We report here, what we believe to be the first time, the successful transport of bioconjugated quantum rods (QRs) across an in vitro blood-brain barrier (BBB) model via a receptor-mediated transport, as well as the use of QR multiplexing technique to compare simultaneously the transmigration efficiency of different biomolecules across the BBB. The migration rate of bioconjugated QRs crossing the in vitro BBB was found to be concentration- and time-dependent. This work illustrates a nanoparticle-based platform that will not only allow a direct visualization of the transmigration ability of various kinds of biomolecules across the BBB, but also facilitate the development of novel diagnostic and therapeutic nanoprobes for early diagnosis and therapy of various disorders of the brain following systemic administration.