Objective:To prepare a drug release system of drug-loaded cross-linked decellularized corneal stromal lenticules and evaluate its drug release characteristics in vitro. Methods:Lenticules were obtained during femtosecond laser-assisted small incision lenticule extraction (SMILE) surgery in Chongqing Aier Ophthalmology Hospital.Decellularized corneal stromal lenticules were prepared using high concentration sodium chloride (NaCl) combining nuclease.The decellularized corneal stromal lenticules were randomly divided into normal group, 0.5% levofloxacin group, 3% levofloxacin group and 5% levofloxacin group, with 4 lenticules in each group.The lenticules did not receive any treatment in the normal group, and drug-loading those were soaked in different doses of levofloxacin solution for three hours according to grouping.In the crosslinking test, 12 decellularized corneal stromal lenticules were randomly divided into non-crosslinking group, 0.01 mmol 1-(3-dimethylamino) propylimine (EDC) group, 0.05 mmol EDC group and 0.25 mmol EDC group.The lenticules for cross-linking were soaked in different contents of mixed solution of EDC with N-hydroxysuccinyl (NHS) for four hours respectively according to grouping, and then in 3% levofloxacin solution for three hours.Only 3% levofloxacin solution soaking was carried in the non-crosslinking group.High performance liquid chromatography (HPLC) was employed to detect the drug release concentration of the lenticules, and spectral scanning method was performed to measure light transittance of the lenticules.The surface ultrastructure of the decellularized lenticules among different cross-linking groups was examined and compared with scanning electron microscope.The use of the human corneal lenticules was approved by an Ethics Committee of Chongqing Aier Ophthalmology Hospital (No.2019012). Written informed consent was obtained from each patient before surgery.Results:The release concentrations of decellularized corneal stroma lenticules were significantly different at 1 day, 7, 14, and 21 days among 0.5%, 3%, and 5% levofloxacin group ( P<0.05) or also among the 0.01 mmol EDC, 0.05 mmol EDC, and 0.25 mmol EDC cross-linked groups ( P<0.01). The drug release concentrations in 0.05 mmol EDC group were the highest at various time points, and the release time of the three cross-linked groups lasted until 21 days after release concentrations of decellularized corneal stroma lenticules.The drug release concentrations in cross-linked groups and non-crosslinking group were gradually declined with the prolong of drug-loading time, showing a significant difference at different time points ( P<0.05). The transmittance of the lenticules was (88.68±1.19)% and (91.55±1.16)% in the non-crosslinking group and normal group, respectively, with no significant difference ( P>0.05). The average transmittance of the lenticules was significantly reduced in the drug-loaded groups compared with the normal group ( P<0.05). The smaller collagen fiber voids and closely arranged collagen fibers were displayed in the cross-linking groups under the scanning electron microscope with the best effect in the 0.25 mmol EDC group. Conclusions:EDC/NHS cross-linking can improve the drug-loading effect of decellularized corneal stromal lenticules probably by lessening collagen fiber voids.The drug-loaded cross-linked decellularized corneal stromal lenticules have a good drug release effect in vitro.

Objective:To explore the application value of scenario simulation teaching combined with two-way evaluation in standardized training of pediatric nursing.Methods:A total of 34 trainees who received standardized training of pediatric nursing in The First Affiliated Hospital of Air Force Medical University from March 2018 to March 2019 were selected as the control group, and another 42 trainees from April 2019 to July 2020 were selected as the study group. The control group used traditional teaching, and the study group used scenario simulation teaching combined with two-way evaluation. Theoretical examination and scenario simulation exercise examination were used to assess the theoretical knowledge and clinical practice ability of the trainees, and questionnaire survey was used to evaluate the satisfaction of the trainees with the teaching effect. SPSS 22.0 was used for t-test. Results:The scores of theoretical examination[(95.12±6.24) vs. (91.05±5.12)] and scenario simulation exercise examination (nursing practice skill operation ability, ability to combine theory and practice, clinical thinking and judgment ability, emergency handling ability, communication ability, humanistic care and professional learning ability, and work attitude) of the trainees in the study group were higher than those in the control group, and the differences were statistically significant ( P<0.05). The satisfaction evaluation of the trainees in the study group with the teaching effect was higher than that in the control group, and the difference was statistically significant ( P<0.001). Conclusion:Scenario simulation teaching combined with two-way evaluation can improve the theoretical knowledge, clinical practice ability, and teaching satisfaction of pediatric nursing trainees.

Adipocytes ; Adipose Tissue ; Exosomes ; Stem Cells ; Wound Healing

In the field of plastic and reconstructive surgery, the loss of organs or tissues caused by diseases or injuries has resulted in challenges, such as donor shortage and immunosuppression. In recent years, with the development of regenerative medicine, the decellularization-recellularization strategy seems to be a promising and attractive method to resolve these difficulties. The decellularized extracellular matrix contains no cells and genetic materials, while retaining the complex ultrastructure, and it can be used as a scaffold for cell seeding and subsequent transplantation, thereby promoting the regeneration of diseased or damaged tissues and organs. This review provided an overview of decellularization-recellularization technique, and mainly concentrated on the application of decellularization-recellularization technique in the field of plastic and reconstructive surgery, including the remodeling of skin, nose, ears, face, and limbs. Finally, we proposed the challenges in and the direction of future development of decellularization-recellularization technique in plastic surgery.
Tissue Engineering/methods* ; Tissue Scaffolds/chemistry* ; Surgery, Plastic ; Regenerative Medicine/methods* ; Extracellular Matrix