## 1 Introduction  
Triple negative breast cancers (TNBC) are high-risk and highly aggressive metastatic types of malignancies [1, 2]. TNBC is so called due to the absence of expression of estrogen receptors (ER), progesterone-receptors (PR) and human epidermal growth factor receptor 2 (HER2) [1]. TNBC not responsive to established hormone therapies and anti-HER2 therapy that are designed to target ER, PR or HER2 receptors [1]. Therefore, in addition to surgical resection, TNBC is usually treated with radiotherapy or chemotherapy, or a combination of both, which are non-targeted treatments associated with short- and long-term side effects [3, 4, 5]. Due to the lack of tumor-specific predictive biomarkers [2], TNBC has overall poorer prognosis and clinical outcomes compared to other breast cancer subtypes, and is also associated with limited treatment options [6]. Among the subtypes of breast cancers, TNBC accounts for approximately 15% of all breast cancers but is associated with disproportionate high rates of recurrence and mortality [3; 7]. Patients diagnosed with metastatic TNBC were shown to have a median survival of approximately 13 months [8]. Furthermore, the limitations and misinterpretations in current breast cancer screening techniques also lead to the delay of prognosis of TNBC. For example, TNBC is likely to exhibit benign morphological features in ultrasound (US) imaging and mammography [9]. On the other hand, magnetic resonance imaging (MRI) is shown with the ability to detect suspicious features of the TNBC tumors which are interpreted as benign masses by conventional radiological imaging [9; 10]. Therefore, improved screening and imaging methodologies are clearly needed in the diagnostic screening and disease monitoring in TNBC to facilitate treatment efficacy [11]. As one of the widely used imaging modalities in breast cancer management, MRI is a non-invasive medical imaging technique that does not use ionizing radiation [12; 13]. MRI signal is related to the differences in the magnetic moments of the protons (in water molecules) in their excited and relaxed states in the area of interest [14]. As the human body is largely composed of water, when within in a magnetic field, the protons have their magnetic moments aligned initially to the direction of the applied external magnetic field [15]. When an RF electromagnetic field is applied, their magnetic moments change [15]. Upon the removal of the RF signal, the magnetic moments of the protons gradually return to their original states [16]. The recovery process is characterized by two relaxation mechanisms, the spin-lattice relaxation process T1 (longitudinal relaxation) and the spin-spin T2 (transverse relaxation). Since the relaxation times (T1 and T2) of the protons in different tissues differ, the structures of \"normal\" and \"diseased\" tissues can, therefore, be distinguished [14; 17]. To further improve MRI sensitivity and analysis of specific anatomical sites, magnetite nanoparticles have been developed and used as contrast agents to generate anatomical and functional MR images for pathophysiological information [14]. These materials are exceptional candidates as contrast agents in MRI due to the combined advantages of their magnetic properties, biocompatibility, and applicability to in vivo studies [14; 17; 18]. When magnetite nanoparticles are introduced into the body, they generate an additional magnetic field (under externally applied magnetic field, i.e., by MRI) that affects those of the nearby hydrogen protons [14]. The combined magnetic moments lead to a reduced relaxation time of protons in the vicinity [17]. Magnetic nanoparticles mainly shorten the T2 relaxation times of the tissues in which they accumulate and generate negative contrast (darkening) on T2 weighted images that are often used for the enhanced visualization and the detection of diseased tissues [14].