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A label-free microscopy method for assessing the differentiation status of stem cells is presented with potential application for characterization of therapeutic stem cell populations. The microscopy system is capable of characterizing live cells based on the use of evanescent wave microscopy and quantitative phase contrast (QPC) microscopy. The capability of the microscopy system is demonstrated by studying the differentiation of live immortalised neonatal mouse neural stem cells over a 15 day time course. Metrics extracted from microscope images are assessed and images compared with results from endpoint immuno-staining studies to illustrate the system’s performance. Results demonstrate the potential of the microscopy system as a valuable tool for cell biologists to readily identify the differentiation status of unlabelled live cells.

A new imaging contrast agent is reported that provides an increased fluorescent signal upon application of ultrasound (US). Liposomes containing lipids labelled with pyrene were optically excited and the excimer fluorescence emission intensity was detected in the absence and presence of an ultrasound field using an acousto-fluorescence setup. The acousto-fluorescence dynamics of liposomes containing lipids with pyrene labelled on the fatty acid tail group (PyPC) and the head group (PyPE) were compared. An increase in excimer emission intensity following exposure to US was observed for both cases studied. The increased intensity and time constants were found to be different for the PyPC and PyPE systems, and dependent on the applied US pressure and exposure time. The greatest change in fluorescence intensity (130%) and smallest rise time constant (0.33 s) are achieved through the use of PyPC labelled liposomes. The mechanism underlying the observed increase of the excimer emission intensity in PyPC labelled liposomes is proposed to arise from the \"wagging\" of acyl chains which involves fast response and requires lower US pressure. This is accompanied by increased lipid lateral diffusivity at higher ultrasound pressures, a mechanism that is also active in the PyPE labelled liposomes.

Background Understanding the barriers and facilitators to behaviour change by primary care practitioners (PCPs) is vital to inform the design and implementation of successful Behaviour Change Interventions (BCIs), embed evidence-based medicine into routine clinical practice, and improve quality of care and population health outcomes. Methods A theory-led systematic review of reviews examining barriers and facilitators to clinical behaviour change by PCPs in high-income primary care contexts using PRISMA. Embase, MEDLINE, PsychInfo, HMIC and Cochrane Library were searched. Content and framework analysis was used to map reported barriers and facilitators to the Theoretical Domains Framework (TDF) and describe emergent themes. Intervention functions and policy categories to change behaviour associated with these domains were identified using the COM-B Model and Behaviour Change Wheel (BCW). Results Four thousand three hundred eighty-eight reviews were identified. Nineteen were included. The average quality score was 7.5/11. Reviews infrequently used theory to structure their methods or interpret their findings. Barriers and facilitators most frequently identified as important were principally related to ‘ Knowledge ’, ‘ Environmental context and resources ’ and ‘ Social influences ’ TDF domains. These fall under the ‘Capability’ and ‘Opportunity’ domains of COM-B, and are linked with interventions related to education, training, restriction, environmental restructuring and enablement. From this, three key areas for policy change include guidelines, regulation and legislation. Factors least frequently identified as important were related to ‘Motivation’ and other psychological aspects of ‘Capability’ of COM-B. Based on this, BCW intervention functions of persuasion, incentivisation, coercion and modelling may be perceived as less relevant by PCPs to change behaviour. Conclusions PCPs commonly perceive barriers and facilitators to behaviour change related to the ‘Capability’ and ‘Opportunity’ domains of COM-B. PCPs may lack insight into the role that ‘Motivation’ and aspects of psychological ‘Capability’ have in behaviour change and/or that research methods have been inadequate to capture their function. Future research should apply theory-based frameworks and appropriate design methods to explore these factors. With no ‘one size fits all’ intervention, these findings provide general, transferable insights into how to approach changing clinical behaviour by PCPs, based on their own views on the barriers and facilitators to behaviour change. Systematic review registration A protocol was submitted to the London School of Hygiene and Tropical Medicine via the Ethics and CARE form submission on 16.4.2020, ref number 21478 (available on request). The project was not registered on PROSPERO.

Objective The use of benchtop metabolic profiling technology based on nuclear magnetic resonance (NMR) was evaluated in a small cohort of cats with a view to applying this as a viable and rapid metabolic tool to support clinical decision making. Results Urinary metabolites were analysed from four subjects consisting of two healthy controls and two chronic kidney disease (CKD) IRIS stage 2 cases. The study identified 15 metabolites in cats with CKD that were different from the controls. Among them were acetate, creatinine, citrate, taurine, glycine, serine and threonine. Benchtop NMR technology is capable of distinguishing between chronic kidney disease case and control samples in a pilot feline cohort based on metabolic profile. We offer perspectives on the further development of this pilot work and the potential of the technology, when combined with sample databases and computational intelligence techniques to offer a clinical decision support tool not only for cases of renal disease but other metabolic conditions in the future.

Novel sensing technologies for liquid biopsies offer promising prospects for the early detection of metabolic conditions through omics techniques. Indeed, high-field nuclear magnetic resonance (NMR) facilities are routinely used for metabolomics investigations on a range of biofluids in order to rapidly recognise unusual metabolic patterns in patients suffering from a range of diseases. However, these techniques are restricted by the prohibitively large size and cost of such facilities, suggesting a possible role for smaller, low-field NMR instruments in biofluid analysis. Herein we describe selected biomolecule validation on a low-field benchtop NMR spectrometer (60 MHz), and present an associated protocol for the analysis of biofluids on compact NMR instruments. We successfully detect common markers of diabetic control at low-to-medium concentrations through optimised experiments, including α-glucose (≤2.8 mmol/L) and acetone (25 µmol/L), and additionally in readily accessible biofluids, particularly human urine. We present a combined protocol for the analysis of these biofluids with low-field NMR spectrometers for metabolomics applications, and offer a perspective on the future of this technique appealing to ‘point-of-care’ applications.

Quantum technologies are impacting numerous engineering fields, but they are still in their infancy. Challenges lie ahead to ensure that we make the most of these powerful tools. Bringing diverse, multidisciplinary teams together to work through problems will be critical to their success.

Background/Aims: Cognitive impairment is prevalent in older inpatients but may be unrecognized. Screening to identify cognitive deficits is therefore important to optimize care. The 10-point Abbreviated Mental Test Score (AMTS) is widely used in acute hospital settings but its reliability for mild versus more severe cognitive impairment is unknown. We therefore studied the AMTS versus the 30-point Montreal Cognitive Assessment (MoCA) in older (≥75 years) inpatients. Methods: The AMTS and MoCA were administered to consecutive hospitalized patients at ≥72 h after admission in a prospective observational study. MoCA testing time was recorded. Reliability of the AMTS for the reference standard defined as mild (MoCA <26) or moderate/severe (MoCA <18) cognitive impairment was assessed using the area under the receiver-operating curve (AUC). Sensitivity, specificity, positive and negative predictive values of low AMTS (<8) for cognitive impairment were determined. Results: Among 205 patients (mean/SD age = 84.9/6.3 years, 96 (46.8%) male, 74 (36.1%) dementia/delirium), mean/SD AMTS was 7.2/2.3, and mean/SD MoCA was 16.1/6.2 with mean/SD testing time = 17.9/7.2 min. 96/205 (46.8%) had low AMTS whereas 174/185 (94%) had low MoCA: 74/185 (40.0%) had mild and 100 ( 54.0%) had moderate/severe impairment. Moderate/severe cognitive impairment was more prevalent in the low versus the normal AMTS group: 74/83 (90%) versus 25/102 (25%, p < 0.0001). AUC of the AMTS for mild and moderate/severe impairment were 0.86 (95% CI = 0.80–0.93) and 0.88 (0.82–0.93), respectively. Specificity of AMTS <8 for both mild and moderate/severe cognitive impairment was high (100%, 71.5–100, and 92.7%, 84.8–97.3) but sensitivity was lower (44.8%, 37.0–52.8, and 72.8%, 62.6–81.6, respectively). The negative predictive value of AMTS <8 was therefore low for mild impairment (10.9%, 5.6–18.7) but much higher for moderate/severe impairment (75.2%, 65.7–83.3). All MoCA subtests discriminated between low and normal AMTS groups (all p < 0.0001, except p = 0.002 for repetition) but deficits in delayed recall, verbal fluency and visuo-executive function were prevalent even in the normal AMTS group. Conclusion: The AMTS is highly specific but relatively insensitive for cognitive impairment: a quarter of those with normal AMTS had moderate/severe impairment on the MoCA with widespread deficits. The AMTS cannot therefore be used as a “rule-out” test, and more detailed cognitive assessment will be required in selected patients.

Hydrogels are playing an increasing role in regenerative medicine owing to their growing functional sophistication. This is being underpinned by advances in hydrogel synthesis, particularly through molecular and genetic engineering, which provide greater control of hydrogel structure and hence the emergence of hydrogels with new functionalities. In order to exploit this capability it is necessary to fully understand the relationship between hydrogel structure and function. This article will investigate the nature of hydrogel-structure relationships by: highlighting the key attributes of hydrogels that modulate their function, discussing the link between these attributes and hydrogel behavior, and identifying possible measurement strategies to elucidate them.

Tissue engineering is a rapidly growing field that aims to develop biological substitutes that restore, maintain or improve tissue function. The focus of research to date has been the underlying biology required for tissue-engineered therapies. However, as tissue-engineered products reach the marketplace, there is a pressing need for an improved understanding of the engineering and economic issues associated with them. This is motivated by the lack of commercial viability of many of the initial therapies that have been produced. It has been suggested in the literature that this is partly due to poor process and system design in tissue production, as well as a lack of process monitoring and control. This review argues that principles of design, measurement and process monitoring from the physical sciences are needed to move tissue engineering forward, and that much of the technology needed to realize this is already available.

Polymeric tissue scaffolds are central to many regenerative medicine therapies offering a new approach to medicine. As the number of these regenerative therapies increases there is a pressing need for an improved understanding of the methods of scaffold fabrication. Of the many approaches to processing scaffolds, supercritical fluid fabrication methods have a distinct advantage over other techniques as they do not require the use of organic solvents, elevated processing temperatures or leaching processes. The work presented here is centred on the development of a new approach to monitoring supercritical scaffold fabrication based on determination of the scaffold acoustic impedance to inform protocols for scaffold fabrication. The approach taken uses an ultrasonic pulse-echo reflectometer enabling non-invasive monitoring of the supercritical environment on-line. The feasibility of this approach was investigated for two scaffolds of different molecular weight. Acoustic results demonstrate that differences in the physical properties of the two scaffolds could be resolved, particularly during the foaming process which correlated with findings from time-lapsed imaging and micro X-ray computed tomography (μ X-ray CT) images. Thus, this work demonstrates the feasibility of ultrasonic pulse-echo reflectometry to non-invasively study supercritical scaffold fabrication on-line providing a greater understanding of the scaffold fabrication process.