Prevention of C. Albicans Biofilms by Beta-Peptide Release From Thin Films

描述（由申请人提供）：白色念珠菌是从人类分离的最常见的真菌病原体，是医院获得性感染的主要原因。系统性念珠菌病是一种通常致命的疾病，通常与留置医疗器械表面形成的白色念珠菌生物膜有关。我们项目的目标是开发一种新的策略来防止白色念珠菌在导管上形成生物膜，从而降低高危患者念珠菌的发病率。在先前的工作中，PI发现，与哺乳动物细胞相比，阳离子，氨基酸的两亲性低聚物（称为肽）可以对白色念珠菌表现出高水平的特异性活性。这些¿-肽是基于与天然抗菌肽的结构相似性而设计的，天然抗菌肽在与细胞膜结合时通常折叠成两亲性阳离子螺旋。然而，与a肽抗菌肽相比，-肽可以被设计成具有关键优势，包括生理pH值和离子强度的活性，更大的结构稳定性，以及对蛋白水解降解的抗性。在这里，我们将设计活性和选择性的螺旋肽化合物，并评估它们在体外和体内阻止白色念珠菌生物膜形成的能力。此外，我们将研究混合a/¿-肽的特定抗真菌活性，这些肽也折叠成两亲性螺旋，并允许在¿-肽的结构之外进行调节。为了促进抗真菌肽和抗真菌肽从医疗器械表面的传递，我们将设计聚电解质多层（PEM）薄膜，该薄膜结合并以相关的速率释放肽，以防止导管应用中生物膜的形成。我们将评估膜厚度、膜交联、肽结构和化学性质如何影响释放速率。抗真菌肽和抗真菌肽抑制白色念珠菌生物膜形成的能力将在体外通过测定生物膜形成速率和生物膜结构来量化。优化后的肽和释放策略将在大鼠中心静脉导管模型中进行体内评估。综上所述，这些结果将验证导管上PEM膜上传递的-和-肽寡聚物将抑制白色念珠菌生物膜的形成，并可能为预防器械相关念珠菌病建立新的范例。

DESCRIPTION (provided by applicant): Candida albicans is the most common fungal pathogen isolated from humans and is a leading cause of hospital-acquired infections. Systemic candidemia, an often fatal disease, is typically associated with C. albicans biofilms formed on the surface of indwelling medical devices. The goal of our project is to develop a novel strategy to prevent C. albicans biofilm formation on catheters, and to thereby reduce the incidence of candidemia in high-risk patients. In prior work the PI identified that cationic, amphiphilic oligomers of ¿-amino acids (called ¿-peptides) can exhibit high levels of specific activity against C. albicans as compared to mammalian cells. These ¿-peptides were designed based on structural similarity to natural antimicrobial peptides, which typically fold into amphiphilic cationic helices when associated with cellular membranes. However, ¿-peptides can be designed to possess key advantages over a-peptide antimicrobial peptides including activity at physiologic pH and ionic strength, greater structural stability, and resistance to proteolytic degradation. Here, we will design active and selective helical -peptides compounds and assess their ability to prevent C. albicans biofilm formation in vitro and in vivo. Additionally, we will investigate the specific antifungal activity of mixed a/¿-peptides, which also fold into amphiphilic helices, and permit regulation of structure beyond that of ¿-peptides. To facilitate delivery of antifungal ¿- and a/¿-peptides from the surface of medical devices we will design polyelectrolyte multilayer (PEM) films that incorporate and release the peptides at rates relevant for prevention of biofilm formation in vivo in catheter applications. We will assess how film thickness, film crosslinking, and peptide structures and chemical properties influence rate of release. The ability of antifungal ¿- and a/¿-peptides to inhibit C. albicans biofilm formation will be quantified in vitro by determining biofilm formation rate and biofilm structure on substrates coated with peptide-incorporated PEM films. Optimized peptides and release strategies will then be assessed in vivo using a rat central venous catheter model. Together these results will test the prediction that delivery of ¿- and a/¿-peptide oligomers from a PEM film on a catheter will inhibit C. albicans biofilm formation, and may establish a new paradigm for prevention of device-associated candidemia.