Silica nanoparticles: synthesis and functionalization for drug delivery application

Mesoporous silica nanomaterials are typically synthesised from surfactant molecules, acting as a templates or structure driving agents. The pore diameters, orderedness of pores, pore wall thickness etc. can be easily controlled by choosing a particular type of surfactant molecule and by varying the reaction conditions. Such chemical control provides the pathway to generate engineered mesoporous silica materials that can have a very high surface area up to 1000 m2/g and the pore diameter can also be varied from 2-10 nm. At present, we are studying the controlled release profile of these materials. Also, the effect of introduction of organic functionality on the particle morphology is under investigation. These mesoporous nanoparticles with dimensions below 100 nm can be exploited for in vivo drug delivery application. Currently, we intend to develop a silica nanoparticles drug delivery system, which is designed to work for colon cancer model. For this, the silica nanoparticles were first loaded with anticancer drug and then capped with bio-degradable polymer, which can be easily degraded by glycosidases specifically localised in the colonic region, rendering ‘specificity’ property to the drug carrying capped silica nanoparticles. We believe that the knowledge obtained from this study would help to design mesoporous materials for efficient controlled release agent

Quantum random walk : effect of quenching

We study the effect of quenching on a discrete quantum random walk by removing a detector placed at a position $x_D$ abruptly at time $t_R$ from its path. The results show that this may lead to an enhancement of the occurrence probability at $x_D$ provided the time of removal $t_R < t_{R}^{lim}$ where $t_{R}^{lim}$ scales as $x_D{^2}$. The ratio of the occurrence probabilities for a quenched walker ($t_R \neq 0$) and free walker ($t_R =0$) shows that it scales as $1/t_R$ at large values of $t_R$ independent of $x_D$. On the other hand if $t_R$ is fixed this ratio varies as $x_{D}^{2}$ for small $x_D$. The results are compared to the classical case. We also calculate the correlations as functions of both time and position.Comment: 5 pages, 6 figures, accepted version in PR