A novel micelle platform consisting of amphiphilic DNA block copolymers is introduced for chemotherapeutic drug delivery, allowing combinatorial testing of the drug carrier system. Oligodeoxynucleotide modified targeting units are “clicked” into the micelle corona by hybridization, allowing perfect control of surface functionalities of the nanoparticle system. Cancer cells are efficiently killed when targeting units and chemotherapeutic act together within the DNA block copolymer aggregates.

The cellular uptake of DNA block copolymer micelles composed of DNA‐b‐PPO in Caco‐2 cells was studied. In particular it was investigated if the shape of micelle aggregates influences the internalization. Rod‐like polymeric particles were taken up 12 times more efficiently than their spherical counter parts although they were composed of the same constituents. Furthermore, it was observed that internalization of all the micelle systems was more efficient than the pristine DNA controls. A cytotoxicity assay proved the non‐toxic nature of DNA‐b‐PPO micelle aggregates.

Previous in vitro studies using Caco-2 cell monolayers suggested a possible interaction between green and black tea and folic acid at the level of intestinal absorption. The main purpose of the present study was to investigate a possible pharmacokinetic interaction between tea and folic acid in healthy volunteers. In an open-labeled randomized cross-over study, the pharmacokinetic interaction between tea and folic acid (0.4 mg and 5 mg) was investigated in healthy volunteers. Water was used as the reference drink. Subjects ingested 0.4 mg folic acid tablets with water, green or black tea (0.3 g extract/250 ml) or 5 mg folic acid tablets with water or green tea (0.3 g extract/250 ml). Blood samples were collected over a period of 8 h. Serum folate analysis was carried out by a competitive immunoassay which uses direct chemiluminescent technology. At the 0.4 mg folic acid dose, green and black tea reduced the mean C(max) of serum folate by 39.2% and 38.6%, and the mean AUC(0 --> infinity) by 26.6% and 17.9%, respectively. At the 5 mg folic acid dose, the mean C(max) of serum folate was reduced by 27.4% and the mean AUC(0 --> infinity) was decreased significantly by 39.9% by the co-application of green tea. The present results suggest an in vivo interaction between tea and folic acid with even low concentrations of green and black tea extracts yielding decreased bioavailabilities of folic acid.

In this present study it was aimed to determine whether the catechins contained in green tea and the whole extracts of Camellia sinensis (Theaceae) inhibit the uptake of folic acid by Caco-2 cell monolayers. Our results indicate that (-)-epigallocatechin 3-gallate (EGCG) and (-)-epicatechin 3-gallate (ECG) inhibit cellular folic acid uptake with IC50 values of 34.8 micromol/L and 30.8 micromol/L, respectively. Furthermore, green and black tea extracts were also found to inhibit folic acid uptake with IC50 values of approximately 7.5 and 3.6 mg/mL, respectively. According to these results, simultaneous intake of tea and folic acid may inhibit intestinal folic acid absorption. The consequences with respect to the folate status of the body will need to be examined in vivo.