A pH-responsive nanocarrier of peanut shell carbon quantum dots as a promising delivery of doxorubicin for cancer therapy.

Carbon quantum dots (CQDs) have shown great potential for drug delivery systems due to their small size and properties. Surface functionalization of CQDs directly affects the drug conjugation and release behaviour. In this study, the peanut shell carbon quantum dots (PS-CQDs) were synthesised through the hydrothermal method. The as-synthesised PS-CQDs had blue fluorescence and functional groups of hydroxyl, carboxyl, and amine. These surface group shows that the PS-CQDs have great water solubility. The free radical scavenging efficacy was also analysed and found to be 84.7%. With an average size of 2.1 ± 0.02 nm, the PS-CQDs were functionalized with a hydrazine group and then conjugated with doxorubicin. The doxorubicin conjugated sample DOX-PS-CQDs showed pH-sensitive release of the drug. The cumulative release percentage was 55.4% at pH 7.4 and 81.4% at pH 6.5, and the release profile exhibited sustained release within 24 h. The different pH enables the PS-CQDs based nanocarrier to release the drug at tumour sites efficiently. Further, in-vitro anticancer activity was studied using these PS-CQDs based nanocarriers against the MDA MB231 cell line, and the live/dead cell screening was carried out by AO/EB staining. Thus, the doxorubicin conjugated with PS-CQDs has exhibited promising properties as a drug carrier for cancer therapy.