1. Peptide-Modified Nano-Bioactive Glass for Targeted Immobilization of Native VEGF
Matthias Schumacher, Pamela Habibović, Sabine van Rijt ACS Appl Mater Interfaces. 2022 Feb 2;14(4):4959-4968. doi: 10.1021/acsami.1c21378. Epub 2022 Jan 18.
A limiting factor in large bone defect regeneration is the slow and disorganized formation of a functional vascular network in the defect area, often resulting in delayed healing or implant failure. To overcome this, strategies that induce angiogenic processes should be combined with potent bone graft substitutes in new bone regeneration approaches. To this end, we describe a unique approach to immobilize the pro-angiogenic growth factor VEGF165 in its native state on the surface of nanosized bioactive glass particles (nBGs) via a binding peptide (PR1P). We demonstrate that covalent coupling of the peptide to amine functional groups grafted on the nBG surface allows immobilization of VEGF with high efficiency and specificity. The amount of coupled peptide could be controlled by varying amine density, which eventually allows tailoring the amount of bound VEGF within a physiologically effective range. In vitro analysis of endothelial cell tube formation in response to VEGF-carrying nBG confirmed that the biological activity of VEGF is not compromised by the immobilization. Instead, comparable angiogenic stimulation was found for lower doses of immobilized VEGF compared to exogenously added VEGF. The described system, for the first time, employs a binding peptide for growth factor immobilization on bioactive glass nanoparticles and represents a promising strategy to overcome the problem of insufficient neovascularization in large bone defect regeneration.
2. Tyrosinase-mediated Peptide Conjugation with Chitosan-coated Gold Nanoparticles
Naomi Sakono, Kosuke Nakamura, Tatsuki Ohshima, Ryoto Hayakawa, Masafumi Sakono Anal Sci. 2019 Jan 10;35(1):79-83. doi: 10.2116/analsci.18SDP03. Epub 2018 Nov 16.
The conjugation of biomolecules, such as protein, sugar, and DNA, with metal nanoparticles is an important technique for bioassay and biomaterial preparation. In this study, we aim to enzymatically immobilize a functional peptide on gold nanoparticles (AuNPs) using a single-step reaction. We used tyrosinase, a catechol oxidase, to immobilize an enzymatic peptide. We performed immobilization experiments of a fluorescent compound-linked caspase-3 substrate peptide using tyrosinase on chitosan-coated AuNPs. Peptides were effectively immobilized onto the AuNPs depending on the presence of tyrosine within the sequence, which suggests the DOPA-quinone produced from tyrosine, via tyrosinase, is connected to the chitosan amino group. Although fluorescent emission from the immobilized capase-3 substrate was quenched by AuNPs, fluorescence intensity recovery occurred due to the addition of caspase-3. Thus, we were able to easily prepare functional AuNPs that can be used for a caspase-3 activity assay. Our results indicate that the tyrosinase-mediated peptide link to chitosan-coated particles is a useful technique for preparing functionalized nanoparticles.
3. Pulmonary embolism
Tracy Cardin, Anthony Marinelli Crit Care Nurs Q. 2004 Oct-Dec;27(4):310-22; quiz 323-4. doi: 10.1097/00002727-200410000-00002.
Pulmonary embolism is a commonly suspected but underdiagnosed condition of clinical significance. Preventable deaths continue to occur. We begin this article with an overview of prognosis, clinical evidence, signs and symptoms, and risk factors, followed by an in-depth evaluation of diagnostic techniques and treatment modalities. The greatest improvement in mortality from pulmonary embolism is likely to come from improved and aggressive prevention and prophylaxis by the critical care team.
