Early Stages Of Implantation Research Articles

Bi-directional controlled release of ibuprofen and Mg2 + from magnesium alloys coated by multifunctional composite

Two major problems for magnesium alloy implant are the high degradation rate and easy infection associated with implantation. Herein, a surface drug delivery system (Mg/Epoxy resin-ZnO/PCL-Ibuprofen) which can realize bi-directional controlled release of ibuprofen and Mg2+ was designed via a dip coating process followed by spraying. The in vitro test demonstrated that the ibuprofen in drug-eluting compound material showed sustained release profiles for 22days, which can effectively solve the local cellular rejection and inflammation during the early stage of implantation. Besides, the drug carrier also exhibited improved corrosion resistance duel to the high combining strength between Epoxy resin-ZnO coating and magnesium alloy, so Mg2+ can release slowly at first and then speeded up later. This approach may be suitable for coating other implant materials such as stainless steel, titanium alloy etc.

Degradation pattern of porous CaCO3 and hydroxyapatite microspheres in vitro and in vivo for potential application in bone tissue engineering

Despite superior clinical handling, excellent biocompatibility, biodegradation property of calcium phosphate needs to be improved to coincide with the rate of new bone formation. In this study, spherical CaCO3 are fabricated in the presence of the silk sericin and then transformed into porous hydroxyapatite (HAP) microspheres via hydrothermal method. The degradation behavior of obtained CaCO3, HAP and their mixture is first investigated in vitro. The result demonstrates that the weight loss of HAP microspheres are almost 24.3% after immersing in pH 7.40 Tris-HCl buffer solution for 12 weeks, which is far slower than that of spherical CaCO3 (97.5%). The degradation speed of the mixtures depends on the proportion of CaCO3 and HAP. The mixture with higher content of CaCO3 possesses a quicker degradation speed. The obtained CaCO3 and HAP microspheres are injected into subcutaneous tissue of ICR mice with the assistance of sodium alginate. The result in vivo also shows an obvious difference of degradation speed between the obtained CaCO3 and HAP microspheres, implying it is feasible to modulate the degradation property of the mixture through changing the proportion of CaCO3 and HAP The good cytocompatibility of the two kinds of microspheres is proved and a mild inflammation response is observed only at early stage of implantation. The job offers a simple method to modify the degradation properties of biomaterial for potential use in bone tissue engineering.

The fluoride coated AZ31B magnesium alloy improves corrosion resistance and stimulates bone formation in rabbit model

This study aimed to evaluate the effect of fluorine coated Mg alloy and clarify its mechanism in bone formation. We implanted the fluorine coated AZ31B Mg alloy screw (group F) in rabbit mandibular and femur in vivo. Untreated AZ31B Mg alloy screw (group A) and titanium screw (group T) were used as control. Then, scanning electron microscopy, the spectral energy distribution analysis, hard and decalcified bone tissues staining were performed. Immunohistochemistry was employed to examine the protein expressions of bone morphogenetic protein 2 (BMP-2) and collagen type I in the vicinity of the implant. Compared with the group A, the degradation of the alloy was reduced, the rates of Mg corrosion and Mg ion release were slowed down, and the depositions of calcium and phosphate increased in the group F in the early stage of implantation. Histological results showed that fluorine coated Mg alloy had well osteogenic activity and biocompatibility. Moreover, fluoride coating obviously up-regulated the expressions of collagen type I and BMP-2. This study confirmed that the fluorine coating might improve the corrosion resistance of AZ31B Mg alloy and promote bone formation by up-regulated the expressions of collagen type I and BMP-2.

Enhanced in vitro angiogenic behaviour of human umbilical vein endothelial cells on thermally oxidized TiO2 nanofibrous surfaces.

One of the major challenges in bone grafting is the lack of sufficient bone vascularization. A rapid and stable bone vascularization at an early stage of implantation is essential for optimal functioning of the bone graft. To address this, the ability of in situ TiO2 nanofibrous surfaces fabricated via thermal oxidation method to enhance the angiogenic potential of human umbilical vein endothelial cells (HUVECs) was investigated. The cellular responses of HUVECs on TiO2 nanofibrous surfaces were studied through cell adhesion, cell proliferation, capillary-like tube formation, growth factors secretion (VEGF and BFGF), and angiogenic-endogenic-associated gene (VEGF, VEGFR2, BFGF, PGF, HGF, Ang-1, VWF, PECAM-1 and ENOS) expression analysis after 2 weeks of cell seeding. Our results show that TiO2 nanofibrous surfaces significantly enhanced adhesion, proliferation, formation of capillary-like tube networks and growth factors secretion of HUVECs, as well as leading to higher expression level of all angiogenic-endogenic-associated genes, in comparison to unmodified control surfaces. These beneficial effects suggest the potential use of such surface nanostructures to be utilized as an advantageous interface for bone grafts as they can promote angiogenesis, which improves bone vascularization.

Bioactive compounds immobilized on Ti and TiNbHf: AFM-based investigations of biofunctionalization efficiency and cell adhesion

Implant materials require optimal biointegration, including strong and stable cell-material interactions from the early stages of implantation. Ti-based alloys with low elastic modulus are attracting a lot of interest for avoiding stress shielding, but their osseointegration potential is still very low. In this study, we report on how cell adhesion is influenced by linear RGD, cyclic RGD, and recombinant fibronectin fragment III8–10 coated on titanium versus a novel low-modulus TiNbHf alloy. The bioactive molecules were either physisorbed or covalently coupled to the substrates and their conformation on the surfaces was investigated with atomic force microscopy (AFM). The influence of the different bioactive coatings on the adhesion of rat mesenchymal stem cells was evaluated using cell culture assays and quantitatively analyzed at the single cell level by AFM-based single-cell force spectroscopy. Our results show that bioactive moieties, particularly fibronectin fragment III8–10, improve cell adhesion on titanium and TiNbHf and that the covalent tethering of such molecules provides the most promising strategy to biofunctionalize these materials. Therefore, the use of recombinant protein fragments is of high importance for improving the osseointegration potential of implant materials.

A novel nano-copper-bearing stainless steel with reduced Cu(2+) release only inducing transient foreign body reaction via affecting the activity of NF-κB and Caspase 3.

Foreign body reaction induced by biomaterials is a serious problem in clinical applications. Although 317L-Cu stainless steel (317L-Cu SS) is a new type of implant material with antibacterial ability and osteogenic property, the foreign body reaction level still needs to be assessed due to its Cu2+ releasing property. For this purpose, two macrophage cell lines were selected to detect cellular proliferation, apoptosis, mobility, and the secretions of inflammatory cytokines with the influence of 317L-Cu SS. Our results indicated that 317L-Cu SS had no obvious effect on the proliferation and apoptosis of macrophages; however, it significantly increased cellular migration and TNF-α secretion. Then, C57 mice were used to assess foreign body reaction induced by 317L-Cu SS. We observed significantly enhanced recruitment of inflammatory cells (primarily macrophages) with increased TNF-α secretion and apoptosis level in tissues around the materials in the early stage of implantation. With tissue healing, both inflammation and apoptosis significantly decreased. Further, we discovered that NF-κB pathway and Caspase 3 played important roles in 317L-Cu SS induced inflammation and apoptosis. We concluded that 317L-Cu SS could briefly promote the inflammation and apoptosis of surrounding tissues by regulating the activity of NF-κB pathway and Caspase 3. All these discoveries demonstrated that 317L-Cu SS has a great potential for clinical application.

Investigation of MgO effect on bioactivity of coatings produced by MAO

In this study, a Ti6Al4V alloy surface commonly used in the human body for load-bearing prostheses was modified by micro arc oxidation (MAO) to produce magnesium (Mg)-integrated titanium oxide with varying Mg contents, the presence of which is known to promote bone formation and proliferation in the physiological environment. The in vitro biological responses of these coatings were studied in simulated body fluid (SBF) at 37°C for 6weeks. The structural changes of the coatings, changes in pH and changes in the concentrations of Ca, Mg and P ions in SBF, as determined by inductively coupled plasma (ICP), were monitored at regular intervals. The Tafel polarization technique was used to analyse the solubility properties of the coatings to explain the relation between the Mg concentration of the coatings and the coatings' bioactivity properties. It can be concluded that the presence of Mg in oxide films formed by MAO accelerates dissolution–precipitation reactions and enhances the bioactivity of the films during the early stages of implantation.

Establishment of a novel human embryonic stem cell-derived trophoblastic spheroid implantation model.

Can human embryonic stem cell-derived trophoblastic spheroids be used to study the early stages of implantation? We generated a novel human embryonic stem cell-derived trophoblastic spheroid model mimicking human blastocysts in the early stages of implantation. Both human embryos and choriocarcinoma cell line derived spheroids can attach onto endometrial cells and are used as models to study the early stages of implantation. However, human embryos are limited and the use of cancer cell lines for spheroid generation remains sub-optimal for research. Experimental induced differentiation of human embryonic stem cells into trophoblast and characterization of the trophoblast. Trophoblastic spheroids (BAP-EB) were generated by inducing differentiation of a human embryonic stem cell line, VAL3 cells with bone morphogenic factor-4, A83-01 (a TGF-β inhibitor), and PD173074 (a FGF receptor-3 inhibitor) after embryoid body formation. The expressions of trophoblastic markers and hCG levels were studied by real-time PCR and immunohistochemistry. BAP-EB attachment and invasion assays were performed on different cell lines and primary endometrial cells. After 48 h of induced differentiation, the BAP-EB resembled early implanting human embryos in terms of size and morphology. The spheroids derived from embryonic stem cells (VAL3), but not from several other cell lines studied, possessed a blastocoel-like cavity. BAP-EB expressed several markers of trophectoderm of human blastocysts on Day 2 of induced differentiation. In the subsequent days of differentiation, the cells of the spheroids differentiated into trophoblast-like cells expressing trophoblastic markers, though at levels lower than that in the primary trophoblasts or in a choriocarcinoma cell line. On Day 3 of induced differentiation, BAP-EB selectively attached onto endometrial epithelial cells, but not other non-endometrial cell lines or an endometrial cell line that had lost its epithelial character. The attachment rates of BAP-EB was significantly higher on primary endometrial epithelial cells (EEC) taken from 7 days after hCG induction of ovulation (hCG+7 day) when compared with that from hCG+2 day. The spheroids also invaded through Ishikawa cells and the primary endometrial stromal cells in the co-culture. The attachment rates of BAP-EB were compared between EEC obtained from Day 2 and Day 7 of the gonadotrophin stimulated cycle, but not the natural cycles. BAP-EB have the potential to be used as a test for predicting endometrial receptivity in IVF cycles and provide a novel approach to study early human implantation, trophoblastic cell differentiation and trophoblastic invasion into human endometrial cells.

Early maternal serum ß-human chorionic gonadotropin (ß-hCG) levels and sex-related growth difference of IVF embryos.

Maternal serum ß-human chorionic gonadotropin (ß-hCG) represents the trophoblastic cell mass and is an indirect measurement of embryo development at early implantation stage. Studies in animals and human embryos detected sex-related growth differences (SRGD) in favour of male embryos during the pre-implantation period. The purpose of our study was to correlate SRGD and maternal serum ß-hCG at 16 days after embryo transfer. We retrospectively analysed all (fresh and frozen) non-donor, single embryo transfers (SET), elective and not elective, that were performed between December 2008 and December 2013. We included ß-hCG values from day 16 after oocyte collection of pregnancies resulting in live birth. Neonatal gender was retrieved from patient files. Male and female embryos were further grouped to cleavage and blastocyst stage transfers. Regression analysis for confounding variables included maternal age, maternal body mass index (BMI), use of micromanipulation (ICSI), embryo quality (grade), assisted hatching, day of transfer and fresh or frozen embryo transfer. Seven hundred eighty-six non-donor SETs resulted in live birth. After including only day 16 serum ß-hCG results, 525 SETs were analysed. Neonatal gender was available for 522 cases. Mean maternal serum ß-hCG levels were similar, 347 ± 191 IU/L in the male newborn group and 371 ± 200 IU/L in the female group. The difference between ß-hCG levels remained insignificant after adjusting for confounding variables. Early maternal ß-hCG levels after embryo transfers did not represent SRGD in our study.

Pelota mediates gonocyte maturation and maintenance of spermatogonial stem cells in mouse testes.

Pelota (Pelo) is an evolutionarily conserved gene, and its deficiency in Drosophila affects both male and female fertility. In mice, genetic ablation of Pelo leads to embryonic lethality at the early implantation stage as a result of the impaired development of extra-embryonic endoderm (ExEn). To define the consequences of Pelo deletion on male germ cells, we temporally induced deletion of the gene at both embryonic and postnatal stages. Deletion of Pelo in adult mice resulted in a complete loss of whole-germ cell lineages after 45 days of deletion. The absence of newly emerging spermatogenic cycles in mutants confirmed that spermatogonial stem cells (SSCs) were unable to maintain spermatogenesis in the absence of PELO protein. However, germ cells beyond the undifferentiated SSC stage were capable of completing spermatogenesis and producing spermatozoa, even in the absence of PELO. Following the deletion of Pelo during embryonic development, we found that although PELO is dispensable for maintaining gonocytes, it is necessary for the transition of gonocytes to SSCs. Immunohistological and protein analyses revealed the attenuation of FOXO1 transcriptional activity, which induces the expression of many SSC self-renewal genes. The decreased transcriptional activity of FOXO1 in mutant testes was due to enhanced activity of the PI3K/AKT signaling pathway, which led to phosphorylation and cytoplasmic sequestration of FOXO1. These results suggest that PELO negatively regulates the PI3K/AKT pathway and that the enhanced activity of PI3K/AKT and subsequent FOXO1 inhibition are responsible for the impaired development of SSCs in mutant testes.

Multilayered implantation using acellular dermal matrix into nude mice.

Soft tissue augmentation using acellular dermal matrix has gained popularity to overcome the shortcomings of autogenous and alloplastic materials. Sometimes it needs multilayered stacking to obtain enough volume. In this study, we investigated the efficacy of multilayered implantation using acellular dermal matrix (MatriDerm(®)) for soft tissue augmentation. MatriDerm was implanted subdermally on each side of the dorsum of nude mice (n=20), stacked two layers thick in the control group and three layers thick in the experimental group. Alterations of thickness, degree of angiogenesis, and collagen and elastin fiber syntheses were observed over 40days. Three-layered implantation with MatriDerm maintained its volume similarly as in two-layered implantation, although the thickness decreased after 30days in both groups. At the early stage of implantation, angiogenesis and collagen and elastin fiber syntheses occurred fluently on the central portion, which is the farthest away from the surface in contact with the host tissue. Collagen and elastin fibers became more concentrated over time, and the original structure of MatriDerm could not be maintained due to being replaced with newly formed collagen and elastin fibers 40days after implantation. Multilayered implantation with MatriDerm is considered appropriate for tissue ingrowth and can be used as a substitute for soft tissue augmentation.

Experience of usage of forming rings and protective caps made of PTFE on the single-component implants

Relevance. The main reason that limits the usage of single-component implants, as compared with collapsible (two-component) implants is the high risk of infectious and inflammatory complications in the postoperative period and problems in prosthetics in the esthetically important areas. Therefore, the usage of elements that contribute to healing of the mucous membrane in the early stages of implantation is particularly up-to-date.Work objective is to determine the clinical effectiveness of usage of forming rings and protective caps made of PTFE on the single-component implants in the prevention of peri-implant pathology on a one-step surgical implantation.Materials and methods of the investigation. For this work we used the treatment results of 24 patients with various dentition defects. According to the single-component implant procedure 52 single-component implants were mounted. The head of monolithic implants (38 p.) were isolated by rings or caps made of PTFE. For comparison, 14 implants remained bare for 2-6 weeks before the temporary prosthesis. Postoperatively, subjective feelings were noted in patients, the presence or absence of pain complaints during the examination and palpation, the nature and extent of edema, the phenomena of inflammation around the implant neck were checked. At the stage of sutures removal the degree of soft plaque deposits on the healing elements and titanium implant heads was assessed. Results of the investigation and their discussion. No effects of mucosal hyperemia around the supporting elements made of PTFE were revealed, there was no soft and hard plaque on the rings and caps in most patients of the main group. In patients of the control group, on the contrary, the appearance of the biofilm that covered the head and the implant shoulder on all abutments, which were not protected by a ring or cap, was noted. The healing period of mucous membrane in patients of the control group was longer, the quality of formation of gingival cuff was not optimal.Conclusions1. Usage of forming rings and protective caps made of PTFE on the single-component implants contributes to the qualitative formation of "gingival cuff" around the neck of the implant, which has a positive effect on the aesthetics of the prosthetic work.2. Due to special properties of PTFE there is no soft plaque deposition on healing elements, and thus the risk of development of inflammatory complications around the implant decreases.3. Due to the low thermal conductivity of PTFE protective caps prevent the bone wound from thermal injury in the early stages of healing.4. PTFE caps protect the tongue from the implant head injury before the period of prosthetics.5. Thanks to shortening of the mucous membrane healing around PTFE elements, the quality of functional and aesthetic rehabilitation of patients during one-step implantation improves.

Hernia-repair prosthetic devices functionalised with chitosan and ciprofloxacin coating: controlled release and antibacterial activity.

Polypropylene nets are widely used as hernioplasty prostheses. The reproduction of bacteria within the net fibers intersections can occur after the application of the prosthesis causing infections. For this reason, bacteria have to be removed in the very early stage of surgical implantation. Activation of the prosthesis surface was done by an innovative oxidizing plasma treatment (APP-DBD) working under atmospheric conditions in order to favor the deposition of an antibacterial coating of chitosan (biocompatible carbohydrate) and ciprofloxacin (broad spectrum antibiotic). Two different coating mixtures were realised and the antibacterial properties of such functionalised nets were investigated, together with their effectiveness. Physico-chemical characterisations of meshes were carried out before and after functionalisation by SEM-EDS and infrared spectroscopy. The release of both chitosan and ciprofloxacin, under controlled experimental conditions, was followed respectively by colorimetric determination (using UV-Visible spectroscopy) and chromatographic analysis (using HPLC). In vitro tests allow verifying antimicrobial activity (inoculation of specimens in a Staphylococcus aureus suspension).

Adsorption and Release Behaviors of Vascular Endothelial Growth Factor on Porous Hydroxyapatite Ceramic Under Competitive Conditions

National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064, ChinaVascular endothelial growth factor plays a positive role in the vascularization of bone grafts afterimplantation. In the present study, we constructed a multi-protein system and investigated itsadsorption and release on porous hydroxyapatite ceramic under competitive conditions, and wealso evaluated its bioactivity by cells proliferation experiments after it released from the ceramic.The results showed that vascular endothelial growth factor always had a high adsorption on poroushydroxyapatite ceramic, whether having the inhibition of other serum proteins or not. When incu-bated in the cell culture medium containing 10% fetal calf serum, the pre-loaded vascular endothelialgrowth factor showed a slow and sustained release from the ceramic. After 7 days of incubation,its accumulative release rate was only about 50%. The high adsorption and slow release of vas-cular endothelial growth factor on porous hydroxyapatite ceramic should be ascribed to the strongelectrostatic attraction between them as well as the abundant nano-sized micropores present onthe ceramic surface. The cell culture experiments con“rmed that the released vascular endothelialgrowth factor from porous hydroxyapatite ceramic could promote the proliferation of human umbilicalvein endothelial cells signi“cantly, indicating that its bioactivity was still maintained after desorb-ing from the ceramic. As thus, it could be inferred that porous hydroxyapatite ceramic may adsorband accumulate the endogenous vascular endothelial growth factor at the early implantation stage,which then releases from the ceramic surface gradually and takes effect on the ingrown vascularendothelial cells, leading to the rapid vascularization of the implant.

Endocrine and metabolic mechanisms of embryo and fetal intrauterine growth retardation in dairy cows

This research was conducted to study hormonal and metabolic statuses and to determine ultrasound criteria for early diagnosis of fetal growth retardation syndrome (FGRS) in dairy cows of Black-motley (n = 41) and Red-motley (n = 56) Holstein breeds. Concentrations of progesterone, testosterone, 17beta-estradiol, dehydroepiandrosterone sulfate, cortisol, and triiodothyronine in blood serum were assessed by immune-enzyme analysis. Concentrations of plasma L-ascorbic acid and nitrogen oxides, serum immune globulin, middle molecular peptides, and bactericidal and lysozyme activity were determined by spectrophotometry. On days 38-40 and 60-65 of gestation, FGRS in cows was associated with hypoprogesteronemia, decrease of adrenal and thyroid gland functions, decreased nitric oxide synthesis, low immune responsiveness, and high endogenous intoxication. In conclusion, body length less than 16 mm on days 38-40 and less than 45 mm on days 60-65 are the criteria for designating underdevelopment of embryos and fetuses in dairy cows. FGRS genesis in dairy cows is determined by the embryo's and fetus's malnutrition at the early implantation and placentation stages, caused by the imbalance of endocrine regulation, nitric oxide systems, and endogenous intoxication.

The accelerated atherogenesis of venous grafts might be attributed to aggravated concentration polarization of low density lipoproteins: A numerical study

We hypothesize that after implantation the much elevated water filtration rate of venous grafts may cause aggravated concentration polarization of low density lipoproteins (LDLs), in turn lead to the accelerated atherogenesis of the grafts. To verify the hypothesis, we numerically simulated the transport of LDLs in various models of arterial bypasses with different grafts (veins or arteries) and geometrical configurations. The results showed that the venous grafts might endure abnormally high lipid infiltration/accumulation within the vessel wall due to severely elevated luminal surface LDL concentration. When compared to the conventional bypass models, the S-type bypass had the lowest luminal surface LDL concentration along its host artery floor, but the highest degree of risk to develop atherosclerotic lesions in its venous graft. Among the three conventional bypass models, the one with 30° anastomosis had the lowest risk to develop atherosclerosis in the venous graft. In conclusion, when compared with the bypass models with arterial grafts, the venous bypass models had rather high levels of LDL concentration polarization (cw) in the vein grafts, especially at the early stages of implantation. This might result in high infiltration/accumulation of LDLs within the walls of the venous grafts, leading to a fast genesis/development of atherosclerosis there.

Human chorionic gonadotropin (hCG) modulation of TIMP1 secretion by human endometrial stromal cells facilitates extravillous trophoblast invasion in vitro

Are secreted extracellular matrix (ECM) remodelling elements, relevant to embryo implantation and placentation, modified by hCG in endometrial stromal cells (ESCs)? hCG decreases tissue inhibitor of metalloproteinase 1 (TIMP-1) secretion in ESCs, thereby facilitating extravillous trophoblast invasion in vitro. Successful embryo implantation and placentation depend on the appropriate invasion of the trophoblast into the maternal endometrial stroma. hCG is one of the earliest embryo-derived secreted signals in the endometrium which abundantly expresses hCG receptors. However, there is little data concerning the effects of hCG on endometrial ECM remodelling with respect to embryo implantation. This study was conducted in an academic research laboratory within a tertiary-care hospital. Samples were collected from 36 women undergoing benign gynaecological surgery during the mid-secretory phase. ESCs were isolated and stimulated with hCG (10 UI/ml) or vehicle. Conditioned media (CM) were analysed to determine changes in the secreted profile of nine matrix metalloproteinases (MMPs) and three tissue-specific inhibitors of MMPs (TIMPs) using an ELISA array. Data were confirmed by gelatine zymography, western blot and ELISA. The HTR8/SVneo cell line served as a model for trophoblast cells. The invasive potential of trophoblast cells was assessed using Transwell invasion assays under CM or co-culture conditions with ECS and the role of regulated molecules was examined by using immunoprecipitation in CM prior to the assessment of invasive potential. MMP-2 levels increased 30%, whereas TIMP-1 levels decreased 20% in CM from ESCs stimulated with hCG (P < 0.05). Gelatine zymography confirmed an increase in MMP-2 activity (P < 0.05). ELISA and western blotting also confirmed the reduction in TIMP-1 upon hCG treatment (P < 0.05). Invasion assays revealed a ∼50% increase in invading HTR8/SVneo cells in chambers with hCG-stimulated ESCs compared with the control (P < 0.05). Immunodepletion of TIMP-1 from control ESC-CM partially resembled the effect of CM from hCG-stimulated ESCs in the trophoblast invasion assays. The assays were performed in vitro and ESCs were not decidualized, therefore they reflected the very early stages of embryo implantation or the advanced stages when decidualization fails. Our data suggest that hCG induces endometrial stromal extracellular remodelling by modulating secreted MMP-2 and TIMP-1. This regulation may be physiologically relevant because it increases the invasive potential of trophoblast-derived cells. At present, few data exist concerning the implications of hCG and endometrial ECM remodelling in embryo implantation. Hence, our results should be confirmed by further in vivo studies. This work was funded by FONDECYT 11100443, PBCT-PSD51 (IDIMI) and FONDAP 15010006. None of the authors have any conflicts of interest to declare.

Improvement of drug elution in thin mineralized collagen coatings with PLGA‐PEG‐PLGA micelles

A mineralized collagen (MC) coating on metallic implants has shown great potential as orthopedic material due to high biological responses. However, their drug delivery capacity remains unsatisfactory since a serious burst release may occur and long-term release is hard to be achieved. Aiming to improve the drug-eluting capability, we incorporated drug-loaded PLGA-PEG-PLGA (PPP) micelles into the thin coating. The in vitro release profiles showed that the burst release in the initial 8 h of the modified coating decreased from 81% to 58% compared to MC coating alone; meanwhile, the release duration was prolonged from 3 days to 1 week. Additionally, the release kinetics of vancomycin hydrochloride (VH, the model drug) could be adjusted by changing the size and concentration of PPP micelles. Interestingly, less initial release of VH caused by micelle immobilization did not affect the antibacterial activity in the early stage of implantation according to the antimicrobial test. The cytocompatibility assay demonstrated that the VH-loaded PPP micelles did not have negative effect on the bioactivity of coating which greatly enhanced cell activity compared to bare Ti substrates. Thus, the MC coatings with PPP micelles could be an effective implant route for bone repair.

Histochemical Study of early Embryo Implantation in Mice

Implantation involves a complex process between the embryo and uterus and is crucial to further embryonic development. In this histochemical study, we investigated the early stage of embryo implantation and artificial decidualization in mice by the detection of total proteins and glycosaminoglycans using toluidine blue at pH 4.0 (TB) and Xylidine Ponceau at pH 2.5 (XP). TB staining showed mild metachromatic basophilia, which was more visible in the endometrial stroma around the implantation site in day 5 of pregnancy, and the level of glycosaminoglycans was more intense near the site of implantation on day 6, 8. Histochemical staining with XP was observed more intense in the stroma close to the site of implantation, especially in day 8 of pregnancy. At sites distant from the blastocyst were observed more discrete by staining with either TB or XP. Compared with TB, XP were more evident in the stroma around the uterine lumen under artificial decidualization. This study demonstrated changes in glycosaminoglycans and proteins by the detection of anionic and cationic radicals in the endometrial stroma adjacent to the site of embryo implantation during peri-implantation, post-implantation and artificial decidualization.

The interplay between nanostructured carbon-grafted chitosan scaffolds and protein adsorption on the cellular response of osteoblasts: Structure–function property relationship

The rapid adsorption of proteins occurs during the early stages of biomedical device implantation into physiological systems. In this regard, the adsorption of proteins is a strong function of the nature of a biomedical device, which ultimately governs the biological functions. The objective of this study was to elucidate the interplay between nanostructured carbon-modified (graphene oxide and single-walled carbon nanohorn) chitosan scaffolds and consequent protein adsorption and biological function (osteoblast function). We compare and contrast the footprint of protein adsorption on unmodified chitosan and nanostructured carbon-modified chitosan. A comparative analysis of cell–substrate interactions using an osteoblast cell line (MC3T3-E1) implied that biological functions were significantly enhanced in the presence of nanostructured carbon, compared with unmodified chitosan. The difference in their respective behaviors is related to the degree and topography of protein adsorption on the scaffolds. Furthermore, there was a synergistic effect of nanostructured carbon and protein adsorption in terms of favorably modulating biological functions, including cell attachment, proliferation and viability, with the effect being greater on nanostructured carbon-modified scaffolds. The study also underscores that protein adsorption is favored in nanostructured carbon-modified scaffolds such that bioactivity and biological function are promoted.