Synthesis of Long Afterglow Photoluminescent Materials Sr_2MgSi_2O_7∶Eu^(2+), Dy^(3+) by Sol-Gel Method

Long afterglow photoluminescent materials Sr2MgSi2O7 doped with Eu2+, Dy3+ were prepared by sol-gel method. The synthesized samples were characterized by X-ray diffraction. The excitation spectrum, emission spectrum and long decay curve were measured and analyzed. XRD pattern indicates that phosphor is with Sr2MgSi2O7 crystal structure. The wide range of excitation wavelength indicates that luminescent material can be excited by light from ultraviolet ray to visible light. The main peak of emission spectrum is located at 466 nm. Sample excited by visible light can emit bright blue light, and the afterglow time lasts more than 8 h.

Luminescence properties of a single-host phosphor Ba_(1.8-w)Sr_wLi_(0.4)SiO_4:Ce^(3+),Eu^(2+),Mn^(2+) for WLED

In order to obtain a single-host-white-light phosphor, a series of Bal.8 -x-y-zSrwLi0.4xCexEuyMnzSi04 （BSLS：Ce3＋,Eu2＋, Mn2＋） powder samples were synthesized via high temperature solid-state reaction. The structure and photoluminescence properties were investigated. Under ultraviolet excitation, the emission spectra contained three bands： the 370-470 nm blue band, the 470-570 nm green band and the 570-700 nm red band, which arose from the 5d---4f transitions of Ce3＋ and Eu2＋, and the 4TI---6A1 transition of Mn2＋, respectively. The excitation spectra of the emissions of Ce3＋ and Mn2＋ ions showed the energy transfer from Ce3＋ to Mn2＋. White light emission was obtained from the tri-doped samples of appropriate doping concentration under 31 0-360 nm excitation.

A biomaterial-based therapy for lower limb ischemia using Sr/Si bioactive hydrogel that inhibits skeletal muscle necrosis and enhances angiogenesis

Muscle necrosis and angiogenesis are two major challenges in the treatment of lower-limb ischemic diseases.In this study,a triple-functional Sr/Si-containing bioceramic/alginate composite hydrogel with simultaneous bioactivity in enhancing angiogenesis,regulating inflammation,and inhibiting muscle necrosis was designed to treat lower-limb ischemic diseases.In particular,sodium alginate,calcium silicate and strontium carbonate were used to prepare injectable hydrogels,which was gelled within 10 min.More importantly,this composite hydrogel sustainedly releases bioactive Sr^(2+)and SiO_(3)^(2-) ions within 28 days.The biological activity of the bioactive ions released from the hydrogels was verified on HUVECs,SMCs,C2C12 and Raw 264.7 cells in vitro,and the therapeutic effect of the hydrogel was confirmed using C57BL/6 mouse model of femoral artery ligation in vivo.The results showed that the composite hydrogel stimulated angiogenesis,developed new collateral capillaries,and re-established the blood supply.In addition,the bioactive hydrogel directly promoted the expression of muscle-regulating factors(MyoG and MyoD)to protect skeletal muscle from necrosis,inhibited M1 polarization,and promoted M2 polarization of macrophages to reduce inflammation,thereby protecting skeletal muscle cells and indirectly promoting vascularization.Our results indicate that these bioceramic/alginate composite bioactive hydrogels are effective biomaterials for treating hindlimb ischemia and suggest that biomaterial-based approaches may have remarkable potential in treating ischemic diseases.