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Aim To prepare prostate cancer exosomes containing melittin and observe their uptake by prostate cancer cells. Methods Cells treated with starvation for different time were screened for exosome extraction. Exosomes from PC-3 cells were extracted by ultracentrifugation, and the extracted particles were examined by transmission electron microscopy, nanoparticle tracking analyzer(NTA), and Western blot. Melittin exosome system was prepared by repeated freeze-thaw method, incubation at room temperature as well as electroporation, and the size of encapsulation efficiency was measured by centrifugation. A high-performance liquid chromatography(HPLC)method was applied to assay the content of melittin exosomes(exo-mel). Fluorescence inverted microscopy was employed to evaluate the uptake of melittin exosomes by PC-3 cells, DU145 cells as well as LNCaP cells. Results The results of starvation treatment showed that 24 h starvation treatment was the optimal time point. TEM results showed that the exosomes were round or oval in shape with a distinct membranous structure, and the diameter was around 100 nm. The reagent protein concentration for NTA analysis of exosomes was 0.222 g·L-1. The results of Western blot for the marker proteins of exosomes showed that Alix and CD63 were positively expressed, which indicated that the exosomes could be obtained by starvation culture of PC-3 cells and ultracentrifugation. The results of entrapment efficiency showed that the entrapment efficiency of electroporation method was 17.51% ± 2.39%, that of repeated freeze-thaw method was 11.46% ± 1.02%, and that of room temperature incubation method was 3.93% ± 2.44%. The encapsulation efficiency of electroporation was the highest with significant difference(P<0.05). The uptake assay showed that PC-3 cells could efficiently take up exo-mel in a time-dependent manner, and DU145 cells and LNCaP cells also could take up exo-mel over time. Conclusions Exosomes can be accessed by starvation treatment and high-speed centrifugation, and the prostate cancer melittin exosome system prepared by electroporation method could be taken up by prostate cancer cells.
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Antimicrobial peptides (AMPs) distribute widely in many organisms. As an important part of the nonspecific immune functions of organisms, AMPs can not only protect the body from bacteria, fungi, parasites, viruses, and other pathogens, but also have the functions of mediating catalysis, apoptosis, immune regulatory activity, accelerating wound healing and osteogenetic effects. AMPs have become a research focus for antimicrobial coating on titanium implant surface and have shown a promising prospect. In this paper, we reviewed the antimicrobial mechanism, loading method, and application status of AMPs applied on titanium implant surface.
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Objective To prepare F7 thermosensitive liposome and evaluate its physicochemical properties, then investigate its cytotoxicity against tumor cells in vitro. Methods The F7 thermosensitive liposome was prepared by the pH gradient active drug loading method using dipalmitoyl phosphatidylcholine myristoyl lyso-phosphocholine and 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy (polyethylene glycol)-2000 as membrane materials. The encapsulation efficiency and drug loading were determined for the F7 thermosensitive liposome by HPLC. The phase transition temperature of F7 thermosensitive liposome was investigated by differential scanning calorimetry;the liposome morphology was observed by atomic force microscopy;the drug release of liposome was examined by dialysis;and the particle size and zeta potential were measured through Malvern particle size analyzer. The cytotoxicity of F7 and F7 thermosensitive liposome was determined by the MTT method, and the freeze-drying process was optimized using the designexpert software. Results The encapsulation efficiency of F7 thermosensitive liposomes was (97.56±0.22) ％, and the drug loading ratio was (1.51±0.01) ％. The phase transition temperature of F7 thermosensitive liposome was 39.9℃, the zeta potential was (-15.10±0.85) mV, the particle size was (86.94±1.21) nm, and the poly disperse coefficient was 0.17±0.01. Compared with the F7 injection, the F7 thermosensitive liposomes showed a stronger, dose-dependent inhibitory effect on the growth of lung cancer H1299 and breast cancer MCF-7 cells. The freeze-dried powder of liposomes dissolved well with the encapsulation efficiency of 95％ and the particle size of approximately 130 nm. Conclusion The F7 thermosensitive liposome prepared by the pH gradient active drug loading method has high encapsulation efficiency and good stability. The preparation method is simple and feasible for further development of the F7 preparation.
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Objective:To evaluate the effect of the occlusal surface height of a mandibular posterior implant-supported single crown on stress in bone tissues.Methods:Three-dimensional finite element models of the implant-supported single crown replacing the missing right lower second premolar,mesial and distal natural teeth,periodontal membrane,alveolar bone,loaded rigid body and analog food of almond were established.Using the Federation Dentaire International (FDI)system,the first premolar, the second premolar and the first molar were represented with 44,45,46.Three occlusal surface heights of the crown were studied:(1 )normal height;(2)1 5 μm reduction in height;(3)30 μm reduction in height.The models were loaded by independent loading with maximal occlusal force(44 by 280 N,45 by 360 N,and 46 by 480 N)and average occlusal force(44 by 1 40 N,45 by 1 80 N,and 46 by 240 N)on the single crown;combined loading (maximal occlusal force transformed into uniform load of 3 .7 MPa on top of rigid body,in contact with points on the occlusal surface),and analog almond-like food loading (average occlusal force transformed into uniform load of 1 .67 MPa in simulated food chewing,in contact with points on the occlusal surface).Results:For maximal biting force under independent loading,Von Mises stress peak values in bone tissues around 44,45,and 46 were 82.57 MPa,45.26 MPa and 27.79 MPa;For average biting force,peak values were 41 .28 MPa,22.63 MPa and 1 3.89 MPa.Under com-bined loading,compared with the normal occlusal surface height group,Von Mises stress peak values de-creased 4.6 MPa,by 0.84%;increased 7.52 MPa,by 20.04%,and decreased 1 .8 MPa,by 5.84%, for 45,46,and 44 in the 30 μm infra-occlusion group,respectively.Under food loading,Von Mises stress peak values decreased 0.34 MPa,by 1 .62%;increased 1 .1 1 MPa,by 2.66%;and increased 0.06 MPa,by 0.54%,and for 45,46,and 44 in the 30 μm infra-occlusion group,respectively.Con-clusion:Within the limitation of this study,within 30 μm reduction of the occlusal surface height of im-plant-supported single crown,no significant difference of the peak values was observed.
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Objective: To prepare arsenic trioxide (As2O3) liposome, to optimize the formulation of As2O3 liposomes, and to study the feasibility of As2O3 liposomes prepared by the active drug-loading. Methods: Liposomes were prepared by the active drug-loading method. An orthogonal test was utilized to optimize the formulation and preparation of As2O3 liposomes. The unencapsulated As2O3 and liposomes were separated by Sephadex gel G-50 column, the entrapment efficiency (EE) was detected by atomic fluorescence spectrophotometry. The morphological examination of As2O3 liposomes was performed using transmission electron microscopy. The particle size and Zeta potential of the liposomes were measured. The advantage of As2O3 liposomes made by active drug-loading method was investigated. Results: The EE of the liposomes was (72.3 ± 0.8)%, the morphology of liposomes was spherical or ellipsoidal shape with uniform particle size, the mean partical size was (193 ± 12) nm, and Zeta potential was (36.1 ± 3.0) mV. Liposomes have good safety and better stability. Conclusion: The selected formulation and preparation technique of As2O3 liposomes could be rational and stable, and the prepared As2O3 liposomes have good safety.