Tunable Light-Responsive Polyurethane-urea Elastomer Driven by Photochemical and Photothermal Coupling Mechanism.

Light-driven soft actuators based on photoresponsive materials can be used to mimic biological motion, such as hand movements, without involving rigid or bulky electromechanical actuations. However, to our knowledge, no robust photoresponsive material with desireable mechanical and biological properties and relatively simple manufacture exists for robotics and biomedical applications. Herein, we report a new visible-light-responsive thermoplastic elastomer synthesized by introducing photoswitchable moieties (i.e., azobenzene derivatives) into the main chain of poly(ε-caprolactone) based polyurethane urea (PAzo). A PAzo elastomer exhibits controllable light-driven stiffness softening due to its unique nanophase structure in response to light, while possessing excellent hyperelasticity (stretchability of 575.2%, elastic modulus of 17.6 MPa, and strength of 44.0 MPa). A bilayer actuator consisting of PAzo and polyimide films is developed, demonstrating tunable bending modes by varying incident light intensities. Actuation mechanism via photothermal and photochemical coupling effects of a soft-hard nanophase is demonstrated through both experimental and theoretical analyses. We demonstrate an exemplar application of visible-light-controlled soft "fingers" playing a piano on a smartphone. The robustness of the PAzo elastomer and its scalability, in addition to its excellent biocompatibility, opens the door to the development of reproducible light-driven wearable/implantable actuators and lightweight soft robots for clinical applications.

Self-reported throat symptoms in Ehlers-Danlos syndromes and hypermobility spectrum disorders: A cross-sectional survey study.

Objectives: This study identified the frequency and severity of dysphagia, dysphonia, and laryngopharyngeal reflux symptoms in people with Ehlers-Danlos syndromes (EDS) or hypermobility spectrum disorders (HSD) and explored differences between diagnostic groups. Methods: Participants were recruited via non-probability convenience sampling. Information was gathered via online survey, including the Reflux Symptom Index (RSI; Belafsky et al., J Voice. 2002;16:274-277), the Eating and Drinking Assessment Tool (EAT-10; Belafsky et al., Ann Otol Rhinol Laryngol. 2008;117:919-924), and the Voice Handicap Index (VHI; Jacobson et al., Am J Speech Lang Pathol. 1997;6(3):66-70). These were analyzed using ANOVAs. Results: There were 1620 participants (96.6% female, 2.8% male) that met the inclusion criteria. The mean age was 38.09 (SD 12.22). 75.51% had hypermobile EDS (hEDS), 17.83% had HSD and 3.33% had classic EDS (cED). The cohort's mean scores were RSI = 22.95 (SD 9.01), EAT-10 = 11.91 (SD 9.66), and VHI score = 31.99 (SD 24.36). The hEDS group had significantly higher mean scores than the HSD group on RSI score and on some RSI items, on EAT-10 score and on all EAT-10 items, and on one VHI item. Conclusion: People with EDS/HSD experience symptoms of acid reflux, dysphagia, and dysphonia to varying degrees with significant differences between hEDS than HSD. Awareness of the impact of EDS/HSD on throat symptoms will enable health care professionals to anticipate throat symptoms more readily in this population, providing individualized and effective management plans. Level of Evidence: IV.

Barriers to research progress for perioperative care practitioners working in cardiothoracic surgery.

Policy and research literature worldwide support the need to build research capacity and capability among non-medical practitioners within healthcare systems. However, there exists a paucity of evidence on whether practitioners in cardiothoracic surgery are attuned to this and on what barriers or enablers exist. A survey was carried out with non-medical practitioners working in cardiothoracic surgery in the United Kingdom to explore attitudes towards health research and audit, and to identify current challenges and barriers to surgical research and audit as perceived by cardiothoracic nurses and allied health professionals. A total of 160 completed questionnaires were returned. 99% of respondents supported the need for research and believed that evidence-based surgical care improves outcomes for patients. Seventy-two percent reported that their employer motivates them to take part in national research or audit but, only 22% were allocated time to do so within their role; 96% reported their interest in being involved in research and audit, yet only 30% believed they had the skills to undertake research, and 96% reported needing additional training. More work is needed to increase awareness, capacity and capability among cardiothoracic surgery care practitioners, and indeed other specialities to achieve research progress.

Changing from face-to-face to virtual meetings due to the COVID-19 pandemic: protocol for a mixed-methods study exploring the impact on cancer multidisciplinary team (MDT) meetings.

INTRODUCTION: In the UK, the National Cancer Plan (2000) requires every cancer patient's care to be reviewed by a multidisciplinary team (MDT). Since the introduction of these guidelines, MDTs have faced escalating demands with increasing numbers and complexity of cases. The COVID-19 pandemic has presented MDTs with the challenge of running MDT meetings virtually rather than face-to-face.This study aims to explore how the change from face-to-face to virtual MDT meetings during the COVID-19 pandemic may have impacted the effectiveness of decision-making in cancer MDT meetings and to make recommendations to improve future cancer MDT working based on the findings. METHODS AND ANALYSIS: A mixed-methods study with three parallel phases:Semistructured remote qualitative interviews with ≤40 cancer MDT members.A national cross-sectional online survey of cancer MDT members in England, using a validated questionnaire with both multiple-choice and free-text questions.Live observations of ≥6 virtual/hybrid cancer MDT meetings at four NHS Trusts.Participants will be recruited from Cancer Alliances in England. Data collection tools have been developed in consultation with stakeholders, based on a conceptual framework devised from decision-making models and MDT guidelines. Quantitative data will be summarised descriptively, and χ2 tests run to explore associations. Qualitative data will be analysed using applied thematic analysis. Using a convergent design, mixed-methods data will be triangulated guided by the conceptual framework.The study has been approved by NHS Research Ethics Committee (London-Hampstead) (22/HRA/0177). The results will be shared through peer-reviewed journals and academic conferences. A report summarising key findings will be used to develop a resource pack for MDTs to translate learnings from this study into improved effectiveness of virtual MDT meetings.The study has been registered on the Open Science Framework (https://doi.org/10.17605/OSF.IO/D2NHW).

The Impact of Personal Protective Equipment on Speech Discrimination and Verbal Communication in the Operating Room and the Role of Audio Communication Devices.

INTRODUCTION: Recent work has highlighted communication difficulties when wearing personal protective equipment (PPE) in the clinical setting, but currently, there are little objective data on its effects. We assessed the impact of PPE on verbal communication in a simulated operating room and evaluated use of an audio communication device. METHODOLOGY: Frontline health professionals across specialties including surgery, anesthetics, and nursing undertook speech discrimination testing with and without standardized levels of PPE in a simulated operating room environment. Background noise (30- and 70-a-weighted decibel multitalker babble) at 2 distances (2 and 4 m) were selected representative of operating room environments. Bamford-Kowal-Bench (BKB) scoring (192 sentences per participant) was performed. A Digital Multichannel Transceiver System (DMTS) was evaluated. We assessed the effects of PPE use, distance, and use of the DMTS with pairwise comparisons, using a Bonferroni correction, and assessed participant experience via Likert scales. RESULTS: Thirty-one healthcare professionals were tested. Without PPE in 70-a-weighted decibel "babble," median BKB sentence scores were 90% and 76% at 2 and 4 m (adjusted P < 0.0005). The median BKB sentence scores dropped to 8% and 4% at 2 and 4 m in PPE (adjusted P < 0.0005). Improved speech discrimination was achieved with DMTS use to 70% and 76% at 2 and 4 m. Personal protective equipment led to a statistically significant reduction in BKB scores across all conditions compared with baseline. Overall participant confidence in PPE clinical communication was low. CONCLUSIONS: Addition of PPE dramatically impairs speech discrimination and communication in high levels of background noise characteristic of clinical environments, which can be significantly improved using DMTS. Measures should be taken by teams through both through reduction of background noise and consideration of assistive technologies maximizing patient safety. This may be further rehearsed in a simulation environment.

Functional Outcomes Following Delayed Laryngeal Reinnervation Of Patients with Vagal Paralysis After Paraganglioma and Schwannoma Surgery.

PURPOSE: We present a prospective case series that aimed to report the functional (voice and swallowing) outcomes of delayed laryngeal reinnervation following vagal interruption by resection of vagal paraganglioma and schwannoma. MATERIALS AND METHODS: A dedicated, anonymized database was established in 2012 with a minimum eighteen-month follow up set for this report. Internationally validated self- and observer-reported measures were recorded preoperatively and at six, 12 and, 18 months together with demographics, diagnoses, and operative details. RESULTS: A total of eight patients with a median age of 46 (37-54) underwent excision of vagal paraganglioma (five) and schwannoma (three) with few mild complications. Three underwent selective and five non selective reinnervation. Seven out of eight patients underwent synchronous injection medialization. The voice handicap index (VHI-30) improved from a baseline median 83 (range 52-102) to 7.5 (5-58) at 18 months; maximum phonation time improved from median 8 (range 5-15) to 10.5 (8.5-11); voice grade ("G" in grade, roughness, breathiness, asthenia, and strain [GRBAS] scoring) improved from median three (severe impairment, range 0-3) to one (mild impairment, 0-2); Eating Assessment Tool (EAT-10) score improved from median 12 (range 3.5-27) preoperatively to one (0-16); and reflux symptom index (RSI) improved from median 25 (range 17-36) to 7 (0-36). One patient exhibited no discernible reinnervation, while the remainder exhibited good cord bulk and tone, though without purposive abduction. CONCLUSION: Delayed laryngeal reinnervation for high vagal paralysis is a safe technique associated with good voice and swallowing outcomes by 12-18 months. Potential confounders in this small series and the absence of a control arm both limit conclusions, but this study suggests that further prospective, controlled studies, and/or case registration are merited.

Cell-intrinsic differences between human airway epithelial cells from children and adults.

The airway epithelium is a protective barrier that is maintained by the self-renewal and differentiation of basal stem cells. Increasing age is a principle risk factor for chronic lung diseases, but few studies have explored age-related molecular or functional changes in the airway epithelium. We retrieved epithelial biopsies from histologically normal tracheobronchial sites from pediatric and adult donors and compared their cellular composition and gene expression profile (in laser capture-microdissected whole epithelium, fluorescence-activated cell-sorted basal cells, and basal cells in cell culture). Histologically, pediatric and adult tracheobronchial epithelium was similar in composition. We observed age-associated changes in RNA sequencing studies, including higher interferon-associated gene expression in pediatric epithelium. In cell culture, pediatric cells had higher colony formation ability, sustained in vitro growth, and outcompeted adult cells in a direct competitive proliferation assay. Our results demonstrate cell-intrinsic differences between airway epithelial cells from children and adults in both homeostatic and proliferative states.

The Impact of COVID-19 on Clinical Nurse Specialists and Patients With Cancer: A Pan-Specialty Cross-sectional Survey.

PURPOSE/AIMS: Uptake and delivery of cancer services across the United Kingdom have been significantly impacted by the COVID-19 pandemic. This study aimed to understand the impact of the pandemic on the working practices of clinical nurse specialists and their patient interactions across different cancer specialties. DESIGN: We performed a cross-sectional survey exploring nurses' experiences of delivering care during the pandemic, as well as their perceptions of the concerns that cancer patients were experiencing. METHODS: Clinical nurse specialists working in London cancer services were invited to complete an online questionnaire. Nurses' experiences and their perceptions of patients' concerns were analyzed descriptively. RESULTS: Fifty-four nurses participated. Almost half had been redeployed to other clinical areas during the pandemic (n = 19). COVID-19 discussions added 5 to 10 minutes on average to most consultations, with nurses either working longer/unpaid hours (34%) or spending less time talking to patients about cancer (39%) to deal with this. Approximately 50% of nurses would have liked additional information and support from their hospital. CONCLUSIONS: Clinical nurse specialist time and resources have been stretched during the COVID-19 pandemic. Hospitals need to work with nursing staff to ensure the specific information needs of cancer patients are being met.

Ear, nose and throat (ENT) manifestations and complications of reflux.

Laryngopharyngeal reflux disease describes the backflow of acidic stomach content towards the larynx and is associated with symptoms such as cough, throat clearing and globus. It is a common presentation in primary care and the sequelae of symptoms that arise from the disease often present in ear, nose and throat clinics. Assessment and examination of patients presenting with reflux symptoms includes questionnaires, as well as direct visualisation of the pharynx and larynx, and takes a multidisciplinary team approach. Treatment options include lifestyle modification, medical therapy and in some specialist centres, surgical management to address the multitude of symptoms associated with the disease.

Recent advances in human respiratory epithelium models for drug discovery.

The respiratory epithelium is intimately associated with the pathophysiologies of highly infectious viral contagions and chronic illnesses such as chronic obstructive pulmonary disorder, presently the third leading cause of death worldwide with a projected economic burden of £1.7 trillion by 2030. Preclinical studies of respiratory physiology have almost exclusively utilised non-humanised animal models, alongside reductionistic cell line-based models, and primary epithelial cell models cultured at an air-liquid interface (ALI). Despite their utility, these model systems have been limited by their poor correlation to the human condition. This has undermined the ability to identify novel therapeutics, evidenced by a 15% chance of success for medicinal respiratory compounds entering clinical trials in 2018. Consequently, preclinical studies require new translational efficacy models to address the problem of respiratory drug attrition. This review describes the utility of the current in vivo (rodent), ex vivo (isolated perfused lungs and precision cut lung slices), two-dimensional in vitro cell-line (A549, BEAS-2B, Calu-3) and three-dimensional in vitro ALI (gold-standard and co-culture) and organoid respiratory epithelium models. The limitations to the application of these model systems in drug discovery research are discussed, in addition to perspectives of the future innovations required to facilitate the next generation of human-relevant respiratory models.

Prediction of larynx function using multichannel surface EMG classification.

Total laryngectomy (TL) affects critical functions such as swallowing, coughing and speaking. An artificial, bio-engineered larynx (ABL), operated via myoelectric signals, may improve quality of life for TL patients. To evaluate the efficacy of using surface electromyography (sEMG) as a control signal to predict instances of swallowing, coughing and speaking, sEMG was recorded from submental, intercostal and diaphragm muscles. The cohort included TL and control participants. Swallowing, coughing, speaking and movement actions were recorded, and a range of classifiers were investigated for prediction of these actions. Our algorithm achieved F1-scores of 76.0 ± 4.4 % (swallows), 93.8 ± 2.8 % (coughs) and 70.5 ± 5.4 % (speech) for controls, and 67.7 ± 4.4 % (swallows), 71.0 ± 9.1 % (coughs) and 78.0 ± 3.8 % (speech) for TLs, using a random forest (RF) classifier. 75.1 ± 6.9 % of swallows were detected within 500 ms of onset in the controls, and 63.1 ± 6.1 % in TLs. sEMG can be used to predict critical larynx movements, although a viable ABL requires improvements. Results are particularly encouraging as they encompass a TL cohort. An ABL could alleviate many challenges faced by laryngectomees. This study represents a promising step toward realising such a device.

Throat and voice problems in Ehlers-Danlos syndromes and hypermobility spectrum disorders.

A small number of case reports and observational studies describe chronic nasal congestion, upper airway obstruction, dysphonia, vocal cord abnormalities, and swallowing abnormalities in the Ehlers-Danlos syndromes. Little is known of the causes and therefore treatments of these, yet they are not uncommon findings in persons with hypermobility-related conditions presenting in the healthcare setting. We have a specialist multidisciplinary ear, nose, and throat and speech therapy practice with accumulating observational and empirical experience of managing these conditions, which include altered voice, choking, high dysphagia and anterior and deep neck pains. Here, we present our experience, some illustrative cases, and suggestions for future work in this evolving field.

An Assistive Coughing Device for Post-Laryngectomy Patients.

People who have undergone total laryngectomy typically have difficulties speaking and coughing. Coughing, the protective reflex action where air is rapidly expelled from the lungs to clear the airway, is crucial in everyday life. Insufficiency in coughing can lead to serious chest infections. In this research we present a bionic assistive coughing device (RoboCough) to improve coughing efficacy among laryngectomy patients by increasing pressure and flow rate. RoboCough was designed to mimic the function of the glottis and trachea in the upper respiratory system. Experimental results show a significant increase (t(64) = 4.9, p < 0.0001) in peak cough flow rate and peak cough pressure (t(64) = 12.6, p < 0.0001) among 33 control participants using RoboCough. A pilot study with a smaller cohort of laryngectomy patients shows improvement in peak cough pressure (p = 0.0159) using RoboCough. Preliminary results also show that post-laryngectomy coughs achieved similar peak cough flow (Z = -0.9933, p = 0.32) to the control group's natural cough. Coughing capabilities could be improved through using RoboCough. Applications of RoboCough include simulation of vocal folds and respiratory conditions, rehabilitation of ineffective coughs from laryngeal and respiratory diseases and as a test-bed for the development of medical devices for respiratory support.

'Overnight, things changed. Suddenly, we were in it': a qualitative study exploring how surgical teams mitigated risks of COVID-19.

OBJECTIVES: COVID-19 presents a risk of infection and transmission for operating theatre teams. Guidelines to protect patients and staff emerged and changed rapidly based on expert opinion and limited evidence. This paper presents the experiences and innovations developed by international surgical teams during the early stages of the pandemic to attempt to mitigate risk. DESIGN: In-depth, semistructured interviews were audio recorded, transcribed and analysed thematically using methods of constant comparison. PARTICIPANTS: 43 participants, including surgeons from a range of specialties (primarily general surgery, otolaryngology, neurosurgery, cardiothoracic and ophthalmology), anaesthetists and those in nursing roles. SETTING: The UK, Italy, Spain, the USA, China and New Zealand between March and May 2020. RESULTS: Surgical teams sought to mitigate COVID-19 risks by modifying their current practice with an abundance of strategies and innovations. Communication and teamwork played an integral role in how teams adapted, although participants reflected on the challenges of having to improvise in real time. Uncertainties remained about optimal surgical practice and there were significant tensions where teams were forced to balance what was best for patients while contemplating their own safety. CONCLUSIONS: The perceptions of risks during a pandemic such as COVID-19 can be complex and context dependent. Management of these risks in surgery must be driven by evidence-based practice resulting from a pragmatic and novel approach to collation of global evidence. The context of surgery has changed dramatically, and surgical teams have developed a plethora of innovations. There is an urgent need for high-quality evidence to inform surgical practice that optimises the safety of both patients and healthcare professionals as the COVID-19 pandemic unfolds.

GMP compliant isolation of mucosal epithelial cells and fibroblasts from biopsy samples for clinical tissue engineering.

Engineered epithelial cell sheets for clinical replacement of non-functional upper aerodigestive tract mucosa are regulated as medicinal products and should be manufactured to the standards of good manufacturing practice (GMP). The current gold standard for growth of epithelial cells for research utilises growth arrested murine 3T3 J2 feeder layers, which are not available for use as a GMP compliant raw material. Using porcine mucosal tissue, we demonstrate a new method for obtaining and growing non-keratinised squamous epithelial cells and fibroblast cells from a single biopsy, replacing the 3T3 J2 with a growth arrested primary fibroblast feeder layer and using pooled Human Platelet lysate (HPL) as the media serum supplement to replace foetal bovine serum (FBS). The initial isolation of the cells was semi-automated using an Octodissociator and the resultant cell suspension cryopreservation for future use. When compared to the gold standard of 3T3 J2 and FBS containing medium there was no reduction in growth, viability, stem cell population or ability to differentiate to mature epithelial cells. Furthermore, this method was replicated with Human buccal tissue, providing cells of sufficient quality and number to create a tissue engineered sheet.

α-Helical peptides on plasma-treated polymers promote ciliation of airway epithelial cells.

Airway respiratory epithelium forms a physical barrier through intercellular tight junctions, which prevents debris from passing through to the internal environment while ciliated epithelial cells expel particulate-trapping mucus up the airway. Polymeric solutions to loss of airway structure and integrity have been unable to fully restore functional epithelium. We hypothesised that plasma treatment of polymers would permit adsorption of α-helical peptides and that this would promote functional differentiation of airway epithelial cells. Five candidate plasma compositions are compared; Air, N2, H2, H2:N2 and Air:N2. X-ray photoelectron spectroscopy shows changes in at% N and C 1s peaks after plasma treatment while electron microscopy indicates successful adsorption of hydrogelating self-assembling fibres (hSAF) on all samples. Subsequently, adsorbed hSAFs support human nasal epithelial cell attachment and proliferation and induce differentiation at an air-liquid interface. Transepithelial measurements show that the cells form tight junctions and produce cilia beating at the normal expected frequency of 10-11 Hz after 28 days in culture. The synthetic peptide system described in this study offers potential superiority as an epithelial regeneration substrate over present "gold-standard" materials, such as collagen, as they are controllable and can be chemically functionalised to support a variety of in vivo environments. Using the hSAF peptides described here in combination with plasma-treated polymeric surfaces could offer a way of improving the functionality and integration of implantable polymers for aerodigestive tract reconstruction and regeneration.

Modeling Normal and Pathological Ear Cartilage in vitro Using Somatic Stem Cells in Three-Dimensional Culture.

Microtia (underdeveloped ear) is a rare congenital dysmorphology affecting the development of the outer ear. Although human microtic cartilage has not been fully characterized, chondrogenic cells derived from this tissue have been proposed as a suitable source for autologous auricular reconstruction. The aim of this study was to further characterize native microtic cartilage and investigate the properties of cartilage stem/progenitor cells (CSPCs) derived from it. Two-dimensional (2D) systems are most commonly used to assess the chondrogenic potential of somatic stem cells in vitro, but limit cell interactions and differentiation. Hence here we investigated the behavior of microtic CSPCs in three-dimensional spheroid cultures. Remarkable similarities between human microtic cartilages from five patients, as compared to normal cartilage, were observed notwithstanding possibly different etiologies of the disease. Native microtic cartilage displayed poorly defined perichondrium and hyper-cellularity, an immature phenotype that resembled that of the normal developing human auricular cartilage we studied in parallel. Crucially, our analysis of microtic ears revealed for the first time that, unlike normal cartilage, microtic cartilages are vascularized. Importantly, CSPCs isolated from human microtic and normal ear cartilages were found to recapitulate many characteristics of pathological and healthy tissues, respectively, when allowed to differentiate as spheroids, but not in monolayer cultures. Noteworthily, starting from initially homogeneous cell pellets, CSPC spheroids spontaneously underwent a maturation process in culture, and formed two regions (inner and outer region) separated by a boundary, with distinct cell types that differed in chondrogenic commitment as indicated by expression of chondrogenic markers. Compared to normal ear-derived spheroids, microtic spheroids were asymmetric, hyper-cellularized and the inner and outer regions did not develop properly. Hence, their organization resembled that of native microtic cartilage. Together, our results identify novel features of microtic ears and highlight the importance of 3D self-organizing in vitro systems for better understanding somatic stem cell behavior and disease modeling. Our observations of ear-derived chondrogenic stem cell behavior have implications for choice of cells for tissue engineered reconstructive purposes and for modeling the etiopathogenesis of microtia.

Appearance and management of COVID-19 laryngo-tracheitis: two case reports.

We present two cases of coronavirus disease 2019 (COVID-19)-related laryngotracheitis in good-prognosis, ventilated patients who had failed extubation. As the pandemic continues to unfold across the globe and better management of those with respiratory failure develops, this may be an increasingly common scenario. Close ENT-intensivist liaison, meticulous team preparation, early consideration of rigid endoscopy and prospective data collection and case sharing are recommended.

Human airway-like multilayered tissue on 3D-TIPS printed thermoresponsive elastomer/collagen hybrid scaffolds.

Developing a biologically representative complex tissue of the respiratory airway is challenging, however, beneficial for treatment of respiratory diseases, a common medical condition representing a leading cause of death in the world. This in vitro study reports a successful development of synthetic human tracheobronchial epithelium based on interpenetrated hierarchical networks composed of a reversely 3D printed porous structure of a thermoresponsive stiffness-softening elastomer nanohybrid impregnated with collagen nanofibrous hydrogel. Human bronchial epithelial cells (hBEpiCs) were able to attach and grow into an epithelial monolayer on the hybrid scaffolds co-cultured with either human bronchial fibroblasts (hBFs) or human bone-marrow derived mesenchymal stem cells (hBM-MSCs), with substantial enhancement of mucin expression, ciliation, well-constructed intercellular tight junctions and adherens junctions. The multi-layered co-culture 3D scaffolds consisting of a top monolayer of differentiated epithelium, with either hBFs or hBM-MSCs proliferating within the hyperelastic nanohybrid scaffold underneath, created a tissue analogue of the upper respiratory tract, validating these 3D printed guided scaffolds as a platform to support co-culture and cellular organization. In particular, hBM-MSCs in the co-culture system promoted an overall matured physiological tissue analogue of the respiratory system, a promising synthetic tissue for drug discovery, tracheal repair and reconstruction. STATEMENT OF SIGNIFICANCE: Respiratory diseases are a common medical condition and represent a leading cause of death in the world. However, the epithelium is one of the most challenging tissues to culture in vitro, and suitable tracheobronchial models, physiologically representative of the innate airway, remain largely elusive. This study presents, for the first time, a systematic approach for the development of functional multilayered epithelial synthetic tissue in vitro via co-culture on a 3D-printed thermoresponsive elastomer interpenetrated with a collagen hydrogel network. The viscoelastic nature of the scaffold with stiffness softening at body temperature provide a promising matrix for soft tissue engineering. The results presented here provide new insights about the epithelium at different surfaces and interfaces of co-culture, and pave the way to offer a customizable reproducible technology to generate physiologically relevant 3D biomimetic systems to advance our understanding of airway tissue regeneration.

Bioengineered airway epithelial grafts with mucociliary function based on collagen IV- and laminin-containing extracellular matrix scaffolds.

Current methods to replace damaged upper airway epithelium with exogenous cells are limited. Existing strategies use grafts that lack mucociliary function, leading to infection and the retention of secretions and keratin debris. Strategies that regenerate airway epithelium with mucociliary function are clearly desirable and would enable new treatments for complex airway disease.Here, we investigated the influence of the extracellular matrix (ECM) on airway epithelial cell adherence, proliferation and mucociliary function in the context of bioengineered mucosal grafts. In vitro, primary human bronchial epithelial cells (HBECs) adhered most readily to collagen IV. Biological, biomimetic and synthetic scaffolds were compared in terms of their ECM protein content and airway epithelial cell adherence.Collagen IV and laminin were preserved on the surface of decellularised dermis and epithelial cell attachment to decellularised dermis was greater than to the biomimetic or synthetic alternatives tested. Blocking epithelial integrin α2 led to decreased adherence to collagen IV and to decellularised dermis scaffolds. At air-liquid interface (ALI), bronchial epithelial cells cultured on decellularised dermis scaffolds formed a differentiated respiratory epithelium with mucociliary function. Using in vivo chick chorioallantoic membrane (CAM), rabbit airway and immunocompromised mouse models, we showed short-term preservation of the cell layer following transplantation.Our results demonstrate the feasibility of generating HBEC grafts on clinically applicable decellularised dermis scaffolds and identify matrix proteins and integrins important for this process. The long-term survivability of pre-differentiated epithelia and the relative merits of this approach against transplanting basal cells should be assessed further in pre-clinical airway transplantation models.