Objectives. Enamel erosion caused by high consumption of acidic drinks poses a significant public health concern. This study was aimed to determine the protective effect of eggshell-titanium dioxide composite (EB@TiO₂) against erosive acids on tooth enamel. Methods. Twenty prepared bovine tooth enamel specimens were randomly assigned to 5 sample groups (n=4): (1) unexposed tooth enamel; (2) exposed tooth enamel + HCI; (3) exposed tooth enamel + HCI + Colgate toothpaste; (4) exposed tooth enamel + HCI + Sensodyne toothpaste; and (5) exposed tooth enamel + HCI + EB@TiO₂. The mean roughness value (R_rms) of the exposed and unexposed tooth was measured with atomic force microscope (AFM). Scanning electron microscope (SEM) and Raman spectroscopy techniques were used to evaluate the surface morphology and changes. ANOVA was used to analyze the mean square roughness (R_rms) values for all specimens. Bonferonni correction was used to identify the mean differences among the 5 groups (α=0.05). The R_rms values measured for the unexposed and exposed specimens in HCI alone were statistically significant (P<0.05). Results. No significant differences were found for the unexposed and exposed specimens in HCI + toothpaste and EB@TiO₂. The tooth enamel specimens exposed to HCI + Sensodyne had the highest R_rms values, while specimens exposed to HCI + EB@TiO₂ had the lowest R_rms values. Conclusions. This study confirms that the investigated toothpaste provides protection against acidic substances. The study results further suggests that EB@TiO₂ could be used to provide enhanced protection for tooth enamel.

[This corrects the article DOI: 10.1155/2018/4216415.].

In vivo cellular imaging and in vitro assays or sensors are fundamentally used to study the spatiotemporal interaction of molecules at biological interfaces. The study of these interfaces informs various applications such as diagnostics/detection of foreign materials or processes in the biological system. Raman spectroscopy, an optical, non-destructive, label-free fingerprinting tool offers a wide array of applications in both in vitro and in vivo diagnostics owing to its relatively short acquisition time, non-invasiveness and ability to provide biochemical molecular information. It has been explored in tissue imaging, in vitro diagnosis, DNA/RNA analysis, metabolic accretions, single cell analysis photodynamic therapy, etc. The chapter details the application of the optical Raman platform in the detection and imaging of diseases/tissues. The challenges associated with SERS applications and the future outlook as a biomedical diagnostic tool are also discussed.

The recent global pandemic caused by Covid-19 enforced the urgent need for accessible, reliable, and accurate point-of-care rapid diagnostics based on plasmonic nanostructures. This is because fast and reliable testing was the key driver in curbing the spread of Covid-19. The traditional methods of diagnostics and biosensors often require expensive infrastructure and highly qualified and trained personnel, which limits their accessibility. These limitations perpetuated the impact of Covid-19 in most countries because of the lack of easily accessible point-of-care rapid diagnostic kits. This review revealed that portable and reliable point-of-care diagnostic kits are very crucial in reaching large populations, especially in underdeveloped and developing countries. This gives perspective to novel point-of-care applications. Furthermore, water quality is a very crucial part of food safety, especially in developing countries faced with water contamination. In this chapter, we explored the various challenges and recent developments in the use of plasmonic nanostructures for application in molecular diagnostics and biosensing for the detection of infectious diseases and common environmental pathogens.

Plasmonic gold nanoparticles significantly improved the efficiency of a TiO₂ and Eosin Y based dye-sensitized solar cell from 2.4 to 6.43%. The gold nanoparticles’ sizes that were tested were 14 nm, 30 nm and 40 nm synthesized via the systematic reduction of citrate concentration using the Turkevich method. Prestine TiO₂ without plasmonic gold nanoparticles yielded an efficiency of 2.4%. However, the loading of 40 nm gold nanoparticles into the TiO₂ matrix yielded the highest DSSC efficiency of 6.43% compared to 30 nm (5.91%) and 14 nm (2.6%). The relatively high efficiency demonstrated by plasmonic gold nanoparticles is ascribed to light absorption/scattering, hot electron injection and plasmon-induced resonance energy transfer (PIRET), influenced by the size of the gold nanoparticles.