Table 2. Effect of surface functionalization on QR uptake.

QR	Size (nm)	SolHy pH 7	SolHy pH 4
QR-E R1	15×3	−	+
QR-E R2	15×3	−	−
QR-F R1	35×4	−	+
QR-F R2	35×4	−	−

CdSe/CdS core/shell QRs were water transferred by means of an amphiphilic polymer and were stabilised by addition of high (R1) or low (R2) amount of diamino-PEG molecules to their surface via the EDC crosslinker chemisty (see Materials and Methods). Living Hydra were incubated in culture solution (SolHy) at pH 4 or pH 7 in presence of the indicated nanorod. QR-R1 conjugated with high amount of PEG, were uptaken by Hydra ectodermal cells at pH 4, while QR-R2 coated with less molecules were not.