The low utilization efficiency of pesticides exerts an
adverse
impact on the environment and human health. Polymer-related controlled-release
nanosized pesticide systems provide a promising and efficient way
to overcome the problem. In this work, a biodegradable and light-responsive
amphiphilic polymer was synthesized via 1,1,3,3-tetramethylguanidine-promoted
polyesterification under mild conditions (low temperature, no vacuum,
and no inert gas protection). We used this polymer to fabricate a
light-triggered controlled-release nanosized pesticide system. The
herbicide, 2,4-dichlorophenoxyacetic acid (2,4-D), was selected as
a model drug to show its potential as a controlled-release pesticide
system. It was found that the 2,4-D-loaded polymeric nanoparticles
were stable without the treatment of UV, while the release rate of
2,4-D from the nanoparticles gradually increased after treatment with
UV light. Pot trial showed that the 2,4-D-loaded polymer nanoparticles
showed a good herbicidal effect. Finally, toxicity studies suggested
that the polymer can reduce toxicity to nontarget organisms.
A synthetic route to prepare a poly(ethylene glycol) with a single cinnamaldehyde acetal unit in the polymer chain, was successfully established using a newly synthesized cinnamaldehyde acetal diethylene glycol (CADEG) as initiator. This HO-PEG(ca)-OH is non-toxic and would be degraded into a cinnamaldehyde and two PEG diols in acid environment. A whole polyethylene glycol based hydrogel was easily fabricated by thiol-ene “click” reaction in alkalescence aqueous solution using acrylate-PEG(ca)-acrylate and 4-arm PEG-SH as raw materials at room temperature. The gel time was dependent on the pH of the solution and its alkalinity can promote gel. The hydrogel can be degradable in acidic conditions and the stronger the acidity, the faster the degradation. This HO-PEG(ca)-OH also can be used in synthesis of cinnamaldehyde containing PEG derivatives, block copolymers or other acid degradable materials.
Introducing desired functionalities into biomaterials is an effective way to obtain functionalized biomaterials. A versatile platform with the possibility of postsynthesis functionalization is highly desired but challenging in biomedical engineering. In this work, linear aliphatic polyesters with pendant hydroxyl (PEOH) groups were directly synthesized using renewable malic acid/ tartaric acid as raw materials under mild conditions through the polyesterification reaction promoted by 1,1,3,3-tetramethylguanidine (TMG). The hydroxyl groups on PEOH provide an active stepping stone for the fabrication of demanded functionalized polyesters. We demonstrated the possibility of the PEOH as a reactive precursor for functional group transformation, coupling of bioactive molecules, and formation of crosslinking networks. Moreover, a theranostic nanoplatform (mPEG-b-(P7-asp&TPV)-b-mPEG NPs) was synthesized using PEOH as a reactive stepping stone by the programmable combination of the above functionalization methods. Overall, these hydroxyl-containing polyesters have great potential in biological applications.
An o-nitrobenzyl dithiol and a group of diacrylates containing one or two functional groups were designed for facile synthesis of a series of linear photo-labile functional and heterobifunctional poly(β-thioester)s via thiol-ene click polymerization. These o-nitrobenzyl thioether-containing polyesters show excellent photo-degradation properties under UV light. Photoresponsive polymeric nanoparticles from a functional polyester exhibit good weeding performance as a herbicide delivery system. The possible photo-degradation mechanism of the polyesters was studied and proposed. The o-nitrobenzyl dithiol and its corresponding photo-labile polyesters could be used in smart drug or pesticide delivery, photo-labile graft copolymers synthesis, and even photolithography.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.