Direct Synthesis of Aliphatic Polyesters with Pendant Hydroxyl Groups from Bio-Renewable Monomers: A Reactive Precursor for Functionalized Biomaterials.

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.

Non-invasive auditory and visual stimulation attenuates α-Synuclein deposition and improves motor and non-motor symptoms in PD mice.

Parkinson's disease (PD) is characterized by dopaminergic neuron loss and α-synuclein (α-Syn) aggregates, but lacks effective treatments for the disease progression and non-motor symptoms. Recently, combined 40 Hz auditory and visual stimulation is emerging as a promising non-invasive method to decrease amyloid and improve cognition in Alzheimer's disease (AD), but whether this treatment can modify α-Syn-induced PD pathology remains unclear. Here we evaluated the effects of chronic exposure to 40 Hz and 80 Hz auditory and visual stimulation on α-Syn accumulation and the functional effects of 40 Hz stimulation on motor, cognitive and mood dysfunctions in PD mice. We found that 40 Hz and 80 Hz auditory and visual stimulation activated multiple cortical regions, entrained gamma oscillations and markedly attenuated p-α-Syn deposition in neurons, but not astrocytes, microglial cells in the primary and secondary motor cortex (M1, M2), medial prefrontal cortex (mPFC) and the striatum. Moreover, 40 Hz stimulation significantly reduced cell apoptosis in M1, increased the neuromuscular strength selectively in PD mice, which correlated with p-α-Syn reduction in the motor cortex. In addition, 40 Hz stimulation improved spatial working memory and decreased depressive-like behaviors specifically in PD mice, which correlated with p-α-Syn reduction in mPFC, but promoted anxiety-like behaviors and increased stress-related adreno-cortico-tropic-hormone (ACTH), corticosterone levels in the plasma of normal mice. Collectively, we demonstrated that chronic multisensory gamma stimulation (40 Hz and 80 Hz) significantly attenuates α-Syn deposition in neurons of the interconnected cortex and 40 Hz stimulation improved neuromuscular strength, spatial working memory, and reduced depressive behaviors, which support its non-invasive therapeutic potential for modifying PD progression and treating non-motor symptoms.

Biodegradable and Light-Responsive Polymeric Nanoparticles for Environmentally Safe Herbicide Delivery.

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.