Saleem, W. | bioRxiv Science

bioRxiv2025

NIR Phosphorescent Oxygen Sensors in Natural Hydrogel Matrices

Understanding the effects of sterilization and other treatments over different hydrogels used as matrices for oxygen-sensitive microparticles is essential in designing biocompatible phosphorescent metabolite sensors. In this study, we dispersed oxygen-sensitive microparticles in hydrogel matrices from various natural sources, such as gelatin, alginate, collagen, and Albumin. Subsequently, we comprehensively analyzed their mechanical and rheological properties and oxygen sensitivity before and after treatments, including autoclave and E-beam sterilization and exposure to serum and cell culture conditions. Our findings, encompassing oxygen sensitivity, compression testing, and rheological profiling, consistently indicate that the E-beam sterilization method yields the most reliable results when applied to alginate and Albumin (BSA) matrices containing oxygen-sensing microparticles. Furthermore, BSA gels exhibited robust stability and performance characteristics, demonstrating minimal structural alterations following post-treatment conditions.

bioengineering↗

bioRxiv2025

IN4MER Bioink: A Phosphorescent Biosensing Bio-ink for Multiple Analytes (Glucose, Lactate, Oxygen) Measurements and Temperature Sensing Applications

3D bioprinting has revolutionized tissue engineering by enabling researchers to create much more complex structures than was practical with earlier techniques. Bioprinting uses computer-controlled layer-by-layer deposition of a mixture of hydrogels and living cells and the resulting structures can mimic the complex geometries of many living tissues by incorporating multiple bioinks with varied material properties and cell populations, allowing researchers to design structures that vary not only in shape, but also in mechanical, chemical, and biological properties throughout the bioprinted construct. However, techniques for evaluating these living constructs and monitoring them over time have not yet caught up to these innovations. Here we describe a novel approach to reporting nutrient values in real-time throughout the scaffold itself, accomplished by dispersing oxygen, glucose, and lactate sensitive microspheres within bioinks. These can be noninvasively interrogated using low-cost phosphorescence lifetime readers to determine and track nutrient concentrations across our bioprinted constructs in real time. The wealth of information this technique produces suggests this may provide a powerful new tool for evaluating and designing future bioprinted constructs.

bioengineering↗