Recent developments in functional organic polymer coatings for biomedical applications in implanted devices

Organic polymer coatings have been commonly used in biomedical field,which play an important role in achieving biological antifouling,drug delivery,and bacteriostasis.With the continuous development of polymer science,organic polymer coatings can be designed with complex and advanced functions,which is conducive to the construction of biomedical materials with different performances.According to different physical and chemical properties of materials,biomedical organic polymer coating materials are classified into zwitterionic polymers,non-ionic polymers,and biomacromolecules.The strategies of combining coatings with substrates include physical adsorption,chemical grafting,and self-adhesion.Though the coating materials and construction methods are different,many biomedical polymer coatings have been developed to achieve excellent performances,i.e.,enhanced lubrication,anti-inflammation,antifouling,antibacterial,drug release,anti-encrustation,anti-thrombosis,etc.Consequently,a large number of biomedical polymer coatings have been used in artificial lungs,ureteral stent,vascular flow diverter,and artificial joints.In this review,we summarize different types,properties,construction methods,biological functions,and clinical applications of biomedical organic polymer coatings,and prospect future direction for development of organic polymer coatings in biomedical field.It is anticipated that this review can be useful for the design and synthesis of functional organic polymer coatings with various biomedical purposes.

An online monitoring system for atmospheric nitrous acid(HONO) based on stripping coil and ion chromatography

A new instrument for measuring atmospheric nitrous acid（HONO） was developed,consisting of a double-wall glass stripping coil sampler coupled with ion chromatography（SC-IC）.SC-IC is featured by small size（50 × 35 × 25 cm） and modular construction,including three independent parts：the sampling unit,the transfer and supporting unit,and the detection unit.High collection efficiency（〉 99%） was achieved with 25 μmol/L Na2CO3 as absorption solution even in the presence of highly acidic compounds.This instrument has a detection limit of 8 pptv at 15 min time resolution,with a measurement uncertainty of 7%.Potential interferences from NOx,NO2＋SO2,NO2＋VOCs,HONO＋O3,HNO3,peroxyacetyl nitrite（PAN） and particle nitrite were quantified in laboratory studies and were found to be insignificant under typical atmospheric conditions.Within the framework of the 3C-STAR project,inter-comparison between the SC-IC and LOPAP（long path liquid absorption photometer） was conducted at a rural site in the Pearl River Delta.Good agreement was achieved between the two instruments over three weeks.Both instruments determined a clear diurnal profile of ambient HONO concentrations from 0.1 to 2.5 ppbv.However,deviations were found for low ambient HONO concentrations（i.e.〈 0.3 ppbv）,which cannot be explained by previous investigated interference species.To accurately determine the HONO budget under illuminated conditions,more intercomparison of HONO measurement techniques is still needed in future studies,especially at low HONO concentrations.