Bacteria adhesion and biofilm formation have raised severe problems on public health, food industry and many other areas. A variety of reagents and surface coatings have been developed to kill bacteria and/or limit their interaction with surfaces. It has also attracted many efforts to integrate different bactericidal elements together and maximize antibacterial efficiency. Herein, we review mechanisms for both passive and active approaches to resist and kill bacteria respectively, and discuss integrated strategies based on these two approaches. We also offer perspective on future research direction.
Khoo X, Grinstaff M W. Novel infection-resistant surface coatings: A bioengineering approach. MRS Bulletin, 2011, 36: 357–366
2
Costerton J W, Lewandowski Z, Caldwell D E, Korber D R, Lappin-Scott H M. Microbial biofilms. Annual Review of Microbiology, 1995, 49: 711–745
3
Donlan R M. Biofilm formation: A clinically relevant microbiological process. Clinical Infectious Diseases, 2001, 33: 1387–1392
4
Srey S, Jahid I K, Ha S D. Biofilm formation in food industries: A food safety concern. Food Control, 2013, 31: 572–585
5
Cheng G, Li G, Xue H, Chen S, Bryers J D, Jiang S. Zwitterionic carboxybetaine polymer surfaces and their resistance to long-term biofilm formation. Biomaterials, 2009, 30: 5234–5240
6
Cheng G, Zhang Z, Chen S, Bryers J D, Jiang S. Inhibition of bacterial adhesion and biofilm formation on zwitterionic surfaces. Biomaterials, 2007, 28: 4192–4199
7
Saldarriaga F I C, van der Mei H C, Lochhead M J, Grainger D W, Busscher H J. The inhibition of the adhesion of clinically isolated bacterial strains on multi-component cross-linked poly(ethylene glycol)-based polymer coatings. Biomaterials, 2007, 28: 4105–4112
8
Samal S K, Dash M, van Vlierberghe S, Kaplan D L, Chiellini E, van Blitterswijk C, Moroni L, Dubruel P. Cationic polymers and their therapeutic potential. Chemical Society Reviews, 2012, 41: 7147–7194
9
Vinsova J, Vavrikova E. Recent advances in drugs and prodrugs design of chitosan. Current Pharmaceutical Design, 2008, 14: 1311–1326
10
Liu H, Du Y, Wang X, Sun L. Chitosan kills bacteria through cell membrane damage. International Journal of Food Microbiology, 2004, 95: 147–155
11
Li P, Poon Y F, Li W, Zhu H Y, Yeap S H, Cao Y, Qi X, Zhou C, Lamrani M, Beuerman R W, Kang E T, Mu Y, Li C M, Chang M W, Jan L S S, Chan-Park M B. A polycationic antimicrobial and biocompatible hydrogel with microbe membrane suctioning ability. Nature Materials, 2011, 10: 149–156
12
Milović N M, Wang J, Lewis K, Klibanov A M. Immobilized n-alkylated polyethylenimine avidly kills bacteria by rupturing cell membranes with no resistance developed. Biotechnology and Bioengineering, 2005, 90: 715–722
13
Tiller J C, Liao C J, Lewis K, Klibanov A M. Designing surfaces that kill bacteria on contact. Proceedings of the National Academy of Sciences of the United States of America, 2001, 98: 5981–5985
14
Lin J, Qiu S, Lewis K, Klibanov A M. Mechanism of bactericidal and fungicidal activities of textiles covalently modified with alkylated polyethylenimine. Biotechnology and Bioengineering, 2003, 83: 168–172
15
Vaara M. Agents that increase the permeability of the outer membrane. Microbiological Reviews, 1992, 56: 395–411
16
Helander I M, Alakomi H L, Latva-Kala K, Koski P. Polyethyleneimine is an effective permeabilizer of gram-negative bacteria. Microbiology, 1997, 143(Pt 10): 3193–3199
17
Khalil H, Chen T, Riffon R, Wang R, Wang Z. Synergy between polyethylenimine and different families of antibiotics against a resistant clinical isolate of Pseudomonas aeruginosa. Antimicrobial Agents and Chemotherapy, 2008, 52: 1635–1641
18
Reddy K V R, Yedery R D, Aranha C. Antimicrobial peptides: Premises and promises. International Journal of Antimicrobial Agents, 2004, 24: 536–547
19
Oren Z, Shai Y. Mode of action of linear amphipathic α-helical antimicrobial peptides. Peptide Science, 1998, 47: 451–463
20
Boman H G, Marsh J, Goode J A. Antimicrobial Peptides. John Wiley & Sons, 1994
21
Cudic M, Otvos L Jr. Intracellular targets of antibacterial peptides. Current Drug Targets, 2002, 3: 101–106
22
Rapsch K, Bier F F, Tadros M, von Nickisch-Rosenegk M. Identification of antimicrobial peptides and immobilization strategy suitable for a covalent surface coating with biocompatible properties. Bioconjugate Chemistry, 2014, 25: 308–319
23
Webb J, Spencer R. The role of polymethylmethacrylate bone cement in modern orthopaedic surgery. Journal of Bone and Joint Surgery. British Volume, 2007, 89: 851–857
24
Jaeblon T. Polymethylmethacrylate: Properties and contemporary uses in orthopaedics. Journal of the American Academy of Orthopaedic Surgeons, 2010, 18: 297–305
25
Schwalbe R, Steele-Moore L, Goodwin A C. Antimicrobial Susceptibility Testing Protocols. Abingdon: CRC Press, 2007
26
Finberg R W, Moellering R C, Tally F P, Craig W A, Pankey G A, Dellinger E P, West M A, Joshi M, Linden P K, Rolston K V, Rotschafer J C, Rybak M J. The importance of bactericidal drugs: Future directions in infectious disease. Clinical Infectious Diseases, 2004, 39: 1314–1320
27
Høiby N, Bjarnsholt T, Givskov M, Molin S, Ciofu O. Antibiotic resistance of bacterial biofilms. International Journal of Antimicrobial Agents, 2010, 35: 322–332
28
Stewart P S, William Costerton J. Antibiotic resistance of bacteria in biofilms. Lancet, 2001, 358: 135–138
29
Nemoto K, Hirota K, Ono T, Murakami K, Murakami K, Nagao D, Miyake Y. Effect of varidase (streptokinase) on biofilm formed by Staphylococcus aureus. Chemotherapy, 2000, 46: 111–115
30
Yasuda H, Ajiki Y, Koga T, Kawada H, Yokota T. Interaction between biofilms formed by Pseudomonas aeruginosa and clarithromycin. Antimicrobial Agents and Chemotherapy, 1993, 37: 1749–1755
31
Belly R, Kydd G. Silver resistance in microorganisms. Developments in Industrial Microbiology, 1982, 23: 567–578
32
Bragg P, Rainnie D. The effect of silver ions on the respiratory chain of Escherichia coli. Canadian Journal of Microbiology, 1974, 20: 883–889
33
Siddhartha S, Tanmay B, Arnab R, Gajendra S, Ramachandrarao P, Debabrata D. Characterization of enhanced antibacterial effects of novel silver nanoparticles. Nanotechnology, 2007, 18: 225103
34
Prabhu S, Poulose E. Silver nanoparticles: Mechanism of antimicrobial action, synthesis, medical applications, and toxicity effects. International Nano Letters, 2012, 2: 1–10
35
Russell A D, Hugo W B. Antimicrobial activity and action of silver. Progress in Medicinal Chemistry, 1994, 31: 351–370
36
Ip M, Lui S L, Poon V K, Lung I, Burd A. Antimicrobial activities of silver dressings: An in vitro comparison. Journal of Medical Microbiology, 2006, 55: 59–63
37
Gupta A, Silver S. Silver as a biocide: Will resistance become a problem? Nature Biotechnology, 1998, 16: 888
38
Hu R, Li G, Jiang Y, Zhang Y, Zou J J, Wang L, Zhang X. Silver-zwitterion organic-inorganic nanocomposite with antimicrobial and antiadhesive capabilities. Langmuir, 2013, 29: 3773–3779
39
Kim J S, Kuk E, Yu K N, Kim J H, Park S J, Lee H J, Kim S H, Park Y K, Park Y H, Hwang C Y, Kim Y K, Lee Y S, Jeong D H, Cho M H. Antimicrobial effects of silver nanoparticles. Nanomedicine; Nanotechnology, Biology, and Medicine, 2007, 3: 95–101
40
Li P, Li J, Wu C, Wu Q, Li J. Synergistic antibacterial effects of β-lactam antibiotic combined with silver nanoparticles. Nanotechnology, 2005, 16: 1912
41
Ruparelia J P, Chatterjee A K, Duttagupta S P, Mukherji S. Strain specificity in antimicrobial activity of silver and copper nanoparticles. Acta Biomaterialia, 2008, 4: 707–716
42
Kim Y H. Choi Y, Kim K M, Choi S Y. Evaluation of copper ion of antibacterial effect on Pseudomonas aeruginosa, Salmonella typhimurium and Helicobacter pylori and optical, mechanical properties. Applied Surface Science, 2012, 258: 3823–3828
43
Solioz M, Stoyanov J V. Copper homeostasis in enterococcus hirae. FEMS Microbiology Reviews, 2003, 27: 183–195
44
Parker A, Paul R, Power G. Electrochemistry of the oxidative leaching of copper from chalcopyrite. Journal of Electroanalytical Chemistry and Interfacial Electrochemistry, 1981, 118: 305–316
45
Kitching R, Chapman H, Hughes J. Levels of activity as indicators of sublethal impacts of copper contamination and salinity reduction in the intertidal gastropod, polinices incei philippi. Marine Environmental Research, 1987, 23: 79–87
46
Cioffi N, Torsi L, Ditaranto N, Tantillo G, Ghibelli L, Sabbatini L, Bleve-Zacheo T, D’Alessio M, Zambonin P G, Traversa E. Copper nanoparticle/polymer composites with antifungal and bacteriostatic properties. Chemistry of Materials, 2005, 17: 5255–5262
47
Vaseashta A, Dimova-Malinovska D. Nanostructured and nanoscale devices, sensors and detectors. Science and Technology of Advanced Materials, 2005, 6: 312–318
48
Comini E. Metal oxide nano-crystals for gas sensing. Analytica Chimica Acta, 2006, 568: 28–40
49
Yoon K Y, Hoon Byeon J, Park J H, Hwang J. Susceptibility constants of Escherichia coli and Bacillus subtilis to silver and copper nanoparticles. Science of the Total Environment, 2007, 373: 572–575
50
Chatterjee A K, Chakraborty R, Basu T. Mechanism of antibacterial activity of copper nanoparticles. Nanotechnology, 2014, 25: 135101
51
Liaudet L, Soriano F G, Szabó C. Biology of nitric oxide signaling. Critical Care Medicine, 2000, 28(37): 52
52
Tarr H L A. Bacteriostatic action of nitrates. Nature, 1941, 147: 417–418
53
Zumft W G. The biological role of nitric oxide in bacteria. Archives of Microbiology, 1993, 160: 253–264
54
Mancinelli R L. Mckay C P. Effects of nitric oxide and nitrogen dioxide on bacterial growth. Applied and Environmental Microbiology, 1983, 46: 198–202
55
Wink D A, Mitchell J B. Chemical biology of nitric oxide: Insights into regulatory, cytotoxic, and cytoprotective mechanisms of nitric oxide. Free Radical Biology & Medicine, 1998, 25: 434–456
56
Kono Y, Shibata H, Adachi K, Tanaka K. Lactate-dependent killing of Escherichia coli by nitrite plus hydrogen-peroxide: A possible role of nitrogen dioxide. Archives of Biochemistry and Biophysics, 1994, 311: 153–159
57
Nablo B J, Schoenfisch M H. Antibacterial properties of nitric oxide-releasing sol-gels. Journal of Biomedical Materials Research. Part A, 2003, 67: 1276–1283
58
Major T C, Brisbois E J, Jones A M, Zanetti M E, Annich G M, Bartlett R H, Handa H. The effect of a polyurethane coating incorporating both a thrombin inhibitor and nitric oxide on hemocompatibility in extracorporeal circulation. Biomaterials, 2014, 35: 7271–7285
59
Gupta S, Amoako K A, Suhaib A, Cook K E. Multi-modal, surface-focused anticoagulation using poly-2-methoxyethylacrylate polymer grafts and surface nitric oxide release. Advanced Materials Interfaces, 2014, 1, DOI:10.1002/admi.201400012
60
Amoako K A, Montoya P J, Major T C, Suhaib A B, Handa H, Brant D O, Meyerhoff M E, Bartlett R H, Cook K E. Fabrication and in vivo thrombogenicity testing of nitric oxide generating artificial lungs. Journal of Biomedical Materials Research. Part A, 2013, 101: 3511–3519
61
Zwischenberger J B, Anderson C M, Cook K E, Lick S D, Mockros L F, Bartlett R H. Development of an implantable artificial lung: Challenges and progress. ASAIO Journal (American Society for Artificial Internal Organs), 2001, 47: 316–320
62
Chapman R G, Ostuni E, Liang M N, Meluleni G, Kim E, Yan L, Pier G, Warren H S, Whitesides G M. Polymeric thin films that resist the adsorption of proteins and the adhesion of bacteria. Langmuir, 2001, 17: 1225–1233
63
Ista L K, Fan H, Baca O, López G P. Attachment of bacteria to model solid surfaces’ oligo(ethylene glycol) surfaces inhibit bacterial attachment. FEMS Microbiology Letters, 1996, 142: 59–63
64
Jeon S I, Lee J H, Andrade J D, De Gennes P G. Protein—surface interactions in the presence of polyethylene oxide. I. Simplified theory. Journal of Colloid and Interface Science, 1991, 142: 149–158
65
Zhao C, Li L, Wang Q, Yu Q, Zheng J. Effect of film thickness on the antifouling performance of poly (hydroxy-functional methacrylates) grafted surfaces. Langmuir, 2011, 27: 4906–4913
66
Lin N J, Yang H S, Chang Y, Tung K L, Chen W H, Cheng H W, Hsiao S W, Aimar P, Yamamoto K, Lai J Y. Surface self-assembled pegylation of fluoro-based pvdf membranes via hydrophobic-driven copolymer anchoring for ultra-stable biofouling resistance. Langmuir, 2013, 29: 10183–10193
67
Li M, Neoh K G, Xu L Q, Wang R, Kang E T, Lau T, Olszyna D P, Chiong E. Surface modification of silicone for biomedical applications requiring long-term antibacterial, antifouling, and hemocompatible properties. Langmuir, 2012, 28: 16408–16422
68
Yang W J, Cai T, Neoh K G, Kang E T, Teo S L M, Rittschof D. Barnacle cement as surface anchor for “clicking” of antifouling and antimicrobial polymer brushes on stainless steel. Biomacromolecules, 2013, 14: 2041–2051
69
Weber T, Bechthold M, Winkler T, Dauselt J, Terfort A. Direct grafting of anti-fouling polyglycerol layers to steel and other technically relevant materials. Colloids and Surfaces. B, Biointerfaces, 2013, 111: 360–366
70
Kuroki H, Tokarev I, Nykypanchuk D, Zhulina E, Minko S. Stimuli-responsive materials with self-healing antifouling surface via 3d polymer grafting. Advanced Functional Materials, 2013, 23: 4593–4600
71
Ekblad T, Bergstrm G, Ederth T, Conlan S L, Mutton R, Clare A S, Wang S, Liu Y, Zhao Q, D’Souza F. Poly (ethylene glycol)-containing hydrogel surfaces for antifouling applications in marine and freshwater environments. Biomacromolecules, 2008, 9: 2775–2783
72
Mi L, Jiang S. Integrated antimicrobial and nonfouling zwitterionic polymers. Angewandte Chemie International Edition, 2014, 53: 1746–1754
73
Ishihara K, Fukumoto K, Iwasaki Y, Nakabayashi N. Modification of polysulfone with phospholipid polymer for improvement of the blood compatibility. Part 2. Protein adsorption and platelet adhesion. Biomaterials, 1999, 20: 1553–1559
74
Iwasaki Y, Sawada S, Ishihara K, Khang G, Lee H B. Reduction of surface-induced inflammatory reaction on plga/mpc polymer blend. Biomaterials, 2002, 23: 3897–3903
75
Chang Y, Liao S C, Higuchi A, Ruaan R C, Chu C W, Chen W Y. A highly stable nonbiofouling surface with well-packed grafted zwitterionic polysulfobetaine for plasma protein repulsion. Langmuir, 2008, 24: 5453–5458
76
West S L, Salvage J P, Lobb E J, Armes S P, Billingham N C, Lewis A L, Hanlon G W, Lloyd A W. The biocompatibility of crosslinkable copolymer coatings containing sulfobetaines and phosphobetaines. Biomaterials, 2004, 25: 1195–1204
77
Zhang Z, Zhang M, Chen S, Horbett T A, Ratner B D, Jiang S. Blood compatibility of surfaces with superlow protein adsorption. Biomaterials, 2008, 29: 4285–4291
78
Holmlin R E, Chen X, Chapman R G, Takayama S, Whitesides G M. Zwitterionic sams that resist nonspecific adsorption of protein from aqueous buffer. Langmuir, 2001, 17: 2841–2850
79
Shengfu Chen Z C, Jiang S. Ultra-low fouling peptide surfaces derived from natural amino acids. Biomaterials, 2009, 30: 5892–5896
80
Chen S, Li L, Zhao C, Zheng J. Surface hydration. Principles and applications toward low-fouling/nonfouling biomaterials. Polymer, 2010, 51: 5283–5293
81
Jiang S, Cao Z. Ultralow-fouling, functionalizable, and hydrolyzable zwitterionic materials and their derivatives for biological applications. Advanced Materials, 2010, 22: 920–932
82
Cao Z, Jiang S. Super-hydrophilic zwitterionic poly(carboxybetaine) and amphiphilic non-ionic poly(ethylene glycol) for stealth nanoparticles. Nano Today, 2012, 7: 404–413
83
Keefe A J, Jiang S. Poly(zwitterionic)protein conjugates offer increased stability without sacrificing binding affinity or bioactivity. Nature Chemistry, 2012, 4: 59–63
84
Ji J, Zhu H, Shen J. Surface tailoring of poly(dl-lactic acid) by ligand-tethered amphiphilic polymer for promoting chondrocyte attachment and growth. Biomaterials, 2004, 25: 1859–1867
85
Leng C, Han X, Shao Q, Zhu Y, Li Y, Jiang S, Chen Z. In situ probing of the surface hydration of zwitterionic polymer brushes: Structural and environmental effects. Journal of Physical Chemistry C, 2014, 118: 15840–15845
86
McRae Page S, Henchey E, Chen X, Schneider S, Emrick T. Efficacy of polympc-dox prodrugs in 4t1 tumor-bearing mice. Molecular Pharmaceutics, 2014, 11: 1715–1720
87
Disabb-Miller M L, Zha Y, DeCarlo A J, Pawar M, Tew G N, Hickner M A. Water uptake and ion mobility in cross-linked bis(terpyridine)ruthenium-based anion exchange membranes. Macromolecules, 2013, 46: 9279–9287
88
Ye S H, Hong Y, Sakaguchi H, Shankarraman V, Luketich S K, D'Amore A, Wagner W R. Nonthrombogenic, biodegradable elastomeric polyurethanes with variable sulfobetaine content. ACS Applied Materials & Interfaces, 2014, 6: 22796–22806
89
Hook A L, Chang C Y, Yang J, Luckett J, Cockayne A, Atkinson S, Mei Y, Bayston R, Irvine D J, Langer R. Combinatorial discovery of polymers resistant to bacterial attachment. Nature Biotechnology, 2012, 30: 868–875
90
Hook A L, Chang C Y, Yang J, Atkinson S, Langer R, Anderson D G, Davies M C, Williams P, Alexander M R. Discovery of novel materials with broad resistance to bacterial attachment using combinatorial polymer microarrays. Advanced Materials, 2013, 25: 2542–2547
91
Bjarnsholt T, Ciofu O, Molin S, Givskov M, Hoiby N. Applying insights from biofilm biology to drug development—Can a new approach be developed? Nature Reviews. Drug Discovery, 2013, 12: 791–808
92
Klibanov A M. Permanently microbicidal materials coatings. Journal of Materials Chemistry, 2007, 17: 2479–2482
93
Zou P, Hartleb W, Lienkamp K. It takes walls and knights to defend a castle—synthesis of surface coatings from antimicrobial and antibiofouling polymers. Journal of Materials Chemistry, 2012, 22: 19579–19589
94
Brogden K A. Antimicrobial peptides: Pore formers or metabolic inhibitors in bacteria? Nature Reviews. Microbiology, 2005, 3: 238–250
95
Arciola C R, Montanaro L, Caramazza R, Sassoli V, Cavedagna D. Inhibition of bacterial adherence to a high-water-content polymer by a water-soluble, nonsteroidal, anti-inflammatory drug. Journal of Biomedical Materials Research, 1998, 42: 1–5
96
Cheng G, Xue H, Li G, Jiang S. Integrated antimicrobial and nonfouling hydrogels to inhibit the growth of planktonic bacterial cells and keep the surface clean. Langmuir, 2010, 26: 10425–10428
97
Ratte H T. Bioaccumulation and toxicity of silver compounds: A review. Environmental Toxicology and Chemistry, 1999, 18: 89–108
98
Follmann H D M, Martins A F, Gerola A P, Burgo T A L, Nakamura C V, Rubira A F, Muniz E C. Antiadhesive and antibacterial multilayer films via layer-by-layer assembly of tmc/heparin complexes. Biomacromolecules, 2012, 13: 3711–3722
99
Wong S Y, Han L, Timachova K, Veselinovic J, Hyder M N, Ortiz C, Klibanov A M, Hammond P T. Drastically lowered protein adsorption on microbicidal hydrophobic/hydrophilic polyelectrolyte multilayers. Biomacromolecules, 2012, 13: 719–726
100
Zhuk I, Jariwala F, Attygalle A B, Wu Y, Libera M R, Sukhishvili S A. Self-defensive layer-by-layer films with bacteria-triggered antibiotic release. ACS Nano, 2014, 8: 7733–7745
101
Shukla A, Fleming K E, Chuang H F, Chau T M, Loose C R, Stephanopoulos G N, Hammond P T. Controlling the release of peptide antimicrobial agents from surfaces. Biomaterials, 2010, 31: 2348–2357
102
Fu J, Ji J, Yuan W, Shen J. Construction of anti-adhesive and antibacterial multilayer films via layer-by-layer assembly of heparin and chitosan. Biomaterials, 2005, 26: 6684–6692
103
Cheng G, Xue H, Zhang Z, Chen S, Jiang S. A switchable biocompatible polymer surface with self-sterilizing and nonfouling capabilities. Angewandte Chemie International Edition, 2008, 47: 8831–8834
104
Wang B L, Ren K F, Chang H, Wang J L, Ji J. Construction of degradable multilayer films for enhanced antibacterial properties. ACS Applied Materials & Interfaces, 2013, 5: 4136–4143
105
Cao Z, Brault N, Xue H, Keefe A, Jiang S. Manipulating sticky and non-sticky properties in a single material. Angewandte Chemie, 2011, 50: 6102–6104
106
Cao Z, Mi L, Mendiola J, Ella-Menye J R, Zhang L, Xue H, Jiang S. Reversibly switching the function of a surface between attacking and defending against bacteria. Angewandte Chemie, 2012, 51: 2602–2605
107
Cao B, Tang Q, Li L, Humble J, Wu H, Liu L, Cheng G. Switchable antimicrobial and antifouling hydrogels with enhanced mechanical properties. Advanced Healthcare Materials, 2013, 2: 1096–1102
108
Cao B, Li L, Tang Q, Cheng G. The impact of structure on elasticity, switchability, stability and functionality of an all-in-one carboxybetaine elastomer. Biomaterials, 2013, 34: 7592–7600
109
Yu Q, Cho J, Shivapooja P, Ista L K, López G P. Nanopatterned smart polymer surfaces for controlled attachment, killing, and release of bacteria. ACS Applied Materials & Interfaces, 2013, 5: 9295–9304
110
Azzaroni O, Moya S, Farhan T, Brown A A, Huck W T S. Switching the properties of polyelectrolyte brushes via “hydrophobic collapse”. Macromolecules, 2005, 38: 10192–10199
111
Shen Y, Zhang Y, Zhang Q, Niu L, You T, Ivaska A. Immobilization of ionic liquid with polyelectrolyte as carrier. Chemical Communications, 2005, 2005: 4193–4195
112
Wang L, Lin Y, Su Z. Counterion exchange at the surface of polyelectrolyte multilayer film for wettability modulation. Soft Matter, 2009, 5: 2072–2078
113
Wei Q, Cai M, Zhou F, Liu W. Dramatically tuning friction using responsive polyelectrolyte brushes. Macromolecules, 2013, 46: 9368–9379
114
Huang C J, Chen Y S, Chang Y. Counterion-activated nanoactuator: Reversibly switchable killing/releasing bacteria on polycation brushes. ACS Applied Materials & Interfaces, 2015, 7: 2415–2423