Doxorubicin delivery of green-synthesized gold nanoparticles to MDA-MB-231 cells and collagen type II identification from yellow nose skate cartilage

Upcycling and green synthesis strategies have been applied for the synthesis of gold nanoparticles (AuNPs) using yellow nose skate (Dipturus chilensis) cartilage extract as a reducing and stabilizing agent (skAu). Doxorubin (DOX) was loaded onto the skAu, and the average size of the DOX-loaded AuNPs (c-skAuD) was measured to be 14.6 ± 0.5 nm by high-resolution transmission electron microscopy. Reaction parameters such as reaction time and DOX concentration were optimized for preparing c-skAuD. DOX was successfully loaded, as confirmed by the FT-IR results. In addition, FT-IR characterization revealed that chondroitin sulfate and collagen in the extract were involved in the synthesis of skAu. Although c-skAuD is cytotoxic to four different types of cancer cells (AGS, HeLa, A549 and MDA-MB-231), their cytotoxic effects were greatest on MDA-MB-231 cells. Analyzing cytotoxicity onto MDA-MB-231 cells revealed that c-skAuD had the greatest cytotoxicity, followed by a positive control (c-citAuD) and DOX. Furthermore, this cytotoxicity was dependent on the incubation time and DOX concentration. Cellular uptake of Au by inductively coupled plasma‒mass spectrometry demonstrated that compared with AGS cells (15.1%), MDA-MB-231 cells showed approximately two-fold greater Au uptake (29.9%) of c-skAuD. However, the Au uptake of the positive control (c-citAuD) did not significantly differ between the MDA-MB-231 and AGS cells. Moreover, collagen type II was identified in the extract by peptide analysis using LC‒ESI‒MS/MS. To the best of our knowledge, we are the first to report collagen type II in D. chilensis cartilage.