Fabrication of ACP-CCS-PVA composite membrane for a potential application in guided bone regeneration.

The barrier membranes of guided bone regeneration (GBR) have been widely used in clinical medicine to repair bone defects. However, the unmatched mechanical strength, unsuitable degradation rates, and insufficient regeneration potential limit the application of the current barrier membranes. Here, amorphous calcium phosphate-carboxylated chitosan-polyvinyl alcohol (ACP-CCS-PVA) composite membranes are fabricated by freeze-thaw cycles, in which the ATP-stabilized ACP nanoparticles are uniformly distributed throughout the membranes. The mechanical performance and osteogenic properties are significantly improved by the ACP incorporated into the CCS-PVA system, but excess ACP would suppress cell proliferation and osteogenic differentiation. Our work highlights the pivotal role of ACP in GBR and provides insight into the need for biomaterial fabrication to balance mechanical strength and mineral content.

Promotion of collagen mineralization and dentin repair by succinates.

Biomineralization of collagen fibers is regulated by non-collagenous proteins and small biomolecules, which are essential in bone and teeth formation. In particular, small biomolecules such as succinic acid (SA) exist at a high level in hard tissues, but their role is yet unclear. Here, our work demonstrated that SA could significantly promote intrafibrillar mineralization in two- and three-dimensional collagen models, where the relative mineralization rate was 16 times faster than the control group. Furthermore, the FTIR spectra and isothermal experimental results showed that collagen molecules could interact with SA via a hydrogen bond and that the interaction energy was about 4.35 kJ mol-1. As expected, the SA-pretreated demineralized dentin obtained full remineralization within two days, whereas it took more than four days in the control group, and their mechanical properties were considerably enhanced compared with those of the demineralized one. The possible mechanism of the promotion effect of SA was ultimately illustrated, with SA modification strengthening the capacity of the collagen matrix to attract more calcium ions, which might create a higher local concentration that could accelerate the mineralization of collagen fibers. These findings not only advance the understanding of the vital role of small biomolecules in collagen biomineralization but also facilitate the development of an effective strategy to repair hard tissues.

Tannic acid induces dentin biomineralization by crosslinking and surface modification.

It is currently known that crosslinking agents can effectively improve the mechanical properties of dentin by crosslinking type I collagen. However, few scholars have focused on the influence of crosslinking agents on the collagen-mineral interface after crosslinking. Analysis of the Fourier transform infrared spectroscopy (FTIR) results showed that hydrogen bonding occurs between the tannic acid (TA) molecule and the collagen. The crosslinking degree of TA to collagen reached a maximum 41.28 ± 1.52. This study used TA crosslinked collagen fibers to successfully induce dentin biomineralization, and the complete remineralization was achieved within 4 days. The crosslinking effect of TA can improve the mechanical properties and anti-enzyme properties of dentin. The elastic modulus (mean and standard deviation) and hardness values of the remineralized dentin pretreated with TA reached 19.1 ± 1.12 GPa and 0.68 ± 0.06 GPa, respectively, which were close to those of healthy dentin measurements, but significantly higher than those of dentin without crosslinking (8.91 ± 1.82 GPa and 0.16 ± 0.01 GPa). The interface energy between the surface of collagen fibers and minerals decreased from 10.59 mJ m-2 to 4.19 mJ m-2 with the influence of TA. The current work reveals the importance of tannic acid crosslinking for dentin remineralization while providing profound insights into the interfacial control of biomolecules in collagen mineralization.

Effect of Chinese herbal medicine on serum lipids in postmenopausal women with mild dyslipidemia: a randomized, placebo-controlled clinical trial.

OBJECTIVE: Previous studies have shown the association between menopause and dyslipidemia. This study was aimed to evaluate the effect of Chinese herbal medicine, tonifying kidney and descending turbidity (TKDT) granule, on serum lipid profiles in postmenopausal women with dyslipidemia. METHODS: A double-blind randomized, placebo-controlled trial was conducted among 104 postmenopausal Chinese women with mild dyslipidemia. Participants were randomized into treatment group (n = 53) and control group (n = 51). The participants in the treatment group received TKDT granule once per day for 24 weeks, whereas the control group received placebo in the same manner. All participants were subjected to healthy lifestyle during the study. Serum lipid profiles, body weight, waist circumference, and safety indicators were measured both at baseline and 24 weeks after admission. RESULTS: Compared with placebo, significant improvements in total cholesterol, low-density lipoprotein cholesterol, apolipoprotein-B (Apo-B), weight, and waist circumference in the TKDT group (P < 0.05) were observed after 24 weeks of treatment. Total cholesterol, low-density lipoprotein cholesterol, and Apo-B were decreased by 0.84 (0.77) mmol/L, 0.72 (0.77) mmol/L, and 0.12 (0.27) mmol/L, mean ±â€ŠSD respectively. The weight, waist circumference, and body mass index were decreased by 4.07 (3.01) kg, 3.10 (2.95) cm, 1.60 (1.13), respectively. There were no significant differences in triglycerides, high-density lipoprotein cholesterol, and Apo-A between the two groups. Seven participants in the treatment group and six participants in the placebo group had mild or moderate adverse reactions. CONCLUSION: TKDT granule improved the lipid profile and reduced the related metabolic abnormalities in postmenopausal women with mild dyslipidemia based on lifestyle changes.

Polydopamine Promotes Dentin Remineralization via Interfacial Control.

Biomineralization has intrigued researchers for decades. Although mineralization of type I collagen has been universally investigated, this process remains a great challenge due to the lack of mechanistic understanding of the roles of biomolecules. In our study, dentine was successfully repaired using the biomolecule polydopamine (PDA), and the remineralized dentine exhibited mechanical properties comparable to those of natural dentine. Detailed analyses of the collagen mineralization process facilitated by PDA showed that PDA can promote intrafibrillar mineralization with a decreased heterogeneous nucleation barrier for hydroxyapatite (HAP) by reducing the interfacial energy between collagen fibrils and amorphous calcium phosphate (ACP), resulting in the conversion of an increasing amount of nanoprecursors into collagen fibrils. The present work highlights the importance of interfacial control in dentine remineralization and provides profound insight into the regulatory effect of biomolecules in collagen mineralization as well as the clinical application of dentine restoration.