Receptor-mediated targeting of magnetic nanoparticles using insulin as a surface ligand to prevent endocytosis

Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging contrast agents or in drug delivery applications. Tissue and cell-specific drug targeting by these nanoparticles can be achieved by employing nanoparticle coatings or carrier-drug conjugates that contain a ligand recognized by a receptor on the target cell. In this study, superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared and coupled to insulin for their targeting to cell expressed surface receptors and thereby preventing the endocytosis. The influence of these nanoparticles on human fibroblasts is studied using various techniques to observe cell-nanoparticle interaction that includes light, scanning, and transmission electron microscopy studies. The derivatization of the nanoparticle surface with insulin-induced alterations in cell behavior that were distinct from the underivatized nanoparticles suggests that cell response can be directed via specifically engineered particle surfaces. The results from cell culture studies showed that the uncoated particles were internalized by the fibroblasts due to endocytosis, which resulted in disruption of the cell membrane. In contradiction, insulin-coated nanoparticles attached to the cell membrane, most likely to the cell-expressed surface receptors, and were not endocytosed. The presence of insulin on the surface of the nanoparticles caused an apparent increase in cell proliferation and viability. One major problem with uncoated nanoparticles has been the endocytosis of particles leading to irreversible entry. These results provide a route to prevent this problem. The derivatized nanoparticles show high affinity for cell membrane and opens up new opportunities for magnetic cell separation and recovery that may be of crucial interest for the development of cellular therapies

Aspects of Dielectric Breakdown in a Model for Disordered Nonlinear Composites

We study dielectric breakdown in a semi-classical bond percolation model for nonlinear composite materials introduced by us and the related breakdown exponent near the percolation threshold in two dimensions. The breakdown exponent after doing finite size scaling analysis is found to be $t_B \simeq$ 1.42. We discuss in detail the differences in our model from the traditional models for dielectric breakdown and argue that our result seems to be different from the standard result of 4/3 obtained in the previous models.Comment: 20 pages, LaTex file (6 postscript figures included

Suggestive role of eye-stalk of Macrobrachium gangeticum Bate, 1868 in regulation of its reproductive behaviour

Role of eye-stalk of Macrobrachium gangeticum Bate, 1868 in its reproductive behaviour has been examined by conducting deletion and addition experiments. Eye-stalk ablation induced gonadal maturity in both sexes, leading to change in colour and size of ovaries and increase in GSI and oocyte diameter in females and increased length of testes and diameters of seminiferous tubules in males. Injection of eye-stalk extracts tended to at least partly restrict the effects in both sexes. The experiments thus suggested that the eye-stalk of M. gangeticum released some gonad inhibiting factors

Histoarchitecture, seasonal variation and reproductive function of the neuroendocrine organ, brain of freshwater prawn, Macrobrachium gangeticum

Histoarchitecture, seasonal variation and reproductive function of the neuroendocrine structure, brain of freshwater prawn Macrobrachium gangeticum were studied. Three types of NSCs - 'B', 'C' and 'D' were found to be concentrated in four groups in brain. These cells showed larger diameters and higher activity during breeding season. In case of females, the 'C' cells were more active during vitellogenic period. Brain extracts were found to induce gonadal maturation of both males and females

Complex inversion and uniqueness theorems for a generalized Laplace transform

AbstractIn this paper a complex inversion formula for a generalized Laplace transform F(x)=Γ(A)Γ(B)∫0∞(xt)β1F1(A,B;–xt)f(t)dt where A=β+ν+1;B=α+β+ν:+1;β≥0and ν>0 has been obtained and extended to a class of generalized functions. A uniqueness theorem has been established for it

Characterization of Matrix Variate Normal Distributions

In this paper, it is shown that two random matrices have a joint matrix variate distribution if conditioning each one on the other the resulting distributions satisfy certain conditions. A general result involving more than two matrices is also proved

Effect of Non-uniform Temperature Gradient on Marangoni Convection in a Relatively Hotter or Cooler Layer of Liquid

The effect of non-uniform temperature gradient on the onset of convection driven by surface tension gradients in a relatively hotter or cooler layer of liquid is studied by means of linear stability analysis. the upper boundary is considered to be free and insulating where surface tension gradients arise on account of variation in temperature and the lower boundary is rigid. the single-term Galerkin technique is used to obtain the eigenvalue equation. Eigenvalues are obtained and presented for both thermally conducting and insulating cases of the lower boundary. this analysis predicts that in either case the critical eigenvalues for different non-uniform temperature gradients are greater in a relatively hotter layer of liquid than the cooler one under identical conditions otherwise. this qualitative effect is quite significant quantitatively as well

Characterization of Joint Density by Conditional Densities

In this paper the relationship between joint density and conditional densities is studied. An explicit formula is given for obtaining the joint density from the conditional ones. It is illustrated for the case of bivariate normal distribution

A Fixed Point Theorem In 2-Banach Space For Non-Expansive Mapping

Our object in this paper to discuss about fixed point theory in 2-Banach space also we established a fixed point theorem in 2- Banach space which generalized the result of many mathematician