Ultrasonic atomizer based development of pH sensor for real time analysis
SCIENTIFIC REPORTS
Authors: Pandey, Gaurav; Choudhary, Sandeep; Chaudhari, Rashmi; Joshi, Abhijeet
Abstract
Fluorescent pH biosensors have gained importance owing to their low cost utilization in real time monitoring of biological and food samples in comparison to conventional pH meters. The research reports a novel method of ultrasonic atomization for developing a fluorescent pH sensor for real-time analysis made of Fluorescein isothiocyanate (FITC)-dextran/FITC-dextran-Tris (2, 2 ' -bipyridyl) dichlororuthenium (II) hexahydrate as indicator and reference fluorophores, respectively. The process of ultrasonic atomization ensures formation of monodisperse dye immobilized alginate microspheres ensuring efficient pH sensing. The developed biosensor was tested on milk samples, which has a short life span and shows a significant fall in pH with time due to microbial spoilage. The proposed biosensor showed a linear range of pH 4-8 (R-2 between 0.96-0.99 for different single/dual fluorophore biosensors) which suitably cover the pH of milk during the entire storage period and spoilage. The % recovery for predicted pH falls between 90-110% compared against standard pH meter, indicating a good accuracy of estimation and low turnaround time (10 min). Thus, real-time monitoring using fluorescent pH biosensor for milk samples may profoundly improve the economics of losses occurring in processing and storage with capability of in-package continuous quality assessment.
Cytotoxicity study of the interleukin-12-expressing recombinant Newcastle disease virus strain, rAF-IL12, towards CT26 colon cancer cells in vitro and in vivo
CANCER CELL INTERNATIONAL
Authors: Najmuddin, Syed Umar Faruq Syed; Amin, Zahiah Mohamed; Tan, Sheau Wei; Yeap, Swee Keong; Kalyanasundram, Jeevanathan; Ani, Muhamad Alhapis Che; Veerakumarasivam, Abhimanyu; Chan, Soon Choy; Chia, Suet Lin; Yusoff, Khatijah; Alitheen, Noorjahan Banu
Abstract
Background Oncolytic viruses have emerged as an alternative therapeutic modality for cancer as they can replicate specifically in tumour cells and induce toxic effects leading to apoptosis. Despite the great potentials and promising results shown in multiple studies, it appears that their efficacy is still moderate and deemed as not sufficient in clinical studies. In addressing this issue, genetic/molecular engineering approach has paved its way to improve the therapeutic efficacy as observed in the case of herpes simplex virus (HSV) expressing granulocyte-macrophage colony-stimulating factor (GM-CSF). This study aimed to explore the cytotoxicity effects of recombinant NDV strain AF2240-i expressing interleukin-12 (rAF-IL12) against CT26 colon cancer cells. Methods The cytotoxicity effect of rAF-IL12 against CT26 colon cancer cell line was determined by MTT assay. Based on the IC(50)value from the anti-proliferative assay, further downward assays such as Annexin V FITC and cell cycle progression were carried out and measured by flow cytometry. Then, the in vivo study was conducted where the rAF-IL12 viral injections were given at the intra-tumoral site of the CT26 tumour-burden mice. At the end of the experiment, serum biochemical, T cell immunophenotyping, serum cytokine, histopathology of tumour and organ section, TUNEL assay, and Nanostring gene expression analysis were performed. Results The rAF-IL12 induced apoptosis of CT26 colon cancer cells in vitro as revealed in the Annexin V FITC analysis and also arrested the cancer cells progression at G(1)phase of the cell cycle analysis. On the other hand, the rAF-IL12 significantly (p < 0.05) inhibited the growth of CT26 tumour in Balb/c mice and had regulated the immune system by increasing the level of CD4 + , CD8 + , IL-2, IL-12, and IFN-gamma. Furthermore, the expression level of apoptosis-related genes (bax and p53) was up-regulated as a result of the rAF-IL12 treatment. Additionally, the rAF-IL12 had also down-regulated the expression level of KRAS, BRAF, MAPK1, Notch1, CCL2, and VEGF oncogenes. Besides, rAF-IL12 intra-tumoral delivery was considered safe and not hazardous to the host as evidenced in pathophysiology of the normal tissues and organs of the mice as well as from the serum biochemistry profile of liver and kidney. Conclusions These results indicated that rAF-IL12 had better anti-tumoral and cytotoxicity effects compared to its parental wild-type, AF2240-i in combatting the CT26 colon cancer model.