Biomedical subjects

N Bachrach

Publications and source records attributed to N Bachrach.

4 recordsLinked to original sources

PubMed2003

Cutaneous wound analysis using hyperspectral imaging.

A correlative bright-field and hyperspectral analysis of full-thickness, cutaneous wounds in a porcine model was undertaken to investigate the efficacy of hyperspectral imaging as an alternate method for wound identification. Analysis of a randomly selected specimen yielded distinct spectral signatures for cutaneous regions of interest including the epidermis, injured dermis, and normal dermis. The scanning of the entire specimen group using these hyperspectral signatures revealed an exclusionary, pseudo-color pattern whereby a central wound region was consistently defined by a unique spectral signature. An algorithm was derived as an objective tool for the comparison of the wound regions defined by the hyperspectral classification versus the pathologists' manual tracings. The dimensions of the wound identified in the hyperspectral assay did not differ significantly from the wound region identified by the pathologists using standard bright-field microscopy. These data indicate that hyperspectral analysis may provide a high-throughput alternative for wound estimation that approximates standard bright-field imaging and pathologist evaluation.

Algorithms↗

PubMed2001

Effects of carbodiimide crosslinking conditions on the physical properties of laminated intestinal submucosa.

Functional tissue engineering of load-bearing repair tissues requires the design and production of biomaterials that provide a remodelable scaffold for host infiltration and tissue regeneration while maintaining the repair function throughout the remodeling process. Layered constructs have been fabricated from chemically and mechanically cleaned porcine intestinal collagen using ethyl-3(3-dimethylamino) propyl carbodiimide (EDC) and an acetone solvent. By varying the concentration of the crosslinker from 1 to 10 mM and the solvent from 0 to 90% acetone, the strength, stiffness, maximum strain, thermal stability, lamination strength, and suture retention strength can be adjusted. These parameters have either functional importance or the potential to modify the remodeling kinetics, or they have both. This study investigates the interdependence of these parameters, the specific effects that variations in concentration can achieve, and how the two crosslinking variables interact. The results demonstrate that there is substantial latitude in the design of these constructs by these straightforward crosslinking modifications. These data provide the basis for studying the in vivo response to crosslinking conditions that will supply the requisite strength while still allowing host cell infiltration and remodeling.

Acetone↗

PubMed2000

Mechanical evaluation and design of a multilayered collagenous repair biomaterial.

One method of fabricating implantable biomaterials is to utilize biologically derived, chemically modified tissues to form constructs that are both biocompatible and remodelable. Rigorous mechanical characterization is a necessary component in material evaluation to ensure that the constructs will withstand in vivo loading. In this study we performed an in-depth biaxial mechanical and quantitative structural analysis of GraftPatch (GP), a biomaterial constructed by assembling chemically treated layers of porcine small intestinal submucosa (SIS). The mechanical behavior of GP was compared to both native SIS and to glutaraldehyde-treated bovine pericardium (GLBP) as a reference biomaterial. Under biaxial loading, GP was found to be stiffer than native SIS and mechanically anisotropic, with the preferred fiber direction demonstrating greater stiffness. Quantitative structural analysis using small-angle light scattering indicated a uniform fiber structure similar to GLBP and SIS. To enable test-protocol-independent quantitative comparisons, the biaxial mechanical data were fit to an orthotropic constitutive model, which indicated a similar degree of mechanical anisotropy between the three groups. We also demonstrate how the constitutive model can be used to design layered biocomposite materials that can undergo large deformations.

Animals↗

PubMed2000

A novel injectable collagen matrix: in vitro characterization and in vivo evaluation.

We present here a unique engineered collagen formulation that is injectable and compacts into a porous viscoelastic solid after implantation, achieving completely focal application without cross-linking. This implant provides a cohesive continuously porous matrix, as demonstrated by permeability and compression experiments. Those experiments also provide initial mechanical characterization of the material and establish the ability to modify these essential properties by design. Further, the short-term compaction and long-term stability of the implant in vivo in terms of both physical and histological responses are assessed in an animal model to demonstrate the mechanism of action and long-term persistence of this novel material.

Animals↗