Influence of different surface treatments of poly(n-butyl acrylate) networks on fibroblasts adhesion, morphology and viability

Two-Photon Direct Laser Writing of 3D Scaffolds through C, H-Insertion Crosslinking in a One-Component Material System

The popularity of two-photon direct laser writing in biological research is remarkable as this technique is capable of 3D fabrication of microstructures with unprecedented control, flexibility and precision. Nevertheless, potential impurities such as residual monomers and photoinitiators remaining unnoticed from the photopolymerization in the structures pose strong challenges for biological applications. Here, the first use of high-precision 3D microstructures fabricated from a one-component material system (without monomers and photoinitiators) as a 3D cell culture platform is demonstrated. The material system consists of prepolymers with built- in crosslinker motieties, requiring only aliphatic C, H units as reaction partners following two-photon excitation. The material is written by direct laser writing using two-photon processes in a solvent-free state, which enables the generation of structures at a rapid scan speed of up to 500 mm s-1 with feature sizes scaling down to few micrometers. The generated structures possess stiffnesses close to those of common tissue and demonstrate excellent biocompatibility and cellular adhesion without any additional modification. The demonstrated approach holds great promise for fabricating high-precision complex 3D cell culture scaffolds that are safe in biological environments.

PCL/Gelatin/Graphene Oxide Electrospun Nanofibers: Effect of Surface Functionalization on In Vitro and Antibacterial Response

The emergence of resistance to pathogenic bacteria has resulted from the misuse of antibiotics used in wound treatment. Therefore, nanomaterial-based agents can be used to overcome these limitations. In this study, polycaprolactone (PCL)/gelatin/graphene oxide electrospun nanofibers (PGO) are functionalized via plasma treatment with the monomeric groups diallylamine (PGO-M1), acrylic acid (PGO-M2), and tert-butyl acrylate (PGO-M3) to enhance the action against bacteria cells. The surface functionalization influences the morphology, surface wettability, mechanical properties, and thermal stability of PGO nanofibers. PGO-M1 and PGO-M2 exhibit good antibacterial activity against Staphylococcus aureus and Escherichia coli, whereas PGO-M3 tends to reduce their antibacterial properties compared to PGO nanofibers. The highest proportion of dead bacteria cells is found on the surface of hydrophilic PGO-M1, whereas live cells are colonized on the surface of hydrophobic PGO-M3. Likewise, PGO-M1 shows a good interaction with L929, which is confirmed by the high levels of adhesion and proliferation with respect to the control. All the results confirm that surface functionalization can be strategically used as a tool to engineer PGO nanofibers with controlled antibacterial properties for the fabrication of highly versatile devices suitable for different applications (e.g., health, environmental pollution).

Interaction between extracellular cancer matrix and stromal breast cells

INTRODUCTION

Stromal-epithelial interactions are fundamental for normal organ development and there is a multitude of evidence that the different components of the microenvironment are also necessary for the maintenance and promotion of the "tumor organ". Deregulated tumor associated extracellular matrix (tECM) is a hallmark of cancer, causing an alteration in the amount and composition of the different components (i.e. proteins, proteoglycans, glycoproteins and polysaccharids) of the ECM. As epithelial-stromal interactions are reciprocal, it is possible that tECM itself is able to initiate tumor development. We therefore established a mouse model to examine the influence of tECM of murine breast cancer on developing breast tissue in mice.

MATERIALS AND METHODS

Breast cancer was established in 5 BALB/c mice by subcutaneous injection of 1×106 4T1 cells in 100μl PBS into the left mammary fat pad. The mammary fat pad including the primary tumor was excised after two weeks, decellularised and labelled as tumor extracellular matrix (tECM). Tumor ECM of 4T1 tumors was implanted into the 4th inguinal mammary fat pad of BALB/c mice (n = 5) aged 5 days. After 12 weeks the fourth mammary fat pad including the primary tumor was excised. Tissue was used for paraffin embedding and mouse breast cancer PCR array. Murine breast cancer tissue (BCT) and normal murine breast tissue (BT) served as control.

RESULTS

Gene array analysis of 84 breast cancer-specific transcripts revealed that the mammary gland cells which were exposed to tumor ECM (tECM-BT) showed a similarly high overexpression for 22 genes as apparent for breast cancer tissue (BCT). The corresponding scatter plot showed a high agreement in the expression of the examined genes between the mammary gland cells which were exposed to tumor ECM and the breast cancer tissue.

DISCUSSION

Our results clearly demonstrate that the tECM is able to shift the gene expression pattern of murine mammary epithelial cells towards that of carcinoma, indicating a role in breast cancer initiation. These data underlines that the acellular component of the tumor (ECM) can lead to a transformation of mammary gland tissue cells. These data show for the first time that the interaction of normal breast tissue cells with tumor ECM leads to an exchange of information and a consecutive overexpression of tumor-specific genes.