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1、基于微胶囊的光学生物传感器Microcapsules as optical biosensors,Introduction,color-changing particles reside primarily in the dermisrespond to changes in interstitial fluid compositionmeasurable shifts in their optical properties.external optical device pass light into the skincollectreflected or emitted lightperf
2、orm analysis to report interstitial composition to the patient in a continuous or spot fashion,smart tattoo,Examples of this concept:fluorescent microspheres/capsules,hollow fiber membranes encapsulating sensing chemistry,and polymeric slabs doped with fluorescent reagents.the target species are abl
3、e to freely diffuse into the container,while permanently compartmentalizing the sensing reagents,The key to making this approach viable：engineer implantable materials,sensitivity,operational stability,and biocompatibility for long-term use,Encapsulation within polyelectrolyte multilayer capsules,Nan
4、o-engineered microcapsule carriers is an effective means of encapsulating sensing reagents.Different approaches to entrap optical sensing assays:various types of microvesicles,including liposomes,polymersomes,and polyelectrolyte microcapsules.Polyelectrolyte microcapsules are formed by depositing al
5、ternating layers of charged polymers onto sacrificial templates using the layer-by-layer(LbL)nanoscale self assembly process,which is followed by the removal of the template via chemical treatment.,layer-by-layer(LbL)nanoscale self-assembly process allows for an even wider assortment of candidate ma
6、terials.,The goal of encapsulation is to trap the sensing reagents behind a semi-permeable Barrier.The sensor chemistry must be trapped in sufficient quantity for the optical response to be measured.,Three principal methods:Precipitation,adsorption/absorption,diffusion,1.Diffusion,2.adsorption/absor
7、ption,Advantage:virtually any removable template can be usedDisadvantages:low loading efficiency,requirement to use materials that can be induced to alter pore size,effects encapsulated species,Advantage:allows use of any polymers amenable to the LbL assembly methodDisadvantages:loss of adsorbed/abs
8、orbed molecules during the LbL process,Examples：,PLL/PGA multilayer films on mesoporous silica(MS)spheres,3.Precipitation,Advantage:high loading efficiencies,minimal concern over denaturation or other damage to sensing reagents,entrapped molecules remain stably entrapped during the LbL processDisadv
9、antages:prepare templates each time encapsulation is performed,size distribution of coprecipitated particles is changed,large amounts of sensing reagents used in the coprecipitation process.,Biosensors using PEM capsules,Examples：,nano-engineered glucose sensor microcapsules based on glucose/galacto
10、se-binding protein,Difficult challenges,Further work,1 Mike McShane,Dustin Ritter,“Microcapsules as optical biosensors”,Journal of Materials Chemistry,20(2010)818981932 Aimin Yu,Ian R.Gentle,Gao Qing(Max)Lu,“Biocompatible polypeptide microcapsules via templating mesoporous silica spheres”,Journal of
11、 Colloid and Interface Science 333(2009)341343 Tania Saxla,Faaizah Khan,Daniel R.Matthews,Zheng-Liang Zhi,Olaf Rolinski,Simon Ameer-Beg,John Pickup,“Fluorescence lifetime spectroscopy and imaging of nano-engineered glucose sensor microcapsules based on glucose/galactose-binding protein”,Biosensors and Bioelectronics,24(2009)322932344 C.E.Mora-Huertas,H.Fessi,A.Elaissari,“Polymer-based nanocapsules for drug delivery”,International Journal of Pharmaceutics 385(2010)113142,References,Thank you!,
