Multimodal training with dual-task enhances immediate and retained effects on dual-task effects of gait speed not by cognitive-motor trade-offs in stroke survivors: a randomized controlled trial.

PURPOSE: Individuals who have experienced stroke may benefit from dual-task related training to improve gait speed performance. Whether noted improvements reflect true effects on gait or cognitive-motor trade-offs still remains unclear. Therefore, this study aimed to investigate the effects of dual-task training on dual-task effects of both walking and cognitive domains in stroke survivors. MATERIALS AND METHODS: Forty-four individuals with stroke were randomized to dual-task or single-task training groups. Both groups exercised three 60-minute sessions per week for 4 weeks. The primary outcomes were dual-task effects on gait speed and cognitive score. Outcomes were assessed before and after the intervention and 1-month follow-up. RESULTS: While both groups exhibited improvement in absolute gait speed under dual-task conditions, the dual-task training group demonstrated superior results by providing an additional gain on dual-task effects of gait speed. Compared to single-task training, dual-task training exhibited a significant improvement in dual-task effects of gait speed at post-treatment and follow-up. Regarding the dual-task effects on cognitive scores, no significant differences within and between groups after training were observed. CONCLUSION: Dual-task training enhances immediate and retained effects on the dual-task effects of gait speed in individuals with stroke, not by cognitive-motor trade-offs. TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. CLINICALTRIALS.GOV IDENTIFIER: NCT02686515.

Dual-task interference during walking has important consequences for stroke survivors to walk safely.Multimodal training with dual-task enhances immediate and retained effects on the dual-task effects of gait speed in individuals with stroke, not by cognitive-motor trade-offs.Clinicians are encouraged to incorporate multimodal training with dual-task into the exercise routines to enhance walking under dual-task conditions in stroke survivors.

Achieving Bright Organic Light-Emitting Field-Effect Transistors with Sustained Efficiency through Hybrid Contact Design.

Organic light-emitting field-effect transistors (OLEFETs) with bilayer structures have been widely studied due to their potential to integrate high-mobility organic transistors and efficient organic light-emitting diodes. However, these devices face a major challenge of imbalance charge transport, leading to a severe efficiency roll-off at high brightness. Here, we propose a solution to this challenge by introducing a transparent organic/inorganic hybrid contact with specially designed electronic structures. Our design aims to steadily accumulate the electrons injected into the emissive polymer, allowing the light-emitting interface to effectively capture more holes even when the hole current increases. Our numerical simulations show that the capture efficiency of these steady electrons will dominate charge recombination and lead to a sustained external quantum efficiency of 0.23% over 3 orders of magnitude of brightness (4 to 7700 cd/m2) and current density (1.2 to 2700 mA/cm2) from -4 to -100 V. The same enhancement is retained even after increasing the external quantum efficiency (EQE) to 0.51%. The high and tunable brightness with stable efficiency offered by hybrid-contact OLEFETs makes them ideal light-emitting devices for various applications. These devices have the potential to revolutionize the field of organic electronics by overcoming the fundamental challenge of imbalance charge transport.

Development of a Predictive Model for Optimization of Embryo Transfer Timing Using Blood-Based microRNA Expression Profile.

MicroRNAs (miRNAs) can regulate the expression of genes involved in the establishment of the window of implantation (WOI) in the endometrium. Recent studies indicated that cell-free miRNAs in uterine fluid and blood samples could act as alternative and non-invasive sample types for endometrial receptivity analysis. In this study, we attempt to systematically evaluate whether the expression levels of cell-free microRNAs in blood samples could be used as non-invasive biomarkers for assessing endometrial receptivity status. We profiled the miRNA expression levels of 111 blood samples using next-generation sequencing to establish a predictive model for the assessment of endometrial receptivity status. This model was validated with an independent dataset (n = 73). The overall accuracy is 95.9%. Specifically, we achieved accuracies of 95.9%, 95.9%, and 100.0% for the pre-receptive group, the receptive group, and the post-respective group, respectively. Additionally, we identified a set of differentially expressed miRNAs between different endometrial receptivity statuses using the following criteria: p-value < 0.05 and fold change greater than 1.5 or less than -1.5. In conclusion, the expression levels of cell-free miRNAs in blood samples can be utilized in a non-invasive manner to distinguish different endometrial receptivity statuses.

An Innovative Customized Biomimetic Hydrogel for Drug Screening Application Potential: Biocompatibility and Cell Invasion Ability.

The ability of Pluronic F127 (PF127) conjugated with tetrapeptide Gly-Arg-Gly-Asp (GRGD) as a sequence of Arg-Gly-Asp (RGD) peptide to form the investigated potential hydrogel (hereafter referred to as 3DG bioformer (3BE)) to produce spheroid, biocompatibility, and cell invasion ability, was assessed in this study. The fibroblast cell line (NIH 3T3), osteoblast cell line (MG-63), and human breast cancer cell line (MCF-7) were cultured in the 3BE hydrogel and commercial product (Matrigel) for comparison. The morphology of spheroid formation was evaluated via optical microscopy. The cell viability was observed through cell counting Kit-8 assay, and cell invasion was investigated via Boyden chamber assay. Analytical results indicated that 3BE exhibited lower spheroid formation than Matrigel. However, the 3BE appeared biocompatible to NIH 3T3, MG-63, and MCF-7 cells. Moreover, cell invasion ability and cell survival rate after invasion through the 3BE was displayed to be comparable to Matrigel. Thus, these findings demonstrate that the 3BE hydrogel has a great potential as an alternative to a three-dimensional cell culture for drug screening applications.

Factors that Hinder 24-Hour Discharge After Laparoscopic Roux-en-Y Gastric Bypass: a Retrospective Analysis at a Low-Volume Center.

PURPOSE: This study aimed to identify factors that hinder 24-h patient discharge after laparoscopic Roux-en-Y gastric bypass (LRYGB) in a low-volume practice. MATERIAL AND METHODS: Consecutive patients who fulfilled regional criteria and underwent primary LRYGB from 2018 to 2020 were retrospectively analyzed. Patients were discharged on the morning of the first postoperative day (POD1) after meeting the predefined criteria. The assessed outcome measures (POD1 vital signs, laboratory findings, pain scores and nausea/vomiting) and 30-day postoperative complications were compared between the early (stay ≤ 24 h) and delayed (>24 h) groups. RESULTS: For 107 patients who fulfilled the inclusion criteria, 48 (44.9%) were discharged within 24 h. There were no differences in the baseline demographics, except that the early group was more likely to have a previous abdominal operation (35.4% vs. 16.9%). Both groups had similar operation durations (89 min vs. 92 min), but the early group had a markedly shortened length of stay (23 (24-22) h vs. 27 (47-26) h). The POD1 parameters were the same between the groups, except that the delay group had a significantly higher visual analog scale score, with fewer patient scores of 0. Patients who were younger and female were more likely to need additional IV analgesics. No POD1 antiemesis was required throughout the study. There was no increase in the 30-day complications. CONCLUSION: Patient discharge at 24 h post-LRYGB is feasible and safe in a low-volume practice. A more comprehensive pain relief strategy may be required before generalizing this approach.

Effects of ankle continuous passive motion on soleus hypertonia in individuals with cerebral palsy: A case series.

BACKGROUND: Continuous passive motion device (CPM) provides repetitive movement over extended periods of time for those who have low functional ability. The purpose of this research was to evaluate the effects of a four-week program of continuous passive motion of the ankle joint on the changes in soleus hypertonia in individuals with cerebral palsy who suffered from life-long hypertonia. METHODS: A single group, repeated-measures study was conducted. Eight individuals (7 males and 1 female with a mean age of 21.8 ± 8.5 years) with spastic cerebral palsy underwent bilateral ankle CPM for 1 h a day, 5 days a week, for 4 weeks. The outcome measures included the Modified Ashworth Scale (MAS) score, passive range of motion (PROM) of the ankle, the ratio of maximum H reflex to maximum soleus M-response (H/M ratio), and post-activation depression (PAD). All outcomes were measured before and after the intervention. A paired t-test was used to examine treatment effects pre-versus post-intervention. RESULTS: Paired t-tests showed that the CPM program significantly decreased the MAS score (p = 0.006), decreased the maximum H/M ratio (p=0.001), improved PAD (p = 0.003, p = 0.040, and p = 0.032 at 0.2 Hz, 1 Hz, and 2 Hz, respectively), and increased the passive ankle range of motion (p = 0.049). CONCLUSION: Ankle CPM not only reduced soleus hypertonia but also improved the PROM in individuals with cerebral palsy. The results of this study show ankle CPM to be an effective intervention for individuals with cerebral palsy.

Monascin accelerates anoikis in circulating tumor cells and prevents breast cancer metastasis.

Anoikis resistance has been observed in various types of cancers in which anchorage-independent growth is a crucial step for cancer metastasis. Therefore, agents interfering with this specific cancer cell behavior may be integrated into novel antimetastatic strategies. Monascin (MS), a secondary metabolite found in Monascus species, is a known potent chemopreventive compound used for treating metabolic complications; however, the effect of MS on anoikis resistance has not been investigated. In this study, 4T1 breast cells were treated with MS under either suspension or adhesion conditions. The higher cytotoxicity of MS was more potent against suspended cells than against adherent cells. This selective cytotoxicity was due to the induction of anoikis, which was evidenced by changes in cell aggregation, caspase activity, and Annexin V/propidium iodide binding as well as the results of systemic metastasis in an animal model. Furthermore, MS inhibited E-cadherin and ß-catenin expression in the cells; the treated cells formed spherical aggregates, which suggested that anchorage-independent growth was prevented by MS. These results provide new insights into the mechanisms underlying the growth-preventing effect of MS on cancer cells and indicate the potential ability of MS to suppress metastasis.

Fish-Scale Collagen Membrane Seeded with Corneal Endothelial Cells as Alternative Graft for Endothelial Keratoplasty Transplantation.

The human corneal endothelium has limited regeneration capacity. Several methods have been developed in an attempt to repair it. Descemet stripping automated endothelial keratoplasty (DSAEK) is commonly performed on patients with endothelial dysfunction. However, donor demand far exceeds donor supply. Here, we prepared fish-scale collagen membrane (FSCM) and seeded it with CECs in preparation for corneal endothelial transplantation. The fish scales were decellularized, decalcified, and curved. The FSCM was inspected by fluorescence microscopy, SEM, and TGA to validate decellularization, microstructure, and decalcification, respectively. The cytotoxicity of FSCM and the viability of the cells in contact with it were evaluated by LDH and WST-1, respectively. CEC tight junctions and ZO-1 structure were observed by SEM and confocal microscopy. FSCM seeded with CECs were implanted to rabbit anterior chambers to evaluate host tissue reactions to it. FSCM biocompatibility and durability were also assessed. The results showed that FSCM has excellent transparency, adequate water content, and good biocompatibility. The cultivated CECs mounted on the FSCM were similar to normal CECs in vivo. The FSCM plus CECs developed here have high potential efficacy for endothelial keratoplasty transplantation.

DriverDBv3: a multi-omics database for cancer driver gene research.

An integrative multi-omics database is needed urgently, because focusing only on analysis of one-dimensional data falls far short of providing an understanding of cancer. Previously, we presented DriverDB, a cancer driver gene database that applies published bioinformatics algorithms to identify driver genes/mutations. The updated DriverDBv3 database (http://ngs.ym.edu.tw/driverdb) is designed to interpret cancer omics' sophisticated information with concise data visualization. To offer diverse insights into molecular dysregulation/dysfunction events, we incorporated computational tools to define CNV and methylation drivers. Further, four new features, CNV, Methylation, Survival, and miRNA, allow users to explore the relations from two perspectives in the 'Cancer' and 'Gene' sections. The 'Survival' panel offers not only significant survival genes, but gene pairs synergistic effects determine. A fresh function, 'Survival Analysis' in 'Customized-analysis,' allows users to investigate the co-occurring events in user-defined gene(s) by mutation status or by expression in a specific patient group. Moreover, we redesigned the web interface and provided interactive figures to interpret cancer omics' sophisticated information, and also constructed a Summary panel in the 'Cancer' and 'Gene' sections to visualize the features on multi-omics levels concisely. DriverDBv3 seeks to improve the study of integrative cancer omics data by identifying driver genes and contributes to cancer biology.

Netrin-1 Dampens Hypobaric Hypoxia-Induced Lung Injury in Mice.

Background: This study aimed to explore the effects of netrin-1 on hypobaric hypoxia-induced lung injury in mice. Methods: We exposed 6-8-week-old C57BL/6 mice to hypobaric stress at 340 mmHg for 30 minutes followed by 260 mmHg for different periods (6, 12, 18, and 24 hours) to observe the severity of lung injury (O2 concentration, 21%; 54.6 mmHg). The wet/dry weight ratio and protein leakage from the mouse lung were used to determine the suitable exposure time. Netrin-1 was injected into the tail vein of mice before 18-hour decompression. Inflammatory cytokines, lung injury scores, and activity of nuclear factor κB were evaluated. The expression of apoptosis-related proteins was also examined. Results: Protein concentration in the bronchoalveolar lavage fluid was significantly higher in the 18-hour group (p < 0.05). Pulmonary pathology revealed neutrophil infiltration, alveolar septum thickening, and tissue edema. Injury score and macrophage inflammatory protein 2 levels were also increased. Intrinsic apoptosis pathway was activated. Hypoxia decreased the expression of Bcl2 protein, the number of active caspase-3-stained cells, and UNC5HB receptors. Pretreatment with netrin-1 reduced protein leakage, inhibited neutrophil migration, lowered the injury score, attenuated apoptosis, and increased UNC5HB receptor expression. Conclusion: Netrin-1 dampens hypobaric hypoxia-induced lung injury by inhibiting neutrophil migration and attenuating apoptosis.

Infraclavicular brachial plexus block in adults: a comprehensive review based on a unified nomenclature system.

Over the last decade, considerable progress has been made regarding infraclavicular brachial plexus block (ICB) in adults, especially since the introduction of ultrasound guidance. The advancements in ICB have been attributed to the development of various approaches to improve the success rate and reduce complications. This has also necessitated a unified nomenclature system to facilitate comparison among different approaches. This review aimed to propose an anatomical nomenclature system by classifying ICB approaches into proximal and distal ones to aid future research and provide practice advisories according to recent updates. We also comprehensively discuss various aspects of this nomenclature system. Our review suggests that ultrasound-guided ICB should be categorized as an advanced technique that should be performed under supervision and dual guidance. For one-shot block, the conventional distal approach is still preferred but should be modified to follow ergonomic practice, with the arm in the proper position. For continuous ICB, the proximal approach is promising for reducing local anesthetic volume and increasing efficacy. Nevertheless, further studies are warranted in this direction. We provide practice advisories to maximize safety and minimize adverse events, and recommend designing future studies on ICB according to these findings based on the unified nomenclature system.

Targeted Sequencing of Circulating Tumor DNA to Monitor Genetic Variants and Therapeutic Response in Metastatic Colorectal Cancer.

Substantial improvements have been made in the management of metastatic colorectal cancer (mCRC) in the last two decades, but disease monitoring remains underdeveloped. Circulating tumor DNA (ctDNA) is a promising prognostic and predictive biomarker; however, ctDNA as a marker for mCRC patients is not well established, and there is still no consensus about how to utilize it most cost-effectively. In this study, we aim to investigate plasma ctDNA levels as a biomarker for therapeutic response of mCRC patients. We performed next-generation sequencing (NGS) by using a 12-gene panel to identify genetic variants in 136 tumor tissue and ctDNA samples from 32 mCRC patients. Genetic variants were detected in approximately 70% of samples, and there was a high concordance (85%) between tumor tissue and plasma ctDNA. We observed ctDNA changes in 18 follow-up patients, including the emergence of new variants. Changes in ctDNA levels significantly correlated with tumor shrinkage (P = 0.041), and patients with a ctDNA decrease >80% after treatment had a longer progression-free survival compared with patients with a ctDNA decrease of <80% (HR, 0.22; P = 0.015). The objective response rate among patients with a ctDNA decrease of >80% was better than those with a ctDNA decrease <80% (OR, 0.026; P = 0.007). In conclusion, this study demonstrates that monitoring of genetic ctDNA variants can serve as a valuable biomarker for therapeutic efficacy in mCRC patients, and that using a moderate-sized 12-gene NGS panel may be suitable for such clinical monitoring. Mol Cancer Ther; 17(10); 2238-47. ©2018 AACR.

Intestinal FXYD12 and sodium-potassium ATPase: A comparative study on two euryhaline medakas in response to salinity changes.

FXYD proteins are the regulators of sodium-potassium ATPase (Na+/K+-ATPase, NKA). In teleosts, NKA is a primary driving force for the operation of many ion transport systems in the osmoregulatory organs (e.g. intestines). Hence, the purpose of this study was to determine the expression of FXYD proteins and NKA α-subunit in the intestines of two closely related medakas (Oryzias dancena and O. latipes), which came from different salinity habitats and have diverse osmoregulatory capabilities, to illustrate the association between NKA and FXYD proteins of two medaka species in response to salinity changes. The results showed that the fxyd12 mRNA was the most predominant in the intestines of both medakas. The association of FXYD12 and NKA in the intestines of the two medaka species was demonstrated via double immunofluorescent staining and co-immunoprecipitation. Upon salinity challenge, the localization of FXYD12 and NKA was similar in the intestines of the two medaka species. However, the expression profiles of intestinal FXYD12 and NKA (mRNA and protein levels), as well as NKA activity differed between the medakas. These results showed that FXYD12 may play a role in modulating NKA activity in the intestines of the two medakas following salinity changes in the maintenance of internal homeostasis. These findings contributed to knowledge of the expression and potential role of vertebrate FXYD12, the regulators of NKA, upon salinity challenge.

Arctigenin protects against steatosis in WRL68 hepatocytes through activation of phosphoinositide 3-kinase/protein kinase B and AMP-activated protein kinase pathways.

Arctigenin (ATG), a lignin extracted from Arctium lappa (L.), exerts antioxidant and anti-inflammatory effects. We hypothesized that ATG exerts a protective effect on hepatocytes by preventing nonalcoholic fatty liver disease (NAFLD) progression associated with lipid oxidation-associated lipotoxicity and inflammation. We established an in vitro NAFLD cell model by using normal WRL68 hepatocytes to investigate oleic acid (OA) accumulation and the potential bioactive role of ATG. The results revealed that ATG inhibited OA-induced lipid accumulation, lipid peroxidation, and inflammation in WRL68 hepatocytes, as determined using Oil Red O staining, thiobarbituric acid reactive substance assay, and inflammation antibody array assays. Quantitative RT-PCR analysis demonstrated that ATG significantly mitigated the expression of acetylcoenzyme A carboxylase 1 and sterol regulatory element-binding protein-1 and significantly increased the expression of carnitine palmitoyltransferase 1 and peroxisome proliferator-activated receptor alpha. The 40 targets of the Human Inflammation Antibody Array indicated that ATG significantly inhibited the elevation of the U937 lymphocyte chemoattractant, ICAM-1, IL-1ß, IL-6, IL-6sR, IL-7, and IL-8. ATG could activate the phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) and AMP-activated protein kinase (AMPK) pathways and could increase the phosphorylation levels of Akt and AMPK to mediate cell survival, lipid metabolism, oxidation stress, and inflammation. Thus, we demonstrated that ATG could inhibit NAFLD progression associated with lipid oxidation-associated lipotoxicity and inflammation, and we provided insights into the underlying mechanisms and revealed potential targets to enable a thorough understanding of NAFLD progression.

Exploring optimal supplement strategy of medicinal herbs and tea extracts for bioelectricity generation in microbial fuel cells.

This first-attempt study used extracts of appropriate antioxidant abundant Camellia and non-Camellia tea and medicinal herbs as model ESs to stably intensify bioelectricity generation performance in microbial fuel cells (MFCs). As electron shuttles (ESs) could stimulate electron transport phenomena by significant reduction of electron transfer resistance, the efficiency of power generation for energy extraction in microbial fuel cells (MFCs) could be appreciably augmented. Using environmentally friendly natural bioresource as green bioresource of ESs is the most promising to sustainable practicability. As comparison of power-density profiles indicated, supplement of Camellia tea extracts would be the most appropriate, then followed non-Camellia Chrysanthemum tea and medicinal herbs. Antioxidant activities, total phenolic contents and power stimulating activities were all electrochemically associated. In particular, the extract of unfermented Camellia tea (i.e., green tea) was the most promising ESs to augment bioenergy extraction compared to other refreshing medicinal herb extracts.

Effect of EMG-triggered neuromuscular electrical stimulation with bilateral arm training on hemiplegic shoulder pain and arm function after stroke: a randomized controlled trial.

BACKGROUND: Hemiplegic shoulder pain is a frequent complication after stroke, leading to limited use of the affected arm. Neuromuscular electrical stimulation (NMES) and transcutaneous electrical nerve stimulation (TENS) are two widely used interventions to reduce pain, but the comparative efficacy of these two modalities remains uncertain. The purpose of this research was to compare the immediate and retained effects of EMG-triggered NMES and TENS, both in combination with bilateral arm training, on hemiplegic shoulder pain and arm function of stroke patients. METHODS: A single-blind, randomized controlled trial was conducted at two medical centers. Thirty-eight patients (25 males and 13 females, 60.75 ± 10.84 years old, post stroke duration 32.68 ± 53.07 months) who had experienced a stroke more than 3 months ago at the time of recruitment and hemiplegic shoulder pain were randomized to EMG-triggered NMES or TENS. Both groups received electrical stimulation followed by bilateral arm training 3 times a week for 4 weeks. The primary outcome measures included a vertical Numerical Rating Scale supplemented with a Faces Rating Scale, and the short form of the Brief Pain Inventory. The secondary outcome measures were the upper-limb subscale of the Fugl-Meyer Assessment, and pain-free passive shoulder range of motion. All outcomes were measured pretreatment, post-treatment, and at 1-month after post-treatment. Two-way mixed repeated measures ANOVAs were used to examine treatment effects. RESULTS: Compared to TENS with bilateral arm training, the EMG-triggered NMES with bilateral arm training was associated with lower pain intensity during active and passive shoulder movement (P =0.007, P =0.008), lower worst pain intensity (P = 0.003), and greater pain-free passive shoulder abduction (P =0.001) and internal rotation (P =0.004) at follow-up. Both groups improved in pain at rest (P =0.02), pain interference with daily activities, the Fugl-Meyer Assessment, and pain-free passive shoulder flexion and external rotation post-treatment (P < 0.001) and maintained the improvement at follow-up (P < 0.001), except for resting pain (P =0.08). CONCLUSIONS: EMG-triggered NMES with bilateral arm training exhibited greater immediate and retained effects than TENS with bilateral arm training with respect to pain and shoulder impairment for chronic and subacute stroke patients with hemiplegic shoulder pain. TRIAL REGISTRATION: NCT01913509 .

Patient knowledge and pulmonary medication adherence in adult patients with cystic fibrosis.

BACKGROUND AND OBJECTIVES: Patient knowledge of lung function (ie, forced expiratory volume in 1 s [FEV1]% predicted) and the intended benefits of their prescribed pulmonary medications might play an important role in medication adherence, but this relationship has not been examined previously in patients with cystic fibrosis (CF). METHODS: All patients diagnosed with CF and without prior lung transplantation were invited to complete knowledge and self-reported medication adherence questionnaires during routine outpatient visits to the Adult CF Clinic, St Paul's Hospital, Vancouver, Canada from June 2013 to August 2014. RESULTS: A total of 142 out of 167 (85%) consecutive adults attending CF clinic completed patient knowledge and medication adherence survey questionnaires. Sixty-four percent of the patients recalled their last FEV1% predicted value within 5%, and 70% knew the intended benefits of all their prescribed medications. Self-reported adherence rates were highest for inhaled antibiotics (81%), azithromycin (87%), and dornase alpha (76%) and lowest for hypertonic saline (47%). Individuals who knew their FEV1% predicted value within 5% were more likely to self-report adherence to dornase alpha (84% vs 62%, P=0.06) and inhaled antibiotics (88% vs 64%, P=0.06) compared to those who did not, but these associations were not statistically significant. There were no significant associations observed between patient knowledge of intended medication benefits and self-reported medication adherence. CONCLUSION: Contrary to our hypothesis, disease- and treatment-related knowledge was not associated with self-reported medication adherence. This suggests other barriers to medication adherence should be targeted in future studies aiming to improve medication adherence in adults with CF.

The Spatiotemporal Control of Osteoblast Cell Growth, Behavior, and Function Dictated by Nanostructured Stainless Steel Artificial Microenvironments.

The successful application of a nanostructured biomaterial as an implant is strongly determined by the nanotopography size triggering the ideal cell response. Here, nanoporous topography on 304L stainless steel substrates was engineered to identify the nanotopography size causing a transition in the cellular characteristics, and accordingly, the design of nanostructured stainless steel surface as orthopedic implants is proposed. A variety of nanopore diameters ranging from 100 to 220 nm were fabricated by one-step electrolysis process and collectively referred to as artificial microenvironments. Control over the nanopore diameter was achieved by varying bias voltage. MG63 osteoblasts were cultured on the nanoporous surfaces for different days. Immunofluorescence (IF) and scanning electron microscopy (SEM) were performed to compare the modulation in cell morphologies and characteristics. Osteoblasts displayed differential growth parameters and distinct transition in cell behavior after nanopore reached a certain diameter. Nanopores with 100-nm diameter promoted cell growth, focal adhesions, cell area, viability, vinculin-stained area, calcium mineralization, and alkaline phosphatase activity. The ability of these nanoporous substrates to differentially modulate the cell behavior and assist in identifying the transition step will be beneficial to biomedical engineers to develop superior implant geometries, triggering an ideal cell response at the cell-nanotopography interface.

Temporal Control of Osteoblast Cell Growth and Behavior Dictated by Nanotopography and Shear Stress.

Biomaterial design involves assessment of cellular response to nanotopography parameters such as shape, dimension of nanotopography features. Here, the effect of nanotopography alongside the in vivo factor, shear stress, on osteoblast cell behavior, is reported. Tantalum oxide nanodots of 50 or 100 nm diameter were engineered using anodized aluminum oxide as a template. Bare tantalum nitride coated silicon substrates were taken as control (flat). MG63 (osteoblast) cells were seeded for 72 hours on flat, 50 or 100 nm nanodots and modulation in cell morphology, cell viability and expression of integrins was studied. Cells displayed a well-extended morphology on 50 nm nanodots in contrast to an elongated morphology on 100 nm nanodots, as observed by scanning electron microscopy and immunofluorescence staining, thereby confirming the cellular response to different nanotopographies. Based on quantitative real-time polymerase chain reaction data, a greater fold change in the expression of α1 , α2 , α3 , α8 , α9 , [Formula: see text], ß1 , ß4 , ß5 , ß7 and ß8 integrins was observed in cells cultured on 100 nm than on 50 nm nanodots. Moreover, in the presence of a shear stress of 2 dyne/cm2, a 52% increase in the cell viability after culturing the cells for 72 hours was observed on 100 nm nanodots as compared to 50 nm nanodots, thereby validating the effect of shear stress on cell behavior. Duration-of-culture experiments revealed 100 nm nanodots to be an ideal nanotopography choice to engineer optimized implant geometries for an ideal cell response. This study highlights the in vivo factors which need to be considered while designing nanotopographies for in vivo applications, for an ideal response as the cell-nanomaterial interface. Applications in the field of Biomedical, tissue engineering and cancer research are expected.