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The demand for synthetic biomaterials in medical devices, pharmaceutical products and, tissue replacement applications are growing steadily due to aging population worldwide. The use ...for patient matched devices is also increasing due to availability and integration of new technologies. Applications of additive manufacturing (AM) or 3D printing (3DP) in biomaterials have also increased significantly over the past decade towards traditional as well as innovative next generation Class I, II and III devices. In this review, we have focused our attention towards the use of AM in surface modified biomaterials to enhance their in vitro and in vivo performances. Specifically, we have discussed the use of AM to deliberately modify the surfaces of different classes of biomaterials with spatial specificity in a single manufacturing process as well as commented on the future outlook towards surface modification using AM.
It is widely understood that the success of implanted medical devices depends largely on favorable material-tissue interactions. Additive manufacturing has gained traction as a viable and unique approach to engineered biomaterials, for both bulk and surface properties that improve implant outcomes. This review explores how additive manufacturing techniques have been and can be used to augment the surfaces of biomedical devices for direct clinical applications.
Sol-gel coating hydroxyapatite (HA) allows for non-line-of-sight coatings on metallic implants that enhance biocompatibility and osseointegration, but coatings are on the order of a few microns thick ...and have poor adhesion, especially at low sintering temperatures; Both issues can limit implant longevity. In order to improve coating adhesion strength, a titania nanotube interface was used to reduce thermal mismatch and provide a nano-scale surface morphology for mechanical interlocking, while multiple dip-coatings achieved coating thicknesses >70 μm. In this study, Ti-6Al-4V disks were anodized to produce self-assembled titania (TiO2) nanotubes (NTs) on the surface of the substrates, while HA sol-gel was used to dip-coat the samples. The titania layers measured 800–900 nm thick, with nanotube pore widths of 90 ± 12 nm. Pure HA coating thicknesses were measured at 73.3 ± 10.5 μm and 84.97 ± 18.1 μm for polished Ti-6Al-4 V and anodized Ti-6Al-4V, respectively. The adhesion strengths of pure HA coatings on anodized (NT) surfaces were significantly higher (P < 0.05, N = 7) than polished surfaces at 19.02 ± 3.36 MPa and 13.8 ± 3.28, respectively. Strontium was doped into sol-gel coatings (Sr-Sol) to enhance bioactivity and showed a significant increase in preosteoblast MTT optical density after 3 days of culture compared to pure HA sol-gel, and plasma sprayed pure HA and strontium-HA (Sr-HA). SEM imaging showed well attached osteoblast cells with a similar morphology of multiple, long filopodia across all samples. This study shows that forming titania nanotubes through anodization is a viable approach to increase the adhesion strength of sol-gel coatings sintered at low temperatures, and demonstrates a facile method to incorporate dopants that enhance the osteoconductivity of HA sol-gels.
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•TiO2 nanotube layers significantly increase adhesion strength of HA sol-gel coatings•Strontium dopant can be incorporated into coatings during sol-gel synthesis•Doped sol-gel coatings enhanced osteoblast activity over plasma-sprayed coatings
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In this study, we explored a ternary dopant system utilizing 0.25 wt% ZnO to induce osteogenesis, 0.5 wt% SiO2 to induce angiogenesis, and 2.0 wt% Ag2O to provide secondary infection ...control within a plasma assisted hydroxyapatite coating for orthopaedic or dental applications. The objective of this study was to understand the effects of ZnO, SiO2, and Ag2O dopants on the mechanical and biological properties of hydroxyapatite (HA) coatings on titanium (Ti). Coatings were deposited using a 30 kW plasma spray system equipped with a supersonic nozzle to produce above standard coating bond strengths of 24 ± 2 MPa on Ti6Al4V and 22 ± 1 MPa on commercially pure Ti substrates. Antibacterial properties were revealed in vitro against E. coli and S. aureus. The ternary dopant system was implanted in 18 male Sprague-Dawley rats with timepoints of 5 and 10 weeks. By week 5, ZnSiAg-HA produced 32% bone mineralization of 68% total bone formation compared to only 11% bone mineralization of 55% total bone formation in the undoped coating. This system can be employed for replacement surgeries and revision surgeries to reduce healing time and enhance osseointegration.
Total hip replacements increased 124% from 2000 to 2010 with an ever-increasing rate due to the rise in average life span and an escalation in surgeries for young patients. Replacement surgeries come with the risk of rejection, poor integration, and infection. This study incorporates biologically relevant metallic oxides of ZnO, SiO2, and Ag2O within a hydroxyapatite coating on titanium deposited using a radio frequency induction plasma spray. A ternary dopant system has not been explored in the current literature and little is known about these particular dopants in vivo. This proposed system can be employed for replacement surgeries to lower healing time and enhance osseointegration between implant and host tissue.
Growing demand in bone tissue replacement has shifted treatment strategy from pursuing traditional autogenous and allogeneic grafts to tissue replacement with bioactive biomaterials. Constructs that ...exhibit the ability to support the bone structure while encouraging tissue regeneration, integration, and replacement represent the future of bone tissue engineering. The present study aimed to understand the osteogenic and mechanical effects of binder jet 3D printed, porous β-tricalcium phosphate scaffolds modified with a natural polymer/drug coating of polydopamine and Cissus Quadrangularis extract. Compression testing was used to determine the effect the polydopamine coating process had on the mechanical strength of the scaffolds. 3D printed scaffolds with and without polydopamine coatings fractured at 3.88 ± 0.51 MPa and 3.84 ± 1 MPa, respectively, suggesting no detrimental effect on strength due to the coating process. The osteogenic potential of the extract-loaded coating was tested in vitro, under static and dynamic flow conditions, and in vivo in a rat distal femur model. Static osteoblast cultures indicated polydopamine-coated samples with and without the extract exhibited greater proliferation after 3 days (p < 0.05). Similarly, polydopamine resulted in increased proliferation and alkaline phosphatase expression under dynamic flow, but alkaline phosphatase expression was significantly enhanced (p < 0.05) only in samples treated with the extract. Histological analysis of implanted scaffolds showed substantially more new bone growth throughout the implant pores at 4 weeks post-op in polydopamine and extract-loaded implants compared to pure β-tricalcium phosphate. These results indicated that implants coated with polydopamine and Cissus Quadrangularis extract facilitated osteoblast proliferation and alkaline phosphatase production and improved early bone formation and ingrowth while maintaining mechanical strength.
•Fabricated 3D printed β-tricalcium phosphate bone scaffolds coated with polydopamine + Cissus Quadrangularis .•Scaffolds coated with higher concentrations of dopamine experienced less degradation.•Polydopamine aided drug release in physiological and acidic conditions.•Polydopamine + Cissus Quadrangularis increased proliferation and alkaline phosphatase production under perfusion.•Polydopamine + CissusQuadrangularis coated implants demonstrated improved in vivo new bone formation.
The aim of this study was to quantify and predict relationships between rating of perceived exertion (RPE) and GPS training-load (TL) variables in professional Australian football (AF) players using ...group and individualized modeling approaches.
TL data (GPS and RPE) for 41 professional AF players were obtained over a period of 27 wk. A total of 2711 training observations were analyzed with a total of 66 ± 13 sessions/player (range 39-89). Separate generalized estimating equations (GEEs) and artificial-neural-network analyses (ANNs) were conducted to determine the ability to predict RPE from TL variables (ie, session distance, high-speed running HSR, HSR %, m/min) on a group and individual basis.
Prediction error for the individualized ANN (root-mean-square error RMSE 1.24 ± 0.41) was lower than the group ANN (RMSE 1.42 ± 0.44), individualized GEE (RMSE 1.58 ± 0.41), and group GEE (RMSE 1.85 ± 0.49). Both the GEE and ANN models determined session distance as the most important predictor of RPE. Furthermore, importance plots generated from the ANN revealed session distance as most predictive of RPE in 36 of the 41 players, whereas HSR was predictive of RPE in just 3 players and m/min was predictive of RPE in just 2 players.
This study demonstrates that machine learning approaches may outperform more traditional methodologies with respect to predicting athlete responses to TL. These approaches enable further individualization of load monitoring, leading to more accurate training prescription and evaluation.
A high level of participant skill is influential in determining the outcome of many sports. Thus, tests assessing skill outcomes in sport are commonly used by coaches and researchers to estimate an ...athlete's ability level, to evaluate the effectiveness of interventions or for the purpose of talent identification.
The objective of this systematic review was to examine the methodological quality, measurement properties and feasibility characteristics of sporting skill outcome tests reported in the peer-reviewed literature.
A search of both SPORTDiscus and MEDLINE databases was undertaken.
Studies that examined tests of sporting skill outcomes were reviewed. Only studies that investigated measurement properties of the test (reliability or validity) were included. A total of 22 studies met the inclusion/exclusion criteria.
A customised checklist of assessment criteria, based on previous research, was utilised for the purpose of this review.
A range of sports were the subject of the 22 studies included in this review, with considerations relating to methodological quality being generally well addressed by authors. A range of methods and statistical procedures were used by researchers to determine the measurement properties of their skill outcome tests. The majority (95%) of the reviewed studies investigated test-retest reliability, and where relevant, inter and intra-rater reliability was also determined. Content validity was examined in 68% of the studies, with most tests investigating multiple skill domains relevant to the sport. Only 18% of studies assessed all three reviewed forms of validity (content, construct and criterion), with just 14% investigating the predictive validity of the test. Test responsiveness was reported in only 9% of studies, whilst feasibility received varying levels of attention.
In organised sport, further tests may exist which have not been investigated in this review. This could be due to such tests firstly not being published in the peer-review literature and secondly, not having their measurement properties (i.e., reliability or validity) examined formally.
Of the 22 studies included in this review, items relating to test methodological quality were, on the whole, well addressed. Test-retest reliability was determined in all but one of the reviewed studies, whilst most studies investigated at least two aspects of validity (i.e., content, construct or criterion-related validity). Few studies examined predictive validity or responsiveness. While feasibility was addressed in over half of the studies, practicality and test limitations were rarely addressed. Consideration of study quality, measurement properties and feasibility components assessed in this review can assist future researchers when developing or modifying tests of sporting skill outcomes.
Summary On-call work is becoming an increasingly common work pattern, yet the human impacts of this type of work are not well established. Given the likelihood of calls to occur outside regular work ...hours, it is important to consider the potential impact of working on-call on stress physiology and sleep. The aims of this review were to collate and evaluate evidence on the effects of working on-call from home on stress physiology and sleep. A systematic search of Ebsco Host, Embase, Web of Science, Scopus and ScienceDirect was conducted. Search terms included: on-call , on call , standby, sleep , cortisol, heart rate , adrenaline , noradrenaline , nor-adrenaline , epinephrine , norepinephrine , nor-epinephrine , salivary alpha amylase and alpha amylase . Eight studies met the inclusion criteria, with only one study investigating the effect of working on-call from home on stress physiology. All eight studies investigated the effect of working on-call from home on sleep. Working on-call from home appears to adversely affect sleep quantity, and in most cases, sleep quality. However, studies did not differentiate between night’s on-call from home with and without calls. Data examining the effect of working on-call from home on stress physiology were not sufficient to draw meaningful conclusions.
In team sports, tactical periodisation refers to the planned manipulation of training loads with the aim of prioritising athlete readiness for matches of greatest importance. Although monitoring of ...athletes' physical condition is often used to inform this planning, the direct influence of external factors on match difficulty has not been well quantified. In this study, a 'match difficulty index' (MDI) for use in Super Rugby was developed, based on the influence imparted by five external factors on previous match outcomes. Specifically, information relating to match location, days break between matches, time-zone change and opposition ladder position (both current and previous year) were collected for matches played during the 2011-2013 Super Rugby seasons. Logistic regression analyses were used to assess the importance of each of these factors with respect to match outcome (win/loss), with opposition ladder position and match location (home, domestic away or international) exerting the greatest influence on match difficulty. Three separate cross-validated models were constructed, with match outcome classification performance reported as 66.2%, 65.5% and 63.7% respectively. The three MDI models emanating from this study can each be used to inform tactical periodisation program design both prior to and during the regular season.
Bose et al cite that careful tailoring of the chemistry and structure of biomaterials is leading to production of devices that can help repair or replace damaged tissue. Doctors and research ...institutions around the world are now using 3D printing techniques to create custom structures that can help to rebuild or remodel different structures across the entire human body. Creating repairs that can interface with bone is a particularly tricky endeavor. Our group specializes in using 3D printing to improve bone replacements. The manufacturing technique is very different from that used to create early devices, and so are the materials; we use biomaterials to create the implants and replacements.
It has been suggested that young people should develop competence in a variety of 'lifelong physical activities' to ensure that they can be active across the lifespan.
The primary aim of this ...systematic review is to report the methodological properties, validity, reliability, and test duration of field-based measures that assess movement skill competency in lifelong physical activities. A secondary aim was to clearly define those characteristics unique to lifelong physical activities.
A search of four electronic databases (Scopus, SPORTDiscus, ProQuest, and PubMed) was conducted between June 2014 and April 2015 with no date restrictions.
Studies addressing the validity and/or reliability of lifelong physical activity tests were reviewed. Included articles were required to assess lifelong physical activities using process-oriented measures, as well as report either one type of validity or reliability.
Assessment criteria for methodological quality were adapted from a checklist used in a previous review of sport skill outcome assessments.
Movement skill assessments for eight different lifelong physical activities (badminton, cycling, dance, golf, racquetball, resistance training, swimming, and tennis) in 17 studies were identified for inclusion. Methodological quality, validity, reliability, and test duration (time to assess a single participant), for each article were assessed. Moderate to excellent reliability results were found in 16 of 17 studies, with 71% reporting inter-rater reliability and 41% reporting intra-rater reliability. Only four studies in this review reported test-retest reliability. Ten studies reported validity results; content validity was cited in 41% of these studies. Construct validity was reported in 24% of studies, while criterion validity was only reported in 12% of studies.
Numerous assessments for lifelong physical activities may exist, yet only assessments for eight lifelong physical activities were included in this review. Generalizability of results may be more applicable if more heterogeneous samples are used in future research.
Moderate to excellent levels of inter- and intra-rater reliability were reported in the majority of studies. However, future work should look to establish test-retest reliability. Validity was less commonly reported than reliability, and further types of validity other than content validity need to be established in future research. Specifically, predictive validity of 'lifelong physical activity' movement skill competency is needed to support the assertion that such activities provide the foundation for a lifetime of activity.
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