In this paper, the influence of the various degradation conditions, on the molecular and supramolecular structure of polybutylene succinate (PBS) and polybutylene succinate adipate (PBSA) copolymer during degradation is described. The experiment was carried out by the use of injection molded samples and normalized conditions of biodegradation in soil, composting and artificial weathering. Materials were studied by size-exclusion chromatography (SEC) coupled with multiangle laser light scattering (MALLS) detection and wide-angle X-ray diffraction (WAXD). Additionally, the physical and mechanical properties of the samples were determined. The performed experiments clearly show difference impacts of the selected degradation conditions on the macroscopic, supramolecular and molecular parameters of the studied aliphatic polyesters. The structural changes in PBS and PBSA explain the observed changes in the physical and mechanical properties of the obtained injection molded samples.

Microbial infections lead to elevated inflammatory responses, which usually result in prolonged and incomplete wound healing. Therefore, there is an increasing demand for biodegradable fibres that are effective against a different range of microorganisms, especially those with antibiotic resistance. Herein, quercetin-(Q)-loaded polylactide-based fibres were developed using the electrospinning technique. Since Q exhibits low chemical stability, we used star-shaped polylactides (PLAs) with a β-CD core to host Q by inclusion complexation. To enhance the stability of the fibres and additionally entrap the Q between polymeric chains, we adapted supramolecular cross-linking by the stereocomplexation of PLAs with opposite configurations. As a control, we prepared an additional formulation of star-shaped/commercial PLA/Q for the preparation of nonwovens in which the β-CD moiety was not present. All developed fibres were smooth and continuous, with an average diameter of 37 μm. Although nonwovens did not possess diffusible activity, good antibacterial effects against Staphylococcus aureus (S. aureus), Escherichia coli (E.coli) and Klebsiella pneumoniae (K. pneumoniae) were observed. All these features validate the proposed approach, in which different supramolecular interactions were used to modify the properties of PLA-based fibres and, most importantly, show their great potential usefulness against microbial infections.

Cyclodextrins (CD) are a group of cyclic oligosaccharides with a cavity/specific structure that enables to form inclusion complexes (IC) with a variety of molecules through non-covalent host-guest interactions. By an elegant combination of CD with biocompatible, synthetic and natural polymers, different types of universal drug delivery systems with dynamic/reversible properties have been generated. This review presents the design of nano- and micro-carriers, hydrogels, and fibres based on the polymer/CD supramolecular systems highlighting their possible biomedical applications. Application of the most prominent hydrophobic aliphatic polyesters that exhibit biodegradability, represented by polylactide and polycaprolactone, is described first. Subsequently, particular attention is focused on materials obtained from hydrophilic polyethylene oxide. Moreover, examples are also presented for grafting of CD on polysaccharides. In summary, we show the application of host-guest interactions in multi-component functional biomaterials for controlled drug delivery.