Delivery of Endothelial Cell-Laden Microgel Elicits Angiogenesis in Self-Assembling Ultrashort Peptide Hydrogels In Vitro

Abstract

Blood vessel generation is an essential process for tissue formation, regeneration, and repair. Notwithstanding, vascularized tissue fabrication in vitro remains a challenge, as current fabrication techniques and biomaterials lack translational potential in medicine. Naturally derived biomaterials harbor the risk of immunogenicity and pathogen transmission, while synthetic materials need functionalization or blending to improve their biocompatibility. In addition, the traditional top-down fabrication techniques do not recreate the native tissue microarchitecture. Self-assembling ultrashort peptides (SUPs) are promising chemically synthesized natural materials that self-assemble into three-dimensional nanofibrous hydrogels resembling the extracellular matrix (ECM). Here, we use a modular tissue-engineering approach, embedding SUP microgels loaded with human umbilical vein endothelial cells (HUVECs) into a 3D SUP hydrogel containing human dermal fibroblast neonatal (HDFn) cells to trigger angiogenesis. The SUPs IVFK and IVZK were used to fabricate microgels that gel in a water-in-oil emulsion using a microfluidic droplet generator chip. The fabricated SUP microgels are round structures that are 300–350 μm diameter in size and have ECM-like topography. In addition, they are stable enough to keep their original size and shape under cell culture conditions and long-term storage. When the SUP microgels were used as microcarriers for growing HUVECs and HDFn cells on the microgel surface, cell attachment, stretching, and proliferation could be demonstrated. Finally, we performed an angiogenesis assay in both SUP hydrogels using all SUP combinations between micro- and bulky hydrogels. Endothelial cells were able to migrate from the microgel to the surrounding area, showing angiogenesis features such as sprouting, branching, coalescence, and lumen formation. Although both SUP hydrogels support vascular network formation, IVFK outperformed IVZK in terms of vessel network extension and branching. Overall, these results demonstrated that cell-laden SUP microgels have great potential to be used as a microcarrier cell delivery system, encouraging us to study the angiogenesis process and to develop vascularized tissue-engineering therapies.

Peptide nanogels as a scaffold for fabricating dermal grafts and 3D vascularized skin models

“… 2 These biocompatible peptide hydrogels have been shown to have promising applications in various biomedical applications such as tissue engineering, drug delivery, regenerative medicine, microbiology, and biosensing. 3 – 9 …”

Green Synthesis of Silver-Peptide Nanoparticles Generated by the Photoionization Process for Anti-Biofilm Application

“…All peptide sequences were synthesized on rink amide resin (1 mmol) using the Fmoc-based solid-phase peptide synthesis (SPPS) method according to the previous publication. 22 First, the resin was pre-swelled in dichloromethane (DCM) solution for 30 min, and then, the Fmoc-protecting group on resin was removed by adding 20% (v/v) piperidine/ dimethylformamide (DMF). The resin was subsequently rinsed thoroughly with DMF and DCM.…”

“…Inspired by the high viability of the in situ synthesis of Ag NPs within peptide hydrogel, we took advantage of an ultrashort self-assembling peptide containing only four natural amino acids, namely, Ac-IVFK-NH 2 , − to generate a colloidal solution of hybrid peptide/Ag NPs (IVFK/Ag NPs) under extended UV light exposure. This fabrication process allows for a more environmentally friendly generation of Ag NPs through substituting toxic precursors with biocompatible peptide molecules.…”

Synthesis and Organization of Gold-Peptide Nanoparticles for Catalytic Activities

“…Ultrashort amphiphilic peptides, a class of peptides containing three to seven amino acids, can self-assemble into a well-defined nanofibrous network, mimicking the native extracellular matrix. 20,21 Such kinds of short peptides have been used in many applications in medicine and tissue engineering, such as bioprinting, 22,23 drug delivery, 24 engineered tissue models, 25,26 and wound healing, 27 which reveal the biocompatibility of peptides. In our previous works, we have reported the photochemical synthesis of size-controlled biocompatible silver nanoparticles in the absence of any chemical reducing agents for antibacterial applications.…”