Computational methods complement experiments in chemistry? The new reality in everyday laboratory work

The progress of molecular modelling holds significant promise, thanks to advancements in computational software and hardware. Calculation methods are important to reduce the cost of using chemicals, thus protecting the environment. Also, it helps investigate the details that lead to better experimental results.

This is highlighted by scientists from the Center for Physical Sciences and Technology (FTMC), one of the largest research institutes in the Baltic states. One of its scientific divisions is the Department of Nanotechnology, whose researchers work on MIP technology.

Molecularly imprinted polymers (MIP) are artificial receptors with tailor-made binding sites for specific target molecule recognition. "MIPs are used in sensor design, chemical extraction, catalysis, drug delivery systems, etc," explains Prof. habil. Dr. Arūnas Ramanavičius, Head of FTMC Department of Nanotechnology.

The stepwise MIP fabrication process includes (1) the selection of optimal polymerisation reagents, (2) polymerisation, (3) extraction of template molecules from the polymer film, and (4) target molecules rebinding on the MIP. A functional polymer film comprising binding sites or complementary cavities is created in this process. This allows us to identify the target molecules and distinguish them from possible interfering compounds.

"The choice of reagents and methods impacts the MIP performance. The usual MIP preparation process requires too much experimentation, which is time-consuming, expensive and environmentally harmful due to the toxicity of released chemicals," describes FTMC chemist Dr. Vilma Ratautaitė.

However, she adds, the optimal conditions study is crucial to achieve the essential MIP selectivity and sensitivity. The lengthy process of MIP synthesis can increase costs and release large amounts of toxic materials. This can have dangerous effects on the environment. Therefore, computational methods have found their extensive application and have been widely used. This is a big step towards green chemistry methods that make it feasible to minimise the need for experiments.

Computational methods pave the way for smarter design of MIPs and lead to better experiment results. Host-guest chemistry is about receptor molecules (host, which is usually a larger molecule) binding to another molecule named ligand (guest, which is usually a smaller molecule). The host-guest chemistry study in MIPs via computational methods brings tools to delve into the details implausible with experiments.

Such methods as atomistic simulations (Molecular Dynamics (MD), molecular docking, Monte Carlo) and quantum mechanical calculations (Density Functional Theory (DFT), Hartree-Fock) are widely used for the design of MIP.

"Due to their applicability to any MIP preparation step, computational methods have gained considerable attention. The selection of optimal functional monomer(s), crosslinker, solvent or the study of MIP interactions with the target are the most commonly evaluated by computational methods," illustrates FTMC Ph.D. student Enayat Mohsenzadeh.

This modelling provides calculation of binding free energies, solvent effects, thermodynamics parameters of the system, conformation changes and study of interactions. Thus, this invaluable information is used to design a more advanced MIP with lower expenses and chemical use. They also provide a deeper insight into the details of the host-guest molecular system.

According to E. Mohsenzadeh, there is great potential for MIP modelling development due to the emerging computational software and hardware. Therefore, on one side, an essential need to achieve optimised conditions and on the other side, expenses and environmental concerns emphasise the significance of computational methods in MIP development.

Provided by Center for Physical Sciences and Technology