De Novo Design of a Bolaamphiphilic Peptide
with Only Natural Amino Acids
Feng Qiu, Yongzhu Chen, Chengkang Tang, Qinghan Zhou, Chen Wang,
Ying-Kang Shi, Xiaojun Zhao*
Introduction
Molecular self-assembly as a novel approach to develop
advanced materials has been regarded as the biomimetics
on the nanometer scale and has attracted considerable
attention in recent years. Molecular self-assembling
systems have been derived from natural biomolecules
such as lipids, peptides, and nucleic acids by following
nature’s leads. Among the emerging self-assembling
molecules, self-assembling peptides are taking an increasingly
significant role for their simplicity in design and
versatility in application.[1] In the past decade, the area of
self-assembling peptides has been developed rapidly and
many chimerical self-assembling peptide systems have
been designed.[2] These designed materials typically
include ionic self-complementary peptides,[3] peptide
inks,[4] peptide detergents,[5] and peptide-amphiphiles
(PAs)[6]. These materials have been widely applied in
nanotechnology and nanobiomedical technology such as
F. Qiu, Y. Chen, C. Tang, Q. Zhou, X. Zhao
Institute for Nanobiomedical Technology and Membrane Biology,
West China Hospital, Sichuan University, Chengdu, 610041,
P. R. China
Fax: þ86-028-8516-4072;
X. Zhao
Center for Biomedical Engineering, NE47-379, Massachusetts
Institute of Technology, Cambridge, MA 02139-4307, USA
Y.-K. Shi, X. Zhao
West China Medical School, West China Hospital,
Sichuan University, Guo Xue Xiang 37, Chengdu, 610041,
Chengdu, P. R. China
X. Zhao
State Key Lab of Biotherapy of Human Diseases, Cancer Center,
West China Hospital, West China Medical School, Sichuan
University, Guo Xue Xiang 37, Chengdu, Sichuan, P. R. China
C. Wang
National Center of Nanoscience and Technology, Beijing 100080,
P. R. China
A new self-assembling bolaamphiphilic peptide has been designed and synthesized using only
natural amino acids. This simple peptide is composed of two lysines connected by 4–8 alanines
to maintain the characteristics of the traditional bolaamphiphiles. Based on an irregular
secondary structure, it can self-assemble into nanospheres,
nanorods, or nanofibers with lengths up to
micrometers. The long nanofibers can be broken into
smaller fragments by sonication, however, they
could reassemble into nanofibers after incubation.
Furthermore, the nanostructures were shown to
have considerable thermostability. This new
bolaamphiphilic peptide differs from any other
self-assembling peptides or bolaamphiphiles, and
possibly provides a new approach to fabricate nanomaterials.
Macromol. Biosci. 2008, 8, 1053–1059
2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/mabi.200800180 1053
three-dimensional (3D) cell cultures,[7] regenerative medicine,[
8] drug delivery systems,[9] and membrane protein
stabilization.[10]
Bolaamphiphiles are another category of self-assembling
molecules. They contain two hydrophilic head
groups connected by a hydrophobic spacer. Such molecules
are well known as derivates of archaeal lipids, which can
self-assemble into monolayer membranes with considerable
mechanical stability. A number of researches have
confirmed that bolaamphiphiles are excellent candidates
for the fabrication of nanostructures such as membranemimetic
films,[11] nanotubes,[12] nanofibers,[13] and helical
ribbons.[14] In recent years, materials derived from
bolaamphiphiles have attracted increasing attention for
their potential applications including nanotube templates
for metallic nanowires,[15] membrane-mimetic films for
bioactive functions,[16] and nanovesicles for drug and gene
delivery,[17] which makes them promising new materials
for nanotechnology and nanobiomedicine.
The exploitation of advancedmaterials for drug and gene
carriers is one of the most concerned issues for designing
self-assemblingmolecules. In our attempts to exploit a new
type of self-assembling peptide as a drug and gene delivery
system, we for the first time combined the advantages of
both self-assembling peptides and bolaamphiphiles, and
fabricated a novel bolaamphiphilic peptide by mimicking
the structure of a lipid bilayer. To our knowledge, although
the hydrophilic heads within all the existing bolaamphiphiles
have been designed as components of various
structures ranging from common chemical groups to
functional bioactive groups,[18] almost all the bolaamphiphiles
employ alkyls or their analogueswith various length
