Biology subjects

Yadavalli, V. K.

Publications and source records attributed to Yadavalli, V. K..

3 recordsLinked to original sources

bioRxiv2024

Enhancing the versatility of photocrosslinkable silk fibroin using an eco-friendly solvent

Silk fibroin (SF), known for its biocompatibility and versatility, has been widely studied in tissue engineering and biomedical devices. The modification of silk fibroin with photoreactive groups has been used to create novel biomaterials that undergo a liquid-to-solid transition upon exposure to light, enabling precise control over structure formation, pore geometry, and degradation. This advancement of photofibroin (PF) has been shown for the biofabrication of hydrogels, 3D scaffolds, and micro-patterned surfaces suitable for biomedical applications, including tissue scaffolds and bioelectronics. Here, we present a further improvement using a water based ternary solvent of calcium chloride-ethanol-water (Ajisawa reagent (AR)), to dissolve photofibroin, offering a sustainable alternative to previously used organic solvents. PF in AR is shown to be compatible with various light-based manufacturing techniques including soft lithography, photolithography, and 3D printing, enabling the fabrication of multiscale structures with high fidelity. The gels formed demonstrate excellent cytocompatibility, supporting cell adhesion and growth without additional coatings, making them ideal for regenerative medicine. The integration of conductive polymers, such as PEDOT:PSS as a 3D printable conducting gel opens possibilities for bioelectronics. The research represents a significant step forward in employing the versatile photofibroin as a sustainable, high-performance biomaterial for diverse applications.

bioengineering↗

bioRxiv2020

Open source software tool for the automated detection and characterization of epithelial cells from trace biological samples

This paper presents a strategy for an unsupervised workflow for identifying epithelial cells in microscopic images and characterizing their morphological and/or optical properties. The proposed method can be used on cells that have been stained with fluorescent dyes and imaged using conventional optical microscopes. The workflow was tested on cell populations that were imaged directly on touch/contact surfaces and stained with nucleic acid dyes to visualize genetic content. Our results show that this approach could be a useful strategy for characterizing differences in staining efficiency and/or morphological properties of individual cells or aggregate populations within a biological sample. Further, they can potentially reduce the laborious nature of microscopic analysis and increase throughput and reproducibility of similar studies.

cell biology↗

bioRxiv2019

Testing Hormone-specific Antibody Probes for Presumptive Detection and Separation of Contributor Cell Populations in Trace DNA Mixtures

"Touch" or trace DNA evidence represent a significant proportion of samples analyzed by forensic science laboratories. Because these samples frequently contain multiple contributors and are often challenging to analyze due to low DNA concentrations and frequent degradation, front end techniques to simplify the mixture prior to DNA profiling could significantly impact case processing and enhance success rates. The goal of this study was to investigate whether targeting hormone molecules within the cell with antibody probes could be used to selectively label and then physically isolate contributor cell populations in trace biological samples. The separation of male and female cells into distinct fractions could reduce the complexity of the mixture prior to DNA profiling. To accomplish this, we first tested the specificity of fluorescently labelled anti-testosterone and anti-dihydrotestosterone antibody probes to epidermal cells from both male and female individuals. Results show that male and female cell populations can be effectively labeled using anti-testosterone and anti-dihydrotestosterone antibody probes and that distinct differences in binding efficiency and resulting median fluorescence of cell populations were observed between several individuals. These differences were then used to design sorting criteria for physically isolating each cell population in two-person epidermal cell mixtures using fluorescence activated cell sorting (FACS). DNA profiling of separated fractions in combination with probabilistic modeling demonstrated that some cell mixtures could be enriched for one contributor in separated cell fractions and yielded statistically more discriminating profiles compared to those generated from the original mixtures. Other mixtures tested showed less evidence of effective cell separation possibly due to a number of factors including imbalance of contributor DNA ratio, intra-sex variation of antibody binding efficiency, and contributions of extracellular or cell-free DNA in the mixture sample. Screening and separation of trace DNA samples with this approach may be presumptive and ultimately constrained by specific parameters of the original mixture, however, antibody binding optimization may mitigate some of these influences.

molecular biology↗