Dual-Gated Microparticles for Switchable Antibody Release

Abstract

We pioneer the design of dual-gated microparticles, both responsive to changes in temperature and pH, for stimuli-responsive chromatography targeted at the efficient separation of antibodies. Dual-gated microspheres were synthesized by introducing RAFT-based thiol-terminal block copolymers of poly(N-isopropylacrylamide-b-4-vinylpyridine) (P(NIPAM-b-4VP, 4800 ≤ M/Da ≤ 10 000, featuring block length ratios of 29:7, 29:15, and 29:30, respectively) by thiol-epoxy driven ligation to the surface of poly(glycidyl methacrylate) (PGMA) microparticles (10-12 μm), whereby the 4-vinylpyridine units within the lateral chain enable protein binding. The switchable protein release abilities of the resulting microparticle resins are demonstrated by adsorption of immunoglobulins at 40 °C and pH 8 and their release at 5 °C or pH 3, respectively. We demonstrate that P(NIPAM-b-4VP)-grafted PGMA particles show a maximum adsorption capacity for immunoglobulins of 18.9 mg mL settled resin at 40 °C/pH 8, whereas the adsorption capacity decreased to 7.5 mg mL settled resin at 5 °C while retaining the pH value, allowing the unloading of the chromatographic column by a facile temperature switch. Critically, regeneration of the dual-gated microspheres became possible by lowering the pH to 3.

Polyurethane Microparticles for Stimuli Response and Reduced Oxidative Degradation in Highly Porous Shape Memory Polymers

“…TEA was selected for further examination due to particle size and distribution as well as the suspected less hydrophilic network and more rapid release/degradation rates previously demonstrated in noncomposite porous SMPs . While the smallest size distribution was achieved with HPED ( D w / D n = 1.10), TEA at room temperature resulted in the smallest particle diameter, similar to those results reported by Kong and others using similar methods. , Results obtained by changing the temperature indicated that room temperature gave the smallest particle diameter of 2.43 ± 0.91 μm, a size that falls within the desired range for embolic applications and for particles that can be phagocytized by cells. , …”

Dynamic Nitroxide Functional Materials

“…EPR spectroscopic determination of the paramagnetic properties of MS1 unambiguously confirmed the presence of surface‐immobilized nitroxides indicated by a broad EPR signal, as shown in Figure a. The C 1s XP spectrum of MS1 only showed minor changes compared to that of the unmodified PGMA microspheres, attributed to the predominant signals derived from the underlying glycidyl methacrylate structural motifs and similar chemical composition of the ad‐layer poly(catecholamine) matrix (Figure b) . In‐depth analysis of the obtained N 1s XP spectrum, however, clearly revealed successful thin nitroxide polymer ad‐layer modification of MS1 with two deconvoluted main components.…”

Preprogrammed Dynamic Microstructured Polymer Interfaces

“…For example, particles decorated with poly(4-vinylpyridine) were used as a recyclable sorbent for water purification when pollutants were adsorbed by the polymer in its protonated form and subsequently released upon deprotonation [65] . Furthermore, multi-responsive PDMPI exploiting a combination of changes in pH and temperature were used for separation of antibodies, [66] recycling of Cd-ions, [67] extraction of bisphenol A [68] , and uptake and release of trivalent lanthanum ions [69] and therapeutic drugs. [70] It was also demonstrated that alternation of the response of PDMPI to external stimuli due to binding of ligand molecules to PDMPI could find applications for sensor technology.…”