Rapid progress in biological sensing and imaging technologies offers new and exciting opportunities to identify biochemical changes fundamental to preclinical research that may develop into the next generation of point‐of‐care devices. Small upconverting fluorescent nanoparticles (UCNPs) are a special class of lanthanide‐doped, optically active, microscopic particles that fluoresce upon near‐infrared light activation. With the additional advantages of deep penetration, minimal photodamage, and low background fluorescence in biological tissues, biosensors incorporating these lanthanide nanoparticles are rapidly emerging as serious contenders to rival the traditional downconversion‐based fluorescence nanoparticles. Emphasizing on two application areas, namely biosensing and bioimaging, the recent developments in lanthanide‐based UCNP design for optimum upconversion efficiency are reviewed. The article discusses the use of UCNPs in biosensing and bioimaging, highlights the challenges that hamper further applications, and concludes with future directions.

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Periodontal regeneration plays an integral role in the treatment of periodontal diseases, with important clinical significance for the preservation and functional recovery of affected teeth. Periodontal ligament stem cells (PDLSCs), which were found in the periodontal ligament tissues possessing properties of pluripotency and self-renewing, could repair damaged periodontium with great promise. However, in a chronic inflammatory micro-environment, these cells suffered from reduced capacity to differentiate and regenerate. There has been a growing appreciation that tumour necrosis factor-α (TNF-α) in periodontal tissues drives cellular responses to chronic periodontitis. Several new advances, including an increased understanding of the mechanism of interaction between TNF-α and PDLSCs provides insight into inflamed cell regeneration, which in turn reveal strategies to improve the effectiveness of therapy. Here we gave a comprehensive review on the role of TNF-α in chronic periodontitis, its effect on PDLSCs differentiation and periodontal regeneration, related signaling pathways and concluded with future perspectives of research on PDLSCs-based periodontal tissue regeneration.

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Engineering highly sensitive nanomaterials to monitor spatiotemporal pH changes has rather broad applications in studying various biological systems. Intraoral/biofilm−tooth pH is the single parameter that has demonstrated accurate assessment of dental caries risk, reflecting the summative integrated outcome of the complicated interactions between three etiological factors, namely, microorganisms/biofilm, diet/carbohydrates, and tooth/saliva/host. However, there is little to no technology/system capable of accurately probing simultaneously both the micro-pH profiles in dentin tissues and acidogenic oral biofilms and examining the pathophysiologic acid attacks with high spatial/temporal resolution. Therefore, a highly sensitive pH-responsive hybrid nanoparticle (pH-NP) is developed and coupled with an ex vivo tooth−biofilm caries model to simulate and study the key cariogenic determinants/steps. The pH-NP emits two distinct fluorescences with mutually inversely proportional intensities that vary accordingly to the proximity pH and with a ratiometric output sensitivity of 13.4-fold across a broad clinically relevant pH range of 3.0−8.0. Using [H + ], in addition to pH, to calculate the "area-under-curve" corroborates the "minimum-pH" in semiquantifying the demineralizing potential in each biofilm-dentin zones/depth. The data mechanistically elucidates a two-pronged cariogenic effect of a popularacidic-sweet-drink, in inundating the biofilm/tooth-system with H + ions from both the drink and the metabolic byproducts of the biofilm.