The natural blue colorant C-phycocyanin (C-PC) has many potential applications but its poor heat stability limits its commercial use. This study compares the production and thermal stability of C-PC from two cyanobacteria: the thermophilic Thermosynechococcus sp. TUBT-T01 and the mesophilic Synechococcus cedrorum TISTR8589. Thermosynechococcus sp. produced nearly 1.9-fold more C-PC than S. cedrorum. Batch adsorption using a chromatographic cationic ion exchange resin (Streamline Direct HST1) was used to effectively purify the C-PC. The equilibrium adsorption capacity (Qeq) of the resin for C-PC was the highest at pH 5. At this pH, the Qeq for the thermophilic C-PC was 5.5 ± 0.1 mg mL⁻¹ , whereas for the mesophilic C-PC it was 1.5 ± 0.2 mg mL⁻¹ . Purification increased the concentration of the thermophilic C-PC by 5.9-fold, and that of mesophilic C-PC by 4.2-fold. The purity ratios of the final products from the two cyanobacteria were similar at ∼2.2. At 60 °C and pH 7, the C-PC of Thermosynechococcus sp. had ∼12-times longer half-life than the mesophilic C-PC; however, the productivity of the thermophilic C-PC was comparatively low because of a low biomass productivity of Thermosynechococcus sp.
Nano-optical biosensors have emerged as transformative tools in healthcare and clinical research, offering rapid, portable, and specific diagnostic solutions. This review critically analyzes the recent advancements, translational challenges, and sustainable approaches in nano-optical biosensor implementation for biomedical applications. We explore the integration of innovative nanomaterials, microelectronics, and molecular biology techniques that have significantly enhanced biosensor sensitivity and specificity, enabling detection of biomarkers ranging from cancer indicators to cardiovascular markers. The potential of nanoplasmonic and silicon photonic biosensors in overcoming current limitations is discussed, alongside the promising integration of artificial intelligence and Internet of Things technologies for improved data analytics and clinical validation. We address key challenges, including size constraints, energy efficiency, and integration with existing technologies, and propose sustainable strategies for eco-friendly materials, energy-efficient designs, and circular economy approaches. The review also examines emerging trends such as multiplexed sensing platforms, wearable biosensors, and their applications in personalized medicine. By critically assessing these developments, we provide insights into the prospects of nano-optical biosensors and their potential to revolutionize point-of-care diagnostics and personalized healthcare, while emphasizing the need for interdisciplinary collaboration to overcome remaining obstacles in translating these technologies from laboratory research to real-world clinical applications.