eMedicine创建于1996年，由近万名临床医师作为作者或编辑参与此临床医学知识库的建设，其中编辑均是来自美国哈佛、耶鲁、斯坦福、芝加哥、德克萨斯、加州大学等各分校医学院的教授或副教授。

eMedicine

The microfabrication technologies of the semiconductor industry have made it possible to integrate increasingly complex electronic and mechanical functions, providing us with ever smaller, cheaper and smarter sensors and devices. These technologies have also spawned microfluidics systems for containing and controlling fluid at the micrometre scale, where the increasing importance of viscosity and surface tension profoundly affects fluid behaviour. It is this confluence of available microscale engineering and scale-dependence of fluid behaviour that has revolutionized our ability to precisely control fluid/fluid interfaces for use in fields ranging from materials processing and analytical chemistry to biology and medicine.

Controlled microfluidic interfaces

Stimuli-responsive LbL capsules and nanoshells for drug delivery.

Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

/pdf/triggered-release-from-polymer-capsules-3iipnngeta.pdf

Triggered Release from Polymer Capsules

Background 
Metabolomics is the rapidly evolving field of the comprehensive measurement of ideally all endogenous metabolites in a biological fluid. However, no single analytic technique covers the entire spectrum of the human metabolome. Here we present results from a multiplatform study, in which we investigate what kind of results can presently be obtained in the field of diabetes research when combining metabolomics data collected on a complementary set of analytical platforms in the framework of an epidemiological study.


Methodology/Principal Findings 
40 individuals with self-reported diabetes and 60 controls (male, over 54 years) were randomly selected from the participants of the population-based KORA (Cooperative Health Research in the Region of Augsburg) study, representing an extensively phenotyped sample of the general German population. Concentrations of over 420 unique small molecules were determined in overnight-fasting blood using three different techniques, covering nuclear magnetic resonance and tandem mass spectrometry. Known biomarkers of diabetes could be replicated by this multiple metabolomic platform approach, including sugar metabolites (1,5-anhydroglucoitol), ketone bodies (3-hydroxybutyrate), and branched chain amino acids. In some cases, diabetes-related medication can be detected (pioglitazone, salicylic acid).


Conclusions/Significance 
Our study depicts the promising potential of metabolomics in diabetes research by identification of a series of known and also novel, deregulated metabolites that associate with diabetes. Key observations include perturbations of metabolic pathways linked to kidney dysfunction (3-indoxyl sulfate), lipid metabolism (glycerophospholipids, free fatty acids), and interaction with the gut microflora (bile acids). Our study suggests that metabolic markers hold the potential to detect diabetes-related complications already under sub-clinical conditions in the general population.

/pdf/metabolic-footprint-of-diabetes-a-multiplatform-metabolomics-4lmbarm42e.pdf

Metabolic footprint of diabetes: a multiplatform metabolomics study in an epidemiological setting.

Crystallization of L-cystine is a critical step in the pathogenesis of cystine kidney stones. Treatments for this disease are somewhat effective but often lead to adverse side effects. Real-time in situ atomic force microscopy (AFM) reveals that L-cystine dimethylester (L-CDME) and L-cystine methylester (L-CME) dramatically reduce the growth velocity of the six symmetry-equivalent {100} steps because of specific binding at the crystal surface, which frustrates the attachment of L-cystine molecules. L-CDME and L-CME produce l-cystine crystals with different habits that reveal distinct binding modes at the crystal surfaces. The AFM observations are mirrored by reduced crystal yield and crystal size in the presence of L-CDME and L-CME, collectively suggesting a new pathway to the prevention of L-cystine stones by rational design of crystal growth inhibitors.

/pdf/crystal-growth-inhibitors-for-the-prevention-of-l-cystine-4eb4m5yizo.pdf

Crystal Growth Inhibitors for the Prevention of l-Cystine Kidney Stones Through Molecular Design

pH controlled permeability of lipid/protein biomimetic microcapsules

Our recent work on the fabrication of microcapsules comprised of human serum albumin (HSA) and L-α-dimyristoylphosphatitic acid (DMPA) by means of stepwise adsorption of HSA and DMPA on fluid droplet surfaces or charged colloids and subsequent dissolution of the cores is reviewed. The lipid self-assembles as a bilayer on the protein surface and the completed microcapsule serves as a biomimetic membrane model. The DMPA/HSA microcapsules have good biocompatibility and the potential for the insertion of recognition units in the lipid bilayers. The structure and properties of the lipid/protein microcapsules are described and their potential for applications in sustained drug release are introduced.

Molecular assembly of biomimetic microcapsules

Human serum albumin (HSA) and L-alpha-dimyristoylphosphatidic acid (DMPA) were applied as a pair to encapsulate ibuprofen microcrystals by means of a technique based on the layer-by-layer (LbL) assembly of oppositely charged species, for the purpose of controlling drug release. The successful adsorption of HSA and DMPA multilayers onto ibuprofen crystals was confirmed by optical microscopy. The drug release process, in a solution of pH 7.4, was monitored by optical microscopy and UV spectroscopy. The results revealed that the rate of release of ibuprofen from HSA/DMPA microcapsules decreased as the capsule wall thickness and drug crystal size increased, indicating that the permeability of the microcapsules can be controlled by simply varying the number of HSA/DMPA deposition cycles.

Zhihua An

Papers

Crystal Growth Inhibitors for the Prevention of l-Cystine Kidney Stones Through Molecular Design

pH controlled permeability of lipid/protein biomimetic microcapsules

Molecular assembly of biomimetic microcapsules

Molecular assembly of biomimetic microcapsules

Self-assembly of human serum albumin (HSA) and L-alpha-dimyristoylphosphatidic acid (DMPA) microcapsules for controlled drug release.