ABSTRACT
Rapid diagnostics for the diagnosis of COVID-19 are urgently needed in offices, residences, and other public places due to the new Covid epidemic stages. A portable and easy-to-use immunosensing platform was developed and evaluated for a point-of-care and self-detection of SARS-CoV-2 spike protein without the need for extraction, separation, or amplification steps using clinically isolated samples (n = 40 samples). The sensing platform was fabricated based on functionalized nylon nanofibrous membranes and a commercial glucose meter to enable easy deployment of the sensing technology. The fabrication of the immunoreaction vial using nylon nanofibrous membranes as a support matrix for the tethering of antibodies significantly improved the sensitivity of the detection platform in contrast to the use of conventional nylon casted membranes. The sensitivity of the nanofibrous membrane attached antibody was at least an order of magnitude higher (∼12 times) compared to the sensitivity of detection with regular casted membrane-based immunoreaction vial. The feasibility of the designed sensing platform was investigated using saliva as a non-invasive and self-administered sample for the diagnosis of SARS-CoV-2. With a detection limit of 9 ng mL−1 and no pretreatment processes required, the sensing platform demonstrated its suitability for the direct detection of SARS-CoV-2 spike protein in the spiked saliva samples. In addition, the developed platform depicted high agreement with RT-qPCR data in the analysis of the clinical samples with good stability over the storage time and reusability for three cycles with maintaining more than 95% of its original activity. [Display omitted] • Diagnosis of COVID-19 in human saliva using commercial glucose meter. • High sensitivity with broad dynamic range was achieved using nanofibrous membrane. • Successfully analyzing of clinical samples in agreement with RT-qPCR. • Potential application for self- and on-site diagnosis without sample pretreatment. • The sensing platform depicted reusability for 3 cycles and good storage stability. [ FROM AUTHOR]
ABSTRACT
Rapid diagnostics for the diagnosis of COVID-19 are urgently needed in offices, residences, and other public places due to the new Covid epidemic stages. A portable and easy-to-use immunosensing platform was developed and evaluated for a point-of-care and self-detection of SARS-CoV-2 spike protein without the need for extraction, separation, or amplification steps using clinically isolated samples (n = 40 samples). The sensing platform was fabricated based on functionalized nylon nanofibrous membranes and a commercial glucose meter to enable easy deployment of the sensing technology. The fabrication of the immunoreaction vial using nylon nanofibrous membranes as a support matrix for the tethering of antibodies significantly improved the sensitivity of the detection platform in contrast to the use of conventional naylon casted membranes. The sensitivity of the nanofibrous membrane attached antibody was at least an order of magnitude higher (∼12 times) compared to the sensitivity of detection with regular casted membrane-based immunoreaction vial. The feasibility of the designed sensing platform was investigated using saliva as a non-invasive and self-administered sample for the diagnosis of SARS-CoV-2. With a detection limit of 9 ng mL−1 and no pretreatment processes required, the sensing platform demonstrated its suitability for the direct detection of SARS-CoV-2 spike protein in the spiked saliva samples. In addition, the developed platform depicted high agreement with RT-qPCR data in the analysis of the clinical samples with good stability over the storage time and reusability for three cycles with maintaining more than 95% of its original activity.
ABSTRACT
The aggregation-caused self-quenching of photosensitizers (PS), especially on a solid substrate, has highly limited their photo-induced biocidal efficiency in practical applications. Here, we designed a unique "posture" of rose Bengal (RB) on cotton-based super-adsorptive fibrous equipment, with RB being separately captured in the mesopores of porous organic polymers (POPs). The resultant daylight-induced biocidal cotton fabric with enhanced efficiency was named as DBwEE-Cotton. The enhanced biocidal activity of the DBwEE-Cotton was achieved based on two mechanisms: (1) the separation of RB in mesopores on the fabric avoids the aggregation-caused self-quenching; and (2) other than singlet oxygen generation, RB is forced to undergo type I photoreaction by surrounding the RB with massive amounts of good hydrogen donors (i.e., POP) under daylight irradiation. Given the enhanced production efficiency of reactive oxygen species by the DBwEE-Cotton, 99.9999% of E. coli and L. innocua bacteria were killed within 20 min of daylight exposure. The DBwEE-Cotton also presents excellent wash and light durability with no biocidal function loss. The development of DBwEE-Cotton provides a facile strategy of avoiding aggregation-caused self-quenching and modulating photoreactions of PS on a flexible substrate, which may guide the design of novel personal protective equipment (PPE) integrated with improved biocidal efficiency, wearability, and repeated and long-term applicability for protecting people from lethal infectious diseases.
ABSTRACT
Cotton fabrics with durable and reusable daylight-induced antibacterial/antiviral functions were developed by using a novel fabrication process, which employs strong electrostatic interaction between cationic cotton fibers and anionic photosensitizers. The cationic cotton contains polycationic short chains produced by a self-propagation of 2-diehtylaminoehtyl chloride (DEAE-Cl) on the surface of cotton fibers. Then, the fabric (i.e., polyDEAE@cotton) can be readily functionalized with anionic photosensitizers like rose Bengal and sodium 2-anthraquinone sulfate to produce biocidal reactive oxygen species (ROS) under light exposure and consequently provide the photo-induced biocidal functions. The biocidal properties of the photo-induced fabrics (PIFs) were demonstrated by ROS production measurements, bactericidal performance against bacteria (e.g., E coli and L. innocua), and antiviral results against T7 bacteriophage. The PIFs achieved 99.9999% (6 log) reductions against bacteria and the bacteriophage within 60 min of daylight exposure. Moreover, the PIFs showcase excellent washability and photostability, making them ideal materials for reusable face masks and protective suits with improved biological protections compared with traditional PPE. This work demonstrated that the cationized cotton could serve as a platform for different functionalization applications, and the resulting fiber materials could inspire the development of reusable and sustainable PPE with significant bioprotective properties to fight the COVID-19 pandemic as well as the spread of other contagious diseases.