The topology and subtle compositional and sequence heterogeneity of macromolecules play a profound role in encoding information, selectivity, and function—yet these aspects remain underexplored. Here, I present two classes of macromolecules whose structural design unlocks emergent behaviors.
First, I introduce hydrophilic arborescent polymers: high-molecular-weight dendritic macromolecules with a regular, multilevel branched topology and a dense periphery of over 500 functional end-groups. Devoid of cross-links or loops, their colloid-to-molecule duality is striking at interfaces, where they spread into one-monomer-thick discs. This adaptable flexibility, coupled with multivalency stemming from the myriad of end-groups, offers potential for designing advanced therapeutics capable of enveloping and inactivating targets.
Next, I present ionically linked comb polymers (iCPs), synthesized by appending anionic surfactants with lipid-long alkyl tails to cationic residues sparsely distributed on an acrylic hydrophilic backbone. In water, iCPs self-assemble into vesicles —combisomes— featuring membranes consisting of a bilayer of the hydrophobic tails flanked by the hydrophilic backbones tightly adsorbed. This architecture decouples membrane thickness, flexibility and lateral mobility from polymer chain length. Enabling mimicking natural membranes beyond other macromolecular amphiphiles such as block copolymers. Remarkably, combisomes exhibit bactericidal activity through a phagocytosis-like mechanism. Their superpredatory behavior stems from the stochastic topology of iCPs, where some have packing parameters incommensurate with forming bilayers. When forced into one, they act as molecular springs that propel bacterial engulfment, membrane fusion, and effective killing of the pathogen.
These discoveries showcase the power of topological engineering in macromolecular design, opening new avenues for functional materials and bioinspired applications.

Zwitterionic polymers have gained great attention as versatile hydrophilic components for a wide range of materials, with applications ranging from biomedical science to nanotechnology. So far, zwitterionic polymers were classified as either polybetaines or polyampholytes. In recent years, an increased understanding of the structure-property relationship has revealed the importance of the linker length separating the positive and negative charges as well as the nature of the ions and backbone.
My group rationally designed polymeric ylides as a new form of overall-charge neutral polymers with zwitterionic character and demonstrated that polymeric sulfur and phosphorus ylides successfully prevent biofilm formation by pathogenic bacteria. 1,2 Structurally, polymeric ylides differ significantly from polyampholytes and polybetaines by having the negative directly adjacent to the positive charge, minimizing the dipole and providing sterically non-demanding residues. We show that the distinct hydrogen-bond acceptor capabilities of poly(sulfur ylides) and its selective toxicity towards bacterial cells make it an appealing addition to the available toolkit of antifouling polymers. While polymeric sulfur ylides display toxicity towards bacteria, they do not affect eukaryotic cells, making them attractive materials for medical coatings. In addition, we gained an in-depth understanding of structure-property relationships by accessing diverse polymer structures with varying backbone and ylide scaffolds.3,4 I will conclude the talk by presenting examples showcasing how my group employs poly(ylides) to design new generations of nano-carriers, offering distinct advantages over existing polyethylene glycol-based systems, and highlighting their potential to open new directions and opportunities in the field of nanomedicine.5

We developed and evaluated physicochemical properties of polymer brushes based on poly(4-vinylpyridine) (P4VP) modified with Cu nanoparticles (CuNPs). These coatings were fabricated to serve as biocompatible and antibiocidal cell sheet engineering platforms enabling detachment of cell sheets by temperature-dependent modulation of their properties.

To characterize the chemical composition and surface morphology of the coatings, we employed atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Thermoresponsive properties of the coatings were evaluated by water contact angles measurements and UV-Vis absorbance spectra collection across a range of temperatures.

Microbiological testing demonstrated significant antibacterial properties of CuNP-modified P4VP brushes. Contact- and release- based killing mechanisms were investigated. The release of CuNPs from the P4VP brushes in water was additionally quantified using XPS.

Biocompatibility of the brushes was suggested by successful culturing of retinal pigment epithelium cells on the coatings, alongside a viability assay. Protein adsorption to the surfaces was also evaluated using immunofluorescence and immunohistochemistry techniques.

The thermoresponsive behavior of the P4VP brushes allowed for spontaneous detachment of ARPE-19 cell sheets upon cooling of the samples, with post-detachment observations confirming viability of the released cells.

In conclusion, our findings demonstrate the potential of P4VP brushes with CuNPs as effective platforms for cell sheet engineering. Therefore, these biocompatible, antibacterial, thermoresponsive coatings show promise for use in therapeutic applications.

The study was funded by the “Research support module” as part of the “Excellence Initiative - Research University” program at the Jagiellonian University in Kraków the (RSM/80/CA).

Supramolecular polymer structures are formed through reversible bonds between their components, enabling the production of materials with properties sensitive to external stimuli, such as pH, temperature, or light. One example of such materials is supramolecular hydrogels, which are used in our research and can be produced from simple and inexpensive ingredients, such as poly(vinyl alcohol) with quercetin (Q) [1]. The antibacterial and antifungal effects are attributed to the presence of Q in the hydrogel matrix. These hydrogels were tested against four strains of bacteria and four strains of yeast, including strains resistant to commonly used antifungal drugs. Another example of supramolecular materials is microparticles designed to release active substances at targeted sites of lesions or infections. The spray-drying method was employed to produce microparticles capable of encapsulating live mycobacteria (Mycobacterium bovis BCG) and releasing them under pH conditions mimicking the stomach's acidic environment or the intestine's alkaline conditions [2]. Their biocompatibility was demonstrated in vitro and in vivo using a guinea pig model (Cavia porcellus). Such microparticles are planned to be used to treat Helicobacter pylori infection.

The research was financed by the National Science Center SONATA 18, UMO-2022/47/D/NZ7/01097.

To overcome the limitations and invasiveness of traditional wound closure,[1] biomedical adhesives are relevant alternatives. They should be biocompatible, bioresorbable and exhibit appropriate adhesion and deformation. They should also favor wound healing and tissue reconstruction.[2] Well known for its biological properties (compatibility, resorbability bacteriostaticity…),[3] chitosan appears as a prime-choice natural polycation; to form soft adhesives, it can be complexed with anionic polysaccharides (alginates, ALG or hyaluronic acid, HA), which are already used in materials for medical applications.[4]
Our systems are produced by polyelectrolyte complexation of chitosan and ALG/HA.[5] After preparing chitosan and ALG/HA solutions of high ionic strength, they are mixed into a homogenous solution. Using dialysis, the ionic strength is decreased, allowing the formation of interpolymer interactions. Thus, physical hydrogels based on complexes of a host polymer (chitosan) and a guest polymer (ALG or HA) were formulated through the variation of several parameters including degree of acetylation (DA) of chitosan, proportion of the polysaccharides, addition of nanoparticles and dialysis conditions (pH, salt concentration, addition of divalent ions).
The mechanical/rheological properties of materials formed with various formulations were characterized and a focus was made on the systems with lower values for the loss factor tan δ, while keeping high moduli: these formulations led to tacky materials; in-air and under-water adhesion of the obtained systems was measured. The influence of the chitosan DA, of the polyanion and of the formulation was evaluated. Chitosan and ALG/HA hydrogels were obtained with tunable mechanical properties, and adhesion properties comparable to those of chemically-modified systems.

Supramolecular (SM) polymers benefit from an intrinsic ability to respond to external stimuli by altering their mechanical behavior, making them attractive for applications such as healable materials and debonding-on-demand adhesives. [1] Here, we present a general systems approach to render SM materials stimuli-responsive, which consists of combining an SM polymer with auxiliary trigger molecules. When activated, these molecules disrupt the binding of the SM motif, thus influencing the material's structure and properties. In our first embodiment of this approach, we exploited an SM network based on the self-complementary hydrogen-bonding ureidopyrimidinone (UPy) motif,[2] which is responsive to changes in temperature[3] and proton concentration.[4] To render UPy-based materials responsive to light – which can be applied remotely and locally – a system was created by blending a UPy-crosslinked SM polymer with a photoacid generator (PAG), which produces hydrochloric acid when irradiated with UV light.[5] We first confirmed the viability of this systems approach by demonstrating, through small molecule photoluminescence studies on pyrene-tagged UPy motifs, [4] that the optical activation of the PAG causes the protonation and disassembly of UPy dimers. Moving to polymeric systems, we used small-angle oscillatory shear rheology and Fourier transform infrared spectroscopy to show that the activation of the PAG causes solid-to-liquid transitions in organogels and solid films based on supramolecular networks in which UPy dimers serve as cross-links. Finally, we demonstrate proof-of-concept experiments that illustrate the potential application of such systems as debonding-on-demand adhesives.