Dataset Information

Automated and adaptable quantification of cellular alignment from microscopic images for tissue engineering applications.

ABSTRACT: Cellular alignment plays a critical role in functional, physical, and biological characteristics of many tissue types, such as muscle, tendon, nerve, and cornea. Current efforts toward regeneration of these tissues include replicating the cellular microenvironment by developing biomaterials that facilitate cellular alignment. To assess the functional effectiveness of the engineered microenvironments, one essential criterion is quantification of cellular alignment. Therefore, there is a need for rapid, accurate, and adaptable methodologies to quantify cellular alignment for tissue engineering applications. To address this need, we developed an automated method, binarization-based extraction of alignment score (BEAS), to determine cell orientation distribution in a wide variety of microscopic images. This method combines a sequenced application of median and band-pass filters, locally adaptive thresholding approaches and image processing techniques. Cellular alignment score is obtained by applying a robust scoring algorithm to the orientation distribution. We validated the BEAS method by comparing the results with the existing approaches reported in literature (i.e., manual, radial fast Fourier transform-radial sum, and gradient based approaches). Validation results indicated that the BEAS method resulted in statistically comparable alignment scores with the manual method (coefficient of determination R(2)=0.92). Therefore, the BEAS method introduced in this study could enable accurate, convenient, and adaptable evaluation of engineered tissue constructs and biomaterials in terms of cellular alignment and organization.

SUBMITTER: Xu F

PROVIDER: S-EPMC3103056 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Automated and adaptable quantification of cellular alignment from microscopic images for tissue engineering applications.

Xu Feng F Beyazoglu Turker T Hefner Evan E Gurkan Umut Atakan UA Demirci Utkan U

Tissue engineering. Part C, Methods 20110418 6

Cellular alignment plays a critical role in functional, physical, and biological characteristics of many tissue types, such as muscle, tendon, nerve, and cornea. Current efforts toward regeneration of these tissues include replicating the cellular microenvironment by developing biomaterials that facilitate cellular alignment. To assess the functional effectiveness of the engineered microenvironments, one essential criterion is quantification of cellular alignment. Therefore, there is a need for ...[more]

PMID: 21370940

Similar Datasets

Project description:BackgroundMalaria is a serious infectious disease. According to the World Health Organization, it is responsible for nearly one million deaths each year. There are various techniques to diagnose malaria of which manual microscopy is considered to be the gold standard. However due to the number of steps required in manual assessment, this diagnostic method is time consuming (leading to late diagnosis) and prone to human error (leading to erroneous diagnosis), even in experienced hands. The focus of this study is to develop a robust, unsupervised and sensitive malaria screening technique with low material cost and one that has an advantage over other techniques in that it minimizes human reliance and is, therefore, more consistent in applying diagnostic criteria.MethodA method based on digital image processing of Giemsa-stained thin smear image is developed to facilitate the diagnostic process. The diagnosis procedure is divided into two parts; enumeration and identification. The image-based method presented here is designed to automate the process of enumeration and identification; with the main advantage being its ability to carry out the diagnosis in an unsupervised manner and yet have high sensitivity and thus reducing cases of false negatives.ResultsThe image based method is tested over more than 500 images from two independent laboratories. The aim is to distinguish between positive and negative cases of malaria using thin smear blood slide images. Due to the unsupervised nature of method it requires minimal human intervention thus speeding up the whole process of diagnosis. Overall sensitivity to capture cases of malaria is 100% and specificity ranges from 50-88% for all species of malaria parasites.ConclusionImage based screening method will speed up the whole process of diagnosis and is more advantageous over laboratory procedures that are prone to errors and where pathological expertise is minimal. Further this method provides a consistent and robust way of generating the parasite clearance curves.

Project description:Cartilage tissue engineering strategies often rely on hydrogels with fixed covalent crosslinks for chondrocyte encapsulation, yet the resulting material properties are largely elastic and can impede matrix deposition. To address this limitation, hydrazone crosslinked poly(ethylene glycol) hydrogels were formulated to achieve tunable viscoelastic properties and to study how chondrocyte proliferation and matrix deposition vary with the time-dependent material properties of covalent adaptable networks. Hydrazone equilibrium differences were leveraged to produce average stress relaxation times from hours (4.01 × 103 s) to months (2.78 × 106 s) by varying the percentage of alkyl-hydrazone (aHz) and benzyl-hydrazone (bHz) crosslinks. Swelling behavior and degradation associated with adaptability were characterized to quantify temporal network changes that can influence the behavior of encapsulated chondrocytes. After four weeks, mass swelling ratios varied from 36 ± 3 to 17 ± 0.4 and polymer retention ranged from 46 ± 4% to 92 ± 5%, with higher aHz content leading to loss of network connectivity with time. Hydrogels were formulated near the Flory-Stockmayer bHz percolation threshold (17% bHz) to investigate chondrocyte response to distinct levels of covalent architecture adaptability. Four weeks post-encapsulation, formulations with average relaxation times of 3 days (2.6 × 105s) revealed increased cellularity and an interconnected articular cartilage-specific matrix. Chondrocytes embedded in this adaptable formulation (22% bHz) deposited 190 ± 30% more collagen and 140 ± 20% more sulfated glycosaminoglycans compared to the 100% bHz control, which constrained matrix deposition to pericellular space. Collectively, these findings indicate that incorporating highly adaptable aHz crosslinks enhanced regenerative outcomes. However, connected networks containing more stable bHz bonds were required to achieve the highest quality neocartilaginous tissue. STATEMENT OF SIGNIFICANCE: Covalently crosslinked hydrogels provide robust mechanical support for cartilage tissue engineering applications in articulating joints. However, these materials traditionally demonstrate purely elastic responses to deformation despite the dynamic viscoelastic properties of native cartilage tissue. Here, we present hydrazone poly(ethylene glycol) hydrogels with tunable viscoelastic properties and study covalent adaptable networks for cartilage tissue engineering. Using hydrazone equilibrium and Flory-Stockmayer theory we identified average relaxation times leading to enhanced regenerative outcomes and showed that extracellular matrix deposition was biphasic as a function of the hydrazone covalent adaptability. We also showed that the incorporation of highly adaptable covalent crosslinks could improve cellularity of neotissue, but that a percolating network of more stable bonds was required to maintain scaffold integrity and form the highest quality neocartilaginous tissue.

Dataset Information

Automated and adaptable quantification of cellular alignment from microscopic images for tissue engineering applications.

Publications

Automated and adaptable quantification of cellular alignment from microscopic images for tissue engineering applications.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets