Surface Modified Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) And Its Antibacterial Action

Polyhydroxyalkanoates has been proved to have a bright future in biomedicalengineering due to its great biocompatibility and degradation property. And P(3HB-4HB) isone of the most promising materials. Its machanical property can be widely adjusted fromplastic-like to rubber-like by changing the content of3HB and4HB, making it more useful asbiomaterial.Clinical usage of biomaterials can be influenced by infection problem. But themechanism of infection provides us that constructing an anti-protein surface can improve theantimicrobial ability of the biomaterials. After implantation of biomaterials, the protein layerformed on the surface and it can be easily adhered by bacteria and promote the formation ofbiofilm, which will significantly increase the drug resistance of bacteria.In this paper, the P(3HB-4HB)-based material was modified by plasma treatment andlayer-by-layer self assembly to build an antibacterial surfaces against the bacteria adhension.P(3HB-4HB)+PAMAM antibacterial surface coating was constructed from the plasmatreatment. After treating with oxygen plasma, P(3HB-4HB) material was immersed in thePAMAM solution to get an antibacterial surface coated with PAMAM dendrimer（P(3HB-4HB)+PAMAM. The XPS spectrogram and the zeta potential curve indicated thatthe PAMAM dendrimer had been coated onto the surface. Static contact angle data showedthat the surface wettability was improved after coating. QCM-D was performed to analyze theamount of coating and its interaction with BSA. The results illustrated that the amount ofPAMAM coating along with the adhered BSA increased with the plasma treating time. Theresults of antibacterial tests indicated that P(3HB-4HB)+PAMAM has significant antibacterialproperty against E. coli attached to the surface. It can also resist the E. coli from solution. Andthe property lasted until14days of degradation.The HA/PAMAM antibacterial coating was constructed by layer-by-layer-self-assembly.P(3HB-4HB) was immersed in HA solution and PAMAM solution alternately after treatedwith PEI solution to get a HA/PAMAM antibacterial surface coating. The XPS spectrogram,static contact angle data and the zeta potential curve indicated that the surface ofP(3HB-4HB) was formed a PEI layer after immersing PEI solution. The procedure of self assembly was followed by QCM-D and the individual property of every single layer wascharacterized using zeta potential. The results showed that the self assembly layers weresuccessfully achieved. And the detail information of the HA/PAMAM layers was gained byQ-Tools。The interaction between the Layers and BSA was analyzed using the QCM-D, theresults showed that both the HA layers and the PAMAM layers can resist the adhension ofprotein. The antibacterial tests indicated that the LBL treatment improved the antibacterialproperty against E. coli of the surface significantly. It can also resist the E. coli from solution.And the property lasted until14days of degradation.