In situ nanomechanical characterization of the early stages of swelling and degradation of a biodegradable polymer

The interactions of a biodegradable scaffold with cells or living tissues depend on the time-evolution of the nanoscale properties of the scaffold. We present an in situ quantitative study on the early-stage swelling and degradation of poly(lactic-co-glycolic acid) (PLGA). A novel metrology scheme based on force microscopy measurements of the patterns of PLGA nanostructures is developed to characterize the evolution of topography, volume and nanomechanical properties. The volume and nanoscale roughness show an oscillating behaviour during the first eight days of immersion; at a later stage, we observe a continuous decrease of the volume. The effective Young's modulus exhibits a monotonic decrease from an initial value of about 2.4 GPa down to 9 MPa at day 14. The oscillating behaviour of the volume before the onset of full degradation is explained by a coupled diffusion-swelling mechanism. The appearance of a second maximum in the volume evolution results from the competition between swelling and degradation.

The non-innocent nature of graphene oxide as a theranostic platform for biomedical applications and its reactivity towards metal-based anticancer drugs

The self-assembly process of a mononuclear iron(ii) complex as anticancer agent with graphene oxide (GO) unveils the ability of GO to oxidize the metal drug.

The power laws of nanoscale forces under ambient conditions

We report a power law derived from experimental atomic force microscopy (AFM) data suggesting a nano to mesoscale transition in force–distance dependencies.