Screening oral drugs for their interactions with the intestinal transportome via porcine tissue explants and machine learning.

In vitro systems that accurately model in vivo conditions in the gastrointestinal tract may aid the development of oral drugs with greater bioavailability. Here we show that the interaction profiles between drugs and intestinal drug transporters can be obtained by modulating transporter expression in intact porcine tissue explants via the ultrasound-mediated delivery of small interfering RNAs and that the interaction profiles can be classified via a random forest model trained on the drug-transporter relationships. For 24 drugs with well-characterized drug-transporter interactions, the model achieved 100% concordance.

Robotically handled whole-tissue culture system for the screening of oral drug formulations.

Monolayers of cancer-derived cell lines are widely used in the modelling of the gastrointestinal (GI) absorption of drugs and in oral drug development. However, they do not generally predict drug absorption in vivo. Here, we report a robotically handled system that uses large porcine GI tissue explants that are functionally maintained for an extended period in culture for the high-throughput interrogation (several thousand samples per day) of whole segments of the GI tract.

Cell-geometry-dependent changes in plasma membrane order direct stem cell signalling and fate.

Cell size and shape affect cellular processes such as cell survival, growth and differentiation, thus establishing cell geometry as a fundamental regulator of cell physiology. The contributions of the cytoskeleton, specifically actomyosin tension, to these effects have been described, but the exact biophysical mechanisms that translate changes in cell geometry to changes in cell behaviour remain mostly unresolved. Using a variety of innovative materials techniques, we demonstrate that the nanostructure and lipid assembly within the cell plasma membrane are regulated by cell geometry in a ligand-independent manner.

Flexible piezoelectric devices for gastrointestinal motility sensing.

Improvements in ingestible electronics with the capacity to sense physiological and pathophysiological states have transformed the standard of care for patients. Yet, despite advances in device development, significant risks associated with solid, non-flexible gastrointestinal transiting systems remain. Here, we report the design and use of an ingestible, flexible piezoelectric device that senses mechanical deformation within the gastric cavity.

Triggerable tough hydrogels for gastric resident dosage forms.

Systems capable of residing for prolonged periods of time in the gastric cavity have transformed our ability to diagnose and treat patients. Gastric resident systems for drug delivery, ideally need to be: ingestible, be able to change shape or swell to ensure prolonged gastric residence, have the mechanical integrity to withstand the forces associated with gastrointestinal motility, be triggerable to address any side effects, and be drug loadable and release drug over a prolonged period of time. Materials that have been primarily utilized for these applications have been largely restricted to thermoplastics and thermosets.

Preventing tissue fibrosis by local biomaterials interfacing of specific cryptic extracellular matrix information.

Matrix metalloproteinases (MMPs) contribute to the breakdown of tissue structures such as the basement membrane, promoting tissue fibrosis. Here we developed an electrospun membrane biofunctionalized with a fragment of the laminin β1-chain to modulate the expression of MMP2 in this context. We demonstrate that interfacing of the β1-fragment with the mesothelium of the peritoneal membrane via a biomaterial abrogates the release of active MMP2 in response to transforming growth factor β1 and rescues tissue integrity ex vivo and in vivo in a mouse model of peritoneal fibrosis.

Sparse feature selection methods identify unexpected global cellular response to strontium-containing materials.

Despite the increasing sophistication of biomaterials design and functional characterization studies, little is known regarding cells' global response to biomaterials. Here, we combined nontargeted holistic biological and physical science techniques to evaluate how simple strontium ion incorporation within the well-described biomaterial 45S5 bioactive glass (BG) influences the global response of human mesenchymal stem cells. Our objective analyses of whole gene-expression profiles, confirmed by standard molecular biology techniques, revealed that strontium-substituted BG up-regulated the isoprenoid pathway, suggesting an influence on both sterol metabolite synthesis and protein prenylation processes.

High resolution Raman spectroscopy mapping of stem cell micropatterns.

We report on the use of high resolution Raman spectroscopy mapping combined with a micro-engineered stem cell platform. This technique obtains quantitative information about the concentration of individual intracellular molecules such as proteins, lipids, and other metabolites, while tightly controlling cell shape and adhesion. This new quantitative analysis will prove highly relevant for in vitro drug screening applications and regenerative medicine.

Comparative assessment of the stability of nonfouling poly(2-methyl-2-oxazoline) and poly(ethylene glycol) surface films: an in vitro cell culture study.

Poly(ethylene glycol) (PEG) has been the most frequently reported and commercially used polymer for surface coatings to convey nonfouling properties. PEGylated surfaces are known to exhibit limited chemical stability, particularly due to oxidative degradation, which limits long-term applications. In view of excellent anti-adhesive properties in the brush conformation and resistance to oxidative degradation, poly(2-methyl-2-oxazoline) (PMOXA) has been proposed recently as an alternative to PEG.

Extracellular vesicles derived from preosteoblasts influence embryonic stem cell differentiation.

Embryonic stem cells (ESCs) can differentiate into all cell types of the body and, therefore, hold tremendous promise for cell-based regenerative medicine therapies. One significant challenge that should be addressed before using ESCs in the clinic is to improve methods of efficiently and effectively directing the differentiation of this heterogeneous cell population. The work presented here examines the potential of harnessing naturally derived extracellular vesicles to deliver genetic material from mature cells to undifferentiated ESCs for the purpose of manipulating stem cell fate.

Correlative Light-Ion Microscopy for biological applications.

Here we report a new technique, Correlative Light-Ion Microscopy (CLIM), to correlate SEM-like micrographs with fluorescence images. This technique presents significant advantages over conventional methods in enabling topographical and biochemical information to be correlated with nanoscale resolution without destroying the fluorescence signal. We demonstrate the utility of CLIM for a variety of investigations of cell substrate interactions validating its potential to become a routine procedure in biomedical research.

Formation and characterization of DNA-polymer-condensates based on poly(2-methyl-2-oxazoline) grafted poly(L-lysine) for non-viral delivery of therapeutic DNA.

Successful gene delivery systems deliver DNA in a controlled manner combined with minimal toxicity and high transfection efficiency. Here we investigated 15 different copolymers of poly(l-lysine)-graft-poly(2-methyl-2-oxazoline) (PLL-g-PMOXA) of variable grafting densities and PMOXA molecular weights for their potential to complex and deliver plasmid DNA. PLL(20)g(7)PMOXA(4) formed at N/P charge ratio of 3.