Specific Molecular Recognition Research Articles

Low-tech innovation: biomimetic solid-contact potentiometric sensor for nanomolar-level atrazine detection.

Despite the fact that there are already a number of solid-contact-based ion-selective electrodes designed for atrazine detection, our ground-breaking contribution lies in introducing the first-ever atrazine potentioselectrode, enabling the ultra-sensitive detection of atrazine at nanomolar levels. Solid-contact ion-selective electrodes can offer advantages, such as improved stability, reproducibility, sensitivity, and selectivity compared to their liquid-contact counterparts. Here, a biomimetic potentiometric sensor for Atrazine was developed using economic, light weight, and flexible carbon cloth as solid-contact material. Our methodology entails the synthesis of a molecularly imprinted polymer (MIP) through straightforward precipitation polymerization, showcasing a streamlined and efficient method for creating highly specific molecular recognition elements. The validation of template removal is confirmed via meticulous analysis employing EDX and FTIR techniques, ensuring the efficacy of our methodology. The resulting sensing membrane are casted by dispersing the MIP in 2-nitrophenyl octyl ether plasticizer and embedding it within a PVC matrix containing sodium tetraphenyl borate as a lipophilic additive. The developed sensor responds to atrazine in the pH range of 2.8-3.3 over a wide concentration range of 1 × 10-8M to 1 × 10-5M & 1 × 10-5M to 1 × 10-1M with respective slopes of 29.2 mv & 58.7mV and a limit of detection of 1 × 10-9M. An impressive feature of this sensor lies in its swift response time, registering a rapid reaction within a mere 10s. Emphasize the sensor's commendable attributes of reproducibility, selectivity, and sensitivity underscoring its successful application in field monitoring.

Protein Classes Predicted by Molecular Surface Chemical Features: Machine Learning-Assisted Classification of Cytosol and Secreted Proteins.

Chemical structures of protein surfaces govern intermolecular interaction, and protein functions include specific molecular recognition, transport, self-assembly, etc. Therefore, the relationship between the chemical structure and protein functions provides insights into the understanding of the mechanism underlying protein functions and developments of new biomaterials. In this study, we analyze protein surface features, including surface amino acid populations and secondary structure ratios, instead of entire sequences as input for the classifier, intending to provide deeper insights into the determination of protein classes (cytosol or secreted). We employed a random forest-based classifier for the prediction of protein locations. Our training and testing data sets consisting of secreted and cytosol proteins were constructed using filtered information from UniProt and 3D structures from AlphaFold. The classifier achieved a testing accuracy of 93.9% with a feature importance ranking and quantitative boundary values for the top three features. We discuss the significance of these features quantitatively and the hidden rules to determine the protein classes (cytosol or secreted).

Predicting monoclonal antibody binding sequences from a sparse sampling of all possible sequences

Previous work has shown that binding of target proteins to a sparse, unbiased sample of all possible peptide sequences is sufficient to train a machine learning model that can then predict, with statistically high accuracy, target binding to any possible peptide sequence of similar length. Here, highly sequence-specific molecular recognition is explored by measuring binding of 8 monoclonal antibodies (mAbs) with specific linear cognate epitopes to an array containing 121,715 near-random sequences about 10 residues in length. Network models trained on resulting sequence-binding values are used to predict the binding of each mAb to its cognate sequence and to an in silico generated one million random sequences. The model always ranks the binding of the cognate sequence in the top 100 sequences, and for 6 of the 8 mAbs, the cognate sequence ranks in the top ten. Practically, this approach has potential utility in selecting highly specific mAbs for therapeutics or diagnostics. More fundamentally, this demonstrates that very sparse random sampling of a large amino acid sequence spaces is sufficient to generate comprehensive models predictive of highly specific molecular recognition.

Immunological assay using a solid-state pore with a low limit of detection

Emerging infectious diseases, cancer, and other diseases are quickly tested mainly via immune reactions based on specific molecular recognition between antigens and antibodies. By changing the diameter of solid-state pores, biomolecules of various sizes can be rapidly detected at the single-molecule level. The combination of immunoreactions and solid-state pores paves the way for an efficient testing method with high specificity and sensitivity. The challenge in developing this method is achieving quantitative analysis using solid-state pores. Here, we demonstrate a method with a low limit of detection for testing tumor markers using a combination of immunoreactions and solid-state pore technology. Quantitative analysis of the mixing ratio of two and three beads with different diameters was achieved with an error rate of up to 4.7%. The hybrid solid-state pore and immunoreaction methods with prostate-specific antigen (PSA) and anti-PSA antibody-modified beads achieved a detection limit of 24.9 fM PSA in 30 min. The hybrid solid-state pore and immunoreaction enabled the rapid development of easy-to-use tests with lower limit of detection and greater throughput than commercially available immunoassay for point-of-care testing.

Kinetic Proofreading Can Enhance Specificity in a Nonenzymatic DNA Strand Displacement Network.

Kinetic proofreading is used throughout natural systems to enhance the specificity of molecular recognition. At its most basic level, kinetic proofreading uses a supply of chemical fuel to drive a recognition interaction out of equilibrium, allowing a single free-energy difference between correct and incorrect targets to be exploited two or more times. Despite its importance in biology, there has been little effort to incorporate kinetic proofreading into synthetic systems in which molecular recognition is important, such as nucleic acid nanotechnology. In this article, we introduce a DNA strand displacement-based kinetic proofreading motif, showing that the consumption of a DNA-based fuel can be used to enhance molecular recognition during a templated dimerization reaction. We then show that kinetic proofreading can enhance the specificity with which a probe discriminates single nucleotide mutations, both in terms of the initial rate with which the probe reacts and the long-time behavior.

Preferential degradation of ofloxacin on all-organic molecularly imprinted PDI/g-C3N4 photocatalyst via specific molecular recognition

Preferential degradation are urgently needed for detoxification of organic pollutants. Herein, a novel all-organic molecularly imprinted photocatalyst was first constructed by grafting molecularly imprinted perylenediimide (PDI) on graphite-phase carbon nitride (MIP-PDI/g-C3N4) using ofloxacin as template molecule. MIP-PDI/g-C3N4 exhibits higher adsorption capacity for ofloxacin than the non-imprinted counterpart (NIP-PDI/g-C3N4), and shows superior molecular recognition in the mixed solution of ofloxacin and ciprofloxacin. The partition coefficient of MIP-PDI/g-C3N4 for ofloxacin is 3.19 times that for ciprofloxacin, and selection factor of MIP-PDI/g-C3N4 is 1.84 times of NIP-PDI/g-C3N4, suggesting good molecular recognition of MIP-PDI/g-C3N4. The excellent molecular recognition endowed MIP-PDI/g-C3N4 with preferential degradation performance, leading to effective mineralization and detoxification of ofloxacin solution. Most importantly, the preferential degradation mechanism based on molecular recognition was proposed.

The role of promiscuous molecular recognition in the evolution of RNase-based self-incompatibility in plants

How do biological networks evolve and expand? We study these questions in the context of the plant collaborative-non-self recognition self-incompatibility system. Self-incompatibility evolved to avoid self-fertilization among hermaphroditic plants. It relies on specific molecular recognition between highly diverse proteins of two families: female and male determinants, such that the combination of genes an individual possesses determines its mating partners. Though highly polymorphic, previous models struggled to pinpoint the evolutionary trajectories by which new specificities evolved. Here, we construct a novel theoretical framework, that crucially affords interaction promiscuity and multiple distinct partners per protein, as is seen in empirical findings disregarded by previous models. We demonstrate spontaneous self-organization of the population into distinct “classes” with full between-class compatibility and a dynamic long-term balance between class emergence and decay. Our work highlights the importance of molecular recognition promiscuity to network evolvability. Promiscuity was found in additional systems suggesting that our framework could be more broadly applicable.

Rapid and accurate detection of foodborne pathogens: impedimetric immunosensor at the forefront

Microorganisms can be categorized into five categories: bacteria, algae, fungi, viruses, and protozoa which can cause microbiological hazards, contaminating food during production, manufacture, transportation, and storage. Biosensor technology is one of the most reliable and effective analytical technique for determining a biological system's sensitivity and specificity at a very low scale. So many techniques exist for identifying and detecting food-borne illness causing bacteria. But biosensor technology is used to detect and monitor with accuracy, thus increasing its interest globally with time. Biosensors have been used for a long time to illustrate the process of regulating data in the pharmaceutical, food manufacturing, and processing industries. An immunosensor is a type of biosensor that uses the molecular recognition specificity of antigens to form a stable complex of an antibody. It is divided into two subcategories- labeled and label-free. A labeled immunosensor is primarily used to sense the immune reaction and generate signals that allow versatile detection of complex, and detect the microorganisms like Listeria monocytogenes, Salmonella spp., and Escherichia coli. Label-free immunosensors detect physical changes during the immune complex formation and have been explored because of their potential as a specific detection technique which can reduce the time and cost of analysis. It has been developed using several detection methods like optical changes for Salmonella sp., electrochemical changes for Listeria monocytogenes and Escherichia coli, and Hepatitis B. An impedimetric immunosensor for pathogens has been created utilizing a biosensor, electrochemical impedance spectroscopy, antibodies, affinity proteins, affimers, and other binding proteins like bio-receptors, which exhibit good selectivity. This review discusses the techniques used by immunosensors to recognize microorganisms that might cause food poisoning. These techniques consider the electrodes and base-layer components, the makeup and characteristics of distinct bacterial species, as well as the interactions between antigens and antibodies that are utilized to detect bacteria.

A New Perspective on the Biomineralization of Radicular Dentin

The biomineralization of radicular dentin involves complex molecular signaling. The exact mechanism of action remains elusive. However, the literature showed that protein binding sites for calcium ions and mineral precipitation are essential to promote the remineralization process. Dentin organic matrix possesses non-collagenous proteins, such as dentin matrix protein 1 (DMP1), that can initiate and regulate crystal nucleation. Recombinant DMP1 molecules have been thought to perform specific molecular recognition with the apatite surface, guiding calcium phosphate clusters during recruitment through the type I collagen matrix, which serves as a template for controlled biomineralization. The biological basis for the clinical benefits of this process has yet to be completely elucidated. From a clinical perspective, caries, acid erosion, or disinfection protocol treatments can cause dentin demineralization. Given this fact, dentin biomimetic remineralization strategies and treatment strategies aimed at preserving the dentin matrix have been proposed.

Visual Sensor with Host-Guest Specific Recognition and Light-Electrical Co-Controlled Switch.

Perception of UV radiation has important applications in medical health, industrial production, electronic communication, etc. In numerous application scenarios, there is an increasing demand for the intuitive and low-cost detection of UV radiation through colorimetric visual behavior, as well as the efficient and multi-functional utilization of UV radiation. However, photodetectors based on photoconductive modes or photosensitive colorimetric materials are not conducive to portable or multi-scene applications owing to their complex and expensive photosensitive components, potential photobleaching, and single-stimulus response behavior. Here, a multifunctional visual sensor based on the "host-guest photo-controlled permutation" strategy and the "lock and key" model is developed. The host-guest specific molecular recognition and electrochromic sensing platform is integrated at the micro-molecular scale, enabling multi-functional and multi-scene applications in the convenient and fast perception of UV radiation, military camouflage, and information erasure at the macro level of human-computer interaction through light-electrical co-controlled visual switching characteristics. This light-electrical co-controlled visual sensor based on an optoelectronic multi-mode sensing system is expected to provide new ideas and paradigms for healthcare, microelectronics manufacturing, and wearable electronic devices owing to its advantages of signal visualization, low energy consumption, low cost, and versatility.

Polydopamine functionalized dendritic fibrous silica nanoparticles as a generic platform for nucleic acid-based biosensing

Accurate and rapid detection of nucleic acid sequences is of utmost importance in various fields, including disease monitoring, clinical treatment, gene analysis and drug discovery. In this study, we developed a "turn-on" fluorescence biosensor that enables simple and highly efficient detection of nucleic acid biomarkers. Our approach involves the utilization of 6-carboxyfluorescein modified single-stranded DNA (FAM-ssDNA) as molecular recognition element, along with polydopamine-functionalized dendritic fibrous nanosilica (DFNS). FAM-ssDNA serves as both specific molecular recognition element for the target analyte and reporter capable of transducing a detectable signal through Watson–Crick base pairing. The polydopamine-functionalized DFNS (DFNS@DA) exhibits strong binding to FAM-ssDNA via polyvalent metal mediated coordination leading to effective quenching by fluorescence resonance energy transfer. In the presence of a complementary target sequence, FAM-ssDNA forms hybridized structure and detaches from DFNS@DA, which causes an increased fluorescence emission. The analytical system based on FAM-ssDNA and DFNS@DA demonstrates exceptional sensitivity, selectivity, and rapid response for the detection of nucleic acid sequences, leveraging the high adsorption and quenching properties of DFNS@DA. For the first proof of concept, we demonstrated the successful detection of microRNA (miR-21) in cancer cells using the FAM-ssDNA/DFNS@DA system. Our results highlight the promising capabilities of DFNS@DA and nucleic acid-based biosensors, offering a generic and cost-effective solution for the detection of nucleic acid-related biomarkers.Graphical abstract

Zr-NMOF tagged with heterobifunctionalized aptamers for highly sensitive, multiplexed and rapid imaging mass cytometry.

Imaging mass cytometry (IMC) permits high-dimensional single-cell spatial proteomics by harnessing mass tags to replace conventional fluorescence tags. However, the current IMC technique commonly adopts metal-chelated polymer (MCP) tags, which are limited in sensitivity, multiplicity and data acquisition speed. Here, we demonstrate nanometal-organic framework (NMOF) tags, which could concurrently augment IMC's sensitivity, multiplicity, and acquisition speed. We designed and synthesized uniform-sized Zr-NMOFs (∼31 nm, PDI < 0.1) and then functionalized them with heterobifunctionalized aptamers containing phosphate groups and fluorescent moieties to generate Zr-NMOF_Aptamer probes. Such functionalization enabled direct ligand exchange with zirconium ions on Zr-NMOFs, thus allowing for concurrent fluorescence and mass signal acquisitions. The fluorescence signal enabled large-scale rapid imaging to quickly locate the region-of-interest, therefore significantly reducing IMC's blind scanning time and compensating for IMC's lower resolution. Meanwhile, the Zr-NMOF_Aptamer probe exhibited specific molecular recognition and a fourfold enhancement in signal amplification over the commercial MCP probe. Additionally, we showed that Zr-NMOF_Aptamer probes were compatible with commercial MCP probes for high-multiplex co-staining in IMC analysis. The Zr-NMOF_Aptamer probe represents a promising development of next-generation molecular probes for spatial proteomics with IMC.

Facile and green synthesis of a hydrophilic imprinted resin in a deep eutectic solvent–water medium for the specific molecular recognition of tumor biomarkers in complex biological matrices

A novel and environmentally friendly strategy was developed to synthesize a hydrophilic molecularly imprinted resin in a deep eutectic solvent–water medium, achieving exceptional molecular recognition of tumor biomarkers in complex biological sample.

Light-regulated morphology control in supramolecular polymers.

Stimuli-responsive materials have gained significant recent interest owing to their versatility and wide applications in fields ranging from materials science to biology. In the majority of examples, external stimuli, including light, act as a remote source of energy to depolymerize/deconstruct certain nanostructures or provide energy for exploring their functional features. However, there is little emphasis on the creation and precise control of these materials. Although significant progress has been made in the last few decades in understanding the pros and cons of various directional non-covalent interactions and their specific molecular recognition ability, it is only in the recent past that the focus has shifted toward controlling the dimension, dispersity, and other macroscopic properties of supramolecular assemblies. Control over the morphology of supramolecular polymers is extremely crucial not only for material properties they manifest but also for effective interactions with biological systems for their potential application in the field of biomedicine. This could effectively be achieved using photoirradiation which has been demonstrated by some recent reports. The concept as such offers a broad scope for designing versatile stimuli-responsive supramolecular materials with precise structure-property control. However, there has not yet been a compilation that focuses on the present subject of employing light to impact and regulate the morphology of supramolecular polymers or categorize the functional motif for easy understanding. In this review, we have collated recent examples of how light irradiation can tune the morphology and nanostructures of supramolecular polymers and categorized them based on their chemical transformation such as cis-trans isomerization, cycloaddition, and photo-cleavage. We have also established a direct correlation among the structures of the building blocks, mesoscopic properties and functional behavior of such materials and suggested future directions.

A DMSO-assisted iridium(III) complex as a luminescent "turn-on" sensor for selective detection of L-histidine and bacterial imaging.

Histidine (His) is a semi-essential amino acid and a unique key neurotransmitter involved in numerous physiological processes. An excessive or deficient amount of His in the body can lead to various related diseases. However, since the chemical structures of L-His and its metabolites (such as histamine (Ha), imidazole-4-acetate (ImA), etc.) are very similar, simple and efficient selective detection of L-His and its related metabolites is of great importance but remains a great challenge. Herein, we successfully designed and synthesized a DMSO-assisted iridium(III) complex (Ir1-DMSO), which can be applied as a "turn-on" photoluminescence (PL) probe for the selective detection and quantification of L-His/Ha. More importantly, Ir1-DMSO exhibited good sensitivity, high selectivity, and anti-interference capability for L-His/Ha/His-containing proteins, which is advantageous due to its simple fabrication and low technical demands. This was attributed to the reaction of Ir1-DMSO with imidazole and amino groups of L-His/Ha. Furthermore, we show the utility of Ir1-DMSO as a PL imaging agent in cultures of E. coli and S. aureus. Considering its diversity of composition and structural flexibility, it can be extended to other solvents and Ir-ligand complexes for various analyses based on specific molecular recognition sensing platforms.

Abstract A032: Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer

Abstract Chemotherapy is a widely used systemic treatment modality for cancer treatment as it kills the rapidly dividing cells. However, the administered chemo-drugs cause systemic toxicity, have fast degradation rate at physiological conditions hence low bioavailability and poor tumor accumulation. These shortcomings can be mitigated by the use of tumor targeting drug delivery systems. The nanoparticles can further be tailor made according to physiological conditions of the tumor microenvironment. Herein, the redox responsive polymer has been synthesized by introducing the disulphide linkage in the polymer. The drug release profile indicated the release of the drug is more efficient in presence of 10mM Dithiothreitol(reducing agent for disulphide linkage) when compared to 0mM dithiothreitol. In this context, this study investigates the therapeutic efficacy of THP-doxorubicin encapsulated in polylactic acid based redox responsive nanoparticle(NP) whose surface have been modified with tumor (4T1) and macrophage (J774) cell membranes. The coated cell membrane provides advantages such as immune escape, long blood circulation time, specific molecular recognition and cell targeting. The prepared nanoparticles have a hydrodynamic size of 210±10 nm with zeta potential of -30±3 mV. The cellular internalization studies of free drug vs the cell membrane coated NPs (CMNPs) were done and it was confirmed that CMNPs were internalized more efficiently in one hour drug incubation study. The same was confirmed when cancer cell proliferation inhibition assay was done, and half maximal inhibitory concentration of free drug, uncoated NPs and CMNPs were 0.31µM , 0.463µM and 0.137µM respectively. This study provides the synthesis and characterization of redox responsive polymer, preparation of cell membrane coated nanoparticles and in-vitro studies for the same. This study has a future scope in the field of personalized medicine at much cheaper price when compared to active targeting methods by antibodies, CART, proteins etc. Citation Format: Harshdeep Kaur, Harpal Singh, Neetu Singh. Cell membrane coated- Biomimetic biodegradable nanoparticles for tumor targeted delivery of THP-doxorubicin using polylactic acid based redox responsive polymer [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A032.

A-365 Carbohydrate-binding Module Proteins to Functionalize Paper for Lateral Flow Applications

Abstract Background Lateral flow (LF) tests have employed nitrocellulose membrane since their introduction. Refinement of nitrocellulose and LF production techniques have led to substantial improvements in reproducibility, sensitivity, clarity, and speed of results. The recent surge in demand for LF tests during the COVID-19 pandemic has drawn increased attention to the consequences of using non-biodegradable or non-recyclable materials in test production, requiring disposal via landfill. The nitrocellulose substrate is a critical component for substitution with an equivalent or superior material to address environmental concerns. Additionally, nitrocellulose and the specific molecular recognition reagents, typically antibodies, contribute significantly to the test cost, and whilst LF tests are less expensive than most other formats, challenges remain with respect to providing affordable tests with adequate performance globally in low resource environments. Despite attempts to substitute cellulose for nitrocellulose, principally for reducing cost and more latterly, environmental impact, cellulose is not widely used due to inferior performance, especially in relation to the clarity and quality of the signal line and reagent requirements. Here, we present preliminary data supporting the use of cellulose membrane (paper) as an alternative substrate to nitrocellulose for LF assays. We demonstrate that cellulose-binding module (CBM)-streptavidin fusion proteins for the immobilisation of capture antibodies on cellulose addresses the performance limitations, yielding sensitivity, clarity and speed of result matching current clinical and industry requirements for a qualitative SARS-CoV-2 antigen LF test. Methods We expressed and purified CBM-streptavidin fusion proteins from E.coli to a purity of &amp;gt;90%. Binding to biotinylated proteins and cellulose material was confirmed. An inhouse SARS-CoV-2 antigen assay was adapted for use with the CBM-streptavidin fusion protein on cellulose material. Using methods compatible with current LF test production, we conjugated and dried down 40nm gold (BBI) with anti-nucleocapsid antibodies (Hytest). The biotinylated anti-nucleocapsid capture antibody was dried down on a separate pad. CBM-streptavidin fusion protein was plotted on Whatman 43 paper at the test line. We evaluated assay performance using SARS-CoV-2 nucleocapsid protein and UV-inactivated SARS-CoV-2 virus (NIBSC) in artificial mucus. We further evaluated accelerated stability of the CBM-paper system at 45°C. Results Plotting of the CBM-fusion protein on the test line (0.3 mg/mL, 1 uL/cm) resulted in a tightly focused line, while the control line antibody, without CBM-fusion protein (1 mg/mL, 1 uL/cm), diffused from its deposition line. Additionally, we were able to substantially reduce the amount of capture antibody needed using the CBM-fusion protein system. The cellulose-based assay exhibited a runtime of 30 minutes and an analytical sensitivity of 10^3 pfu/mL. No significant changes in performance were observed after 9 weeks of incubation at 45°C, representing an approximate accelerated shelf-life of 12 months. Conclusion Our results indicate that paper-based tests match sensitivity, clarity, and speed of current qualitative antigen tests on nitrocellulose, with a shelf-life of at least one year. This preliminary investigation demonstrates the viability of using paper as a replacement for nitrocellulose when coupled with CBM-fusion proteins for antibody immobilisation, offering significantly reduced material cost and environmental impact.

Recent applications of macrocycles in supramolecular catalysis

Numerous supramolecular macrocycles have been utilized for developing catalysts by exploiting their specific molecular recognition and ability to form inclusion complexes through noncovalent interactions. The cyclic structure and modified functional groups of these macrocycles can influence substrate and transition state stability, as well as reaction selectivity. The inner cavities of these macrocycles are particularly beneficial, as they enable substrates to adopt preorganized arrangements and serve as versatile platforms for highly efficient supramolecular catalytic systems. This minireview provides an overview of recent advancements in supramolecular catalysis using various macrocycles, such as crown ethers, cyclodextrins, calixarenes, pillararenes, cucurbiturils, and other novel macrocycles.

Instant Detection of Synthetic Cannabinoids on Physical Matrices, Implemented on a Low-Cost, Ultraportable Device.

Synthetic cannabinoids (SCs) make up a class of novel psychoactive substances (NPS), used predominantly in prisons and homeless communities in the U.K. SCs can have severe side effects, including psychosis, stroke, and seizures, with numerous reported deaths associated with their use. The chemical diversity of SCs presents the major challenge to their detection since approaches relying on specific molecular recognition become outdated almost immediately. Ideally one would have a generic approach to detecting SCs in portable settings. The problem of SC detection is more challenging still because the majority of SCs enter the prison estate adsorbed onto physical matrices such as paper, fabric, or herb materials. That is, regardless of the detection modality used, the necessary extraction step reduces the effectiveness and ability to rapidly screen materials on-site. Herein, we demonstrate a truly instant generic test for SCs, tested against real-world drug seizures. The test is based on two advances. First, we identify a spectrally silent region in the emission spectrum of most physical matrices. Second, the finding that background signals (including from autofluorescence) can be accurately predicted is based on tracking the fraction of absorbed light from the irradiation source. Finally, we demonstrate that the intrinsic fluorescence of a large range of physical substrates can be leveraged to track the presence of other drugs of interest, including the most recent iterations of benzodiazepines and opioids. We demonstrate the implementation of our presumptive test in a portable, pocket-sized device that will find immediate utility in prisons and law enforcement agencies around the world.

Complementary Supramolecular Functionalization Enhances Antifouling Surfaces: A Ureidopyrimidinone-Functionalized Phosphorylcholine Polymer.

Fibrosis of implants remains a significant challenge in the use of biomedical devices and tissue engineering materials. Antifouling coatings, including synthetic zwitterionic coatings, have been developed to prevent fouling and cell adhesion to several implantable biomaterials. While many of these coatings need covalent attachment, a conceptually simpler approach is to use a spontaneous self-assembly event to anchor the coating to a surface. This could simplify material processing through highly specific molecular recognition. Herein, we investigate the ability to utilize directional supramolecular interactions to anchor an antifouling coating to a polymer surface containing a complementary supramolecular unit. A library of controlled copolymerization of ureidopyrimidinone methacrylate (UPyMA) and 2-methacryloyloxyethyl phosphorylcholine (MPC) was prepared and their UPy composition was assessed. The MPC-UPy copolymers were characterized by 1H NMR, Fourier transform infrared (FTIR), and gel permeation chromatography (GPC) and found to exhibit similar mol % of UPy as compared to feed ratios and low dispersities. The copolymers were then coated on an UPy elastomer and the surfaces were assessed for hydrophilicity, protein absorption, and cell adhesion. By challenging the coatings, we found that the antifouling properties of the MPC-UPy copolymers with more UPy mol % lasted longer than the MPC homopolymer or low UPy mol % copolymers. As a result, the bioantifouling nature could be tuned to exhibit spatio-temporal control, namely, the longevity of a coating increased with UPy composition. In addition, these coatings showed nontoxicity and biocompatibility, indicating their potential use in biomaterials as antifouling coatings. Surface modification employing supramolecular interactions provided an approach that merges the simplicity and scalability of nonspecific coating methodology with the specific anchoring capacity found when using conventional covalent grafting with longevity that could be engineered by the supramolecular composition itself.