Profiling native pulmonary basement membrane stiffness using atomic force microscopy.

Mammalian cells sense and react to the mechanics of their immediate microenvironment. Therefore, the characterization of the biomechanical properties of tissues with high spatial resolution provides valuable insights into a broad variety of developmental, homeostatic and pathological processes within living organisms. The biomechanical properties of the basement membrane (BM), an extracellular matrix (ECM) substructure measuring only ∼100-400 nm across, are, among other things, pivotal to tumor progression and metastasis formation.

Early Detection of Cartilage Degeneration: A Comparison of Histology, Fiber Bragg Grating-Based Micro-Indentation, and Atomic Force Microscopy-Based Nano-Indentation.

We have determined the sensitivity and detection limit of a new fiber Bragg grating (FBG)-based optoelectronic micro-indenter for biomechanical testing of cartilage and compared the results to indentation-type atomic force microscopy (IT-AFM) and histological staining. As test samples, we used bovine articular cartilage, which was enzymatically degraded ex vivo for five minutes using different concentrations of collagenase (5, 50, 100 and 500 µg/mL) to mimic moderate extracellular matrix deterioration seen in early-stage osteoarthritis (OA). Picrosirius Red staining and polarization microscopy demonstrated gradual, concentration-dependent disorganization of the collagen fibrillar network in the superficial zone of the explants.

Precision 3D-Printed Cell Scaffolds Mimicking Native Tissue Composition and Mechanics.

Cellular dynamics are modeled by the 3D architecture and mechanics of the extracellular matrix (ECM) and vice versa. These bidirectional cell-ECM interactions are the basis for all vital tissues, many of which have been investigated in 2D environments over the last decades. Experimental approaches to mimic in vivo cell niches in 3D with the highest biological conformity and resolution can enable new insights into these cell-ECM interactions including proliferation, differentiation, migration, and invasion assays.

Pilus-1 Backbone Protein RrgB of Streptococcus pneumoniae Binds Collagen I in a Force-Dependent Way.

Attachment to host tissue is a prerequisite for successful host colonization and invasion of pathogens. Many pathogenic bacteria use surface appendices, called pili, to bind and firmly attach to host tissue surfaces. Although it has been speculated that the laterally positioned D3 domain of the pilus-1 backbone protein RrgB of Streptococcus pneumoniae may promote bacterial-host interaction, via adhesion to extracellular matrix molecules, such as collagen, earlier studies showed no affinity of RrgB to collagen I.

Aggrecan Hypomorphism Compromises Articular Cartilage Biomechanical Properties and Is Associated with Increased Incidence of Spontaneous Osteoarthritis.

The gene encoding the proteoglycan aggrecan () is abundantly expressed in cartilage during development and adulthood, and the loss or diminished deposition of the protein results in a wide range of skeletal malformations. Furthermore, aggrecan degradation is a hallmark of cartilage degeneration occurring in osteoarthritis. In the present study, we investigated the consequences of a partial loss of aggrecan in the postnatal skeleton and in the articular cartilage of adult mice.

Fibrin glue displays promising in vitro characteristics as a potential carrier of adipose progenitor cells for tissue regeneration.

Adipose-derived multipotent stem/progenitor cells (ASPCs) were shown to be ideal candidates for cell-based regenerative therapies. Yet, despite their huge potential, successful clinical applications are still rare. It was suggested that the efficacy of ASPCs at the recipient site depends on the vehicle of cell delivery.

Sacrificial-layer free transfer of mammalian cells using near infrared femtosecond laser pulses.

Laser-induced cell transfer has been developed in recent years for the flexible and gentle printing of cells. Because of the high transfer rates and the superior cell survival rates, this technique has great potential for tissue engineering applications. However, the fact that material from an inorganic sacrificial layer, which is required for laser energy absorption, is usually transferred to the printed target structure, constitutes a major drawback of laser based cell printing.