Synthesis of Poly(ϵ-caprolactone) Microreactors from Freeze-Dried Microspheres

Poly(ϵ-caprolactone) microreactors were prepared by micro-volcanic rupture of freeze dried microspheres. Effects of three synthesis parameters viz polymer concentration, emulsifier concentration and stirring speed on size and morphology of microreactors were examined. Average diameter of microreactors showed substantial increase with increasing polymer concentration and reduced size with increasing polyvinyl alcohol (emulsifier) concentration and stirring speed, respectively. These miniaturised structures have potential applications in immunodiagnosis and drug delivery

Synthesis of mercaptopropionic acid stabilized CDS quantum dots for bioimaging in breast cancer

Semiconductor inorganic nanocrystals or quantum dots (QDs) are nowadays extensively used for imaging and analysis of biomolecules owing to their superior optical properties over conventional organic fluorophores. They have excellent potential for synthesizing molecular probes against various biological markers such as free antigens, cell surface markers/antigens, bacteria, viruses and tissues. Traditional synthesis protocols of the QDs generally lead to the formation of hydrophobic nanocrystals. For biological applications, post-synthesis modifications need to be introduced to render required hydrophilicity. However, such additional steps make the tiny QDs structures bulky, which is unwanted in subsequent in-vivo executions. The present work reports a simple method for the direct synthesis of hydrophilic carboxyl (–COOH) functionalized CdS QDs using mercaptopropionic acid as a sulfur source and stabilizer. This aqueous synthesis route avoids the requirement of extra surface modification steps. The size and surface morphology of the synthesized CdS QDs were studied by electron microscopy. The average diameter of the QDs has been found to be in the range of 2-3.5nm. Spectral studies confirmed the grafting of –COOH terminal on the synthesized nanocrystals. Band gap energy and the theoretical size of the particles were calculated and found in good agreement with the experimental analysis. Due to the size quantization effect, the estimated band gap energy (2.6eV) of the QDs was on a higher side than that reported (2.4eV) for the bulk material. The synthesized nanocrystals can be further conjugated with bio-molecules for high-throughput drug screening, clinical immunological assays and protein-protein interaction studies

Plasticizers Induced Formation of Microcapsules From Freeze Dried Polystyrene Microreactors

The article describes solvent induced preparation of polystyrene microcapsules from freeze-dried microreactors. An aqueous suspension of microreactors was exposed to a plasticizing solvent for a defined time period. Plasticizer molecules surround the polymer chains and repel the water molecules. It results in the movement of the monomers toward each other. The process leads to formation of microcapsules with a core-shell structure. For proof of concept, four plasticizing solvents, namely 1,4-dioxane, toluene, dichloromethane, and chloroform, were studied for annealing of the hollow particles. It was concluded that chloroform was the best plasticizer in terms of transforming microreactors into microcapsules

Synthesis and characterization of ZIF-8 nanoparticles for controlled release of 6-mercaptopurine drug

Zeolitic imidazolate framework (ZIF-8) has been synthesized at room temperature in aqueous medium. Their suitability as potential drug carrier for delivery of an anti-leukemia drug, 6-mercaptopurine (6-MP) is examined. 6-MP was loaded in situ into the ZIF-8 nanoparticles during synthesis. Both ZIF-8 and 6-MP@ZIF-8 have been characterized using various characterization tools. The structural integrity and phase purity of 6-MP@ZIF-8 nanoparticles was obtained through X-ray diffraction pattern and was comparable to that of sodalite type ZIF-8. FESEM micrographs of pure ZIF-8 showed hexagonal nanocrystals with well-developed facets and uniform particle size distribution of around 80–100 nm. Encapsulation of 6-MP into ZIF-8 resulted into a nearly two fold increase of size while preserving the well-developed facets and hexagonal morphology. The encapsulation of 6-MP was confirmed by UV-Visible and FTIR spectroscopy studies. Furthermore, the release kinetics of 6-MP drug from 6-MP@ZIF-8 has been investigated in phosphate buffer saline 37 °C at two different pH values 7.4 and 5.0. The 6-MP@ZIF-8 exhibited much faster release of drug in acidic pH as compared with release in pH 7.4 owing to the decomposition of ZIF-8 structure, thus, indicating the potential of ZIF-8 to be used as a carrier for controlled delivery of 6-MP against cancerous cells

Advanced Functional Structure-Based Sensing and Imaging Strategies for Cancer Detection: Possibilities, Opportunities, Challenges, and Prospects

Cancer is the second most common cause of death in the world. The principal limitations thus far encountered in the clinical practice of probing cancer are diverse and include low sensitivity, time consumption, bulkiness, and cost. In this respect, nanomaterial (NM)‐based sensing techniques are recognized as a superior alternative to efficiently resolve such limitations. A better understanding of NM‐based sensing platforms is thus important so that these novel avenues can easily be explored for clinical applications. These platforms have the merits of high sensitivity, high specificity, rapid response, and easy‐to‐read signals. This review offers a comprehensive survey of NM‐based advanced cancer‐sensing techniques and will help the scientific community establish optimum sensing strategies based on an accurate assessment of the interactions between cancer biomarkers and NM‐based platforms

Cyclodextrin-metal–organic framework (CD-MOF): From synthesis to applications

Porous coordination compounds, commonly known as metal–organic frameworks (MOFs), exhibit many unique characteristics (e.g., high surface area, high porosity, and tunability). The corresponding naturally occurring counterparts, CD-MOFs have opened a new avenue of research in light of its non-toxic, edible, and renewable nature. These characteristics have led to their applications into numerous directions including drug delivery, CO2 capture, separation/purification, adsorption, sensors, food packaging, electrical conductors, memristors, photocatalysis, and polymerization. In this review, we provide a brief discussion about the available technologies for the synthesis of CD-MOFs and their applications in many prospective areas

Removal of gaseous formaldehyde by portable photocatalytic air purifier equipped with bimetallic Pt@Cu-TiO2 filter

In this research, a mini-scale air purifier (AP) system was built with a series of honeycomb (HC) ceramic filters coated with 1 wt% Pt@Cu/TiO2 (AP (PCT-x), where x = 1, 2, and 3 for Pt:Cu weight ratios). The designed AP (PCT-x) photocatalytic systems were investigated for the removal of formaldehyde (FA) vapor under varying operational conditions (e.g., FA concentration (0.5-5 ppm), AP-flow rate (100-160 L/min), and UV light intensity (0.004-0.982 W)). The enhanced photocatalytic activities of AP (PCT-x) system (e.g., compared to the monometallic analogues) are suspected to reflect the synergistic role of Pt metal sites (in terms of high work function (5.93 eV) for the 111 crystal plane) in the Pt@Cu bimetallic structures and the high electronic transitions between Pt and Cu sites on the TiO2 surface. Nonetheless, their photocatalytic activities tend to decrease at higher Pt content (e.g., PCT-3 relative to PCT-2) due possibly to the formation of Pt clusters and associated shielding effect. Overall, AP (PCT-2) exhibited the highest efficacy (over five reuse cycles) to attain 100% removal of FA (0.5 ppm) within 5 min at an AP-flow rate of 160 L/min and UV light intensity of 0.982 W (quantum yield (QY) of 1.94E-04 molecules/photon and figure of merit (FOM) of 1.21E-06 L & BULL;mol/ (mg & BULL; J & BULL;h)). According to the in-situ DRIFTS analysis, Pt2@Cu metal sites were favorable to promote the transfer of photoinduced charge carriers by TiO2 so as to accelerate the oxidation reaction of FA vapor (e.g., through the generation of OH & BULL; and O2 & BULL;- radicals). This study offers practical insights into the potential of controlled tuning of redox dynamics (i.e., between Pt and Cu metal sites on TiO2) in the enhancement of the photocatalytic performance for air purification system

Transportation of Drug-(Polystyrene Bead) Conjugate by Actomyosin Motor System

The Nanorobotics and cargo transportation application of molecular motors is of recent intent. The present study explores the transportation of Mesalamine/5-aminosalicylic acid/5-ASA drug by molecular motors. Mesalamine is an anti-inflammatory drug used to treat Crohn's disease and ulcerative colitis. Conjugate of mesalamine and polystyrene (Dia.: 3 μm) beads was prepared by amide linkage between amine (-NH2 group of drug and carboxyl (-COOH) group of the bead. In Fourier Transform Infrared spectra, peaks were observed at 3428.1 and 1654.0 cm-1 for N-H and C=O stretching bond respectively confirming the amide bond formation between drug and microbeads. Quantification of 5-ASA attached to polystyrene bead was done by UV-vis spectroscopy and it was ascertained that 93% of 5-ASA was loaded on polystyrene beads. Conjugate of drug-polystyrene beads were then covalently attached to actin filaments. Velocity of actin filaments attached to drug loaded beads in in-vitro motility assay reduced to 0.89 m/s as compared to free actin velocity (4.64 m/s). This further ascertains the microcomposites formation. The present study provides an insight into the actin-myosin based molecular motor systems for an efficient tool for drug transportation

Development and Evaluation of Novel Biodegradable Docetaxel Loaded Microspheres of Poly (D, L-Lactide-Co-Glycolic acid) and Poly (ε-Caprolactone)for Controlled Drug Delivery.

The main objective of this study was to develop a polymeric drug delivery system for controlled release of docetaxel. This system was capable of improving the therapeutic index of drug and devoid of adverse effect of polysorbate 80 in Taxotere. Polycapro-ε lactone (PCL) and poly (lactic –coglycolic acid) (PLGA) microspheres were prepared by solvent evaporation method. Solvent evaporation method was used for the successful entrapment of drug with in polymer particles. The influence of different processing parameters on the size and surface morphology of microspheres was evaluated. Effect of docetaxel concentration on encapsulation efficiency and released pattern was also studied. We achieved good encapsulation efficiency i.e 92.19 ± 0.23, 86.38 ± 0.02 for F1 ( 1:2 Drug: PCL) and F4 ( 1:2 drug : PLGA) formulations respectively. Cumulative % drug released was found 56.95± 0.024 for PCL (F1) and 80.54± 0.035 for PLGA (F4) formulation after 30 days incubation in PBS buffer (pH 7.4). Both the formulation followed higuchi model and the release mechanism was found non fickian on the basis of diffusion exponent value of 0.86 and 0.83 for F1 and F4 formulation respectively. The formulations were found stable and very effective for controlled drug delivery