Variations in surface and electrical properties of polytetrafluoroethylene film after plasma-induced grafting of acrylic acid

Polytetrafluoroethylene(PTFE) film was graftpolymerized with acrylic acid(AAc) via a low-temperature plasma technique.The effect of plasma treatment parameters(radio-frequency power and treatment time) on the spin number of free radicals in PTFE film was examined.Attenuated total reflection Fourier transform infrared(ATR-FTIR)spectroscopy,X-ray photoelectron spectroscopy,scanning electron microscopy,and atomic force microscopy were employed to characterize the chemical structure,surface composition,and microstructure of the original PTFE and PTFE-g-PAAc films,respectively,in order to verify the successful graft polymerization of AAc onto a PTFE film surface.Thermogravimetric analysis illustrated that the thermal stability of bulk PTFE film remains unchanged after graft modification.Water contact angle measurements confirmed that the hydrophilicity of PTFE-g-PAAc film was effectively improved as compared to the original PTFE film.The dielectric constant(ε_r) of PTFE-g-PAAc(GD =218 μg/cm^2) film remained invariable,compared to that of the unmodified PTFE film.Nevertheless,the dielectric loss(tanδ) of PTFE film increased considerably,from 0.0002(GD = 0μg/cm^2) to 0.0073(GD = 218 μg/cm^2),which might be due to the increase in surface polarity and moisture resulting from AAc graft modification.In addition,the surface electrical resistance(R_s) of PTFE film decreased slightly,from 131.89(GD = 0 μg/cm^2) to 110.28 Ω cm^2(GD = 218μg/cm^2) after surface modification,but still retained its inherent high impedance.

Immunohistochemical analysis of PD-L1 and tumor-infiltrating immune cells expression in the tumor microenvironment of primary signet ring cell carcinoma of the prostate

Primary signet ring cell carcinoma(SRCC)of the prostate is a rare neoplasm.However,its potential tumorigenic mechanism,clinicopathological features,and prognostic outcome have not been systematically described.To determine the pathogenic mechanism,we detected distributions of programmed cell death-ligand 1(PD-L1),programmed death 1(PD-1),and cellular components in the tumor microenvironment,including tumor-infiltrating lymphocytes(CD4 and CD8),tumor-associated macrophages(TAMs;CD163 and CD68),and tumor-associated fibroblasts(vimentin and alpha-smooth muscle actin[α-SMA]),in tumor tissues from four patients with primary prostatic SRCC compared with corresponding adjacent tissues and tumor tissues from 30 patients with prostate adenocarcinoma(PCa)by immunohistochemical staining.We found higher expression of PD-L1,CD163,and CD68 in primary SRCC specimens than that in both corresponding adjacent nontumor specimens and PCa specimens with different Gleason scores,indicating that TAMs may participate in the malignant biological behavior of primary SRCC of the prostate.For further analysis,we searched electronic journal databases and Surveillance,Epidemiology,and End Results(SEER)to identify 200 eligible patients including our four cases.According to Kaplan–Meier survival curve analysis,patients<68 years old,with radical prostatectomy(RP),Gleason score of 7–8,and lower clinical stage had longer overall survival(OS).Moreover,Cox multivariate analysis indicated that race(hazard ratio[HR]=1.422),surgical approach(HR=1.654),and Gleason score(HR=2.162)were independent prognostic factors for OS.Therefore,primary SRCC of the prostate represents a distinct and aggressive subtype of prostate cancer associated with a higher distribution of PD-L1 and TAMs,which warrants further clinical investigation.

Bioinspired approaches for medical devices

Advances in medical devices have revolutionized the treatment of human diseases,such as stents in occluded coronary artery,left ventricular assist devices in heart failure,pacemakers in arrhythmias,etc.Despite their significance,the development of devices for reducing and avoiding the thrombosis formation,obtaining excellent mechanical performance,and achieving stable electronic physiology remains challenging and unresolved.Fortunately,nature serves as a good resource of inspirations,and brings us endless bioinspired physicochemical ideas to better the development of novel artificial materials and devices that enable us to potentially overcome the unresolved obstacles.Bioinspired approaches,in particularly,owe much of their current development in biology,chemistry,materials science,medicine and engineering to the design and fabrication of advanced devices.The application of bioinspired devices is a burgeoning area in these fields of research.In this perspective,we would take the cardiovascular device as one example to show how these bioinspired approaches could be used to build novel,advanced biomedical devices with precisely controlled functions.Here,bioinspired approaches are utilized to solve issues like thrombogenic,mechanical and electronic physiology problems in medical devices.Moreover,there is an outlook for future challenges in the development of bioinspired medical devices.