Using knowledge discovery through data mining to gain intelligence from routinely collected incident reporting in an acute English hospital.

PURPOSE: Incident reporting systems are commonly deployed in healthcare but resulting datasets are largely warehoused. This study explores if intelligence from such datasets could be used to improve quality, efficiency, and safety. DESIGN/METHODOLOGY/APPROACH: Incident reporting data recorded in one NHS acute Trust was mined for insight (n = 133,893 April 2005-July 2016 across 201 fields, 26,912,493 items). An a priori dataset was overlaid consisting of staffing, vital signs, and national safety indicators such as falls. Analysis was primarily nonlinear statistical approaches using Mathematica V11. FINDINGS: The organization developed a deeper understanding of the use of incident reporting systems both in terms of usability and possible reflection of culture. Signals emerged which focused areas of improvement or risk. An example of this is a deeper understanding of the timing and staffing levels associated with falls. Insight into the nature and grading of reporting was also gained. PRACTICAL IMPLICATIONS: Healthcare incident reporting data is underused and with a small amount of analysis can provide real insight and application to patient safety. ORIGINALITY/VALUE: This study shows that insight can be gained by mining incident reporting datasets, particularly when integrated with other routinely collected data.

Variation in job titles within the nursing workforce.

AIMS AND OBJECTIVES/BACKGROUND: The work of specialist nursing has been under scrutiny for many years in the UK due to a perception that it is not cost-effective. A common issue is the lack of consistency of job titles, which causes confusion to the public, employing organisations, colleagues and commissioners of services. Lack of consistency has implications for the wider perception of advanced specialist practice in the worldwide community and the workforce more generally. This study aims to understand the variation in job titles in the UK population. METHODS: A pre-existing data set of accrued studies into the work of nurses working in specialisms was mined for insight (N = 17,960). This study used knowledge discovery through data and descriptive statistics to perform secondary analysis. RESULTS: Mining these data revealed 595 job titles in use in 17,960 specialist posts once the specialism had been removed. The most commonly used titles were Clinical Nurse Specialist, Nurse Specialist/Specialist Nurse, Advanced Nurse Practitioner and Nurse Practitioner. There were three other primary groupings. These were variants with a specialist or technical prefix of suffix, for example Nurse Endoscopist, variants of seniority such as trainee, senior nurse for [specialism] or variants of function such as Nurse Prescriber. The clustering was driven primarily by pay band. A total of 323 posts were recorded as holding titles such as Advanced Nurse Practitioner or Specialist Nurse who were not registered with the Nursing & Midwifery Council. RELEVANCE TO CLINICAL PRACTICE: In this data set, there is a large array of titles, which appear to have little relationship with other factors like education. This is confusing to the public, employers and those commissioning services. It also demonstrates that the previous assumptions by Council for Healthcare Regulatory Excellence that advanced practice labels are associated with career progression are unsound and should be addressed by the regulator.

Severe asthma: emergency care patient driven solutions.

Purpose Patients with severe asthma were choosing not to use the emergency department (ED) in extremis and were self-medicating when experiencing severe asthma, putting their lives at risk. This local issue reflected a nationwide situation. The purpose of this paper is to better understand the reasons behind patients' reluctance to attend ED and to consider practical solutions in a structured way. Design/methodology/approach Systems thinking (soft systems methodology) was used to examine the issues resulting in this reluctance to attend the ED. Once this tame (well-defined) problem was revealed, a potential solution was developed in co-production with patients. Findings Patients feared attending the ED and felt vulnerable while in the ED for several reasons. This appeared to be a well-defined and solvable problem. The solution proposed was an asthma patient passport (APP), which increased patient's confidence in their ability to communicate their needs while in severe distress. The APP decreases (from 12 to 5 steps) the work patients had to do to achieve care. The APP project is currently being evaluated. Practical implications The APP should be offered to all people with severe asthma. Originality/value By revisiting systems thinking and identifying problems, a solution was identified. Although methods such as soft systems methodology have limitations when used in wicked (difficult or impossible to resolve) problems, such methods still have merit in tame problems and were applicable in this case to fully understand the issues, and to design practical solutions.

A novel method for the extraction and culture of progenitor stem cells from human peripheral blood for use in regenerative medicine.

Human peripheral blood (HPB) contains both circulating endothelial cells (CECs) and endothelial progenitor stem cells (EPCs), which may be suitable for use in regenerative medicine. There has been considerable interest in using these cells, but there is no "gold standard" technique for isolating these cells. The aim of this study was to characterize and compare a number of different extraction and culture techniques to develop a system to isolate and culture cells. EPC and CEC were isolated from HPB using either Histopaque-1077 or Lymphoprep. The two isolation methods were compared for the number of cells isolated, cell metabolism, and RNA expression. Both isolations produced viable cells and were comparable. The tissue culture method employed does have a significant effect on the cell population with regard to medium choice, fetal bovine serum concentration, and surface modification of the culture surface. In conclusion, it can be seen that although this study and previous work can suggest a basis for culture, further work to develop an optimized and agreed "gold standard" culture regime for EPC from HPB is required to maximize the potential of this source of cells for regenerative medicine and to translate its clinical use in the future.

The long-term stability in gene expression of human endothelial cells permits the production of large numbers of cells suitable for use in regenerative medicine.

Tissue engineering has been conducted in the study of cardiovascular grafts for many years. Many obstacles have been overcome in this rapidly changing field, but one difficulty has remained until now: the large number of endothelial cells (ECs) needed for seeding the inner layer of bypass graft. Recent advances in endothelial progenitor cell (EPC) isolation and culture techniques have increased the interest in genetic studies. Despite these advances in EPC studies, the "gold standard" for the seeding of tissue engineering constructs or hybrid grafts remains mature human umbilical vein endothelial cells (HUVECs). This study investigates the ability of HUVECs to be expanded in culture to provide sufficient cells for graft seeding. The levels of gene expression of key genes are then examined to ensure that these cells retain the EC phenotype. This study demonstrates that HUVECs may be cultured for up to 12 passages without alteration in phenotype. Subsequent passage numbers are sufficiently similar to those preceding them to allow cells of different passages to be mixed without gene expression anomalies.

Modeling the Multiple Sclerosis Specialist Nurse Workforce by Determination of Optimum Caseloads in the United Kingdom.

BACKGROUND: It is estimated that there are more than 100,000 people in the United Kingdom who have multiple sclerosis (MS). Patient experience and outcome are improved by access to a specialist nursing service. The aim of this study was to perform demand modeling to understand the need for MS nursing interventions, and thus inform modeling of the future UK MS nursing workforce. METHODS: Existing national data and specific workload and service data were collected from 163 MS specialist nurses who completed a questionnaire on activity and complexity of work both done and left undone. RESULTS: Data were received from across all of the United Kingdom. Twenty-nine percent of respondents were specialist nurses in the field for 3 years or less. Unpaid overtime was regularly performed by 83.4% of respondents. The MS specialist nurse was part of all areas of the patient journey. Areas of work left undone were psychological interventions, physical assessments, social interventions/benefits, and recommending or prescribing medications. CONCLUSIONS: The current recommended caseload of 358 people with MS per full-time equivalent seems to be too high, with a considerable amount of work left undone, particularly psychosocial care. Factors such as travel time, complexity of caseload, changing drug therapies, and societal issues such as the benefits system contributed to driving demand/workload.

In vitro small intestinal epithelial cell growth on a nanocomposite polycaprolactone scaffold.

Tissue engineering of the small intestine remains experimental despite worldwide attempts to develop a functional substitute for short bowel syndrome. Most published studies have reported predominant use of PLLA (poly-L-lactide acid)/PGA (polyglycolic acid) copolymer as the scaffold material, and studies have been limited by in vivo experiments. This lack of progress has inspired a fresh perspective and provoked further investigation and development in this field of tissue engineering. In the present paper, we exploit a relatively new nanocomposite of POSS (polyhedral oligomeric silsesquioxane) and PCL [poly(caprolactone-urea)urethane] as a material to develop porous scaffolds using a solvent casting/particulate leaching technique to fabricate porous scaffolds in different pore sizes and porosities. Scaffolds were characterized for pore morphology and porosity using scanning electron microscopy and micro-computed tomography. Rat intestinal epithelial cells were then seeded on to the polymer scaffolds for an in vitro study of cell compatibility and proliferation, which was assessed by Alamar Blue and lactate dehydrogenase assays performed for 21 days post-seeding. The results obtained demonstrate that POSS-PCL nanocomposite was produced as a macroporous scaffold with porosity over the range of 40-80% and pore size over the range of 150-250 microm. This scaffold was shown to support epithelial cell proliferation and growth. In conclusion, as a further step in investigating small intestinal tissue engineering, the nanocomposite employed in this study may prove to be a useful alternative to poly(lactic-co-glycolic acid) in the future.

Determining acute nurse staffing: a hermeneutic review of an evolving science.

BACKGROUND: Calculating nurse staffing in the acute hospital has become a key issue but solutions appear distant. Community, mental health and areas such as learning disability nursing have attracted less attention and remain intractable. This review aims to examine current approaches to the issue across many disciplines. DESIGN: The approach taken is iterative and in the form of a hermeneutic review. 769 pieces of evidence were reviewed from across disciplines such as nursing, medicine, engineering, statistics, population science, computer science and mathematics where hospital nurse staffing was the subject of the study. RESULTS: A number of themes emerged. The first iteration showed the predominance of unit base approaches (eg, nurse numbers, ratios, activity and workload) and the second was the development of methodologies. Subsequent iterations examined issues such as demand, safety, nurse education, turnover, patient outcomes, patient or staff satisfaction, workload and activity. The majority of studies examined (n=767) demonstrated some association between staffing (units or type/skill) and various factors such as staff or patient satisfaction, working conditions, safety parameters, outcomes complexity of work achieved, work left undone or other factors. Many potential areas such as operational safety research were not utilised. CONCLUSION: Although the relationship between staffing in acute care and factors such as units, safety or workload is complex, the evidence suggests an interdependent relationship which should only be dismissed with caution. The nature of these relationships should be further examined in order to determine nurse staffing. The body of knowledge appears substantial and complex yet appears to have little impact on policy.

Nursing pay by gender distribution in the UK - does the Glass Escalator still exist?

AIMS AND OBJECTIVES/BACKGROUND: Nursing is a predominantly female profession. This is reflected in the demographic of nursing around the world. Some authors have noted that despite being a gendered profession men are still advantaged in terms of pay and opportunity. The aim of this study was to examine if the so called glass escalator in which men are advantaged in female professionals still exists. DESIGN AND METHOD: Descriptive statistics of the routinely collected national workforce datasets from across the UK central repositories and mining of a bespoke data set that has been curated which focuses on the activity of specialist advanced practice clinical nurses. RESULTS: Even in a gendered occupation such as nursing the advantage of men in terms of pay is apparent with men being over-represented at senior Bands compared to their overall proportion in the UK nursing population. From the bespoke dataset there also seem to be an advantage in term of faster attainment of higher grades from the point of registration. CONCLUSION AND RELEVANCE TO CLINICAL PRACTICE: Reward and remuneration are essential to the workforce. This work reveals a gender differential towards men in higher paid nursing work. The drivers for this are complex and further work is required to determine the factors associated with career progression with men in nursing, and the rate limiting factors with the female workforce.

Endothelial cell retention on a viscoelastic nanocomposite vascular conduit is improved by exposure to shear stress preconditioning prior to physiological flow.

In this study, endothelial cell (EC)-seeded nanocomposite grafts were preconditioned with 1-2 dynes/cm(2) in vitro to establish whether low shear stress resulted in improved cell adherence prior to physiological shear stress (15 dynes/cm(2)). Alamar blue cell viability was assessed. Polymerase chain reaction was conducted for glyceraldehyde-3-phosphate dehydrogenase, transforming growth factor beta-1 (TGFbeta-1), vascular endothelial growth factor receptor-1 (VEGFR-1), platelet EC adhesion molecule-1, and vascular endothelial growth factor receptor-2 (VEGFR-2). The Alamar blue results demonstrated improved cellular retention following preconditioning (P < 0.001). VEGFR-2 and TGFbeta-1 expression was up-regulated, and VEGFR-1 down-regulated following preconditioning. This investigation confirms previous findings regarding the potential benefits of preconditioning, and demonstrates that these benefits can be applied to ECs seeded on the nanocomposite employed. It also demonstrates further the suitability and potential of nanocomposite for future use in tissue-engineered cardiovascular devices.

Modelling the Inflammatory Bowel Disease Specialist Nurse Workforce Standards by Determination of Optimum Caseloads in the UK.

BACKGROUND AND AIMS: Crohn's disease and ulcerative colitis are the most common forms of inflammatory bowel disease [IBD], affecting 1 in 250 of the population in the UK. It is accepted that access to a specialist nurse service improves patient experience and outcome. National Standards for the Healthcare of People Who Have Inflammatory Bowel Disease [2013] defined the number of nurse specialists required at 1.5 full time equivalent per 250000 population. The aim of this study was to determine if these standards were being met and to publish a new, robust, validated standard optimising the UK nursing workforce model. METHODS: Existing national data and specific workload and service data were collected from 164 IBD specialist nurses who completed a questionnaire designed to collect information on activity and complexity of work both done and undone. RESULTS: Data were received from all of the UK; 36% of respondents were specialist nurses in the field for 3 years or less. A higher caseload than the recommended level was reported by 63% of respondents. Unpaid overtime was regularly carried out by 84% of respondents. The IBD specialist nurse was involved in all areas of the patient pathway. Areas of work left undone were psychological interventions, prescribing medicines and physical assessments. CONCLUSIONS: Compared with other specialties, IBD specialist nurses are less experienced. It is recommended that the current standard be increased to 2.5 full time equivalent specialist nurses per 250000 patients, to mitigate the increasing complexity of the role, care and the 'rookie' factor.

Crowd medical services in the English Football League: remodelling the team for the 21st century using a realist approach.

OBJECTIVES: To evaluate the new model of providing care based on demand. This included reconfiguration of the workforce to manage workforce supply challenges and meet demand without compromising the quality of care. DESIGN: Currently the Sports Ground Safety Authority recommends the provision of crowd medical cover at English Football League stadia. The guidance on provision of services has focused on extreme circumstances such as the Hillsborough disaster in 1989, while the majority of demand on present-day services is from patients with minor injuries, exacerbations of injuries and pre-existing conditions. A new model of care was introduced in the 2009/2010 season to better meet demand. A realist approach was taken. Data on each episode of care were collected over 14 consecutive football league seasons at Millwall FC divided into two periods, preimplementation of changes and postimplementation of changes. Data on workforce retention and volunteer satisfaction were also collected. SETTING: The data were obtained from one professional football league team (Millwall FC) located in London, UK. PRIMARY AND SECONDARY OUTCOMES: The primary outcome was to examine the demand for crowd medical services. The secondary outcome was to remodel the service to meet these demands. RESULTS: In total, 981 episodes of care were recorded over the evaluation period of 14 years. The groups presenting, demographic and type of presentation did not change over the evaluation. First aiders were involved in 87.7% of episodes of care, nurses in 44.4% and doctors 17.8%. There was a downward trend in referrals to hospital. Workforce feedback was positive. CONCLUSIONS: The new workforce model has met increased service demands while reducing the number of referrals to acute care. It involves the first aid workforce in more complex care and key decision-making and provides a flexible registered healthcare professional team to optimise the skill mix of the team.

The Experiences of Specialist Nurses Working Within the Uro-oncology Multidisciplinary Team in the United Kingdom.

PURPOSE: United Kingdom prostate cancer nursing care is provided by a variety of urology and uro-oncology nurses. The experience of working in multidisciplinary teams (MDT) was investigated in a national study. DESIGN: The study consisted of a national survey with descriptive statistics and thematic analysis. METHODS: A secondary analysis of a data subset from a UK whole population survey was undertaken (n = 285) of the specialist nursing workforce and the services they provide. Data were collected on the experience of working in the MDT. RESULTS: Forty-five percent of the respondents felt that they worked in a functional MDT, 12% felt that they worked in a dysfunctional MDT, and 3.5% found the MDT meeting intimidating. Furthermore, 34% of the nurses felt that they could constructively challenge all members of the MDT in meetings. Themes emerging from open-ended questions were lack of interest in nonmedical concerns by other team members, ability to constructively challenge decisions or views within the meeting, and little opportunity for patients' wishes to be expressed. CONCLUSIONS: Despite expertise and experience, nurses had a variable, often negative, experience of the MDT. It is necessary to ensure that all participants can contribute and are heard and valued. More emphasis should be given to patients' nonmedical needs.

Incorporation of a lauric acid-conjugated GRGDS peptide directly into the matrix of a poly(carbonate-urea)urethane polymer for use in cardiovascular bypass graft applications.

Gly-Arg-Gly-Asp-Ser (GRGDS) was modified by conjugation to lauric acid (LA) to facilitate incorporation into the matrix of a poly(carbonate-urea)urethane (PCU) used in vascular bypass grafts. GRGDS and LA-GRGDS were synthesized using solid phase Fmoc chemistry and characterized by high performance liquid chromatography and Fourier transform infrared spectroscopy. LA-GRGDS was passively coated and incorporated as nanoparticle dispersion on the PCU films. Biocompatibility of the modified surfaces was investigated. Endothelial cells seeded on LA-GRGDS coated and incorporated PCU showed after 48 h and 72 h a significant (p < 0.05) increase in metabolism compared with unmodified PCU. The platelet adhesion and hemolysis studies showed that the modification of PCU had no adverse effect. In conclusion, LA-conjugated RGD derivatives, such as LA-GRGDS, that permit solubility into solvents used in solvent casting methodologies should have wide applicability in polymer development for use in coronary, vascular, and dialysis bypass grafts, and furthermore scaffolds utilized for tissue regeneration and tissue engineering.

Is there an alternative to systemic anticoagulation, as related to interventional biomedical devices?

To reduce the toxic effects, related clinical problems and complications such as bleeding disorders associated with systemic anticoagulation, it has been hypothesized that by coating the surfaces of medical devices, such as stents, bypass grafts, extracorporeal circuits, guide wires and catheters, there will be a significant reduction in the requirement for systemic anticoagulation or, ideally, it will no longer be necessary. However, current coating processes, even covalent ones, still result in leaching followed by reduced functionality. Alternative anticoagulants and related antiplatelet agents have been used for improvement in terms of reduced restenosis, intimal hyperphasia and device failure. This review focuses on existing heparinization processes, their application in clinical devices and the updated list of alternatives to heparinization in order to obtain a broad overview, it then highlights, in particular, the future possibilities of using heparin and related moieties to tissue engineer scaffolds.

Mining routinely collected acute data to reveal non-linear relationships between nurse staffing levels and outcomes.

OBJECTIVES: Nursing is a safety critical activity but not easily quantified. This makes the building of predictive staffing models a challenge. The aim of this study was to determine if relationships between registered and non-registered nurse staffing levels and clinical outcomes could be discovered through the mining of routinely collected clinical data. The secondary aim was to examine the feasibility and develop the use of 'big data' techniques commonly used in industry for this area of healthcare and examine future uses. SETTING: The data were obtained from 1 large acute National Health Service hospital trust in England. Routinely collected physiological, signs and symptom data from a clinical database were extracted, imported and mined alongside a bespoke staffing and outcomes database using Mathmatica V.10. The physiological data consisted of 120 million patient entries over 6 years, the bespoke database consisted of 9 years of daily data on staffing levels and safety factors such as falls. PRIMARY AND SECONDARY OUTCOMES: To discover patterns in these data or non-linear relationships that would contribute to modelling. To examine feasibility of this technique in this field. RESULTS: After mining, 40 correlations (p<0.00005) emerged between safety factors, physiological data (such as the presence or absence of nausea) and staffing factors. Several inter-related factors demonstrated step changes where registered nurse availability appeared to relate to physiological parameters or outcomes such as falls and the management of symptoms. Data extraction proved challenging as some commercial databases were not built for extraction of the massive data sets they contain. CONCLUSIONS: The relationship between staffing and outcomes appears to exist. It appears to be non-linear but calculable and a data-driven model appears possible. These findings could be used to build an initial mathematical model for acute staffing which could be further tested.

Interactions between endothelial cells and a poly(carbonate-silsesquioxane-bridge-urea)urethane.

We have recently developed a polymer which contains silsesquioxane in the form of nano-bridges poly(carbonate-silsesquioxane-bridge-urea)urethane (PCBSU) for cardiovascular device applications. The polymer has been characterised and the durability has been confirmed with long-term in vivo tests. The aim of this study was to test the cytocompatibility of the new polymer and to investigate any potential cytotoxic effects. To assess the effect of direct contact with PCBSU sections of polymer material were cut and placed into a 24-well plate. Six discs were seeded with 2 x 10(5) human umbilical vein cells (HUVEC). As a positive control, six wells were seeded with the same number of HUVEC. In a further experiment to assess indirect contact with PCBSU a sample of the polymer was powdered using a Micro-Dismembrator. Cell culture medium was exposed to powdered polymer (1-100 mg/ml) for a period of 7 days. HUVEC seeded as above were then exposed to the treated cell culture medium for 24 and 96 h. Finally, cell proliferation was studied over 16 days by seeding 2 x 10(5) HUVEC on films of PCBSU cast in glass Petri dishes. Cell viability and growth were assessed using Alamar blue, lactate dehydrogenase and Pico green assays and morphology was studied by Toluidine blue staining and scanning electron microscopy. Viable cells were demonstrated to be present after 16 days seeded on PCBSU. Exposing cells to PCBSU-treated cell culture medium resulted in no apparent damage to the cells at concentrations of 1 or 10 mg/ml, and only a slight reduction at 100 mg/ml after 96 h exposure. This study demonstrates that PCBSU can support the growth of endothelial cells for a prolonged period and does not demonstrate any significant toxic effects to cells. Thus it has the potential to be used both as a medical device and as scaffolding in tissue engineering applications.

Development of an RNA isolation procedure for the characterisation of human endothelial cell interactions with polyurethane cardiovascular bypass grafts.

To date no reliable method has been developed for the isolation of RNA from cells seeded onto cylindrical vascular grafts. This study was performed in order to develop a reliable methodology for isolating RNA from cylindrical conduits made from poly(carbonate-urea)urethane (PU). Human umbilical vein EC were seeded onto PU vascular grafts and an Alamar blue assay performed to assess cell viability. Cells were prepared for RNA extraction by trypsinisation, cell scraping and direct application of cell lysis buffer. In all cases RNA was extracted using a "Qiagen RNeasy" kit. Alamar blue showed viable cells were present on all of the seeded PU vascular grafts. Levels of RNA extracted from the cells removed from the graft by the trypsinisation yielded 0.130 microg/microl, by scraping 0.078 microg/microl and by direct lysing 0.093 microg/microl of RNA, respectively. RTPCR was conducted successfully for GAPDH and TGF-beta1. Trypsinisation prior to RNA extraction provided the highest RNA yield and attained near complete cell removal ensuring that gene expression obtained was representative.

Development of a hybrid cardiovascular graft using a tissue engineering approach.

Tissue engineering of endothelial cells (EC) and chemical engineering with anticoagulant moieties has been undertaken in order to improve prosthetic graft patency and thrombogenicity. This was done by covalently bonding a compliant poly(carbonate-urea)urethane graft (MyoLink) with arginine-glycine-aspartate (RGD) or/and heparin (Hep) to ascertain whether EC retention could be improved. The retention of these moieties and EC was assessed after exposure to pulsatile flow. We covalently bonded RGD, Hep, and RGD/Hep onto the luminal surface of MyoLink using spacer arm technology. Narrow-beam X-ray photoelectron spectroscopy was carried out to check the efficiency of the bonding. EC were radiolabeled and seeded onto native MyoLink and with 1) RGD-, 2) Hep-, and 3) RGD/Hep-bonded grafts and exposed to shear stress in a physiological flow circuit for 6 h, which reproduces femoral artery flow waveforms and pulsatility. Results were recorded on a gamma camera imaging system. Viability of cells was tested with a modified Alamar Blue assay (ABA) and scanning electron microscopy for morphological appearance of seeded cells. Experiments were repeated (n=6). RGD, Hep, and RGD/Hep were bonded together in a uniform distribution on the luminal surface of each graft type, and bioactivity of each moiety covalently bonded was very high. In the flow circuit, there was exponential cell retention for the first 60 min of flow for all the grafts, but after 6 h of exposure to pulsatile flow the RGD/Hep-bonded graft had a significantly better cell retention rate than native MyoLink (75.7%+/-2.3 vs. 60.5+/-10.1, P<0.05). ABA test showed that all the seeded cells postexposure to flow were viable, and significantly higher metabolic activity was recorded on a RGD/Hep-bonded graft than with MyoLink-seeded graft (P<0.01). Using RGD/Hep covalently bonded onto graft surfaces improves cell retention and provides an antithrombogenic surface for initial blood flow in vivo until full EC activity develops postseeding. This would allow the development and further improvement of hybrid grafts.

Effects of sterilization treatments on bulk and surface properties of nanocomposite biomaterials.

With the continuous and expanding use of implantable biomaterials in a clinical setting, this study aims to elucidate the influence of sterilization techniques on the material surface and bulk properties of two polyurethane nanocomposite biomaterials. Both solid samples and porous membranes of nondegradable polyhedral oligomeric silsesquioxane poly(carbonate-urea) urethane (POSS-PCU) and a biodegradable poly(caprolactone-urea) urethane (POSS-PCL) were examined. Sterilization techniques included conventional steam sterilization (autoclaving), gamma irradiation, and disinfection via incubating with ethanol (EtOH) for 10 min or 24 h. After treatment, the samples were examined using gel permeation chromatography (GPC), attenuated total reflectance Fourier transform infrared spectroscopy, and tensiometry. Cytotoxicity was evaluated through the culture of endothelial progenitor cells and the efficacy of sterilization method was determined by incubating each sample in tryptone soya broth and fluid thioglycollate medium for cultivation of microorganisms. Although EtOH did not affect the material properties in any form, the samples were found to be nonsterile with microbial growth detected on each of the samples. Gamma irradiation was not only effective in sterilizing both POSS-PCU and POSS-PCL but also led to minor material degradation and displayed a cytotoxic effect on the cultured cells. Autoclaving was found to be the optimal sterilization technique for both solid and porous membranes of the nondegradable POSS-PCU samples as it was successful in sterilizing the samples, displayed no cytotoxic side effects and did not degrade the material. However, the biodegradable POSS-PCL was not able to withstand the harsh environment during autoclaving, resulting in it losing all structural integrity.