Precision Polymers for Pharmaceutics
Field of Research
Our group is located at the interface of polymer chemistry and pharmaceutical sciences. We are focusing on the design of innovative drug delivery systems using sustainable and intelligent materials. These systems are based on intelligent, bio-based or biodegradable polymers that are synthesized using sophisticated polymerization techniques. These techniques include radical systems and metal-organic based catalysts. We develop tailor-made and advanced catalysts and monomers to meet the special needs for each specific pharmaceutical application.
Our research topics include:
- Ring-Opening Polymerization of Biobased Monomers
- Cationic Polymers for Ocular Gene Delivery
- pH-Responsible Polymers for Drug and Gene Delivery Applications
- Poly(vinylphosphonate)-based Therapeutics
In the last decades, group-transfer polymerization (GTP) and especially REM-GTP have proven to give access to a plethora of tailor-made homo- and copolymers based on α,β-unsaturated monomers. Thereby, GTP has established its potential in the development of functional and smart polymers.In our group, rare-earth metal-mediated GTP (REM-GTP) was established with nonmetallocene lanthanides as a multifunctional method for the efficient synthesis of high-precision polymers with variable tacticity, controllable molecular weights, and narrow molar mass distributions.
Using phosphorus-containing, cationic polymers synthesized by REM-GTP, novel siRNA delivery agents were developed that demonstrate excellent siRNA encapsulation, efficient endosomal escape, and effective gene silencing, while showing low cytotoxicity.
Paper Highlights:
Weingarten, P.; Lin, M. T.-Y.; Kränzlein, M.; Fietz, A.; Kachel, I.; Hurst, J.; Schnichels, S.; Adams, F. Phosphorous-containing, amphiphilic ABB′ copolymers as siRNA nanocarriers with enhanced stability, reduced in vitro cytotoxicity, and efficient knockdown ability for the treatment of ocular diseases. RSC Applied Polymers 2025, 3 (2), 381–390. DOI: 10.1039/d4lp00321g.
Coordination ring-opening polymerization (ROP) is considered to be the classic or conventional way for lactone polymerization. Studies have led to a variety of metal-based catalysts which are still unmatched in terms of controlled polymerization conditions. Especially, the possibility to tailor catalysts provides a toolbox for different thermodynamic circumstances or the stereoselective synthesis of functional materials.
Paper Highlights:
Hornberger, L.-S.; Hiotidis, S.; Jain, S.; Benz, M.; Montan, H.; Estes, D. P.; Kästner, J.; Adams, F. Influence of the Substitution Pattern of Terpene-Based Seven-Membered Lactones on Yttrium-Mediated Ring-Opening Polymerization: A Kinetic and Mechanistic Investigation. Chem. Eur. J. 2025, 31 (38), e202501380. DOI: https://doi.org/10.1002/chem.202501380.
Hornberger, L.-S.; Fischer, J.; Friedly, A.; Hartenbach, I.; Sottmann, T.; Adams, F. Yttrium-mediated ring-opening polymerization of functionalizable dihydrocarvide: tunable terpene-based polyesters using grafting from and block copolymerization strategies. Polym. Chem. 2025, 16 (25), 2910–2922. DOI: 10.1039/D5PY00322A.
Hornberger, L.-S.; Weingarten, P.; Lange, P. L.; Schleid, T.; Adams, F. Connecting 16- with 4-Membered Rings: Ring-Opening Polymerization of Bio-Based ω-Pentadecalactone with Amino-Alkoxy-Bis(phenolate) Yttrium Initiators and Copolymerization with β-Butyrolactone. European Polymer Journal 2023, 199, 112449. DOI: 10.1016/j.eurpolymj.2023.112449.
The availability of polymerization methods facilitating a precise synthesis of polymers with controllable molecular weights, narrow molecular weight distributions, precise block copolymer formation and variable end groups is a basic prerequisite for establishing polymers for gene and drug therapy. Such polymers can be synthesized efficiently and tailor-made using radical polymerization techniques such as atom transfer radical polymerization (ATRP).
Paper Highlights:
Weingarten, P.; Adams, F. Silver-Mediated ARGET-ATRP of Reactive Acrylates Using TPMA(NMe2) Ligand: A Universal Strategy for Controlled Copolymerization. ACS Macro Lett 2024, 13 (10), 1318–1324. DOI: 10.1021/acsmacrolett.4c0062.
Post-polymerization functionalization is a critical tool in preparing functional materials. Functionalization is performed after a non-functionalized polymer was synthesized. One of the most common ways in our lab to attach functionality onto a preexisting polymer backbone is through active ester groups, click reactions and thiol-ene reaction. In addition, we use precise end-groups from polymers synthesized via living routes for further functionalization.
Paper Highlights:
Weingarten, P.; Lin, M. T.-Y.; Kränzlein, M.; Fietz, A.; Kachel, I.; Hurst, J.; Schnichels, S.; Adams, F. Phosphorous-containing, amphiphilic ABB′ copolymers as siRNA nanocarriers with enhanced stability, reduced in vitro cytotoxicity, and efficient knockdown ability for the treatment of ocular diseases. RSC Applied Polymers 2025, 3 (2), 381–390. DOI: 10.1039/d4lp00321g.
Adams, F.; Zimmermann, C. M.; Baldassi, D.; Pehl, T. M.; Weingarten, P.; Kachel, I.; Kranzlein, M.; Jurgens, D. C.; Braubach, P.; Alexopoulos, I.; et al. Pulmonary siRNA Delivery with Sophisticated Amphiphilic Poly(Spermine Acrylamides) for the Treatment of Lung Fibrosis. Small 2024, 20 (22), e2308775. DOI: 10.1002/smll.202308775.
Hornberger, L.-S.; Fischer, J.; Friedly, A.; Hartenbach, I.; Sottmann, T.; Adams, F. Yttrium-mediated ring-opening polymerization of functionalizable dihydrocarvide: tunable terpene-based polyesters using grafting from and block copolymerization strategies. Polym. Chem. 2025, 16 (25), 2910–2922. DOI: 10.1039/D5PY00322A.
Adams, F. Merging sigma-Bond Metathesis with Polymerization Catalysis: Insights into Rare-Earth Metal Complexes, End-Group Functionalization, and Application Prospects. Macromol Rapid Commun 2024, 45 (15), e2400122. DOI: 10.1002/marc.202400122.
Polymeric nanocarriers can easily be tailored with respect to size, chemical composition, shape, and surface properties. These carriers increase the solubility and protect the therapeutic agents against harsh biological conditions, and allow for controlled and targeted release of elevated dosages, which reduces off-target toxicity. Furthermore, as drug carriers, polymeric micelles should be stable at low concentrations, which enables long in vivo circulation times and inhibits premature drug release. In addition, thermoresponsive or pH-sensitive triggers of multiresponsive polymers can be used to further enhance these systems as drug delivery carrier.
In general, nucleic acids show a high affinity towards cationic polymers due to electrostatic interactions to form so called polyplexes. Amine-containing polymers are positively charged at physiological pH and are therefore commonly used for RNA delivery. Our research focusses on the design of brushed poly(acrylamide) and poly(acrylates) with polyamine pendant groups.
Paper Highlights:
Adams, F.; Zimmermann, C. M.; Baldassi, D.; Pehl, T. M.; Weingarten, P.; Kachel, I.; Kranzlein, M.; Jurgens, D. C.; Braubach, P.; Alexopoulos, I.; et al. Pulmonary siRNA Delivery with Sophisticated Amphiphilic Poly(Spermine Acrylamides) for the Treatment of Lung Fibrosis. Small 2024, 20 (22), e2308775. DOI: 10.1002/smll.202308775.
Weingarten, P.; Lin, M. T.-Y.; Kränzlein, M.; Fietz, A.; Kachel, I.; Hurst, J.; Schnichels, S.; Adams, F. Phosphorous-containing, amphiphilic ABB′ copolymers as siRNA nanocarriers with enhanced stability, reduced in vitro cytotoxicity, and efficient knockdown ability for the treatment of ocular diseases. RSC Applied Polymers 2025, 3 (2), 381–390. DOI: 10.1039/d4lp00321g.
Pourdakheli Hamedani, Y.; Hurst, J.; Ritter, M.; Weingarten, P.; Skokowa, J.; Schnichels, S.; Adams, F. Ex Vivo Evaluation of Poly(Solketal Acrylate) Nanoparticles for Intravitreal Drug Delivery to the Posterior Eye Segment. Macromol Rapid Commun 2025, e00788. DOI: 10.1002/marc.202500788.
Hurst, J.; Adams, F.; Schnichels, S. The Future of Nanomaterials Tackling the Challenge of Delivering Nucleic Acids to the Retina. Advanced Functional Materials 2025, 35 (3), 2407173. DOI: https://doi.org/10.1002/adfm.202407173.