An aqueous method for the controlled manganese (Mn(2+)) substitution in superparamagnetic iron oxide nanoparticles for contrast enhancement in MRI.

Despite the success in the use of superparamagnetic iron oxide nanoparticles (SPION) for various scientific applications, its potential in biomedical fields has not been exploited to its full potential. In this context, an in situ substitution of Mn(2+) was performed in SPION and a series of ferrite particles, MnxFe1-xFe2O4 with a varying molar ratio of Mn(2+) : Fe(2+) where 'x' varies from 0-0.75. The ferrite particles obtained were further studied in MRI contrast applications and showed appreciable enhancement in their MRI contrast properties. Manganese substituted ferrite nanocrystals (MnIOs) were synthesized using a novel, one-step aqueous co-precipitation method based on the use of a combination of sodium hydroxide and trisodium citrate (TSC). This approach yielded the formation of highly crystalline, superparamagnetic MnIOs with good control over their size and bivalent Mn ion crystal substitution. The presence of a TSC hydrophilic layer on the surface facilitated easy dispersion of the materials in an aqueous media. Primary characterizations such as structural, chemical and magnetic properties demonstrated the successful formation of manganese substituted ferrite. More significantly, the MRI relaxivity of the MnIOs improved fourfold when compared to SPION crystals imparting high potential for use as an MRI contrast agent. Further, the cytocompatibility and blood compatibility evaluations demonstrated excellent cell morphological integrity even at high concentrations of nanoparticles supporting the non-toxic nature of nanoparticles. These results open new horizons for the design of biocompatible water dispersible ferrite nanoparticles with good relaxivity properties via a versatile and easily scalable co-precipitation route.

Hierarchically Porous Osteoinductive Poly(hydroxyethyl methacrylate-co-methyl methacrylate) Scaffold with Sustained Doxorubicin Delivery for Consolidated Osteosarcoma Treatment and Bone Defect Repair.

A bifronted cure system for osteosarcoma, a common aggressive bone tumor, is highly in demand to prevail the postsurgical adversities in connection with systemic chemotherapy and repair of critical-size bone defects. The hierarchically porous therapeutic scaffolds presented here are synthesized by free radical-initiated copolymerization of hydroxyethyl methacrylate and methyl methacrylate [HEMA/MMA 80:20 and 90:10 mM, H2O/NaCl porogen], which are further surface-phosphorylated [P-PHM] and transformed to bifunctional by impregnating doxorubicin (DOX) [DOXP-PHM]. The P-PHM scaffolds exhibited porous microarchitecture analogous to native cancellous bone (scanning electron microscopy analysis), while X-ray photoelectron spectroscopy analysis authenticated surface phosphorylation. Based on pore characteristics, swelling attributes and slow-pace degradation, P-PHM9163 and P-PHM8263 (HEMA/MMA 90:10 and 80:20 with H2O/NaCl: 60/3.0 weight %, respectively) were chosen from the series and evaluated for osteoinductive efficacy in vitro. Both P-PHM9163 and P-PHM8263 invoked calcium phosphate mineralization in simulated physiological conditions (day 14) with Ca/P ratios of 1.58 and 1.66 respectively, comparable to human bone (1.67). Early biomineralization (Alizarin Red S and von Kossa staining) was evidenced at day 7, while osteoblast differentiation was verified by time-dependent expression of the typical late marker, osteocalcin, at day 14 and 21 in rat bone marrow mesenchymal cells. DOX-loaded P-PHM9163 (DOXP-PHM9163) exhibited pH-responsive (tumor analogous pH; 6.5) sustained release of DOX for prolonged time (up to 45 days) and invoked cellular alterations by cortical stress fiber formation and DNA fragmentation in human osteosarcoma cells leading to early apoptosis (24 h), validated by annexin V/PI staining (FACS) and immunostaining (F-actin/DAPI). Subsequent to DOX release tenure, the scaffold induced the formation of well-organized, porous post-release Ca-P apatite coating (Ca/P is 1.3) in simulated body fluid (day 14) which further endorses the dual functionality of the system. Altogether, the results accentuate that DOXP-PHM9163 is a potential bifunctional therapeutic scaffold capable of extended localized chemotherapeutic delivery in-line with inherent osteogenesis for efficient bone cancer treatment.

Utility of Chitra-HASi Granules in Cystic Defects of the Maxillofacial Region: A Pilot Study.

BACKGROUND: Cystic defects that are critical sized or larger require bone replacement strategies. However, due to inherent disadvantages of the various types of grafts, none of the available materials are best suited for these defects. Among the alloplastic materials, hydroxyapatite (HA)-based grafts are the most popular, due to their osteoconductive nature and resemblance to mineral bone. The aim of the study was to assess the utility of the novel material "Chitra-HASi" as a bone substitute in the maxillofacial region. MATERIALS AND METHODS: In a single-arm, prospective study, patients with radicular and dentigerous cysts were included and the minimum defect size was standardized at 20 × 20 mm or above. The Chitra-HASi material was developed by a wet precipitation technique and adopted for use following multiple in vitro and in vivo studies, confirming its safety and biocompatibility profile. All cysts underwent enucleation, followed by peripheral ostectomy and apicectomy of the teeth involved. The HASi graft was packed inside the cystic defect in a granular form and covered with a mucoperiosteal flap. Panoramic radiographs were taken preoperatively and at 3, 6, and 12 months postoperatively. RESULTS: Twenty-three patients were included in the study, of which only 10 patients could be followed up for 12 months after graft placement. The mean preoperative bone density was found to be 14.9% ± 4.97 (standard deviation), whereas the postoperative 3-month, 6-month, and 12-month densities had a mean difference of -11.3%, -22.9%, and -37.3%, respectively, and the differences were statistically significant. Minor complications such as sinus formation (n = 7) and extrusion of granules (n = 4) were noted, which were managed conservatively. Only two patients required graft removal secondary to infection, leading to a persistent sinus tract. CONCLUSION: The results of the study suggest that Chitra-HASi granules show potential as an alternative to other bone substitutes. The addition of silica to the porous HA material offers superior strength characteristics and needs long-term evaluation to assess its stability in large cystic defects.

Asialoglycoprotein receptor targeted optical and magnetic resonance imaging and therapy of liver fibrosis using pullulan stabilized multi-functional iron oxide nanoprobe.

Early diagnosis and therapy of liver fibrosis is of utmost importance, especially considering the increased incidence of alcoholic and non-alcoholic liver syndromes. In this work, a systematic study is reported to develop a dual function and biocompatible nanoprobe for liver specific diagnostic and therapeutic applications. A polysaccharide polymer, pullulan stabilized iron oxide nanoparticle (P-SPIONs) enabled high liver specificity via asialogycoprotein receptor mediation. Longitudinal and transverse magnetic relaxation rates of 2.15 and 146.91 mM-1 s-1 respectively and a size of 12 nm, confirmed the T2 weighted magnetic resonance imaging (MRI) efficacy of P-SPIONs. A current of 400A on 5 mg/ml of P-SPIONs raised the temperature above 50 °C, to facilitate effective hyperthermia. Finally, a NIR dye conjugation facilitated targeted dual imaging in liver fibrosis models, in vivo, with favourable histopathological results and recommends its use in early stage diagnosis using MRI and optical imaging, and subsequent therapy using hyperthermia.

Surface-transformed osteoinductive polyethylene terephthalate scaffold as a dual system for bone tissue regeneration with localized antibiotic delivery.

Multifunctional scaffolds have recently attained superior significance in tissue regeneration due to combinational activity profile that is usually accomplished by separate sequential therapy. Here, we present a dual system comprised of surface-phosphorylated PET fibrous matrix coated with ciprofloxacin-impregnated biodegradable polymer poly (hydroxyethyl methacrylate) aiming at regeneration of bone tissue deprived of bacterial infections, particularly osteomyelitis. The ATR, XPS and FESEM/EDX results provided confirmative evidences for surface phosphorylation of PET and in situ coating of the polymer. Swelling and contact angle measurements demonstrated improved hydrophilicity which is further corroborated by in vitro degradation profile in PBS. Preliminary evaluation by MTT and actin staining proved its biocompatibility while enhanced in vitro mineralization in 1.5X SBF by FESEM/EDX clearly indicate the primary nucleation and secondary growth of beautiful apatite crystals with Ca/P ratio similar to human bone. Alizarin red S and von Kossa staining validated the biomineralization in MG-63 cells. The sequential expression of early and late biomarkers -alkaline phosphatase (ALP) and osteocalcin (OSN)- of osteoblast differentiation in rat bone marrow mesenchymal cells (BMC) has demonstrated osteoinductive nature of the system. The second functionality of the scaffold has been proven by step-wise ciprofloxacin-release profile (in vitro) with ~60% release within 120 h. In addition, antibacterial studies of ciprofloxacin- eluted from the scaffold have shown apparent zones of inhibition against Staphylococcus aureus (3.6 ± 0.3 cm) and Escherichia coli (3.0 ± 0.8 cm). Hence, the surface-transformed PET scaffold function as a dual system as localized antibiotic delivery vehicle against bone infections and undergo self-biomineralization leading to osteoinduction.

Self-Controlled Hyperthermia & MRI Contrast Enhancement via Iron Oxide Embedded Hydroxyapatite Superparamagnetic particles for Theranostic Application.

Increasing effectiveness of cancer therapeutics requires a multipronged approach. Delivery of controlled hyperthermia in the ranges of 43 to 45 °C on site aided by superparamagnetic particles ensures cell death via the apoptosis pathway.We demonstrated the use of iron-oxide embedded hydroxyapatite (HAIO) superparamagnetic particles for delivery of controlled hyperthermia and contrast enhancement in MRI. To determine optimal hyperthermia delivery, we used 5 and 10 mg/mL concentrations of HAIO on various magnetic fields in alternating magnetic field (AMF) study. Time-temperature profile and specific loss power (SLP) data revealed that HAIO delivered precisely controlled temperature in contrast to superparamagnetic iron oxide nanoparticles (SPIONs). Earlier studies had demonstrated that HAIO concentrations of 0.5 to 3 mg/mL are cytocompatible. Exposure of HeLa cells to HAIO at a concentration of 2 mg/mL and applied field of 33.8 mT for a period of 30 min resulted in apoptosis induction in 75% of population. Significant cellular disruption was affirmed via FACS, ESEM and cLSM techniques. An aqueous phantom study and in vitro cell culture study evaluation indicated relaxivity of 50.92 mM-1 s-1 and good pixel intensity variation in MRI. The current study assesses the potential of HAIO to deliver controlled hyperthermia and act as a negative MRI contrast agent. Repeated experiments have confirmed enhanced utility of the technique in the burgeoning field of theranostics.

Multifunctional nano manganese ferrite ferrofluid for efficient theranostic application.

Ferrofluid-based manganese (Mn(2+)) substituted superparamagnetic iron oxide nanoparticles stabilized by surface coating with trisodium citrate (MnIOTCs) were synthesized for enhanced hyperthermic activity and use as negative magnetic resonance imaging (MRI) contrast media intended for applications in theranostics. The synthesized MnIOTC materials were characterized based on their physicochemical and biological features. The crystal size and the particle size at the nano level were studied using XRD and TEM. The presence of citrate molecules on the crystal surface of the iron oxide was established by FTIR, TGA, DLS and zeta potential measurements. The superparamagnetic property of MnIOTCs was measured using a vibrating sample magnetometer. Superparamagnetic iron oxide substituted with Mn(2+) with a 3:1 molar concentration of Mn(2+) to Fe(2+) and surface modified with trisodium citrate (MnIO75TC) that exhibited a high T2 relaxivity of 184.6mM(-1)s(-1) and showed excellent signal intensity variation in vitro. Hyperthermia via application of an alternating magnetic field to MnIO75TC in a HeLa cell population induced apoptosis, which was further confirmed by FACS and cLSM observations. The morphological features of the cells were highly disrupted after the hyperthermia experiment, as evidenced from E-SEM images. Biocompatibility evaluation was performed using an alamar blue assay and hemolysis studies, and the results indicated good cytocompatibility and hemocompatibility for the synthesized particles. In the current study, the potential of MnIO75TC as a negative MRI contrast agent and a hyperthermia agent was demonstrated to confirm its utility in the burgeoning field of theranostics.

Citrate coated iron oxide nanoparticles with enhanced relaxivity for in vivo magnetic resonance imaging of liver fibrosis.

Superparamagnetic iron oxide nanoparticles are widely used for the magnetic resonance imaging (MRI) applications. The surface characteristics, magnetic properties, size and targeting efficiency of the material are crucial factors for using the same as contrast agents. We report a simple synthesis method of citrate coated iron oxide nanoparticles and its systematic characterization. The developed system is highly water dispersible with an average particle size of 12 nm. The particles in water are monodisperse and are found to be stable over long periods. The efficiency of the material to de-phase water proton has been studied for various concentrations of iron using longitudinal (T1) and transverse (T2) weighted MRI. The coating thickness of the nanoparticle was optimized so that they exhibited a high transverse to longitudinal relaxivity (r2/r1) ratio of 37.92. A clear dose-dependent contrast enhancement was observed in T2 weighted in vivo MR imaging of liver fibrosis model in rodents. The labelling efficacy of the particle and the intracellular magnetic relaxivity were also investigated and presented. The particles were also tested for blood and cellular compatibility studies. Development of fibrosis and presence of iron in the liver was confirmed by histopathological analysis. From this study, we conclude that the citrate coated ultra small superparamagnetic iron oxide nanoparticles (C-USPION) with optimized parameters like particle size and magnetic property are capable of producing good MR contrast in imaging of liver diseases.

Periapical tissue reaction to calcium phosphate root canal sealer in porcine model.

BACKGROUND: Calcium phosphate cements (CPC) are a group of biomaterials possessing wide scope of use in various branches of medical science. These materials have been proposed to be highly biocompatible and osteoconductive. This study is based on a newly developed CPC formulation (Chitra-CPC) and is aimed at the evaluation of its biocompatibility through an Endodontic Usage Test in a porcine study model. OBJECTIVE: To evaluate the periapical tissue reaction to Chitra-CPC when used as a root canal sealer/filler material in comparison with a resin sealer, AH Plus (Dentsply). MATERIALS AND METHODS: The procedure was done on porcine animal model following the ISO 7405 criteria. The material was implanted intentionally into the periapical area of 36 teeth through a root canal procedure carried out in six animals which were divided equally among 1-month and 3-month time periods. Results were based on the histological evaluation of the autopsied specimens after the prescribed time periods. RESULTS: Mild to moderate periapical tissue reaction was found in Chitra-CPC samples belonging to the 1-month time period, whereas majority of the 3-month CPC samples showed an absence of inflammation. Samples of AH Plus in 1-month period showed severe to moderate inflammation, whereas 3-month AH Plus samples had a mild to moderate inflammation. CONCLUSIONS: Chitra-CPC is a biocompatible material.