Evaluation of setting kinetics, mechanical strength, ion release, and cytotoxicity of high-strength glass ionomer cement contained elastomeric micelles.

BACKGROUND: Low mechanical properties are the main limitation of glass ionomer cements (GICs). The incorporation of elastomeric micelles is expected to enhance the strength of GICs without detrimentally affecting their physical properties and biocompatibility. This study compared the chemical and mechanical properties, as well as the cytotoxicity, of elastomeric micelles-containing glass ionomer cement (DeltaFil, DT) with commonly used materials, including EQUIA Forte Fil (EF), Fuji IX GP Extra (F9), and Ketac Molar (KT). METHOD: Powder particles of GICs were examined with SEM-EDX. Setting kinetics were assessed using ATR-FTIR. Biaxial flexural strength/modulus and Vickers surface microhardness were measured after immersion in water for 24 h and 4 weeks. The release of F, Al, Sr, and P in water over 8 weeks was analyzed using a fluoride-specific electrode and ICP-OES. The toxicity of the material extract on mouse fibroblasts was also evaluated. RESULTS: High fluoride levels in the powder were detected with EF and F9. DT demonstrated an initial delay followed by a faster acid reaction compared to other cements, suggesting an improved snap set. DT also exhibited superior flexural strength than other materials at both 24 h and 4 weeks but lower surface microhardness (p < 0.05). EF and F9 showed higher release of F, Al, and P than DT and KT. There was no statistically significant difference in fibroblast viability among the tested materials (p > 0.05). CONCLUSIONS: Elastomeric micelles-containing glass ionomer cement (DT) exhibited satisfactory mechanical properties and cytocompatibility compared with other materials. DT could, therefore, potentially be considered an alternative high-strength GIC for load-bearing restorations.

Nanoscale Simulation of Plastic Contaminants Migration in Packaging Materials and Potential Leaching into Model Food Fluids.

Polymers are the most commonly used packaging materials for nutrition and consumer products. The ever-growing concern over pollution and potential environmental contamination generated from single-use packaging materials has raised safety questions. Polymers used in these materials often contain impurities, including unreacted monomers and small oligomers. The characterization of transport properties, including diffusion and leaching of these molecules, is largely hampered by the long timescales involved in shelf life experiments. In this work, we employ atomistic molecular simulation techniques to explore the main mechanisms involved in the bulk and interfacial transport of monomer molecules from three polymers commonly employed as packaging materials: polyamide-6, polycarbonate, and poly(methyl methacrylate). Our simulations showed that both hopping and continuous diffusion play important roles in inbound monomer diffusion and that solvent-polymer compatibility significantly affects monomer leaching. These results provide rationalization for monomer leaching in model food formulations as well as bulky industry-relevant molecules. Through this molecular-scale characterization, we offer insights to aid in the design of polymer/consumer product interfaces with reduced risk of contamination and longer shelf life.

CO2-Based Polycarbonates through Ring-Opening Polymerization of Cyclic Carbonates Promoted by a NHC-Based Zinc Complex.

A backbone-substituted N-heterocyclic carbene (NHC) zinc complex, in combination with alcohol initiators, has been shown to be an effective catalyst for the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) to poly(trimethylene carbonate) (PTMC) devoid of oxetane linkages. The ROP of TMC proceeded in solution to give PTMC, possessing controlled molecular mass (2500 < Mn < 10000) and low dispersity (D ∼ 1.2). Changing the alcohol initiators, PTMCs with different end-groups were obtained, included a telechelic polymer. The results of MALDI-ToF and NMR analysis confirmed the controlled/living nature of the present ROP catalytic system, where side reactions, such as inter- and intramolecular transesterifications, were minimized during the polymerization. Solution studies in different solvents demonstrated the polymerization reaction to proceed via a mechanism first order in monomer and in catalyst. The zinc complex was also able to convert substituted cyclic carbonates, which were purposely synthesized from renewable feedstocks such as CO2 and 1,3-diols. For the asymmetric 2-Me TMC monomer, good regioselectivity was observed (Xreg up to 0.92). The excellent control of the polymerization process was finally brought to light through the preparation of polycarbonate/polyether triblock copolymers by using polyethylene glycol (PEG) as a macroinitiator and of well-defined di- and triblock polycarbonate/polylactide copolymers by sequential ROP of TMC and L-LA.

PEG-functionalized aliphatic polycarbonate brushes with self-polishing dynamic antifouling properties.

Hydrophilic antifouling polymers provide excellent antifouling effects under usual short-term use conditions, but the long-term accumulation of contaminants causes them to lose their antifouling properties. To overcome this drawback, surface-initiated ring-opening graft polymerization (SI-ROP) was performed on the surface of the material by applying the cyclic carbide monomer 4'-(fluorosulfonyl)benzyl-5-methyl-2-oxo-1,3-dioxane-5-carboxylate (FMC), which contains a sulfonylfluoride group on the side chain, followed by a "sulfur(IV)-fluorine exchange" (SuFEx) post click modification reaction to link the hydrophilic polyethylene glycol (PEG) to the polyFMC (PFMC) brush, and a novel antifouling strategy for self-polishing dynamic antifouling surfaces was developed. The experimental results showed that the antifouling surface could effectively prevent the adsorption of proteins such as bovine serum albumin (BSA, ∼96.4%), fibrinogen (Fg, ∼87.8%) and lysozyme (Lyz ∼69.4%) as well as the adhesion of microorganisms such as the bacteria Staphylococcus aureus (S. aureus) (∼87.5%) and HeLa cells (∼67.2%). Moreover, the enzymatically self-polished surface still has excellent antifouling properties. Therefore, this modification method has potential applications in the field of biosensors and novel antifouling materials.

Silver nanopopcorns decorated on flexible membrane for SERS detection of nitrofurazone.

The synthesis of three-dimensional silver nanopopcorns (Ag NPCs) onto a flexible polycarbonate membrane (PCM) for the detection of nitrofurazone (NFZ) on the fish surface by surface-enhanced Raman spectroscopy (SERS) is presented. The proposed flexible Ag-NPCs/PCM SERS substrate exhibits significant Raman signal intensity enhancement with the measured enhancement factor of 2.36 × 106. This is primarily attributed to the hotspots created on Ag NPCs, including numerous nanoscale protrusions and internal crevices distributed across the surface of Ag NPCs. The detection of NFZ by this flexible SERS substrate demonstrates a low limit of detection (LOD) of 3.7 × 10-9 M and uniform and reproducible Raman signal intensities with a relative standard deviation below 8.34%. It also exhibits excellent stability, retaining 70% of its efficacy even after 10 days of storage. Notably, the practical detection of NFZ in tap water, honey water, and fish surfaces achieves LOD values of 1.35 × 10-8 M, 5.76 × 10-7 M, and 3.61 × 10-8 M, respectively,  which highlights its effectiveness across different sample types. The developed Ag-NPCs/PCM SERS substrate presents promising potential for sensitive SERS detection of toxic substances in real-world samples.

Toward a disruptive, minimally invasive small finger joint implant concept: Cellular and molecular interactions with materials in vivo.

Osteoarthritis (OA) poses significant therapeutic challenges, particularly OA that affects the hand. Currently available treatment strategies are often limited in terms of their efficacy in managing pain, regulating invasiveness, and restoring joint function. The APRICOTⓇ implant system developed by Aurora Medical Ltd (Chichester, UK) introduces a minimally invasive, bone-conserving approach for treating hand OA (https://apricot-project.eu/). By utilizing polycarbonate urethane (PCU), this implant incorporates a caterpillar track-inspired design to promote the restoration of natural movement to the joint. Surface modifications of PCU have been proposed for the biological fixation of the implant. This study investigated the biocompatibility of PCU alone or in combination with two surface modifications, namely dopamine-carboxymethylcellulose (dCMC) and calcium-phosphate (CaP) coatings. In a rat soft tissue model, native and CaP-coated PCU foils did not increase cellular migration or cytotoxicity at the implant-soft tissue interface after 3 d, showing gene expression of proinflammatory cytokines similar to that in non-implanted sham sites. However, dCMC induced an amplified initial inflammatory response that was characterized by increased chemotaxis and cytotoxicity, as well as pronounced gene activation of proinflammatory macrophages and neoangiogenesis. By 21 d, inflammation subsided in all the groups, allowing for implant encapsulation. In a rat bone model, 6 d and 28 d after release of the periosteum, all implant types were adapted to the bone surface with a surrounding fibrous capsule and no protracted inflammatory response was observed. These findings demonstrated the biocompatibility of native and CaP-coated PCU foils as components of APRICOTⓇ implants. STATEMENT OF SIGNIFICANCE: Hand osteoarthritis treatments require materials that minimize irritation of the delicate finger joints. Differing from existing treatments, the APRICOTⓇ implant leverages polycarbonate urethane (PCU) for minimally invasive joint replacement. This interdisciplinary, preclinical study investigated the biocompatibility of thin polycarbonate urethane (PCU) foils and their surface modifications with calcium-phosphate (CaP) or dopamine-carboxymethylcellulose (dCMC). Cellular and morphological analyses revealed that both native and Ca-P coated PCU elicit transient inflammation, similar to sham sites, and a thin fibrous encapsulation in soft tissues and on bone surfaces. However, dCMC surface modification amplified initial chemotaxis and cytotoxicity, with pronounced activation of proinflammatory and neoangiogenesis genes. Therefore, native and CaP-coated PCU possess sought-for biocompatible properties, crucial for patient safety and performance of APRICOTⓇ implant.

Construction of Polycarbonates with Pendant Multifunctional Groups via a One-Step CO2/ Diepoxide Copolymerization Approach.

A "one-step" strategy has been demonstrated for the tunable synthesis of multifunctional aliphatic polycarbonates (APCs) with ethylene oxide (EO), ethylene carbonate (EC), and cyclohexene oxide (CHO) side groups by the copolymerization of 4-vinyl-1-cyclohexene diepoxide with carbon dioxide under an aminotriphenolate iron/PPNBz (PPN = bis(triphenylphosphine)-iminium, Bz = benzoate) binary catalyst. By adjusting the PPNBz-to-iron complex ratio and incorporating auxiliary solvents, the content of functional side groups can be tuned within the ranges of 53-75% for EO, 18-47% for EC, and <1-7% for CHO. The yield and molecular weight distribution of the resulting multifunctional APCs are affected by the viscosity of the polymerization system. The use of tetrahydrofuran as an auxiliary solvent enables the preparation of narrow-distribution polycarbonates at high conversion. This work presents a novel perspective for the preparation of tailorable multifunctional APCs.

Investigation of zinc polycarboxylate cement used in dental treatments in terms of retrospective dosimeter.

Zinc polycarboxylate cement is one of the few dental materials that demonstrate true adhesion to tooth structure. It is suitable for use in living organisms without causing harm. Its strong adhesion to teeth and low level of irritancy are two important parameters for the dental applications. In this study, the dosimetry properties of zinc polycarboxylate cement using thermoluminescence (TL) method were investigated and determined the effectiveness of its use as a good dosimeter. According to the results of this study, the sample shows a good TL properties with three main peaks found around 140°C, 220°C and 330°C. It has a wide linear dose response between 72 Gy and 2.3 kGy and good reusability of the TL peak found at 330°C. Unfortunately, the TL peak intensity values are rapidly faded within a short waiting time interval. Zinc polycarboxylate cement, which is frequently used in dental crowns, can be used as a retrospective dosimeter for measuring the amount of radiation in space studies and nuclear accidents due to its wide linear dose-response curve in the high dose region.

In vitro and in vivo evaluation of the osseointegration capacity of a polycarbonate-urethane zirconium-oxide composite material for application in a focal knee resurfacing implant.

Currently available focal knee resurfacing implants (FKRIs) are fully or partially composed of metals, which show a large disparity in elastic modulus relative to bone and cartilage tissue. Although titanium is known for its excellent osseointegration, the application in FKRIs can lead to potential stress-shielding and metal implants can cause degeneration of the opposing articulating cartilage due to the high resulting contact stresses. Furthermore, metal implants do not allow for follow-up using magnetic resonance imaging (MRI).To overcome the drawbacks of using metal based FKRIs, a biomimetic and MRI compatible bi-layered non-resorbable thermoplastic polycarbonate-urethane (PCU)-based FKRI was developed. The objective of this preclinical study was to evaluate the mechanical properties, biocompatibility and osteoconduction of a novel Bionate® 75D - zirconium oxide (B75D-ZrO2) composite material in vitro and the osseointegration of a B75D-ZrO2 composite stem PCU implant in a caprine animal model. The tensile strength and elastic modulus of the B75D-ZrO2 composite were characterized through in vitro mechanical tests under ambient and physiological conditions. In vitro biocompatibility and osteoconductivity were evaluated by exposing human mesenchymal stem cells to the B75D-ZrO2 composite and culturing the cells under osteogenic conditions. Cell activity and mineralization were assessed and compared to Bionate® 75D (B75D) and titanium disks. The in vivo osseointegration of implants containing a B75D-ZrO2 stem was compared to implants with a B75D stem and titanium stem in a caprine large animal model. After a follow-up of 6 months, bone histomorphometry was performed to assess the bone-to-implant contact area (BIC). Mechanical testing showed that the B75D-ZrO2 composite material possesses an elastic modulus in the range of the elastic modulus reported for trabecular bone. The B75D-ZrO2 composite material facilitated cell mediated mineralization to a comparable extent as titanium. A significantly higher bone-to-implant contact (BIC) score was observed in the B75D-ZrO2 implants compared to the B75D implants. The BIC of B75D-ZrO2 implants was not significantly different compared to titanium implants. A biocompatible B75D-ZrO2 composite approximating the elastic modulus of trabecular bone was developed by compounding B75D with zirconium oxide. In vivo evaluation showed an significant increase of osseointegration for B75D-ZrO2 composite stem implants compared to B75D polymer stem PCU implants. The osseointegration of B75D-ZrO2 composite stem PCU implants was not significantly different in comparison to analogous titanium stem metal implants.

Diselenide-Containing Polymer Based on New Antitumor Mechanism as Efficient GSH Depletion Agent for Ferroptosis Therapy.

Glutathione (GSH) depletion-induced ferroptosis has emerged as a promising treatment for malignant cancer. It works by inactivating glutathione peroxidase 4 (GPX4) and facilitating lipid peroxidation. However, effectively delivering inducers and depleting intracellular GSH remains challenging due to the short half-lives and high hydrophobicity of small-molecule ferroptosis inducers. These inducers often require additional carriers. Herein, diselenide-containing polymers can consume GSH to induce ferroptosis for pancreatic cancer therapy. The diselenide bonds are controllably built into the backbone of the polycarbonate with a targeting peptide CRGD (Cys-Arg-Gly-Asp), which allows for self-assembly into stable nanoparticles (denoted CRNSe) for self-delivery. Significantly, at a concentration of 12 µg mL-1, CRNSe binds to the active site cysteine of GSH resulting in a thorough depletion of GSH. In contrast, the disulfide-containing analog only causes a slight decrease in GSH level. Moreover, the depletion of GSH inactivates GPX4, ultimately inducing ferroptosis due to the accumulation of lipid peroxide in BxPC-3 cells. Both in vitro and in vivo studies have demonstrated that CRNSe exhibits potent tumor suppressive ability with few side effects on normal tissue. This study validates the anti-tumor mechanism of diselenide-containing polymers in addition to apoptosis and also provides a new strategy for inherently inducing ferroptosis in cancer therapy.

Antimicrobial Guanidinylate Polycarbonates Show Oral In Vivo Efficacy Against Clostridioides Difficile.

The emerging antibiotic resistance has been named by the World Health Organization (WHO) as one of the top 10 threats to public health. Notably, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VREF) are designated as serious threats, whereas Clostridioides difficile (C. difficile) is recognized as one of the most urgent threats to human health and unmet medical need. Herein, they report the design and application of novel biodegradable polymers - the lipidated antimicrobial guanidinylate polycarbonates. These polymers showed potent antimicrobial activity against a panel of bacteria with fast-killing kinetics and low resistance development tendency, mainly due to their bacterial membrane disruption mechanism. More importantly, the optimal polymer showed excellent antibacterial activity against C. difficile infection (CDI) in vivo via oral administration. In addition, compared with vancomycin, the polymer demonstrated a much-prolonged therapeutic effect and virtually diminished recurrence rate of CDI. The convenient synthesis, easy scale-up, low cost, as well as biodegradability of this class of polycarbonates, together with their in vitro broad-spectrum antimicrobial activity and orally in vivo efficacy against CDI, suggest the great potential of lipidated guandinylate polycarbonates as a new class of antibacterial biomaterials to treat CDI and combat emerging antibiotic resistance.

A Modular Microfluidic Organoid Platform Using LEGO-Like Bricks.

The convergence of organoid and organ-on-a-chip (OoC) technologies is urgently needed to overcome limitations of current 3D in vitro models. However, integrating organoids in standard OoCs faces several technical challenges, as it is typically laborious, lacks flexibility, and often results in even more complex and less-efficient cell culture protocols. Therefore, specifically adapted and more flexible microfluidic platforms need to be developed to facilitate the incorporation of complex 3D in vitro models. Here, a modular, tubeless fluidic circuit board (FCB) coupled with reversibly sealed cell culture bricks for dynamic culture of embryonic stem cell-derived thyroid follicles is developed. The FCB is fabricated by milling channels in a polycarbonate (PC) plate followed by thermal bonding against another PC plate. LEGO-like fluidic interconnectors allow plug-and-play connection between a variety of cell culture bricks and the FCB. Lock-and-play clamps are integrated in the organoid brick to enable easy (un)loading of organoids. A multiplexed perfusion experiment is conducted with six FCBs, where thyroid organoids are transferred on-chip within minutes and cultured up to 10 d without losing their structure and functionality, thus validating this system as a flexible, easy-to-use platform, capable of synergistically combining organoids with advanced microfluidic platforms.

Reductive depolymerization of polyesters and polycarbonates with hydroboranes by using a lanthanum(III) tris(amide) catalyst.

The homogeneous reductive depolymerization of polyesters and polycarbonates with hydroboranes is achieved with the use of an f-metal complex catalyst. These polymeric materials are transformed into their value-added alcohol equivalents. Catalysis proceeds readily, under mild conditions, with La[N(SiMe3)2]3 (1 mol%) and pinacolborane (HBpin) and shows high selectivity towards alcohols and diols, after hydrolysis.

Synthesis and Characterization of Novel Radiopaque Polycarbonate.

Polymeric materials implanted in the human body are usually invisible under X-ray, and the mixing of heavy metal salts into polymeric materials by physical compounding often poses compatibility problems. A new iodine-containing cyclic carbonate monomer, 4-iodo-N-(2-oxo-1,3-dioxan-5-yl)benzamide (IBTMC), is synthesized, which has a degradable carbonate group as its basic structural unit and iodine atoms attached to the side chain in the form of covalent bonds. The ring-opening polymerization of IBTMC is achieved at room temperature under the catalysis of the solid superbase 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD). The structure and X-ray developing ability of the synthesized polycarbonate are characterized by 1 H-NMR, X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), Gel Permeation Chromatography (GPC), and micro-computed tomography (Micro-CT). The iodine atoms remain bound to the polymer as covalent bonds after a series of reactions and exhibit a high level of X-ray opacity. In vitro degradation experiments of the polymer prove that the polymer is degradable.

Nonwoven Releasing Propolis as a Potential New Wound Healing Method-A Review.

Wound healing poses a serious therapeutic problem. Methods which accelerate tissue regeneration and minimize or eliminate complications are constantly being sought. This paper is aimed at evaluation of the potential use of biodegradable polymer nonwovens releasing propolis as wound healing dressings, based on the literature data. Propolis is honeybee product with antioxidant, antibacterial, antifungal, anticancer, anti-inflammatory, analgesic, and regenerative properties. Controlled release of this substance throughout the healing should promote healing process, reduce the risk of wound infection, and improve aesthetic effect. The use of biodegradable aliphatic polyesters and polyester carbonates as a propolis carrier eliminates the problem of local drug administration and dressing changes. Well-known degradation processes and kinetics of the active substance release allows the selection of the material composition appropriate to the therapy. The electrospinning method allows the production of nonwovens that protect the wound against mechanical damage. Moreover, this processing technique enables adjusting product properties by modifying the production parameters. It can be concluded that biodegradable polymer dressings, releasing a propolis, may find potential application in the treatment of complicated wounds, as they may increase the effectiveness of treatment, as well as improve the patient's life quality.

Elucidating the anticancer activities of guanidinium-functionalized amphiphilic random copolymers by varying the structure and composition in the hydrophobic monomer.

Rationale: Use of traditional anticancer chemotherapeutics has been hindered by the multifactorial nature of multi-drug resistance (MDR) development and metastasis. Recently, cationic polycarbonates were reported as novel unconventional anticancer agents that mitigated MDR and inhibited metastasis. The aim of this study is to explore structure-anticancer activity relationship. Specifically, a series of cationic guanidinium-based random copolymers of varying hydrophobicity was synthesized with a narrow polydispersity (Ð = 1.12-1.27) via organocatalytic ring-opening polymerization (OROP) of functional cyclic carbonate monomers, and evaluated for anticancer activity, killing kinetics, degradability and functional mechanism. Methods: Linear, branched and aromatic hydrophobic side chain units, such as ethyl, benzyl, butyl, isobutyl and hexyl moieties were explored as comonomer units for modulating anticancer activity. As hydrophobicity/hydrophilicity balance of the polymers determines their anticancer efficacy, the feed ratio between the two monomers was varied to tune their hydrophobicity. Results: Notably, incorporating the hexyl moiety greatly enhanced anticancer efficiency and killing kinetics on cancer cells. Degradation studies showed that the polymers degraded completely within 4-6 days. Flow cytometry and lactate dehydrogenase (LDH) release analyses demonstrated that anticancer mechanism of the copolymers containing a hydrophobic co-monomer was concentration dependent, apoptosis at IC50, and both apoptosis and necrosis at 2 × IC50. In contrast, the homopolymer without a hydrophobic comonomer killed cancer cells predominantly via apoptotic mechanism. Conclusion: The hydrophobicity of the polymers played an important role in anticancer efficacy, killing kinetics and anticancer mechanism. This study provides valuable insights into designing novel anticancer agents utilizing polymers.

Wearable Collector for Noninvasive Sampling of SARS-CoV-2 from Exhaled Breath for Rapid Detection.

Airborne transmission of exhaled virus can rapidly spread, thereby increasing disease progression from local incidents to pandemics. Due to the COVID-19 pandemic, states and local governments have enforced the use of protective masks in public and work areas to minimize the disease spread. Here, we have leveraged the function of protective face coverings toward COVID-19 diagnosis. We developed a user-friendly, affordable, and wearable collector. This noninvasive platform is integrated into protective masks toward collecting airborne virus in the exhaled breath over the wearing period. A viral sample was sprayed into the collector to model airborne dispersion, and then the enriched pathogen was extracted from the collector for further analytical evaluation. To validate this design, qualitative colorimetric loop-mediated isothermal amplification, quantitative reverse transcription polymerase chain reaction, and antibody-based dot blot assays were performed to detect the presence of SARS-CoV-2. We envision that this platform will facilitate sampling of current SARS-CoV-2 and is potentially broadly applicable to other airborne diseases for future emerging pandemics.

Preliminary hemocompatibility assessment of an innovative material for blood contacting surfaces.

Over the years, several devices have been created (and the development of many others is currently in progress) to be in permanent contact with blood: mechanical circulatory supports represent an example thereof. The hemocompatibility of these devices largely depends on the chemical composition of blood-contacting components. In the present work, an innovative material (hybrid membrane) is proposed to fabricate the inner surfaces of a pulsatile ventricular chamber: it has been obtained by coupling a synthetic polymer (e.g., commercial polycarbonate urethane) with decellularized porcine pericardium. The hemocompatibility of the innovative material has been preliminarily assessed by measuring its capacity to promote thrombin generation and induce platelet activation. Our results demonstrated the blood compatibility of the proposed hybrid membrane.

4D polycarbonates via stereolithography as scaffolds for soft tissue repair.

3D printing has emerged as one of the most promising tools to overcome the processing and morphological limitations of traditional tissue engineering scaffold design. However, there is a need for improved minimally invasive, void-filling materials to provide mechanical support, biocompatibility, and surface erosion characteristics to ensure consistent tissue support during the healing process. Herein, soft, elastomeric aliphatic polycarbonate-based materials were designed to undergo photopolymerization into supportive soft tissue engineering scaffolds. The 4D nature of the printed scaffolds is manifested in their shape memory properties, which allows them to fill model soft tissue voids without deforming the surrounding material. In vivo, adipocyte lobules were found to infiltrate the surface-eroding scaffold within 2 months, and neovascularization was observed over the same time. Notably, reduced collagen capsule thickness indicates that these scaffolds are highly promising for adipose tissue engineering and repair.

Spatially resolved analysis of Pseudomonas aeruginosa biofilm proteomes measured by laser ablation sample transfer.

Heterogeneity in the distribution of nutrients and oxygen gradients during biofilm growth gives rise to changes in phenotype. There has been long term interest in identifying spatial differences during biofilm development including clues that identify chemical heterogeneity. Laser ablation sample transfer (LAST) allows site-specific sampling combined with label free proteomics to distinguish radially and axially resolved proteomes for Pseudomonas aeruginosa biofilms. Specifically, differential protein abundances on oxic vs. anoxic regions of a biofilm were observed by combining LAST with bottom up proteomics. This study reveals a more active metabolism in the anoxic region of the biofilm with respect to the oxic region for this clinical strain of P. aeruginosa, despite this organism being considered an aerobe by nature. Protein abundance data related to cellular acclimations to chemical gradients include identification of glucose catabolizing proteins, high abundance of proteins from arginine and polyamine metabolism, and proteins that could also support virulence and environmental stress mediation in the anoxic region. Finally, the LAST methodology requires only a few mm2 of biofilm area to identify hundreds of proteins.