# Recent Advances in Nanoparticle-Mediated Treatment of Inflammatory Bowel Diseases
## 5 Surface Modified Nanoparticles  
The surfactant employed in surface modification is responsible for the extent of nanoparticle accumulation in the inflamed colon in murine models of TNBS-induced colitis.  
Different surfactants were employed for the preparation of ethyl cellulose nanospheres in order to obtain different surface properties [21]. Charged (anionic and cationic) and uncharged (non-ionic) surfactants (Polysorbate 20-PS20, Sodium dodecyl sulfate-SDS, cetyltrimethylammonium bromide CTAB, poly(vinyl alcohol) (PVA)) were employed to prepare polymeric nanoparticles. Ethyl cellulose was used as a matrix for the preparation of polymeric nanoparticles by emulsion solvent evaporation method. The interactions between nanoparticles and RAW 264.7 macrophage and C2 BBe1 entoreycte cells, as well as the in vivo delivery of targeted drugs to inflamed colon tissue were tested using a TNBS murine model of colitis. Betamethasone encapsulated polymeric nanoparticles were prepared using different types of surfactant in order to test their therapeutic efficacy in the aforementioned animal model. The outcome demonstrated the significance of surface properties of nanoparticles in the therapeutic approaches of passive drug targeting in IBD, whose effect is of similar importance as that determined by the size of nanoparticles.  
Mucoadhesive chitosan surface (CS)-modified PLGA nanospheres were prepared as an oral peptide delivery system [22]. Surface-modified PLGA nanospheres were also explored as a possible non-viral carrier for gene delivery. The authors employed surface modification with chitosan as the technique proved that the uptake of such nanoparticlesby cultured cells is more rapid. NFkappaB decoy oligodeoxynucleotides (ODNs) are efficient in the treatment of IDB as a result of the suppression of proinflammatory cytokine expression. Their therapeutic efficiency in inflammation was observed in murine animal models both in vitro and in vivo.  
The nanospheres were evaluated for oral use with NF-kB decoy ODNs, observing their effects on inflammation in DSS-induced experimental colitis in rats. The authors also associated decoy ODN-loaded CS-PLGA NS in Caco-2 cell monolayers as an in vitro model of intestinal epithelium.  
Study outcomes indicated that NF-kB decoy ODN-loaded CS-PLGA NS given via the oral administration route were efficient in treating DSS-induced experimental colitis. Chitosan surface-modified PLGA nanospheres are ideal NF-kB decoy carriers as they are high-stability and low-cytotoxicity materials that facilitate interactions with the mucosa of the inflamed colon.  
The therapeutic efficacy of PLGA-tacrolimus (FK506) loaded polymeric nanoparticles was assessed following oral and rectal administration in two different murine models of colitis, TNBS-induced colitis and oxazolone colitis [23].  
Enhanced therapeutic efficiency was observed after rectal administration of FK506-NPs by a higher selectivity in adhesion to the inflamed tissue. Premature degradation or uptake of NPs could be avoided due to the rectal administration directly at the site of inflammation, in contrast to the oral route of administration.  
In conclusion, FK506-NP proved to be efficient colon targeted drug-delivery systems with minor impact on the surrounding healthy tissue and enhanced drug permeability at the site of inflammation compared with tacrolimus alone.