Fabrication of astaxanthin-loaded electrospun nanofiber-based mucoadhesive patches with water‐insoluble backing for the treatment of oral premalignant lesions

Oral premalignant lesions (OPL) are one of the most common oral diseases, affecting the quality of life and even leading to oral cancer. Current treatments commonly use steroids/retinoids in mouthwashes, films, or ointments. However, conventional drugs/formulations have significant side effects/limitations. Herein, astaxanthin-loaded polycaprolactone (PCL)/gelatin (GT) nanofiber-based mucoadhesive patches (PGA) with the water‐insoluble PCL nanofiber backing (PCL/PGA) are developed via electrospinning for the management of OPL. The saliva-insoluble PCL backing could greatly prevent drug loss after application in the oral cavity. The prepared PCL/PGA patches exhibit a suitable astaxanthin release rate for achieving high local drug concentration, which permeated into buccal mucosa. In addition, the developed thin patches display excellent wet tissue adhesion and great air permeability due to their high porosity. Notably, the in vivo experiment shows that the bioactive mucoadhesive patches significantly promote the recovery of OPL by suppressing the expression of Ki67 and cyclooxygenase-2 (COX-2), comparable to clinical tretinoin cream formulation. Also, the patches did not induce any side effects (i.e., hair loss and oral ulcers) compared to clinical tretinoin cream formulation. The results demonstrate that this novel electrospun mucoadhesive bilayer patch holds great potential for the treatment of OPL

SDF-1 promotes endochondral bone repair during fracture healing at the traumatic brain injury condition.

The objective of this study was to investigate the role of stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, on bone healing and whether SDF-1 contributes to accelerating bone repair in traumatic brain injury (TBI)/fracture model.Real-time polymerase chain reaction and immunohistochemical analysis were used to detect the expression of SDF-1 during the repair of femoral bone in TBI/fracture model. The TBI/fracture model was treated with anti-SDF-1 neutralizing antibody or AMD3100, an antagonist for CXCR4, and evaluated by histomorphometry. In vitro and in vivo migration assays were used to evaluate the functional effect of SDF-1 on primary mesenchymal stem cells.The expression of SDF1 and CXCR4 messenger RNA was increased during the bone healing in TBI/fracture model but was less increased in fracture only model. High expression of SDF-1 protein was observed in the surrounding tissue of the damaged bone. Treated with anti-SDF-1 antibody or AMD3100 could inhibit new bone formation. SDF-1 increased mesenchymal stem cell chemotaxis in vitro in a dose-dependent manner. The in vivo migration study demonstrated that mesenchymal stem cells recruited by SDF-1 participate in endochondral bone repair.The SDF-1/CXCR4 axis plays a crucial role in the accelerating fracture healing under the condition of TBI and contributes to endochondral bone repair

Ultrasensitive Frequency Shifting of Dielectric Mie Resonance near Metallic Substrate

Dielectric resonators on metallic surface can enhance far-field scattering and boost near-field response having promising applications in nonlinear optics and reflection-type devices. However, the dependence of gap size between dielectric resonator and metallic surface on Mie resonant frequency is complex and desires a comprehensive physical interpretation. Here, we systematically study the effect of metallic substrate on the magnetic dipole (MD) resonant frequency at X-band by placing a high permittivity CaTiO3 ceramic block on metallic substrate and regulating their gap size. The simulated and experimental results show that there are two physical mechanisms to codetermine the metallic substrate-induced MD frequency. The greatly enhanced electric field pair in the gap and the coupling of MD resonance with its mirror image are decisive for small and large gaps, respectively, making the MD resonant frequency present an exponential blue shift first and then a slight red shift with increasing gap size. Further, we use the two mechanisms to explain different frequency shifting properties of ceramic sphere near metallic substrate. Finally, taking advantage of the sharp frequency shifting to small gaps, the ceramic block is demonstrated to accurately estimate the thickness or permittivity of thin film on metallic substrate through a governing equation derived from the method of symbolic regression. We believe that our study will help to understand the resonant frequency shifting for dielectric particle near metallic substrate and give some prototypes of ultrasensitive detectors

Electrospun Nanofibers Containing Strontium for Bone Tissue Engineering

Electrospun polymer/metal composite nanofibers have received much attention in the field of bone tissue engineering and regenerative medicine (BTERM) owing to their extracellular matrix- (ECM-) like structure, sufficient mechanical strength, favorable biological properties, and bone induction. In particular, electrospun nanofibers containing strontium (Sr) can significantly promote bone repair and regeneration by mediating osteolysis and osteogenesis, which offers a promising bioactive material for BTERM. In this review, we summarized the effects of electrospun nanofibers containing Sr on stem cells, osteoblasts, and osteoclasts in BTERM. Also, current challenges and future perspectives for electrospun nanofibers containing Sr in BTERM are briefly outlined. It is hoped that the systematic overview will inspire the readers to further study Sr-containing nanofibers for BTERM and accelerate their translation from the bench to the clinic

Effects of SDF-1 on stem cell recruitment in vivo and in vitro.

<p>Effects of SDF-1 on stem cell recruitment in vivo and in vitro.</p