Building Ultrastrong, Tough and Biodegradable Thermoplastic Elastomers from Multiblock Copolyesters via a "Reserve-Release" Crystallization Strategy.

Simultaneously attaining high strength and toughness has been a significant challenge in designing thermoplastic elastomers, especially biodegradable ones. In this context, we present a class of biodegradable elastomers based on multiblock copolyesters that afford extraordinary strength, toughness, and low-strain resilience despite expedient chemical synthesis and sample processing. With the incorporation of the semi-crystalline soft block and the judicious selection of block periodicity, the thermoplastic materials feature low quiescent crystallinity ("reserve") albeit with vast potential for strain-induced crystallization ("release"), resulting in their significantly enhanced ultimate strength and energy-dissipating capabilities. Moreover, a breadth of mechanical responses of the materials - from reinforced elastomers to shape-memory materials to toughened thermoplastics - can be achieved by orthogonal variation of segment lengths and ratios. This work and the "reserve-release" crystallization strategy herein highlight the double crystalline multiblock chain architecture as a potential avenue towards reconciling the strength-toughness trade-off in thermoplastic elastomers and can possibly be extended to other biodegradable building blocks to deliver functional materials with diverse mechanical performances.

One-month DAPT after biodegradable-polymer everolimus-eluting stent implantation in women at high-bleeding risk: Insights from the POEM trial.

AIMS: We conducted a prespecified subanalysis of the POEM trial to assess the association between sex and clinical outcomes following a short 1-month dual-antiplatelet-therapy (DAPT) period after percutaneous coronary intervention (PCI) with bioresorbable polymer everolimus-eluting stent (BP-EES) among patients at high bleeding risk (HBR). BACKGROUND: Shortening the DAPT period after PCI is an effective bleeding avoidance strategy with contemporary drug-eluting stents. Whether sex affects the risk of adverse events following PCI is still debated. METHODS: Patients at HBR undergoing PCI with BP-EES were enrolled and treated with 1-month DAPT. If anticoagulation was needed, study participants received an oral anticoagulant (OAC) in addition to a P2Y12 inhibitor for 1 month, followed by OAC only thereafter. The primary endpoint was a composite of cardiac death, myocardial infarction, or definite/probable stent thrombosis at 12 months. We report sex-based outcomes of patients included in the POEM study. RESULTS: We enrolled 129 (29.1%) women and 314 (70.9%) men. Women were older, with lower hemoglobin levels, and worse renal function. Accordingly, they had a trend for a greater number of HBR criteria fulfilled and a higher PARIS bleeding score. However, they were not at a significantly higher risk for the primary endpoint (men vs. women: 5.17% vs. 3.94%; HR 1.30; 95% CI: 0.48-3.54, p = 0.61), or any of the hemorrhagic and ischemic secondary endpoints. CONCLUSIONS: This prespecified subanalysis of the POEM trial suggests that 1-month DAPT following PCI with BP-EES may be a safe and effective therapeutic strategy for women at HBR.

Engineering Triphasic Nanocomposite Coatings on Pretreated Mg Substrates for Biomedical Applications.

Biodegradable polymer-based nanocomposite coatings provide multiple advantages to modulate the corrosion resistance and cytocompatibility of magnesium (Mg) alloys for biomedical applications. Biodegradable poly(glycerol sebacate) (PGS) is a promising candidate used for medical implant applications. In this study, we synthesized a new PGS nanocomposite system consisting of hydroxyapatite (HA) and magnesium oxide (MgO) nanoparticles and developed a spray coating process to produce the PGS nanocomposite layer on pretreated Mg substrates, which improved the coating adhesion at the interface and their cytocompatibility with bone marrow derived mesenchymal stem cells (BMSCs). Prior to the spray coating process of polymer-based nanocomposites, the Mg substrates were pretreated in alkaline solutions to enhance the interfacial adhesion strength of the polymer-based nanocomposite coatings. The addition of HA and MgO nanoparticles (nHA and nMgO) to the PGS matrix, as well as the alkaline pretreatment of the Mg substrates, significantly enhanced the interfacial adhesion strength when compared with the PGS coating on the nontreated Mg control. The average BMSC adhesion densities were higher on the PGS/nHA/nMgO coated Mg than the noncoated Mg controls under direct contact conditions. Moreover, the addition of nHA and nMgO to the PGS matrix and coating the nanocomposite onto Mg substrates increased the average BMSC adhesion density when compared with the PGS/nHA/nMgO coated titanium (Ti) and PGS coated Mg controls under direct contact. Therefore, the spray coating process of PGS/nHA/nMgO nanocomposites on Mg substrates or other biodegradable metal substrates could provide a promising surface treatment strategy for biodegradable implant applications.

Five-year outcomes of patients with diabetes mellitus treated with a sirolimus-eluting or a biolimus-eluting stents with biodegradable polymer. From the SORT OUT VII trial.

BACKGROUND: Diabetes mellitus is associated with higher risk of target lesion failure (TLF) after percutaneous coronary intervention. We studied the 5-year outcome in patients with diabetes mellitus treated with biodegradable polymer stents. METHODS: The SORT OUT VII was a randomised trial comparing the ultrathin sirolimus-eluting Orsiro stent (O-SES) and the biolimus-eluting Nobori stent (N-BES) in an all-comer setting. Patients (n = 2525) were randomised to receive O-SES (n = 1261, diabetes: n = 236) or N-BES (n = 1264, diabetes: n = 235). Endpoints were TLF (a composite of cardiac death, target-lesion myocardial infarction (MI), target lesion revascularization (TLR)), definite stent thrombosis and a patient related outcome (all-cause mortality, MI and revascularization) within 5 years. RESULTS: Patients with diabetes mellitus had higher TLF (20.6% vs 11.0%, (Rate ratio (RR) 1.85 95% confidence interval (CI): (1.42-2.40) and patient related outcome (42.0% vs 31.0%, RR 1.43 95% CI: (1.19-1.71)) compared to patients without diabetes. Among patients with diabetes mellitus, TLF after 5 years did not differ between O-SES and N-BES (21.2% vs 20.0%), RR 1.05 95% CI: (0.70-1.58), p = 0.81). Cardiac death, MI, TLR, and definite stent thrombosis did not differ between the groups. CONCLUSION: In patients with diabetes mellitus, 5-year outcomes were similar among patients treated with biodegradable polymer O-SES or N-BES. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01879358.

Interrelation of macroscopic mechanical properties and molecular scale thermal relaxation of biodegradable and non-biodegradable polymers.

Comparative analysis of macroscopic mechanical properties of a biodegradable polymer polypropylene carbonate (PPC) is carried out concerning two most commonly used, non-biodegradable synthetic polymers - high-density polyethylene (HDPE) and linear-low density polyethylene (LLDPE). Responses of the films of these polymers when subjected to mechanical and thermal stresses are analyzed. Response to tensile stress reveals the highest elongation at break (EB) in PPC films (396 $\pm$ 104 mm), compared to HDPE (26 $\pm$ 0.5 mm) and LLDPE (301 $\pm$ 143 mm), although the elastic modulus (YM) of PPC is around 50 $\pm$ 6 MPa, 3-fold lesser than LLDPE (YM = 153 $\pm$ 7 MPa) and 6-fold lesser than HDPE (YM = 305 $\pm$ 32 MPa). The plastic deformation response of PPC is intermediate to that of HDPE and LLDPE; initial strain softening is followed by strain hardening in LLDPE, a plateau region in PPC, and prolonged strain softening in HDPE. Crystalline domains in HDPE produce restriction on molecular motion. Crystallinity abruptly decreases by 70 \% in HDPE following a thermal quench, showing the possibility of free chain molecular mobility during plastic deformation. High correlation among Raman modes for all polymers reveals cooperative relaxation processes after thermal quench; C-C stretching modes and C-H bending, CH$_2$ wagging modes have Pearson's correlation coefficient 0.9. The integrated peak intensity and width of the C-C stretching Raman mode is 3-fold higher in PPC than HDPE after a thermal quench, showing enhanced molecular mobility and contributing modes in PPC. The peak width of this mode shows a strong negative correlation of -0.7 with the YM and a strong positive correlation of 0.6 with EB, showing that higher amorphicity leads to enhanced molecular mobility and EB at the cost of YM. This study reveals importance of molecular-scale response in governing the macroscopic properties of polymers.

Advanced roll porous scaffold 3D bioprinting technology.

Improvements in the roll porous scaffold (RPS) 3D bioproduction technology will increase print density of 10-15 µm cells by ~ 20% up to ~ 1.5 × 108 cells/mL and purity of organoid formation by > 17%. The use of 360 and 1200 dpi inkjet printheads immediately enables biomanufacturing with 10-30 µm cells in a single organoid with performance > 1.8 L/h for 15 µm layer thickness. The spongy bioresorbable ribbon for RPS technology is designed to solve the problems of precise placement, leakage and increasing in the number of instantly useable cell types and superior to all currently dominant 3D bioprinting methods in speed, volume, and print density without the use of expensive equipment and components. The potential of RPS for parallel testing of new substances studied was not on animals, but using generated 3D biomodels "organ on a chip". Solid organoids are more suitable for personalized medicine with simultaneous checking of several treatment methods and drugs, targeted therapy for a specific patient in vitro using the 3D composition of his personal cells, and selection of the most effective ones with the least toxicity. Overcoming the shortage of organs for implantation and personal hormone replacement therapy for everyone was achieved using printed endocrine glands based on their DNA.

Long-term effect of biodegradable vs durable polymer everolimus-eluting stents on neoatherosclerosis in ST-segment elevation myocardial infarction: the CONNECT trial.

BACKGROUND AND AIMS: Neoatherosclerosis is a leading cause of late (>1 year) stent failure following drug-eluting stent implantation. The role of biodegradable (BP) versus durable polymer (DP) drug-eluting stents on long-term occurrence of neoatherosclerosis remains unclear. Superiority of biodegradable against durable polymer current generation thin-strut everolimus-eluting stent (EES) was tested by assessing the frequency of neoatherosclerosis 3 years after primary percutaneous coronary intervention (pPCI) among patients with ST-segment elevation myocardial infarction (STEMI). METHODS: The randomized controlled, multicentre (Japan and Switzerland) CONNECT trial (NCT03440801) randomly (1:1) assigned 239 STEMI patients to pPCI with BP-EES or DP-EES. The primary endpoint was the frequency of neoatherosclerosis assessed by optical coherence tomography (OCT) at 3 years. Neoatherosclerosis was defined as fibroatheroma or fibrocalcific plaque or macrophage accumulation within the neointima. RESULTS: Among 239 STEMI patients randomized, 236 received pPCI with stent implantation (119 BP-EES; 117 DP-EES). A total of 178 patients (75%; 88 in the BP-EES group and 90 in the DP-EES group) underwent OCT assessment at 3 years. Neoatherosclerosis did not differ between the BP-EES (11.4%) and DP-EES (13.3%; odds ratio 0.83, 95% confidence interval 0.33-2.04, p=0.69). There were no differences in the frequency of fibroatheroma (BP-EES 9.1% vs DP-EES 11.1%, p=0.66) or macrophage accumulation (BP-EES 4.5% vs DP-EES 3.3%, p=0.68), and no fibrocalcific neoatherosclerosis was observed. Rates of target lesion failure did not differ between groups (BP-EES 5.9% vs DP-EES 6.0%, p=0.97). CONCLUSIONS: Use of BP-EES for primary PCI in patients presenting with STEMI was not superior to DP-EES regarding frequency of neoatherosclerosis at 3 years.

Polish Society of Biomechanics Morecki&Fidelus Award Winner: Comparison of two polymers PDO and PLLA/PCL in application of urological stent for the treatment of male urethral stenosis.

Purpose: The primary objective of the conducted research was to develop an urological stent design for the treatment of male ure-thral stenosis. Given the variable loading conditions inside the urethra, the proposed stent should maintain normal tissue kinetics and obstruct the narrowed lumen. The suitable selection for the stent material significantly influences the regeneration and proper remodeling of the urethral tissues. Methods: In this work, the mechanical characteristics of some polymer materials were studied, including: polydi-oxanone (PDO) and poly(L-lactide) (PLLA)/polycaprolactone (PCL) composite. The obtained mechanical properties for static tensile testing of the materials, allowed the determination of such parameters as Young's modulus (E), tensile strength (R m) and yield strength (R e). Subsequently, the design of a urological stent was developed, for which a numerical analysis was carried out to check the behaviour of the stent during varying loads prevailing in the urethra. Result: The research indicated that PDO has better mechanical properties than the proposed PLLA/PCL composite. The numerical analysis results suggested that the developed stent design can be successfully used in the treatment of male urethral stenosis. The obtained stress and strain distributions in the numerical analysis confirm that the PDO material can be used as a material for an urological stent. Conclusions: The biodegradable polymers can be successfully used in urology. Their advantages over solid materials are their physicochemical properties, the ability to manipulate the rate and time of degradation and the easy availability of materials and manufacturing technology.

Properties of biodegradable polymer coatings with hydroxyapatite on a titanium alloy substrate.

Purpose: Titanium alloys are among the most widely used materials in medicine, especially in orthopedics. However, their use requires the application of an appropriate surface modification method to improve their properties. Such methods include anodic oxidation and the application of polymer coatings, which limit the release of alloying element ions. In addition, biodegradable polymer coatings can serve as a carrier for drugs and other substances. The paper presents the results of research on the physical properties of biodegradable polymer coatings containing nanoparticle hydroxyapatite on a titanium alloy substrate. Methods: A PLGA coating was used in the tests. The coatings on the substrate of the anodized Ti6Al7Nb alloy were applied by ultrasonic spray coating. The tests were carried out for coatings with various hydroxyapatite content (5, 10, 15, 20%) and thickness resulting from the number of layers applied (5, 10, 15 layers). The scope of the research included microscopic observations using scanning electron microscopy, topography tests with optical profilometry, structural studies using X-ray diffraction, as well as wettability and adhesion tests. Results: The results shows that with the use of ultrasonic spray coating system is possible to obtain the continuous coatings containing hydroxyapaptite. Conclusions: The properties of the coating can be controlled by changing the percentage of hydroxyapatite and the number of layers of which the coating is composed.

Effects of biodegradable microplastics on the crustacean isopod Idotea balthica basteri Audouin, 1826.

Plastic pollution is a notable environmental issue, being plastic widespread and characterized by long lifetime. Serious environmental problems are caused by the improper management of plastic end-of-life. In fact, plastic litter is currently detected in any environment. Biodegradable Polymers (BPs) are promising materials if correctly applied and managed at their end of life, to minimize environmental problems. However, poor data on the fate and toxicity of BPs on marine organisms still limit their applicability. In this work we tested the effects of five biodegradable polymers (polybutylene succinate, PBS; polybutylene succinate-co-butylene adipate, PBSA; polycaprolactone, PCL; poly (3-hydroxybutyrates, PHB; polylactic acid, PLA) widely used for several purposes. Adult individuals of the isopod Idotea balthica basteri were fed on these polymers for twenty-seven days by adding biodegradable microplastic polymers (BMPs) to formulated feeds at two concentrations, viz. 0.84 and 8.4 g/kg feed. The plastic fragments affected the mortality rates of the isopods, as well as the expression levels of eighteen genes (tested by Real Time qPCR) involved in stress response and detoxification processes. Our findings confirmed that I. balthica basteri is a convenient model organism to study the response to environmental pollution and emerging contaminants in the aquatic environment, and highlighted the need for the correct use of BMPs.

Measuring Erosion of Biodegradable Polymers in Brimonidine Drug Delivery Implants by Quantitative Proton NMR Spectroscopy (q-HNMR).

Erosion of biodegradable polymeric excipients, such as polylactic acid (PLA) and polylactic-co-glycolic acid (PLGA), is generally characterized by microbalance for the remaining mass of PLA and/or PLGA and Gel Permeation Chromatography (GPC) for molecular weight (MW) decrease. For polymer erosion studies of intravitreal sustained release brimonidine implants, however, both microbalance and GPC present several challenges. Mass loss measurement by microbalance does not have specificity for excipient polymers and drug substances. Accuracy of the remaining mass by weighing could also be low due to sample mass loss through retrieval-drying steps, especially at later drug release (DR) time points. When measuring the decrease of polymer MW by GPC, trace amounts of polymeric degradants (oligomers and/or monomers) trapped inside the implants during DR tests may not be measurable due to sensitivity limitations of the GPC detector and column MW range. Previous efforts to measure remained PLGA weight of dexamethasone micro-implants using qNMR with external calibration have been performed, however, these measurements do not account for chemical structure changes (i.e. LA to GA ratio changes from time zero) of PLGA implants during drug release tests. Here, a qNMR method with an internal standard was developed to monitor the following changes in micro-implants during drug release tests: 1. The remaining overall PLA/PLGA mass. 2. The remaining lactic acid (LA), glycolic acid (GA) unit and PLGA's lauryl ester end group percentages. 3. The trace content of PLA/PLGA oligomers as degradants retained in the implants. Unlike microbalance analysis, qNMR has both specificity for drug substance, excipient polymer, and accuracy due to minimal implant loss during sample preparation. Compared to the overall PLA/PLGA remaining mass generally monitored in erosion studies, the percentage of remaining LA, GA, and the ester end group provide more information about the microstructure change (such as hydrophobicity) of PLA/PLGA. Additionally, the qNMR method can complement GPC methods by measuring the change of remaining PLA and PLGA oligomer concentrations in brimonidine implants, with tenfold less sample and no MW cutoff. The qNMR method can be used as a sensitive tool for both polymer excipient characterization and kinetics studies of brimonidine implant erosion.

Biodegradable Zwitterionic Polymers as PEG Alternatives for Drug Delivery.

Poly(ethylene glycol) (PEG) is a highly biocompatible and water-soluble polymer that is widely utilized for biomedical applications. Unfortunately, the immunogenicity and antigenicity of PEG severely restrict the biomedical efficacy of pegylated therapeutics. As emerging PEG alternatives, biodegradable zwitterionic polymers (ZPs) have attracted significant interest in recent years. Biodegradable ZPs generally are not only water-soluble and immunologically inert, but also possess a range of favorable biomedically relevant properties, without causing long-term side effects for in vivo biomedical applications. This review presents a systematic overview of recent studies on biodegradable ZPs. Their structural designs and synthetic strategies by integrating biodegradable base polymers with zwitterions are addressed. Their applications in the delivery of small molecule drugs (as mono-drugs or multi-drugs) and proteins are highlighted.

One-month DAPT after biodegradable-polymer everolimus-eluting stent implantation in patients at high-bleeding risk: an individual patient data pooled analysis of the SENIOR and POEM trials.

Aims: Dual antiplatelet therapy (DAPT) can be shortened up to 1 month in high-bleeding risk (HBR) patients receiving a contemporary biodegradable-polymer sirolimus-eluting stent. We aimed to summarize the evidence on a similar DAPT regimen after biodegradable-polymer everolimus-eluting stent (EES) implantation in patients at HBR. Methods and results: We pooled the individual participant data from the available trials evaluating this strategy, namely, the SENIOR and the POEM trials. Inclusion criteria were ≥1 biodegradable-polymer EES implantation and ≤1-month duration of DAPT. The primary endpoint was the 1-year composite of cardiovascular death, myocardial infarction, or stroke. Major bleeding was defined as Bleeding Academic Research Consortium (BARC) type 3-5 bleeding. Landmark analyses were performed at 1 month, the time point for intended DAPT interruption. We included 766 participants (age 77.5 ± 8.2 years, women 31.9%), 323 from the SENIOR and 443 from the POEM trial. The primary endpoint occurred in 45 participants (6.0%; 95% confidence interval [CI], 4.3-7.7%) through 1 year of follow-up, with 21 (2.8%; 95% CI, 1.6-3.9%) events during the first month and 24 (3.4%; 95% CI, 2.0-4.7%) thereafter. The incidences of cardiovascular death, myocardial infarction, and stroke were 2.2% (95% CI, 0.36-2.50%), 3.1% (95% CI, 1.8-4.3%), and 1.2% (95% CI, 0.4-2.0%), respectively. BARC type 3-5 bleeding ocuurred in 1.1% (95% CI, 0.3-1.8%) at 1 month and 2.9% (95% CI, 1.6-4.1%) at 1 year. Conclusion: HBR patients receiving biodegradable-polymer EES had few ischemic and bleeding events when given 1 month of DAPT. One-month DAPT after biodegradable-polymer EES implantation seems safe in patients at HBR.

Bioinformatic and functional analysis of a PHB polymerase (PhbC) from Azospirillum baldaniorum.

BACKGROUND: Azospirillum baldaniorum Sp245 produces poly-ß-hydroxybutyrate, a biodegradable polymer with characteristics similar to synthetic thermoplastics, including polypropylene. In the synthesis pathway, the poly-ß-hydroxybutyrate synthase enzyme uses thioesters of 3-hydroxy butyryl-CoA as a substrate and catalyzes their polymerization with HS-CoA release. METHODS: A study was conducted using in silico analysis of the two phbC genes of A. baldaniorum Sp245. One was selected for amplification and cloning into the pEXP5- CT/TOPO® vector, which was analysed by restriction pattern, polymerase chain reaction, and sequencing. SDS-PAGE analysis determined the molecular weight of the PhbC1 protein from Azospirillum baldaniorum (AbPhbC1). The presence of the protein was confirmed by Western blotting using anti-polyhistidine monoclonal antibodies. The enzymatic activity in the crude extract of AbPhbC1 was determined by measuring the concentration of sulfhydryl groups using the Ellman method. A UV-Vis assay was performed. To confirm the presence of the poly-ß-hydroxybutyrate product, an NMR assay was performed. RESULTS: In silico analyses, it is revealed that AbPhbC1 and the PhbC2 protein from Azospirillum baldaniorum (AbPhbC2) retain the poly-ß-hydroxybutyrate polymerase and α/ß hydrolase domain. The Cys-His-Asp catalytic triad is highly conserved in all four polyß-hydroxyalkanoate synthases in the central subdomain, structurally similar to the reported crystallized proteins. The dimerization subdomain is different; in AbPhbC1, it is in the closed form; in AbPhbC2, it is in the open form; and in AbPhbC2, it lacks the EC region as class III and IV poly-ß-hydroxyalcanoate synthases. In vitro, the molecular weight of AbPhbC1 was 68 kDa. The polymerization of PHB by AbPhbC1 was detected by the release of HS-CoA from the quantification of SH. The UV-Vis scan showed a characteristic peak at 264 nm. A comparison of the NMR spectra of the bacterial and commercial poly-ß-hydroxybutyrate samples suggested their presence. CONCLUSION: In silico analyses suggested that AbPhbC1 and AbPhbC2 are structurally functional, except that AbPhbC2 might require the PhaR subunit for its activity; this strongly suggests that it could be a class IV poly-ß-hydroxyalcanoate synthase. UV-Vis scanning and NMR spectroscopy revealed the synthesis of poly-ß-hydroxybutyrate by the A. baldaniorum enzyme AbPhbC1, indicating that the enzyme is functional.

Effect of the Addition of PLA on the Thermal and Mechanical Properties of Reprocessed HDPE.

Amid the current environmental crisis caused by plastic accumulation, one of the proposed solutions to manage this problem is using biodegradable polymers. However, the impact of adding biodegradable polymers to the well-established circular economy of recyclable polymers, such as HDPE, has not been fully considered. Therefore, there is a need to reconsider the way we consume, dispose of, and manage biodegradable polymers after use. This study evaluates the effect of varying the contents of a biodegradable polymer, taking poly(lactic acid) (PLA) as a model biodegradable polymer, on the thermal and mechanical properties of HDPE. The study highlights the importance of identifying and disposing of biodegradable polymers to avoid mixtures with HDPE, in order not to affect mechanical performance when considering reprocessing and a new life cycle of this conventional polymer.

Brain Nucleic Acid Delivery and Genome Editing via Focused Ultrasound-Mediated Blood-Brain Barrier Opening and Long-Circulating Nanoparticles.

We introduce a two-pronged strategy comprising focused ultrasound (FUS)-mediated blood-brain barrier (BBB) opening and long-circulating biodegradable nanoparticles (NPs) for systemic delivery of nucleic acids to the brain. Biodegradable poly(ß-amino ester) polymer-based NPs were engineered to stably package various types of nucleic acid payloads and enable prolonged systemic circulation while retaining excellent serum stability. FUS was applied to a predetermined coordinate within the brain to transiently open the BBB, thereby allowing the systemically administered long-circulating NPs to traverse the BBB and accumulate in the FUS-treated brain region, where plasmid DNA or mRNA payloads produced reporter proteins in astrocytes and neurons. In contrast, poorly circulating and/or serum-unstable NPs, including the lipid NP analogous to a platform used in clinic, were unable to provide efficient nucleic acid delivery to the brain regardless of the BBB-opening FUS. The marriage of FUS-mediated BBB opening and the long-circulating NPs engineered to copackage mRNA encoding CRISPR-associated protein 9 and single-guide RNA resulted in genome editing in astrocytes and neurons precisely in the FUS-treated brain region. The combined delivery strategy provides a versatile means to achieve efficient and site-specific therapeutic nucleic acid delivery to and genome editing in the brain via a systemic route.

Electronic skin based on natural biodegradable polymers for human motion monitoring.

The wearability of the flexible electronic skin (e-skin) allows it to attach to the skin for human motion monitoring, which is essential for studying human motion and especially for assessing how well patients are recovering from rehabilitation therapy. However, the use of non-degradable synthetic materials in e-skin may raise skin safety concerns. Natural biodegradable polymers with advantages such as biodegradability, biocompatibility, sustainability, natural abundance, and low cost have the potential to be alternative materials for constructing flexible e-skin and applying them to human motion monitoring. This review summarizes the applications of natural biodegradable polymers in e-skin for human motion monitoring over the past three years, focusing on the discussion of cellulose, chitosan, silk fibroin, gelatin, and sodium alginate. Finally, we summarize the opportunities and challenges of e-skin based on natural biodegradable polymers. It is hoped that this review will provide insights for the future development of flexible e-skin in the field of human motion monitoring.

In Vitro Corrosion of Polyester-Coated Magnesium Alloy under pH-Static Conditions.

The resorption rate of bioresorbable implants requires tuning to match the desired field of application. The use of Mg as implant material is highly advantageous, as it provides sufficient mechanical strength combined with its biodegradability. Consequently, the implant vanishes after it has served its intended purpose, allowing the complete restoration of natural tissue and organ function. However, a biodegradable Mg implant requires a biodegradable coating to slow the rate of Mg corrosion, as a permanent coating would negate the benefits of using Mg as an implant material. Therefore, degradable polymers are the materials of choice, especially polyester-based coatings, such as PLLA, as they have been proven in clinical practice over the long term. Within this work, the degradation retarding effect of a physical barrier in form of four clinically relevant polyester-based coatings, poly-l-lactide (PLLA), poly-l-lactide-co-glycolide (PLGA), poly(l-lactide-co-PEG) triblock copolymer (PLLA-co-PEG), and polydioxanone (PDO), is investigated in vitro under pH-static conditions using CO2 gas to compensate pH changes due to Mg corrosion. Coating thicknesses of 7.5 to 8.3 µm were comparable to commercially available stent systems. Quantitative analysis of magnesium concentration in buffered test medium by a photometric assay allows real-time monitoring. Shielding effect of different polyesters through polymer coating and formation of a protective passivation layer beneath the polymer coating was observed and characterized using SEM and EDX techniques. Our finding was that even imperfect polymer layers provide a considerable protective effect, and the used in vitro setup matches reported in vivo observations regarding elemental composition of corrosion products.

Development of Versatile, thermally stable, flexible, UV-resistant and antibacterial polyvinyl alcohol-Nanodiamonds composite for efficient food packaging.

This research paper reports an enhancement of thermal, optical, mechanical and antibacterial activities of the Polyvinyl alcohol-Nanodiamonds (PVA-NDs) composite required for the food packaging industry. The synthesis of composites was done by the wet processing method. The large surface area of NDs facilitated the robust interaction between the hydroxyl group and macromolecular chains of PVA to enhance the hydrogen bonding of PVA with NDs rather than PVA molecules. Thus, a reduction in PVA diffraction peak intensity was reported. NDs improved the thermal stability by preventing the out-diffusion of volatile decomposition products of PVA. The results also revealed an enhancement in tensile strength (∼60 MPa) and ductility (∼180 %). PVA-NDs composite efficiently blocked the UVC (100 %), most of the part of the UVB (∼85 % above 300 nm), and UVA (∼58 %). Furthermore, enhanced antibacterial activities were reported for PVA-NDs composite against E. coli and S. aureus. NDs accumulated around the bacterial cells prevented essential cellular functions and led to death. Hence, this composite could be a promising candidate for safe, thermally stable, strong, flexible, transparent, UV- resistant antibacterial food packaging material.

Green synthesis of chitosan gum acacia based biodegradable polymeric nanoparticles to enhance curcumin's antioxidant property: an in vivo zebrafish (Danio rerio) study.

Green-synthesis of biodegradable polymeric curcumin-nanoparticles using affordable biodegradable polymers to enhance curcumin's solubility and anti-oxidative potential. The curcumin-nanoparticle was prepared based on the ionic-interaction method without using any chemical surfactants, and the particle-size, zeta-potential, surface-morphology, entrapmentefficiency, and in-vitro drug release study were used to optimise the formulation. The antioxidant activity was investigated using H2DCFDA staining in the zebrafish (Danio rerio) model. The mean-diameter of blank nanoparticles was 178.2 nm (±4.69), and that of curcuminnanoparticles was about 227.7 nm (±10.4), with a PDI value of 0.312 (±0.023) and 0.360 (±0.02). The encapsulation-efficacy was found to be 34% (±1.8), with significantly reduced oxidative-stress and toxicity (∼5 times) in the zebrafish model compared to standard curcumin. The results suggested that the current way of encapsulating curcumin using affordable, biodegradable, natural polymers could be a better approach to enhancing curcumin's water solubility and bioactivity, which could further be translated into potential therapeutics.