Nanoparticles- A new approach

Nanoparticles are materials ranging from 1-1000 nm dimension. Size range of 1-500 nm is generally considered fine nano range while above 500 nm are considered coarse nanoparticles. (Adlin et al., 2009). Their unique physico-chemical characteristics like ultra-small size, large surface area to mass ratio and high reactivity differentiates them from materials having same composition and overcome some limitations found in traditional therapeutic and diagnostic agents (Aruna et al., 2013). Nanoparticles can be classified into two types: Nanospheres and Nanocapsules. In nanospheres, drugs are either adsorbed or entrapped inside the polymeric matrix. In nanocapsules, drugs are confined to the inner liquid core while the external surface of nanoparticles is covered by the polymeric membrane (Brigger et al., 2002).

                                      Fig: 1.1 Nanosphere (left), Nanocapsule (right)

 1.1  Based on structure of nanoparticles, these are classified as: (Gadad et al., 2014)

Fullerenes:  Bucky balls and carbon tubes belong to fullerene structural class, these are carbon based, lattice like, and potentially porous molecules.

Liquid Crystals: Liquid crystal types of pharmaceuticals are composed of organic liquid crystal materials that mimic naturally occurring biomolecules like proteins and lipids. They are considered as one of the safe methods for drug delivery and target specific areas of the body where tissues are inflammed, or where tumors are found.

Liposomes: Liposomes are lipid based liquid crystals, used extensively in the pharmaceutical and cosmetic industries because of their tendency to break down inside cells once their delivery function has met. Liposomes were the first engineered nanoparticles used for drug delivery but problems such as their propensity to fuse together in aqueous environments and release their payload led to replacement and use of newer alternative nanoparticles (Calvo et al., 1997).

 

 

 

 

                               Fig: 1.2 Liposomes

Nanoshells: They are also referred to as core shells, spherical cores of a particular compound surrounded by a shell or outer coating, which is a few nanometers thick (Nagavarma et al., 2012).

Quantum dots:  Quantum dots are nanosized semiconductors that, depending on their size, emit light in all colors of the rainbow. These materials confine conduction band electrons and valence band holes in all three spatial directions. Examples of quantum dots are Semiconductor nanocrystals and Coreshell nanocrystals, where there is an interface between different semiconductor materials. They have been applied in biotechnology for cell labelling and imaging, particularly in cancer imaging studies (Janes et al., 2001).

The kinetics of drug release from nanoparticles depend on the strength of hydrophobic interactions between the polymer and drug and polymer degradation rate. The uptake and distribution of nanoparticles is size dependent. Nanoparticles of size ~10 nm are utilized for extended circulation, while ~100 and ~200 nm particles are utilized for passive targeting and intracellular drug delivery respectively (Katas et al., 2013)


 Arranged by Div.