Understanding multicomponent low molecular weight gels from gelators to networks

Abstract

Background: The construction of gels from low molecular weight gelators (LMWG) has been extensively studied in the fields of bio-nanotechnology and other fields. However, the understanding gaps still prevent the prediction of LMWG from the full design of those gel systems. Gels with multicomponent become even more complicated because of the multiple interference effects coexist in the composite gel systems.

Aim of review: This review emphasizes systems view on the understanding of multicomponent low molecular weight gels (MLMWGs), and summarizes recent progress on the construction of desired networks of MLMWGs, including self-sorting and co-assembly, as well as the challenges and approaches to understanding MLMWGs, with the hope that the opportunities from natural products and peptides can speed up the understanding process and close the gaps between the design and prediction of structures.

Key scientific concepts of review: This review is focused on three key concepts. Firstly, understanding the complicated multicomponent gels systems requires a systems perspective on MLMWGs. Secondly, several protocols can be applied to control self-sorting and co-assembly behaviors in those multicomponent gels system, including the certain complementary structures, chirality inducing and dynamic control. Thirdly, the discussion is anchored in challenges and strategies of understanding MLMWGs, and some examples are provided for the understanding of multicomponent gels constructed from small natural products and subtle designed short peptides.

Keywords: Co-assembly; Low molecular weight gelators; Multicomponent; Self-sorting; Systems chemistry.

Graphical abstract

Fig. 1

Schematic illustration of multicomponent self-assemblies. During the formation of networks, the gelators have the ability to i) co-assemble to fibers in a completely random manner, or the components may have a slight tendency to interact with themselves, leading to the formation of blocks of each component, or the components may arrange themselves in an ordered pattern; ii) self-sort to form individually fibers that can either interact with each other or form independent interpenetrating networks. The entanglements within these networks might occur randomly or exhibit a preference for entangling certain segments of the main fibers. Reprinted with permission from . Copyright © 2023 The Authors. Published by The Royal Society of Chemistry.

Fig. 2

The chemical structures of PA-E3 and DBS-COOH .

Fig. 3

The chemical structures of chirality induced self-assemblies of trans-1,2-disubstituted cyclohexane derivatives and the schematic illustrations. Reprinted with permission from . Copyright © 2019 American Chemical Society.

Fig. 4

(a) The chemical structures of the multicomponent hydrogelators based on hydrazine; (b) schematic diagram of different multi-level self-sorting assembly pathways. Reprinted with permission from . Copyright © 2020 The Authors. Published by WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

Fig. 5

The chemical structures of the 12 molecules with various alkyl chain lengths .

Fig. 6

Some represented structures of natural LMWGs. Reprinted with permission from . Copyright © 2022 American Chemical Society.

Fig. 7

Schematic illustration of multicomponent self-assemblies based on the Berberine (BBR)-Organic acids . © 2022 The Authors. Published by Elsevier B.V.

Fig. 8

Different pH conditions show different assembly systems (from self-sorting to co-assembly). Reprinted with permission from . Copyright © 2021 The Authors. Published by Wiley-VCH GmbH.

Fig. 9

The chemical structures of LPF and LPFEG (middle); the selected SEM images of LPF and LPFEG hydrogels (left) and the mixed two-component hydrogels (right) .