Polymer Surface Research Articles

Polystyrene containing 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate with Low Molecular Weight Used As Macroadditive Photostabilizer

Photostabilizer additives are employed to shield polymer materials from ultraviolet (UV) degradation. One category of such additives includes ultraviolet light absorbers (UVA), which absorb radiation and dissipate it within the polymer network as heat. These additives are typically incorporated into the polymer during processing, but they can pose challenges such as low miscibility and migration of the additive to the polymer's surface. A viable solution to these issues is the synthesis of polymers with additives chemically connected to the polymer chain. This work investigates the copolymerization of styrene with the additive 2-[3-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]ethyl methacrylate (BHEM), resulting in the formation of PS-BHEM. This copolymer was then utilized in commercial polymers (PS, HIPS, and ABS) to mitigate degradation, with a comparative analysis of its effectiveness against the commercial stabilizer Tinuvin P. The copolymerization process yields a 92 % product, and the presence of BHEM is confirmed through SEC analysis. Accelerated weather degradation tests indicate that the incorporation of PS-BHEM enhances the UV stabilization of commercial ABS without altering the mechanical properties of the polymers.

Effects of Atmospheric Pressure Plasma Jet on 3D-Printed Acrylonitrile Butadiene Styrene (ABS).

Polymers are essential in several sectors, yet some applications necessitate surface modification. One practical and eco-friendly option is non-thermal plasma exposure. The present research endeavors to examine the impacts of dielectric barrier discharge atmospheric pressure plasma on the chemical composition and wettability properties of acrylonitrile butadiene styrene surfaces subject to the action of additive manufacturing. The plasma source was produced by igniting either helium or argon and then adjusted to maximize the operational conditions for exposing polymers. The drop in contact angle and the improvement in wettability after plasma exposure can be due to the increased oxygen-containing groups onto the surface, together with a reduction in carbon content. The research findings indicated that plasma treatment significantly improved the wettability of the polymer surface, with an increase of up to 60% for both working gases, while the polar index increased from 0.01 up to 0.99 after plasma treatment. XPS measurements showed an increase of up to 10% in oxygen groups at the surface of He-plasma-treated samples and up to 13% after Ar-plasma treatment. Significant modifications were observed in the structure that led to a reduction of its roughness by 50% and also caused a leveling effect after plasma treatment. A slight decrease in the glass and melting temperature after plasma treatment was pointed out by differential scanning calorimetry and broadband dielectric spectroscopy. Up to a 15% crystallinity index was determined after plasma treatment, and the 3D printing process was measured through X-ray diffraction. The empirical findings encourage the implementation of atmospheric pressure plasma-based techniques for the environmentally sustainable manipulation of polymers for applications necessitating higher levels of adhesion and specific prerequisites.

EDNA Adsorption onto Microplastics: Impacts of Water Chemistry and Polymer Physiochemical Properties.

Adsorption of biomacromolecules onto polymer surfaces, including microplastics (MPs), occurs in multiple environmental compartments, forming an ecocorona. Environmental DNA (eDNA), genetic material shed from organisms, can adsorb onto MPs which can potentially either (1) promote long-range transport of antibiotic resistant genes or (2) serve to gain insights into the transport pathways and origins of MPs by analyzing DNA sequences on MPs. However, little is known about the capacity of MPs to adsorb eDNA or the factors that influence sorption, such as polymer and water chemistries. Here we investigated the adsorption of extracellular linear DNA onto a variety of model MP fragments composed of three of the most environmentally prevalent polymers (polyethylene, polyethylene terephthalate, and polystyrene) in their pristine and photochemically weathered states. Batch adsorption experiments in a variety of water chemistries were complemented with nonlinear modeling to quantify the rate and extent of eDNA sorption. Ionic strength was shown to strongly impact DNA adsorption by reducing or inhibiting electrostatic repulsion. Polyethylene terephthalate exhibited the highest adsorption capacity when normalizing for MP specific surface area, likely due to the presence of ester groups. Kinetics experiments showed fast adsorption (majority adsorbed under 30 min) before eventually reaching equilibrium after 1-2 h. Overall, we demonstrated that DNA quickly binds to MPs, with pseudo-first- and -second-order models describing adsorption kinetics and the Freundlich model describing adsorption isotherms most accurately. These insights into DNA sorption onto MPs show that there is potential for MPs to act as vectors for genetic material of interest, especially considering that particle-bound DNA typically persists longer in the environment than dissolved DNA.

Identification and recombinant expression of a cutinase from Papiliotrema laurentii that hydrolyzes natural and synthetic polyesters.

Given the multitude of extracellular enzymes at their disposal, many of which are designed to degrade nature's polymers (lignin, cutin, cellulose, etc.), fungi are adept at targeting synthetic polyesters with similar chemical composition. Microbial-influenced deterioration of xenobiotic polymeric surfaces is an area of interest for material scientists as these are important for the conservation of the underlying structural materials. Here, we describe the isolation and characterization of the Papiliotrema laurentii 5307AH (P. laurentii) cutinase, Plcut1. P. laurentii is basidiomycete yeast with the ability to disperse Impranil-DLN (Impranil), a colloidal polyester polyurethane, in agar plates. To test whether the fungal factor involved in this clearing was a secreted enzyme, we screened the ability of P. laurentii culture supernatants to disperse Impranil. Using size exclusion chromatography (SEC), we isolated fractions that contained Impranil-clearing activity. These fractions harbored a single ~22 kD band, which was excised and subjected to peptide sequencing. Homology searches using the peptide sequences identified, revealed that the protein Papla1 543643 (Plcut1) displays similarities to serine esterase and cutinase family of proteins. Biochemical assays using recombinant Plcut1 confirmed that this enzyme has the capability to hydrolyze Impranil, soluble esterase substrates, and apple cutin. Finally, we confirmed the presence of the Plcut1 in culture supernatants using a custom antibody that specifically recognizes this protein. The work shown here supports a major role for the Plcut1 in the fungal degradation of natural polyesters and xenobiotic polymer surfaces.IMPORTANCEFungi play a vital role in the execution of a broad range of biological processes that drive ecosystem function through production of a diverse arsenal of enzymes. However, the universal reactivity of these enzymes is a current problem for the built environment and the undesired degradation of polymeric materials in protective coatings. Here, we report the identification and characterization of a hydrolase from Papiliotrema laurentii 5307AH, an aircraft-derived fungal isolate found colonizing a biodeteriorated polymer-coated surface. We show that P. laurentii secretes a cutinase capable of hydrolyzing soluble esters as well as ester-based compounds forming solid surface coatings. These findings indicate that this fungus plays a significant role in biodeterioration through the production of a cutinase adept at degrading ester-based polymers, some of which form the backbone of protective surface coatings. The work shown here provides insights into the mechanisms employed by fungi to degrade xenobiotic polymers.

Protecting Orthopaedic Implants from Infection: Antimicrobial Peptide Mel4 Is Non-Toxic to Bone Cells and Reduces Bacterial Colonisation When Bound to Plasma Ion-Implanted 3D-Printed PAEK Polymers.

Even with the best infection control protocols in place, the risk of a hospital-acquired infection of the surface of an implanted device remains significant. A bacterial biofilm can form and has the potential to escape the host immune system and develop resistance to conventional antibiotics, ultimately causing the implant to fail, seriously impacting patient well-being. Here, we demonstrate a 4 log reduction in the infection rate by the common pathogen S. aureus of 3D-printed polyaryl ether ketone (PAEK) polymeric surfaces by covalently binding the antimicrobial peptide Mel4 to the surface using plasma immersion ion implantation (PIII) treatment. The surfaces with added texture created by 3D-printed processes such as fused deposition-modelled polyether ether ketone (PEEK) and selective laser-sintered polyether ketone (PEK) can be equally well protected as conventionally manufactured materials. Unbound Mel4 in solution at relevant concentrations is non-cytotoxic to osteoblastic cell line Saos-2. Mel4 in combination with PIII aids Saos-2 cells to attach to the surface, increasing the adhesion by 88% compared to untreated materials without Mel4. A reduction in mineralisation on the Mel4-containing surfaces relative to surfaces without peptide was found, attributed to the acellular portion of mineral deposition.

Modification of Polysulfide Surfaces with Low‐Power Lasers

AbstractThe modification of polymer surfaces using laser light is important for many applications in the nano‐, bio‐ and chemical sciences. Such capabilities have supported advances in biomedical devices, electronics, information storage, microfluidics, and other applications. In most cases, these modifications require high power lasers that are expensive and require specialized equipment and facilities to minimize risk of hazardous radiation. Additionally, polymer systems that can be easily modified by lasers are often complex and costly to prepare. In this report, these challenges are addressed with the discovery of low‐cost sulfur copolymers that can be rapidly modified with lasers emitting low‐power infrared and visible light. The featured copolymers are made from elemental sulfur and either cyclopentadiene or dicyclopentadiene. Using a suite of lasers with discreet wavelengths (532, 638 and 786 nm) and powers, a variety of surface modifications could be made on the polymers such as controlled swelling or etching via ablation. The facile synthesis and laser modification of these polymer systems were exploited in applications such as direct laser lithography and erasable information storage.

Modification of Polysulfide Surfaces with Low-Power Lasers.

The modification of polymer surfaces using laser light is important for many applications in the nano-, bio- and chemical sciences. Such capabilities have supported advances in biomedical devices, electronics, information storage, microfluidics, and other applications. In most cases, these modifications require high power lasers that are expensive and require specialized equipment and facilities to minimize risk of hazardous radiation. Additionally, polymer systems that can be easily modified by lasers are often complex and costly to prepare. In this report, these challenges are addressed with the discovery of low-cost sulfur copolymers that can be rapidly modified with lasers emitting low-power infrared and visible light. The featured copolymers are made from elemental sulfur and either cyclopentadiene or dicyclopentadiene. Using a suite of lasers with discreet wavelengths (532, 638 and 786 nm) and powers, a variety of surface modifications could be made on the polymers such as controlled swelling or etching via ablation. The facile synthesis and laser modification of these polymer systems were exploited in applications such as direct laser lithography and erasable information storage.

Direct and indirect determination of track etch parameters after sequential UV-C exposure and etching for two swift heavy ions in PADC: Production of rocket-shaped tracks

The present work aimed to study the effect of single-sided UV-C successive exposures and sequential chemical etching on the different track parameters of bulk etch rate, Vb, detector diameter, D, detector length, L, track etch rate, Vt, detection sensitivity, and etched track shape. For this, PADC detectors initially irradiated with high energy-long range ions of 7 GeV Si and 17.48 GeV Ni were used. Fission fragment irradiations were also performed before UV-C exposure to determine the PADC bulk etch rate in exposed and non-exposed UV-C sides. Track parameters of bulk etch rate, Vb, detector diameter, D, detector length, L, track etch rate, Vt, and corresponding sensitivity were determined and compared on both sides. The relative differences between the track parameters on both sides are thus determined. It was found that exposure of PADC detectors to sequential UV-C followed by etching gives a strong increase in the two etching rates, Vb and Vt. Sensitivity measurements indicate that the rate of increase of Vb is greater than that of Vt. Track parameters data by direct track cone length and indirect track diameter versus depth evidence the existence of two regions under the polymer surface. These two regions were attributed to the polymer crosslinking and degradation processes resulting from exposure to UV-C. Region 1 and Region 2 have different etching rates. Region 1 has a constant rate, while Region 2 has an increasing rate as it goes deeper. Sequential UV-C followed by etching makes it possible to generate unusual rocket-shaped (or amphora-shaped) tracks. One possible application of the described technique is the production of nuclear track membranes.

Superhydrophobic surface of biomass carbon-based PANI composite coatings with the biomimetic structure of goose feather for anticorrosion/antibiofilm applications

Biomass carbon (BMC)-based polyaniline (PANI) composite coatings with superhydrophobic biomimetic surfaces were fabricated through nanocasting to transfer the surface of natural goose feather (GF) to the polymer surface for anticorrosion and antibiofilm applications. First, the as-synthesized PANI powder without/with 1 wt% BMC was dissolved/dispersed in N-methyl-2-pyrrolidone and then dropwise added onto the negative soft template of polydimethylsiloxane, successfully transferring the pattern of natural GF surface to a series of biomimetic PANI coating surfaces (denoted by Bio-PANI and Bio-PANI-1). Scanning electron microscopy (SEM) investigated the surface morphology of biomimetic coatings and revealed the presence of micron-sized rachis decorated with many nanoscaled barbules. Compared with that for non-Bio-PANI coating, the contact angle (CA) increased from 92.88° ± 0.81° to 144.94° ± 0.87° for Bio-PANI and 152.46° ± 1.95°for Bio-PANI-1. For anticorrosion application, the electrochemical corrosion potential (Ecorr)/impedance (Z’) of PANI coating increased significantly (from −633.62 mV/7.41 × 105 Ω to −319.87 mV/1.05 × 107 Ω) compared with that of Bio-PANI-1 coating, indicating that the Bio-PANI composite superhydrophobic coating exhibited the best anticorrosion performance. For antibiofilm application, three types of bacteria (i.e., Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) were used to study long-term antibiofilm formation. The findings revealed that the superhydrophobic Bio-PANI-1 coated surface inhibited bacterial growth and hindered biofilm development. Furthermore, the inherent hydrophobicity of this surface played a crucial role in warding off bacterial adhesion, ensuring impressive sustained antibiofilm efficacy.

Electric Field-Assisted Molecularly Imprinted Polymer-Modified QCM Sensor for Enhanced Detection of Immunoglobulin.

In this study, an electric-field-assisted molecularly imprinted polymer (EFAMIP) as an enhanced form of MIP was developed to improve the MIP-modified quartz crystal microbalance (QCM) biosensors. While exerting a vertical electric field, polymerization of methacrylic acid in the presence of immunoglobulin G (IgG) as the template was initiated, and later, after the template removal process, the EFAMIPs were obtained. The polymer surface characterization was conducted by using a scanning electron microscope. The impact of electric field direction on IgG binding sites, forming either EFAMIP-Fab or EFAMIP-Fc, was assessed. Next, the static measurement results in liquid for EFAMIP-modified QCM and MIP-modified QCM were compared. While encompassing IgG, EFAMIP-modified QCMs exhibited up to a 113.5% higher frequency shift than typical MIP in time-limited detection. The final frequency shift of EFAMIP, which determines the detection limit of IgG, was improved up to 12.5% compared to typical MIP. Moreover, the EFAMIP-Fab performance was promising for the selective detection of IgG in a solution containing different types of immunoglobulins.

Smart epoxy coating: g-C3N4 nanosheets loaded MOFs for enhanced anti-corrosion and UV resistance

Large lateral size g-C3N4 nanosheets (Graphite-like carbon nitride) were successfully prepared by surface polymerization. NH2-MIL-101 (Amino-functionalized iron-based metal–organic framework) was then modified on the surface of g-C3N4 nanosheets (NH2-MIL-101@g-C3N4) by an in-situ loading method to construct a long-term smart coating with high barrier, activity inhibition, and anti-UV aging. This novel approach marks a significant advancement in the development of smart coatings for long-term corrosion protection. Evaluation of the active corrosion inhibition of NH2-MIL-101@g-C3N4 (MCN) nanoparticles showed that the corrosion inhibition efficiency of MCN nanoparticles on carbon steel reached 79.3 % after 5 h. The addition of MCN nanoparticles to the epoxy coatings (MCN/EP) endowed the coatings with the ability to actively inhibit corrosion. The release of Fe3+ cations and NH2-BDC (2-aminoterephthalic acid) organic ligands from MCN at defects formed a protective film, effectively preventing further corrosion. The MCN/EP coating maintained a high Log|Z|0.01 Hz value (Impedance modulus at a frequency of 0.01 Hz) during the immersion period with excellent barrier properties. Notably, MCN significantly improved the water resistance, water contact angle, tensile properties, and thermomechanical properties of epoxy coatings after ultraviolet (UV) radiation, highlighting a remarkable enhancement in the coating's performance. The anti-corrosion of MCN/EP coating was unaffected by UV radiation, extending service life of the smart coating, with Log|Z|0.01 Hz values two orders of magnitude higher than pure EP after 300 h of UV radiation. This work presented innovative coating design and preparation methods to improve the performance and functionality of anti-corrosion coatings, making significant attempts in the field.

Tailoring polycarbonate surfaces for improved Ge film adhesion: The role of plasma treatments in 50:50 O2/Ar atmospheres

Polycarbonate (PC) substrates were exposed to plasma environments consisting of a 50:50 mixture of oxygen and argon, and were subsequently coated with germanium (Ge) films grown via sputtering. The hydrophilicity of the PC surfaces was tailored by ion bombardment with energy levels ranging from 50 to 300 eV, which led to a reduction in water contact angles from a native 80° to a superhydrophilic state. Analyses of chemical composition and structure of the PC were performed using X-ray Spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy in Attenuated Total Reflectance geometry (FTIR-ATR), and then correlated to the adhesion of the Ge thin films. Optimal adhesion of the Ge films was achieved by bombarding the PC with ions at energies between 100 and 200 eV, activating the polymer surface while avoiding photodegradation as confirmed by chemical analysis. We report an efficient method for achieving superhydrophilicity of PC within a short treatment time of 60 s that can be effectively integrated in diverse vacuum applications.

Development and characterization of ceramic-polymeric hybrid scaffolds for bone regeneration: incorporating of bioactive glass BG-58S into PDLLA matrix

In recent years, there has been a notable surge of interest in hybrid materials within the biomedical field, particularly for applications in bone repair and regeneration. Ceramic-polymeric hybrid scaffolds have shown promising outcomes. This study aimed to synthesize bioactive glass (BG-58S) for integration into a bioresorbable polymeric matrix based on PDLLA, aiming to create a bioactive scaffold featuring stable pH levels. The synthesis involved a thermally induced phase separation process followed by lyophilization to ensure an appropriate porous structure. BG-58S characterization revealed vitreous, bioactive, and mesoporous structural properties. The scaffolds were analyzed for morphology, interconnectivity, chemical groups, porosity and pore size distribution, zeta potential, pH, in vitro degradation, as well as cell viability tests, total protein content and mineralization nodule production. The PDLLA scaffold displayed a homogeneous morphology with interconnected macropores, while the hybrid scaffold exhibited a heterogeneous morphology with smaller diameter pores due to BG-58S filling. The hybrid scaffold also demonstrated a pH buffering effect on the polymer surface. In addition to structural characteristics, degradation tests indicated that by incorporating BG-58S modified the acidic degradation of the polymer, allowing for increased total protein production and the formation of mineralization nodules, indicating a positive influence on cell culture.

High-throughput BCRP inhibitors screening system based on styrene maleic acid polymer membrane protein stabilization strategy and surface plasmon resonance biosensor

Multidrug resistance (MDR) is a dominant challenge in cancer chemotherapy failure. The over-expression of breast cancer resistance protein (BCRP) in tumorous cells, along with its extensive substrate profile, is a leading cause of tumor MDR. Herein, on the basis of styrene maleic acid (SMA) polymer membrane protein stabilization strategy and surface plasmon resonance (SPR) biosensor, a novel high-throughput screening (HTS) system for BCRP inhibitors has been established. Firstly, LLC-PK1 and LLC-PK1/BCRP cell membranes were co-incubated with SMA polymers to construct SMA lipid particles (SMALPs). PK1-SMALPs were thus immobilized in channel 1 of the L1 chip as the reference channel, and BCRP-SMALPs were immobilized in channel 2 as the detection channel to establish the BCRP-SMALPs-SPR screening system. The methodological investigation demonstrated that the screening system was highly specific and stable. Three active compounds were screened out from 26 natural products and their affinity constants with BCRP were determined. The KD of xanthotoxin, bergapten, and naringenin were 5.14 μM, 4.57 μM, and 3.72 μM, respectively. The in vitro cell verification experiments demonstrated that xanthotoxin, bergapten, and naringenin all significantly increased the sensitivity of LLC-PK1/BCRP cells to mitoxantrone with possessing reversal BCRP-mediated MDR activity. Collectively, the developed BCRP-SMALPs-SPR screening system in this study has the advantages of rapidity, efficiency, and specificity, providing a novel strategy for the in-depth screening of BCRP inhibitors with less side effects and higher efficacy.

Thermodynamic driving forces in contact electrification between polymeric materials

Contact electrification, or contact charging, refers to the process of static charge accumulation after rubbing, or even simple touching, of two materials. Despite its relevance in static electricity, various natural phenomena, and numerous technologies, contact charging remains poorly understood. For insulating materials, even the species of charge carrier may be unknown, and the direction of charge-transfer lacks firm molecular-level explanation. Here, we use all-atom molecular dynamics simulations to investigate whether thermodynamics can explain contact charging between insulating polymers. Based on prior work suggesting that water-ions, such as hydronium and hydroxide ions, are potential charge carriers, we predict preferred directions of charge-transfer between polymer surfaces according to the free energy of water-ions within water droplets on such surfaces. Broad agreement between our predictions and experimental triboelectric series indicate that thermodynamically driven ion-transfer likely influences contact charging of polymers. Furthermore, simulation analyses reveal how specific interactions of water and water-ions proximate to the polymer-water interface explain observed trends. This study establishes relevance of thermodynamic driving forces in contact charging of insulators with new evidence informed by molecular-level interactions. These insights have direct implications for future mechanistic studies and applications of contact charging involving polymeric materials.

Microbial degradation of low-density polyethylene, polyethylene terephthalate, and polystyrene by novel isolates from plastic-polluted environment.

Biodegradation is an eco-friendly measure to address plastic pollution. This study screened four bacterial isolates that were capable of degrading recalcitrant polymers, i.e., low-density polyethylene, polyethylene terephthalate, and polystyrene. The unique bacterial isolates were obtained from plastic polluted environment. Dermacoccus sp. MR5 (accession no. OP592184) and Corynebacterium sp. MR10 (accession no. OP536169) from Malaysian mangroves and Bacillus sp. BS5 (accession no. OP536168) and Priestia sp. TL1 (accession no. OP536170) from a sanitary landfill. The four isolates showed a gradual increase in the microbial count and the production of laccase and esterase enzymes after 4weeks of incubation with the polymers (independent experiment set). Bacillus sp. BS5 produced the highest laccase 15.35 ± 0.19 U/mL and showed the highest weight loss i.e., 4.84 ± 0.6% for PS. Fourier transform infrared spectroscopy analysis confirmed the formation of carbonyl and hydroxyl groups as a result of oxidation reactions by enzymes. Liquid chromatography-mass spectrometry analysis showed the oxidation of the polymers to small molecules (alcohol, ethers, and acids) assimilated by the microbes during the degradation. Field emission scanning electron microscopy showed bacterial colonization, biofilm formation, and surface erosion on the polymer surface. The result provided significant insight into enzyme activities and the potential of isolates to target more than one type of polymer for degradation.

Functional Liquid Metal Polymeric Composites: Fundamentals and Applications in Soft Wearable Electronics

AbstractWearable and self‐healing soft electronics have led to a significant emphasis on their potential in creating versatile, conformable, and sustainable electronic modules. Among conductive additives, Liquid metals (LMs), combining both solid and liquid characteristics, have gained widespread attention due to their versatile physical, chemical, and electrical properties as well as self‐healing capability, biocompatibility, and recyclability. The fluidity of LMs facilitates adaptability to various experimental conditions and components for specific applications. Moreover, the oxide shell on LMs exhibits strong compatibility with surface functionalization and polymerization processes, enhancing the development of reliable composite materials. Herein, an in‐depth analysis of the fundamental properties and characteristics of LMs while addressing their current drawbacks, such as unpredictable reactivity and poor surface stability, is presented. To harness the advantages of LMs, their integration is extensively discussed with polymeric materials through various grafting strategies, leading to the development of macromolecular composites with exceptional softness, solubility, surface functionalization, and versatility. Furthermore, the applications of LMs within LM‐elastomer composites, particularly focusing on their relevance in specific fields such as flexible electronics, are investigated. Finally, LMs' future prospects are emphasized by highlighting their compatibility with self‐healing polymers, thereby providing pathways for major breakthroughs of LMs based devices.

Abstract 2858: Phenotypic screens identify genetic regulators of nanoparticle delivery to pediatric brain tumors

Abstract Pediatric central nervous system tumors are the leading cause of cancer death in children. Diffuse midline glioma (DMG) is a universally fatal pediatric brain tumor and despite many clinical trials over the past decades, less than 10% of patients are long-term survivors. The clinical standard of care is radiotherapy, however it only provides limited symptom relief. There is a clear need to develop creative treatment strategies for patients with DMG. Nanomedicine has the potential to address this challenge, allowing the encapsulation of difficult to deliver therapeutic cargoes, and selectively targeting them to tumors while crossing innate biological barriers. However, a deep understanding of disease-specific nano-bio interactions is crucial to leverage the full potential of these therapies. To functionally validate the role of candidate biomarkers in nanoparticle delivery to DMGs, we performed pooled genetic perturbation screens using a flow based phenotypic output. We developed a lentiviral all-in-one CRISPR/Cas9 knock-out library paired with fluorescence-activated cell sorting to probe the functional impact of 700 genes on the delivery of nanoparticles to DMG. Layer-by-layer electrostatic assembly was used to generate liposomal nanoparticles with a polymer surface coating of hyaluronic acid. Two patient-derived neurosphere models of DMG were transduced with the pooled all-in-one CRISPR/Cas9 library. Following antibiotic selection, cells were incubated with hyaluronic acid or polymeric nanoparticles for 4 or 24 hours and sorted into populations based on nanoparticle affinity. A dynamic cell-sorting strategy was optimized to separate cells infected with inert DNA barcodes based on their degree of nanoparticle-association. DNA was isolated from sorted cells and subjected to next generation sequencing. The enrichment of each single guide was determined relative to matched controls. We found strong agreement between biologic replicates, and determined which genes, when knocked down, shifted nanoparticle uptake into DMG cells. Our pooled phenotypic screen revealed strong biologic regulators of nanoparticle uptake. These can be categorized as formulation dependent and independent, as well as time-dependent. We identified several negative regulators of nanoparticle uptake including members of the mitogen-activated protein kinase (MAPK) and mammalian target of rapamycin (mTOR) pathways. The top target genes are currently being validated in DMG and human neural stem cell models. In ongoing work, we are leveraging genetic and chemical inhibition to sensitize DMG cells to nanoparticle therapeutics. We plan to leverage our screening technique to develop novel combination therapy approaches that could be implemented across multiple administration routes (intravenous, intraventricular, or intratumoral) to enhance the use of nanomedicine for DMG and other pediatric brain tumors. Citation Format: Marissa Coppola, Julianna Kenny-Serrano, John G. Doench, Paula Hammond, Pratiti Bandopadhayay, Jessica W. Tsai, Joelle Straehla. Phenotypic screens identify genetic regulators of nanoparticle delivery to pediatric brain tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2858.

Abstract 7499: Circulating tumor cell enumeration and protein expression by CapioCyte and Allegro Plus imaging

Abstract Radiation or chemoradiation followed by surgical resection is the current standard of therapy for many diseases. These treatments are increasingly supplemented with monoclonal antibodies, such as epidermal growth factor receptor (EGFR)-targeting and programmed death ligand 1 (PD-L1) checkpoint-blocking antibodies. The use of these therapies is typically dependent on solid tissue biopsy to confirm elevated expression of these markers in the solid tumor, which carries complications and may only be sampled at diagnosis. In contrast, a liquid biopsy may detect these markers with minimal invasiveness and at multiple points throughout treatment and recovery. Here, we describe the development of an automated and integrated workflow for circulating tumor cell (CTC) analysis. We previously demonstrated that the CapioCyte method is a highly sensitive approach for enrichment of CTCs using a combination of biomimetic rolling on recombinant E-selectin and antibody-mediated capture on a nanostructured polymer surface within a flow chamber for capture. Here we report a fully automated CapioCyte instrument for CTC purification and immunofluorescence staining using epithelial, white blood cell and nuclear makers to identify and distinguish CTCs from WBCs while also quantifying EGFR or PD-L1 presence on respective CTCs. The immunostaining conditions were developed and validated for high analytical sensitivity and specificity using cell lines and health donor white blood cells with known biomarker status. The final assay conditions were transferred to the CapioCyte for automated immunostaining. CapioCyte enriched and stained CTC samples are paired with the BioView Allegro Plus platform, an imaging and analysis solution using machine learning and customized algorithms for automated imaging and CTC candidate identification based on high-resolution Z-stack images. The reported comprehensive and automated workflow was used to enumerate CTCs in patients with non-small cell lung carcinoma (NSCLC) in a feasibility cohort. Median CTC counts from NSCLC patients was 7.5 CTC/ml (n=26, mean 51.7, range 0.3 - 406.2). Studies are on-going to expand the cohort including testing blood from head and neck cancer patients and respective EGFR and PD-L1 status. The combined and automated CapioCyte-Allegro Plus workflow shows great potential for routine quantification of CTCs and EGFR and PD-L1 status. Citation Format: Ju-heon Lim, Chassidy Johnson, Tal Kaplan, Michael J. Poellmann, Yuval Harari, Elad Kfir, Andrew Z. Wang, Seungpyo Hong. Circulating tumor cell enumeration and protein expression by CapioCyte and Allegro Plus imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7499.

Morphological, Optical and Voronoi Polygon Analysis of Breath Figures Prepared on Polymeric Surface

Background/ Objectives: The formation of breath figures over polymers like polystyrene has vast applications in material science for making numerous micro- and nanopatterned functional surfaces. However, the breath figures (BFs) method is a complex phenomenon as the actual formation of structures are many times unpredictable and the nature of structure depends on the type of polymer, solvent, degree of humidity and additives used. The work presented in this paper deals with the study of condensation on the surface of volatile polystyrene polymer solution and their uses for non-wetting using optical and morphological studies along with mathematical model Voronoi polygon analysis using polystyrene and solvent of benzene and chloroform. The growth dynamics of Breath-Figures (BFs) formed due to condensation is presented in brief. Method: Breath Figure (BF) patterns were prepared by two solvents: benzene and chloroform. Different representative values of relative Humidity viz. 60, 70, 80 and 90 % were employed for making BFs. Two different polymer concentrations of 5 and 10 w/v % was used in this study. Findings: The morphology has been statistically analyzed for different parameters like average diameter and their size distribution etc. In case of BFs formed on benzene surface, droplet has average diameter of about 12 µm at 90% humidity but in case of chloroform surface this diameter is about 25 µm at 90% humidity. Voronoi analysis demonstrates simplistic way to qualitatively check the six-fold order and the coordination numbers in BFs. Novelty: The work shows comparative study of BFs patterns using polystyrene on two different solvents with changing humidity. The study shows morphology of the breath patterns is mainly dependent on the polymer concentration, humidity and density of solvents which is a new observation. The study leads to the acquisition of new knowledge on BFs which provides insight important for various applications including biological fields. Keywords: Breath­figures, Voronoi polygon, Polystyrene, Contact angle, Condensation