This paper presents the computational assessment of the electrochemical stability of a series of alkyl methylimidazolium-based ionic liquids for their use as lithium battery electrolytes. The oxidation and reduction potentials of the constituent cation and anion of each ionic liquid with respect to a Li(+)/Li reference electrode were calculated using density functional theory following the method of thermodynamic cycles, and the electrochemical stability windows (ESW)s of these ionic liquids were obtained. The effect of varying the length of alkyl side chains of the methylimidazolium-based cations on the redox potentials and ESWs was investigated. The results show that the limits of the ESWs of these methylimidazolium-based ionic liquids are defined by the oxidation potential of the anions and the reduction potential of alkyl-methylimidazolium cations. Moreover, ionic liquids with [PF6](-) anion have a wider ESW. In addition to characterizing structure-function relationships, the accuracy of the computational approach was assessed through comparisons of the data against experimental measurements of ESWs. The potentials calculated by the thermodynamic cycle method are in good agreement with the experimental data while the HOMO/LUMO method overestimates the redox potentials. This work demonstrates that these approaches can provide guidance in selecting ionic liquid electrolytes when designing high-voltage rechargeable batteries.

Poly(ethylene glycol) (PEG) is the most widely used polymer in delivering anticancer drugs clinically. PEGylation (i.e., the covalent attachment of PEG) of peptides proteins, drugs, and bioactives is known to enhance the aqueous solubility of hydrophobic drugs, prolong circulation time, minimize nonspecific uptake, and achieve specific tumor targetability through the enhanced permeability and retention effect. Numerous PEG-based therapeutics have been developed, and several have received market approval. A vast amount of clinical experience has been gained which has helped to design PEG prodrug conjugates with improved therapeutic efficacy and reduced systemic toxicity. However, more efforts in designing PEG-based prodrug conjugates are anticipated. In light of this, the current paper highlights the synthetic advances in PEG prodrug conjugation methodologies with varied bioactive components of clinical relevance. In addition, this paper discusses FDA-approved PEGylated delivery systems, their intended clinical applications, and formulations under clinical trials.

Recently, tantalum is gaining more attention as a new metallic biomaterial as it has been shown to be bioactive and biologically bond to the bone. However, relatively high cost of manufacture and inability to produce a modular all tantalum implant has limited'its widespread acceptance. In this study, we have successfully deposited Ta coating on Ti using Laser Engineered Net Shaping (LENS™) to enhance osseointegration properties. In vitro biocompatibility study, using human osteoblast cell line hFOB, showed excellent cellular adherence and growth with abundant extracellular matrix formation on Ta coating surface compare to Ti surface. Six times higher living cell density was observed on Ta coating than on Ti control surface during MMT assay. High surface energy and wettability of Ta surface were observed to contribute to its significantly better cellmaterials interactions. Also, these dense Ta coatings do not suffer from low fatigue resistance due to the absence of porosity and sharp interface between the coating and the substrate, which is a major concern for porous coatings used for enhanced/early biological fixation.

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The aim of this work is to evaluate the influence of MgO, SrO and SiO2 doping on mechanical and biological properties of β-tricalcium phosphate (β-TCP) to achieve controlled resorption kinetics of β-TCP system for maxillofacial and spinal fusion application. We prepared dense TCP compacts of four different compositions, i) pure β-TCP, ii) β-TCP with 1.0 wt. % MgO + 1.0 wt. % SrO, iii) β-TCP with 1.0 wt. % SrO + 0.5 wt. % SiO2, and iv) β-TCP with 1.0 wt. % MgO + 1.0 wt. % SrO + 0.5 wt. % SiO2, by uniaxial pressing and sintering at 1250 °C. β phase stability is observed at 1250 °C sintering temperature due to MgO doping in β-TCP. In vitro mineralization in simulated body fluid (SBF) for 16 weeks shows excellent apatite growth on undoped and doped samples. Strength degradation of TCP samples in SBF is significantly influenced by both dopant chemistry and amount of dopant. Compressive strengths for all samples show degradation in SBF over the 16 week time period with varying degradation kinetics. MgO/SrO/SiO2 doped sample shows no strength loss, while undoped TCP shows the maximum strength loss from 419 ±28 MPa to 158 ±28 MPa over the 16 week study. In case of MgO/SrO doped TCP, strength loss is slow and gradual. TCP doped with 1.0 wt. % MgO and 1.0 wt. % SrO shows excellent in vivo biocompatibility when tested in male Sprague-Dawley rats for 16 weeks. Histomorphology analysis reveals that MgO/SrO doped TCP promoted osteogenesis by excellent early stage bone remodeling as compared to undoped TCP.

Bovine serum albumin (BSA) protein incorporated with hydroxyapatite (HA) nanoparticles (NPs) were synthesized by in situ precipitation process. 2 mol% Zn 2+ and Mg 2+ were used as dopants to synthesize Zn 2+ /Mg 2+ doped HA-BSA NPs by in situ synthesis route. In our study we used BSA as a model protein. The amount of BSA uptake by doped and undoped HA NPs and subsequent release of BSA from NPs were investigated. Zn doped HA NPs showed the highest amount of BSA uptake, whereas the amount of BSA loaded in undoped HA NPs was the lowest. A two-stage BSA release profile from doped and undoped HA NPs was observed in phosphate buffer solution (PBS) at pH 7.2 ± 0.2. Initial burst release was due to the desorption of BSA from the HA surface. The later stage of slow release was controlled by the dissolution of BSA incorporated HA NPs. BSA release rate from Zn doped HA NPs was found to be the highest, whereas undoped HA NPs released BSA at the slowest rate. Our study showed that the protein release rate from HA NPs can be controlled by the addition of suitable dopants and doped HA based NP systems can be used in bone growth factor and drug release study. KeywordsNanoparticles; Hydroxyapatite; Dopant; Bovine serum albumin; Protein release IntroductionIn the recent years there has been increasing interest in inorganic nanoparticles (NPs) as carriers for macromolecules such as proteins, vaccines, and drugs. Numerous studies have shown that NPs can not only improve the resistance of therapeutic agents against enzymatic degradation, but also provide the possibility of transporting biomolecules to specific tissues, cells, and cell compartments in a controlled manner with a minimal invasive procedure. [1,3] Inorganic NPs have some potential advantages over other polymeric nanoparticulate based carrier systems, because of their low susceptibility to immune response as compared to viral vectors, low toxicity as opposed to organic NPs, and resistance to lipases and bile salts unlike liposomes.Among the inorganic NPs, hydroxyapatite (HA) has attracted much attention as a carrier for biomolecules because of its excellent biocompatibility and bioactivity. For orthopedic applications, porous HA-based implants infiltrated with bioactive agents or drugs have been reported. [4][5] However, limited surface area and unpredictable bioresorbability of HA implant have been the issues that remain to be resolved for the development of a controlled drug carrier system. In the past decade, these problems have been addressed in some research efforts directed towards the synthesis of HA micro or nano-carriers delivering antibiotics and growth factors with controlled release kinetics. Jntema et al. employed HA microcrystals as microcarriers to load bovine serum albumin (BSA) of 5-10 wt.% and concluded that these can NIH Public Access After washing, all the powders were dried at room temperature and stored in a freezer at −10°C.All the supernatants after every washing were collected and analyzed for concentration of BSA using a BCA protein assa...

A novel magnetic nanocarrier, cyclodextrin (CD)−citrate−gum arabic modified magnetic nanoparticles (GAMNPs), for hydrophobic drug delivery was fabricated by grafting the citrate-modified CD onto the GAMNPs via carbodiimide activation. The analyses of the transmission electron microscopy and the dynamic light scattering revealed that the product had a mean diameter of 14.6 nm and a mean hydrodynamic diameter of 26.2 nm. The CD grafting was confirmed by Fourier transform infrared spectroscopy, and the amount of CD grafted on the GAMNPs was determined to be 28.7 mg/g by the thermogravimetric analysis. The feasibility of using CD−citrate−GAMNPs as a carrier for hydrophobic drug delivery was demonstrated by investigating the formation of the inclusion complex and the in vitro release profile using ketoprofen as a model hydrophobic drug. It was found that CD−citrate−GAMNPs exhibited a considerable adsorption capability for ketoprofen as compared to GAMNPs. The complexation of CD−citrate−GAMNPs with ketoprofen was found to be exothermic and follow the Langmuir adsorption isotherm. Also, the presence of surfactant (sodium dodecyl sulfate, SDS) led to a decrease in the inclusion of ketoprofen because the linear structure of SDS made it easier to enter the cavity of CD as compared with the less linear ketoprofen. The results of the ketoprofen inclusion and the release experiments indicate that this system seems to be a very promising vehicle for the administration of hydrophobic drugs.