In this work, the plastic of polylatic acid(PLA) film is coated by alumina(Al_2O_3)through dielectric barrier discharge plasma assisted atomic layer deposition(DBD PA-ALD) for the proposal of the barrier property enha...In this work, the plastic of polylatic acid(PLA) film is coated by alumina(Al_2O_3)through dielectric barrier discharge plasma assisted atomic layer deposition(DBD PA-ALD) for the proposal of the barrier property enhancement. The influence of ALD Al_2O_3 thickness on properties of barrier, mechanical, optical and degradation is investigated in detail. It is obtained that the growth rate of Al_2O_3 in DBD PA-ALD is as quick as 0.12 nm/cycle. After coated～40 nm Al_2O_3, the water vapor transmission rate of PLA is reduced by two orders of magnitude.Additionally, it is noticed that the tension strength of the coated film is improved slightly,whereas the light transmission rate is decreased with the increase of Al_2O_3 thickness. The degradation test shows that Al_2O_3 coating almost does not affect the self-degradation rate of PLA film.展开更多
The type V-I CRISPR-Cas system is becoming increasingly more attractive for genome editing.However,natural nucleases of this system often exhibit low efficiency,limiting their application.Here,we used structure-guided...The type V-I CRISPR-Cas system is becoming increasingly more attractive for genome editing.However,natural nucleases of this system often exhibit low efficiency,limiting their application.Here,we used structure-guided rational design and protein engineering to optimize an uncharacterized Cas12i nuclease,Cas12i3.As a result,we developed Cas-SF01,a Cas12i3 variant that exhibits significantly improved gene editing activity in mammalian cells.Cas-SF01 shows comparable or superior editing performance compared to SpCas9 and other Cas12 nucleases.Compared to natural Cas12i3,Cas-SF01 has an expanded PAM range and effectively recognizes NTTN and noncanonical NATN and TTVN PAMs.In addition,we identified an amino acid substitution,D876R,that markedly reduced the off-target effect while maintaining high on-target activity,leading to the development of CasSF01^(HiFi)(high-fidelity Cas-SF01).Finally,we show that Cas-SF01 has high gene editing activities in mice and plants.Our results suggest that CasSF01 can serve as a robust gene editing platform with high efficiency and specificity for genome editing applications in various organisms.展开更多
基金supported by National Natural Science Foundation of China (Nos. 11775028, 11505013)Beijing Municipal National Science Foundation (Nos. 4162024, KM201510015009)the Collaborative Innovation Center of Green Printing & Publishing Technology (No. 20160113)
文摘In this work, the plastic of polylatic acid(PLA) film is coated by alumina(Al_2O_3)through dielectric barrier discharge plasma assisted atomic layer deposition(DBD PA-ALD) for the proposal of the barrier property enhancement. The influence of ALD Al_2O_3 thickness on properties of barrier, mechanical, optical and degradation is investigated in detail. It is obtained that the growth rate of Al_2O_3 in DBD PA-ALD is as quick as 0.12 nm/cycle. After coated～40 nm Al_2O_3, the water vapor transmission rate of PLA is reduced by two orders of magnitude.Additionally, it is noticed that the tension strength of the coated film is improved slightly,whereas the light transmission rate is decreased with the increase of Al_2O_3 thickness. The degradation test shows that Al_2O_3 coating almost does not affect the self-degradation rate of PLA film.
基金This work was supported by Shandong BellaGen Biotechnology,and by a grant from the National Natural Science Foundation of China(32188102 to J.-K.Z.).
文摘The type V-I CRISPR-Cas system is becoming increasingly more attractive for genome editing.However,natural nucleases of this system often exhibit low efficiency,limiting their application.Here,we used structure-guided rational design and protein engineering to optimize an uncharacterized Cas12i nuclease,Cas12i3.As a result,we developed Cas-SF01,a Cas12i3 variant that exhibits significantly improved gene editing activity in mammalian cells.Cas-SF01 shows comparable or superior editing performance compared to SpCas9 and other Cas12 nucleases.Compared to natural Cas12i3,Cas-SF01 has an expanded PAM range and effectively recognizes NTTN and noncanonical NATN and TTVN PAMs.In addition,we identified an amino acid substitution,D876R,that markedly reduced the off-target effect while maintaining high on-target activity,leading to the development of CasSF01^(HiFi)(high-fidelity Cas-SF01).Finally,we show that Cas-SF01 has high gene editing activities in mice and plants.Our results suggest that CasSF01 can serve as a robust gene editing platform with high efficiency and specificity for genome editing applications in various organisms.
