ABSTRACT
While the construction of a donor-acceptor (D-A) structure has gained great attention across various scientific disciplines, such structures are seldomly reported within the field of hydrogen-bonded organic frameworks (HOFs). Herein, a D-A based HOF is synthesized, where the adjacent D-A pairs are connected by hydrogen bonds instead of the conventionally employed covalent bonds. This structural feature imparts material with a reduced energy gap between excited state and triplet state, thereby facilitating the intersystem crossing (ISC) and boosting the generation rate of single oxygen (quantum yield = 0.98). Consequently, the resulting material shows high performance for antimicrobial photodynamic therapy (PDT). The impact of D-A moiety is evident when comparing this finding to a parallel study conducted on an isoreticular HOF without a D-A structure. The study presented here provides in-depth insights into the photophysical properties of D-A pair in a hydrogen-bonded network, opening a new avenue to the design of innovative materials for efficient PDT.
ABSTRACT
OBJECTIVE: To observe the effect of acupotomy intervention on the expressions of biglycan(BGN), decorin(DCN) and Caspase-3 in lumbar intervertebral disc of rabbits with lumbar intervertebral disc degeneration (LIDD), so as to explore its possible mechanism in relieving LIDD. METHODS: Thirty male Japanese white rabbits were randomly divided into normal, model and acupotomy groups, with 10 rabbits in each group. The LIDD model was established by axial compression method, and magnetic resonance imaging (MRI) was used to judge whether the model was successful or not. After modeling, the acupotomy was applied to lumbar (L)4-L5 spinous process space and bilateral transverse processes for loosening, twice a week for 4 weeks. The structural changes of L4-L5 intervertebral disc were observed by MRI. The morphological changes of lumbar spine were observed by HE staining. The expression of Caspase-3 in nucleus pulposus was observed by immunohistochemistry, and the protein expressions of DCN and BGN in intervertebral disc were detected by Western blot, separatively. RESULTS: After mode-ling, the rabbits showed slow movement, stiff back muscles with cords or nodules, the fibrous ring structure of lumbar intervertebral disc was disordered, the number of nucleus pulposus cells was reduced, and the signal intensity of L4-L5 intervertebral disc was decreased in the model group relevant to the normal group. At the same time, the expression of Caspase-3 in nucleus pulposus was increased significantly (P<0.05), and the expression levels of DCN and BGN in intervertebral disc were decreased significantly (P<0.05). After acupotomy treatment, the modeling induced slow movement, stiff back muscles and disordered structure of lumbar intervertebral disc were significantly improved. The number of nucleus pulposus cells was increased, the signal intensity of L4-L5 intervertebral disc was enhanced, the expression of Caspase-3 in nucleus pulposus was decreased significantly (P<0.05), and the expression levels of DCN and BGN in intervertebral disc were increased significantly (P<0.05) compared with the model group. CONCLUSION: Acupotomy intervention can inhibit cell apoptosis, reduce the degradation of extracellular matrix in nucleus pulposus of intervertebral disc, and restore the normal force balance and dynamic balance of lumbar spine, which may be one of its mechanisms underlying improving LIDD.
