The physicochemical properties of the nanoparticle surface determine the performance of nanocomposites in biomedical applications such as their biodistribution and pharmacokinetics. The physicochemical properties of chitosan, such as apparent charge density and solubility, are pH dependent. Similarly, Fe₃O₄ nanoparticles are susceptible to variations in their physicochemical properties due to changes in pH. In this work, we evaluated the physicochemical properties of chitosan–magnetite nanocomposites that were suspended at pH 7.0, 9.0, and 11.0 to determinate the effect on particle size, zeta potential, and mass percentage of the polymeric coating, in addition to the crystalline phase and magnetic properties of magnetite phase. X-ray diffraction results exposed that the present phase was magnetite with no other phases present and that the crystallite size was between 10.8 and 14.1 nm. Fourier transform infrared verified the chitosan functional groups in treated samples while the percentage of mass determined by TGA found to be nearly 9%. Scanning electron microscopy micrographs corroborated the spherical shape of the bare and chitosan-coated nanoparticles. Dynamic light scattering results showed that chitosan coating modifies the zeta potential, going from a potential of −11.8 mV for bare particles to −3.0 mV (pH 11). Besides, vibrating sample magnetometer measurements showed that coercivity remained very low, which is desirable in biomedical applications.

纳米颗粒表面的物理化学性质决定了纳米复合材料在生物医学应用中的性能，例如它们的生物分布和药代动力学。壳聚糖的物理化学特性，例如表观电荷密度和溶解度，取决于 pH 值。同样，Fe ₃ O ₄由于 pH 值的变化，纳米颗粒很容易受到其物理化学性质的变化的影响。在这项工作中，我们评估了悬浮在 pH 值 7.0、9.0 和 11.0 下的壳聚糖-磁铁矿纳米复合材料的物理化学性质，以确定除结晶相外对聚合物涂层的粒径、zeta 电位和质量百分比的影响和磁铁矿相的磁性。X 射线衍射结果表明，本相是磁铁矿，不存在其他相，晶粒尺寸在 10.8 和 14.1 nm 之间。傅里叶变换红外验证了处理样品中的壳聚糖官能团，而由 TGA 确定的质量百分比发现接近 9%。扫描电子显微镜显微照片证实了裸露和壳聚糖涂层纳米颗粒的球形。动态光散射结果表明壳聚糖涂层改变了 zeta 电位，从裸粒子的 -11.8 mV 电位到 -3.0 mV (pH 11)。此外，振动样品磁力计测量表明矫顽力仍然非常低，这在生物医学应用中是可取的。