Dental caries is the breakdown of the hard dental tissues by the acid produced by bacteria in the mouth. It is recognised that many children and adults suffer unnecessary pain due to the destruction of the tooth and infection of the pulp (nerve). If not treated, then the tooth needs to ultimately be extracted. This non-communicable disease is entirely preventable. Eliminating the established oral biofilm that houses the bacteria that start this destructive process is however a challenge. Once bacteria break through the enamel of the tooth their passage to the pulp of the tooth is helped by the structure of dentine. This hard, dental tissue contains numerous microchannels (dentine tubules), which communicate from the external surface of the tooth to the internal pulp. The biofilm may be prevented by diet and use of fluoride toothpastes but once established is difficult to eradicate. Antibiotics are not very effective as there is no blood supply that enables them to reach the infected area and are therefore misused in the treatment of dental infections. A local treatment is proposed that allows for the rapid release of antibacterial agents at the site of infection. In this research programme we aim to rapidly tackle biofilm infections with an interdisciplinary approach based on a novel particle platform for localised drug-delivery using ultrasound as an external-physical stimulus to trigger the release of an encapsulated antibacterial agent from inside the particles. We have assembled a multidisciplinary team with expertise in chemistry, dentistry and fluid mechanics to study the ultrasound triggered activation and delivery of the silica particles in endodontic model structures, biofilms and explanted teeth. To this end we will use existing dental instruments such as ultrasonic scalers in kHz frequencies which are commonly used in dental clinics. We will employ unique flow characterisation approaches to clarify the effects of ultrasound on particle motion, directing the particles to the biofilm, and on agent release. We have chosen to work with silica particles due to their biocompatibility and the wide applicability of silica materials in dentistry. We will use particle designs to control the entrapment of the antibacterial agent which can only be released upon application of the ultrasound trigger. The particles will be developed with luminescent properties to allow optical detection of their motion in flow and to monitor the antibacterial agent release in solution. We aim to tackle problems in dental healthcare and to accelerate particle based therapies in dental practice through our impact activities. The proposed research will also provide revolutionary ways for antibiotic delivery in other areas of healthcare where localized treatment of infection is challenging (prosthetics, catheters).

We propose a Centre-to-Centre consortium formed of 10 academics from the University of Sheffield (USHEF) and the Technical University of Dortmund (TUD) to exploit light-matter interactions in advanced materials, achieving agenda-setting advances in non-linear optics, single photon phenomena and spin-control on the nanoscale. We will study ultra-pure cuprous oxide, atomically thin two-dimensional semiconductors, and III-V semiconductor nano-structures, all at the forefront of modern day research. The collaboration provides major added value to the UK by enabling cutting-edge research themes supported by close interaction with highest quality scientists at TUD, as well as access to their world-leading experimental infrastructure. The interaction of light and matter is at the heart of a huge range of natural phenomena and applications in physics, chemistry, biology etc. In this project, we will use potentially transformative approaches to harnessing these phenomena by using specially designed nano-structured materials, and exploring non-linear and quantum optical phenomena in micro- and nano-photonic structures. The ambition is to seed and develop new research directions based on enhancing and controlling light-matter interactions in nanoscale structures. To this end we will use a broad base of novel materials including atomically thin layers of transition metal dichalcogenides (TMDs), ultra-pure Cu2O, and quantum dots located within III-V semiconductor nano-photonic structures. The consortium will address three inter-related themes having considerable synergy and sharing of techniques and physics including: non-linear and quantum optics with Rydberg exciton-polaritons in cuprous oxide; valley phenomena in van der Waals heterostructures; ultrafast quantum nano-photonics. All three themes involve the harnessing of light-matter interactions in novel material systems. Design on the nanoscale is a common theme throughout enabling the discovery of new optical and quantum-optical phenomena. Furthermore, they all rely on the control of the properties of excitons in extreme limits. As well as leading to ground-breaking new physics, the programme has potential to open up long term applications in quantum communications and in spintronic devices to give just two examples. The highly integrated collaboration programme, exploiting to the full the benefits of the Centre-to-Centre cooperation, will be supported by a total of 60 months of extended visits by postdocs in both directions between Sheffield and Dortmund.