Jui Chakraborty

Mg-Al layered double hydroxide-methotrexate nanohybrid drug delivery system: evaluation of efficacy.

Mg-Al layered double hydroxide nanoparticles were synthesized by one-pot co-precipitation method and anticancerous drug methotrexate was incorporated into it by in-situ ion exchange. The LDH-MTX nanohybrid produced moderately stable suspension in water, as predicted by zeta potential measurement. X-ray diffraction revealed that the basal spacing increased to nearly twice the same for pristine LDH on MTX intercalation. Thermogravimetric analyses confirmed an increase in thermal stability of the intercalated drug in the LDH framework. A striking enhancement in efficacy/sensitivity of MTX on the HCT-116 cells was obtained when intercalated within the LDH layers, as revealed by the attainment of half maximal inhibitory concentration of LDH-MTX nanohybrid by 48 h, whereas, bare MTX required 72 h for the same. The MTX release from MgAl-LDH-MTX hybrids in phosphate buffer saline at pH7.4 followed a relatively slow, first order kinetics and was complete within 8 days following diffusion and crystal dissolution mechanism.

siRNA-nanoparticle conjugate in gene silencing: A future cure to deadly diseases?

Alzheimers, cancer, acquired immune deficiency syndrome (AIDS) are considered to be some of the most deadly diseases of the 21st century on account of their severity and rapid increase in the number of affected population and with scarce cases of recovery, they still remain a troubling paradox. Specifically, with millions of cancer patients worldwide and lack of proper cure for the same, understanding the deadly disease at the molecular level and planning a therapeutic strategy in the same line is the need of the hour. Further, the potential threat of prevalence and escalation of Alzheimers and HIV (human immunodeficiency virus) infection by more than three times as of recent past, needs a medical breakthrough to arrive at a meaningful solution to tackle the present day scenario. It is evident that these diseases initiate and propagate based on certain genes and their expression which needs to be silenced by the help of small interfering RNA (siRNA) by at least 70%. For short term silencing of the protein coding genes, siRNA is the most appropriate tool. Hence, the present communication explores the possibility for treatment and cure of a plethora of deadly diseases, e.g., cancer, including Alzheimers and AIDS to some extent, emphatically at the molecular level, using the current trend of RNAi (RNA interference) delivery via a wide variety of nanoparticles.

Layered Double Hydroxides Based Ceramic Nanocapsules as Reservoir and Carrier of Functional Anions

An extensive study of the intercalation of a number of commercially important anions into a range of layered double hydroxides (LDHs) has been presented. Intercalating anions include key drugs, vitamins, fragrances, dye, etc. The immense potential of LDH systems as reservoirs and carrier of different functional anions was demonstrated. The release of the guest anions was studied in representative conditions.

Effect of Process Variations on Anticancerous Drug Intercalation in Ceramic Based Delivery System

Two methods have been attempted to intercalate an anionic anticancerous drug methotrexate (MTX) into Mg-Al layered double hydroxide (LDH): a) anion exchange method (sample A′) and b) in situ coprecipitation method followed by a soft hydrothermal treatment (sample A″) to form a biohybrid material. Both the materials obtained were characterized by powdered sample X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), thermogravimetric-differential thermal analysis (TG-DTA), particle size distribution (PSD) analysis and field emission scanning electron microscopy (FE-SEM). High performance liquid chromatography (HPLC) was used to determine the integrity of the MTX and to quantify the drug loading in the materials. HPLC data of sample A′ confirms the integrity of the MTX moiety in the interlayer space of Mg-Al-LDH which has been further verified by XRD and FTIR spectroscopy and drug loading in the hybrid system was found to be 20.22 mg.g−1. However, the HPLC data of sample A″ supports that under soft hydrothermal condition decomposition of MTX is operating and the major decomposition product was identified as N10-methyl folic acid that remains adsorbed on Mg-Al-LDH surface, primarily, as indicated by the TG-DTA study.

Self-assembled structures of hydroxyapatite in the biomimetic coating on a bioinert ceramic substrate

The tribological properties of alumina ceramic are excellent due in part to a high wettability because of the hydrophilic surface and fluid film lubrication that minimizes the adhesive wear. Such surfaces are further modified with bioactive glass/ceramic coating to promote direct bone apposition in orthopedic applications. The present communication reports the biomimetic coating of calcium hydroxyapatite (HAp) on dense (2-3% porosity) alumina (alpha-Al(2)O(3)) substrate (1cm x 1cm x 0.5 cm), at 37 degrees C. After a total period of 6 days immersion in simulated body fluid (SBF), at 37 degrees C, linear self-assembled porous (pore size: approximately 0.2 microm) structures (length: approximately 375.39 microm and width: 5-6 microm) of HAp were obtained. The phenomenon has been demonstrated by self-assembly and diffusion-limited aggregation (DLA) principles. Structural and compositional characterization of the coating was carried out using SEM with EDX facility, XRD and FT-IR data.

Comparative assessment of structural and biological properties of biomimetically coated hydroxyapatite on alumina (α-Al2O3) and titanium (Ti-6Al-4V) alloy substrates

Previous reports have shown the use of hydroxyapatite (HAp) and related calcium phosphate coatings on metal and nonmetal substrates for preparing tissue-engineering scaffolds, especially for osteogenic differentiation. These studies have revealed that the structural properties of coated substrates are dependent significantly on the method and conditions used for coating and also whether the substrates had been modified prior to the coating. In this article, we have done a comparative evaluation of the structural features of the HAp coatings, prepared by using simulated body fluid (SBF) at 25 degrees C for various time periods, on a nonporous metal substrate titanium-aluminium-vanadium (Ti-6Al-4V) alloy and a bioinert ceramic substrate alpha-alumina (alpha-Al(2)O(3)), with and without their prior treatment with the globular protein bovine serum albumin (BSA). Our analysis of these substrates by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry showed significant and consistent differences in the quantitative and qualitative properties of the coatings. Interestingly, the bioactivity of these substrates in terms of supporting in vitro cell adhesion and spreading, and in vivo effects of implanted substrates, showed a predictable pattern, thus indicating that some coated substrates prepared under our conditions could be more suitable for biological/biomedical applications.

Drug Delivery Using Nanosized Layered Double Hydroxide, an Anionic Clay

A study was conducted to demonstrate drug delivery using nanosized layered double hydroxide (LDH), which was an anionic clay. Investigated revealed that layered double hydroxides represented one of the most promising materials in the areas such as nanomedicine, adsorbents, catalysis and catalyst supports , electrode modifier, and magnetic precursors, processing of selective chemical nanoreactors, and separation and membrane technology. Layered nickel hydroxide was used as an electrode for alkaline secondary cells in electrochemistry. The layered structure, wide chemical compositions, variable layer charge density, ion-exchange properties, reactive interlayer space, swelling in water, and rheological and colloidal properties made LDH look and behave like clay.

Bioceramics—A New Era

In the last few decades with the introduction of bioceramics, a special class of ceramics to perform tailored functional/biological/chemical activities in living systems, treatment procedure through reconstructive surgery has been revolutionized and this has resulted in marked improvement in quality of life of the rehabilitated persons. The procedure involves an innovative use of specially designed ceramics for reconstruction of diseased/damaged parts of body, e.g. hips, knees, wrists, spines, jaws, diseased long-bones and repair for maxillofacial, periodontal disease, etc. Bioceramics are produced in a variety of compositions, forms and phases and are often used in the form of bulk materials of specific shape to perform a special function, which are called implants, prostheses or prosthetic devices. They are also used in powder/granule forms to fill space of the damaged hard tissues, which through natural repair process get integrated and restore function, and as coatings to provide bio-friendly interface on substrate for cement-less fixation and sometimes also as a second phase in composites. In this review, different classes of bioceramics, their chemical compositions, structures, tailored functions and broad application areas have been outlined and the effects of their usage on treatment of different trauma/degenerative diseases have been discussed. Along with the current research status of the advanced laboratories around the world on this emerging subject, the developments made so far at CGCRI, Kolkata have also been outlined.

One pot synthesis of carbon dots decorated carboxymethyl cellulose-hydroxyapatite nanocomposite for drug delivery, tissue engineering and Fe3+ ion sensing

In this work, carbon dots conjugated carboxymethyl cellulose-hydroxyapatite nanocomposite has been synthesized by one-pot synthesis method and used for multiple applications like metal ion sensing, osteogenic activity, bio-imaging and drug carrier. The structure and morphology of the nanocomposite were systematically characterized by FTIR, XRD, TGA, FESEM, TEM and DLS. Results clearly demonstrated the formation of fluorescent enabled carbon dots conjugated nanocomposite from carboxymethyl cellulose-hydroxyapatite nanocomposite by a simple thermal treatment. The synthesized nanocomposite is smaller than 100 nm and exhibits fluorescence emission band around 440 nm upon excitation with 340 nm wavelength. In the meantime, the nanocomposite was loaded with a chemotherapeutic drug, doxorubicin to evaluate the drug loading potential of synthesized nanocomposite. Moreover, the as-synthesized nanocomposite showed good osteogenic properties for bone tissue engineering and also exhibited excellent selectivity and sensitivity towards Fe3+ ions.

Magnetic field–induced biomimetic synthesis of superparamagnetic poly (vinyl alcohol)–maghemite composite

Poly (vinyl alcohol)-mediated synthesis of monodisperse, self-assembled, superparamagnetic maghemite particles was carried out through a magnetic field-induced biomimetic route. Modifying the kinetics of precipitation, the magnetic C, field promoted the nucleation of the maghemite phase over magnetite and also induced a self-assembly-assisted shape anisotropy during the precipitation of the particles in the polymer matrix.