*                        
                        
                            Corresponding authors
                                                                                                            
                    
                    
                        
                                a
                        
                        
                            Institute of Materials Research and Engineering, A*STAR, 3 Research Link, Singapore 117602
                                                                                                            
                    
                    
                        
                                b
                        
                        
                            Department of Pharmacology, Center for Translational Medicine, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore 117597
                                
                                E-mail:
                                    peter_wong@nuhs.edu.sg                                                                                                            
                    
                    
                        
                                c
                        
                        
                            Department of Biomedical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575
                                
                                E-mail:
                                    eyim@nus.edu.sg                                                                                                            
                    
                    
                        
                                d
                        
                        
                            Department of Chemistry, Division of Biomedical Engineering, Institute for Advanced Study, State Key Laboratory of Molecular Neuroscience, and Institute of Molecular Functional Materials, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China
                                                                                                            
                    
                    
                        
                                e
                        
                        
                            Mechanobiology Institute Singapore, National University of Singapore, 5A Engineering Drive 1, Singapore 117411
                                                                                                            
                    
                    
                        
                                f
                        
                        
                            Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, NUHS Tower Block, IE Kent Ridge Road, Singapore 119228
                                                                                                            
                    
                    
                        
                                g
                        
                        
                            SCUT-HKUST Joint Research Laboratory, Guangdong Innovative Research Team, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, China
                                                                                                            
                    
                    
                        
                                h
                        
                        
                            Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117585
                                
                                E-mail:
                                    cheliub@nus.edu.sg                                                                                        
                                Fax: +65-67791936                                                            
                                Tel: +65-65168049