Microarrays
The Bradley Group
has worked in the micro-array area for some four years and has led to the
development of a generic HT screening method for the determination of the
substrate specificity of proteases, kinases and phosphatases etc. (Interfacing
DNA Arrays with Combinatorial Libraries, Chem. Commun., 2005 and the last paper
2006 presents a 10,000 member peptide library). With time interest in
micro-arrays has been extended to include arrays based around small molecule
and polymer based transfection agents (Polyplexes and Lipoplexes for Mammalian
Gene Delivery (see: Traditional to Micro-array Screening, Combinatorial
Chemistry and High-Throughput Screening, 2004, 447, in which libraries of small
molecules within polymers were screened for their cellular transfection
abilities (delivery of DNA into cells). This is important in so called
gene therapy or antisense
studies. Thus there is a need to be able to efficiently deliver DNA (or
RNAi) into cells. This project aims to produce new reagents, tools and methods
for DNA delivery.
Cell microarray
Stem cell control
and manipulation
The Bradley group has developed so called polymer
micro-arrays. This is in essence a glass microscope slide with 2,000 different
polymers printed in a spot like manner across the array. This array can then be
screened with mammalian cells to identify polymers that are cell selective. We
are currently interested in preparing arrays that will allow cell release, of
finding polymers that will allow small molecules to be placed in the array to
modulate cell phenotype (physical changes). Currently, a new approach to
transfect mammalian cells on polymer microarray platforms has been achieved.
Cellular Delivery
The successful and efficient introduction and delivery of
materials into cells is of fundamental importance throughout many areas of
biology. It is critical for the analysis of function, the perturbation of
specific cellular processes, and the development of novel therapeutic
strategies. The Bradley group has carried out numerous studies with small,
mono-disperse, cross-linked beads (we can routinely prepare a variety of
cross-linked beads from 200 nm - 5 µm) on a variety of cultured cell lines.
Remarkably, and quite generally, these beads are taken up by cells These
particles have a number of advantages over other approaches. Firstly, a diverse
range of compounds can be attached to the microspheres including small molecule
inhibitors, peptides, RNA and DNA. They are large enough to visualise using
standard microscopy techniques (unlike nano-particles). They are not diluted
within the cell. Populations of cells containing beads can be readily sorted
automatically from other cells for subsequent analysis and it is possible to
get very high uptake rates (this can be modulated through alteration of the
bead size and incubation time).
HT Physical
Organic Chemistry
The research group routinely uses high-thorough chemical
methods to prepare chemical entities (why make one when in the same time you
can make 10!). However to date little has been carried out in the area of
utilising HT methods in physical organic chemistry for reaction predication,
mechanistic interrogation and reaction profiling. We have begun to look at
tools and chemistries to allow Hammett plots and reaction predictions to be
determined by mass spectrometry with a single injection on an LCMS allowing
complete interrogation and interpretation of a reaction. This research offers
an approach that will enable the first steps to be taken forward for HT
reaction prediction and the generation of kinetic parameters and challenges
current philosophy in offering new methods orders of magnitude faster than
those currently used.
Combinatorial
Chemistry
Combinatorial chemistry evolved from work in the area of
peptide chemistry, specially from the need to produce large munbers of products
either by preparing single compounds in parallel synthesis or by preparing many
compounds simultaneously in mixtures. Using combinatorial techniques these
large numbers of compounds can be prepared in a faster, more efficient and
cheaper way and can give rise to millions of compounds. These compounds can
then be screened for the desired property (e.g. a new catalytic activity,
enzyme inhibitor). Combinatorial Chemistry is now widely applied within the
pharmaceutical industry as a means of identifying new leads (through random
screens) and optimising the potency of feasible drug candidates (lead
optimisation).
