Modulation of 3D Bioprintability in Polysaccharide Bioink by Bioglass Nanoparticles and Multiple Metal Ions for Tissue Engineering.

BACKGROUND: Bioglasses are used in applications related to bone rehabilitation and repair. The mechanical and bioactive properties of polysaccharides like alginate and agarose can be modulated or improved using bioglass nanoparticles. Further essential metal ions used as crosslinker have the potential to supplement cultured cells for better growth and proliferation. METHOD: In this study, the alginate bioink is modulated for fabrication of tissue engineering scaffolds by extrusion-based 3D bioprinting using agarose, bioglass nanoparticles and combination of essential trace elements such as iron, zinc, and copper. Homogeneous bioink was obtained by in situ mixing and bioprinting of its components with twin screw extruder (TSE) based 3D bioprinting, and then distribution of metal ions was induced through post-printing diffusion of metal ions in the printed scaffolds. The mechanical and 3d bioprinting properties, microscopic structure, biocompatibility of the crosslinked alginate/agarose hydrogels were analyzed for different concentrations of bioglass. The adipose derived mesenchymal stem cells (ADMSC) and osteoblast cells (MC3T3) were used to evaluate this hydrogel's biological performances. RESULTS: The porosity of hydrogels significantly improves with the incorporation of the bioglass. More bioglass concentration results in improved mechanical (compressive, dynamic, and cyclic) and 3D bioprinting properties. Cell growth and extracellular matrix are also enhanced with bioglass concentration. CONCLUSION: For bioprinting of the bioinks, the advanced TSE head was attached to 3D bioprinter and in situ fabrication of cell encapsulated scaffold was obtained with optimized composition considering minimal effects on cell damage. Fabricated bioinks demonstrate a biocompatible and noncytotoxic scaffold for culturing MC3T3 and ADMSC, while bioglass controls the cellular behaviors such as cell growth and extracellular matrix formation.

Impact of digital boards on hand and neck muscle activity during online teaching process.

Academicians across the globe due to Covid 19 shifted to online teaching as a mainstream method by replacing the chalk and talk method. The main objective of this study is to find the impact of different sizes of digital boards used for online teaching on muscle activity and muscle fatigue, and then results are compared with conventional writing. Initially, a questionnaire survey is conducted among 100 college professors about the issue they faced while using online teaching methods. Experimental analysis are then conducted using electromyography sensor (sEMG) among ten college professors and their muscle activity on the dominant hand and neck while writing on two commercially available digital boards namely Type 1 (small writing area) and Type 2 (large writing area). Four muscles namely Flexor carpi radialis, Extensor carpi radialis, Biceps brachii, and Sternocleidomastoid (SCM) are chosen for the study. The results are then compared with muscle activity while writing on conventional A4 sheets. Normalized root mean square (RMS) is used to assess the muscle activity and the trend line of MPF value is utilized to assess the muscle fatigue. The results show that SCM muscle has more muscle activation compared to other selected muscles followed by flexor carpi radialis. Subjective analysis is carried out using the Borg scale, which has reported that Type 2 digital board having larger working area was preferred by the participants as it reduces muscle fatigue.