Stimuli-responsive drug-delivery nanocarriers (DDNs) have been increasingly reported
in the literature as an alternative for breast cancer therapy. Stimuli-responsive DDNs
are developed with materials that present a drastic change in response to intrinsic/chemical
stimuli (pH, redox and enzyme) and extrinsic/physical stimuli (ultrasound, Near-infrared
(NIR) light, magnetic field and electric current). In addition, they can be developed using different
strategies, such as functionalization with signaling molecules, leading to several advantages,
such as (a) improved pharmaceutical properties of liposoluble drugs, (b) selectivity
with the tumor tissue decreasing systemic toxic effects, (c) controlled release upon different
stimuli, which are all fundamental to improving the therapeutic effectiveness of breast cancer
treatment. Therefore, this review summarizes the use of stimuli-responsive DDNs in the treatment
of breast cancer. We have divided the discussions into intrinsic and extrinsic stimuli and
have separately detailed them regarding their definitions and applications. Finally, we aim to
address the ability of these stimuli-responsive DDNs to control the drug release in vitro and
the influence on breast cancer therapy, evaluated in vivo in breast cancer models.
