Quantum dots-based hydrogel microspheres for visual determination of lactate and simultaneous detection coupled with microfluidic device

As the high concentration of lactate being an important indicator in clinical diagnosis, developing a rapid and effective method for the detection of lactate is of great significance. Herein, quantum dots-based hydrogel microspheres were developed for the rapid detection of lactate via a smartphone. The hydrogel microspheres (Alg@QDs-LOx MSs) were prepared by embedding CdTe quantum dots (QDs) and lactate oxidase (LOx) into alginate hydrogels (Alg). The Alg@QDs-LOx MSs with dense multi-layer network structure exhibits improved storage stability for lactate oxidase and anti-interference ability. The fluorescent microspheres can be employed to differentiate the high lactate levels (>= 2.5 mM) in the human serum within 15 min. In addition, without the requirement of special large instruments, the results can be easily observed with naked eyes or monitored by smartphones, which is more convenient and low-cost. The detection limit of lactate is 1.25 mu M. Furthermore, combing this method with a portable microfluidic device, the simultaneous detection of lactate and uric acid can be realized, proved the universality of this proposed method that can be expanded for simultaneous detection of multiple biomolecules.

Automated summary

A rapid and effective method for lactate detection using quantum dots-based hydrogel microspheres has been developed. The microspheres showed improved storage stability and anti-interference ability, allowing for differentiation of high lactate levels in human serum within 15 minutes. This convenient and low-cost method can be easily observed with naked eyes or monitored by smartphones, demonstrating universality for simultaneous detection of multiple biomolecules when combined with a portable microfluidic device.