Quartz crystal microbalance measurements of mitochondrial depolarization predicting chemically induced toxicity of vascular cells and macrophages.

Quartz crystal microbalances (QCMs) measure mass on the nanogram (ng) scale. We built novel QCMs as toxicity biosensors incorporating living cells. Human endothelial cells or canine macrophages were equilibrated on QCM crystal surfaces until stable oscillation frequencies occurred.

Understanding and correcting for carbon nanotube interferences with a commercial LDH cytotoxicity assay.

The lactate dehydrogenase (LDH) assay accurately quantifies cytotoxicity of chemicals via the measurement of LDH released from damaged cells. In the assay, LDH catalyzes formation of a reporter chromophore that can be quantified spectrophotometrically at its 490 nm peak, a standard assay, and related to the released LDH concentration. However, certain engineered nanomaterials have been reported to produce aberrant values, resulting in inaccurate assessment of toxicity as measured by LDH levels in media.

Dynamic cell adhesion and viscoelastic signatures distinguish normal from malignant human mammary cells using quartz crystal microbalance.

During transformation of a normal cell to a cell capable of forming a cancerous growth, cellular morphology, the cytoskeleton, and focal contacts undergo significant changes. These changes should be capable of being characterized via real-time monitoring of the dynamic cell adhesion process and viscoelastic properties of cells. Here, we describe use of the quartz crystal microbalance (QCM) to distinguish the dynamic cell adhesion signatures of human normal (HMEC) versus malignant (MCF-7) mammary epithelial cells.

Herceptin-directed nanoparticles activated by an alternating magnetic field selectively kill HER-2 positive human breast cells in vitro via hyperthermia.

Purpose: HER-2 is in the EGF tyrosine kinase receptor family, overexpressed by many human cancers and minimally expressed by normal adult tissues. HER-2 expression in human cancers is correlated with reduced survival, increased metastasis, reduced apoptosis and increased proliferation. Herceptin is a humanised mouse antibody that targets and inactivates HER-2.

A living cell quartz crystal microbalance biosensor for continuous monitoring of cytotoxic responses of macrophages to single-walled carbon nanotubes.

Background: Numerous engineered nanomaterials (ENMs) exist and new ENMs are being developed. A challenge to nanotoxicology and environmental health and safety is evaluating toxicity of ENMs before they become widely utilized. Cellular assays remain the predominant test platform yet these methods are limited by using discrete time endpoints and reliance on organic dyes, vulnerable to interference from ENMs.

Extracellular matrix-derived products modulate endothelial and progenitor cell migration and proliferation in vitro and stimulate regenerative healing in vivo.

Most adult mammals heal without restorative replacement of lost tissue and instead form scar tissue at an injury site. One exception is the adult MRL/MpJ mouse that can regenerate ear and cardiac tissue after wounding with little evidence of scar tissue formation. Following production of a MRL mouse ear hole, 2mm in diameter, a structure rapidly forms at the injury site that resembles the amphibian blastema at a limb amputation site during limb regeneration.

BioDome regenerative sleeve for biochemical and biophysical stimulation of tissue regeneration.

Previous research on vertebrate limb regeneration indicates there are several mediating factors involved during the re-growth process. These factors are both biochemical and biophysical. While the phenomenon of adult limb regeneration does not occur naturally in mammalian species, prior research has focused mainly on biochemical modes of stimulating tissue growth and regeneration.

Degradation products of extracellular matrix affect cell migration and proliferation.

Biologic scaffolds composed of extracellular matrix (ECM) are utilized in numerous regenerative medicine applications to facilitate the constructive remodeling of tissues and organs. The mechanisms by which the host remodeling response occurs are not fully understood, but recent studies suggest that both constituent growth factors and biologically active degradation products derived from ECM play important roles. The objective of the present study was to determine if degradation of ECM scaffold materials in vitro by methods that are biochemically and physiologically relevant can yield products that possess chemotactic and/or mitogenic activities for fully differentiated mammalian endothelial cells and undifferentiated multipotential progenitor cells.