Biomineralization is an important tactic by which biological organisms produce hierarchically structured minerals with marvellous functions. Biomineralization studies typically focus on the mediation function of organic matrices on inorganic minerals, which helps scientists to design and synthesize bioinspired functional materials. However, the presence of inorganic minerals may also alter the native behaviours of organic matrices and even biological organisms. This progress report discusses the latest achievements relating to biomineralization mechanisms, the manufacturing of biomimetic materials and relevant applications in biological and biomedical fields. In particular, biomineralized vaccines and algae with improved thermostability and photosynthesis, respectively, demonstrate that biomineralization is a strategy for organism evolution via the rational design of organism-material complexes. The successful modification of biological systems using materials is based on the regulatory effect of inorganic materials on organic organisms, which is another aspect of biomineralization control. Unlike previous studies, this study integrates materials and biological science to achieve a more comprehensive view of the mechanisms and applications of biomineralization.

Epithelial ovarian cancer (EOC) is a highly lethal gynaecological malignancy. Cisplatin is the basal chemotherapeutic agent used to treat EOC, but resistance to cisplatin leads to chemotherapy failure. MicroRNAs are a novel class of regulators that function by controlling gene expression at the post-transcriptional level. Several recent reports have identified some microRNAs that are related to chemotherapy sensitivity. In this study, we found two microRNAs miR-152 and miR-185 that were significantly downregulated in the cisplatin-resistant ovarian cell lines SKOV3/DDP and A2780/DDP, compared with their sensitive parent line SKOV3 and A2780, respectively. Subsequently, the roles of miR-152 and miR-185 were evaluated in vitro and in vivo. The overexpression of miR-152 or miR-185 increased cisplatin sensitivity of SKOV3/DDP and A2780/DDP cells by inhibiting proliferation and promoting apoptosis, then we further confirmed that these miRNAs functioned through suppressing DNA methyltransferase 1 (DNMT1) directly. Concordantly, CD-1/CD-1 nude mice that were injected intraperitoneally with SKOV3/DDP cells transfected with miR-152 mimics exhibited upregulated cisplatin sensitivity in vivo. Interestingly, we found that there were no significant changes in the expression of these two microRNAs after treatment with decitabine (DAC), a traditional epigenetic therapeutic agent, suggesting these miRNAs represented two new regulators independent of DAC. Finally, the survival assay in A549 and HepG2 cells revealed that the two microRNAs involved in cisplatin sensitivity were related to cell types. Our results indicated that miR-152 and miR-185 were involved in ovarian cancer cisplatin resistance in vitro and in vivo by targeting DNMT1 directly. These molecules may serve as potential epigenetic therapeutic targets in other cancers.

Biological hard tissues such as bones always contain extremely high levels of citrate, which is believed to play an important role in bone formation as well as in osteoporosis treatments. However, its mechanism on biomineralization is not elucidated. Here, it is found that the adsorbed citrate molecules on collagen fibrils can significantly reduce the interfacial energy between the biological matrix and the amorphous calcium phosphate precursor to enhance their wetting effect at the early biomineralization stage, sequentially facilitating the intrafibrillar formation of hydroxyapatite to produce an inorganic-organic composite. It is demonstrated experimentally that only collagen fibrils containing ≈8.2 wt% of bound citrate (close to the level in biological bone) can reach the full mineralization as those in natural bones. The effect of citrate on the promotion of the collagen mineralization degree is also confirmed by in vitro dentin repair. This finding demonstrates the importance of interfacial controls in biomineralization and more generally, provides a physicochemical view about the regulation effect of small biomolecules on the biomineralization front.

Evidence for sexual dimorphism in autonomic control of cardiovascular function is both compelling and confounding. Across healthy and disease populations sex-associated differences in neurocirculatory hemodynamics are far too complex to be entirely related to sex hormones. As an initial step toward identifying additional physiological mechanisms, we investigated whether there is a sex bias in the relative expression of low-threshold-myelinated and high-threshold-unmyelinated aortic baroreceptor afferents in rats. These two types of afferent fibers have markedly different reflexogenic effects upon heart rate and blood pressure and thus the potential impact upon baroreflex dynamics could be substantial. Our results, using a combination of a patch-clamp study of fluorescently identified aortic baroreceptor neurons (ABN) and morphometric analysis of aortic baroreceptor nerve fibers, demonstrate that females exhibit a greater percentage of myelinated baroreceptor fibers (24.8% vs. 18.7% of total baroreceptor fiber population, P < 0.01) and express a functional subtype of myelinated ABN rarely found in age-matched males (11% vs. 2.3%, n = 107, P < 0.01). Interestingly, this neuronal phenotype is more prevalent in the general population of female vagal afferent neurons (17.7% vs. 3.8%, n = 169, P < 0.01), and ovariectomy does not alter its expression but does lessen neuronal excitability. These data suggest there are fundamental neuroanatomical and electrophysiological differences between aortic baroreceptor afferents of female and male rats. Possible explanations are presented as to how such a greater prevalence of low-threshold myelinated afferents could be a contributing factor to the altered baroreflex sensitivity and vagal tone of females compared with males.

Herein, we propose a drug-free approach to cancer therapy that involves cancer cell targeting calcification (CCTC). Several types of cancer cells, such as HeLa cells, characterized by folate receptor (FR) overexpression, can selectively adsorb folate (FA) molecules and then concentrate Ca(2+) locally to induce specific cell calcification. The resultant calcium mineral encapsulates the cancer cells, inducing their death, and in vivo assessments confirm that CCTC treatment can efficiently inhibit tumor growth and metastasis without damaging normal cells compared with conventional chemotherapy. Accordingly, CCTC remarkably improve the survival rate of tumor mice. Notably, both FA and calcium ions are essential ingredients in human metabolism, which means that CCTC is a successful drug-free method for tumor therapy. This achievement may further represent an alternative cancer therapy characterized by selective calcification-based substitution of sclerosis for tumor disease.