More Like this

1. Tuning Microbial Activity via Programmatic Alteration of Cell/Substrate Interfaces

   https://doi.org/10.1002/adma.202004655  

   Gulyuk, Alexey_V; LaJeunesse, Dennis_R; Collazo, Ramon; Ivanisevic, Albena (May 2021, Advanced Materials)

   Abstract A wide portfolio of advanced programmable materials and structures has been developed for biological applications in the last two decades. Particularly, due to their unique properties, semiconducting materials have been utilized in areas of biocomputing, implantable electronics, and healthcare. As a new concept of such programmable material design, biointerfaces based on inorganic semiconducting materials as substrates introduce unconventional paths for bioinformatics and biosensing. In particular, understanding how the properties of a substrate can alter microbial biofilm behavior enables researchers to better characterize and thus create programmable biointerfaces with necessary characteristics on demand. Herein, the current status of advanced microorganism–inorganic biointerfaces is summarized along with types of responses that can be observed in such hybrid systems. This work identifies promising inorganic material types along with target microorganisms that will be critical for future research on programmable biointerfacial structures. 

   more » « less
2. Everything You Want to Know About Coarse‐Graining and Never Dared to Ask: Macromolecules as a Key Example

   https://doi.org/10.1002/wcms.70022  

   Guenza, Marina_G (April 2025, WIREs Computational Molecular Science)

   ABSTRACT Coarse‐graining (CG) is transforming the study of molecular systems, allowing researchers to explore by computer simulations larger and more complex structures than ever before. Continued advancements in CG techniques are making simulations more efficient, establishing this approach as a cornerstone for designing innovative materials and eco‐friendly alternatives to traditional plastics. Additionally, CG methods are becoming indispensable for unraveling the complexities and functional mechanisms of large‐scale macromolecular machines within cells. Yet, crafting an effective coarse‐grained model demands a nuanced understanding of its advantages and limitations. Faster simulations come at the cost of molecular detail and accuracy in some properties, so that it is essential to balance computational efficiency with the specific needs of the system one wants to simulate. By asking the right questions, researchers can select models that offer the desired benefits while managing trade‐offs. This article delves into the potential of different CG models and the compromises inherent in their adoption, highlighting their role in shaping the future of material science and biophysics. 

   more » « less
3. Investigating the energetic and entropic components of effective potentials across a glass transition

   https://doi.org/10.1088/1361-648X/abdff8  

   Szukalo, Ryan J.; Noid, W. G. (February 2021, Journal of Physics: Condensed Matter)

   Abstract By eliminating unnecessary details, coarse-grained (CG) models provide the necessary efficiency for simulating scales that are inaccessible to higher resolution models. However, because they average over atomic details, the effective potentials governing CG degrees of freedom necessarily incorporate significant entropic contributions, which limit their transferability and complicate the treatment of thermodynamic properties. This work employs a dual-potential approach to consider the energetic and entropic contributions to effective interaction potentials for CG models. Specifically, we consider one- and three-site CG models for ortho-terphenyl (OTP) both above and below its glass transition. We employ the multiscale coarse-graining (MS-CG) variational principle to determine interaction potentials that accurately reproduce the structural properties of an all-atom (AA) model for OTP at each state point. We employ an energy-matching variational principle to determine an energy operator that accurately reproduces the intra- and inter-molecular energy of the AA model. While the MS-CG pair potentials are almost purely repulsive, the corresponding pair energy functions feature a pronounced minima that corresponds to contacting benzene rings. These energetic functions then determine an estimate for the entropic component of the MS-CG interaction potentials. These entropic functions accurately predict the MS-CG pair potentials across a wide range of liquid state points at constant density. Moreover, the entropic functions also predict pair potentials that quite accurately model the AA pair structure below the glass transition. Thus, the dual-potential approach appears a promising approach for modeling AA energetics, as well as for predicting the temperature-dependence of CG effective potentials. 

   more » « less
4. Accelerating atomistic simulations of proteins using multiscale enhanced sampling with independent tempering

   https://doi.org/10.1002/jcc.26461  

   Liu, Xiaorong; Gong, Xiping; Chen, Jianhan (December 2020, Journal of Computational Chemistry)

   Abstract Efficient sampling of the conformational space is essential for quantitative simulations of proteins. The multiscale enhanced sampling (MSES) method accelerates atomistic sampling by coupling it to a coarse‐grained (CG) simulation. Bias from coupling to the CG model is removed using Hamiltonian replica exchange, such that one could benefit simultaneously from the high accuracy of atomistic models and fast dynamics of CG ones. Here, we extend MSES to allow independent control of the effective temperatures of atomistic and CG simulations, by directly scaling the atomistic and CG Hamiltonians. The new algorithm, named MSES with independent tempering (MSES‐IT), supports more sophisticated Hamiltonian and temperature replica exchange protocols to further improve the sampling efficiency. Using a small but nontrivial β‐hairpin, we show that setting the effective temperature of CG model in all conditions to its melting temperature maximizes structural transition rates at the CG level and promotes more efficient replica exchange and diffusion in the condition space. As the result, MSES‐IT drive faster reversible transitions at the atomic level and leads to significant improvement in generating converged conformational ensembles compared to the original MSES scheme. 

   more » « less
5. A hybrid approach for coarse-graining helical peptoids: Solvation, secondary structure, and assembly

   https://doi.org/10.1063/5.0138510  

   Banerjee, Akash; Dutt, Meenakshi (March 2023, The Journal of Chemical Physics)

   Protein mimics such as peptoids form self-assembled nanostructures whose shape and function are governed by the side chain chemistry and secondary structure. Experiments have shown that a peptoid sequence with a helical secondary structure assembles into microspheres that are stable under various conditions. The conformation and organization of the peptoids within the assemblies remains unknown and is elucidated in this study via a hybrid, bottom-up coarse-graining approach. The resultant coarse-grained (CG) model preserves the chemical and structural details that are critical for capturing the secondary structure of the peptoid. The CG model accurately captures the overall conformation and solvation of the peptoids in an aqueous solution. Furthermore, the model resolves the assembly of multiple peptoids into a hemispherical aggregate that is in qualitative agreement with the corresponding results from experiments. The mildly hydrophilic peptoid residues are placed along the curved interface of the aggregate. The composition of the residues on the exterior of the aggregate is determined by two conformations adopted by the peptoid chains. Hence, the CG model simultaneously captures sequence-specific features and the assembly of a large number of peptoids. This multiscale, multiresolution coarse-graining approach could help in predicting the organization and packing of other tunable oligomeric sequences of relevance to biomedicine and electronics. 

   more » « less