Clare Selden

Background: Instructional documents are crucial for safely operating medical devices. However, few studies have explicitly considered designing instructions for health care professionals (HCPs). Psychological research suggests that advanced learners with prior expertise in a domain are better able to generalize their existing knowledge to new areas compared to those with little prior expertise, resulting in different informational needs. Objective: We aimed to understand how HCPs learn from and use their existing expertise when interacting with instructions for use to familiarize themselves with a novel medical device. This would allow us to explore how instructional documents could be designed to better accommodate HCPs’ needs as experienced learners with prior knowledge in the domain. Methods: We conducted our studies centered around a novel liver support system, the HepatiCan and its current instructions for use. We conducted 3 user studies, first using semistructured interviews and think-aloud protocols to understand HCPs’ expectations for the process of setting up the HepatiCan and how training for the use of medical devices typically takes place. We followed this up with an observational study to understand HCPs’ actual experience in practice and corresponding instructional design needs. Results: Our results showed that HCPs’ prior expertise allowed them to prioritize key areas for attention, but also led them to make assumptions and potentially skim and miss important information. Visual representations and communication were preferred, as well as designs that supported memorization, as this was an essential function of using instruction manuals. Conclusions: Developers must be aware of what is considered “common” and potentially ignored knowledge within a specific domain in order to clearly emphasize important, safety-relevant information. We also recommend developers focus on using images with attached appendices where possible. This allows advanced users to process information more efficiently without compromising the needs of less familiar users for greater instructional details.

Introduction: alternative therapies to complement liver transplantation and treat patients with liver failure are not available. In this study, a clinical scale single-use biocartridge was developed for use as part of a novel Bioartificial Liver device (HepatiCan™), utilising conditioned human-derived alginate encapsulated liver spheroids (AELS), within a fluidised bed.Methods: to develop the optimal biocartridge, two designs (B2 and B3) were created and modelled to best replicate the performance of our preexisting reusable cartridge (B1). The suitability of designs, and their ability to deliver the required hydrodynamic conditions for AELS, during both spheroid production and treatment phases, was addressed by computational fluid dynamics (CFD). Subsequently, the B3 biocartridge was produced and tested under continuous fluidisation conditions for the growth after encapsulation and recovery after cryopreservation of micro-spheroids in hydrogel scaffolds (AELS).Results: the main difference between the designs in (B2 and B3) was the base plate flow distributor. Preserving the hole pattern in the base plate, between B1 and B3, was critical for mimicking fluid flow. Additionally, increasing the number of orifices in the cross-patterned base plate design (B3) provided further benefits: maintaining homogeneity in fluid velocity distribution, whilst avoiding “dead-flow” zones. During AELS culture (using B3 format), a cell density of 24.27 ± 3.0 × 106 cells/mL of beads was achieved by day 11. Additionally, post-thaw recovery (PTR) culture of previously cryopreserved clinical doses of AELS was performed for up to 4 days. Return to the pre-freeze total biomass (6.34 ± 0.9 × 1010 cells of AELS) was achieved after 3 days of PTR; AELS growth continued to a total biomass of 8.48 ± 1.6 × 1010 cells by 4 days.Discussion: the final biocartridge design (B3) was as effective in fluid distribution as the original (B1). B3 surpassed B1 in velocity uniformity over the first 10 mm above the base plate, critical for good mass transfer between biomass and perfusing fluid in the fluidised bed. Sustained biological function for AELS after PTR was demonstrated. One remarkable advantage of this biocartridge is the recovery of functional AELS biomass after cryopreservation. Thus, we facilitate the off-the-shelf availability, whilst preserving essential biological functionality.

With the increasing interest in three-dimensional (3D) cell constructs that better represent native tissues, comes the need to also invest in devices, i.e., bioreactors, that provide a controlled dynamic environment similar to the perfusion mechanism observed in vivo. Here a laboratory-scale fluidized bed bioreactor (sFBB) was designed for hydrogel (i.e., alginate) encapsulated cells to generate a dynamic culture system that produced a homogenous milieu and host substantial biomass for long-term evolution of tissue-like structures and “per cell” performance analysis. The bioreactor design, conceptualized through scale-down empirical similarity rules, was initially validated through computational fluid dynamics analysis for the distributor capacity of homogenously dispersing the flow with an average fluid velocity of 4.596 × 10^–4 m/s. Experimental tests then demonstrated a consistent fluidization of hydrogel spheres, while maintaining shape and integrity (606.9 ± 99.3 μm diameter and 0.96 shape factor). It also induced mass transfer in and out of the hydrogel at a faster rate than static conditions. Finally, the sFBB sustained culture of alginate encapsulated hepatoblastoma cells for 12 days promoting proliferation into highly viable (>97%) cell spheroids at a high final density of 27.3 ± 0.78 million cells/mL beads. This was reproducible across multiple units set up in parallel and operating simultaneously. The sFBB prototype constitutes a simple and robust tool to generate 3D cell constructs, expandable into a multi-unit setup for simultaneous observations and for future development and biological evaluation of in vitro tissue models and their responses to different agents, increasing the complexity and speed of R&D processes.

Micro and small bioreactors are well described for use in bioprocess development in pre-production manufacture, using ultra-scale down and microfluidic methodology. However, the use of bioreactors to understand normal and pathophysiology by definition must be very different, and the constraints of the physiological environment influence such bioreactor design. This review considers the key elements necessary to enable bioreactors to address three main areas associated with biological systems. All entail recreation of the in vivo cell niche as faithfully as possible, so that they may be used to study molecular and cellular changes in normal physiology, with a view to creating tissue-engineered grafts for clinical use; understanding the pathophysiology of disease at the molecular level; defining possible therapeutic targets; and enabling appropriate pharmaceutical testing on a truly representative organoid, thus enabling better drug design, and simultaneously creating the potential to reduce the numbers of animals in research. The premise explored is that not only cellular signalling cues, but also mechano-transduction from mechanical cues, play an important role.

Liver failure, whether arising directly from acute liver failure or from decompensated chronic liver disease is an increasing problem worldwide and results in many deaths. In the UK only 10% of individuals requiring a liver transplant receive one. Thus the need for alternative treatments is paramount. A BioArtificial Liver machine could temporarily replace the functions of the liver, buying time for the patient’s liver to repair and regenerate. We have designed, implemented and tested a clinical-scale BioArtificial Liver machine containing a biomass derived from a hepatoblastoma cell-line cultured as three dimensional organoids, using a fluidised bed bioreactor, together with single-use bioprocessing equipment, with complete control of nutrient provision with feedback BioXpert recipe processes, and yielding good phenotypic liver functions. The methodology has been designed to meet specifications for GMP production, required for manufacture of advanced therapy medicinal products (ATMPs). In a porcine model of severe liver failure, damage was assured in all animals by surgical ischaemia in pigs with human sized livers (1.2–1.6 kg liver weights). The BioArtificial liver (UCLBAL) improved important prognostic clinical liver-related parameters, eg, a significant improvement in coagulation, reduction in vasopressor requirements, improvement in blood pH and in parameters of intracranial pressure (ICP) and oxygenation.

Liver failure is an increasing problem. Donor-organ shortage results in patients dying before receiving a transplant. Since the liver can regenerate, alternative therapies providing temporary liver-support are sought. A bioartificial-liver would temporarily substitute function in liver failure buying time for liver regeneration/organ-procurement. Our aim: to develop a prototype bioartificial-liver-machine (BAL) comprising a human liver-derived cell-line, cultured to phenotypic competence and deliverable in a clinical setting to sites distant from its preparation. The objective of this study was to determine whether its use would improve functional parameters of liver failure in pigs with acute liver failure, to provide proof-of-principle. HepG2cells encapsulated in alginate-beads, proliferated in a fluidised-bed-bioreactor providing a biomass of 4–6×10¹⁰cells, were transported from preparation-laboratory to point-of-use operating theatre (6000miles) under perfluorodecalin at ambient temperature. Irreversible ischaemic liver failure was induced in anaesthetised pigs, after portal-systemic-shunt, by hepatic-artery-ligation. Biochemical parameters, intracranial pressure, and functional-clotting were measured in animals connected in an extracorporeal bioartificial-liver circuit. Efficacy was demonstrated comparing outcomes between animals connected to a circuit containing alginate-encapsulated cells (Cell-bead BAL), and those connected to circuit containing alginate capsules without cells (Empty-bead BAL). Cells of the biomass met regulatory standards for sterility and provenance. All animals developed progressive liver-failure after ischaemia induction. Efficacy of BAL was demonstrated since animals connected to a functional biomass (+ cells) had significantly smaller rises in intracranial pressure, lower ammonia levels, more bilirubin conjugation, improved acidosis and clotting restoration compared to animals connected to the circuit without cells. In the +cell group, human proteins accumulated in pigs' plasma. Delivery of biomass using a short-term cold-chain enabled transport and use without loss of function over 3days. Thus, a fluidised-bed bioreactor containing alginate-encapsulated HepG2cell-spheroids improved important parameters of acute liver failure in pigs. The system can readily be up-scaled and transported to point-of-use justifying development at clinical scale.