Angiogenic Type I Collagen Extracellular Matrix Integrated with Recombinant Bacteriophages Displaying Vascular Endothelial Growth Factors

Genetically Engineered Filamentous Bacteriophages Displaying TGF-β1 Promote Angiogenesis in 3D Microenvironments

Combined 3D cell culture in vitro assays with microenvironment-mimicking systems are effective for cell-based screening tests of drug and chemical toxicity. Filamentous bacteriophages have diverse applications in material science, drug delivery, tissue engineering, energy, and biosensor development. Specifically, genetically modified bacteriophages have the potential to deliver therapeutic molecules or genes to targeted tumor tissues. The engineered bacteriophages in this study significantly enhanced endothelial cell migration and tube formation within the extracellular matrix (ECM). Compared to TGF-β1 alone and non-modified phages, the presence of TGF-β1 on the bacteriophages demonstrated superior performance as a continuous stimulant in the microenvironment, effectively promoting these angiogenic processes. Assays, including RT-qPCR, ELISA, and fluorescence microscopy, confirmed the expression of angiogenic markers such as CD31, validating the formation of 3D angiogenic structures. Our findings indicate that the TGF-β1 displayed by bacteriophages likely acted as a chemotactic factor, promoting the migration, proliferation, and tube formation of endothelial cells (ECs) within the ECM. Although direct contact between ECs and bacteriophages was not explicitly confirmed, the observed effects strongly suggest that TGF-β1-RGD bacteriophages contributed to the stimulation of angiogenic processes. The formation of angiogenic structures by ECs in the ECM was confirmed as three-dimensional and regulated by the surface treatment of microfluidic channels. These results suggest that biocompatible TGF-β1-displaying bacteriophages could continuously stimulate the microenvironment in vitro for angiogenesis models. Furthermore, we demonstrated that these functionalized bacteriophages have the potential to be utilized as versatile biomaterials in the field of biomedical engineering. Similar strategies could be applied to develop angiogenic matrices for tissue engineering in in vitro assays.

In vivo safety evaluation and tracing of arginylglycylaspartic acid-engineered phage nanofiber in murine model

The engineered phage YSY184, mimicking the extracellular matrix nanofiber, effectively promotes stem cell differentiation and angiogenesis. This study evaluated its safety in a mouse model, monitoring weight, immunogenicity, spleen immune responses, and macrophage infiltration. Rapid clearance of YSY184 was observed, with peak tissue presence within three hours, significantly reduced by 24 hours, and negligible after one month. No adverse physiological or pathological effects were detected post-administration, affirming YSY184's safety and underscore its potential for therapeutic use, warranting further clinical exploration.

Histochemistry for Molecular Imaging in Nanomedicine

All the nanotechnological devices designed for medical purposes have to deal with the common requirement of facing the complexity of a living organism. Therefore, the development of these nanoconstructs must involve the study of their structural and functional interactions and the effects on cells, tissues, and organs, to ensure both effectiveness and safety. To this aim, imaging techniques proved to be extremely valuable not only to visualize the nanoparticles in the biological environment but also to detect the morphological and molecular modifications they have induced. In particular, histochemistry is a long-established science able to provide molecular information on cell and tissue components in situ, bringing together the potential of biomolecular analysis and imaging. The present review article aims at offering an overview of the various histochemical techniques used to explore the impact of novel nanoproducts as therapeutic, reconstructive and diagnostic tools on biological systems. It is evident that histochemistry has been playing a leading role in nanomedical research, being largely applied to single cells, tissue slices and even living animals.

Biomimetic virus-based soft niche for ischemic diseases

The essential therapeutic cues provided by a nanofibrous arginine-glycine-aspartic acid-engineered M13 phage were exploited as extracellular matrix (ECM)-mimicking niches, contributing to de novo soft tissue niche engineering. The interplay of biomimetic phage cues with surrounding organ tissues was identified, and cells were implanted between tissues to achieve an appropriate soft tissue niche that enables the proper functioning of the implanted stem cells at the injured site. With the polyacrylamide (PA) hydrogel mimicking the soft tissue organ stiffness ranges, it was found that biochemical and topological cues in conjunction with the ∼1-2 kPa elastic and mechanical cues of engineered phage nanofibers in soft tissues efficiently enhance the desired response of implanted stem cells. This phage cue with angiogenic and antioxidant functions overcomes the pathological environment to support implanted cells and surrounding soft tissues at the ischemic site, thereby successfully decreasing myogenic degeneration, minimizing fibrosis, and enhancing blood vessel regeneration with M2 macrophage polarization by improving the survival of the implanted endothelial progenitor cells (EPC) in an ischemic mouse model. These biomimetic phage nanofiber cues are considerably supportive of cell therapy, as they establish promising therapeutic extracellular de novo soft tissue niches for curing ischemic diseases.

Evaluation of Cell-Penetrating Peptides Using Microfluidic In Vitro 3D Brain Endothelial Barrier

In drug delivery to the human brain, blood vessels are a significant hurdle because they restrict the entry of most solutes to protect brain. To overcome this hurdle, an in vitro 3D model for brain endothelial barrier is developed using a microfluidic device with hydrogel providing a 3D extracellular matrix scaffold. Using the model, peptides known to utilize receptor-mediated transcytosis are verified, which has been one of the most promising mechanisms for brain-specific penetration. The cytotoxicity and cellular damage to the peptide are investigated and the receptor-mediated transcytosis and brain endothelial specific penetrating abilities of the peptides in a quantitative manner are demonstrated. As a preclinical test, applying the quantification assays conducted in this study are suggested, including the penetrating ability, cytotoxicity, endothelial damage, and receptor specificity. Using this microfluidic device as an in vitro platform for evaluating various brain targeting drugs and drug carrier candidates is also proposed.