Argentinian researchers have recently published a study in European Polymer Journal in which a precipitation approach was used to create dendritic thermo-responsive polymer-based NGs.
Study: Nanogels and dendritic molecules combined to form a smart nanomaterial. Image Credit: Photobank.kiev.ua/Shutterstock.com
Importance of Nanogels
The word nanogel (NG) was first coined in 1999. NGs are described as nanoparticles of any form with an equivalent diameter ranging from 1 to 100 nm. NGs have a cross-linked polymer structure and may expand by having a considerable volume of solvent, without dissolving, and still keeping the structure intact.
The advancement of research has resulted in the development of a diverse spectrum of NGs with varying properties owing to differences in size, shape, and surface features. Environmentally responsive or stimulus-sensitive NGs are especially intriguing.
These NGs have been dubbed "smart materials" because they may experience phase changes in the presence of minor changes in external factors like warmth, pressure, radiation, and electromagnetic fields.
Limitations of Nanogels
While nanogels have many advantages, they do have significant drawbacks that may restrict their application in particular circumstances. For nanogels, the complete overall removal of the solvent is achieved by very costly methods which incorporate the utilization of expensive equipment.
Along with this, their synthesis and utilization may be followed by traces of monomer particles which could be toxic. The manufacturing problems and challenges exist alongside the fact that nanogels can only be synthesized within a certain range of sizes.
The remodeling with dendrons or dendrimers offers up endless possibilities for working with dendritic NGs (dNGs), which have conjugated interactions. Dendritic/dendronized polymers are an intriguing and potential building component for the development of customized materials. It has been demonstrated that the dendritic material's behavior is controlled by the production, chemical structure, and size of the molecule.
Dendronization is widely implemented on biopolymers to synthesize modified hybrid substances including thin films and microspheres. Dendronization influences the topology and other surface features; hence, dendronization may be successfully employed to introduce certain qualities necessary for compound nanocarriers.
Keeping in mind all of these factors, the researchers have thoroughly studied and analyzed the dendronization of nanogels.
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This enables a hybrid combination of the impact of dendrons with the nano-particle dimensions of NGs. The inclusion of a dendron into NiPAm-based NGs was studied, as well as the physicochemical characteristics, thermal characteristics, and reactions to pH stimuli. The acquired smart NGs are innovative and intriguing platforms for a variety of applications.
The researchers synthesized two distinct dendrons. The synthesis of the NGs began with the creation of a thermosensitive homopolymer. The dendrons, either the acrylated dendron (ABA) or the hydrolyzed dendron, were then added to create different systems (ABC).
All NGs were prepared by precipitation polymerization. The polymeric NGs were created by changing the crosslinkers (BIS), monomer ratios, and dendritic moiety peripheral functional groups.
It was observed that the system is originally homogenous, but as the polymer chains develop, their absorption in water declines. With particles forming a dispersed phase, the system becomes heterogeneous. Within the dispersed phase, polymerization proceeds until the polymer reach the so-called "critical length," at which point polymerization is terminated.
The transition temperature decreases as the amount of BIS increases, regardless of the amount of dendron. This phenomenon might be explained by considering the fundamental basis (Brownian motion (BM)) upon which DLS measurements are based. The larger the size of the particle, the slower the BM.
The electron microscopy revealed that the size of nanogels was found to be around 43, 66, and 180 nm.
They are extremely useful in biological applications. Dendrites are similar to proteins, enzymes, and viruses in that they may be easily functionalized. Dendrimers and other molecules can be connected to the perimeter or contained in the internal voids of dendrimers.
Dendrimers have the most exciting potential as their ability to execute regulated and specific drug delivery, which is relevant to the issue of nanomedicine. Metal chelates based on dendrimers serve as contrast agents in magnetic resonance imaging (MRI).
Because of their features, dendrimers are ideal for use as image contrast media. Hence, Dendrimers have unique characteristics that make them suitable candidates for a wide range of applications.
To conclude, One-pot copolymerization of thermo-responsive PVCL polymers with the multipurpose dendron ABA and ABC resulted in intriguing and potentially smart NGs. As a consequence, low polydispersity NGs with varied Tcp values were generated.
Dendritic configurations have a synergistic effect on the structure/property connection. These nanoparticles would constitute a new class of smart biomaterials with enormous promise for future applications such as sensing and healthcare.
Rosso, A. P., & Martinelli, M. (2021). Nanogels and dendritic molecules combined to form a smart nanomaterial. European Polymer Journal https://www.sciencedirect.com/science/article/pii/S001430572100608X