Cellular Microenvironments

However, IHC as a practical method continues to evolve with increasing demands for standardization, and for true quantification of protein analytes by weight, in the context of their cellular microenvironment. Further studies combining proteomics by mass spectrometry and IHC are likely to lead to the refinement of both methods in the analysis of FFPE tissues. The end result may be the creation of a broader field that defines and quantifies protein expression at a cellular level, incorporating the advantages of the wide spectrum of proteins demonstrable by mass spectrometry and the precise localization offered by IHC. 

We currently established cultural system (amphycultural diffusion capsules) that allowed for conditions favorable for stem cell expansion in vitro. Many cell types and culture protocols and their combination with cytokines, growth factors, feeder layers can be implemented with ADC. Capsules are characterized by high perfusion rates that ensure that allow dilution of inhibitory autocrine factors and support long-term cell expansion. We have shown that ADC in vitro provides optimal cellular microenvironment that supports long term hematopoiesis (Bilko et al. 2005). 

It is evident that a single electron transfer photoproduct is transformed into a doubly reduced charge relay in two phase systems. The primary processes in the natural photosynthetic apparatus involve single electron transfer reactions that proceed in hydrophobic-hydrophilic cellular microenvironment. Thus, we suggest similar induced disproportionation mechanisms as possible routes for the formation of multi-electron charge relays, effective in the fixation of CO2 or N2. 

In this chapter we introduce various techniques for fabricating miniature cell culture devices and cell-based biosensors, provide examples of human and animal cells immobilized on the chip devices, and explain different approaches to pattern multiple types of cells on one device. The application of nano and micro techniques in precise control over the cellular microenvironment is discussed. Selective cell-based biosensors are described later in the chapter. Finally, we conclude that these novel cell culture systems, coupled with predictions from in silico mathematical modeling, can potentially improve predictions of human clinical responses and enable better understanding of toxicological mechanisms. 

In vivo, living cells constantly communicate with their surroundings. The interaction between the cells and the extracellular microenvironment regulates cell behavior. With nano and microfabrication techniques, researchers are now able to control cell functions and responses through precise manipulation over the physical and chemical environment around a cell, such as the surface chemical composition and topology of the substrate, the medium composition, and the cellular microenvironment [69],... 

Sun Y, Chen CS, Fu J (2012) Forcing stem cells to behave a biophysical perspective of the cellular microenvironment. Annu Rev Biophys 41 519-542... 

The optical tweezers technique has been a powerful tool for biological application. We believe that precise control of the cellular microenvironment and single-cell analysis provide opportunities to predict the effects of external stimuli including cell-cell, cell-ECM and cell-soluble factor interaction on the cell behavior and fate, which are link to revealing the internal cellular signaling system. There still exists a broad distribution of cell responses even by single-cell analysis. Researchers need to improve and develop the technique to one utilizable for a precise analysis. The... 

Pnnzel M, Liu D, Zhang T, et al. (2003). The symmetry of initial divisions of human hematopoietic progenitors is altered only by the cellular microenvironment. Exp. Hematol. 31 339-347. 

Silver, L, Cellular microenvironment in healing and non-healing wounds, (4), 50-66. 

Because two-hybrid systems are in vivo assays, they offer advantages over in vitro biophysical or biochemical methods for the study of protein interactions. Indeed, some PPIs are too weak and/or transient to be detected in vitro, and some of these interactions require specific PTMs of the proteins or specific co-factors in the cellular microenvironment. Hence, it is advantageous to determine protein interaction networks in mammalian cells using mammalian two-hybrid assays as compared to the more commonly used YTH assays (Lee and Lee 2004). Until recently, high-throughput analyses of protein interactions were typically performed in yeast, and putative interactions were confirmed afterwards in mammalian two-hybrid assays on a gene-by-gene basis (Tavernier et al. 2002). 

Several important cell types are sensitive to the electrical characteristics of the cellular microenvironment. Neurons, cardiac myocytes, and retinal cells all generate and can be stimulated with electrical impulses. Because of the importance of these cell types, various methods have been devised to record or stimulate electrical activity within cells cultured in vitro. Traditionally, the electrical activity of cells has been recorded or stimulated by simply placing electrodes in the... 

Microfabrication technology has provided a plethora of tools and methods to engineer the position and microenvironment of cells in vitro. The unprecedented level of control over the mechanical, chemical, and electrical nature of the cellular microenvironment allows investigation of questions not addressable with conventional tools and methods. The unique insight into normal and abnormal cell behavior afforded by microfabricated tools and methods may one day lead to cures for injuries and diseases, and the ability to direct cell growth and behavior for tissue engineering or industrial applications. 

Chemical and Topographical Patterning to Enhance the Cellular Microenvironment 452... 

---