Low-Temperature Processable Block Copolymers That Preserve the Function of Blended Proteins

Abstract

Low-temperature processable polymers have attracted increasing interest as ecological materials because of their reduced energy consumption during processing and suitability for making composites with heat-sensitive biomolecules at ambient temperature. In the current study, low-temperature processable biodegradable block copolymers were synthesized by ring-opening polymerization of l-lactide (LLA) using polyphosphoester as a macroinitiator. The polymer films could be processed under a hydraulic pressure of 35 MPa. The block copolymer films swelled in water because the polyphosphoester block was partially hydrated. Interestingly, the swelling ratio of the films changed with temperature. The pressure-induced order-to-disorder transition of the block copolymers was characterized by small-angle X-ray scattering; a crystallinity reduction in the block copolymers was observed after application of pressure. The crystallinity of the block copolymers was recovered after removing the applied pressure. The Young's modulus of the block copolymer films increased as the LLA unit content increased. Moreover, the modulus did not change after multiple processing cycles and the recyclability of the block copolymers was also confirmed. Finally, polymer films with embedded proteinase K as a model protein were prepared. The activity of catalase loaded into the polymer films was evaluated after processing at different temperatures. The activity of catalase was preserved when the polymer films were processed at room temperature but was significantly reduced after high-temperature processing. The suitability of low-temperature processable biodegradable polymers for making biofunctional composites without reducing protein activity was clarified. These materials will be useful for biomedical and therapeutic applications.

Binary Complex Based on Zein and Propylene Glycol Alginate for Delivery of Quercetagetin

“…The result suggested that the structure of zein was distinctly different from that of Zein-PGA binary complex and Q-loaded Zein-PGA composite. Besides, the curve slopes of binary composites were obviously higher than that of zein, indicating that the particle size became larger after the formation of binary composite colloidal particles. , …”

Hot melt extrusion: An emerging manufacturing method for slow and sustained protein delivery

“…(iii) Fully enzymatic activity of proteinase K is preserved after the high‐pressure process. Adapted with permission from Iwasaki et al (2016) and Taniguchi and Lovell (2012)…”

“…Recently, a novel type of biodegradable baroplastic comprising polyphosphoester and poly( l ‐lactide) (PLLA), PIPP x ‐ b ‐PLLA y block copolymers have been investigated, and proteinase K was incorporated in the system. Full enzymatic activity of proteinase K was obtained after processing under ambient temperature with a pressure of 5076 psi (Iwasaki et al, 2016) (Figure 5b). Another work done by Z. Lv et al (2019) synthesized a poly( n ‐butyl acrylate)@polystyrene (PBA@PS) core–shell polymer, and reinforced the baroplastic by mixing with poly(acrylic acid) and poly(ethylene oxide) through hydrogen‐bonded interaction.…”

Poly(lactic‐co‐glycolic acid) devices: Production and applications for sustained protein delivery

“…This allows for proteins to be processed at the elevated temperatures required for melt encapsulation, however, the encapsulated proteins can still exhibit some denaturation and aggregation depending on the biochemical properties of the protein and additives used. Studies with synthesized block copolymers of poly(ε‐caprolactone)‐ b ‐poly(ethylene glycol)‐ b ‐poly(ε‐caprolactone) and poly(2‐isopropoxy‐2‐oxo‐1,3,2‐dioxaphospholane)‐ b‐ poly( l ‐lactic acid) have yielded biodegradable polymers with melt temperatures in the range of 35–55 °C and were used to encapsulate proteins via melt processing (Iwasaki, Takemoto, Tanaka, & Taniguchi, ; Stanković et al, ; Stanković et al, ). The proteins exhibited enhanced stability when thermally processed at lower temperatures, however, these polymers are not readily available to most researchers.…”