This study presents a targeted nanoparticle-aptamer bioconjugate for cancer chemotherapy, specifically targeting prostate-specific membrane antigen (PSMA) in prostate cancer. The bioconjugates consist of docetaxel (Dtxl)-encapsulated nanoparticles made from poly(lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) copolymer, surface-functionalized with A10 2'-fluoropyrimidine RNA aptamers that recognize PSMA. These bioconjugates show significantly enhanced in vitro cytotoxicity compared to non-targeted nanoparticles. In vivo, they demonstrate remarkable efficacy in reducing tumor size in LNCaP xenograft nude mice, with five out of seven mice achieving complete tumor regression and 100% survival over 109 days. In contrast, the non-targeted Dtxl-NP group had only 57% survival and two mice with complete tumor regression. The Dtxl-NP-Apt bioconjugates also showed reduced toxicity, with a mean body weight loss of 7.7% compared to 18% for Dtxl-NP. The bioconjugates were internalized by PSMA-expressing cells, leading to intracellular drug release and enhanced cytotoxicity. The study highlights the potential of nanoparticle-aptamer bioconjugates for targeted cancer therapy, with the advantage of using FDA-approved materials and non-immunogenic, stable aptamers. The results suggest that these bioconjugates could be a promising therapeutic option for localized prostate cancer.This study presents a targeted nanoparticle-aptamer bioconjugate for cancer chemotherapy, specifically targeting prostate-specific membrane antigen (PSMA) in prostate cancer. The bioconjugates consist of docetaxel (Dtxl)-encapsulated nanoparticles made from poly(lactic-co-glycolic acid)-block-poly(ethylene glycol) (PLGA-b-PEG) copolymer, surface-functionalized with A10 2'-fluoropyrimidine RNA aptamers that recognize PSMA. These bioconjugates show significantly enhanced in vitro cytotoxicity compared to non-targeted nanoparticles. In vivo, they demonstrate remarkable efficacy in reducing tumor size in LNCaP xenograft nude mice, with five out of seven mice achieving complete tumor regression and 100% survival over 109 days. In contrast, the non-targeted Dtxl-NP group had only 57% survival and two mice with complete tumor regression. The Dtxl-NP-Apt bioconjugates also showed reduced toxicity, with a mean body weight loss of 7.7% compared to 18% for Dtxl-NP. The bioconjugates were internalized by PSMA-expressing cells, leading to intracellular drug release and enhanced cytotoxicity. The study highlights the potential of nanoparticle-aptamer bioconjugates for targeted cancer therapy, with the advantage of using FDA-approved materials and non-immunogenic, stable aptamers. The results suggest that these bioconjugates could be a promising therapeutic option for localized prostate cancer.