ABSTRACT
Stents or stent-grafts are often functionalized with films to enhance cell/surface interactions and improve endothelialization. However, continuous film coatings by common surface modification tactics may preclude cells from migrating along the thickness direction and may change the physical characteristics of stent-grafts. Here, polydopamine nanoparticles (PDA-NPs) are attached on braided stent-grafts tightly, forming a nanostructure on microfilaments. They also serve as the anchor for bioactive REDV peptide immobilization to promote endothelia cells (ECs) activities. The results show that braided stent-grafts decorated with PDA-NPs and REDV demonstrate an excellent endothelialization performance and hemocompatibility due to the micro/nanostructure formed and REDV affinity to ECs. The physical properties of stent-grafts are also not compromised. A potential surface modification strategy for scaffold applications is illustrated.
ABSTRACT
MicroRNA (miRNA) in urine has been considered as a potential biomarker for early-stage diagnosis of multiple diseases like urinary system cancer, kidney injury and diabetes, owing to their many demonstrated advantages including long-term stability and noninvasiveness. However, the traditional enrichment and extraction processes of miRNAs from urine are cumbersome and tedious due to the low concentration and multiple carriers of miRNAs. Herein, we present a novel method to collect low concentrations of miRNAs from dilute solutions such as urine and cell culture medium. 10-nm core sized magnetic nanoparticles with carboxylic acid coating can adsorb low-concentration proteins, and form protein corona which makes them easy to aggregate and precipitate for subsequent isolation. In urine and cell culture medium, these nanoparticles can aggregate with proteins, including miRNAs-associated protein Argonaute 2 and microvesicle-related proteins, to form precipitates, so that miRNAs can be easily extracted from pellets by small amount of lysis buffer for subsequent analysis such as real-time PCR. Our method provides a facile way to enrich miRNAs from biofluids without the need of ultracentrifugation and immunoprecipitations, bringing remarkable convenience to miRNAs-based biomarker research.
ABSTRACT
The accumulation and formation of ß-amyloid (Aß) plaques in the brain are distinctive pathological hallmarks of Alzheimer's disease (AD). Designing nanoparticle (NP) contrast agents capable of binding with Aß highly selectively can potentially facilitate early detection of AD. However, a significant obstacle is the blood brain barrier (BBB), which can preclude the entrance of NPs into the brain for Aß binding. In this work, bovine serum albumin (BSA) coated NPs are decorated with sialic acid (NP-BSAx -Sia) to overcome the challenges in Aß imaging in vivo. The NP-BSAx -Sia is biocompatible with high magnetic relaxivities, suggesting that they are suitable contrast agents for magnetic resonance imaging (MRI). The NP-BSAx -Sia binds with Aß in a sialic acid dependent manner with high selectivities toward Aß deposited on brains and cross the BBB in an in vitro model. The abilities of these NPs to detect Aß in vivo in human AD transgenic mice by MRI are evaluated without the need to coinject mannitol to increase BBB permeability. T2 *-weighted MRI shows that Aß plaques in mouse brains can be detected as aided by NP-BSAx -Sia, which is confirmed by histological analysis. Thus, NP-BSAx -Sia is a promising new tool for noninvasive in vivo detection of Aß plaques.
