Human Perinatal‐Derived Biomaterials

Epigenetic plasticity in relation to in utero exposures may mechanistically explain observed differences in the likelihood of developing common complex diseases including hypertension, diabetes and cardiovascular disease through the cumulative effects of subtle alterations in gene expression. Imprinted genes are essential mediators of growth and development and are characterized by differentially methylated regulatory regions (DMRs) that carry parental allele-specific methylation profiles. This theoretical 50% level of methylation provides a baseline from which endogenously- or exogenously-induced deviations in methylation can be detected. We quantified DNA methylation at imprinted gene DMRs in a large panel of human conceptal tissues, in matched buccal cell specimens collected at birth and at one year of age, and in the major cell fractions of umbilical cord blood to assess the stability of methylation at these regions. DNA methylation was measured using validated pyrosequencing assays at seven DMRs regulating the IGF2/H19, DLK1/MEG3, MEST, NNAT and SGCE/PEG10 imprinted domains. DMR methylation did not significantly differ for the H19, MEST and SGCE/PEG10 DMRs across all conceptal tissues analyzed (ANOVA p>0.10). Methylation differences at several DMRs were observed in tissues from brain (IGF2 and MEG3-IG DMRs), liver (IGF2 and MEG3 DMRs) and placenta (both DLK1/MEG3 DMRs and NNAT DMR). In most infants, methylation profiles in buccal cells at birth and at one year of age were comparable, as was methylation in the major cell fractions of umbilical cord blood. Several infants showed temporal deviations in methylation at multiple DMRs. Similarity of inter-individual and intra-individual methylation at some, but not all of the DMRs analyzed supports the possibility that methylation of these regions can serve as useful biosensors of exposure.

The glucocorticoid-induced TNF-related receptor ligand (GITRL) was previously shown to be constitutively expressed at low levels in human eye, including retinal pigment epithelial (RPE) cells. By expressing enhanced yellow fluorescent protein-tagged human GITRL in human RPE cells, we investigated the significance of expression of GITRL on human ocular tissue. Confocal immunofluorescence microscopy and flow cytometry confirmed the surface expression of GITRL on RPE cells. However, a soluble form of GITRL was also detected. Remarkably, expression of GITRL on the RPE cells abrogated RPE-mediated immunosuppression of CD3(+) T cells, implicated as a possible mechanism for ocular immune privilege. This abrogation of immunosuppression by GITRL-RPE was dependent on GITR-GITRL interaction and could not be mimicked by anti-CD28 antibody. Analysis of cytokine profiles revealed high level of TGF-beta during the immunosuppression by RPE cells while expression of GITRL abrogated the RPE cell-induced TGF-beta secretion. Expression of GITRL also stimulates secretion of an array of proinflammatory cytokines/chemokines from T cells. GITR-GITRL interaction provides a unique proinflammatory costimulation that may signal through a different pathway than that of CD28-B7 costimulation. This study implicated that GITRL could be a potential candidate for regulation of the ocular immune privilege and the balance between immune privilege and inflammation.

In recent years, research on human umbilical cord mesenchymal stem cells (hUCMSCs) derived from human umbilical cord tissue has accelerated and entered clinical application research. Compared with mesenchymal stem cells (MSCs) from other sources, hUCMSCs can be extracted from different parts of umbilical cord or from the whole umbilical cord. It has the characteristics of less ethical controversy, high differentiation potential, strong proliferation ability, efficient expansion in vitro, avoiding immune rejection and immune privilege, and avoids the limitations of lack of embryonic stem cells, heterogeneity, ethical and moral constraints. hUCMSCs avoid the need for embryonic stem cell sources, heterogeneity, and ethical and moral constraints. Bone defects are very common in clinical practice, but completely effective bone tissue regeneration treatment is challenging. Currently, autologous bone transplantation and allogeneic bone transplantation are main treatment approaches in clinical work, but each has different shortcomings, such as limited sources, invasiveness, immune rejection and insufficient osteogenic ability. Therefore, to solve the bottleneck of bone tissue regeneration and repair, a great amount of research has been carried out to explore the clinical advantages of hUCMSCs as seed cells to promote osteogenesis.However, the regulation of osteogenic differentiation of hUCMSCs is an extremely complex process. Although a large number of studies have demonstrated that the role of hUCMSCs in enhancing local bone regeneration and repair through osteogenic differentiation and transplantation into the body involves multiple signaling pathways, there is no relevant article that summarize the findings. This article discusses the osteogenesis-related regulatory mechanisms of hUCMSCs, summarizes the currently known related mechanisms, and speculates on the possible signals.

An improved understanding of the interactions at the nanoscale level between the bioceramics in medical implants and the hard or soft tissues in the human body could contribute significantly to the design of new-generation prostheses and postoperative patient management strategies.Overall, the benefits of advanced ceramic materials in biomedical applications have been universally accepted, specifically in terms of their strength, biocompatibility, hydrophilicity, and wear resistance in articulating joints.The continuous development of new-generation implants utilizing nanocoatings with novel nanosensors and devices is leading to better compatibility with human tissue and improved well-being and longevity for patients. This article gives a short overview of bioceramics and reexamines key issues of concern for processing and applying nanoceramics as biomaterials.

A low-profile dual-band millimeter wave patch antenna for high-speed wearable and biomedical applications

Objective: This paper discusses the current status of the treatment and rehabilitation of sports muscle tendon injuries and the application of biomaterials in the repair of sports muscle tendon injuries. Methods: The Chinese Journal Full-text Database (CNKI: 1990/2009) was searched by computer. According to the inclusion and exclusion criteria, the literature was screened, the data was collected and the quality was evaluated, and a total of 28 articles were included. It summarises from the aspects of the mechanism of muscle tendon injury caused by exercise, the treatment and rehabilitation methods of biological materials to repair muscle tendon injury and injury. Results: The research and development of treatment and recovery methods for muscle and tendon injury have always been important issues to be solved urgently. The biomaterials used to repair sports tendon injuries are compatible with human tissues, easily absorbed by tissues, not easily infected, non-adhesive and fractured, and non-repellent, which shows its advantages. Traditional Chinese medicine treatment, sports treatment and medicine are the main rehabilitation methods for functional recovery after tendon injury. Conclusion: In the repair of sports muscle injuries, biomaterials develop rapidly. With the development of research, various treatment and rehabilitation methods for repairing sports muscle tendon injuries will continue to improve.

LuPO4:Nd3+ nanophosphors for dual-mode deep tissue NIR-II luminescence/CT imaging

Light scattering is a primary obstacle to optical imaging in a variety of different environments and across many size and time scales. Scattering complicates imaging on large scales when imaging through the atmosphere when imaging from airborne or space borne platforms, through marine fog, or through fog and dust in vehicle navigation, for example in self driving cars. On smaller scales, scattering is the major obstacle when imaging through human tissue in biomedical applications. Despite the large variety of participating materials and size scales, light transport in all these environments is usually described with very similar scattering models that are defined by the same small set of parameters, including scattering and absorption length and phase function. We attempt a study of scattering and methods of imaging through scattering across different scales and media, particularly with respect to the use of time of flight information. We can show that using time of flight, in addition to spatial information, provides distinct advantages in scattering environments. By performing a comparative study of scattering across scales and media, we are able to suggest scale models for scattering environments to aid lab research. We also can transfer knowledge and methodology between different fields.

Silk fibroin demonstrates great biocompatibility and is suitable for many biomedical applications, including tissue engineering and regenerative medicine. Current research focuses on manipulating the physico-chemical properties of fibroin, and examining the effect of this manipulation on firobin's biocompatibility. Regenerated silk fibroin was modified by in vitro enzymatic phosphorylation and cast into films. Films were produced by blending, at several ratios, the phosphorylated and un-phosphorylated fibroin solutions. Fourier transform infra-red spectroscopy was used to determine the specific P-OH vibration peak, confirming the phosphorylation of the regenerated silk fibroin solution. Differential scanning calorimetry showed that phosphorylation altered the intra- and inter-molecular interactions. Further experiments demonstrated that phosphorylation can be used to tailor the hydrophylicity/hydrophobicity ratio as well as the crystalinity of silk fibroin films. Release profiling of a model drug was highly dependent on silk modification level. Cytotoxicity assays showed that exposure to lixiviates of phosphorylated films only slightly affected cellular metabolism and proliferation, although direct contact resulted in a strong direct correlation between phosphorylation level and cell proliferation. This new method for tuning silk biomaterials to obtain specific structural and biochemical features can be adapted for a wide range of applications. Phosphorylation of silk fibroins may be applied to improve the cytocompatibility of any silk-based device that is considered to be in contact with live animals or human tissues.

Valves are largely useful for treatment assistance devices, e.g., supporting fluid circulation movement in the human body. However, the valves presently used in biomedical applications still use materials that are rigid, non-compliant, and hard to integrate with human tissues. Here, we propose biologically-inspired, stimuli-responsive valves and evaluate N-Isopropylacrylamide hydrogels-based valve (NPHV) and PAAm-alginate hydrogels-based valve (PAHV) performances with different chemical syntheses for optimizing better valve action. Once heated at 40 C, the NPHV outperforms the PAHV in annular actuation (NPHV: 1.93 mm displacement in 4 min; PAHV: 0.8 mm displacement in 30 min). In contrast, the PAHV exhibits a flow rate change of up to 20%, and a payload of 100% when the object is at 100 C. The PAHV demonstrated a completely soft, stretchable circular gripper with a high load-to-weight ratio for diversified applications. These valves are fabricated with a simple one-pot method that, once further optimized, can offer transdisciplinary applications.

Implantable antennas have recently been receiving substantial attention for medical diagnosis and treatment. In this paper, a coplanar waveguide-fed monopole antenna for industrial, scientific, and medical (ISM) band biomedical applications is proposed. The antenna has a simple structure is placed on human tissues such as muscle, fat, and skin. The designed antenna is made compatible for implantation by embedding it in an FR4 substrate. The proposed antenna is simulated using the method of moment's software IE3D by assuming the predetermined dielectric constant for the human muscle tissue, fat, and skin. The antenna operates in the frequency of ISM bands, 2.4–2.48 GHz. Simulated and measured gains attain −7.7 and −8 dBi in the frequency of 2.45 GHz. The radiation pattern, return loss, current distribution, and gain of these antennas were examined and characterized.

Implantable antennas have recently been receiving substantial attention for medical diagnosis and treatment. In this article, a coplanar waveguide‐fed monopole antenna for industrial, scientific, and medical (ISM) band biomedical applications is proposed. The antenna has a simple structure that is placed on human tissues like muscle, fat, and skin. The designed antenna is made compatible for implantation by embedding it in a FR4 substrate. The proposed antenna is simulated using the method of moment's software IE3D by assuming the predetermined dielectric constant for the human muscle tissue, fat, and skin. The antenna operates in the frequency of ISM bands, 2.4 −2.48 GHz. Simulated and measured gains attain −7.7 and −8 dBi in the frequency of 2.45 GHz. The radiation pattern, return loss, current distribution, and gain of these antennas were examined and characterized. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1060–1065, 2014

9 - Graphene oxide-based nanocomposites and biomedical applications

Application of near-infrared light responsive biomaterials for improving the wound healing process: A review

The liver is the most important metabolic organ in the body. While mouse models and cell lines have further deepened our understanding of liver biology and related diseases, they are flawed in replicating key aspects of human liver tissue, particularly its complex structure and metabolic functions. The organoid model represents a major breakthrough in cell biology that revolutionized biomedical research. Organoids are in vitro three-dimensional (3D) physiological structures that recapitulate the morphological and functional characteristics of tissues in vivo, and have significant advantages over traditional cell culture methods. In this review, we discuss the generation strategies and current advances in the field focusing on their application in regenerative medicine, drug discovery and modeling diseases.