Future challenges in the in vitro and in vivo evaluation of biomaterial biocompatibility

As the science and engineering of biomaterials continues to expand with increased emphasis on the development of nanomaterials and tissue engineering scaffolds,emphasis also must be placed on appropriate and adequate approaches to the in vivo and in vitro evaluation of biomaterial biocompatibility/biological response evaluation.This article presents six topic areas that should be addressed by investigators as they move forward in the development of new systems for regenerative medicine.Most certainly,there are other areas that require attention to detail and a more complete understanding of the strengths and weaknesses of various experimental approaches to biomaterial/biological response evaluation.The small number of issues addressed in this article is only meant to bring to the attention of prospective investigators and authors,the importance of the development of adequate and appropriate evaluation techniques that address the unique features of biomaterials utilized in the development of new medical devices.

Lactosylated N-Alkyl polyethylenimine coated iron oxide nanoparticles induced autophagy in mouse dendritic cells

Dendritic cell(DC)-based vaccines have shown promising therapeutic results in cancer and some immune disorders.It is critical to track in vivo migration behaviours of DCs and monitor the whole process dynamically and non-invasively.Superparamagnetic iron oxide(SPIO)nanoparticles are chosen for DC labelling under magnetic resonance imaging(MRI)because of their proven biosafety as contrast agents.However,when used for cell labelling,sensitive biological indicators such as cell autophagy may be helpful to better understand the process and improve the probe design.Here,lactosylated N-Alkyl polyethylenimine coated SPIO nanoparticles are used for DC labelling.This probe shows satisfactory cell labelling efficiency and low cytotoxicity.In this study,autophagy was used as a key factor to understand how DCs react to nanoparticles after labelling.Our results demonstrate that the nanoparticles can induce protective autophagy in DCs,as inhibition of the autophagy flux could lead to cell death.Meanwhile,the nanoparticles induced autophagy could promote DC maturation which is an essential process for its migration and antigen presentation.Autophagy induced DC maturation is known to enhance the vaccine functions of DCs,therefore,our results suggest that beyond the MRI tracking ability,this probe might enhance therapeutic immune activation as well.

Foreword

This special issue of Regenerative Biomaterials presents 13 manuscriptsprovided by participants of the China–US Forum on GrandChallenges for Biomaterials in the 21st Century. This forum washeld on November 17, 2015, in Chengdu, China and was chaired bythe Editor of Regenerative Biomaterials, Professor Xingdong Zhangand Professor Nicholas Peppas. The participants of this forum wereinternationally recognized experts from the United States ofAmerica and the Peoples Republic of China. It is noteworthy thatthe United States speakers were members of the National Academyof Engineering, Section 2. Bioengineering, and most of the Chinesespeakers were members of the Chinese Academy of Engineering orthe Chinese Academy of Sciences. The overlying theme of this forumand this resultant special issue is the impact that the biological environmentin which biomaterials will be utilized is now recognized asproviding a wide variety of significant and impactful challenges thatmust be overcome if biomaterials are to achieve clinical application.