Translating patient needs into medical device development: co-design of a photoprotection visor for Xeroderma Pigmentosum using qualitative interviews.

INTRODUCTION: People with Xeroderma Pigmentosum (XP) have a heightened sensitivity to ultraviolet radiation (UVR) and are advised to wear photoprotective clothing including a visor covering the face and neck. Photoprotective visors are homemade and predominately worn by children with decreasing frequency as age increases. To improve upon the current design and efficacy we were tasked with developing a prototype visor to meet patients' needs. METHODS: Adopting a codesign methodology, patients' experiences of wearing a visor and patient and carer views of emerging prototypes were explored during interviews. A thematic analysis was conducted in parallel with data collection and themes were interpreted into design cues; desirable attributes of a visor that would counteract the negative user experiences and meet the requirements described by patients and carers. The design cues guided the iterative development of prototypes by academic engineers. RESULTS: Twenty-four interviews were conducted with patients and carers. Thematic analysis resulted in the following five themes: Being safe from UVR exposure; self-consciousness; temperature effects; acoustic difficulties; and material properties. The following design cues were developed from the themes respectively; materials and design with high UVR protection; ability to customise with own headwear; ventilation to reduce steaming up; acoustic functionality to enable hearing and speech; foldable, portable, and easy to put on and take off. CONCLUSIONS: It is important to understand people's experiences of using medical devices to improve their safety, efficiency and user satisfaction. The user experience themes and design cues, informed the iterative development of low fidelity visor prototypes as part of a codesign process. These design cues and responses to the prototypes are guiding commercial manufacturing and regulatory approval. The visor can then be prescribed to patients, providing an equitable service of care.

Synthetic Peptides with Inadvertent Chemical Modifications Can Activate Potentially Autoreactive T Cells.

The human CD8+ T cell clone 6C5 has previously been shown to recognize the tert-butyl-modified Bax161-170 peptide LLSY(3-tBu)FGTPT presented by HLA-A*02:01. This nonnatural epitope was likely created as a by-product of fluorenylmethoxycarbonyl protecting group peptide synthesis and bound poorly to HLA-A*02:01. In this study, we used a systematic approach to identify and characterize natural ligands for the 6C5 TCR. Functional analyses revealed that 6C5 T cells only recognized the LLSYFGTPT peptide when tBu was added to the tyrosine residue and did not recognize the LLSYFGTPT peptide modified with larger (di-tBu) or smaller chemical groups (Me). Combinatorial peptide library screening further showed that 6C5 T cells recognized a series of self-derived peptides with dissimilar amino acid sequences to LLSY(3-tBu)FGTPT. Structural studies of LLSY(3-tBu)FGTPT and two other activating nonamers (IIGWMWIPV and LLGWVFAQV) in complex with HLA-A*02:01 demonstrated similar overall peptide conformations and highlighted the importance of the position (P) 4 residue for T cell recognition, particularly the capacity of the bulky amino acid tryptophan to substitute for the tBu-modified tyrosine residue in conjunction with other changes at P5 and P6. Collectively, these results indicated that chemical modifications directly altered the immunogenicity of a synthetic peptide via molecular mimicry, leading to the inadvertent activation of a T cell clone with unexpected and potentially autoreactive specificities.

Increased frequency of CD4+ PD-1+ HLA-DR+ T cells is associated with disease progression in CLL.

Chronic lymphocytic leukaemia (CLL) patients often have abnormal expansions of CD4+ and CD8+ T cells and this can be associated with progressive disease. To characterise the key T-cell populations involved in this phenomenon, we used flow cytometry and 11 phenotypic markers to study 74 CLL patients and 14 controls. T cells of CLL patients were more phenotypically complex than those of healthy controls with significant increases in the frequencies of CD4 and CD8 memory T cells expressing exhaustion-, activation- and senescence-associated markers. Multivariate analysis of 111 different T-cell subsets showed that high frequencies of four subsets (three CD8 and one CD4) were associated with shorter progression-free survival. The most significant association was with CD4+ HLA-DR+ PD-1+ T cells, and patients could be stratified into high- and low-risk groups based on the frequency of these T cells. The expansion of this CD4+ subset could not be accounted for by age, cytomegalovirus infection or increases in Treg cells. Overall, these results highlight two relatively simple biomarkers, percentage CD8+ and percentage CD4+ PD-1+ HLA-DR+ T cells, which can be used to risk-stratify CLL patients, independent of other tumour-associated markers. They also provide further evidence for the pivotal role of T cells in modulating the pathology of CLL.

The design and construction of an electrohydrodynamic cartesian robot for the preparation of tissue engineering constructs.

In this work we bring together replicating rapid prototyping technology with electrohydrodynamic phenomena to develop a device with the ability to build structures in three-dimensions while simultaneously affording the user a degree of designing versatility and ease that is not seen in conventional computer numerically controlled machines. An attempt at reproducing an actual human ear using polycaprolactone was pursued to validate the hardware. Five different polycaprolactone solution concentrations between 7-15 wt% were used and printing was performed at applied voltages that ranged from 1 to 6 kV and at flow rates from 5 µl/min to 60 µl/min. The corresponding geometrical and aesthetic features of the printed constructs were studied to determine the effectiveness of the device. The 15 wt% concentration at 60 µl/min under an applied electric field of 6 kV was identified as the best operating parameters to work with.

Culture surface influence on T-cell phenotype and function.

When dealing with T lymphocyte culture there is currently very less information available about the interaction between T-cells and the culture system. In this study we look at the influence of the culture chamber on T-cell proliferation in two main aspects of the culture system, namely: culture chamber material and geometry. The study was carried out using unique polymeric closed cell culture inserts, which were processed via injection moulding from polystyrene (PS), polycarbonate (PC), polyetherurethane (PEU), polystyrene-co-acrylonitrile (PSAN) and polyetherimide (PEI). Furthermore culture chamber geometry was studied using commercially available 24, 12 and 6-well plates prepared from tissue culture plastic (TCP). For T lymphocyte stimulation two methods were used involving either EBV peptide pools or MACS iBead particles depending on the experiment performed. Culture was done with 1645 RPMI medium supplemented with foetal calf serum, penicillin, streptomycin and rhIL-2. We found four materials out of five we tested (PS, PC, PSAN and PEI) exhibited similar fold expansions with minimal influence on proportions of CD4 and CD8, while PEU had a negative influence on T cell growth along with adversely affected CD4/CD8 proportions. Changes in the geometry of TCP had no effect on T cell growth or maturation rather the size of geometry seems to have more influence on proliferation. T-cells appear to prefer smaller geometries during initial stages of culture while towards the end of the culture size becomes less significant to cell proliferation. The parameters tested in this study have significant influences on T-cell growth and are necessary to consider when designing and constructing expansion systems for antigen specific T lymphocytes. This is important when culturing T-cells for immunotherapeutic applications where antigen specificity, T-cell maturation and function should remain unaffected during culture.