Self-replication is ubiquitous in the living world but artificial self-replication has been elusive. We have developed a process for self-replication of an arbitrary seed made from nanometer scale DNA tiles. The tiles are constructs of 10 DNA strands which form a bent triple helix, BTX, with four lateral single strands -- ‘sticky ends’ -- for recognition and hybridization with complementary tiles, and six longitudinal sticky ends for joining tiles to form a sequence.
Recent physics research shows how spin-orbit coupling can rearrange
electronic bands in a solid to make a "topological insulator" a new
quantum phase of matter that is guaranteed to have conductive surfaces
even though its bulk is insulating. What happens if you take a
topological insulator and compress or expand it? A team of researchers
at the University of Pennsylvania has examined this question.
In 2008 The Penn MRSEC assisted a high school science teacher, Schuyler
Patton, to prepare a year-long elective course on materials science for
his high school, Central HS, Philadelphia. It started with one class of
33 students and it was very successful. In 2010-11, it was expanded to
two sections with 66 students. In summer 2010, the Penn MRSEC offered a
series of three hands-on workshops for teachers based on the laboratory
experiments used in this course. The themes of these workshops were a)
thermal properties and b) mechanical properties.
In conjunction with the NOVA TV science program, the Penn MRSEC
collaborated with Penn and Drexel University Materials Science
Departments to arrange the first Philly Materials Science & Engineering Day
on Feb. 5, 2011, which introduced the general public in the
Philadelphia region to the world of materials. An extensive program was
arranged that included demonstrations from many LRSM graduate research
groups. More than 30 MRSEC faculty, staff and students participated.
The topological insulating materials offer conductive surface states
that can be useful for quantum computing, catalysis, and other
applications. In this recent work, we (Young, Chowdhury, Walter, Mele,
Kane, and Rappe, under review, 2011) show that compressing the material
strengthens the topological insulating state, while expanding the
material eventually takes this behavior away completely. Using external
pressure as a control parameter suggests general ways to strengthen
this important physical effect.
Protein assembly at the air-water interface (AWI) occurs naturally in
many biological processes, and provides a method for creating ordered
biomaterials. However, the factors that control protein self-assembly at
the AWI are generally not well understood. Here, we describe the
behavior of a model protein, human serum albumin minimally labeled with
Texas Red dye (HSA-TR), using a new confocal microscopy technique
(Figure 1).
The objective of this Seed is to understand cooperative electronic,
optical and electromagnetic phenomena emerging from the interactions of
nanoscale building blocks. Recent work encompasses synthesis of
nanoparticles (figure right) and nanowires, and the investigation of how
nanocrystals can drive geometrical rearrangement in polymersome
micelles (figure right). A second breakthrough (figure below), developed
a ligand exchange process that enables flexible electronic devices
(FETs) based on nanocrystal assemblies
Pioneering experiments reported [upper left] the ability of
ferroelectric domain orientation to switch surface chemistry on and off,
finding unambiguous evidence that the polarity of a ferroelectric
surface can have a strong impact on the energetics of physisorption.
We have developed analytic methods that establish molecular
constraints to photochemical efficiency in the engineering and
construction of molecular photochemical materials and devices useful to
addressing the global energy challenge. The absence, to-date, of
analytic procedures has seriously handicapped progress in the
development of photochemical devices. The new methods will provide
important precise engineering guidelines to photochemical device
construction in the future.
We have designed specialized protein molecules that organize around
carbon nanotubes into an atomistically-predefined pattern. Targeted
design of such self-organization is a powerful tool for engineering at
the nano scale. For example, we have shown that our protein/nanotube
hybrid can be used to generate a regularly-spaced array of gold
nano-particle. Shown here is an exciting new concept we are currently
pursuing. We believe that our nanotube/protein complexes can be used to
create a virus-like particle by nucleating the formation of a membrane
mimetic around itself, much like natural enveloped viruses form a lipid
membrane bilayer around their protein capsid core.
Self-replication is ubiquitous in the living world but artificial self-replication has been elusive. We have developed a process for self-replication of an arbitrary seed made from nanometer scale DNA tiles. The tiles are constructs of 10 DNA strands which form a bent triple helix, BTX, with four lateral single strands -- ‘sticky ends’ -- for recognition and hybridization with complementary tiles, and six longitudinal sticky ends for joining tiles to form a sequence.
Recent physics research shows how spin-orbit coupling can rearrange
electronic bands in a solid to make a "topological insulator" a new
quantum phase of matter that is guaranteed to have conductive surfaces
even though its bulk is insulating. What happens if you take a
topological insulator and compress or expand it? A team of researchers
at the University of Pennsylvania has examined this question.
In 2008 The Penn MRSEC assisted a high school science teacher, Schuyler
Patton, to prepare a year-long elective course on materials science for
his high school, Central HS, Philadelphia. It started with one class of
33 students and it was very successful. In 2010-11, it was expanded to
two sections with 66 students. In summer 2010, the Penn MRSEC offered a
series of three hands-on workshops for teachers based on the laboratory
experiments used in this course. The themes of these workshops were a)
thermal properties and b) mechanical properties.
In conjunction with the NOVA TV science program, the Penn MRSEC
collaborated with Penn and Drexel University Materials Science
Departments to arrange the first 
The topological insulating materials offer conductive surface states
that can be useful for quantum computing, catalysis, and other
applications. In this recent work, we (Young, Chowdhury, Walter, Mele,
Kane, and Rappe, under review, 2011) show that compressing the material
strengthens the topological insulating state, while expanding the
material eventually takes this behavior away completely. Using external
pressure as a control parameter suggests general ways to strengthen
this important physical effect.
Protein assembly at the air-water interface (AWI) occurs naturally in
many biological processes, and provides a method for creating ordered
biomaterials. However, the factors that control protein self-assembly at
the AWI are generally not well understood. Here, we describe the
behavior of a model protein, human serum albumin minimally labeled with
Texas Red dye (HSA-TR), using a new confocal microscopy technique
(Figure 1).
The objective of this Seed is to understand cooperative electronic,
optical and electromagnetic phenomena emerging from the interactions of
nanoscale building blocks. Recent work encompasses synthesis of
nanoparticles (figure right) and nanowires, and the investigation of how
nanocrystals can drive geometrical rearrangement in polymersome
micelles (figure right). A second breakthrough (figure below), developed
a ligand exchange process that enables flexible electronic devices
(FETs) based on nanocrystal assemblies
Pioneering experiments reported [upper left] the ability of
ferroelectric domain orientation to switch surface chemistry on and off,
finding unambiguous evidence that the polarity of a ferroelectric
surface can have a strong impact on the energetics of physisorption.
We have developed analytic methods that establish molecular
constraints to photochemical efficiency in the engineering and
construction of molecular photochemical materials and devices useful to
addressing the global energy challenge. The absence, to-date, of
analytic procedures has seriously handicapped progress in the
development of photochemical devices. The new methods will provide
important precise engineering guidelines to photochemical device
construction in the future.
We have designed specialized protein molecules that organize around
carbon nanotubes into an atomistically-predefined pattern. Targeted
design of such self-organization is a powerful tool for engineering at
the nano scale. For example, we have shown that our protein/nanotube
hybrid can be used to generate a regularly-spaced array of gold
nano-particle. Shown here is an exciting new concept we are currently
pursuing. We believe that our nanotube/protein complexes can be used to
create a virus-like particle by nucleating the formation of a membrane
mimetic around itself, much like natural enveloped viruses form a lipid
membrane bilayer around their protein capsid core.