A novel sensing system based on fluorescence resonance energy transfer (FRET) between CdTe quantum dots (QDs) and Rhoda-mine B (RB) was established for the detection of matrix metalloproteinases (MMOL/LPs). In this system, 535-nm-emitting quantum dots (QDs) were bound to Rhodamine B (RB) via a MMOL/LP-specific peptide. A 76% reduction in luminescence was achieved because of FRET. Release of RBs by peptide cleavage restores radiative QD photoluminescence. Initial studies observed a 73% rise in luminescence over 60 min. The design platform of the nanosensor is flexible and can be fine-tuned for a wide array of applications such as the detection of biomarkers, early diagnosis of disease, and monitoring therapeutic efficacy simply by changing the sequence of the peptide linker.
In this study, an amphiphilic copolymer folate-succinyl-methionine-chitosan-octyl (FSMCO) was successfully synthesized step by step for self-assembling polymeric micelles. The copolymers formed micelle-like nanoparticles by their amphiphilic characteristics and structures were examined by UV-Vis absorption and Fourier transform spectroscopy. The sizes of blank and ICG derivativeloaded micelles measured by dynamic light scattering were about 170 and 140 nm, respectively, which were spherical in shape with an average zeta potential of 10 mV. Further studies on the stability showed that the micellar solutions maintain their sizes at room temperature for 1 month without distinct aggregation or dissociation. ICG derivative was much better photostable after being entrapped by the new carrier. The prepared FSMCO micelles displayed a good drug loading content (11.7%), entrapment efficiency (66.5%) and sustained release rate for the model drug fluorescein. The copolymers demonstrated weeny cytotoxicity toward Bel-7402, L02 and A549 cells when incubated for 2 d. Ligands modified micelles endowed preferable cell targeting capability and beautiful cell inhibition of HCPT-FSMCO on Bel-7402 tumor cells. This kind of polymeric micelles may be a promising nanovehicle in delivering near-infrared dyes for tumors imaging and chemotherapeutic drugs for cancer therapeutics.
