Acceptor-donor-acceptor-type molecules with large electrostatic potential difference for effective NIR photothermal therapy.

Although acceptor-donor-acceptor (A-D-A)-type molecules offer advantages in constructing NIR absorbing photothermal agents (PTAs) due to their strong intramolecular charge transfer and molecular planarity, their applications in photothermal therapy (PTT) of tumors remain insufficiently explored. In particular, the influence of ESP distribution on the optical properties of A-D-A photosensitizers has not been investigated. Herein, we analyze and compare the difference in ESP distribution between A-D-A-type small molecules and polymers to construct NIR absorbing PTAs with a high extinction coefficient (ε) and high photothermal conversion efficiency (PCE). The calculation results of density functional theory (DFT) indicate that the large ESP difference makes A-D-A-type small molecules superior to their polymer counterparts in realizing tight molecular packing and strong NIR absorbance. Among the as-prepared nanoparticles (NPs), Y6 NPs exhibited an obvious bathochromic shift of absorption peak from 711 nm to 822 nm, with the NIR-II emission extended to 1400 nm. Moreover, a high ε value of 5.69 L g-1 cm-1 and a PCE of 66.3% were attained, making Y6 NPs suitable for PTT. With a concentration of 100 µg mL-1, Y6 NPs in aqueous dispersion yielded a death rate of 93.4% for 4T1 cells upon 808 nm laser irradiation (1 W cm-2) for 10 min, which is comparable with the best results of recently reported PTT agents.

Effects of different custom-made mouthguard palatal extensions on the stress-state of dentoalveolar structures: a 3D-FEA.

OBJECTIVES: The present study aimed to simulate the influence of palatal extensions for custom-made mouthguards (MGs) on protecting dentoalveolar structures and to provide a theoretical basis for designing a comfortable MG. MATERIALS AND METHODS: Based on finite element analysis (3D-FEA), five groups of maxillary dentoalveolar models of wearing MGs were established: no MG on palatal side (NP), on palatal gingival margin (G0), 2 mm from the palatal gingival margin (G2), 4 mm from the palatal gingival margin (G4), 6 mm from the palatal gingival margin (G6), and 8 mm from the palatal gingival margin (G8). A cuboid was created to simulate the solid ground impacted in falls, a gradually increasing force was applied from 0 to 500 N on the vertical ground, and the distribution and peak values of the Critical modified von-Mises stress, maximum principal stress, and displacement of dentoalveolar models were calculated. RESULTS: Stress distribution range, stress, and deformation peak value of dentoalveolar models increased as the impact strength increased, at 500 N. Maximum critical modified von-Mises stress, peak maximum principal stress and maximum displacement of dentoalveolar models G4, G3, G2, G1, G0, and NP were 154.5 MPa, 154.5 MPa, 154.4 MPa, 154.7 MPa, 154.4 MPa, and 154.7 MPa; 191.65 MPa, 192.11 MPa, 191.62 MPa, 191.81 MPa, 191.56 MPa, and 191.62 MPa; and 88.78 µm, 88.57 µm, 88.19 µm, 88.67 µm, 88.43 µm, and 89.04 µ, respectively. However, the position of the MG palatal edge had little effect on stress distribution, stress, and deformation peak values of the dentoalveolar models. CONCLUSIONS: Different extension ranges of the MG palatal edge have little effect on the protective effects of MGs on maxillary teeth and maxilla. An MG with palatal extension on the gingival margin is more appropriate than other models and may help dentists to design a suitable MG and increase its usage. CLINICAL RELEVANCE: MGs with palatal extensions on the gingival margin may provide a more comfortable wearing experience for individuals involved in sports and encourage increased MG usage.