Facile calcium ion-regulated grafting of dense and highly stretched hyaluronan for selective mediation of cancer cells rolling under high-speed flow

The development of materials that selectively mediate the rolling of cancer cells is important for the high-throughput enrichment of high-speed cancer cells. Here we constructed a dense and stretched low molecular weight hyaluronic acid (HA(9.6k))-modified surface to selectively promote the rolling of CD44-high cancer cells. The HA surface (calcium ion-regulated HA(9.6k) surface, Ca-rHA) was fabricated via a calcium ion-regulated method, where calcium ion incorporation induced the shrink of HA(9.6k) chains to achieve the highest reported grafting density of about 2.73 +/- 0.20 x 10(4) HA chains mu m(-2). Upon the removal of calcium ions, the dense HA(9.6k) chains switched to a highly stretched conformation. The high density and flexibility of Ca-rHA bearing abundant binding sites enhanced the rolling of CD44-high cancer cells and reduced the velocity of cells from 1389 mu m s(-1) to 99 mu m s(-1) (7%), comparable to that of the physiological rolling event and outperforming traditional grafting-to HA and E-selectin, without causing phenotypic changes. When processing complex samples under high-speed flow, Ca-rHA selectively mediated the rolling of cancer cells and enriched their ratio to peripheral blood mononuclear cells from 1:1 to 15:1. As the only reported artificial biomaterial capable of selectively mediating the rolling of cancer cells under a physiological high-speed flow, Ca-rHA holds promise in enriching intact cells for downstream analysis in the clinics by encouraging the surface-cell contacts. Statement of significance The development of materials that selectively mediate the rolling of cancer cells is important for the high-throughput enrichment of cancer cells rolling under high-speed flow, yet is less reported. To selectively promote the rolling of cancer stem cell marker CD44-high cancer cells, a surface with dense and stretched low molecular weight hyaluronic acid (HA(9.6k)) was constructed. With Ca2+ regulation, HA(9.6k) chains shrank to achieve the highest reported grafting density of 2.73 +/- 0.20 x 10(4) chains mu m(-2) and further switched to a highly stretched conformation after the removal of Ca2+ ions. As the only reported artificial biomaterial capable of selectively mediating the rolling of cancer cells under a physiological high-speed flow, this Ca2+-regulated HA(9.6k) surface holds promise in enriching intact cells for downstream analysis in the clinics. (C) 2022 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

The selective mediation of cancer cell rolling is important for the high-throughput enrichment of high-speed cancer cells. A dense and stretched low molecular weight hyaluronic acid (HA) surface was constructed to promote the rolling of CD44-high cancer cells. This artificial biomaterial holds promise in enriching intact cells for downstream analysis in the clinics.