[Research progress on the fluorescence resonance energy transfer-based polymer micelles as drug carriers].

Polymer micelles formed by self-assembly of amphiphilic polymers are widely used in drug delivery, gene delivery and biosensors, due to their special hydrophobic core/hydrophilic shell structure and nanoscale. However, the structural stability of polymer micelles can be affected strongly by environmental factors, such as temperature, pH, shear force in the blood and interaction with non-target cells, leading to degradations and drug leakage as drug carriers. Therefore, researches on the structural integrity and in vivo distribution of micelle-based carriers are very important for evaluating their therapeutic effect and clinical feasibility. At present, fluorescence resonance energy transfer (FRET) technology has been widely used in real-time monitoring of aggregation, dissociation and distribution of polymer micelles ( in vitro and in vivo). In this review, the polymer micelles, characteristics of FRET technology, structure and properties of the FRET-polymer micelles are briefly introduced. Then, methods and mechanism for combinations of several commonly used fluorescent probes into polymer micelles structures, and progresses on the stability and distribution studies of FRET-polymer micelles ( in vitro and in vivo) as drug carriers are reviewed, and current challenges of FRET technology and future directions are discussed.

[Preparation and applications of the polymeric micelle/hydrogel nanocomposites as biomaterials].

Polymeric hydrogels have been widely researched as drug delivery systems, wound dressings and tissue engineering scaffolds due to their unique properties such as good biocompatibility, shaping ability and similar properties to extracellular matrix. However, further development of conventional hydrogels for biomedical applications is still limited by their poor mechanical properties and self-healing properties. Currently, nanocomposite hydrogels with excellent properties and customized functions can be obtained by introducing nanoparticles into their network, and different types of nanoparticles, including carbon-based, polymer-based, inorganic-based and metal-based nanoparticle, are commonly used. Nanocomposite hydrogels incorporated with polymeric micelles can not only enhance the mechanical properties, self-healing properties and chemical properties of hydrogels, but also improve the in vivo stability of micelles. Therefore, micelle-hydrogel nanocomposites have been recently considered as promising biomaterials. In this paper, the structure, properties and methods for preparation of the micelle-hydrogel nanocomposite systems are introduced, and their applications in drug delivery, wound treatment and tissue engineering are reviewed, aiming to provide reference for further development and application of the nanocomposites.

The association of endocannabinoid receptor genes (CNR1 and CNR2) polymorphisms with depression: A meta-analysis.

Studies investigating the association between gene variants and depression susceptibility found inconsistent data. The present study aimed to clarify whether CNR1rs1049353, CNR1 AAT triplet repeat, and CNR2rs2501432 polymorphisms confer higher risk for depressive disorder.Literature from PubMed, Medline, Embase, Scopus, Cochrance Library, and Wanfang databases was searched (up to August 20, 2018). Seven case-control studies with various comorbidities were eligible. We targeted CNR single-nucleotide polymorphisms (SNPs) that have been reported by 2 or more studies to be involved in the current meta-analysis, resulting in a final list of 3 SNPs: CNR1rs1049353, CNR1 AAT triplet repeat polymorphism, and CNR2rs2501432. Odds ratios (ORs) and 95% confidence intervals (CIs) for allele and homozygote comparisons, dominant and recessive models, and triplet repeat polymorphism ((AAT)n≥5, ≥5 vs (AAT)n<5, <5 or <5, ≥5) were assessed using a random effect model as measures of association. Heterogeneity among included studies was analyzed using sensitivity test. Publication bias was also explored by Egger and rank correlation test.overall, no significant association was found between depression and CNR1rs1049353 (G vs A: OR [95% CI] = 1.09 [0.61-1.95]; GG vs AA: 1.29 [0.73-2.26]; GG vs GA+AA: 1.10 [0.57-2.10]; GG+GA vs AA: 1.25 [0.72-2.18]; and AAT triplet repeat polymorphism ((AAT)n≥5, ≥5 vs (AAT)n<5, <5 or <5, ≥5): 1.92 [0.59-6.27]. In contrast, a significant association between CNR2rs2501432 and depression was detected, and the ORs and 95% CIs are as follows: allele contrast (OR = 1.39, 95% CI = [1.12-1.72], P = .003); homozygous (OR = 2.19, 95% CI = [1.34-3.59], P = .002); dominant (OR = 1.93,95% CI = [1.23-3.04], P = .005); and recessive (OR = 1.41, 95% CI = [1.04-1.92], P = .03).This meta-analysis revealed that CNR1rs1049353 or AAT triplet repeat polymorphism had no association with susceptibility to depression, while CNR2rs2501432 polymorphism was a remarkable mark for depression patients.