Early lab tests suggest the nanocarrier stays stable in water, responds to pH changes and shows anticancer activity in breast cancer cells.
Study: g-Fe2O3 Modified with Melamine-based Dendrimer as a New Dispersible and Hydrophilic pH-responsive Nanomagnetic Carrier for Doxorubicin Delivery. Image Credit: Andrey_Popov/Shutterstock.com
A study in Nanochemistry Research describes a nanomagnetic drug-delivery platform, IO@MBD, built from γ-Fe2O3 (IO) nanoparticles coated with a melamine-based dendrimer. The nanocarrier is hydrophilic, dispersible, and pH-responsive, and was designed to carry the anticancer drug doxorubicin (DOX).
The authors show that the platform supports controlled, acidity-triggered drug release and produces encouraging in vitro activity against breast cancer cells.
A wide set of physicochemical tests confirmed the material’s structure, colloidal stability, and magnetic behavior.
Together, the findings position IO@MBD as a promising platform for pH-responsive doxorubicin delivery, although magnetic targeting itself was not directly demonstrated in this study.
Saving this article? Download a PDF here.
The Importance of this Nanocarrier in Breast Cancer Chemotherapy
Doxorubicin remains one of the most widely used chemotherapy drugs for breast cancer and other solid tumours.
Its benefits are well established, but so are its drawbacks, including systemic toxicity, cardiotoxicity, and the potential for drug resistance. That has made targeted and stimuli-responsive delivery systems a major area of interest in cancer nanomedicine.
Magnetic nanoparticles are appealing in this context because they are biocompatible, easy to modify, and can respond to external magnetic fields.
On their own, however, they tend to aggregate and do not provide enough surface functionality for stable drug attachment. Surface engineering is therefore essential if they are to work as reliable carriers.
That is where dendrimers come in. Their highly branched structure, water solubility, and large number of reactive surface groups make them useful for drug loading and transport.
In this study, the researchers focused on a lower-generation melamine-based dendrimer, aiming to retain performance while avoiding the greater cost and synthetic complexity often associated with higher-generation systems.
Building the Anticancer Nanocarrier
The nanocarrier was prepared through stepwise surface modification of γ-Fe2O3 nanoparticles.
The particles were first chlorinated and then reacted with melamine to form IO@M (G0.5). A subsequent reaction with epichlorohydrin produced IO-M-ECH (G1), followed by a second melamine functionalisation step to generate the final melamine-based dendrimer shell, IO@MBD (G1.5).
Doxorubicin was then attached to the dendrimer-coated particles through a Schiff-base linkage formed between aldehyde groups on DOX and amine groups on the dendrimer surface. Ultraviolet–visible spectroscopy indicated a drug loading of about 17 wt%.
Material Tests
The team used Fourier-transform infrared spectroscopy and X-ray diffraction to confirm surface functionalisation and retention of the crystalline maghemite structure. Transmission electron microscopy and field-emission scanning electron microscopy were used to assess particle morphology and size.
Dynamic light scattering and zeta potential measurements were used to evaluate colloidal behaviour, while thermogravimetric analysis and CHN elemental analysis helped verify dendrimer grafting.
Drug release was studied in phosphate-buffered saline at pH 7.4, 6.5, and 5.5 at 37 °C. The paper’s methods section describes measurements out to 96 hours, although the reported release results extend to 54 hours.
The researchers also carried out MTT cytotoxicity assays in MCF-7 breast cancer cells after 24 and 48 hours, comparing free DOX, DOX-loaded IO@MBD, and unloaded IO@MBD.
Results of the Study and Potential
The analytical data support the successful formation of the dendrimer-coated carrier. FT-IR spectra showed the expected triazine and amine bands, while CHN analysis recorded an increase in nitrogen content from 9.88 % in IO@M to 17.50 % in IO@MBD, consistent with greater dendrimer loading.
Thermogravimetric analysis showed about 11.6 % weight loss attributed to dendrimer decomposition.
The colloidal data were also notable. IO@MBD had a hydrodynamic size of 106.6 nm, smaller than bare IO at 254.4 nm and IO@M at 265.3 nm.
Its zeta potential shifted to -44.8 mV, indicating improved colloidal stability through stronger electrostatic repulsion. Transmission electron microscopy showed well-dispersed spherical particles with an average core size of around 15 nm, while FESEM and EDS mapping confirmed the expected elemental distribution of Fe, C, N, and O.
Magnetic measurements showed that IO@MBD retained strong magnetic character after surface modification. The saturation magnetisation fell slightly from 76.43 emu g-1 for bare IO to 70.71 emu g-1 for IO@MBD, which is consistent with the addition of a non-magnetic organic shell.
The lack of hysteresis indicated superparamagnetic behaviour, suggesting the material remains suitable for future magnetic-targeting applications, even though such targeting was not tested directly here.
pH-Responsive Drug Release
One of the study’s central findings is the carrier’s pH-responsive release profile. The Schiff-base linkage between DOX and the dendrimer shell is acid-labile, allowing the drug to be released more readily under acidic conditions similar to those found in tumour-related environments.
The release profile showed no early burst effect and followed an exponential trend during the first 24 hours. After 54 hours, about 80 % of the drug had been released at pH 5.5, compared with roughly 45 % at pH 7.4.
That pattern supports the authors’ claim that the system can hold the drug more effectively under near-physiological conditions while releasing it more efficiently in acidic environments.
Cancer Cell Results
In MCF-7 breast cancer cells, the DOX-loaded nanocarrier showed cytotoxic activity comparable to free doxorubicin overall, with stronger anticancer effects appearing at 48 hours.
The reported IC50 values were 20 µg/mL for free DOX at both 24 and 48 hours, compared with 30 µg/mL at 24 hours and 10 µg/mL at 48 hours for IO@MBD@DOX.
The unloaded carrier, IO@MBD, also showed mild cytotoxicity. That is an important point, because it means the material itself was not completely inert under the test conditions.
Even so, the broader result suggests that the carrier can deliver DOX effectively while offering the added advantages of hydrophilicity, dispersibility, and pH-responsive release.
The Lower-Generation Design Stands Out
A key argument in the paper is that this system achieves useful performance without relying on a more elaborate, higher-generation dendrimer.
According to the authors, this could reduce both synthesis cost and laboratory complexity while preserving the features needed for controlled drug delivery.
That makes the work interesting not only as a proof-of-concept for doxorubicin delivery, but also as an example of how simpler dendrimer architectures can still provide meaningful functionality when combined with magnetic nanoparticles.
Conclusion and Next Steps
This is a materials-focused, in vitro study rather than a demonstration of therapeutic targeting in animals or patients. However, it provides a clear and carefully characterised example of a lower-generation dendrimer-magnetic hybrid nanocarrier that can load doxorubicin, remain dispersible in water, respond to pH, and retain superparamagnetic behaviour.
Future work will need to test biodistribution, in vivo safety, and whether external magnetic fields can improve localisation in real biological systems.
Journal Reference
Zarei, H., et al. (2026). γ -Fe2O3 Modified with Melamine-based Dendrimer as a New Dispersible and Hydrophilic pH-responsive Nanomagnetic Carrier for Doxorubicin Delivery. Nanochemistry Research, 11(1), 112–124. DOI:10.22036/ncr.2025.515140.1465
