3D-Printed Hybrid Collagen/GelMA Hydrogels for Tissue Engineering Applications

Bioprinting is an emerging technology involved in the fabrication of three-dimensional tissue constructs for the repair and regeneration of various tissues and organs. Collagen, a natural protein found abundantly in the extracellular matrix of several tissues, can be extracted from collagen-rich tissues of animals such as sheep, cows, rats, pigs, horses, birds, and marine animals. However, due to the poor printability of collagen bioinks, biocompatible collagen scaffolds that mimic the extracellular matrix (ECM) are difficult to fabricate using bioprinting techniques. Gelatin methacrylate (GelMA), a semi-synthetic polymer with tunable physical and chemical properties, has been found to be a promising biomaterial in various bioprinting applications. The printability of collagen can be improved by combining it with semi-synthetic polymers such as GelMA to develop hybrid hydrogels. Such hybrid hydrogels printed have also been identified to have enhanced mechanical properties. Hybrid GelMA meshes have not previously been prepared with collagen from ovine sources. This study provides a novel comparison between the properties of hybrid meshes with ovine skin and bovine hide collagen. GelMA (8% w/v) was integrated with three different concentrations (0.5%, 1%, and 2%) of bovine and ovine collagen forming hybrid hydrogels inks that were printed into meshes with enhanced properties. The maximum percentage of collagen suitable for integration with GelMA, forming hybrid hydrogels with a stable degradation rate was 1%. The water-soluble nature of ovine collagen promoted faster degradation of the hybrid meshes, although the structural crosslinking was identified to be higher than bovine hybrid meshes. The 1% bovine collagen hybrid meshes stood out in terms of their stable degradation rates

Comparison of Conventional Pap Smears versus Liquid Based Cytology for Clinicopathological Patterns of Cervical Lesions at a Tertiary Care Centre, Bangalore, India

Introduction: Conventional Pap Smear (CPS) technique has been the mainstay for early detection of cervical cancer. However, its extensive use has not been possible due to the limitations, like presence of obscuring blood and inflammation, reducing its sensitivity markedly. False negativity of CPS is also very high, so Liquid Based Cytology (LBC) was introduced. Aim: To compare cytomorphological patterns, diagnostic utility and adequacy of smears of cervical lesions on CPS and LBC. Materials and Methods: This was a prospective descriptive study, conducted in the Department of Pathology of Dr. B R Ambedkar Medical College and Hospital, Bangalore for 19 months during November 2018 to May 2020 on 250 cases. The samples were taken with cervix-brush. First, a CPS was prepared and was immediately alcohol-fixed. After that the same brush head was rinsed in LBC vial containing methanol. Statistical analysis was done using the Statistical Package for the Social Sciences 22.0 (SPSS) and R environment 3.2.2 for data analysis. Results: Most of the patients were in the fourth decade of life and 160 cases (64%) presented as white discharge per vaginum. Total 231 (92.4%) smears were satisfactory on CPS and 233 (93.2%) smears on LBC. The number of Low grade Squamous Intraepithelial Lesions (LSIL) increased from 4 cases (1.6%) in CPS to 6 cases (2.4%) in LBC in this study. Rate of detection of High grade Squamous Intraepithelial Lesion (HSIL) was more with LBC (11 cases, 4.4%) compared to that of CPS (7 cases, 2.8%). It was seen that in this study, sensitivity and specificity of LBC was higher than CPS in detecting LSIL and HSIL, except for the specificity of CPS, which was more than LBC in detecting LSIL. The present study showed overall sensitivity of 77.1% in CPS and 94.3% in LBC and specificity of 97.2% and 100% in CPS and LBC, respectively. The p-value calculated was <0.001, which was highly significant. Conclusion: The LBC technique showed clear background, well preserved cytomorphological details, removal of extra mucus, blood and inflammatory cell infiltrate as compared to CPS technique. Atypical cells or abnormal cells were seen better and were detected more by LBC as compared to CPS