Nanoparticles Research Paper

LITERATURE PART

1. Nanoparticles (NPs)

Nanoparticles are particulate dispersion or solid particles with size ranging between 1and 100 nm. They are used as carriers of drug in the field of medicine for drug delivery due to their shape, size and chemical modification. These properties of nanoparticles have been found to influence cellular phagocytosis, determine targets, and are useful in peptide and polyethene glycol immobilization as well as loading and dissolution of drugs across biological barriers (Mitragotri 2009, Uchegbu et al. 2013).

Figure1: The various ways by which nanoparticles are used in the field of medicine. (Uchegbu et al. 2003)

1.1 Monolayer forming nanoparticles

Micelles are formed when amphiphilic compound, which

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1.3 Metal based nanoparticles

Metal based nanoparticles such as gold have been reported to be used in diagnostic and targeted drug delivery because of their ability to carry large drug doses and their possibility of surface modifications. For example, colloidal gold has been used in medicine for treating tuberculosis. Even though, it has been shown that cells are able to take up gold nanoparticles without cytotoxic effect, there are still concerns since significant accumulation of metal particles can be toxic (Naahidi et al. 2013, Diaz & Vivas-Meija 2013).

1.4 Porous Silicon (PSi) nanoparticles

Porous silicon nanoparticles, has received much attention due to its efficient in-vivo biocompatibility, chemical surface modification and easy control of the porous network structure especially for poorly water-soluble drugs (Mitragotri & Lahann 2009, Salonen et al. 2008). Oral bioavailability of drugs depends on the solubility and its ability to permeate the gastrointestinal tract (GIT) and the liver. Size of nanocarriers administered intravenous has shown to aid its opsonization by mononuclear phagocytic system (MPS) and its surface properties determines the amount and pattern to which blood protein binds (Moghimi et al.

This includes the modifications with amino terminal such as TOPSi-NH2 and TCPSI-NH2 (Wunjun et al. 2012).

TOPSi-NH2 UnTHCPSi-COOH

Figure 4: Modified and stabilized surfaces of Psi nanoparticles (Kovalainen et al. 2012)

1.6 Drug loading properties of PSi

Loading of drugs into PSi nanoparticles is carried out by capillary action and the drugs are retained either by physical trapping, covalent attachment or spontaneous adsorption. The chemical nature of the drug and the loading solution has also been reported to have effect on loading into porous silicon particles (Salonen et al. 2005, Uchegbu et al. 2013). Activation of functional groups at the end of PSi such as the carboxyl end groups on surface of particles with N-hydroxysuccinimide (HNS) in the presence carbodiimide has effect on the retainment of the drug (Sam et al.