An Overview of Self-Healable Polymers and Recent Advances in the Field

Publisher Copyright: © 2022 The Authors. Macromolecular Rapid Communications published by Wiley-VCH GmbH.The search for materials with better performance, longer service life, lower environmental impact, and lower overall cost is at the forefront of polymer science and material engineering. This has led to the development of self-healing polymers with a range of healing mechanisms including capsular-based, vascular, and intrinsic self-healing polymers. The development of self-healable systems has been inspired by the healing of biological systems such as skin wound healing and broken bone reconstruction. The goal of using self-healing polymers in various applications is to extend the service life of polymers without the need for replacement or human intervention especially in restricted access areas such as underwater/underground piping where inspection, intervention, and maintenance are very difficult. Through an industrial and scholarly lens, this paper provides: a) an overview of self-healing polymers; b) classification of different self-healing polymers and polymer-based composites; c) mechanical, thermal, and electrical analysis characterization; d) applications in coating, composites, and electronics; e) modeling and simulation; and f) recent development in the past 20 years. This review highlights the importance of healable polymers for an economically and environmentally sustainable future, the most recent advances in the field, and current limitations in fabrication, manufacturing, and performance.Peer reviewe

Intrinsic Survival Capacity of Cord Blood T cells is heterogeneous and Can Be Promoted by Repeated Low-Doses of Recombinant Interleukin-7,

Abstract Abstract 3227 Background: Umbilical cord blood (CB) transplantation is known to be associated with delayed and defective immune reconstitution, in part because recent thymic emigrants (RTEs), the most common subset among CB T cells, have limited intrinsic survival. Interleukin-7 (Il-7) has been reported to increase the initial recovery of the graft-derived T-cells compartment. The aim of this study was to investigate CB-derived T-cell survival and to define a minimal effective dose of recombinant human IL-7 (rIL-7), considering that in addition to its anti-apoptotic effect, IL-7 may enhance immune reactions that occur in the host, including uncontrolled acute GVHD. Methods: Fifteen CB were obtained immediately after normal-term delivery, using the same procedure as for CB banking. T cells were isolated within 12 hours by negative magnetic bead sorting and cultured for 2 weeks either directly or after being frozen in order to recapitulate clinical procedures. Unstimulated T cell cultures were conducted in parallel in medium (RPMI supplemented with 10% normal AB serum) alone or supplemented with a range of rIL-7concentrations added either only once at day 0 (100 to 1000 pg/mL) or every day (10 to 100 pg/mL). Cell viability was assessed by flow cytometric scatter analysis and staining with 3,3'-dihexyloxacarbocyanine iodide [DiOC6(3)] and propidium iodide. Results: In basic culture conditions, the majority of T cells had died over 2 weeks, but there was a marked heterogeneity in cell survival, as proportions of viable T cells varied from 2% to 50% (median 15%) at day 6 of culture. Interestingly, the same intrinsic characteristics of survival were observed in T cells that underwent beforehand a freezing-thawing procedure. In cultures supplemented with rIL-7, we confirmed the efficacy of rIL-7 in maintaining CB T cell survival. A minimal dose of 20 to 50 pg/mL of IL-7 added daily was sufficient to induce the prolonged survival of CB T cells, with more than 95% of viable cells at day 6. Noteworthy, these concentrations allowed prolonged survival of CD T cells without inducing any cell proliferation, as shown by the absence of CFSE dilution. Similar results were observed comparing CB cells that had been frozen or not. Conclusion: Repeated low-doses of rIL-7 are required to preserve the survival capacity of CB T cells without inducing their proliferation. These results could represent a framework for clinical studies aiming at improving T cell reconstitution following allogeneic CB transplantation. Repeated administration of low-doses of rIL-7 might be especially useful in patients with low serum levels of IL-7 after conditioning. Disclosures: No relevant conflicts of interest to declare. </jats:sec

Results of a phase II trial of azacitidine (AZA) with or without epoetin beta (EPO) in lower-risk MDS.

6523 Background: Although anemia of IPSS low and int-1 (LR) MDS initially responds to erythroid stimulating agents (ESA) in 40-50% of patients (pts), response is generally transient. Anemia recurrence with RBC cell transfusion dependency (RBC-TD) is an indicator of poor prognosis, even in absence of progression to higher risk MDS. AZA leads to RBC transfusion independence (RBC-TI) in 30–40% of LR-MDS (Lyons, JCO, 2009), but it has not been prospectively tested in LR-MDS patients resistant to ESA. It also remains unknown if the addition of ESA to AZA would be useful in such pts. Methods: In this randomized phase-II trial (GFMAzaEpo-2008-1 trial, NCT01015352), the Groupe Francophone des Myélodysplasies (GFM) compared AZA 75mg/m2/d for 5 days every 28 days for 6 cycles (AZA arm) to the same treatment plus EPO 60000U/week (AZA+EPO arm). Inclusion criteria were LR-MDS resistant to at least 12 weeks of ESA, with RBC-TD ≥ 4 RBC units in the previous 8 weeks. Responders in both arms were eligible for maintenance up to 12 monthly cycles, unless progression or loss of erythroid response occurred. The primary endpoint was RBC-TI (HI-E major using IWG 2000 criteria) after 6 courses. Results: Between 2009 and 2010, the 98 planned pts were included: M/F 65/28; median age 71y (41-84); 5 pts were excluded (one consent withdrawal, 2 early unrelated events and 2 with exclusion criteria). In the remaining 93 pts, IPSS risk was low in 69 and int-1 in 23 pts, with no imbalance between arms. Five pts received &lt; 4 cycles and 16 received only 4 or 5 cycles, mainly due to toxicity or progression. RBC-TI after 6 courses was observed in 16.7% (8/48) in the AZA arm and 18 % (8/45) in the AZA+EPO arm (P=1), and in 19.5% (8/41) and 26 % (8/31) respectively, in the 72 pts who received ≥ 6 cycles (P=.57). Overall best response rate (at least HI-E minor using IWG 2000 criteria) was 35 and 33% in the AZA and AZA+EPO arms, respectively (P=0.99). Of note, only 9 pts in the AZA+EPO arm required at least one hospitalization for a SAE, compared to 22 pts in the AZA arm (P=0.015). Conclusions: Erythroid response to AZA, in LR MDS with demonstrated ESA resistance, appears lower than expected, with no improved outcome when combined with an ESA. The latter may however improve tolerance of AZA in LR MDS. </jats:p