QbD-driven development and characterization of superparamagnetic iron oxide nanoparticles (SPIONS) of a bone-targeting peptide for early detection of osteoporosis

Osteoporosis is a metabolic disorder that leads to deterioration of bones. The major challenges confronting osteoporosis therapy include early-stage detection and regular disease monitoring. The present studies employed D-aspartic acid octapeptide (-D-Asp-)8 as bone-targeting peptide for evaluating osteoporosis manifestation, and superparamagnetic iron oxide nanoparticles (SPIONs) as nanocarriers for MRI-aided diagnosis. Thermal decomposition technique was employed to synthesize SPIONs, followed by surface-functionalization with hydrophilic ligands. Failure mode effect analysis and factor screening studies were performed to identify concentrations of SPIONs and ligand as critical material attributes, and systematic optimization was subsequently conducted employing face-centered cubic design. The optimum formulation was delineated using desirability function, and design space demarcated with 178.70 nm as hydrodynamic particle size, -24.40 mV as zeta potential, and 99.89 % as hydrophilic iron content as critical quality attributes. XRD patterns ratified lattice structure and SQUID studies corroborated superparamagnetic properties of hydrophilic SPIONs. Bioconjugation of (-D-Asp-)8 with SPIONs (1:1) was confirmed using UV spectroscopy, FTIR and NMR studies. Cell line studies indicated successful targeting of SPIONs to MG-63 human osteoblasts, ratifying enormous bone-targeting and safety potential of peptide-tethered SPIONs as MRI probes. In vivo MRI imaging studies in rats showcased promising contrast ability and safety of peptide-conjugated SPIONs.

QbD-driven development of phospholipid-embedded lipidic nanocarriers of raloxifene: extensive in vitro and in vivo evaluation studies

Raloxifene (RLX) is popularly indicated in treatment of osteoporosis and prevention of breast cancer. Owing to its poor aqueous solubility, high pre-systemic metabolism, intestinal glucuronidation, and P-glycoprotein (P-gp) efflux, however, it demonstrates low (< 2%) and inconsistent oral bioavailability. The current work, Quality by Design (QbD)-driven development of phospholipid-embedded nanostructured lipidic carriers (NLCs) of RLX, accordingly, was undertaken to potentiate its lymphatic uptake, augment oral bioavailability, and possibly reduce drug dosage. Factor screening and failure mode effect analysis (FMEA) studies were performed to delineate high-risk factors using solid lipid (glyceryl monostearate), liquid lipid (vitamin E), and surfactant (Tween 80). Response surface optimization studies were performed employing the Box-Behnken design. Mathematical and graphical methods were adopted to embark upon the selection of optimized NLCs with various critical quality attributes (CQAs) of mean particle size as 186 nm, zeta potential of - 23.6 mV, entrapment efficiency of 80.09%, and cumulative drug release at 12 h of 83.87%. The DSC and FTIR studies, conducted on optimized NLCs, indicated successful entrapment of drug into the lipid matrix. In vitro drug release studies demonstrated Fickian diffusion mechanism. In vivo pharmacokinetic studies in rats construed significant improvement in AUC0-72 h (4.48-folds) and in Cmax (5.11-folds), unequivocally indicating markedly superior (p < 0.001) oral bioavailability of RLX-NLCs vis-à-vis marketed tablet formulation. Subsequently, level "A" in vitro/in vivo correlation (IVIVC) was also successfully attempted between the percentages of in vitro drug dissolved and of in vivo drug absorbed at the matching time points. In vitro cytotoxicity and cellular uptake studies also corroborated higher efficacy and successful localization of coumarin-6-loaded NLCs into MG-63 cells through microfluidic channels.

The Use of Nano-Hydroxyapatite (NH) for Socket Preservation: Communication of an Upcoming Multicenter Study with the Presentation of a Pilot Case Report

Background and Objectives: The use of biomaterials in dentistry is extremely common. From a commercial perspective, different types of osteoconductive and osteoinductive biomaterials are available to clinicians. In the field of osteoconductive materials, clinicians have biomaterials made of heterologous bones at their disposal, including biomaterials of bovine, porcine, and equine origins, and biomaterials of natural origin, such as corals and hydroxyapatites. In recent years, it has become possible to synthesize nano-Ha and produce scaffolds using digital information. Although a large variety of biomaterials has been produced, there is no scientific evidence that proves their absolute indispensability in terms of the preservation of postextraction sites or in the execution of guided bone regeneration. While there is no scientific evidence showing that one material is better than another, there is evidence suggesting that several products have better in situ permanence. This article describes a preliminary study to evaluate the histological results, ISQ values, and prevalence of nano-HA. Materials and Methods: In this study, we planned to use a new biomaterial based on nanohydroxyapatite for implantation at one postextraction site; the nano-HA in this study was NuvaBONE (Overmed, Buccinasco, Milano, Italy). This is a synthetic bone graft substitute that is based on nanostructured biomimetic hydroxyapatite for application in oral-maxillofacial surgery, orthopedics, traumatology, spine surgery, and neurosurgery. In our pilot case, a patient with a hopeless tooth underwent extraction, and the large defect remaining after the removal of the tooth was filled with nano-HA to restore the volume. Twelve months later, the patient was booked for implant surgery to replace the missing tooth. At the time of the surgery, a biopsy of the regenerated tissue was taken using a trephine of 4 mm in the inner side and 8 mm deep. Results: The histological results of the biopsy showed abundant bone formation, high values of ISQ increasing from the insertion to the prosthetic phase, and a good reorganization of hydroxyapatite granules during resorption. The implant is in good function, and the replaced tooth shows good esthetics. Conclusions: The good results of this pilot case indicate starting the next Multicentric study to have more and clearer information about this nanohydroxyapatite (NH) compared with control sites.

FT-IR analysis of the Interface between Universal Scotchbond and Oral Mucosa: a preliminary in-vitro study

BACKGROUND

The long-term success of implant therapy depends not only on proper osseointegration, but also on the healing of the epithelium and the quality of the biological seal on the abutment and on the implant neck. This study aims to evaluate the possible use of dentinal adhesives on the surface of the transmucosal path of dental implants in order to create a hermetic seal between keratinized epithelium and abutment.

METHODS

Four sections of 12 µm thickness were obtained from a sample of the oral mucosa. Scotchbond TM Universal Adhesive (3M ESPE, Seefeld, Germany) was carefully applied both to the samples and to the transmucosal path of titanium abutment (Win-Six, BioSAFin, Italy). The adhesives were polymerized. FT-IR analysis was performed on: 1) polymerized Scotchbond Universal Adhesive (3M ESPE, Seefeld, Germany); 2) the interface between the titanium abutment and the adhesive; 3) the interface between the adhesive and the mucosa; 4) the mucosa samples.

RESULTS

Comparing the spectra, it emerged that the adhesive has established chemical bonds both on titanium and on the keratinized mucosa, involving different types of chemical interactions.

CONCLUSIONS

The results of this in-vitro study are encouraging. In the future biocompatibility and comparative study with other adhesives will be required.

Human serum albumin-based nanoparticles alter raloxifene administration and improve bioavailability

Osteoporosis is a disease that reduces bone mass and microarchitecture, which makes bones fragile. Postmenopausal osteoporosis occurs due to estrogen deficiency. Raloxifene is a selective estrogen receptor modulator used to treat postmenopausal osteoporosis. However, it has a low bioavailability, which requires long-term, high-dose raloxifene administration to be effective and causes several side effects. Herein, raloxifene was encapsulated in human serum albumin (HSA)-based nanoparticles (Ral/HSA/PSS NPs) as an intravenous-injection pharmaceutical formulation to increase its bioavailability and reduce the treatment dosage and time. In vitro results indicated that raloxifene molecules were well distributed in HSA-based nanoparticles as an amorphous state, and the resulting raloxifene formulation was stabile during long-term storage duration. The Ral/HSA/PSS NPs were both biocompatible and hemocompatible with a decreased cytotoxicity of high-dose raloxifene. Moreover, the intravenous administration of the prepared Ral/HSA/PSS NPs to rats improved raloxifene bioavailability and improved its half-life in plasma. These raloxifene-loaded nanoparticles may be a potential nanomedicine candidate for treating postmenopausal osteoporosis with lower raloxifene dosages.

Epithelial Biological Response to Machined Titanium vs. PVD Zirconium-Coated Titanium: An In Vitro Study

The aim of this study was to compare the epithelial biological response to machined titanium Ti-6Al-4V grade 5 and titanium Ti-6Al-4V grade 5 coated with zirconia (ZrN) by physical vapor deposition (PVD). Human keratinocytes were cultured in six-well plates. Machined titanium TiAl4V4 grade 5 (T1) and ZrN-coated titanium TiAl4V4 grade 5 (T2) discs were placed in two different wells. The remaining two wells served as control (C). Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were performed to compare the T1 and T2 surfaces. Subsequent analyses were performed to explore the effect of T1 and T2 contact with human keratinocyte HUKE cell lines. Cell viability was evaluated using a trypan blue exclusion test and MTT assay. Cell lysates from C, T1, and T2 were Western blotted to evaluate E-cadherin and Integrin-α6β4 expression. SEM revealed that T2 was smoother and more homogeneous than T1. EDS showed homogeneous and uniform distribution of ZrN coating on T2. Cell viability analyses did not show significant differences between T1 and T2. Furthermore, E-cadherin and Integrin-α6β4 expressions of the epithelial cells cultured in T1 and T2 were similar. Therefore, titanium Ti-6Al-4V grade 5 surfaces coated with ZrN by PVD seem to be similar substrates to the uncoated surfaces for keratinocyte adhesion and proliferation.

Design and development of biomimetic electrospun sulphonated polyether ether ketone nanofibrous scaffold for bone tissue regeneration applications: in vitro and in vivo study

Bone defect restoration remains challenging in orthopedic medical practices. In this study an attempt is carried out to probe the use of new biomimetic SPEEK (sulfonated polyether ether ketone) based nanofibrous scaffold to deliver amine functionalized hydroxyapatite nanoparticles loaded resveratrol for its potent functionality in osteogenic differentiation. SPEEK polymer with reactive functional group SO₃H was synthesized through process of sulphonation reaction. Amine functionalized nanoparticles with protonated amino groups revamp the molecular interaction by the formation of hydrogen bonds that in turn intensify the bioactivity of the nanofibrous scaffold. Osteoconductive functionalized nanohydroxyapatite enhances the cell proliferation and osteogenicity with improved cell attachment and spreading. The results of FT-IR, XRD, Carbon-Silica NMR and EDX analysis confirmed the amine functionalization of the hydroxyapatite nanoparticles. Surface morphological analysis of the fabricated nanofibers through SEM and AFM analysis shows vastly interconnected porous structure that mimics the bone extracellular matrix, which enhances the cell compatibility. Cell adhesion and live dead assay of the nanoscaffolds express less cytotoxicity. Mineralization and alkaline phosphatase assay establish the osteogenic differentiation of the nanofibrous scaffold. The in vitro biocompatibility studies reveal that the fabricated scaffold was osteo-compatible with MG63 cell lines. Hemocompatibility study further proved that the designed biomimetic nanofibrous scaffold was highly suitable for bone tissue engineering. The results of in vivo analysis in zebrafish model for the fabricated nanofibers demonstrated significant increase in the caudal fin regeneration indicating mineralization of osteoblast. Thus, the commending results obtained instigate the potentiality of the composite nanofibrous scaffold as an effective biomimetic substrate for bone tissue regeneration.

Novel hydroxyapatite biomaterial covalently linked to raloxifene

Since raloxifene, a drug used in osteoporosis therapy, inhibits osteoclast, but not osteoblast functions, it has been suggested to improve recovery during implant surgery. The present paper describes an effective method to link raloxifene, through a covalent bond, to a nano-Hydroxyapatite-based biomaterial by interfacing with (3-aminopropyl)-Triethoxysilane as assessed by Infra Red-Fourier Transformed (IR-FT) spectroscopy and Scanning Electron Microscope (SEM). To evaluate the safety of this modified new material, the vitality of osteoblast-like cells cultured with the new biomaterial was then investigated. Raloxifene-conjugated HAbiomaterial has been shown to be a safe material easy to obtain which could be an interesting starting point for the use of a new functional biomaterial suitable in bone regeneration procedures.

Pre-Clinical Evaluation of a New Coral-Based Bone Scaffold

Coral is used worldwide for bone reconstruction. The favorable characteristics that make this material desirable for implantation are (i) osteoinduction, (ii) and osteoconduction. These proprieties have been demonstrated by in vivo studies with animal models and clinical trials over a twenty-year period. Also poly(2-hydroxyethylmethacrylate) [poly(HEMA)] is a widely used biomaterial. By using coral and poly(HEMA), a scaffold for bone reconstruction application has been recently synthesized. Cytological, histological and genetic analyses were performed to characterize this new alloplastic material. Four samples were analyzed: (a) white coral (WC), (b) red coral (RC), (c) WC plus polymer (WCP) and (d) RC plus polymer (RCP). Quantification of mitochondrial dehydrogenase activity by MTT assay was performed as indirect detector of cytotoxicity. In vivo effects were revealed by implanting corals and coral-based polymers in rabbit tibia. Samples were collected after 4 weeks and subjected to histological analysis. To evaluate the genetic response of cells to corals and coral-derived polymers an osteoblast-like cell line (i.e. MG63) was cultured in wells containing (a) medium, (b) medium plus corals and (c) medium plus two types of scaffolds (RCP or WCP). RNAs extracted from cells were retro-transcribed and hybridized on DNA 19.2K microarrays. No cytotoxicity was detected in corals and coral-based biopolymers. No inflammation or adverse effect was revealed by histological examination. By microarray analysis 154 clones were differentially expressed between RC and WC (81 up and 73 down regulated) whereas only 15 clones were repressed by the polymer. Histological evaluation not only confirmed that coral is a biocompatible material, but also that the polymer has no adverse effect. Microarray results were in agreement with cytological and histological analyses and provided further data regarding the genetic effects of RC, WC and the new polymer.