DNA-scaffolded multivalent vaccine against SARS-CoV-2.

Short peptides are poor immunogens. One way to increase their immune responses is by arraying immunogens in multivalency. Simple and efficient scaffolds for spatial controlling the inter-antigen distance and enhancing immune activation are required. Here, we report a molecular vaccine design principle that maximally drives potent SARS-CoV-2 RBD subunit vaccine on DNA duplex to induce robust and efficacious immune responses in vivo. We expect that the DNA-peptide epitope platform represents a facile and generalizable strategy to enhance the immune response. STATEMENT OF SIGNIFICANCE: DNA scaffolds offer a biocompatible and convenient platform for arraying immunogens in multivalency antigenic peptides, and spatially control the inter-antigen distance. This can effectively enhance immune response. Peptide (instead of entire protein) vaccines are highly attractive. However, short peptides are poor immunogens. Our DNA scaffolded multivalent peptide immunogen system induced robust and efficacious immune response in vivo as demonstrated by the antigenic peptide against SARS-CoV-2. The present strategy could be readily generalized and adapted to prepare multivalent vaccines against other viruses or disease. Particularly, the different antigens could be integrated into one single vaccine and lead to super-vaccines that can protect the host from multiple different viruses or multiple variants of the same virus.

Low Cost Three-Dimensional Programmed Mini-Pump Used in PCR.

Programmed mini-pumps play a significant role in various fields, such as chemistry, biology, and medicine, to transport a measured volume of liquid, especially in the current detection of COVID-19 with PCR. In view of the cost of the current automatic pipetting pump being higher, which is difficult to use in a regular lab, this paper designed and assembled a three-dimensional programmed mini-pump with the common parts and components, such as PLC controller, motor, microinjector, etc. With the weighting calibration before and after pipetting operation, the error of the pipette in 10 µL (0.2%), 2 µL (1.8%), and 1 µL (5.6%) can be obtained. Besides, the contrast test between three-dimensional programmed mini-pump and manual pipette was conducted with the ORF1ab and pGEM-3Zf (+) genes in qPCR. The results proved that the custom-made three-dimensional programmed mini-pump has a stronger reproducibility compared with manual pipette (ORF1ab: 24.06 ± 0.33 vs. 23.50 ± 0.58, p = 0.1014; pGEM-3Zf (+): 11.83.06 ± 0.24 vs. 11.50 ± 0.34, p = 0.8779). These results can lay the foundation for the functional, fast, and low-cost programmed mini-pump in PCR or other applications for trace measurements.