constant during a long-term in vitro immersion test (~40 weeks). Biocompatibility was also assessed on surfaces of bare Fe and nano Ta–Fe using in vitro osteoblast responses through direct and indirect contact assays and an in vivo rabbit femur medullary cavity implantation model. The results revealed that nano Ta–Fe not only enhanced cell adhesion and spreading on its surface, but also exhibited no signs of cellular or tissue toxicity. These results demonstrate the immense potential of Ta-implanted surface nanostructures as an effective solution for the practical application of Fe-based orthopedic implants, ensuring long-term biosafety and clinical efficacy.

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The degradation rate of nanostructured Fe implants was accelerated by TIPS technique.

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Ta ions were accelerated strongly toward the Fe surface by TIPS process.

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Nano Ta–Fe showed long-term mechanical stability and accelerated degradation rate.

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Nanostructured Ta–Fe surface showed enhanced in vitro and in vivo cellular responses.

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Ta-implanted Fe is a promising material for biodegradable orthopedic implants.

Injectable thioketal-containing hydrogel dressing accelerates skin wound healing with the incorporation of reactive oxygen species scavenging and growth factor release

Wound healing is a complex dynamic process. During the occurrence of skin injury, the excessive reactive oxygen species (ROS) level is associated with sustained inflammatory response, which limits efficient wound repair. Although multifunctional hydrogels are considered ideal wound dressings due to their unique advantages, the development of hydrogel dressings with rapid gelling rates, shape adaptation, and antioxidant function is still a vital challenge. In this work, a ROS-responsive injectable polyethylene glycol hydrogel containing thioketal bonds (PEG-TK hydrogel) was synthesized and utilized to deliver epidermal growth factor (EGF). We adopted bio-orthogonal click chemistry for crosslinking the polymer chains to obtain the EGF@PEG-TK hydrogel with fast gelation time, injectability and shape-adaptability. More interestingly, the thioketal bonds in the PEG-TK hydrogel not only scavenged excessive ROS in the wound sites but also achieved responsive and controlled EGF release to facilitate regeneration. The EGF@PEG-TK hydrogel treatment offered the benefits of protecting cells from oxidative stress, accelerating wound closure, and reducing scar formation in the full-thickness skin defect model. This work provides a promising strategy for developing antioxidant hydrogel dressing for facilitating the repair of wounds.

Insight into the bioabsorption of Fe-based materials and their current developments in bone applications

Iron (Fe) and Fe-based materials have been vigorously explored in orthopedic applications in the past decade mainly owing to their promising mechanical properties including high yield strength, elastic modulus and ductility. Nevertheless, their corrosion products and low corrosion kinetics are the major concerns that need to be improved further despite their appealing mechanical strengths. The current studies on porous Fe-based scaffolds show an improved corrosion rate but the in vitro biocompatibility is still problematic in general. Unlike the Mg implants, the biodegradation and bioabsorption of Fe-based implants are still not well described. This vague issue could implicate the development of Fe-based materials as potential medical implants as they have not reached the clinical trial stage yet. Thus, there is a need to understand in-depth the Fe corrosion behavior and its bioabsorption mechanism to facilitate the material design of Fe-based scaffolds and further improve its biocompatibility. This manuscript provides an important insight into the basic bioabsorption of the multi-ranged Fe-based corrosion products with a review of the latest progress on the corrosion & in vitro biocompatibility of porous Fe-based scaffolds together with the remaining challenges and the perspective on the future direction.

Six-Month Long In Vitro Degradation Tests of Biodegradable Twinning-Induced Plasticity Steels Alloyed with Ag for Stent Applications

Twinning-induced plasticity (TWIP) Fe-Mn-C steels are biodegradable metals with far superior mechanical properties to any biodegradable metal, including Mg alloys, used in commercially available devices. For this reason, the use of Fe-Mn-C alloys to produce thinner and thinner implants can be exploited for overcoming the device size limitations that biodegradable stents still present. However, Fe-Mn steels are known to form a phosphate layer on their surface over long implantation times in animals, preventing device degradation in the required timeframe. The introduction of second phases in such alloys to promote galvanic coupling showed a short-term promise, and particularly the use of Ag looked especially effective. Nonetheless, the evolution of the corrosion mechanism of quaternary Fe-Mn-C-Ag alloys over time is still unknown. This study aims at understanding how corrosion changes over time for a TWIP steel alloyed with Ag using a simple static immersion setup. The presence of Ag promoted some galvanic coupling just in the first week of immersion; this effect was then suppressed by the formation of a mixed carbonate/hydroxide layer. This layer partly detached after 2 months and was replaced by a stable phosphate layer, over which a new carbonate/hydroxide formed after 4 months, effectively hindering the sample degradation. Attachment of phosphates to the surface matches 1-year outcomes from animal tests reported by other authors, but this phenomenon cannot be predicted using immersion up to 28 days. These results demonstrate that immersion tests of Fe-based degradable alloys can be related to animal tests only when they are carried out for a sufficiently long time and that galvanic coupling with Ag is not a viable strategy in the long term. Future works should focus more on surface modifications to control the interfacial behavior rather than alloying in the bulk.

Effect of degradation products of iron-bioresorbable implants on the physiological behavior of macrophages in vitro

The degradation of bioresorbable metals in vivo changes the physicochemical properties in the environment of an implant, such as a stent in the artery wall, and may induce the alteration of the functions of the surrounding cells. The Fe-degradation, from bioresorbable stents, is a particularly intricate process because it leads to the release of soluble (SDP) and insoluble degradation products (IDP) of varied composition. Macrophages are involved in the resorption of the exogenous agents coming from degradation of these materials. In the present work an Fe⁰ ring, made with a pure Fe wire, in contact with macrophage cell cultures was used to simulate the behaviour of a biodegradable Fe-based implant in a biological environment. Non-invasive time-lapse optical microscopy was applied to obtain images of macrophages exposed to Fe-degradation products, without using staining to avoid distortions and artefacts. It was noticed that as metal degraded, the IDP formed in situ accumulated close to the Fe⁰ ring. In this zone, the macrophages showed a dynamic process of uptake of dark Fe-containing products, confirmed by SEM-EDX. These macrophages showed alterations in the morphology and decrease in the motility and viability. The inability of the macrophages to move and to degrade the engulfed products caused a long persistence of IDP in the zone closest to the metal. The deleterious effects of IDP accumulated close to the ring, were significantly worse than those observed in the experiments made with (1) concentrated salt solutions (Fe³⁺ salt 3 mM), with the same amount of precipitates but uniformly distributed in the well, and (2) diluted salt solutions (Fe³⁺ salt 1 mM) with mainly soluble species. The results were confirmed by standard staining protocols that revealed dead cells close to the Fe⁰ ring and oxidative stress in cells exposed to both soluble and insoluble species.

Development of a novel biodegradable porous iron-based implant for bone replacement

Bone replacement and osteosynthesis require materials which can at least temporarily bear high mechanical loads. Ideally, these materials would eventually degrade and would be replaced by bone deposited from the host organism. To date several metals, notably iron and iron-based alloys have been identified as suitable materials because they combine high strength at medium corrosion rates. However, currently, these materials do not degrade within an appropriate amount of time. Therefore, the aim of the present study is the development of an iron-based degradable sponge-like (i.e. cellular) implant for bone replacement with biomechanically tailored properties. We used a metal powder sintering approach to manufacture a cylindrical cellular implant which in addition contains phosphor as an alloying element. No corrosion inhibiting effects of phosphorus have been found, the degradation rate was not altered. Implant prototypes were tested in an animal model. Bone reaction was investigated at the bone-implant-interface and inside the cellular spaces of the implant. Newly formed bone was growing into the cellular spaces of the implant after 12 months. Signs of implant degradation were detected but after 12 months, no complete degradation could be observed. In conclusion, iron-based open-porous cellular biomaterials seem promising candidates for the development of self-degrading and high load bearing bone replacement materials.

Evaluation of in vitro and in vivo biocompatibility of iron produced by powder metallurgy

Biodegradable metallic materials (BMMs) are expected to corrode gradually in vivo after providing the structural support to the tissue during its regeneration and healing processes. These characteristics make them promising candidates for use in stents. These endoprostheses are produced from metal alloys by casting and thermomechanical treatment. Since porous alloys and metals have less corrosion resistance than dense ones, the use of powder metallurgy becomes an option to produce them. Among the metals, iron has been proposed as a material in the manufacturing of stents because of its mechanical properties. However, even then it is unclear what toxicity threshold is safe to the body. Thus, the objective of this research was to verify the biocompatibility of sintered 99.95% and 99.5% pure iron by powder metallurgy in vitro with Adipose-derived mesenchymal stromal cells (ADSCs) and in vivo with a Wistar rat model. Herein, characterizations of iron powder samples produced by the powder metallurgy and the process parameters as compression pressure, atmosphere, sintering time and temperature were determined to evaluate the potential of production of biodegradable implants. The samples obtained from pure iron were submitted to tests of green and sintered density, porosity, microhardness, hardness and metallography. The biocompatibility study was performed by indirect and direct cell culture with iron. The effects of corrosion products of iron on morphology, viability, and proliferation of ADSCs were evaluated in vitro. Hemolysis assay was performed to verify the hemocompatibility of the samples. In vivo biocompatibility was evaluated after pure iron discs were implanted subcutaneously into the dorsal area of Wistar rats that were followed up to 6 months. The results presented in this paper validated the potential to produce biodegradable medical implants by powder metallurgy. Both iron samples were hemocompatible and biocompatible in vitro and in vivo, although the 99.95% iron had better performance in vitro than 99.5%.

Long-Term Efficacy of Biodegradable Metal-Polymer Composite Stents After the First and the Second Implantations into Porcine Coronary Arteries

A biodegradable coronary stent is expected to eliminate the adverse events of an otherwise eternally implanting material after vessel remodeling. Both biocorrodible metals and biodegradable polymers have been tried as the matrix of the new-generation stent. Herein, we utilized a metal-polymer composite material to combine the advantages of the high mechanical strength of metals and the adjustable degradation rate of polymers to prepare the biodegradable stent. After coating polylactide (PLA) on the surface of iron, the degradation of iron was accelerated significantly owing to the decrease of local pH resulting from the hydrolysis of PLA, etc. We implanted the metal-polymer composite stent (MPS) into the porcine artery and examined its degradation in vivo, with the corresponding metal-based stent (MBS) as a control. Microcomputed tomography (micro-CT), coronary angiography (CA), and optical coherence tomography (OCT) were performed to observe the stents and vessels during the animal experiments. The MPS exhibited faster degradation than MBS, and the inflammatory response of MPS was acceptable 12 months after implantation. Additionally, we implanted another MPS after 1-year implantation of the first MPS to investigate the result of the MPS in the second implantation. The feasibility of the biodegradable MPS in second implantation in mammals was also confirmed.

Resorbable implants in pediatric fracture treatment

Pediatric osteosynthesis has developed over the last 20 years, thereby reducing medical and economic burden, including long and expensive hospitalization. Currently, conventional and rigid alloying systems such as titanium are used for stabilization of bone fractures in children. In many cases, implants must be removed, as otherwise growth would be impeded. Biodegradable implant materials exhibit beneficial properties and would make a second removal surgery unnecessary. In the following article, we will give an overview of implant materials that are currently used in pediatric traumatology with a focus on Mg-based implants. Furthermore, we will discuss current scientific knowledge on resorbable implants, including results from pre-clinics and clinics.

R, T. S. N. SN. Protecting electrochemical degradation of pure iron using zinc phosphate coating for biodegradable implant applications

The surface of pure iron was modified with the formation of a zinc phosphate coatingviaa chemical conversion method for biomedical applications.

Bio-Functional Design, Application and Trends in Metallic Biomaterials

Introduction of metals as biomaterials has been known for a long time. In the early development, sufficient strength and suitable mechanical properties were the main considerations for metal implants. With the development of new generations of biomaterials, the concepts of bioactive and biodegradable materials were proposed. Biological function design is very import for metal implants in biomedical applications. Three crucial design criteria are summarized for developing metal implants: (1) mechanical properties that mimic the host tissues; (2) sufficient bioactivities to form bio-bonding between implants and surrounding tissues; and (3) a degradation rate that matches tissue regeneration and biodegradability. This article reviews the development of metal implants and their applications in biomedical engineering. Development trends and future perspectives of metallic biomaterials are also discussed.

Magnesium-based biodegradable alloys: Degradation, application, and alloying elements

In recent years, the paradigm about the metal with improved corrosion resistance for application in surgery and orthopedy was broken. The new class of biodegradable metal emerges as an alternative for biomedical implants. These metals corrode gradually with an appropriate host response and release of corrosion products. And it is absolutely necessary to use essential metals metabolized by hosting organism with local and general nontoxic effect. Magnesium serves this aim best; it plays the essential role in body metabolism and should be completely excreted within a few days after degradation. This review summarizes data from Mg discovery and its first experimental and clinical application of modern concept of Mg alloy development. We focused on biodegradable metal application in general surgery and orthopedic practice and showed the advantages and disadvantages Mg alloys offer. We focused on methods of in vitro and in vivo investigation of degradable Mg alloys and correlation between these methods. Based on the observed data, a better way for new alloy pre-clinical investigation is suggested. This review analyzes possible alloying elements that improve corrosion rate, mechanical properties, and gives the appropriate host response.

In vitro studies on silver implanted pure iron by metal vapor vacuum arc technique

Pure iron has been verified as a promising biodegradable metal for absorbable cardiovascular stent usage. However, the degradation rate of pure iron is too slow. To accelerate the degradation of the surface of pure iron, silver ions were implanted into pure iron by metal vapor vacuum arc (MEVVA) source at an extracted voltage of 40keV. The implanted influence was up to 2×10(17)ions/cm(2). The composition and depth profiles, corrosion behavior and biocompatibility of Ag ion implanted pure iron were investigated. The implantation depths of Ag was around 60nm. The element Ag existed as Ag2O in the outermost layer, then gradually transited to metal atoms in zero valent state with depth increase. The implantation of Ag ions accelerated the corrosion rate of pure iron matrix, and exhibited much more uniform corrosion behavior. For cytotoxicity assessment, the implantation of Ag ions slightly decreased the viability of all kinds of cell lines used in these tests. The hemolysis rate of Ag ion implanted pure iron was lower than 2%, which was acceptable, whereas the platelet adhesion tests indicated the implantation of Ag ions might increase the risk of thrombosis.

MiRNA-323-5p Promotes U373 Cell Apoptosis by Reducing IGF-1R

BACKGROUND MicroRNA regulates mammalian cell growth in terms of its proliferation and apoptosis by controlling the expression of target genes. MiRNA-323-5p plays an important role in regulating cell growth and death within various types of cells. The function of miRNA-323-5p and its possible molecular mechanism in human cerebral glioma U373 cells remains to be further confirmed. The aim of this study was to investigate the regulation function of miRNA-323-5p in human glioma U373 cell growth, proliferation, and apoptosis. MATERIAL AND METHODS We used human cerebral glioma U373 cells as the cell model; utilized liposome technology (transfected by Lipofectamine2000) in human cerebral glioma U373 cells to over-express miRNA-323-5p (microRNA used as control group); and selected MTT assay and flow cytometry to detect cell growth, proliferation, and apoptosis. We used RT-PCR and Western blotting techniques to study the expression levels of target insulin-like growth factor 1 (IGF-1) receptor protein in U373 cells transfected with miRNA-323-5p. We used liposome transfection techniques in human cerebral glioma U373 cells to over-express or processed knockdown of IGF-1R by siRNA, and then transferred with miRNA-323-5p, thereby investigating the treated human cerebral glioma U373 cells apoptosis situations. RESULTS The over-expression of miRNA-323-5p inhibited the growth and proliferation of human cerebral glioma U373 cells and promoted its apoptosis. The over-expression of miRNA-323-5p also reduced the IGF-1R level. After processing the knockdown of IGF-1R and then transfection with miRNA-323-5p, U373 cells had enhanced apoptosis. The over-expression of IGF-1R inhibited the cells apoptosis induced by miRNA-323-5p. CONCLUSIONS MiRNA-323-5p inhibited human cerebral glioma U373 cell proliferation and promoted its apoptosis by reducing IGF-1R.