Periodic Reporting for period 1 - SENSINGTech (Sensor-based technological platform to investigate the effect of age-induced changes of oral physiology on the bolus properties and on the subsequent phases of swallowing and digestion)
Okres sprawozdawczy: 2022-09-01 do 2024-08-31
The objectives of SENSINGTech are to:
- integrate in vitro mastication and swallowing technologies to replicate the complex dynamics of “Stage II Transport” during solid food intake
- investigate the influence of masticatory parameters, saliva addition, and its distribution on bolus properties, and their impact on subsequent swallowing and digestion phases
- provide critical insights to define clear thresholds for food characteristics that ensure safe swallowing, tailored to the severity and specific areas affected by swallowing disorders.
Key advancements include:
• Hard food processing: Using the Advanced Masticatory Machine (AM2), the role of saliva in forming a cohesive bolus from hard foods like bread was explored. In vitro simulations showed that insufficient saliva resulted in dangerously large particles, while excessive saliva overly fragmented food, highlighting the need for optimal salivary conditions.
• Soft food interaction: The Artificial Mouth model replicates tongue biomechanics to study the interaction of soft foods, such as viscous liquids, gels and mousses, with the oral cavity. Food bolus adhesion, cohesion, and viscosity were characterised, with bolus formation validated against human data.
• 3D Biomimetic Soft Robotic Masticator:The SRM, a first-of-its-kind device, replicates chewing and food oral transport with unmatched realism. In vitro findings closely aligned with in vivo observations, although salivary substitutes fell short of fully mimicking natural saliva intricate roles.
This research underscores the pivotal role of saliva in oral food processing, with solid foods requiring coordinated tongue-teeth movements for ready-to-swallow bolus formation, while soft foods depend on tongue shear and mixing to achieve proper viscosity and textural properties. These studies mark a major step forward in personalised food design and advancing healthy ageing.
The studies conducted have explored the role of saliva in the bolus formation of a hard and dry food such as bread, particularly in how its characteristics — such as quantity, composition, temperature, and enzymatic activity — affect particle size and cohesion. Using the Advanced Masticatory Machine (AM2), we have simulated various salivary conditions, ranging from xerostomia to hypersalivation. Results demonstrated that the absence of saliva leads to boli with dangerously large particles, while excessive saliva can overly break down food.
As a part of SENSINGTech, a biomimetic model, the Artificial Mouth, simulating tongue biomechanics during the oral processing of soft foods was developed, focusing on the interaction of food with the tongue and palate. We characterised foods with complex textures, such as gels and mousses, by evaluating their adhesive, cohesive, and viscosity properties. Bolus formation was analysed under in vitro conditions, and the results were validated against in vivo data.
Finally, a first-of-its-kind 3D biomimetic soft robotic masticator (SRM) was introduced, being capable of replicating intraoral events with unmatched realism, including food transport and chewing. The findings showed a close correlation between the properties of boli formed in vitro and those formed in vivo. Although the use of a salivary substitute provides some benefits, such as enhanced lubrication and reduced viscosity, under the studied conditions, it cannot fully replicate the intricate interactions and functions of natural saliva.
Overall, the combined findings emphasise the critical role of saliva in regulating hydration, cohesion, and physical and chemical breakdown, as well as its varying impact on solid and soft foods. For swallowing, solid foods require coordinated movements of the tongue, teeth, and saliva to achieve proper optimal bolus properties, while for soft foods depend on tongue shear and mixing.