pH Responsive Bioactive Lead Sulfide Nanomaterials: Protein Induced Morphology Control, Bioapplicability, and Bioextraction of Nanomaterials

Precise morphologies of pH responsive bioactive lead sulfide nanoparticles (PbS NPs) were synthesized by using industrially and environmentally important proteins like zein and lysozyme (Lys), and a bioactive polymer diethylaminoethyl dextran chloride (DEAE). Though, proteins are not known morphology control agents, zein demonstrated a fine crystal growth control of PbS NPs better than Lys as well as DEAE, and even better than conventional surfactants known for their shape control behavior. Proteins and DEAE coated NPs thus obtained were highly pH responsive in terms of a color change from light gray (at low pH) to dark brown (at high pH). Bioapplicability of coated NPs was done by subjecting them to hemolysis. Both Lys and DEAE coated NPs did not induce any significant hemolysis and demonstrated their good compatibility and usability in systemic circulation. For their industrial scale uses, different extraction methods were proposed by using other industrially important biomolecules and ionic liquids. Alginic acid and xanthan gum were excellent complexing agents for an instant extraction of Lys and DEAE coated NPs from aqueous phase. Ionic liquid exhibited excellent extraction ability in both organic as well as aqueous phases

Ecofriendly Route To Synthesize Nanomaterials for Biomedical Applications: Bioactive Polymers on Shape-Controlled Effects of Nanomaterials under Different Reaction Conditions

Bioactive diethylaminoethyl dextran chloride (DEAE-D), a versatile polymer with numerous industrial applications, was used as a shape-directing agent for the synthesis of gold (Au) nanoparticles (NPs) in a typical green chemistry synthetic route. Shape-controlled growth was precisely directed by the quaternary amine functionalities of DEAE-D, while its polycationic nature provided simultaneous colloidal stabilization. Mechanistic aspects were drawn from different sets of reactions in which DEAE-D was directly used as a reducing agent with respect to reaction time and temperature. All reactions were simultaneously monitored with UV–visible studies, and NPs were characterized by TEM, SEM, and AFM analysis. Shape-controlled synthesis produced large extraordinarily thin microplates that were converted into small spherical NPs simply by switching the reaction to seed-growth (S-G) mode. DEAE-D-coated NPs thus produced were subjected to hemolysis for their possible use as drug release vehicles in systemic circulation so as to explore their possible biomedical applications

Block Copolymer Micelles as Nanoreactors for Self-Assembled Morphologies of Gold Nanoparticles

Self-assembled gold (Au) nanoparticles (NPs) were synthesized in micelle surface cavities of a L121 block polymer in the presence of zwitterionic (viz. DPS, TPS, and HPS) and sugar surfactants (OG and DDM) in aqueous phase at 70 °C by using the surface cavities of L121 as reducing sites for converting Au­(III) into Au(0). All reactions were monitored simultaneously by UV–visible spectroscopy to determine the growth kinetics in gold nucleating centers on the basis of surface plasmon resonance that also helped in tracing the structure micelle transitions over a wide temperature range of 10–70 °C. The surfactant/L121 mole ratio was changed systematically from 0.5 to 2.5 by keeping L121 and HAuCl₄ concentrations constant at 10 and 0.25 mM, respectively, to determine the shape and size of the micelles and their relation to the self-assembled behavior of Au NPs. TEM studies were used to have a direct insight into the morphology of micelle templates and their shape and size for self-assembled NPs. L121 along with DPS (C12 carbon chain) produced well-defined micelles loaded with tiny NPs of 3–6 nm in the L121-rich region of the mixture, while large flower-like compound micelles with a clear core–shell morphology were produced in the DPS-rich region. TPS and HPS (C14 and C16 hydrocarbon chains, respectively) with stronger hydrophobicity than DPS also produced almost similar micelles loaded with tiny NPs in the L121-rich region, but they disappear in the surfactant-rich region. Replacement of zwitterionic with ionic surfactants did not yield micelle templates for self-assembled NPs. Results conclude that well-defined micelles of L121 are the fine templates for self-assembled NPs that can only be achieved in the presence of a neutral surfactant with low concentration and low hydrophobicity

Bipyridinium and Imidazolium Ionic Liquids for Nanomaterials Synthesis: pH Effect, Phase Transfer Behavior, and Protein Extraction

We demonstrate the potential use of 1,1′-<i>bis</i>(2-(cyclo­hexyloxy)-2-oxoethyl)-[4,4′-bipyridin]-1,1′-diium bromide (BP) and 1-ethyl-3-methyl­imidazolium chloride (EMI) ionic liquids (ILs) in in situ synthesis of gold nanoparticles (Au NPs) without using any external reducing or stabilizing agents. Both ILs produced nearly monodisperse NPs of 4–8 nm which were present in the form of self-assembled states. BP coated NPs formed self-assembled sheets and easily transferred to the organic phase by employing the water insoluble IL as a phase transfer agent. The efficiency of the phase transfer process was related to the extent of aggregation as well as functional groups. Both IL coated NPs were further used to extract the proteins from the complex biological mixtures. EMI coated NPs extracted proteins of large molar masses whereas BP coated NPs were good for the extraction of low molecular mass proteins. This disparity was controlled by the substituted functional groups of ILs. Bulky cyclohexyloxy functional groups of BP did not allow extraction of large molar mass proteins. Such a wide applicability of ILs in nanomaterials synthesis opens several new applications in the field of nanomedicine and nanobiotechnology where IL coated NPs can be used for diverse protein complexation

Lymphomatoid granulomatosis in a pediatric patient.

We report the radiology and pathology of a pediatric patient with lymphomatoid granulomatosis (LG) and review the literature, with an emphasis on the radiological findings and on the small subset of pediatric patients with this rare condition

A rare mutation in lamin A gene is associated with dilated cardiomyopathy in Indian patients

Mutations in lamin A gene (LMNA) are associated with a number of genetic diseases that are collectively termed laminopathies. Most LMNA mutations cause muscular dystrophies and cardiomyopathies. The incidence of LMNA mutations in familial dilated cardiomyopathy (DCM) patients is 5-8 % in Caucasian populations. However, there is no large scale study of LMNA mutations in Indian DCM patients. Hence, we have carried out sequence analysis of LMNA in 239 Indian DCM patients. We have identified a rare non-synonymous mutation c.1873A&#62;T in one patient, which predicted a change in the amino acid serine to cysteine at residue 625. In addition we also identified 20 synonymous single nucleotide polymorphisms in 28 patients. The c.1873A&#62;T mutation was absent in 156 healthy and ethnically matched controls. The serine at position 625 has been earlier identified as a mitotic phosphorylation site in lamin A. Expression of mutant lamin S625C in cultured cells led to a decrease in levels of cyclin dependent kinase inhibitor p21, suggesting compromised cell cycle regulation in these cells. Our study provides important information on the extent of variations in LMNA in Indian DCM patients and identifies a rare mutation in LMNA that is likely to cause deleterious effects on cellular functions

Green Chemistry of Zein Protein Toward the Synthesis of Bioconjugated Nanoparticles: Understanding Unfolding, Fusogenic Behavior, and Hemolysis

Green chemistry of industrially important zein protein was explored in aqueous phase toward the synthesis of bioconjugated gold (Au) nanoparticles (NPs), which allowed us to simultaneously understand the unfolding behavior of zein with respect to temperature and time. Synthesis of Au NPs was monitored with simultaneous measurements of UV–visible absorbance due to the surface plasmon resonance (SPR) of Au NPs that triggered the adsorption of zein on the NP surface and thus resulted in its unfolding. Surface adsorption of zein further controlled the crystal growth of Au NPs, which relied on the degree of unfolding and fusogenic behavior of zein due to its predominant hydrophobic nature. The latter property induced a marked blue shift in the SPR rarely observed in the growing NPs during the nucleation process. A greater unfolding of zein in fact was instrumental in generating zein-coated faceted NPs that were subjected to their hemolytic response for their possible use as drug release vehicles. Zein coating significantly reduced the hemolysis and made bioconjugated Au NPs the best models for biomedical applications in nanotechnology